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Ravichandran, Pravin Karthick, and Santhosh Keerthi Balmuri. "Evaluation of different Cloud Environments and Services related to large scale organizations(Swedish Armed forces)." Thesis, Malmö högskola, Fakulteten för teknik och samhälle (TS), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20556.
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Cloud Computing (CC) is one of the fast growing computer network technologies and many companies offer their services through cloud network. Cloud Computing has many properties with respect to the existing traditional service provisions like scalability, availability, fault tolerance, capability and so on which are supported by many IT companies like Google, Amazon, Salesforce.com. These IT companies have more chances to adapt their services into a new environment, known as Cloud computing systems. There are many cloud computing services which are being provided by many IT companies.The purpose of this thesis is to investigate which cloud environment (public, private and hybrid) and services (Infrastructure as a Service, Software as a Service, and Platform as a Service) are suitable for Swedish Armed Forces (SWAF) with respect to performance, security, cost, flexibility and functionality. SWAF is using private (internal) cloud for communications where both sensitive and non-sensitive information are located in the internal cloud. There are problems like maintenance of hardware, cost issues and secure communication while maintaining the private cloud. In order to overcome those problems we have suggested a hybrid and community cloud environment and SaaS, IaaS, PaaS services for SWAF.For suggesting these cloud environments and cloud services we have performed a literature study and two empirical studies (survey and interviews) with different organizations.A new cloud model is designed based on the suggested cloud environment, separate storage spaces for sensitive and non-sensitive information, suitable services and an effective infrastructure for sharing the internal information for SWAF.
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Billman, Gregory M. "The Inherent Limitations of Spacepower Fact or Fiction? /." Maxwell AFB, Ala. : Air University Research Coordinator Office, 1998. http://www.au.af.mil/au/database/research/ay1995/saas/billmagm.htm.
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Thesis (M.M.A.S.)--School of Advanced Airpower Studies, 1995.<br>Subject: Whether spacepower's limitations are predominantly inherent to the space environment or are self-imposed by the current US approach to space. Cover page date: [1995]. Vita. Includes bibliographical references.
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Dichello, Gennaro. "Investigating self-assembling nanomaterials (Sans) within a biological environment." Thesis, University of Brighton, 2017. https://research.brighton.ac.uk/en/studentTheses/a0fb3b71-dd3f-41de-a58c-2bb427e8eade.
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Nanomaterials are defined as structures possessing one or more dimensions below 100 nanometres in size. They display unique properties that arise as a result of quantum behaviours, owing to their high surface area to volume ratios. Self-assembling nanomaterials (SANs), where individual components referred to as “building blocks” spontaneously organise into complex structural arrangements, is a prominent field that offers technological innovation within medicine and beyond. To effectively exploit this approach in healthcare however, a high-level of behavioural understanding within biological systems is required, which has yet to be ascertained. Accordingly, work undertaken in this thesis aimed to investigate how gold nanoparticles self-assemble and interact within a biological environment. Molecular recognition and electrostatic attraction, two different underpinning mechanisms of self-assembly were studied. Based on findings within this thesis, the latter approach was chosen for further development. Corresponding functional gold nanoparticles were incorporated into PEGylated liposomes using a novel method and extensively characterised. Comparative cytotoxicity evaluation was carried out in vitro on a male Chinese hamster lung fibroblast cell line (V79), employing MTT and LDH assays. Investigations focused on identifying any differences in biological response after treatment with individually dispersed gold nanoparticles and as they underwent in situ self-assembly. Cellular uptake and any ensuing self-assembly was investigated using a combination of electron microscopy and elemental analysis on thin-sectioned specimens. Results presented in this thesis reveal that both electrostatic interactions and molecular recognition facilitate self-assembly under aqueous conditions. Within a biologically relevant medium however, considerable nanoparticlebiomolecule complex formation occurs and only particles exploiting electrostatic interactions persist to self-assemble. Gold nanoparticles were capable of being encapsulated within liposomes by exploiting electrostatic attractions between oppositely charged lipids and ligands on particle surfaces. The novel method resulted in variable internalised gold to lipid ratios, hypothesised to result from differing magnitudes of electrostatic attraction during preparation. At clinically relevant concentrations, gold nanoparticles functionalised with cationic or anionic ligands did not display significant cytotoxicity. A significant difference in cytotoxicity was displayed as they underwent in situ assembly however. Cellular internalisation of gold was evidenced, with nanoparticles seen to accumulate and reside within cellular vacuoles, but no confirmation of self-assembly was obtained. In conclusion, the current work provides further knowledge regarding the feasibility, risk and current limitations associated with utilising and evaluating nanomaterials for in-situ self-assembly within biological environments. Extensive interactions shown to occur between initial building blocks and biological components can hinder self-assembly activity, highlighting the importance of rational design when manufacturing SANs. Individual nanoparticles were encapsulated within surface-modified liposomes, demonstrating a possible strategy towards implementing further control over SANs. Cellular studies identified a difference in toxicity between individual building blocks and their assembled suprastructures, demonstrating that unique biological responses could arise from the self-assembly of SANs. Evaluation of intracellular self-assembly and the ability to differentiate between individual building blocks, assembled suprastructures and cellular components is inherently difficult. Current techniques and approaches require further development to enable routine and reliable assessment of analogous in situ self-assembling nanosystems.
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Savic, Trifun. "Localization in Constrained Environments." Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS232.
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Cette thèse se concentre sur la localisation à faible puissance dans des environnements contraints, sans nécessiter d'infrastructure de localisation. Nous considérons deux cas d'utilisation cibles: la localisation de bateaux dans un port de plaisance, et la localisation de robots mobiles dans un environnement intérieur. Nous commençons par évaluer deux systèmes de localisation en temps réel ("Real Time Localition System" en anglais, RTLS) basés sur les radiofréquences (Bluetooth Angle-of-Arrival et Ultra-Wide Band ranging). Leurs principaux inconvénients sont qu'ils nécessitent le déploiement préalable de points d'ancrage, et qu'ils ne sont pas à faible consommation, ce qui les rend peu compatibles avec nos cas d'utilisation cibles. Ce travail contribue à remédier à ces inconvénients en proposant deux nouveaux systèmes: WELOC et Blip. Nous proposons également RRDV, une solution de détection de rencontre de robots pour les systèmes multi-robots. WELOC est un système de localisation basé sur les ultrasons qui réutilise les capteurs de détection de présence des bateaux déjà présents dans la marina. Il comporte un système de programmation qui déclenche l'émetteur-récepteur ultrasonique de chaque capteur de présence à des moments précis. WELOC présente le design d'un appareil mobile alimenté par batterie, capable de communiquer en toute sécurité à la fois par ultrasons et par signaux radio, et conçu à partir de composants disponibles sur le marché. Des essais en conditions réelles dans un port de plaisance dans le sud de la France montrent que l'appareil mobile peut être localisé avec une précision de l'ordre du centimètre, tout en étant à une distance de 10 m des capteurs de présence. Blip est un système d'identification des bateaux dans un port de plaisance, qui ne nécessite qu'une mise à jour logicielle des systèmes de capteurs intelligents existants dans les ports de plaisance. Il utilise les informations fournies par les capteurs de surveillance des bateaux déjà présents (installés dans la cabine d'un bateau) et les combine avec les informations provenant de l'infrastructure fixe des capteurs de présence pour identifier les bateaux sur les emplacements. Lors de nos essais en conditions réelles, le système a fait preuve d'une précision de 100 % dans l'identification des bateaux. Cette thèse propose également RRDV, un système de détection de rencontres entre robots dans un système multi-robots. De nombreux robots sont déjà équipés d'un capteur à ultrasons pour mesurer leur distance à des objets devant eux. RRDV est une mise à jour logicielle pour ces robots, leur permettant d'utiliser ces capteurs à ultrasons pour détecter les rencontres avec d'autres robots. En testant RRDV sur un système multi-robots réel, il détecte correctement 96.7% des fois où deux robots se font face pendant 5 s ou plus. La thèse contribue au domaine de recherche croissant de la localisation et des communications sans-fil à faible consommation, en proposant des solutions innovantes pour des systèmes de localisation précis et à faible consommation dans des environnements contraints. Ces solutions ont des applications non seulement dans l'industrie maritime mais aussi dans les systèmes multi-robots. La thèse démontre l'efficacité des systèmes basés sur les ultrasons et met en évidence le potentiel du matériel ubiquitaire prêt à l'emploi pour le développement de systèmes de localisation<br>This thesis focuses on low-power localization in constrained environments, without the need for localization infrastructure. We consider two target use cases: localizing boats in a marina, and localizing mobile robots in an indoor environment. We start by evaluating two RF-based Real-Time Localization Systems (RTLS), based on Bluetooth Angle-of-Arrival and Ultra-Wide Band ranging. Their main drawbacks are that they require the prior deployment of anchors and are not low power, making them poorly compatible with our target use cases. This work contributes to addressing these drawbacks by proposing two novel systems: WELOC and Blip. We further propose RRDV, a robot encounter detection solution for multi-robot systems. WELOC is an ultrasound-based localization system that re-purposes boat presence detection sensors already deployed in the marina. It features a scheduling scheme that triggers each presence sensors' ultrasonic transceiver at specific times. WELOC introduces a battery-powered mobile device capable of securely communicating with both ultrasound and radio signals, designed entirely from off-the-shelf components. Real-world tests in a real-life marina in the South of France show a mobile device can be localized with cm-level accuracy when it is up to 10 m away from presence sensors. Blip is a system for boat identification in a marina, which only requires a software update to existing smart marina sensor systems. It uses the information from already installed boat monitoring sensors (mounted in a boat's cabin), and combines that with the information from the fixed infrastructure of presence sensors to identify boats on slips. In our real-world tests, the system exhibits 100 % boat identification accuracy. This thesis further proposes RRDV, a system for detecting robot-to-robot encounters in a multi-robot system. Many robots are already equipped with an ultrasound sensor for measuring the distance to objects in front of them. RRDV is a software update to those robots, allowing them to use those ultrasound sensors for detecting encounters with other robots. When testing RRDV on a real-world multi-robot system, it correctly detects 96.7% of the times two robots face one another for 5~s or more. The thesis contributes to the growing research field of localization and low-power wireless by proposing innovative solutions for low-power and accurate localization in constrained environments. While these solutions have countless applications well beyond the ones outlined in this thesis, we chose the use cases of localization of boats in marinas and localization of robots in an indoor environment to remain perfectly focused. The thesis demonstrates the effectiveness of ultrasound-based systems and highlights the potential of ubiquitous off-the-shelf hardware for the development of localization systems
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Saade, Christelle. "Structure and function in solution of the transmembrane protein mTSPO in different amphiphilic systems : from detergents to biomimetic environments." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASF038.
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TSPO est une petite protéine membranaire translocatrice, ubiquitaire, composée de cinq hélices-α transmembranaires. Chez les mammifères, elle est principalement localisée dans la membrane externe des mitochondries, où elle jouerait un rôle dans le transport du cholestérol et la voie de synthèse des stéroïdes. Cette protéine présente un intérêt pharmacologique majeur en raison de sa forte affinité pour de nombreux ligands utilisés comme marqueurs de l'inflammation en neuro-imagerie. La seule structure atomique connue des TSPOs de mammifères est la structure RMN (2MGY.PDB) de la TSPO de souris (mTSPO). Cependant, cette structure est controversée, car obtenue en repliant la protéine dans une concentration forte de détergent DPC et en présence du ligand (R)-PK11195, qui la rigidifie fortement. En l'absence de ligand, la structure de mTSPO est trop flexible pour être résolue par RMN. De plus, à ce jour, aucune condition amphiphile n'a permis de cristalliser les TSPOs de mammifères, avec ou sans ligand, contrairement aux TSPOs bactériennes.L'objectif de cette étude est de déterminer, par une approche structure/fonction, l'effet de différents environnements amphiphiles sur la structure de mTSPO en condition “apo” (i.e. sans ligand). Nous avons sondé sa structure en solution à différentes échelles par des techniques de diffusion de rayonnement et de spectroscopie optique. En particulier, la diffusion de rayons X et de neutrons aux petits angles (SAXS et SANS), combinée à la chromatographie d'exclusion stérique (SEC), la variation de contraste en SANS et la modélisation ab initio, a permis d'obtenir la conformation du complexe entier mTSPO/amphiphiles et de sonder spécifiquement celles de la protéine et de la bouée d'amphiphiles. La quantité de molécules d'amphiphiles associés à mTSPO, mesurée par MALLS, a permis de valider les modèles proposés. L'effet de l'environnement sur l'affinité du ligand a été mesuré par thermophorèse à micro-échelle (MST).L'apo-mTSPO, produite par voie recombinante dans les corps d'inclusion de la bactérie E. coli, est partiellement dépliée suite à son extraction par le SDS. Nous montrons que la protéine se replie en DPC à la fois au niveau local (augmentation significative de la quantité et des interactions des hélices-α et de la fluorescence des tryptophanes) et au niveau tridimensionnel avec une conformation “apo” plus étendue que la structure RMN 2MGY.PDB. En ajoutant des phospholipides DMPC, pour obtenir un environnement de bicelles mixtes DMPC:DPC partiellement biomimétique, l'apo-mTSPO se structure davantage : la quantité d'hélices-α et leurs interactions augmentent significativement, ainsi que la fluorescence des tryptophanes. Ce repliement est associé à une augmentation significative de l'affinité de la protéine pour le ligand (R)-PK11195 (0.9 µM) comparée à celle en DPC (70 µM) et SDS (absence d'affinité). Nous démontrons ainsi la pertinence de l'utilisation de bicelles DMPC:DPC pour l'étude en solution des protéines membranaires et confirmons le rôle crucial des lipides dans la structure et la fonction de mTSPO. Enfin, nous montrons que cet environnement est favorable à la cristallisation de l'apo-mTSPO et à la reconstitution de la protéine dans des nanodisques de DMPC.Pour comparer ces résultats avec une protéine exprimée en condition native, nous avons développé un nouveau protocole de production de mTSPO en levures. Nous avons réussi à purifier la protéine en condition “apo” en DDM, un détergent connu pour solubiliser les protéines correctement repliées tout en conservant des lipides membranaires associés. Ces travaux de thèse (i) contribuent à une meilleure compréhension de la structure/fonction de mTSPO dans différents environnements amphiphiles, pour déterminer les conditions optimales à des études structurales à plus haute résolution, et (ii) constituent un apport méthodologique significatif pour l'étude des protéines membranaires en solution<br>TSPO is a small, ubiquitous, translocator membrane protein composed of five transmembrane α-helices. In mammals, it is primarily located in the outer mitochondrial membrane, where it is believed to play a role in cholesterol transport and steroid synthesis pathways. This protein has significant pharmacological interest due to its affinity for various ligands used as markers of inflammation in neuroimaging. The only known atomic structure of mammalian TSPOs is the NMR structure (2MGY.PDB) of mouse TSPO (mTSPO). However, this structure is controversial as it was obtained by refolding the protein using a high concentration of DPC and in the presence of the ligand (R)-PK11195, that stiffens it significantly. In the absence of ligand, the structure of mTSPO is too flexible to be resolved by NMR. Furthermore, to date, no amphiphilic condition has allowed the crystallization of mammalian TSPOs, with and without ligand, unlike bacterial TSPOs.The aim of the present study is to determine, using a structure/function approach, the effect of different amphiphilic environments on the structure of apo-mTSPO (i.e. without the ligand). We investigated mTSPO's structure in solution at different scales using radiation scattering and optical spectroscopy techniques. Small-angle X-ray and neutron scattering (SAXS, SANS), combined with size-exclusion chromatography (SEC), contrast variation in SANS, and ab initio modeling, allowed us to obtain the conformation of the entire mTSPO/amphiphile complex and to specifically probe those of the protein and the amphiphilic belt within the complex. The quantity of amphiphile molecules associated with mTSPO, measured by MALS, allowed the validation of the proposed models. The effect of the environment on ligand affinity was measured by microscale thermophoresis (MST).The apo-mTSPO, produced by a recombinant way in E.coli bacteria inclusion bodies, is partially unfolded following its extraction by SDS. We show that the protein refolds in DPC, both locally (significant increase of content and interactions of α-helices and in tryptophan fluorescence) and three-dimensionally, with a more extended "apo" conformation than the NMR structure 2MGY.PDB. Adding DMPC phospholipids to create a partially biomimetic environment of mixed DMPC:DPC bicelles further structures apo-mTSPO: the quantity and interactions of α-helices, as well as tryptophan fluorescence, increase significantly. This refolding is associated with a significant increase in the protein's affinity for the ligand (R)-PK11195 (0.9 μM) compared to that in DPC (70 μM) and SDS (no affinity). Thus, we demonstrate the relevance of using DMPC:DPC bicelles for studying membrane proteins in solution and confirm the crucial role of lipids in the structure and function of mTSPO. Finally, we show that this environment is favorable for the crystallization of apo-mTSPO and for reconstituting the protein in DMPC nanodiscs.To compare these results with a protein expressed under native conditions, we developed a new protocol for producing mTSPO in yeast cells. We managed to purify the protein in “apo” condition in DDM, a detergent known for solubilizing properly folded proteins, while retaining associated membrane lipids.This thesis work (i) contributes to a better understanding of the structure/function of mTSPO in different amphiphilic environments to determine optimal conditions for higher-resolution structural studies, and (ii) provides a significant methodological contribution to the study of membrane proteins in solution
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Alarcon, Jean-Luc Bruno. "Emerging Capabilities and Firm Performance in the Cloud Computing Environment." Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/493895.
