Dissertations / Theses: 'Position Base'

1

MACETTI, GIOVANNI. "TOPOLOGICAL DESCRIPTORS ENABLING NOVEL DISSECTIONS OF ELECTRON POSITION AND SPIN PROPERTIES IN COMPLEX MOLECULAR SYSTEMS." Doctoral thesis, Università degli Studi di Milano, 2019. http://hdl.handle.net/2434/615357.

Full text

Abstract:

Macroscopic and microscopic properties of molecular and solid-state systems are intimately related to the their electronic structure. The electron position and spin densities, which represent the probability distributions to find all or unpaired electrons in the space, contain information concerning several chemical-relevant properties, such as the chemical bonding and the magnetic behaviour. Understanding the fine atomic-level mechanism behind these properties is a key step to design chemical modifications to properly tune and develop materials or molecules with specific features. Topological descriptors can be used to extract information from these electron distributions. In this work, novel applications of the source function descriptor have been developed to gain further insights on the electron and spin density-related properties. These developments, together with other topological descriptors, were used to get further insights on relevant chemical systems. Firstly, the source function reconstruction was enlarged to a multi-dimensional grid of points with a particular focus on the two-dimensional maps. This analysis allows to see the ability of chosen subsets of atoms to reconstruct the density in the selected area within a cause-effect relationship and to rationalise the chemical or magnetic behaviours. The source function partial reconstructed maps depict if in a molecular region the atomic contributions are important, modest or negligible. Besides, they may also be useful for a proper selection of the reference points and for a full understanding of the source function percentages analysis. In fact, the choice of the reference point where to reconstruct the studied density is neither easy nor objective for non-standard situations, such as for the spin density. This novel application was applied to the study of the spin density on a couple of azido Cu complexes. The source function partial reconstructed maps allow to unravel the different role played by the paramagnetic centre Cu and the ligand atoms and to explain the spin transmission mechanism at a molecular level. Moreover, they enable to highlight the nature of the spin density differences between the two complexes and among adopted computational approaches. DFT functionals tend to over-delocalise the spin density towards the ligand atoms introducing a biased spin-polarization mechanism between the Cu and the ligand atoms. The same descriptor was then applied to the study of the hydrogen bonds in the DNA base pairs. The source function reveals the delocalised nature of these interactions, highlighting that distant groups and rings have non-negligible effects on the reconstruction of the electron density in the intermolecular region. Besides, the analysis demonstrates that the purine and pyrimidine bases equally contribute to the reconstruction of the electron density at the hydrogen bond critical points. The source function also reveals that subtle variations of the atomic source contributions occur when the pairs are ionized, revealing that sources and sinks effects redistribution plays an important role in the stabilization of the DNA base pairs. The source function was also used to develop a method to extract full population matrices purely based on the electron density distribution and then amenable to experimental determination. The peculiar features of this descriptor, in particular the cause-effect relationship, assign a profound chemical meaning to the matrix elements in contrast with other population analyses such as the Mulliken's one, where the matrix elements are associated to orbital overlaps. The latest breakthroughs on the development of this method are shown together with some numerical examples on very simple compounds. The full population matrices obtained using the source function descriptor are able to retrieve the major chemical features. A detailed analysis on the intermolecular interactions involved in the in vivo molecular recognition of the antimalarial drug chloroquine with the heme moiety has been carried out using a combined topological-energetic analysis. This work reveals that charged-assisted hydrogen bonds set up between the lateral chains of the chloroquine and the propionate group of the heme are the most important interactions in the drug:substrate recognition process.

APA, Harvard, Vancouver, ISO, and other styles

2

Hashemi, Amir. "Structure et compléxité des bases de Gröbner." Paris 6, 2006. http://www.theses.fr/2006PA066116.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Diao, Xunxing. "A resource-aware embedded commucation system for highly dynamic networks." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00715649.

Full text

Abstract:

Chaque année en Europe, 1.300.000 accidents de la route ont comme conséquence 1.700.000 blessés. Le coût financier d'accidents de la route est évalué à 160 milliards d'euros (approximativement le même coût aux Etats-Unis). VANET (Vehicular Ad-hoc NETwork) est une des technologies clés qui peut permettre de réduire d'une façon significative le nombre d'accidents de la route (e.g. message d'urgence signalant la présence d'un obstacle ou d'un véhicule en cas de brouillard). En plus de l'amélioration de la sécurité et du confort des conducteurs et des passagers, VANET peut contribuer à beaucoup d'applications potentielles telles que la prévision et la détection d'embouteillages, la gestion d'infrastructure de système de transport urbain (e.g. système de transport intelligent multimodal) etc. Dans cette thèse, je présenterai un système embarqué dédié à la communication inter-véhicule particulièrement pour les applications sécuritaires de passagers et de conducteurs. Nos efforts de recherche et de développement sont centrés sur deux principaux objectifs : minimiser le temps de latence intra-noeud et le délai de communication inter-véhicule en prenant en compte le changement dynamique du VANET. De ce fait pour atteindre ces objectifs, des nouvelles approches (e.g. inter-couche 'Cross-layering') ont été explorées pour respecter les contraintes de ressource (QoS, mémoire, CPU et énergie de la communication inter-véhicule) d'un système embarqué à faible coût. Le système de communication embarqué proposé comporte deux composants logiciels principaux : un protocole de communication dénommé CIVIC (Communication Inter Véhicule Intelligente et Coopérative) et un système d'exploitation temps réel appelé HEROS (Hybrid Event-driven and Real-time multitasking Operating System). CIVIC est un protocole de communication géographique à faible consommation énergétique et à faible temps de latence (délai de communication). HEROS gère contextuellement l'ensemble du système (matériel et logiciel) en minimisant le temps de latence et la consommation des ressources (CPU et mémoire). En outre, le protocole de communication CIVIC est équipé d'un système de localisation LCD-GPS (Low Cost Differential GPS). Pour tester et valider les différentes techniques et théories, la plateforme matérielle LiveNode (LImos Versatile Embedded wireless sensor NODE) a été utilisée. En effet, la plateforme LiveNode permet de développer et de prototyper rapidement des applications dans différents domaines. Le protocole de communication CIVIC est basé sur la technique de 'broadcast' à un saut ; de ce fait il est indépendant de la spécificité du réseau. Pour les expérimentations, seule la norme d'IEEE 802.15.4 (ZigBee) a été choisie comme médium d'accès sans fil. Il est à noter que le médium d'accès sans fil ZigBee a été adopté comme le médium standard pour les réseaux de capteurs sans fil (RCSFs) et le standard 6LoWPAN ; car il est peu coûteux et peu gourmand en énergie. Bien que le protocole de communication à l'origine soit conçu pour répondre aux exigences de VANET, ses domaines d'application ne sont pas limités à VANET. Par exemple il a été utilisé dans différents projets tels que MOBI+ (système de transport urbain intelligent) et NeT-ADDED (projet européen FP6 : agriculture de précision). Les VANETs et les RCSFs sont les réseaux fortement dynamiques, mais les causes de changement topologique de réseau sont différentes : dans le réseau VANET, il est dû à la mobilité des véhicules, et dans le RCSF, il est dû aux pannes des noeuds sans fil. Il est à noter que le VANET et le RCSF sont généralement considérés comme un sous-ensemble du réseau MANET (réseau ad-hoc mobile). Cependant, ils sont réellement tout à fait différents du MANET classique, et leurs similitudes et différences seront expliquées en détail dans la thèse. La contribution principale de mes travaux est le protocole CIVIC, qui échange des messages en basant sur l'information géographique des noeuds (position). Les travaux relatifs de la thèse se concentreront sur les techniques, les problèmes et les solutions de routage géographique, mais d'autres techniques de routage seront également adressées. Quelques projets relatifs au protocole de communication ont été étudiés mais leur implémentation et les aspects d'expérimentation n'ont pas été détaillés. Enfin la thèse ne présente pas simplement les techniques et concepts adoptés, et les résultats de simulation, mais en outre, elle expliquera les aspects techniques importants pour la réalisation et l'expérimentation des différentes applications ainsi que les résultats concrets obtenus.

APA, Harvard, Vancouver, ISO, and other styles

4

Muraro, Ana Paula. "Efeito da exposição ao tabagismo e da mobilidade social sobre o crescimento e ganho de peso do nascimento à adolescência em uma coorte de base populacional de Cuiabá-MT." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=6934.