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Business Administration/Interdisciplinary<br>D.B.A.<br>New capabilities required to succeed in the new Cloud environment represent a radical change for software companies, which have to transition from selling on-the-premises software products to providing subscription-based cloud services (aka Software-as-a-Service or SaaS). While emerging SaaS vendors have led the exponential growth of the market, the traditional software industry has been disrupted. The purpose of this dissertation is to analyze which capabilities are driving the performance of software firms in today’s cloud-computing environment by drawing upon the resource-based view (RBV) of the firm. What is the optimum spending across the primary firm capabilities (e.g., service delivery, R&D, marketing and sales) to maximize financial performance? This dissertation focuses on publicly-traded SaaS companies using publicly-available information from financial databases, corporate investor relations materials, and industry research. It is comprised of two essays. The first essay is a quantitative study based on secondary data. The second essay includes an extensive literature review, an analysis of in-depth interviews of practitioners, and mini case studies. Together, the essays contribute to RBV theory and provide useful insights to help assess the quality of execution of SaaS growth strategies and improve financial planning and performance in the software industry for the cloud computing environment. Although the results come from firms in the SaaS industry, the findings from this study could cautiously generalize to firms in other emerging technology industries. The dissertation concludes with a detailed agenda for future research.<br>Temple University--Theses
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Erkan, Berna. "The Role Of Sais In Promoting Sustainable Development: Environmental Auditing." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12613993/index.pdf.
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This thesis is based on cross-sectional data analyses by using Ordinary Least Squares (OLS) Method in order to determine the main drivers of the environmental performance and specifically the effects of environmental audits conducted by
Supreme Audit Institutions (SAIs) on sustainable development. Two general models are employed throughout the study that have the Environmental Performance Index
(EPI) as dependent variable and various sub-models for different income groups are produced to observe the individual and interactive effects of explanatory variables.
First model includes 150 countries regressing their EPI scores on income, population, literacy rate and indicators of the strength of institutional structure such as corruption
perceptions index or government effectiveness score. Then, second model which comprises 52 countries introduces the number of environmental audit reports as a new explanatory variable. Principal Component Analysis (PCA) is also applied to highly correlated variables and the models are reestimated. The results indicate that well functioning environmental management systems and resulting positive effects on
the environmental performance can only be attained through strengthened governmental institutions with high transparency and accountability as well as rigid
implementation of the related regulations. More specifically, environmental audit reports generated by SAIs are of vital importance for especially improving the environmental management systems of the developing countries.
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Morrice, Jessica Rebecca Marie. "Modeling sporadic amyotrophic lateral sclerosis (sals) in zebrafish using environmental stressors." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62666.
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Amyotrophic lateral sclerosis (ALS) is characterized by the progressive degeneration of upper and lower motor neurons. The majority of ALS patients are considered of unknown origin, termed sporadic, and are largely assumed to arise from environmental insults. Despite this, research to date has been heavily focused on genetic models of the disease, which represent 10% of ALS cases. Research has made disappointing progress with elucidating disease initiating mechanisms and therapeutic translation in patients. Sporadic ALS (sALS) models may provide substantially more applicable insight into disease pathogenesis, however there is currently a lack of reliable and effective models. Zebrafish offer promising advantages to investigating ALS, with highly conserved biological processes to humans, including genes implicated in human neurodegenerative diseases. Further, they can be used for high throughput toxicity screening and are optically transparent as embryos to allow for high resolution imaging in vivo. Here, we investigate using zebrafish as a model for screening for motor neuron defects and hypothesize that exposure to particular environmental toxins can be used to induce ALS-like hallmarks in a zebrafish model. We find that the zebrafish is an efficient and effective model for screening motor neuron toxicity induced by neurotoxins and Bisphenol A (BPA) exposure has a clear dose-response effect on reduced motor neuron length and branching in embryos at 48 hours post fertilization (hpf). We provide evidence that motor axon length as a valid surrogate marker of motor neuron degeneration by confirming the conventional method of measuring the length from a sagittal view in defective motor axons represents their true length in 3 dimensions, and confirm that reduced motor axon length is associated with increased motor neuron death. Further, BPA exposure results in an ALS-like phenotype with reduced motor function at 24 and 48 hpf, reduced neuromuscular junction integrity and microglia activation in embryos at 48 hpf. Together, these results show that the zebrafish model is advantageous for screening toxin-induced motor neuron death and can be used as a valid model of sALS. This research can be extended to confirm ALS-associated neurotoxins and provide insight into pathogenic mechanisms of sALS.<br>Graduate and Postdoctoral Studies<br>Graduate
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Renninger, Nicole. "Indoor dust as a matrix for surveillance of COVID-19 outbreaks." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1619174839616049.
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Santana, Elaine Gonçalves Ferreira. "Conforto térmico e concentração de CO2 em salas de cirurgias e salas de espera para pacientes, climatizadas artificialmente." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/3/3146/tde-24122013-115533/.
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Nos últimos anos tem havido um aumento no estudo da qualidade do ar interno relacionado aos sistemas de ventilação mecânica e condicionamento do ar. Isso é especialmente fundamental em hospitais, onde a transmissão da contaminação pelo ar é considerada uma das principais causas de aquisição de doenças por pacientes, profissionais de saúde e visitantes. Além disso, essas instituições por abrigarem diversos setores, cada um com uma especificidade e função, exigem diferentes condições de conforto ambiental, sob os aspectos higrotérmico e de qualidade do ar, além do acústico e luminoso. Com o objetivo de avaliar a qualidade o ar, sob os parâmetros de conforto térmico e da concentração de dióxido de carbono em ambientes hospitalares climatizados artificialmente, realizou-se uma investigação de campo em salas de espera e salas de cirurgias de uma amostra de seis edifícios hospitalares na cidade de São Paulo e região metropolitana. Para coleta dos dados foram utilizados instrumentos de monitoramento, portáteis e de elevada precisão, adequados para a realização da pesquisa. Os resultados obtidos a partir da análise desses dados apontaram relevantes problemas relacionados ao conforto e a qualidade do ar. Dentre esses problemas, destacam-se a ausência de controle do diferencial de pressão entre as salas de cirurgias e os corredores; a divergência entre as temperaturas operativas ideais para promoção do conforto térmico para grupos de pessoas com diferentes vestimentas e nível de atividade, ocupando um mesmo ambiente, no caso, as salas de cirurgias; a insuficiência de renovação de ar, especialmente nas salas de espera equipadas com o sistema de climatização do tipo split-system; além da ausência de padronização entre os critérios dos referenciais técnicos mais adotados. Sob esses aspectos, percebeu-se a necessidade de melhoria do conhecimento da interação entre os ocupantes e o ambiente, especialmente naqueles onde o controle se faz necessário para a promoção da saúde.<br>In recent years has been increased interest in thermal comfort and air quality of indoor environments related to mechanical ventilation systems and air conditioning. This is especially crucial in hospitals where contaminated air transmission is considered a major cause of acquiring disease for patients, health care professionals and visitors. Moreover, these institutions having different sectors, each one with a speciality and function, require different conditions of environmental comfort, in terms of hygrothermal, air quality, acoustic and luminous aspects. In order to evaluate the air quality under the parameters of thermal comfort and carbon dioxide concentration in air conditioning hospital environments, it was carried out a field investigation in waiting rooms and operating rooms in six hospitals in São Paulo and metropolitan region. For data collection were used portable monitoring devices, suitable for research. The results from data analysis indicated significant problems related to thermal comfort and indoor air quality. Among these problems, it can be highlighted the lack of the differential pressure control between the operating rooms and corridors; the divergence among the optimal operative temperatures to provide thermal comfort for different groups of people with different clothing and activity level, occupying the same environment, in this case, the operating rooms; the disregard with the air changes required, especially in waiting rooms equipped with the splitsystem; besides the lack of standardization among the technical references criteria often used. Under these aspects, it is necessary to improve the knowledge of the interaction between the occupants and the environment, especially where the environmental control is decisive to promote the health.
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Fagrell, Mimmi. "Evaluation and development of environmental aspects and objectives at Saab Training Systems, Huskvarna." Thesis, Linnéuniversitetet, Institutionen för naturvetenskap, NV, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-13122.
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The purpose of this project work is to evaluate and update Saab Training Systems’ environmental objectives and to propose recommendations for its continuing environmental work. Since the company is ISO 14001 certified the work is based on that standard. To be able to update the objectives and propose new ones; the environmental aspects where first updated. The results of the work are; an evaluation of the company’s current environmental objectives, new environmental aspects, new environmental objectives and some suggestions for its continual environmental work. The results follow the current aspects and objectives when it comes to disposition but the content is updated. The company does not have industrial manufacturing or other activities that is usually associated with environmental impact but it still affects the environment in many ways. The many differences and additions the results show compared to the company’s own aspects and objectives show that it can be a good thing to look at things from a new perspective.<br>Syftet med det här examensarbetet är att utvärdera och uppdatera Saab Training Systems miljömål samt att ge förslag för det fortsatta miljöarbetet. Företaget är ISO 14001 certifierat och arbetet bygger därför på den standarden. För att kunna uppdatera de befintliga miljömålen och föreslå nya uppdaterades först miljöaspekterna. Resultatet av arbetet är; en utvärdering av företagets nuvarande miljömål, nya miljöaspekter, nya miljömål samt vissa förslag för det fortsatta miljöarbetet. Resultaten följer de befintliga aspekterna och målen när det gäller disposition men innehållet är uppdaterat. Företaget bedriver ingen industriell tillverkning eller har någon annan verksamhet som vanligtvis förknippas med miljöpåverkan men det påverkar ändå miljön på många sätt. De många olikheter och tillägg resultatet visar jämfört med företagets egna aspekter och mål visar att det kan vara bra att se på saker från ett nytt perspektiv.
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Štangl, Rastislav. "Procurement application solutions in cloud environment, evolution and trends." Master's thesis, Vysoká škola ekonomická v Praze, 2013. http://www.nusl.cz/ntk/nusl-199230.
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The goal of the presented thesis is to screen market and to assess the Procurement application solutions provided in cloud with focus on SMB companies. Understanding of Procurement process is base for identification of key functions and requirements on Procurement applications. Market research results in initial high level picture about the Procurement applications available with attention to cloud. Procurement applications assessment determines conclusions on market evolution and trends. The first part of the thesis introduces theoretical background of Procurement process and cloud computing. This part is completed by the list of key functions and requirements, of expected benefits, and of the steps that are important during assessment and selection of Procurement application in business. The second part investigates the Procurement application market and vendors. The screening is oriented on application features, client set, delivery models, and on other characteristics. Eight Procurement application solutions were selected for detailed assessment: Bellwether ePMX, Compleat Spend Control, Coupa, eBid eXchange, Ion Wave Technologies, PurchaseControl, Trade Interchange (ARCUS), and Xtenza. Assessment of the applications results in comparative data that are presented in predefined structure. The primary focus is on application features and Procurement functions supported. Other important evaluation categories are delivery models, security, underlying infrastructure, approval workflows, and commercials. Communication with application vendors contributed to the assessment. This part is finalized with evolution and trend conclusions focusing on cloud proliferation dynamics, and on forecast of new application functions and features that will result in new business benefits.
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Schwartz, Gerrit Jacobus. "The reconstruction of the identity of police trainers in a changing work environment." University of the Western Cape, 2016. http://hdl.handle.net/11394/5101.
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Magister Educationis (Adult Learning and Global Change) - MEd(AL)<br>This study set out to determine how trainers construct their professional identities in a changing work environment in a training academy of the South African Police Service (SAPS) in the context of a police-university partnership. The study differentiates between three professional identities (academic, police and trainer) and builds on the notion that the construction of professional identity is a conscious and dynamic process, which is formed in social contexts and settings where individuals participate in communities of practice or act on affordances to participate in organisational activities. Following a constructivist methodological approach, the study involved face-to-face interviews with trainers of the SAPS Academy and an analysis of police documents in the Academy. The study portrays trainers’ professional identity construction as relational and ongoing. Trainers perceive their changing roles in the SAPS Academy as a form of progression in their professional identity where one aspires to become an academic as a form of achievement. While the SAPS Academy attempts toregulate the construction of professional identity through enforcement of policies, it strengthens police trainer identities rather than enabling the construction of the needed new academic identities. Trainers therefore have to navigate the tensions between the institutional culture and construction of professional identity. Trainers negotiate their professional identities when they become part of the trainer pool, where they join smaller communities of practice, and when they make use of affordances for learning and development. The practice of multi-skilling of trainers, an authoritarian institutional culture and challenges to academic freedom and autonomy hamper their attempts to construct academic identities at both institutional and disciplinary level. The study suggests that organisations need to understand how policies contribute to employees’ construction of professional identities, particularly when new and unfamiliar professional identities are to be constructed. Development of higher academic qualifications is not enough. Workplaces need to apply organisational policies consistently and without ambiguity. A holistic approach should be followed when organisations embark on the construction of professional academic identities as employees construct professional identities through their lived experiences. Finally, the study showed that workplaces should provide a suitable environment that would stimulate professional and academic identity construction.
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Wei, Yulong. "Microbes Carry Distinct Genomic Signatures in Adaptation to Their Translation Machinery and Host Environments." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42422.
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How do bacteria grow and replicate rapidly? How do viruses and phages adapt to their host environments? Bacteria require efficient translation to grow and replicate rapidly, and translation is often rate-limited by initiation. A feature that is conserved across bacterial lineages is the Shine-Dalgarno (SD) sequence at the mRNA 5’ UTR, which pairs with the anti-SD sequence located at the 3’ end of mature 16S rRNA. Nonetheless, much about this interaction remains unclear. Chapter 2 reveals evolutionary differences between Cyanobacteria and chloroplast translation initiation using a new model (DtoStart) that better define optimal SD sequence and an RNA-Seq-based approach that reliably characterize the 3’ end of mature 16S rRNAs. Efficacy of translation elongation depends much on tRNA-mediated codon adaptation. In Escherichia coli, selection favours major codons because they are rapidly decoded by abundantly available cognate tRNAs. Nonetheless, the degree codon bias correlates with tRNA availability is unclear in many bacterial species because tRNA abundance is often inadequately approximated by gene copy numbers. To better understand tRNA-mediated codon bias, Chapter 3 describes an RNA-Seq-based approach to robustly quantify tRNA abundance. Finally, Chapter 4 evaluates the degree optimal translation initiation and elongation signals affect ribosome dynamics. The emergence of COVID-19 pandemic poses a serious global health emergency. To establish infection during cell entry, the coronavirus Spike protein binds to the host ACE2 receptor, and a high binding potential between these two players is key to infectivity. While SARS-CoV-2 transmits efficiently in humans, it is less clear which other mammals are at risk of being infected. Chapter 5 investigates the host range of SARS-CoV-2 through comparative sequence analyses at the ACE2 receptors and the Spike proteins. As obligate parasites, coronaviruses regularly infect host tissues that express antiviral proteins (AVPs) in abundance and must evade or adapt to the host cellular environments post-entry. Two AVPs that shape viral genomes are ZAP that binds to CpG dinucleotides to facilitate viral transcript degradation, and APOBEC3 which deaminates C into U leading to dysfunctional transcripts. Chapter 6 shows that coronavirus genomes are CpG deficient to evade ZAP and are subjected to constant C to U deamination by APOBEC3. This thesis examines two key concepts of microbial genome evolution: 1) coevolution between gene features and the translation machinery in bacteria, and 2) adaptation of viruses to the hosts they infect. Chapters 2, 3, and 4 are aimed at improving our understanding in bacterial gene expression in the applications of transgenic biosynthesis and phage therapy. Chapters 5 and 6 are aimed at improving our understanding in the origin and evolution of SARS-CoV-2 and our ability to control the spread of infection.
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Liang, Yan-Mei (AMY). "The Determinants of Customer Perceptions in a Dynamic Business Environment: An Exploratory Analysis of the ASP Business Model." The University of Waikato, 2008. http://hdl.handle.net/10289/2555.
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Outsourcing attracted much attention in 1989 when Kodak outsourced its data center operation to IBM (International Business Machines Corp.). Nowadays, this strategy has become more popular. At the beginning of this century, the ASP (Application Service Provider) model was considered one of the typical solutions of Internet-based IT (Information Technology) outsourcing. Although this model has been transformed and renamed (e.g. SaaS - Software as a Service), the principle concept of providing IT service through the Internet or wide area network is still there. This study attempts to explore the determinants of customer perception of Internet-based IT outsourcing by obtaining a comprehensive understanding of the ASP model. The research dimensions not only include factors affecting users' perception of service quality but also ASP business position (i.e. the firm origin of ASP and its provider type) and services utilized by the customers. Through the study of firm history, two important theoretical themes of this research - path-dependence and Ansoff's product/ market growth matrix - are taken account of in exploring the influence of the determinants. Web-based questionnaire survey research is conducted together with a documentation study to collect data. Targeting the customers of the top 50 ASPs selected by ASPnews.com during the period 2001-2004, the researcher contacted 597 potential respondents, and 196 responses were returned. The valid sample consisted of 175 responses, and 124 of them not only provided full information for satisfaction evaluation but also the information for tracking their ASP vendors' business position. The GLM (General Linear Model) and the Pearson correlation coefficient were the major statistical approaches used to evaluate the survey data for developing a structural model. The research findings indicated that the factors associated with service competitiveness, such as capability and performance, reliability and trustworthiness, affordability, integration and customization, have positive effects on customer perceived satisfaction; whereas lock-in has a negative effect. More specifically, the origin of the ASP firm has a direct effect on capacity and performance, and also directly influences the use of IT adoption services. Based on this finding, a descriptive analysis and qualitative research shows that two mechanisms for path-dependence - existing expertise and perceived expertise - can affect the satisfaction level of capacity and performance of ASP services. On the other hand, provider type has a direct effect on affordability and also directly influences the use of facility supporting services. On this basis, another two mechanisms for path-dependence - transaction cost and standardization - can indirectly impact customer's perception of this business model via affordability. In addition to those major findings, some other determinants (e.g. software applications, brand of applications, and intensity of service used) were also identified in this study. The study result can be used for theoretical understanding about the determinants of ASP customer's perception. It not only indicates a new perspective to enhance the current body of research on this topic, but can also be more broadly applied to any fast-growth firm, rapid-change business, or technology intensive industry. Acknowledgements I would like to sincerely thank the following people for their contribution to this research project. Dr. Scott Koslow, my chief supervisor, for his continued encouragement, patience and guidance to ensure the completion of this project. His speciality in statistics has provided appropriate and valuable guidance in the data analysis for my research. Dr. Steven Lim, my second supervisor, for his advice, coherence, and support over the years. I also appreciate his constructive comments on my drafts and the shaping of my research. Dr. Bob McQueen and Dr. Jim Corner, for their assistance and advice in the early stages of my study. My parents, Yu-Ho and Lee-Chiung Liang, and my brother Ken, my sisters Annie, Eva, and Nancy, my brothers-in-law, J.C. and Chen, and Alice, my sister-in-law, for their emotional support throughout the length of my study. I also thank Bessie, my best friend for her assistance in data collection and her loving support, as well as Ted, Kevin, Mark, Frank, and Shirley, my study mates for their encouragement and friendship. Special thanks goes to Dr. Kuang-Ya Wang, the principal of Yu Da High School of Commerce and Home Economics, Taiwan, and also to the staff over there for their concern and assistance in data collection. Most importantly, my heartfelt appreciation goes to Warren, my husband. I am deeply grateful to him for his understanding, patience, and practical help. Without his enduring support I could not have done this study. Finally, my thanks and gratitude goes to those people who patiently answered my survey questionnaire as their kind assistance made it possible to complete this research.
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Chevrollier, Nicolas. "Coexistence and call admission control in a heterogeneous wireless environment." Evry, Institut national des télécommunications, 2006. http://www.theses.fr/2006TELE0011.
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In today’s digital world, various types of users, applications and wireless technologies interact to create a complex and heterogeneous environment. In this thesis, we address two issues introduced by the heterogeneity of the digital world. First, we evaluate the interference generated when multiple wireless technologies operate in close proximity. We develop two coexistence mechanisms to mitigate interference in the 2. 4 GHz frequency band: a scheduling scheme for Bluetooth devices known as bluetooth interference aware scheduling and a scheme based on Layer 2 triggered handovers. Second, we investigate how to integrate vertical handovers into call admission control algorithms in order to limit the communication disruption and quality of service discontinuity. We evaluate the impacts of those handovers in terms of packet loss and disruption latency, and develop two call admission control algorithms, namely the probabilistic call admission control and handover-based call admission control algorithms. The former is based on a probabilistic admission decision and the latter includes a bandwidth reservation policy along with preemptive handovers. Both aim at reducing the occurrence of hard handovers in a heterogeneous wireless environment<br>Dans le monde digital qui nous entoure, différents types d'utilisateurs, d'applications et de technologies sans fil interagissent pour créer un environnement complexe et hétérogène. Le travail effectué dans cette thèse traite de problématiques introduites par le caractère hétérogène du monde digital. Le premier sujet d'étude s'attache à évaluer les interférences générées dans le bande de fréquence 2. 4 GHz lorsque plusieurs technologies sans fil opèrent en même temps dans un espace limité. Deux solutions sont proposées pour réduire ou éviter ces interférences. La première est un mécanisme d'ordonnancement des paquets au niveau de la couche MAC Bluetooth. La deuxième utilise des passages inter ou intra technologie déclenchés par des indicateurs de niveau 2. Le deuxième sujet d'étude s'attarde sur la mobilité verticale dans un environnement sans fil hétérogène. Les effets de cette mobilité sont évaluées sur le flux applicatif et la discontinuité de qualité de service que ces passages introduisent est analysée. Par la suite, deux algorithmes de contrôle d'admission qui prennent en compte le caractère néfaste de certains passages entre technologies sont proposés. Flexible et robuste, le premier repose sur une décision probabilistique d'admission dans une cellule WLAN. Le second utilise un système de réservation pondéré de bande passante et des passages préemptifs pour diminuer les nombres de passages de type "hard" et améliorer la qualité de service perçue par les utilisateurs
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Soua, Ridha. "Wireless sensor networks in industrial environment : energy efficiency, delay and scalability." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-00978887.
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Some industrial applications require deterministic and bounded gathering delays. We focus on the joint time slots and channel assignment that minimizes the time of data collection and provides conflict-free schedules. This assignment allows nodes to sleep in any slot where they are not involved in transmissions. Hence, these schedules save the energy budjet of sensors. We calculate the minimum number of time slots needed to complete raw data convergecast for a sink equipped with multiple radio interfaces and heterogeneous nodes traffic. We also give optimal schedules that achieve the optimal bounds. We then propose MODESA, a centralized joint slots and channels assignment algorithm. We prove the optimality of MODESA in specific topologies. Through simulations, we show that MODESA is better than TMCP, a centralized subtree based scheduling algorithm. We improve MODESA with different strategies for channels allocation. In addition, we show that the use of a multi-path routing reduces the time of data collection .Nevertheless, the joint time slot and channels assignment must be able to adapt to changing traffic demands of the nodes ( alarms, additional requests for temporary traffic ) . We propose AMSA , an adaptive joint time slots and channel assignment based on incremental technical solution. To address the issue of scalability, we propose, WAVE, a distributed scheduling algorithm for convergecat that operates in centralized or distributed mode. We show the equivalence of schedules provided by the two modes.
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Rees, Simon William. "The control of oogenesis in Nereis (Neanthes) virens (SARS) : interactions of environmental and endogenous mechanisms." Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242375.
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Albuquerque, José Alfredo de. "Avaliação do passivo ambiental de solos degradados por sais no perímetro irrigado Curu Pentecoste, Ceará." reponame:Repositório Institucional da UFC, 2015. http://www.repositorio.ufc.br/handle/riufc/18982.
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ALBUQUERQUE, José Alfredo de. Avaliação do passivo ambiental de solos degradados por sais no perímetro irrigado Curu Pentecoste, Ceará. 2015. 82 f. : Tese (doutorado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia Agrícola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2015.<br>Submitted by demia Maia (demiamlm@gmail.com) on 2016-08-08T15:40:50Z
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Previous issue date: 2015<br>The research has as a physical basis the Curu Pentecoste Irrigated Perimeter, under jurisdiction of the Departamento Nacional de Obras Contra as Secas (National Department of Works to Combat Drought) and as an objective quantify the extent, the cost of reversal and legal responsibility for the environmental liability. The public irrigation in the Brazilian semi-arid has generated salt-induced soil degradation as a by-product, originating a legal liability, and its legal responsibility lies with the state authority. To quantify the extent and cost of reverting the environmental damage, initially, a survey was conducted among irrigating farmers to analyze the meaning they give to the problems related to the irrigation, the water used in irrigation and the degradation of the soil. Beforehand an electromagnetic induction sensor was used to measure the electrical conductivity in the soil, estimating the total of soluble salts in its solution. The electrical conductivity values obtained by the sensor oriented the collection of soil samples for the purposes of physical and chemical analyses, proceeding to the identification of the areas degraded by salt. With the definition of the extent of the environmental damage, the values of the main crops and the gross value of the agricultural production were collected to assess the costs of reverting the environmental liability. The results showed financial and technical insufficiencies of the irrigating farmers; that the environmental degradation by salt reaches 67,27% of the irrigated perimeter. In conclusion, as a result of the solidarity aspects, the strict civil liability in repairing the environmental damage caused by irrigation lies with the state authority.<br>A pesquisa tem como base física o Perímetro Irrigado Curu Pentecoste, jurisdicionado ao Departamento Nacional de Obras Contra as Secas, e como objetivo geral quantificar a extensão, o custo da reversão e a responsabilidade legal pelo passivo ambiental. A irrigação pública no semiárido brasileiro tem gerado como subproduto a degradação dos solos por sais, formando um passivo ambiental, cuja responsabilidade legal da reversão é do poder público. Para quantificar a extensão e o custo da reversão do dano ambiental, inicialmente, aplicou-se um questionário aos agricultores irrigantes para analisar o significado que eles dão aos problemas relacionados com a irrigação, com a água de irrigação e com a degradação dos solos. Posteriormente, utilizou-se um sensor de indução eletromagnética para medir a condutividade elétrica no solo, estimando-se o total de sais solúveis em sua solução. Os valores da condutividade elétrica aferidos pelo sensor nortearam a coleta de amostras de solo para fins de análise física e química, procedendo-se à identificação das áreas degradadas por sais. Com a definição da extensão dos danos ambientais, levantaram-se os valores de produtividade das principais culturas e o valor bruto da produção agrícola, para aferir os custos da reversão do passivo ambiental. Os resultados demonstraram uma hipossuficiência financeira e técnica dos agricultores irrigantes; que a degradação ambiental por sais atinge 67,27% da área do perímetro irrigado. Conclui-se que, em decorrência dos aspectos de solidariedade, a responsabilidade civil objetiva na reparação do dano ambiental provocado pela irrigação é do poder público.
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Gorcitz, Raul Adrian. "From small-scale data dissemination to large data transfers in vehicular environments." Paris 6, 2013. http://www.theses.fr/2013PA066271.
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Les ve ́hicules de nos jours sont des syste`mes distribue ́s complexes qui entraˆıne l’e ́volution des exigences en matie`re de capacite ́s de re ́seau. L’e ́mergence de plusieurs applications a souligne ́ la ne ́cessite ́ pour les communications automobilesdans le ve ́hicule lui-m eˆme et ses environs. Celui-ci fait re ́fe ́rence a` la soi-disant paradigmes de communication ve ́hicule a` ve ́hicule (V2V) et ve ́hicule a` l’infrastruc- ture (V2I), qui ont pousse ́ a` l’adoption de technologies de re ́seau sans fil. L’inte ́r eˆt pour ces technologies a e ́te ́ en constante augmentation dans la dernie`re de ́cennie et montre un grand potentiel. Avec une demande croissante pour des capacite ́s de communication, l’industrie automobile revisite le r oˆle des ve ́hicules dans la vie des utilisateurs. La plupart des recherches sur les syste`mes de communication automobile a e ́te ́ encourage ́ par les exigences impose ́es par les applications allant de la gestion de la circulation a la se ́curite ́ routie`re. Cela a conduit a` l’e ́laboration d’un certain nombre d’initiatives dans le monde entier qui e ́tudient des solutions avec des implications importantes sur le processus de l’inge ́nierie automobile. Ces initiatives sont axe ́es sur l’e ́tablissement des normes dans des domaines tels que “suˆrete ́ et la se ́curite ́” ou “pilote de pointe”<br>As we have previously seen, vehicle-to-vehicle communication is an essential part of coop- erative driving as messages need to be disseminated over large interest areas with on-board communication devices. Vehicular networks are shared environments where each vehicle competes for a share of the bandwidth, thus when sending general purpose message that could potentially interest every driver in a certain area, broadcast-based communication is more adapted to the characteristics of this environment. Yet the role of the vehicle is expanding and is not limited to inter-vehicular communication. New functionalities are introduce that exploit the inherent properties of this environment. Although vehicles enjoy a high degree of freedom, their mobility can be predicted to a certain extent. Vehicles are generally restricted to the use of the road-infrastructure that links geographically distinct points of interests situated tens, hundreds or thousands of kilometers apart. They are fulfilling a purpose by carrying a ’load’ from a source to a destination. Therefore, the road-infrastructure is constituted of a network of intersecting roads on which transiting vehicles respond to the requirements of their owners. By taking advantage of these characteristics, new applications can be developed that exploit the technologies present in the modern car. We direct our attention towards the large volume of data that transit the internet everyday. A large part of this data tolerates a certain amount of delay before it is being ’consumed’. Disruptive solutions could ease the burden on the legacy internet infrastructure by considering vehicles as a future data delivery alternative
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Dechering, Matthew J. "Traffic Management of Small-Unmanned Aerial Systems in an Urban Environment." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1554216904089988.
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Chavez, Panduro Elvia Anabela. "Synchrotron Nano-scale X-ray studies of Materials in CO2 environment." Thesis, Le Mans, 2014. http://www.theses.fr/2014LEMA1010/document.
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Le travail qui est présenté dans ce manuscrit est le résultat d'une série d'expériences qui ont été effectuées à la fois à l'Université du Maine (IMMM Le Mans) et aux lignes de lumière lD10 et lD02 de l'ESRF (Grenoble) où j'ai passé la moitié de mon temps. Le projet que j'ai travaillé pendant trois ans a été principalement orienté sur l'étude des nanomatériaux qui ont été exposés au CO2 supercritique en utilisant de diffusion des rayons X. Par conséquent une partie de ce travail a été consacrée à la description des propriétés de ce fluide supercritique et comment il interagit avec des matériaux tels que les polymères par exemple. Les matériaux analysés ont été le polystyrène sous forme de film et des ilots, ensuite des matériaux meso-structures avec des tensioactifs fluorés et finalement le carbonate de calcium. Due à la taille nanométrique de tous ces matériaux, les techniques de rayons X qui ont été largement utilisés dans ce travail étaient Small angle X-ray scattering (SAXS), Grazing Small angle X-ray scattering ( (GISAXS) et X-ray reflectivity (XRR)<br>The work that is presented in this manuscript is the result of a series of experiments that were performed both at the Université du Maine (IMMM Le Mans) and at the ID10 and ID02 beam lines of the ESRF (Grenoble) where I have equally spent half of my time. The project I have been working on for three years was mostly oriented on the study by means of X-ray scattering probes of nanomaterials that were exposed to supercritical CO2. As a result another part of this work will be also dedicated to describing the properties of this supercritical fluid and how it interacts with materials such as polymers for instance. The analyzed materials were thin film and small island of polystyrene, then materials mesostructures using fluoro-surfactants and finally calcium carbonate. Due to the nanoscale of these materials, the X-ray probes that were extensively used in this work were Small Angle X-ray scattering (SAXS), Grazing Incidence Small Angle X-ray Scattering (GISAXS) and X-ray Reflectivity (XRR)
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Pereira, Rui Luís Alves. "Aromas nos cinemas : estudo exploratório do impacto de estímulos olfativos na perceção de qualidade e consumo de produtos em salas de cinema." Master's thesis, Instituto Superior de Economia e Gestão, 2012. http://hdl.handle.net/10400.5/10349.