Full text

Abstract:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Esta tese é composta por três artigos que permitiram avaliar o efeito da exposição ao tabagismo durante a gestação e no início da infância sobre o crescimento linear e ganho de peso do nascimento à adolescência, além de verificar o efeito do nível socioeconômico no início da infância e da mobilidade social sobre a adiposidade até a adolescência. Foram utilizados para este fim os dados de uma coorte de crianças nascidas entre 1994 e 1999 na cidade de Cuiabá-MT. Essas crianças fizeram parte de um estudo de base populacional realizado na cidade de Cuiabá, entre 1999 e 2000, com 2405 crianças (0 a 5 anos) e foram selecionadas aleatoriamente em unidades básicas de saúde quando da vacinação. As mães foram entrevistadas após a vacinação, quando foram obtidos dados relativos à exposição ao tabagismo gestacional, tabagismo passivo, nível socioeconômico das famílias e dados antropométricos. Entre 2009 e 2011, após aproximadamente 11 anos, essas crianças foram localizadas por meio do Censo Escolar e então 1716 adolescentes entre 10 e 17 anos de idade (71,4% da população) foram reavaliados nas escolas da rede pública e privada de Cuiabá, de 18 municípios do estado e outras 5 capitais do país. A análise por modelos lineares de efeitos mistos permitiu verificar a mudança de estatura e Índice de Massa Corporal (IMC) entre o nascimento e a adolescência. O primeiro e o segundo artigo desta tese avaliaram o efeito da exposição ao tabagismo materno durante a gestação e no início da infância sobre o crescimento linear e o IMC entre o nascimento e a adolescência. Crianças expostas ao tabagismo materno durante a gestação e no início da infância apresentaram menor estatura desde o nascimento até a adolescência quando comparadas às crianças não expostas. Quanto à adiposidade, entre o nascimento e a infância a mudança do IMC foi similar entre as crianças expostas e não expostas ao tabagismo materno, porém, entre a infância e a adolescência, aquelas expostas apenas durante a gestação mostraram maior ganho de IMC. Em conjunto, os dados corroboram o efeito deletério do tabagismo sobre o crescimento, efeito já bastante estudado, mas também indicam que avaliar e comparar exposição gestacional com pós-gestacional é importante, dado que seus efeitos parecem ser diferentes. O terceiro artigo avaliou o efeito do nível socioeconômico no início da infância e da mobilidade social entre a infância e a adolescência sobre o IMC do nascimento à adolescência. Para avaliar o nível socioeconômico, as famílias foram classificadas em nível econômico alto, médio e baixo, a partir do Critério de Classificação Econômica Brasil. Foi observada expressiva mobilidade social na população, principalmente entre os de menor nível econômico. Houve maior aumento do IMC entre o nascimento e a adolescência entre aqueles de maior nível econômico na infância e aqueles que permaneceram nas classes mais elevadas, indicando que a posição inicial foi o maior determinante das mudanças observadas no IMC. This thesis consists of three papers that allowed us to evaluate the effect of exposure to smoking during pregnancy and early childhood on linear growth and weight gain from birth to adolescence, and to verify the effect of socioeconomic position in early childhood and social mobility on adiposity until adolescence. For this purpose, we used the data of a cohort of children born between 1994 and 1999 in the city of Cuiabá. They were part of a population-based study conducted with 2,405 children (05 years) who attended one of the ten basic health units selected for vaccination in the city of Cuiabá between 1999 and 2000. Between 2009 and 2011, after approximately 11 years, these children were located through the School Census; thus, 1,716 adolescents aged 10 to 17 years old (71.4% of the population) were reassessed in the public and private schools of Cuiabá, of 18 counties in the state and five other capitals in the country. The mothers were interviewed after vaccination to obtain data regarding their exposure to smoking during pregnancy, passive smoking, socioeconomic status, and anthropometric information. The linear mixed-effects analysis showed the change in height and body mass index (BMI) from birth to adolescence. The first and second articles in this thesis evaluate the effect of exposure to maternal smoking during pregnancy and early childhood on linear growth and BMI from birth to adolescence. Children exposed to maternal smoking during pregnancy and early childhood were shorter from birth to adolescence than the children not exposed. As for adiposity between birth and childhood, the BMI change was similar between children exposed and not exposed to maternal smoking; however, between childhood and adolescence, those exposed only during gestation showed greater gains in BMI. Together, these data not only confirm the deleterious effect of smoking on growth, which has been extensively studied, but also indicate that it is important to evaluate and compare gestational to post-pregnancy exposure because their effects seem to be different. The third paper examines the effect of socioeconomic status in early childhood and social mobility from childhood to adolescence on BMI from birth to adolescence. To assess socioeconomic position, the families were classified into high, medium, and low economic levels based on the Brazil Criterion of economic classification. We observed significant social mobility in the population, especially among the lower economic group. We observed a greater increase in BMI from birth to adolescence among those from higher socioeconomic position in childhood and those who remained in the higher classes, indicating that the starting position was the major determinant of the observed changes in BMI.

APA, Harvard, Vancouver, ISO, and other styles

5

Berntsen, Per Ivar Barth. "Structural reliability based position mooring." Doctoral thesis, Norwegian University of Science and Technology, Department of Marine Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2134.

Full text

Abstract:

This thesis considers control of moored marine structures, referred to as position mooring. Moored marine structures can take on a number of different forms, and two applications are considered in this work, namely aquacultural farms and petroleum producing vessels. It is anticipated that future aquacultural farms will be significantly larger than the existing ones, and placed in much more exposed areas. Hence, there is a significant technology transfer potential between the two seemingly different fields of aquaculture and petroleum exploitation.Today’s implemented state of the art positioning controllers use predetermined safety regions and gain-scheduling for evaluating the necessary thruster force for the vessel to operate safely. This represents a suboptimal solution; the operator is given a significant number of variables to consider, and the thrusters are run more than necessary. Also, it is likely that a more conservative controller regime does not necessarily increase the overall reliability of the structure as compared with a less conservative but better designed controller.Motivated by this, a new control methodology and strategy for position mooring is developed. Two controllers using information about the reliability of the mooring system are implemented and tested, both via numerical simulations and model scale experiments. The first controller developed uses a reliability criterion based on the tension in the mooring system as a pretuning device. A nonlinear function based on the energy contained by the system is included in the controller to ensure that the thrusters are run only when needed. The controller is an output-feedback controller, based on measurement of position and estimated values of the velocities and slowly varying environmental loads. The second controller developed contains the reliability criterion intrinsically, thus, less pretuning is needed. The backstepping technique is applied during the design process, and the controller has global asymptotical stability properties.

APA, Harvard, Vancouver, ISO, and other styles

6

Araújo, Filipe. "Position-Based Distributed Hash Tables." Doctoral thesis, Department of Informatics, University of Lisbon, 2006. http://hdl.handle.net/10451/14297.