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Mestrado em Marketing<br>Efetuou-se um estudo experimental em contexto real num cinema, com o objetivo de compreender se os estímulos aromáticos podem influenciar o comportamento do consumidor, testar se o aroma ambiente é, ou não, um instrumento de marketing eficaz. O estudo foi realizado através de uma investigação quantitativa entre a presença e ausência de aroma ambiente na aferição de respostas dos espetadores no seu ambiente de cinema. A Investigação teve por base a revisão da literatura, para o enquadramento do tema e desenvolvimento do modelo conceptual conducente à formulação da questão de pesquisa e das hipóteses a testar, tendo como alicerce a construção do questionário e desenho da experiência. A coleta dos dados foi efetuada durante quatro semanas e teve por base pesquisas similares. As análises dos dados recolhidos incluíram técnicas de estatística descritiva e teste das hipóteses relativas à avaliação do cinema, do seu ambiente, dos seus produtos, dos gastos e por último da intenção de retorno do espetador ao cinema. Foram identificadas relações de causa efeito na presença de aroma, os resultados revelaram que a presença de aroma ambiente aumentou as avaliações testadas.<br>A real life experimental study was conducted in a movie theatre in order to try to understand if the aromatic stimuli can influence consumer behavior, that way testing if the aroma present in the environment is an effective marketing tool. The study was a quantitative investigation of the answers given by spectators in the presence or absence of aroma in their cinema environment. The research was based on a literature revision, in order to develop both the guidelines and the conceptual model, which in turn led to the formulation of the research question and the definition of the hypothesis to be tested, which constitute the basis upon which the questionnaire and experience design were construed. The data collection was performed during a period of four weeks and based on a similar research. Data was analyzed using descriptive statistics and hypothesis testing on movie theatre, environment, product and cost evaluations and finally the intention of the spectator to return to the movie theatre. Cause and effect relations were identified in the presence of aroma. The results showed that the presence of aroma in the environment increased the evaluations tested.
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Soua, Ridha. "Wireless sensor networks in industrial environment : energy efficiency, delay and scalability." Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066029.
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Certaines applications industrielles nécessitent des délais de collecte déterministes et bornés, nous nous concentrons sur l'allocation conjointe de slots temporels et de canaux sans conflit qui minimisent la durée de collecte. Cette allocation permet aux noeuds de dormir dans n'importe quel slot où ils ne sont pas impliqués dans des transmissions. Nous calculons le nombre minimal de slots temporels nécessaire pour compléter la collecte de données brute pour un puits équipé de plusieurs interfaces radio et des demandes de trafic hétérogènes. Nous donnons également des ordonnancements optimaux qui permettent d'atteindre ces bornes optimales. Nous proposons ensuite MODESA, un algorithme centralisé d'allocation conjointe de slots et de canaux. Nous montrons l'optimalité de MODESA dans des topologies particulières. Par les simulations, nous montrons que MODESA surpasse TMCP , un ordonnancement centralisé à base de sous-arbre. Nous améliorons MODESA avec différentes stratégies d'allocation de canaux. En outre , nous montrons que le recours à un routage multi-chemins réduit le délai de collecte.Néanmoins, l'allocation conjointe de slot et de canaux doit être capable de s'adapter aux changements des demandes des noeuds (des alarmes, des demandes de trafic supplémentaires temporaires). Nous proposons AMSA , une solution d'assignation conjointe de slots et de canaux basée sur une technique incrémentale. Pour aborder la question du passage à l'échelle, nous proposons, WAVE , une solution d'allocation conjointe de slots et de canaux qui fonctionne en mode centralisé ou distribué. Nous montrons l'équivalence des ordonnancements fournis par les deux modes<br>Some industrial applications require deterministic and bounded gathering delays. We focus on the joint time slots and channel assignment that minimizes the time of data collection and provides conflict-free schedules. This assignment allows nodes to sleep in any slot where they are not involved in transmissions. Hence, these schedules save the energy budjet of sensors. We calculate the minimum number of time slots needed to complete raw data convergecast for a sink equipped with multiple radio interfaces and heterogeneous nodes traffic. We also give optimal schedules that achieve the optimal bounds. We then propose MODESA, a centralized joint slots and channels assignment algorithm. We prove the optimality of MODESA in specific topologies. Through simulations, we show that MODESA is better than TMCP, a centralized subtree based scheduling algorithm. We improve MODESA with different strategies for channels allocation. In addition, we show that the use of a multi-path routing reduces the time of data collection .Nevertheless, the joint time slot and channels assignment must be able to adapt to changing traffic demands of the nodes (alarms, additional requests for temporary traffic) . We propose AMSA , an adaptive joint time slots and channel assignment based on incremental technical solution. To address the issue of scalability, we propose, WAVE, a distributed scheduling algorithm for convergecat that operates in centralized or distributed mode. We show the equivalence of schedules provided by the two modes
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Gebremariam, Gebrelibanos [Verfasser]. "Sustainable Agricultural Practices (SAPs) in Northern Ghana : impacts on welfare, environmental reliance, and agricultural land expansion / Gebrelibanos Gebremariam." Bonn : Universitäts- und Landesbibliothek Bonn, 2018. http://d-nb.info/1170872298/34.
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Dabboussi, Abdallah. "Dependability approaches for mobile environment : Application on connected autonomous vehicles." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCA029.
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Les véhicules autonomes et connectés (VAC) doivent avoir une exigence de fiabilité et de sécurité adéquate dans un environnement incertain aux circonstances complexes. La technologie des capteurs, les actionneurs et l'intelligence artificielle (IA) améliorent constamment leurs performances, ce qui permet un développement continu des véhicules autonomes et une automatisation accrue de la tâche de conduite. Les VAC présentent de nombreux avantages dans la vie humaine, tels que l’augmentation de la sécurité routière, la réduction de la pollution et la fourniture d’une mobilité autonome aux non-conducteurs. Cependant, ces composants avancés créent un nouvel ensemble de défis en matière de sécurité et de fiabilité. Il est donc nécessaire d’évaluer ces technologies avant leur mise en œuvre.Nous étudions dans cette thèse la fiabilité du VAC dans son ensemble, en nous concentrant sur les capteurs et le système de communication. Pour cela, une analyse fonctionnelle a été réalisée pour le système VAC. Notre approche scientifique pour l'analyse de la fiabilité du VAC a été structurée avec des méthodes combinant des approches quantitatives et qualitatives (telles que l'analyse fonctionnelle interne et externe, l'analyse préliminaire des risques (APR) et l'analyse des modes de défaillance, de leurs effets et de leur criticité (AMDEC), etc. Afin de prouver nos résultats, une simulation a été réalisée à l'aide de la probabilité d'analyse d'arbre de défaillance (ADD) et elle a été réalisée pour valider l'approche proposée. Les données (taux d'échec) utilisées proviennent d'une base de données professionnelle concernant le type de composants présentés dans le système. À partir de ces données, un modèle probabiliste de dégradation a été proposé. Le calcul de probabilité a été effectué par rapport à un moment d'utilisation de référence. Par la suite, une analyse de sensibilité a été suggérée concernant les paramètres de fiabilité et des propositions de restructuration ont été élaborées pour les composants.CAV fournit des services de communication entre véhicules : véhicules à véhicules (V2V) ou avec infrastructures côté rue : véhicules à infrastructures (V2I). La technologie des “Communications dédiées à courte portée” (DSRC = Dedicated Short Range Communications) utilise plusieurs canaux pour fournir une variété d'applications de sécurité. Les applications de sécurité nécessitent des transmissions appropriées et fiables, tandis que les applications non liées à la sécurité exigent des performances et une vitesse élevée. Aujourd’hui, la diffusion de messages de sécurité de base (Basic safety message, BSM) est l’un des services fondamentaux des véhicules connectés. Pour cela, un modèle analytique destiné à évaluer la fiabilité des services de diffusion V2V relatifs à la sécurité basée sur IEEE 802.11 dans le système DSRC sur autoroute a été proposé. Enfin, une amélioration du modèle proposé a été faite afin d'accroître la fiabilité de la connexion V2V, en tenant compte de nombreux facteurs tels que la portée de transmission, la densité du véhicule, la distance de sécurité sur l'autoroute, le taux d'erreur de paquets, l'influence de bruit et les taux de défaillants pour les équipements de communications.L'évaluation de ces problèmes conduit à une analyse de sensibilité liée aux paramètres de fiabilité, ce qui contribue à davantage d'innovation dans les domaines de l'ingénierie automobile<br>Connected and Autonomous vehicles (CAV) must have adequate reliability and safety requirements in uncertain environments with complex circumstances. Sensor technology, actuators and artificial intelligence (AI) are constantly and rapidly evolving, thus enabling further development of self-driving vehicles, and increasing the automation of driving. CAV shows many benefits in human life such as increasing road safety, reducing pollution, and providing independent mobility to non-drivers. However, these advanced components create a new set of challenges concerning safety and dependability. Hence, it is necessary to evaluate these technologies before implementation.We study in this thesis the reliability of CAV as a whole, focusing on sensors and the communication system. For that purpose, a functional analysis was done for the CAV system.Our scientific approach for the analyzing the CAV reliability, was structured with methods that combine quantitative and qualitative approaches such as functional analysis for both internal and external, Preliminary Risk Analysis (PRA), and failure modes and effects criticality analysis (FMECA), in addition to other analysis techniques.To prove our results, a simulation was done using the Fault Tree analysis (FTA) probability in order to validate the proposed approach. The data (Failure ratio) used were from a professional database related to the type of components presented in the system. Using this data, a probabilistic model of degradation was proposed. A probability calculation was performed in relation to a reference time of use. Thereafter a sensitivity analysis was suggested concerning the reliability parameters and redesign proposals developed for the components.CAV provide several communication models: vehicles to vehicle (V2V), or with Road Side Infrastructure: vehicle to infrastructure (V2I). Dedicated Short Range Communication (DSRC) employs a multichannel approach to cater for a variety of safety and non-safety applications. Safety applications necessitate appropriate and reliable transmissions, while non-safety applications require performance and high speed. Broadcasting of Basic Safety Messages (BSM) is one of the fundamental services in today’s connected vehicles. For that, an analytical model to evaluate the reliability of IEEE 802.11 based V2V safety-related broadcast services in DSRC system on highway was proposed. Finally, an enhancement on the proposed model was made in order to increase the reliability of the V2V connection, taking into consideration many factors such as transmission range, vehicle density, and safety headway distance on highway, packet error rate, noise influence, and failures rates of communication equipment.Evaluating these problems leads to a sensitivity analysis related to reliability parameters, which helps further innovation in CAV and automobile engineering
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Moraes, Clélia Mendonça de. "Conforto térmico em salas de aula no Brasil = análise experimental e numérica." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263734.
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Orientadores: kamal Abdel Radi Ismail, Bjarne Wilkens Olesen<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica<br>Made available in DSpace on 2018-08-18T21:57:56Z (GMT). No. of bitstreams: 1
Moraes_CleliaMendoncade_D.pdf: 11219740 bytes, checksum: 58fccb247696bc4b704b7456032700a6 (MD5)
Previous issue date: 2009<br>Resumo: A qualidade da sala de aula é determinada pelo projeto da edificação. Esse, por sua vez, exerce uma forte influência sobre as condições térmicas do aluno em aula. A relevância de formularem-se normas e padrões específicos para esse tipo de ambiente que considere as suas particularidades é discutida em países como Dinamarca, Finlândia, Holanda, Suíça, Estados Unidos entre outros. No Brasil, como avaliação pós-ocupação. Sendo assim, a presente pesquisa avalia o comportamento térmico real em sala de aula com o levantamento de variáveis climatológicas do ambiente externo e interno da edificação localizada em duas universidades brasileiras no estado de São Paulo a fim de contribuir para o bem estar e produtividade. Por meio dos métodos de conforto térmico (Givoni, 1969) de ambientes envoltórios e sua correlação com a sensação térmica humana (Fanger, 1970) com a participação do aluno. Para estabelecer condições limite de conforto térmico em sala de aula, verificando as mudanças abruptas de temperatura em clima tropical de altitude. Adotou-se medida física objetiva e subjetiva. Monitoraram-se T(ºC), UR(%), Var(m/s) e P(atm); com o registro de dado interno por meio de "datalogger" e sensores; externo por Estação Meteorológica, e a percepção térmica do aluno foi avaliada com questionários. Aplicaram-se os dados obtidos no estudo do voto médio, ou seja, "CLO-FANGER-MET" interpolado com Givoni e nos softwares de simulação computacional de avaliação do desempenho ambiental de edificações. Os resultados finais obtidos com o cálculo numérico de sala de aula permitem obter uma avaliação de medidas padrões de uma temperatura ideal para salas de aula universitárias, estabelecendo o limite entre as zonas de conforto do metabolismo humano propondo um modelo adaptativo de conforto para um país com uma vasta variação latitudinal como o Brasil. Foi possível verificar através da análise da literatura que a qualidade do projeto da edificação determina a adaptação do homem ao clima<br>Abstract: The quality of the classroom is determined by edification Project. This exercise is a strong influence on the student's thermal conditions in classroom. The relevance of norms and specific patterns to the environmental that considers their particularities are discussed in countries such as Denmark, Finland, Holland, Switzerland, United States and among others. In Brazil, as post-occupation evaluation. In this manner, the research present evaluates the real thermal behavior in the classroom with the rising of climatology evaluation of external and internal environmental of the located edification in two Brazilian universities in the state of São Paulo in order to contribute to the comfort welfare and productive. Due to of thermal comfort methods (Givoni, 1969) of external environmental and his correlation with the human thermal sensation (Fanger, 1970) with the student's participation. Conditions establish limit of thermal comfort in classroom, verifying the abrupt changes of temperature in tropical climate of altitude. Physical measure was adopted aims at and subjective. Monitored T(ºC), UR (%), Var(m/s) and P(atm); with the registration of given internal through "datalogger" and sensor; external for Meteorological Station and the student's thermal perception was evaluated with questionnaires. The data were applied and obtained in the study of the medium vote, in other words, "CLO-FANGER-MET" interpolated with Givoni and in the softwares of computational simulation of evaluation of the environmental acting of constructions. The final results obtained with the numeric calculation of classroom allow to obtain an evaluation of measures patterns of an ideal temperature for university classrooms, establishing the limit between the areas of comfort of the human metabolism proposing a model comfort adaptation to a country with a vast latitudinal variation like Brazil. It was possible to verify through the analysis of the literature that the quality of the project of the construction determines the adaptation of the man to the climate<br>Doutorado<br>Termica e Fluidos<br>Doutor em Engenharia Mecânica
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Johansson, Henrik. "Sustainicle TM : How to Manage Sustainability within Product Development at Saab Automobile AB." Thesis, KTH, Miljöstrategisk analys, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-37606.