Full text

Abstract:

In this thesis we want to create scalable, fault-tolerant and self-configuring dictionaries that can be deployed in a wide range of networks, including highly dynamic networks with frequent membership changes, like peer-to-peer overlay networks or wireless ad hoc networks. In recent years, distributed hash tables (DHTs) have emerged as a solution to implement large-scale dictionaries. However, given the existing bandwidth limitations, updating routing information in DHTs remains a challenge. Position-based routing schemes arise as an attractive solution to this problem, due to inexpensive and ubiquitous localization mechanisms. Positional information enables the creation of oblivious (or memoryless) routing schemes, where the coordinates of the current forwarding node, of its neighbors and of the destination, suffice to determine the next hop. Such routing schemes are very suitable to rapidly changing networks, because they require very little control information. We argue in this thesis that we can use positional information to efficiently support routing and DHT operation in wireless ad hoc and in wired networks, whenever position of nodes reflects network topology. To support this claim, we create and evaluate a number of algorithms that simultaneously support routing and DHT operation in both types of networks. % As an interesting result of our work, we can combine solutions into a single architecture that spans wired and wireless networks. This architecture can provide a seamless integration and use of a position-based DHT, despite the access network of the peer nodes

APA, Harvard, Vancouver, ISO, and other styles

7

Coombe, Duncan David. "Secure Base Leadership: A Positive Theory of Leadership Incorporating Safety, Exploration and Positive Action." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1270505789.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Shilpiekandula, Vijay 1979. "A laser speckle based position sensing technique." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/27131.

Full text

Abstract:

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004. Includes bibliographical references (p. 129-131). This thesis presents the design and development of a novel laser-speckle-based position sensing technique. In our prototype implementation, a He-Ne laser beam is directed at the surface of an air-bearing spindle. An imaging system is set up to capture speckle patterns scattered from the spindle surface. These patterns are highly correlated over small angular displacements of the spindle. We use correlation-based image-processing algorithms to measure offsets between the speckle patterns. These offsets are calibrated against the counts of a commercial incremental optical encoder. A custom-built bicell photointerrupter unit is used as a reference sensor for the incremental optical encoder. To test for the control performance of this speckle-based sensor, we have constructed a transmission drive to run the air-bearing spindle. Our speckle-based metrology system is able to run at update rates of 10 Hz with a measured closed loop -3 dB bandwidth of about 2 Hz. Using a real-time processor interfaced with a desktop PC, we have implemented a novel algorithm that interpolates position estimates with respect to two pre-stored global images. We predict that this technique can potentially achieve resolutions of 0.1 [mu]m for translational and 5 [mu]rad for rotational motion. The limitation of our current implementation is the low update rates resulting from the time-intensive nature of correlation-based methods. Possible methods to overcome this limitation are addressed and ideas for follow-on work are presented. by Vijay Shilpiekandula. S.M.

APA, Harvard, Vancouver, ISO, and other styles

9

Vieira, Miguel Castro Miguéis. "VLC based position etimation for robotic navigation." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/21666.

Full text

Abstract:

Mestrado em Engenharia Eletrónica e Telecomunicações Resumo não disponível The widespread use of LED as arti cial illumination lead to the development of indoor positioning systems using visible light. On this work we gathered information on strategies and sensors used in visible light positioning (VLP). As such, we propose to estimate a robots position based on visible light communication (VLC) using a prototype developed in previous works. The work was divided in four stages. Initially, we veri ed that the prototype used was suitable to estimate its position. In order to overcome the prototype's limitations, a simulation environment was developed, where similar structures were tested. This allowed the comparison between the results obtained using the prototype and those from the simulator. At last, a noise model was implemented on the simulator to verify its in uence on the position estimation. The results show the viability of implementing VLP using a simple sensor based on a set of photo-diodes placed over a hemispherical dome, yielding a low-cost solution for VLP. When comparing the results obtained with the prototype and the simulator, we veri ed that the response is identical. With the implementation of the noise model, the results show an error of a few centimetres. We concluded that the photo-diodes eld of view is important when the position is estimated. The sensors eld of view should be big enough to intercept others in order to prevent blind spots but not too big since it would lead to errors because all sensors would receive signal.

APA, Harvard, Vancouver, ISO, and other styles

10

Adams, Douglas Edward. "A high resolution capacitance-based lateral position microsensor." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/46050.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Transier, Matthias. "Position-based multicast for mobile ad-hoc networks." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:180-madoc-20209.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

WIERSMA, JOSHUA THOMAS. "MOUSE-OPTICS BASED POSITION MEASUREMENT AND DISPLAY SYSTEM." Thesis, The University of Arizona, 2008. http://hdl.handle.net/10150/192254.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Blaskovic, Kraljevic Neven. "Development of a high-precision low-latency position feedback system for single-pass beamlines using stripline and cavity beam position monitors." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:0286d951-d177-4d3a-8bce-a50e6ccb8645.

Full text

Abstract:

The FONT beam-based, intra-train feedback system has been designed to provide beam stability at single-pass accelerators, such as at the interaction point (IP) of the International Linear Collider. Two FONT feedback systems have been commissioned at the Accelerator Test Facility (ATF) at KEK, Japan, and the operation, optimisation and performance of these systems is the subject of this thesis. For each system, the accelerator is operated with two-bunch trains with a bunch separation of around 200 ns, allowing the first bunch to be measured and the second bunch to be subsequently corrected. The first system consists of a coupled-loop system in which two stripline beam position monitors (BPMs) are used to characterise the incoming beam position and angle, and two kickers are used to stabilise the beam. A BPM resolution of about 300 nm has been measured. On operating the feedback system, a factor ~ 3 reduction in position jitter has been demonstrated at the feedback BPMs and the successful propagation of this correction to a witness BPM located 30 m downstream has been confirmed. The second system makes use of a beam position measurement at the ATF IP that is used to drive a kicker to provide a local correction. The measurement is performed using a high-resolution cavity BPM with a fast decay time of around 20 ns designed to allow multiple bunches to be resolved. The linearity of the cavity BPM system and the noise floor of the electronics are discussed in detail. The performance of the BPM system under standard ATF operation and with the beam waist at the BPM is described. A BPM resolution of about 50 nm has been measured. This IP feedback system has been used to stabilise the beam position to the 75 nm level.

APA, Harvard, Vancouver, ISO, and other styles

14

Liong, Choong Yeun. "Investigation of vision based system for passenger position recognition." Thesis, Cranfield University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393621.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Jäkel, Tobias, Martin Weißbach, Kai Herrmann, Hannes Voigt, and Max Leuthäuser. "Position paper: Runtime Model for Role-based Software Systems." IEEE, 2016. https://tud.qucosa.de/id/qucosa%3A75302.

Full text

Abstract:

In the increasingly dynamic realities of today's software systems, it is no longer feasible to always expect human developers to react to changing environments and changing conditions immediately. Instead, software systems need to be self-aware and autonomously adapt their behavior according to their experiences gathered from their environment. Current research provides role-based modeling as a promising approach to handle the adaptivity and self-awareness within a software system. There are established role-based systems e.g., for application development, persistence, and so on. However, these are isolated approaches using the role-based model on their specific layer and mapping to existing non-role-based layers. We present a global runtime model covering the whole stack of a software system to maintain a global view of the current system state and model the interdependencies between the layers. This facilitates building holistic role-based software systems using the role concept on every single layer to exploit its full potential, particularly adaptivity and self-awareness.

APA, Harvard, Vancouver, ISO, and other styles

16

Noureddine, Hadi. "Position-based routing and MAC protocols for wireless ad-hoc networks." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/5834.

Full text

Abstract:

This thesis presents the Forecasting Routing Technique (FORTEL), a routing protocol for Mobile Ad-Hoc Networks (MANETs) based on the nodes' Location Information. FORTEL stores the nodes' location information in the Location Table (LT) in order to construct routes between the source and the destination nodes. FORTEL follows the source routing strategy, which has rarely been applied in position-based routing. According to the source routing strategy, the end-to-end route is attached to the packet, therefore, the processing cost, in regards to the intermediate nodes that simply relay the packet according to route, is minimized. FORTEL's key mechanisms include: first, the location update scheme, employed to keep the LT entries up-to-date with the network topology. Besides the mobility variation and the constant rate location update schemes applied, a window location update scheme is presented to increase the LT's information accuracy. Second, the switching mechanism, between "Hello" message and location update employed, to reduce the protocol's routing overhead. Third and most important is the route computation mechanism, which is integrated with a topology forecasting technique to construct up-to-date routes between the communication peers, aiming to achieve high delivery rate and increase the protocol robustness against the nodes' movement. FORTEL demonstrates higher performance as compared to other MANET's routing protocols, and it delivers up to 20% more packets than AODV and up to 60 % more than DSR and OLSR, while maintaining low levels of routing overhead and network delay at the same time. The effectiveness of the window update scheme is also discussed, and it proves to increase FORTEL's delivery rate by up to 30% as compared to the other update schemes. A common and frequently occurring phenomenon, in wireless networks, is the Hidden Terminal problem that significantly impacts the communication performance and the efficiency of the routing and MAC protocols. Beaconless routing approach in MANETs, which delivers data packets without prior knowledge of any sort `of information, suffers from packet duplication caused by the hidden nodes during the contention process. Moreover, the throughput of the IEEE MAC protocol decreases dramatically when the hidden terminal problem occurs. RTS/CTS mechanism fails to eliminate the problem and can further degrade the network's performance by introducing additional overhead. To tackle these challenges, this thesis presents two techniques, the Sender Suppression Algorithm and the Location-Aided MAC, where both rely on the nodes' position to eliminate packet duplication in the beaconless routing and improve the performance of the 802.11 MAC respectively. Both schemes are based on the concept of grouping the nodes into zones and assign different time delay to each one. According to the Sender Suppression Algorithm, the sender's forwarding area is divided into three zones, therefore, the local timer, set to define the time that the receiver has to wait before responding to the sender's transmission, is added to the assigned zone delay. Following the first response, the sender interferes and suppresses the receivers with active timer of. On the other hand, the Location-Aided MAC, essentially a hybrid MAC, combines the concepts of time division and carrier sensing. The radio range of the wireless receiver is partitioned into four zones with different zone delays assigned to each zone. Channel access within the zone is purely controlled by CSMA/CA protocol, while it is time-based amongst zones. The effectiveness of the proposed techniques is demonstrated through simulation tests. Location-Aided MAC considerably improves the network's throughput compared to CSMA/CA and RTS/CTS. However, remarkable results come when the proposed technique and the RTS/CTS are combined, which achieves up to 20% more throughput as compared to the standalone RTS/CTS. Finally, the thesis presents a novel link lifetime estimation method for greedy forwarding to compute the link duration between two nodes. Based on a newly introduced Stability-Aware Greedy (SAG) scheme, the proposed method incorporates the destination node in the computation process and thus has a significant advantage over the conventional method, which only considers the information of the nodes composing the link.