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Saab vehicles are recognised for being innovative, technically advanced, safe, with superior driving performance and with a characteristic design. Today the company has the broadest product portfolio ever. Saab has come to a point where there is a need for a strategic assessment of how to manage the environmental impacts and social concerns as well as to start earn profit to become a long term sustainable company. The Vehicle Development Process is the vital nerve when developing a new car and the Product Profile is the specification of requirements, it has today seven areas and sustainability could become the eight. The aim of this thesis is to identify and establish the most relevant sustainability areas and indicators within the Vehicle Development Process at Saab Automobile AB. These sustainability areas and indicators will be put into context to develop the overall sustainability within Saab Automobile. The research approach in this study is qualitative due to the fact that the information needed is difficult to quantify. To be able to obtain the needed information for this thesis a benchmarking study was made as well as interviews with experts besides the interviews within Saab Automobile. A disadvantage with the chosen method could be that the comparability with other studies decreases. It would probably be possible to use some of the findings within other companies. Today Saab Automobile has no published Sustainability Report, even though a small chapter is included in the Spyker Cars Annual Report. The main findings in this study are the sustainability areas and indicators. The five identified and established sustainability areas are; Design for Sustainability, Sustainable Supply Chain, CSR, Sustainable Innovation and Sustainable Value Chain. Also are 23 potential sustainability indicators proposed for Saab. The ambition to include these areas in the Product Profile is one step towards sustainability. This is still a limited approach that seems to be doing things right (efficiency) more than doing the right things (effectiveness). Based on the sustainability areas, indicators and the benchmarking study is a new sustainability strategy proposed for Saab.<br>Saabs bilar är igenkända för att vara innovativa, tekniskt avancerade, säkra, med överlägsna köregenskaper och ha en karismatisk design. Idag har företaget det bredaste produktsortimentet någonsin. Saab har nu nått en punkt då det krävs ett strategiskt ställningstagande för hur företaget skall hantera miljöpåverkan, sociala konsekvenser och samtidigt vara lönsamt för att bli ett långsiktigt hållbart företag. Produktutvecklingsprocessen är livsnerven då en ny bil skall tas fram och produktprofilen är en kravspecifikation, vilken idag består av sju olika områden och där hållbarhet skulle kunna bli det åttonde. Syftet med detta examensarbete är att identifiera och etablera de mest relevanta hållbarhetsområdena och indikatorerna inom produktutvecklingsprocessen vid Saab Automobile. Dessa hållbarhetsområden och indikatorer skall sättas in i sin kontext för att utveckla den övergripande hållbarheten inom Saab Automobile. Forskningsansatsen i detta examensarbete är kvalitativ baserat på det faktum att den nödvändiga informationen är svår att kvantifiera. För att kunna inhämta relevant information till denna undersökning har en benchmarkingstudie genomförts likväl som intervjuer med experter och anställda vid Saab Automobile. En nackdel med den valda metoden kan vara att jämförbarheten med andra undersökningar minskar. Det är troligt att det är möjligt att använda resultaten inom andra organisationer. Idag har Saab Automobile ingen publiserad hållbarhetsrapport, även om ett mindre kapitel är inkluderat i årsredovisningen för Spyker Cars. Huvudresultatet i denna undersökning är hållbarhetsområdena och indikatorerna. De fem identifierade och etablerade hållbarhetsområdena är; Design for Sustainability, Sustainable Supply Chain, CSR, Sustainable Innovation och Sustainable Value Chain. Samtidigt är 23 potentiella hållbarhetsindikatorer föreslagna till Saab. Ambitionen att inkludera hållbarhetsområdena i produktprofilen är ett steg mot hållbarhet, även om det är en begränsad ansats som verkar vara att göra saker rätt (eng. efficiency) mer än att göra rätt saker (eng. effectiveness). Baserat på hållbarhetsområdena, indikatorerna och benchmarkingresultaten är en ny hållbarhetsstrategi presenterad för Saab.
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Alam, Muhammad Mansoor. "Corrigé de localisation dans un environment extérieur sans fil en utilisant estimation, filtrage, la prévision et des techniques de fusion : une application par wifi utilisant le terrain à base de connaissances." Phd thesis, Université de La Rochelle, 2011. http://tel.archives-ouvertes.fr/tel-00815919.
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L'estimation de la position des noeuds de communication sans fil est un domaine de recherche très populaire au cours des dernières années. La recherche de l'estimation de l'emplacement n'est pas limitée à la communication par satellite, mais elle concerne aussi les réseaux WLAN, MANET, WSN et la communication cellulaire. En raison de la croissance et de l'évolution des architectures de communication cellulaire, l'utilisation des appareils portables a augmenté rapidement, et les appels provenant d'utilisateurs mobiles ont également rapidement augmenté. On estime que plus de 50% des appels d'urgence sont émis par des téléphones mobiles. Les chercheurs ont utilisé différentes techniques d'estimation de la position, tels que les satellites, les techniques statistiques et la cartographie. Afin d'atteindre une meilleure précision, certains chercheurs ont combiné deux ou plusieurs techniques. Cependant, l'estimation de la position basée sur le terrain est un domaine qui n'a pas été considéré en profondeur par les chercheurs. Grâce aux ondes radio qui se comportent différemment dans des atmosphères différentes, les calculs à l'aide de quelques paramètres ne sont pas suffisants pour atteindre une précision avec différents terrains, surtout quand il sont totalement basés sur le format RSS, qui entraine des altérations.Cette recherche se concentre sur la localisation des noeuds de communication sans fil en utilisant des techniques géométriques et statistiques, et en prenant en compte l'altération et l'atténuation des terrains. Le modèle proposé est constitué de quatre étapes, qui sont l'estimation, le filtrage, la prédiction et la fusion. Un prototype a été construit en utilisant le WiFi IEEE 802.11x standard. Dans la première étape, en utilisant le rapport signal-bruit de la zone géographique, la péninsule Malaisienne est classée en 13 types de terrains différents.Dans la deuxième étape, les points de données point-à-point sont enregistrés en utilisant la force du signal disponible et en recevant la puissance du signal en considérant différents types de terrains. L'estimation de la localisation se fait au cours de troisième étape en utilisant la célèbre méthode de triangulation. Les résultats estimés sont encore filtrés dans la quatrième étape en utilisant la moyenne et la moyenne des moyennes. Pour la correction des erreurs, le filtrage de l'emplacement est également fait en utilisant la règle des plus proches voisins. La prédiction est affinée au cours de la cinquième étape en utilisant la variance combinée qui permet de prédire la région considérée. L'utilisation des régions d'intérêt contribue à éliminer les emplacements situés à l'extérieur de la zone sélectionnée. Au cours de la sixième étape, les résultats du filtrage sont fusionnés avec la prédiction afin d'obtenir une meilleure précision.Les résultats montrent que les recherches effectuées permettent de réduire les erreurs de 18 m à 6 m dans des terrains fortement atténués, et de 3,5 m à 0,5 m dans des terrains faiblement atténués.
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Welsch, Bastian [Verfasser], Ingo [Akademischer Betreuer] Sass, and Liselotte [Akademischer Betreuer] Schebek. "Technical, Environmental and Economic Assessment of Medium Deep Borehole Thermal Energy Storage Systems / Bastian Welsch ; Ingo Sass, Liselotte Schebek." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2019. http://d-nb.info/1179361636/34.
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Berthou, Matthieu. "Fiabilité des assemblages sans plomb en environnement sévère." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2012. http://tel.archives-ouvertes.fr/tel-00991011.
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Le mémoire porte sur l'étude de la fiabilité des assemblages utilisant des alliages de brasure sans-plomb en environnement sévère pour des applications électroniques. Une méthode de préparation métallographique fiable et reproductible en vue de l'analyse microstructurale est présentée. L'effet du vieillissement thermique statique sur l'évolution microstructurale de billes de brasure en SAC, la tenue à la fatigue mécanique des assemblages brasés et l'étude de l'endommagement thermomécanique sont développés. Le seul effet notable constaté après vieillissement thermique est l'augmentation des épaisseurs des intermétalliques de contact. A la suite de sollicitations mécaniques, les ruptures sont plus souvent observées dans les pistes que dans les brasures, et ne permettent pas d'incriminer des éléments de la microstructure brasée comme facteurs déterminant de propagation des fissures. Les sollicitations thermomécaniques conduisent à une recristallisation, et les fissures se propagent alors le long des joints de grains recristallisés.
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Mhanna, Elissa. "Beyond gradients : zero-order approaches to optimization and learning in multi-agent environments." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASG123.
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L'essor des dispositifs connectés et des données qu'ils génèrent a stimulé le développement d'applications à grande échelle. Ces dispositifs forment des réseaux distribués avec un traitement de données décentralisé. À mesure que leur nombre augmente, des défis comme la surcharge de communication et les coûts computationnels se présentent, nécessitant des méthodes d'optimisation adaptées à des contraintes de ressources strictes, surtout lorsque les dérivées sont coûteuses ou indisponibles. Cette thèse se concentre sur les méthodes d'optimisation sans dérivées, qui sont idéales quand les dérivées des fonctions sont inaccessibles. Ces méthodes estiment les gradients à partir des évaluations de fonction, ce qui les rend adaptées à l'apprentissage distribué et fédéré, où les dispositifs collaborent pour résoudre des tâches d'optimisation avec peu d'informations et des données bruitées. Dans le premier chapitre, nous traitons de l'optimisation distribuée sans dérivées pour des fonctions fortement convexes sur plusieurs agents. Nous proposons un algorithme distribué de descente de gradient projete sans dérivées, qui utilise des estimations de gradient à un point, où la fonction est interrogée une seule fois par réalisation stochastique, et les évaluations sont bruitées. Ce chapitre démontre la convergence presque sûre de l'algorithme et fournit des bornes théoriques sur le taux de convergence. Avec des pas constants, l'algorithme atteint un taux de convergence linéaire. C'est la première fois que ce taux est établi pour des estimations de gradient à un point (voire même pour des estimations de gradient à deux points) pour des fonctions stochastiques. Nous analysons aussi les effets des pas décroissants, établissant un taux de convergence correspondant aux méthodes centralisées sans dérivées. Le deuxième chapitre se penche sur les défis de l'apprentissage fédéré qui est limité par le coût élevé de la transmission de données sur des réseaux à bande passante restreinte. Pour y répondre, nous proposons un nouvel algorithme qui réduit la surcharge de communication en utilisant des estimations de gradient à un point. Les dispositifs transmettent des valeurs scalaires plutôt que de grands vecteurs de gradient, réduisant ainsi la quantité de données envoyées. L'algorithme intègre aussi directement les perturbations des communications sans fil dans l'optimisation, éliminant le besoin de connaître explicitement l'état du canal. C'est la première approche à inclure les propriétés du canal sans fil dans un algorithme d'apprentissage, le rendant résilient aux problèmes de communication réels. Nous prouvons la convergence presque sûre de cette méthode dans des environnements non convexes et validons son efficacité à travers des expériences. Le dernier chapitre étend l'algorithme précédent au cas des estimations de gradient à deux points. Contrairement aux estimations à un point, les estimations à deux points interrogent la fonction deux fois, fournissant une approximation plus précise du gradient et améliorant le taux de convergence. Cette méthode conserve l'efficacité de communication des estimations à un point, avec uniquement des valeurs scalaires transmises, et assouplit l'hypothèse de bornitude de la fonction objective. Nous prouvons des taux de convergence linéaires pour des fonctions fortement convexes et lisses. Pour les problèmes non convexes, nous montrons une amélioration notable du taux de convergence, en particulier pour les fonctions dominées par le gradient K, atteignant également un taux linéaire. Nous fournissons aussi des résultats montrant l'efficacité de communication par rapport à d'autres techniques d'apprentissage fédéré<br>The rise of connected devices and the data they produce has driven the development of large-scale applications. These devices form distributed networks with decentralized data processing. As the number of devices grows, challenges like communication overhead and computational costs increase, requiring optimization methods that work under strict resource constraints, especially where derivatives are unavailable or costly. This thesis focuses on zero-order (ZO) optimization methods are ideal for scenarios where explicit function derivatives are inaccessible. ZO methods estimate gradients based only on function evaluations, making them highly suitable for distributed and federated learning environments where devices collaborate to solve global optimization tasks with limited information and noisy data. In the first chapter, we address distributed ZO optimization for strongly convex functions across multiple agents in a network. We propose a distributed zero-order projected gradient descent algorithm that uses one-point gradient estimates, where the function is queried only once per stochastic realization, and noisy function evaluations estimate the gradient. The chapter establishes the almost sure convergence of the algorithm and derives theoretical upper bounds on the convergence rate. With constant step sizes, the algorithm achieves a linear convergence rate. This is the first time this rate has been established for one-point (and even two-point) gradient estimates. We also analyze the effects of diminishing step sizes, establishing a convergence rate that matches centralized ZO methods' lower bounds. The second chapter addresses the challenges of federated learning (FL) which is often hindered by the communication bottleneck—the high cost of transmitting large amounts of data over limited-bandwidth networks. To address this, we propose a novel zero-order federated learning (ZOFL) algorithm that reduces communication overhead using one-point gradient estimates. Devices transmit scalar values instead of large gradient vectors, lowering the data sent over the network. Moreover, the algorithm incorporates wireless communication disturbances directly into the optimization process, eliminating the need for explicit knowledge of the channel state. This approach is the first to integrate wireless channel properties into a learning algorithm, making it resilient to real-world communication issues. We prove the almost sure convergence of this method in nonconvex optimization settings, establish its convergence rate, and validate its effectiveness through experiments. In the final chapter, we extend the ZOFL algorithm to include two-point gradient estimates. Unlike one-point estimates, which rely on a single function evaluation, two-point estimates query the function twice, providing a more accurate gradient approximation and enhancing the convergence rate. This method maintains the communication efficiency of one-point estimates, where only scalar values are transmitted, and relaxes the assumption that the objective function must be bounded. The chapter demonstrates that the proposed two-point ZO method achieves linear convergence rates for strongly convex and smooth objective functions. For nonconvex problems, the method shows improved convergence speed, particularly when the objective function is smooth and K-gradient-dominated, where a linear rate is also achieved. We also analyze the impact of constant versus diminishing step sizes and provide numerical results showing the method's communication efficiency compared to other federated learning techniques
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Chen, Yibo. "Routing algorithm dedicated to environmental data collection : precision agriculture." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22572/document.
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Les Réseaux de Capteurs Sans Fil (RCSF ou Wireless Sensor Network - WSN) sont l'une des technologies les plus importantes du 21ème siècle. La plupart des chercheurs et les analystes estiment que, dans un proche avenir, ces micro-capteurs seront intégrés partout dans l’environnement de notre vie quotidienne. Ces dernières années, l'Internet des Objets (Internet of Things - IoT) est également une des technologies émergentes qui se développe rapidement. Deux nouveaux standards permettent de déployer des réseaux sans fil de faible consommation énergétique connectés à internet : le protocole 6LowPAN (Low power Wireless Personal Area Networks) qui permet notamment d’apporter l’adressage IPv6 aux capteurs grâce à l’encapsulation et la compression des données et le protocole de routage RPL (IPv6 routing protocol for low-power and lossy network) qui permet à l’information de circuler dans les WSN de proche en proche à un faible coût énergétique. Bien que le développement de ces techniques soit extrêmement rapide, plusieurs problèmes causés principalement par le manque de ressources des micro-capteurs (puissance limitée de traitement, problèmes de bande passante et de connexion des liens avec perte de données, problème de ressource énergétique limitée) demeurent et doivent être résolus, notamment pour les applications agro-environnementales<br>The wireless sensor network (WSN) is one of the most important technologies of the 21st century. Most researchers and technical analysts believe that in the near future, these micro-sensors will be integrated into the environment of our daily lives. In recent years, the IoT (Internet of Things) and WoT (Web of Things) technologies also have great forwarding. Especially, the IPv6 over Low power Wireless Personal Area Networks (6LoWPAN) protocol has allowed the use of IPv6 protocol stack in the field of WSN, thanks to its encapsulation and compression mechanisms in IPv6 packet header. Moreover, the RPL (IPv6 Routing Protocol for Low-power and Lossy Network) provides such a powerful routing function that can be applied for a variety of application scenarios. These two key standards of IoT and WoT technologies for WSN can be used in an IPv6 stack, and they will successfully achieve the connection between Internet and micro-sensors. Thus, due to the availability of IPv6 address (128-bit), all the communicating objects, such as smart device, sensor, and actuator, can be connected to the Internet. That is the greatest advantage brought by the IoT. Although the progress of these techniques is extremely fast, several issues caused by resource constraints of micro-sensor (limited processing power, bandwidth and lossy connection link, and energy), such as QoS, energy efficient, robustness and lifetime of WSN, and the most important, the special requirement of agricultural applications. Notice that Precision Agriculture is are still very challenging and waiting to be solved. Essentially, these open questions would dabble in the aspects like telemedicine, remote home automation, industrial control etc. Thus, the results obtained in this work will have a significant impact on both economic and scientific. Economically, it can offer a solution for WSN to support sustainable development in the field of agriculture automation. While scientifically, we will contribute to the routing protocol standardization of wireless micro-sensors in the domain of environmental monitoring
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Chen, Ziyuan, and Zijun Liao. "The Connection Between External Environment and Internal Strategy : a case study of Scandinavian Airlines System." Thesis, University of Gävle, Department of Business Administration and Economics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-5835.