APA, Harvard, Vancouver, ISO, and other styles

17

Lund, Kasey Roy. "Van de Graaff based positron source production." Thesis, Washington State University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3732705.

Full text

Abstract:

The anti-matter counterpart to the electron, the positron, can be used for a myriad of different scientific research projects to include materials research, energy storage, and deep space flight propulsion. Currently there is a demand for large numbers of positrons to aid in these mentioned research projects. There are different methods of producing and harvesting positrons but all require radioactive sources or large facilities. Positron beams produced by relatively small accelerators are attractive because they are easily shut down, and small accelerators are readily available. A 4MV Van de Graaff accelerator was used to induce the nuclear reaction 12C(d,n)13N in order to produce an intense beam of positrons. 13N is an isotope of nitrogen that decays with a 10 minute half life into 13C, a positron, and an electron neutrino. This radioactive gas is frozen onto a cryogenic freezer where it is then channeled to form an antimatter beam. The beam is then guided using axial magnetic fields into a superconducting magnet with a field strength up to 7 Tesla where it will be stored in a newly designed Micro-Penning-Malmberg trap. Several source geometries have been experimented on and found that a maximum antimatter beam with a positron flux of greater than 0.55×10 6 e+s-1 was achieved. This beam was produced using a solid rare gas moderator composed of krypton. Due to geometric restrictions on this set up, only 0.1-1.0% of the antimatter was being frozen to the desired locations. Simulations and preliminary experiments suggest that a new geometry, currently under testing, will produce a beam of 107 e+s-1 or more.

APA, Harvard, Vancouver, ISO, and other styles

18

Jenkins, Michael. "Novel designs for undulator based positron sources." Thesis, Lancaster University, 2015. http://eprints.lancs.ac.uk/76604/.

Full text

Abstract:

Proposed high energy electron-positron linear colliders require a high ux of positrons. To achieve this a number of new positron source designs have been proposed. One of these is an undulator-based positron source, which is the baseline positron source design for the International Linear Collider. The undulator-based positron source for the International Linear Collider uses a helical undulator to produce a intense photon beam that generates positrons through the pairproduction mechanism. As a helical undulator is used the photon beam is polarised and this results in polarised positrons being produced. This thesis investigates the undulator-based positron source design and aims to optimise it for positron production at the International Linear Collider. To do this the undulator is studied in detail as there is a large scope to design a bespoke undulator for positron production. As the particle physics community is interested in having a high positron polarisation the undulatorbased positron source needs to be optimised for yield and polarisation. In order to optimise the design of the helical undulator we derive an analytical equation for the radiation produced by a helical undulator. This is done to provide some understanding of how the dierent undulator parameters aect the photon spectrum produced by a helical undulator. In addition to the analytical equation, new software is used to calculate the photon spectra produced by non-ideal undulators in order to evaluate how a realistic undulator-based positron source would function. Using suggestions proposed in this thesis we could expect to see an increase in positron yield of of 10:9% and an increase in positron polarisation from 21:93% to 41:93 %.

APA, Harvard, Vancouver, ISO, and other styles

19

Pascucci, Fiammetta. "A Positon Based Approach to Ragdoll Simulation." Thesis, Linköping University, Department of Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-9396.

Full text

Abstract:

Create the realistic motion of a character is a very complicated work.This thesis aims to create interactive animation for characters in three dimensions using position based approach. Our character is pictured from ragdoll, which is a structure of system particles where all particles are linked by equidistance constraints.The goal of this thesis is observed the fall in the space of our ragdoll after creating all constraints, as structure, contact and environment constraints.The structure constraint represents all joint constraints which have one, two or three Degree of Freedom (DOF).The contact constraints are represented by collisions between our ragdoll and other objects in the space.Finally, the environment constraints are represented by means of the wall constraint.The achieved results allow to have a realist fall of our ragdoll in the space.

APA, Harvard, Vancouver, ISO, and other styles

20

Rojas, Nicolàs. "Distance-based formulations for the position analysis of kinematic chains." Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/83516.

Full text

Abstract:

This thesis addresses the kinematic analysis of mechanisms, in particular, the position analysis of kinematic chains, or linkages, that is, mechanisms with rigid bodies (links) interconnected by kinematic pairs (joints). This problem, of completely geometrical nature, consists in finding the feasible assembly modes that a kinematic chain can adopt. An assembly mode is a possible relative transformation between the links of a kinematic chain. When an assignment of positions and orientations is made for all links with respect to a given reference frame, an assembly mode is called a configuration. The methods reported in the literature for solving the position analysis of kinematic chains can be classified as graphical, analytical, or numerical. The graphical approaches are mostly geometrical and designed to solve particular problems. The analytical and numerical methods deal, in general, with kinematic chains of any topology and translate the original geometric problem into a system of kinematic analysis of all the Assur kinematic chains resulting from replacing some of its revolute joints by slider joints. Thus, it is concluded that the polynomials of all fully-parallel planar robots can be derived directly from that of the widely known 3-RPR robot. In addition to these results, this thesis also presents an efficient procedure, based on distance and oriented area constraints, and geometrical arguments, to trace coupler curves of pin-jointed Gr¨ubler kinematic chains. All these techniques and results together are contributions to theoretical kinematics of mechanisms, robot kinematics, and distance plane geometry. equations that defines the location of each link based, mainly, on independent loop equations. In the analytical approaches, the system of kinematic equations is reduced to a polynomial, known as the characteristic polynomial of the linkage, using different elimination methods —e.g., Gr¨obner bases or resultant techniques. In the numerical approaches, the system of kinematic equations is solved using, for instance, polynomial continuation or interval-based procedures. In any case, the use of independent loop equations to solve the position analysis of kinematic chains, almost a standard in kinematics of mechanisms, has seldom been questioned despite the resulting system of kinematic equations becomes quite involved even for simple linkages. Moreover, stating the position analysis of kinematic chains directly in terms of poses, with or without using independent loop equations, introduces two major disadvantages: arbitrary reference frames has to be included, and all formulas involve translations and rotations simultaneously. This thesis departs from this standard approach by, instead of directly computing Cartesian locations, expressing the original position problem as a system of distance-based constraints that are then solved using analytical and numerical procedures adapted to their particularities. In favor of developing the basics and theory of the proposed approach, this thesis focuses on the study of the most fundamental planar kinematic chains, namely, Baranov trusses, Assur kinematic chains, and pin-jointed Gr¨ubler kinematic chains. The results obtained have shown that the novel developed techniques are promising tools for the position analysis of kinematic chains and related problems. For example, using these techniques, the characteristic polynomials of most of the cataloged Baranov trusses can be obtained without relying on variable eliminations or trigonometric substitutions and using no other tools than elementary algebra. An outcome in clear contrast with the complex variable eliminations require when independent loop equations are used to tackle the problem. The impact of the above result is actually greater because it is shown that the characteristic polynomial of a Baranov truss, derived using the proposed distance-based techniques, contains all the necessary and sufficient information for solving the position Esta tesis aborda el problema de análisis de posición de cadenas cinemáticas, mecanismos con cuerpos rígidos (enlaces) interconectados por pares cinemáticos (articulaciones). Este problema, de naturaleza geométrica, consiste en encontrar los modos de ensamblaje factibles que una cadena cinemática puede adoptar. Un modo de ensamblaje es una transformación relativa posible entre los enlaces de una cadena cinemática. Los métodos reportados en la literatura para la solución del análisis de posición de cadenas cinemáticas se pueden clasificar como gráficos, analíticos o numéricos. Los enfoques gráficos son geométricos y se diseñan para resolver problemas particulares. Los métodos analíticos y numéricos tratan con cadenas cinemáticas de cualquier topología y traducen el problema geométrico original en un sistema de ecuaciones cinemáticas que define la ubicación de cada enlace, basado generalmente en ecuaciones de bucle independientes. En los enfoques analíticos, el sistema de ecuaciones cinemáticas se reduce a un polinomio, conocido como el polinomio característico de la cadena cinemática, utilizando diferentes métodos de eliminación. En los métodos numéricos, el sistema se resuelve utilizando, por ejemplo, la continuación polinomial o procedimientos basados en intervalos. En cualquier caso, el uso de ecuaciones de bucle independientes, un estándar en cinemática de mecanismos, rara vez ha sido cuestionado a pesar de que el sistema resultante de ecuaciones es bastante complicado, incluso para cadenas simples. Por otra parte, establecer el análisis de la posición de cadenas cinemáticas directamente en términos de poses, con o sin el uso de ecuaciones de bucle independientes, presenta dos inconvenientes: sistemas de referencia arbitrarios deben ser introducidos, y todas las fórmulas implican traslaciones y rotaciones de forma simultánea. Esta tesis se aparta de este enfoque estándar expresando el problema de posición original como un sistema de restricciones basadas en distancias, en lugar de directamente calcular posiciones cartesianas. Estas restricciones son posteriormente resueltas con procedimientos analíticos y numéricos adaptados a sus particularidades. Con el propósito de desarrollar los conceptos básicos y la teoría del enfoque propuesto, esta tesis se centra en el estudio de las cadenas cinemáticas planas más fundamentales, a saber, estructuras de Baranov, cadenas cinemáticas de Assur, y cadenas cinemáticas de Grübler. Los resultados obtenidos han demostrado que las técnicas desarrolladas son herramientas prometedoras para el análisis de posición de cadenas cinemáticas y problemas relacionados. Por ejemplo, usando dichas técnicas, los polinomios característicos de la mayoría de las estructuras de Baranov catalogadas se puede obtener sin realizar eliminaciones de variables o sustituciones trigonométricas, y utilizando solo álgebra elemental. Un resultado en claro contraste con las complejas eliminaciones de variables que se requieren cuando se utilizan ecuaciones de bucle independientes. El impacto del resultado anterior es mayor porque se demuestra que el polinomio característico de una estructura de Baranov, derivado con las técnicas propuestas, contiene toda la información necesaria y suficiente para resolver el análisis de posición de las cadenas cinemáticas de Assur que resultan de la sustitución de algunas de sus articulaciones de revolución por articulaciones prismáticas. De esta forma, se concluye que los polinomios de todos los robots planares totalmente paralelos se pueden derivar directamente del polinomio característico del conocido robot 3-RPR. Adicionalmente, se presenta un procedimiento eficaz, basado en restricciones de distancias y áreas orientadas, y argumentos geométricos, para trazar curvas de acoplador de cadenas cinemáticas de Grübler. En conjunto, todas estas técnicas y resultados constituyen contribuciones a la cinemática teórica de mecanismos, la cinemática de robots, y la geometría plana de distancias. Barcelona 13-