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<p>A variety of factors are the reasons for adjusting or changing company’s strategy, such as the change of customer demand, company’s internal financial factors, the influence of external environment and so on. This research is to find out the link between the change of external environment and the adjustment of internal strategy. Choose the suspension of one flight in SAS as the case to state this point. Show the strategy change of SAS when they were facing the serious impact of financial crisis.</p><p>SAS as the biggest airline in North Europe it could be a typical firm to investigate this kind of situation. A deep-interview and reading the published reports of SAS are the main data collection approached. Some resources were from the internet because it is real-time news and the reports from the company are published on their website. The interviewee is from the top of the company who is familiar this area and has full experience in international business. The study used lots of theories from different books and journals to integrate the information that we collected to analysis and achieve our final conclusion.</p><p>After analyzed the study it found the SAS used the retrenchment strategy as their new international strategy to reverse the negative situation. The financial crisis affected the customer demand badly not just in China also around the world and forced them to change the strategy. The report ultimate believed there were still a lot of other factors, beside the financial crisis, caused the adjustment of strategy in SAS.</p>
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Rahil, Ahmad. "Gestion du Handover dans les réseaux hétérogènes mobiles et sans fil." Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS006/document.
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Depuis les années 90, la technologie réseau et radio mobile a fait l'objet de progrès phénoménaux. Cette avancée technologique s'est faite en parallèle du côté réseau, du côté application et du coté besoin de l’utilisateur. L’évolution rapide de la technologie a eu pour conséquence l’existence d’un environnement hétérogène où la couverture est assurée par la coexistence de plusieurs types de réseaux. Le défi soulevé par cette architecture est de pouvoir naviguer entre plusieurs réseaux d’une façon transparente. La navigation entre réseaux de types différents est connue sous le nom du Handover vertical. Le standard IEEE 802.21 offre une composante appelée Media Independent Handover (MIH) qui contient une fonction capable de transmettre l’état des liens du nœud mobile depuis les couches inférieures vers les couches supérieures. MIH s’intercale entre le niveau 2 et le niveau 3 dans la pile protocolaire. Le rôle principal de MIH est d’aider le nœud mobile à faire un transfert sans coupure entre des réseaux de types différents, mais la logique de sélection est laissée sans implémentation.Dans ce contexte nous avons travaillé sur l’amélioration de la gestion du Handover en proposant une nouvelle architecture appelée VHMC et basée sur MIH offrant des nouvelles méthodes de sélection du réseau destination. La première proposition est un nouvel algorithme nommé Multiple Criteria Selection Algorithm (MCSA) basé sur plusieurs paramètres de qualité du service. Nous avons utilisé le simulateur Network Simulator (NS2) pour évaluer nos propositions en étudiant le nombre de paquets perdus et le temps de latence du Handover durant la période du transfert. La deuxième contribution est un nouveau modèle de sélection du réseau destination basé sur la technique de la logique floue. La base d’inférence, qui est l’élément central de la décision de ce modèle, est déduit grâce à une étude basée sur un nombre élevé de cas de Handover réels collectés des serveurs de la compagnie de télécommunication libanaise "Alfa". Une troisième solution est proposée à travers un nouveau modèle de sélection du réseau destination basé sur la théorie de la régression linéaire multiple<br>Since 1990, networking and mobile technologies have made a phenomenal unprecedented progress. This progress has been experienced on multiple fronts in parallel; especially on the application level and the user's needs one. This rapid evolution of the technology imposed a need for the existence of heterogeneous environments where the coverage is ensured throughout the different available networks. The challenge with such architecture would be to provide the user with the ability to navigate through the different available networks in a transparent and seamless fashion. However, the navigation among different types of networks is commonly referred to as vertical Handover. The IEEE 802.21 standard offers a component that is called Media Independent Handover (MIH) which has a function that provides the capability of transmitting the state of the connection of the mobile nodes from the lower to upper layers. This layer would exist between layer 2 and layer 3 within the protocol architecture. The main role of MIH is to help the mobile node transfer without interrupt among different types of networks, but the logic of selection is left without implementation. In this context, we worked on the improvement of the Handover management by proposing a new architecture, called VHMC and based on MIH by offering new methods for selecting the destination network. The first solution is a new algorithm called Multiple Criteria Selection Algorithm (MCSA) based on multiple parameters of the quality of service. We used Network Simulator (NS2) for testing our approach and study the number of lost packets and lost time during Handover. The second solution is a new model for selecting the destination network based on fuzzy logic techniques. The distinctive characteristic of this model lies in the study of genuine Handover records taken from a Lebanese mobile operator called "Alfa". A third proposed solution for network selection is based on multiple linear regression theory
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Johansson, Karin, and Emma Kotka. "“Your reason to fly is our reason to fly more sustainably” ...in an unsustainable environment : En kvalitativ visuell retorikanalys av flygbolaget SAS:s marknadskommunikation ur ett hållbarhetsperspektiv." Thesis, Högskolan för lärande och kommunikation, Jönköping University, HLK, Medie- och kommunikationsvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-47888.
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Följande studies syfte har varit att få en ökad förståelse för SAS:s marknadskommunikation, i relation till hållbarhet. Mer specifikt har SAS:s reklamfilmer studerats för att uppnå syftet. Metoden som har tillämpats för att uppnå detta är visuell retorikanalys. Den visuella retoriken har också inkluderats i det teoretiska ramverket. Teorin har kompletteras av bland annat traditionell retorik, CSR och etiskt ansvarstagande för att underlätta bearbetningen av det empiriska materialet i analysdelen. För att behandla empirin tillämpas också ett analysschema som ligger till grund för en systematisk analys och resultat. Analysschemat är baserat på frågor som är tagna ur teorin om visuell retorik. Resultaten av studiens analys påvisar att samtliga reklamfilmer innehåller många känslosamma retoriska argument. En annan del av resultatet har påvisat att SAS har utelämnat hållbarhetsaspekten i sin marknadskommunikation, bortsett från sin senaste reklamfilm. Slutsatser som dragits kring detta resultat är att det är problematiskt att SAS uppmanar allmänheten till att resa mer, trots den kritiska miljösituationen som råder i dagens samhälle.
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Deschamps, de Paillette Thierry. "Transmissions numériques sans-fil pour la surveillance environnementale en milieu sous-marin." Thesis, La Rochelle, 2020. http://www.theses.fr/2020LAROS023.
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La surveillance de l’environnement sous-marin nécessite le déploiement de capteurs et d’infrastructures dédiées dont le coût et l’impact sur la faune et la flore doivent être réduits. L’application cible vise des zones géographiques inférieures à 1km2 dans lesquelles les transmissions de flux vidéo et de mesures, prélevés par des capteurs immergés, doivent être réalisées sans-fil sur des distances supérieures à 10m avec un débit minimum de 80kbps pour des puissances d’émission d’une dizaine de Watts. Une étude comparative des méthodes de communication acoustiques, optiques et électromagnétiques en eau de mer est présentée. Cette analyse est introduite en définissant un ensemble de critères de performances destinés à évaluer et sélectionner la technique la mieux adaptée aux besoins applicatifs. Les méthodes électromagnétiques, dont les coûts de déploiements et l’impact environnemental sont minimaux, présentent toutefois des limitations de portée pour le débit de données souhaité. La suite de cette thèse présente les travaux de recherche qui ont été menés pour lever ces verrous technologiques. Un premier modèle simplifié de propagation des champs électromagnétiques en milieu subaquatique a été développé pour différencier les modes de propagation favorisant les pertes par conduction de celles engendrées par les propriétés diélectriques de l’eau de mer. Des prototypes d’antennes ont été développés pour tenter d’exciter le milieu en favorisant l’un ou l’autre mode. Finalement, l’étude détaillée d’un modèle de couplage magnéto-inductif a permis de réaliser et d’évaluer les performances d’une telle liaison en utilisant des techniques originales d’élargissement de bande passante qui ont été implémentées avec succès dans un prototype de MODEM sous-marin<br>Monitoring the underwater environment requires the deployment of dedicated sensors and infrastructure whose cost and impact on flora and fauna must be reduced. The target application aims geographic areas of less than 1km2 in which transmissions of video streams and measurements, taken by submerged sensors, must be carried out wirelessly over distances greater than 10m with a minimum bit rate of 80kbps for powers of emission around a dozen of Watts. A comparative study of acoustic, optical and electromagnetic communication methods in seawater is presented. This analysis is introduced by defining a set of performance criteria intended to assess and select the technique best suited to application needs. The electromagnetic methods, whose deployment costs and environmental impact are minimal, however presents limitations of ranges for the desired data rate. The remainder of this thesis presents the research work that has been carried out to remove these technological obstacles. A first simplified model of propagation of electromagnetic fields in an underwater environment has been developed to differentiate the propagation modes favouring conduction losses from those caused by the dielectric properties of sea water. Prototype antennas have been developed to try to excite the medium by favouring one or the other mode. Finally, the detailed study of a magneto-inductive coupling model made it possible to carry out and evaluate the performance of such a link using original bandwidth widening techniques which were implemented successfully in an underwater MODEM prototype
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Bizagwira, Honoré. "Réseaux de capteurs sans fil étendu robuste exploitant des liens atypiques." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22770/document.
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Ce mémoire de thèse se place dans le contexte des applications de surveillance de l’environnement nécessitant des mesures régulières de caractéristiques biologiques ou géo-physiques. Il s’agit par exemple de mesurer la propagation de polluants dans les cours d’eau, de surveiller le développement de bactérie dans des eaux de baignade. Les réseaux de capteurs sans fils (RCsF) apparaissent comme des solutions économiques et fiables pour permettre l’automatisation de la collecte de telles données. Le bon fonctionnement de ces réseaux dépend de la qualité des transmissions radio, ce qui est particulièrement vrai dans des milieux où les conditions sont peu favorables à la propagation des ondes radio et où les liens peuvent donc se révéler intermittents. L’objectif de ce travail est de proposer une solution protocolaire efficace dans de telles conditions, dans le cas particulier d’un réseau de capteur déployé à la surface de l’eau. Le mémoire débute par la description d’une méthodologie, des mécanismes et d’une plate-forme destinée à explorer la qualité d’un lien radio situé à la surface de l’eau. Nous présentons différentes mesures qui ont été effectuées. Les solutions protocolaires que nous proposons prennent en compte le caractère évolutif de la topologie due à l’instabilité des liens radio afin d’améliorer l’efficacité de la collecte et de réduire la consommation énergétique des noeuds. Notre approche est basée sur la reconstruction périodique de la topologie, la communication entre les noeuds par rendez-vous définis par des fenêtres de transmissions, l’utilisation du multi-canal pour drainer les données et l’adaptation de la taille des fenêtres de transmission en fonction du trafic local. L’ensemble de ces propositions est validé par prototypage et par simulation sur NS-3. Les résultats montrent que notre solution est capable de collecter les données dans une topologie dynamique tout en réduisant à la fois le délai de collecte et la consommation énergétique<br>This thesis takes place in the context of environmental monitoring applications requiring regular measurements of biological or geophysical characteristics. These applications include for instance the measuring of the spread of pollutants in rivers, monitoring of the development of bacteria in bathing waters, etc. Wireless Sensor Networks (WSNs) provide cost-effective and reliable solutions to allow the automation of such data gathering. The good functioning of these networks depends on the quality of the radio transmissions, which is particularly true in environments where the conditions are not suitable for the propagation of radio waves and where the links may therefore be intermittent. The objective of this work is to propose an effective protocol solution under such conditions, in the particular case of a sensor network deployed on the water surface. The thesis begins with a description of the methodology, mechanisms and a platform for exploring the quality of a radio link displayed at the water surface. We present different measures that have been carried out. The protocol solutions we propose take into account the evolutionary nature of the topology due to the instability of the radio links in order to improve the efficiency of the data gathering and to reduce the energy consumption of the nodes. Our approach is based on the periodic reconstruction of the topology, the communication between nodes by appointments defined by transmission windows, the use of the multi-channel to drain the data and the adaptation of the transmission window size as a function of local traffic. All these propositions are validated by prototyping and simulation using NS-3. The results show that our solution is capable of collecting data in a dynamic topology while reducing both gathering time and energy consumption
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Aby, Affoua Thérèse. "Réseaux de capteurs sans fil étendus dédiés aux collectes de données environnementales." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22671/document.
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Les réseaux de capteurs sans fil sont utilisés dans de nombreuses applications de surveillance de l’environnement (par exemple, pour surveiller les volcans ou pour détecter les incendies de forêts). Dans de telles applications, les nœuds capteurs disposent d’une quantité limitée d’énergie, mais doivent fonctionner pendant des années sans avoir leurs batteries changées. La principale méthode utilisée pour permettre aux nœuds d’économiser leur énergie est de séquencer les périodes d’activité et d’inactivité. Cependant, la conception de protocoles MAC et de routage pour les applications avec des taux d’activité faibles est un défi. Dans cette thèse nous proposons des protocoles MAC avec de très faibles taux d’activité (moins de 1% d’activité) et des protocoles de routages adaptés pour des réseaux de capteurs sans fil dédiés aux applications de surveillance environnementale. Nos protocoles sont analysés et comparés aux protocoles existants par simulation et par expérimentation sur des nœuds TelosB. Malgré un taux d’activité très faible pour tous les nœuds, nos protocoles sont capables d’obtenir de bonnes performances, contrairement aux autres protocoles de la littérature, qui ne sont pas adaptés à opérer avec de faibles taux d’activité<br>Wireless sensor networks are used in many environmental monitoring applications (e.g., to monitor forest fires or volcanoes). In such applications, sensor nodes have a limited quantity of energy, but must operate for years without having their batteries changed. The main mechanism used to allow nodes to save energy is to sequence periods of activity and inactivity. However, the design of MAC and routing protocols for applications with low duty-cycle is still a challenge. In this thesis, we proposed unsynchronized MAC and routing protocols for wireless sensor networks devoted to environmental monitoring applications. The main specificity of our protocols is that they are adapted to very low duty-cycle (less than 1 % for all nodes). Our protocols are analyzed and compared to existing protocols by simulation and experimentation on TelosB nodes. Despite this low duty-cycle for all nodes, our protocols are able to achieve good performance, unlike other protocols in the literature, which are not adapted to these extreme conditions
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Chaves, Luiz Carlos Guerreiro. "Salinidade e impacto da irrigaÃÃo no Distrito de IrrigaÃÃo do PerÃmetro Araras Norte,Dipan, CearÃ." Universidade Federal do CearÃ, 2006. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=2205.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico<br>O presente trabalho foi desenvolvido com o propÃsito de avaliar a adiÃÃo de sais ao solo pela irrigaÃÃo ao longo do tempo, em Ãrea cultivada com parreira, bem como o efeito das chuvas na lixiviaÃÃo dos sais, tomando-se como referencial o status salino do solo da mata nativa. Foram avaliadas tambÃm a influÃncia dos Ãons na condutividade elÃtrica do extrato de saturaÃÃo do solo. O trabalho foi realizado em Ãrea localizada no Distrito de IrrigaÃÃo do PerÃmetro Araras Norte (DIPAN), CearÃ. A Ãrea vem sendo irrigada desde 2001 com Ãgua classificada como C1S2 e o sistema de irrigaÃÃo empregado à a microaspersÃo. Para se monitor o movimento dos sais no perfil do solo foram coletadas amostras na Ãrea irrigada e na mata nativa para as camadas de 0 a 0,30 m; 0,30 a 0,60 m; 0,60 a 0,90 m e 0,90 a 1,20 m, no perÃodo de maio de 2003 a setembro de 2005, perfazendo um total de 120 amostras. Os atributos considerados neste estudo foram a Condutividade ElÃtrica (CE) e os Ãons Ca2+, Mg2+, Na+, K+ e Cl-. Para se qualificar o impacto da irrigaÃÃo e o efeito das chuvas na lixiviaÃÃo dos sais aplicou-se o teste t de Student ao nÃvel de 1% para a comparaÃÃo de mÃdias de amostras independentes da CE, utilizando o pacote estatÃstico SPSS v.10,0. Efetuou-se a identificaÃÃo dos Ãons para os quais a CE apresentou maior sensibilidade Ãs profundidades de 0 a 0,30 m; 0,30 a 0,60 m; 0,60 a 0,90 m e 0,90 a 1,20 m. Os resultados mostraram concentraÃÃes de sais maiores na Ãrea irrigada do que na mata nativa para todas as camadas estudadas, sendo que as maiores diferenÃas foram registradas para a camada de 0 a 0,30 m. O magnÃsio foi o Ãon que apresentou maior influÃncia nos valores de condutividade elÃtrica, enquanto o cloreto apresentou baixa concentraÃÃo nas camadas inferiores. O maior incremento de Ãons na Ãrea irrigada em relaÃÃo à mata nativa ocorreu com o cÃlcio. Os sais totais retidos no solo da Ãrea irrigada apresentaram diferenÃa significativa ao nÃvel de 1% quando comparados com os da mata nativa. A pluviometria total anual nÃo foi suficiente para promover uma lixiviaÃÃo significativa dos sais adicionados ao solo pela irrigaÃÃo. O impacto da irrigaÃÃo mostrou-se altamente significativo expressando risco de salinizaÃÃo da Ãrea irrigada.
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Silva, Rodrigo. "ITS-based decision making mechanism for opportunistic networking in heterogeneous network environment." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2020. http://www.theses.fr/2020IMTA0174.
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Le nombre de véhicules connectés augmentent et pour une utilisation plus intelligente des systèmes de transport, les véhicules ont besoin d’accroître leur connaissance de l’environnement. Cela peut être atteint en permettant aux véhicules de communiquer avec leur environnement. Pour une connectivité omniprésente, il sera nécessaire d’utiliser diverses technologies sans fil, existantes. Dans un tel environnement de réseau d’accès hétérogène, il est nécessaire de fournir aux applications des mécanismes décisionnels transparents pour gérer l’affectation des flux de données sur les réseaux disponibles. Dans cette thèse, nous proposons le Ant-based Decision Maker for Opportunistic Networking (AD4ON), un Decision Maker (DM) mécanisme modulaire capable de choisir le meilleur profil de communication disponible pour chaque fluxde données dans un environnement de réseau hétérogène et dynamique. Le mécanisme proposé gère les exigences et préférences de différents acteurs (applications, utilisateurs,etc.), ainsi que les information réseaux dans un futur proche, afin de prendre des décisions plus intelligentes. C’est-à-dire, afin d’augmenter la satisfaction de chaque acteur impliqué dans le processus de communication, ainsi que d’augmenter la stabilité de la décision (par exemple, en réduisant l’effet “ping-pong“)<br>Demand from different actors for extended connectivity where vehicles can exchange data with other devices have pushed vehicle manufacturers to invest in embedded solutions, which paves the way towards Cooperative Intelligent Transportation Systems (C-ITS). Cooperative vehicles enable the development of an ecosystem of services around them. Due to the heterogeneousness of such services and their specific requirements, for ubiquitous connectivity it is necessary to combine existing wireless technologies, providing applications with a communication architecture that hides such underlying access technologies specificities. Moreover, due to vehicles’ high velocity it is needed a Decision Maker (DM) mechanism capable to take into account the short-term prevision about network environment in order to better manage all flow communications. Based on the Intelligent Transportation Systems (ITS) architecture proposed by International Organization for Standardization (ISO), we proposed the Ant-based Decision Maker for Opportunistic Networking (AD4ON), a modular decision maker mechanism capable to choose the best available access network for each data flow in an heterogeneous and dynamic network environment. The proposed mechanism manages requirements and preferences from different actors, taking into account the short-term prevision about the network environment. Simulations have demonstrated that the AD4ON outperforms current benchmark algorithms, by increasing decision’s stability, reducing the “ping-pong” effect and maximizing flow’s satisfaction. Moreover, we demonstrate that taking into account the short-term prevision, the AD4ON can optimize the algorithm reaction time
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Berglund, Ove. "Implementation of Lead-Free Soldering in Highly Reliable Applications." Thesis, Linköping University, Department of Science and Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8779.
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<p>The directive of the European parliament and of the council on the Restriction of the use of certain Hazardous Substances (RoHS) in Electrical and Electronic Equipment (EEE) took effect in the European Union on July 1, 2006. Japan, California, China and Korea are all closed markets for exporters of components containing lead from July 1, 2007. Taiwan and Australia are working with similar directives. The RoHS directive is the reason why this thesis about the implementation of lead-free soldering in highly reliable applications is necessary.</p><p>The European Lead Free soldering NETwork (ELFNET) status survey from 2005 shows that the majority of the companies are well informed, but 20% are still not active in lead-free soldering. The Swedish industry is for the most part prepared and 95% of the components are lead-free. The transition to lead-free soldering will have a major affect on logistics and administration, because the RoHS directive is 90% about administration and logistics problems. Only 10% is technical problems.</p><p>The higher melting point in lead-free soldering affects every stage of the lead-free manufacturing, from assembly to testing and repair.</p><p>The major concern for highly reliable applications are that there are not enough data to understand to what grade lead-free solders will perform differently from lead based solders. Five different types of reliability testing were studied in this thesis; vibration, mechanical shock, thermal shock, thermal cycling and combined environments. Whiskers, voids, brittle fractures and mixed assembly problems were also studied. Individual tests alone should not be used to make definite decisions on lead-free soldering reliability. The lower reliability for lead-free solders in some tests does not necessarily mean that lead-free solders not can be used in highly reliable applications like defence electronics.</p><p>The most important conclusions from this thesis are:</p><p>• Update or change the logistic system and mark/label according to available standards.</p><p>• Secure a good board layout.</p><p>• Secure a good process control.</p><p>• Alternative surface board should be used. Tin-silver-copper (SAC) is the most reliable solder and Electroless Nickel/Immersion Gold (ENIG) is the most reliable surface finish.</p><p>• Remember that the higher temperature affects every stage of the manufacturing.</p><p>• No increased problems with whiskers or risk of high voiding levels.</p><p>• Mixed assembly is a risk. Compatibility and contamination risks must be taken seriously.</p><p>• Which environment will the applications be in? If it is not a highly vibrating and thermal cycling environment, lead-free soldering should be safe to use.</p><br><p>Europaparlamentets och rådets direktiv om begränsning av användningen av vissa farliga ämnen i elektriska och elektroniska produkter började gälla i Europeiska unionen 1 juli, 2006. Japan, Kalifornien, Kina och Korea är alla stängda marknader för exportörer av komponenter som innehåller bly från och med 1 juli, 2007. Taiwan och Australien arbetar med liknande direktiv. RoHS-direktivet är anledningen till varför detta examensarbete om implementeringen av blyfri lödning i högtillförlitliga applikationer är nödvändigt.</p><p>En undersökning från 2005 av ELFNET visar att majoriteten av företagen är väl informerade, men 20% är fortfarande i aktiva med blyfri lödning. Den svenska industrin är till största delen väl förberedd och 95% av komponenterna är blyfria. Övergången till blyfri lödning kommer att ha stor effekt på logistik och administration, därför att 90% är administrations- och logistikproblem i RoHS-direktivet. Bara 10% är tekniska problem.</p><p>Den högre smälttemperaturen i blyfri lödning påverkar varje steg av den blyfria tillverkningen, från montering till testning och reparation.</p><p>Den stora oron för högtillförlitliga applikationer är att det inte finns tillräckligt med data för att förstå i vilken grad som blyfria lod kommer att bete sig annorlunda jämfört med blybaserade lod. Fem olika typer av tillförlitlighetstester har undersökts i detta examensarbete; vibration, mekanisk chock, termisk chock, termisk cykling och kombinerade tester. Whiskers, voids, sprödbrott och blandad montering studerades också. Individuella tester ska inte användas för att ta några definitiva beslut om blyfri lödnings tillförlitlighet. Den lägre tillförlitligheten för blyfria lod i en del tester behöver nödvändigtvis inte betyda att blyfria lod inte kan användas i högtillförlitliga applikationer som försvarselektronik.</p><p>De viktigaste slutsatserna från detta examensarbete är:</p><p>• Uppdatera eller byt logistiskt system och märk enligt tillgängliga standarder.</p><p>• Säkerställ en bra kretskortsdesign.</p><p>• Säkerställ en bra processkontroll.</p><p>• Alternativa mönsterkort bör användas. SAC är det tillförlitligaste lodet och ENIG är den tillförlitligaste ytbehandlingen.</p><p>• Kom ihåg att den ökade temperaturen påverkar varje steg i tillverkningen.</p><p>• Inga ökade problem med whiskers eller stort antal voids.</p><p>• Blandmontage är riskfyllt. Kompatibilitet och risker med kontaminering måste tas på allvar.</p><p>• Vilken miljö kommer applikationen att befinna sig i? Är det inte en starkt vibrerande eller temperaturcyklisk miljö bör blyfri lödning vara säkert att använda.</p>
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Arfaoui, Ghada. "Conception de protocoles cryptographiques préservant la vie privée pour les services mobiles sans contact." Thesis, Orléans, 2015. http://www.theses.fr/2015ORLE2013/document.
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Avec l'émergence de nouvelles technologies telles que le NFC (Communication à champ proche) et l'accroissement du nombre de plates-formes mobiles, les téléphones mobiles vont devenir de plus en plus indispensables dans notre vie quotidienne. Ce contexte introduit de nouveaux défis en termes de sécurité et de respect de la vie privée. Dans cette thèse, nous nous focalisons sur les problématiques liées au respect de la vie privée dans les services NFC ainsi qu’à la protection des données privées et secrets des applications mobiles dans les environnements d'exécution de confiance (TEE). Nous fournissons deux solutions pour le transport public: une solution utilisant des cartes d'abonnement (m-pass) et une autre à base de tickets électroniques (m-ticketing). Nos solutions préservent la vie privée des utilisateurs tout en respectant les exigences fonctionnelles établies par les opérateurs de transport. À cette fin, nous proposons de nouvelles variantes de signatures de groupe ainsi que la première preuve pratique d’appartenance à un ensemble, à apport nul de connaissance, et qui ne nécessite pas de calculs de couplages du côté du prouveur. Ces améliorations permettent de réduire considérablement le temps d'exécution de ces schémas lorsqu’ils sont implémentés dans des environnements contraints par exemple sur carte à puce. Nous avons développé les protocoles de m-passe et de m-ticketing dans une carte SIM standard : la validation d'un ticket ou d'un m-pass s'effectue en moins de 300ms et ce tout en utilisant des tailles de clés adéquates. Nos solutions fonctionnent également lorsque le mobile est éteint ou lorsque sa batterie est déchargée. Si les applications s'exécutent dans un TEE, nous introduisons un nouveau protocole de migration de données privées, d'un TEE à un autre, qui assure la confidentialité et l'intégrité de ces données. Notre protocole est fondé sur l’utilisation d’un schéma de proxy de rechiffrement ainsi que sur un nouveau modèle d’architecture du TEE. Enfin, nous prouvons formellement la sécurité de nos protocoles soit dans le modèle calculatoire pour les protocoles de m-pass et de ticketing soit dans le modèle symbolique pour le protocole de migration de données entre TEE<br>The increasing number of worldwide mobile platforms and the emergence of new technologies such as the NFC (Near Field Communication) lead to a growing tendency to build a user's life depending on mobile phones. This context brings also new security and privacy challenges. In this thesis, we pay further attention to privacy issues in NFC services as well as the security of the mobile applications private data and credentials namely in Trusted Execution Environments (TEE). We first provide two solutions for public transport use case: an m-pass (transport subscription card) and a m-ticketing validation protocols. Our solutions ensure users' privacy while respecting functional requirements of transport operators. To this end, we propose new variants of group signatures and the first practical set-membership proof that do not require pairing computations at the prover's side. These novelties significantly reduce the execution time of such schemes when implemented in resource constrained environments. We implemented the m-pass and m-ticketing protocols in a standard SIM card: the validation phase occurs in less than 300ms whilst using strong security parameters. Our solutions also work even when the mobile is switched off or the battery is flat. When these applications are implemented in TEE, we introduce a new TEE migration protocol that ensures the privacy and integrity of the TEE credentials and user's private data. We construct our protocol based on a proxy re-encryption scheme and a new TEE model. Finally, we formally prove the security of our protocols using either game-based experiments in the random oracle model or automated model checker of security protocols
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Fancello, Laura. "A viral metagenomic approach to study taxonomic and functional diversity of viral communities from the environment to humans." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM5046/document.
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Les virus sont les entités biologiques les plus abondantes et diversifiées sur Terre et leur diversité est encore très peu connue. Récemment, la métagénomique virale a facilité l'exploration de cette diversité. Néanmoins, la plupart des viromes environnementaux générés à ce jour proviennent de régions tempérées et la plupart des viromes humains proviennent d’échantillons de selles, sang ou de prélèvements oro-naso-pharyngés. L'objectif de mon travail de thèse était d’apporter de nouvelles connaissances sur les communautés virales d’environnements et d’échantillons humains les moins étudiés en utilisant une approche de métagénomique virale.La première partie de cette thèse est une revue des principaux outils d'analyse des métagénomes viraux. La deuxième partie présente la première étude de métagénomique virale dans le désert du Sahara. Dans la troisième partie de ma thèse, je présente de viromes associés a l'Homme: i) le premier métagénome viral issu d'un coprolithe humain du Moyen Âge; ii) la première étude de métagénomique virale sur de liquides péricardiques provenant de patients atteints d’une péricardite infectieuse d'origine inconnue; iii) une analyse fonctionnelle de métagénomes viraux précédemment publiés associés aux expectorations de patients atteints de mucoviscidose qui décrit les gènes de résistance aux antibiotiques portés par les bactériophages dans ces patients.Ce travail présente ainsi des données inédites sur certaines communautés virales peu étudiées et confirme le potentiel de la métagénomique virale pour étudier la diversité virale, révéler la présence de virus inattendus ou inconnus et comprendre leur rôle dans leur écosystème d’origine<br>Viruses are the most abundant and diverse organisms but little is known about their diversity. Recently, viral metagenomics has allowed performing broad unselective exploration of uncultivated viral communities, bypassing the limits of classical viral detection tools. However, most viral metagenomes are generated from temperate regions (for environmental studies) or from modern stool samples, sera/blood and naso-/oro- pharyngeal samples (for human-associated studies). Therefore, the purpose of my thesis is to study viral communities in the least investigated environments or human samples, using viral metagenomics.The first part of my thesis is a review of the main computational tools for the analysis of viral metagenomes. The second part of my thesis presents the first viromes generated from the Sahara desert. In the third part, I investigate human-associated viral communities: i) the first virome from a human coprolite; ii) the first viromes generated from human pericardial fluids, in idiopathic pericarditis cases; ii) a functional-level investigation of previously described viral metagenomes from cystic fibrosis patient sputa that focuses on antimicrobial resistance genes carried by bacteriophages to better understand the emergence of multidrug-resistance bacteria in the airways of cystic fibrosis patients.This thesis work provides original data on unexplored viral communities and shows the potential of viral metagenomics to give insights on viral diversity, reveal the presence of expected and unexpected viruses and decipher their role in the ecosystem
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Sauvage, Chloé. "Impact de l'environnement atmosphérique sur les liaisons optiques sans fil pour la ville du futur." Electronic Thesis or Diss., Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAT027.
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Les liens de télécommunications optiques en espace libre sont amenés à se répandre. En particulier car leur déploiement est simple, rapide et économique au contraire des réseaux fibrés. Néanmoins leur fragilité face aux faibles visibilités et au-delà de quelques kilomètres de portée freine leur utilisation. Connaître plus finement le canal atmosphérique urbain sous toutes conditions météorologiques est donc nécessaire afin d’apporter les solutions pour fiabiliser ce type de liaison, notamment avec le choix d’une longueur d’onde adaptée. La première partie de cette thèse introduit le fonctionnement des liens de télécommunications optiques expérimentaux et décrit les différents phénomènes atmosphériques, tel que l’atténuation et la turbulence, auxquels sont soumis les faisceaux laser se propageant sur plusieurs kilomètres en espace libre. La seconde partie présente deux études, pour la première j’ai modélisé un lien optique afin de déterminer sa disponibilité en fonction de différentes longueurs d’onde et conditions atmosphériques. Dans la seconde étude j’ai déterminé, à l’aide de mesures réelles, l’évolution temporelle du canal atmosphérique en présence de turbulence. La troisième partie valide la méthode de reconstruction du Cn², distribué le long du canal turbulent. La dernière partie de cette thèse porte sur le travail préparatoire d’un lien expérimental à λ = 4 µm qui permettra de relier la performance télécom et l’état du canal, en terme de turbulence, caractérisée par de la constante de l’indice de réfraction, Cn². L’ensemble de ces travaux constitue une première étape dans la mise en œuvre de liens de télécommunications optiques en espace libre fonctionnant sous toutes conditions météorologiques<br>The free space optical (FSO) communication will be set to expand. Especially because they have easier, faster and cheaper deployment than optical fiber network. However, they present weakness in front of low visibility and beyond a range of few kilometers, thus slow down their use.The refined knowledge of the urban atmospheric channel is required in order to bring reliability solution to this technology, in particular with the choice of an appropriate wavelength.The first part of this thesis introduces the experimental FSO operation and describes the different atmospheric phenomena, such as attenuation and turbulence, which affect the laser beam propagation on few kilometers in free space.The second part presents two studies, for the first, I modeled FSO links in order to determine its availability as a function of different wavelength and atmospheric conditions. In the second study, I determined, with real measurements, the temporal evolution of an atmospheric turbulent channel. The third part validates the method Cn² reconstruction, distributed along the turbulent channel. The last part concerns the preparatory study of an experimental FSO link at λ = 4 µm which will relate the telecom performance and the channel state, in term of turbulence, characterized by the refractive index structure constant Cn². All this work constitutes a first step in the FSO links implementation under all weather conditions
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OCHOA, Juliana Herlemann. "Análise do conforto ambiental em salas de aula da Universidade Federal de Goiás." Universidade Federal de Goiás, 2010. http://repositorio.bc.ufg.br/tede/handle/tde/1329.
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Previous issue date: 2010-09-24<br>Provide users good physical conditions in educational institutions is essential for the proper
development of teaching and learning. This work deals with the verification in-loco of the
environmental comfort of classrooms in two buildings with different architectural and
construction techniques, that are part of the structure of the Federal University of Goiás. So
the research aimed at exploring these buildings in order to identify the peculiarities of its
thermal, acoustic and light performance which are being influenced by the technologies
adopted and the physical conformation of the same. The technical data collected were
analyzed by type of comfort. In lighting comfort, measurements were carried out near the
solstices and equinoxes and the data collected were analyzed by means of ambient
illuminance, uniformity coefficient and contribution of artificial light. The thermal comfort data
collected were temperature and relative humidity for a period of approximately 11 months,
which were assessed using the concept of comfort zone, degree-hours analysis and absolute
maximum and minimum values. The acoustic measurements collected the sound pressure
levels and occurred over a day of daily activities in both buildings. It was noted that there is
an influence of the architectural elements of environmental comfort in buildings. Among other
factors, one that can be highlighted is that despite having similar solar orientation, which is a
comfort condition, the results of the environmental performance of each of the buildings were
quite different. Parallel to these technical assessments were also done a periodic application
of questionnaires to the users of the classroom, one per season, which sought to
characterize the perception of these in relation to each of the types of comfort. Finally, a
correlation was established between the technical data collected and perceptive. In most of
cases, the opinions expressed by users were not consistent with the results evaluated by
measurement techniques, thus demonstrating a difference between the comfort zone
adopted and the actual user satisfaction of the buildings.<br>Proporcionar aos usuários boas condições físicas nas instituições educacionais é
determinante para o adequado desenvolvimento das atividades de ensino e aprendizado.
Este trabalho trata da avaliação in loco do conforto ambiental de salas de aula de duas
edificações com arquitetura e técnicas construtivas diferentes, que compõe a estrutura da
Universidade Federal de Goiás. Desta maneira, a pesquisa objetiva explorar estas
edificações buscando identificar, em cada uma delas, peculiaridades de seu desempenho
térmico, acústico e lumínico, que estejam sendo influenciadas pelas tecnologias adotadas e
pela conformação física das mesmas. Os dados técnicos levantados foram avaliados por
tipologia de conforto. No conforto lumínico, realizaram-se medições próximas aos solstícios
e equinócios e os dados coletados foram analisados pelas iluminâncias médias dos
ambientes, coeficiente de uniformidade e contribuição da luz artificial. Os dados de conforto
térmico coletados foram: temperatura e umidade relativa, por um período de
aproximadamente 11 meses, os quais foram avaliados por meio do conceito de zona de
conforto, análise graus-hora e valores máximos e mínimos absolutos. As medições
acústicas coletaram os níveis de pressão sonora e ocorreram ao longo de um dia de
atividades cotidianas, em ambas as edificações. Notou-se, que há uma influência dos
elementos arquitetônicos no conforto ambiental das edificações. Entre outros fatores, um
que pode ser destacado é que, apesar de possuírem orientação solar similar, que é um
aspecto condicionante de conforto, os resultados do desempenho ambiental, de cada um
dos edifícios, foram bastante diferenciados. Paralela a estas avaliações técnicas, foi também
realizada uma aplicação periódica de questionários aos usuários das salas estudadas,
sendo uma por estação do ano, que buscou caracterizar a percepção destes, em relação a
cada uma das tipologias de conforto. Finalmente, foi estabelecida uma correlação entre os
dados técnicos levantados e os perceptivos. Em parte dos casos, as opiniões expressadas
pelos usuários não foram condizentes com os resultados avaliados por meio das medições
técnicas, demonstrando assim uma divergência entre a zona de conforto adotada e a real
satisfação dos usuários das edificações.
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Kalaagi, Mohammed. "Métasurfaces pour la récupération d'énergie électromagnétique et le transfert d'énergie sans fil dans l'environnement ferroviaire." Electronic Thesis or Diss., Université de Lille (2018-2021), 2021. http://www.theses.fr/2021LILUI049.
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L'intérêt pour l'alimentation en énergie électrique des différents composants de l'infrastructure ferroviaire est devenu un sujet de recherche intéressant avec le gain de popularité des systèmes ferroviaires. Pour développer un système ferroviaire intelligent, fiable, et autonome, notamment avec l'essor de différentes technologies telles que les dispositifs de l'Internet des objets et les nœuds de capteurs sans fil , l'alimentation électrique est nécessaire pour que les dispositifs soient mis en œuvre de manière fiable et autonome. Les technologies de collecte d'énergie et de transfert d'énergie sans fil peuvent être un élément clé pour l'alimentation de ces dispositifs, afin de construire un système suffisant et pratique. Il a été démontré qu'un niveau élevé d'énergie électromagnétique existe jusqu'à la région des micro-ondes à fort potentielL'objectif de ce travail est de développer de nouveaux concepts basés sur les métasurfaces, afin d'améliorer le potentiel et la performance de la récolte d'énergie EM et des technologies WPT qui peuvent être compatibles avec l'application dans l'environnement ferroviaire. Le principal défi consiste à concevoir un dispositif efficace et compact, en particulier pour les basses fréquences MHz, où les systèmes rectenna être insuffisants.Nous proposons tout d'abord un nouveau concept pour améliorer l'efficacité des systèmes conventionnels EM ou des systèmes de rectenna commercialisés sur étagère. Ce concept est basé sur la focalisation des ondes EM ambiantes dans une zone où elles peuvent être captées par un système de rectenna. La conception d'une métasurface de focalisation basée sur le profil hyperboloïde de la loi de phase généralisée est proposée : l'énergie électromagnétique ambiante incidente dans le champ lointain est concentrée en un point appelé point focal à une distance donnée de la conception de la métasurface. La métasurface est simulée et des validations expérimentales en champ proche et en champ lointain sont proposées. Des mesures ont été effectuées dans la chambre anéchoïque pour valider le concept en utilisant un système de rectenna commercialisé et la conception de la métasurface de focalisation à 900 MHz. Les résultats ont montré que, lors de la mise en œuvre du système rectenna à côté de la métasurface de focalisation, la puissance reçue est améliorée d'un facteur 5. Des essais sur le terrain ont ensuite été réalisés : le système a été mis en œuvre dans l'environnement ferroviaire en présence d'une station de base GSM-R. Les résultats ont montré que, lorsque la métasurface est mise en œuvre à côté du dispositif à antenne rectangulaire, une puissance reçue de -20 dBm est obtenue, ce qui peut être suffisant pour réveiller des dispositifs à faible puissance d'entrée tels que des capteurs sans fil, que le dispositif à antenne rectangulaire seul a donné de mauvais résultats avec une puissance reçue d'environ -40 dBm.Une solution alternative pour l'alimentation électrique sans fil dans le système ferroviaire est le WPT. l'un des principaux défis pour ces technologies dans ce cas peut être la ligne de vue avec des problèmes de mobilité : un meilleur suivi et un angle de détection plus large du dispositif alimenté sont nécessaires. Dans ce cas, la conception de métasurfaces rétrodirectives multi-angles basée sur différents concepts tels que la mise en cascade de diverses conceptions de super-cellules métamatérielles et la modulation d'impédance de surface est proposée. Ces conceptions peuvent être mises en œuvre à côté du dispositif alimenté , afin d'améliorer la localisation et le suivi du dispositif alimenté au-delà des limites communes de la ligne de signal atteignant des angles d'incidence obliques extrêmes. D'autres solutions pour l'amélioration de l'efficacité et la miniaturisation des systèmes de récolte d'énergie EM basés sur des métasurfaces absorbantes sont proposées aux basses fréquences micro-ondes<br>The interest for electric energy power supply to different components in the railway infrastructure, has become an interesting research topic with the gain of popularity for railway systems. To develop a smart, reliable, safe and autonomous railway system, specially with the rise of different technologies such as Internet of things (IoT) devices and wireless sensor nodes (WSN), electric power supply is needed for such that devices are implemented in a reliable and autonomous manner. Energy harvesting and wireless power transfer (WPT) technologies can be a key element for power supply to such devices, to build a sufficient and convenient system. A high level of EM energy has been shown to exist up to the microwave region and which can have a high potential for EM energy harvesting.The aim of this work is to develop novel concepts based on metasurfaces, to enhance the potential and performance of EM energy harvesting and WPT technologies which can be compatible for the application in the railway environment. The main challenge is to design an efficient and compact device specially at low MHz frequencies where conventional rectenna systems can be insufficient.We first propose a novel concept to enhance the efficiency of EM conventional or off-the-shelf commercialized rectenna systems. It is based on the focusing of the ambient EM waves in an area where it can be harvested by a rectenna system. The design of focusing metasurface based on the hyperboloidal profile of the generalized phase law is proposed: the incident ambient EM energy in the far-field, is concentrated at a point known as the focal point at a given distance from the metasurface design. The metasurface designed is simulated and experimental validations in both near field and far field are proposed. Measurements have been carried in the anechoic chamber to validate the concept using a commercialized rectenna system and the focusing metasurface design at 900 MHz. The results have shown that, when implementing the rectenna system along side the focusing metasurface, the received power is enhanced by a factor of 5. Field tests were then conducted: the system was then implemented in the railway environment in the presence of a GSM-R base station, where the results have shown that, when implementing the metasurface along side the rectenna device, -20 dBm of received power was achieved which can be sufficent to wake up low-input-power devices such as wireless sensors, whereas the rectenna device (commercial energy harvester) alone showed poor results of received power around -40 dBm.An alternative solution for wireless electric power supply in the railway system is WPT. However, one of the main challenges for such technologies in this case can be line of sight with mobilty issues: better tracking and wider detection angle of the fed device is required. In this case, the design of multi-angle retrodirective metasurfaces based on different concepts such as cascading of various metamaterial super-cell designs, and surface impedance modulation are proposed. These designs can be implemented along side the fed device (IoT or WSN), in order to enhance the localization and tracking of the fed device beyond the common line-of-signt limitations reaching extreme oblique incident angles. Other solutions for efficiency enhancement and miniaturization for EM energy harvesting systems based on absorbing metasurfaces are proposed at low microwave frequencies
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Holland, Kerry Lenore. "Implementation of a virtual haptic back." Ohio : Ohio University, 2001. http://www.ohiolink.edu/etd/view.cgi?ohiou1173898052.
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Reis, Ana Flávia dos. "New Baseband Architectures Using Machine Learning and Deep Learning in the Presence of Nonlinearities and Dynamic Environment." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS023.
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La futur sixième génération (6G) de systèmes de communication sans fil devrait permettre un large éventail de nouvelles applications dans le domaine de la communication véhiculaire, ce qui s'accompagne d'un ensemble varié de défis et d'opportunités résultant des exigences de cette technologie de pointe. En particulier, ces défis découlent des conditions dynamiques des canaux, y compris les canaux variables dans le temps et les non-linéarités induites par les amplificateurs de puissance. Dans ce contexte complexe, l'estimation des canaux sans fil apparaît comme un élément essentiel pour établir une communication fiable. En outre, le potentiel de l'apprentissage automatique et de l'apprentissage profond dans la conception d'architectures de récepteurs adaptées aux réseaux de communication véhiculaires est évident, étant donné leurs capacités à exploiter de vastes ensembles de données, à modéliser des conditions de canal complexes et à optimiser la performance des récepteurs. Au long de cette recherche, nous avons tiré parti de ces outils potentiels pour faire progresser l'état de l'art en matière de conception de récepteurs pour les réseaux de communication véhiculaires. Ainsi, nous avons exploré les caractéristiques de l'estimation des canaux sans fil et de l'atténuation des distorsions non linéaires, en reconnaissant qu'il s'agit de facteurs importants pour la performance des systèmes de communication. À cette fin, nous proposons de nouvelles méthodes et des récepteurs flexibles, basés sur des approches hybrides qui combinent des modèles mathématiques et des techniques de l'apprentissage automatique, en tirant parti des caractéristiques uniques du canal véhiculaire pour promouvoir une estimation précise. Notre analyse couvre à la fois la forme d'onde des communications sans fil conventionnelles et une forme d'onde prometteuse de la 6G, ce qui démontre la complétude de notre approche. Les résultats des approches proposées sont prometteurs, caractérisés par des améliorations substantielles de la performance et des réductions notables de la complexité du système. Ces résultats offrent un potentiel pour des applications dans le monde réel, marquant un pas vers l'avenir dans le domaine des réseaux de communication véhiculaires<br>The forthcoming sixth generation (6G) of wireless communication systems is expected to enable a wide range of new applications in vehicular communication, which is accompanied by a diverse set of challenges and opportunities resulting from the demands of this cutting-edge technology. In particular, these challenges arise from dynamic channel conditions, including time-varying channels and nonlinearities induced by high-power amplifiers. In this complex context, wireless channel estimation emerges as an essential element in establishing reliable communication. Furthermore, the potential of machine learning and deep learning in the design of receiver architectures adapted to vehicular communication networks is evident, given their capabilities to harness vast datasets, model complex channel conditions, and optimize receiver performance. Throughout the course of this research, we leveraged these potential tools to advance the state-of-the-art in receiver design for vehicular communication networks. In this manner, we delved into the characteristics of wireless channel estimation and the mitigation of nonlinear distortions, recognizing these as significant factors in the communication system performance. To this end, we propose new methods and flexible receivers, based on hybrid approaches that combine mathematical models and machine learning techniques, taking advantage of the unique characteristics of the vehicular channel to favor accurate estimation. Our analysis covers both conventional wireless communications waveform and a promising 6G waveform, targeting the comprehensiveness of our approach. The results of the proposed approaches are promising, characterized by substantial enhancements in performance and noteworthy reductions in system complexity. These findings hold the potential for real-world applications, marking a step toward the future in the domain of vehicular communication networks
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Kati, Efraim. "Fault-tolerant approach for deploying Server Agent-based Active Network Management (SAAM) server in Windows NT environment to provide uninterrupted services to routers in case of server failure(s)/." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA378563.
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