APA, Harvard, Vancouver, ISO, and other styles

21

Blattes, Roxane. "BASES MOLECULAIRES DE LA VARIEGATION D'EFFETDE POSITION CHEZ DROSOPHILA MELANOGASTER." Phd thesis, Université Paul Sabatier - Toulouse III, 2006. http://tel.archives-ouvertes.fr/tel-00107128.

Full text

Abstract:

Les séquences satellites III (SATIII) représentent la majeure partie de l'hétérochromatine du chromosome X de drosophile et jouent un rôle dans la variégation d'effet de position du gène white dans l'inversion white-mottled. Leurs caractéristiques structurales dues à leur richesse en dA•dT sont ciblées par des ligands synthétiques du petit sillon de l'ADN, outils qui ont permis de caractériser la fonction des SATIII dans l'assemblage de l'hétérochromatine. Nous avons mis en évidence un rôle de D1, qui reconnaît spécifiquement les SATIII, mais aussi de la topoïsomérase II, dans l'initiation de l'assemblage de l'hétérochromatine. Nos résultats suggèrent que les SATIII pourraient constituer un réservoir de protéines servant à la régulation de la transcription du locus des gènes ribosomiques (rDNA) adjacent aux SATIII. Enfin, nous avons pu identifier un élément frontière qui contrôle le cloisonnement de l'hétérochromatine et jouerait un rôle dans la régulation de l'expression du rDNA

APA, Harvard, Vancouver, ISO, and other styles

22

Chuckpaiwong, Ittichote. "Development of position sensor using phase-based continuous wave radar." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/20505.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Sheridan, Kevin Francis. "GPS based position and attitude determination for airborne remote sensing." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271175.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Worley, John. "Auditory attention based on differences in median vertical plane position." Thesis, University of Sussex, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289221.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Frini, Marouane. "Diagnostic des engrenages à base des indicateurs géométriques des signaux électriques triphasés." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSES052.

Full text

Abstract:

Bien qu’ils soient largement utilisés dans le domaine, les mesures vibratoires classiques présentent plusieurs limites. A la base, l’analyse vibratoire ne peut identifier qu’environ 60% des défauts qui peuvent survenir dans les machines. Cependant, les principaux inconvénients des mesures de la vibration sont l’accès difficile au système de transmission afin d’y placer le capteur ainsi que le coût conséquent de la mise en œuvre. Ceci résulte en des problèmes de sensibilité relatifs à la position de l’installation et ceux de difficulté pour distinguer la source de vibration à cause de la diversité des excitations mécaniques qui existent dans l’environnement industriel.Par conséquent, l’analyse des signatures du courant électrique des moteurs s’impose comme une alternative prometteuse à l’analyse vibratoire et a donc fait l’objet d’une attention grandissante au cours des dernières années. En effet, l’analyse des signatures électriques a l’avantage d’être une méthode techniquement accessible, non-intrusive au système et peu coûteuse. Les techniques basées sur le courant et la tension ne requièrent que les mesures électriques du moteur qui sont souvent déjà surveillées pour le contrôle et la protection des machines électriques. Ce processus a été principalement utilisé pour la détection des défauts de moteur tels que la rupture de barres du rotor et les défauts d’excentricité ainsi que les défauts de roulements. En revanche, très peu de recherches concernent la détection des défauts en utilisant l’analyse du courant. En outre, les signaux électriques triphasés sont caractérisés par des représentations géométriques particulières liées à leur forme d’onde qui peuvent servir en tant qu’indicateurs différents offrant des informations supplémentaires. Parmi ces indicateurs géométriques, les transformées de Park et de Concordia modélisent les composantes électriques dans un repère bidimensionnel et toute déviation par rapport à la représentation d’origine indique l’apparition d’un dysfonctionnement. Aussi, les équations différentielles de Frenet-Serret représentent la trajectoire du signal dans un espace euclidien tridimensionnel et indiquent ainsi tout changement dans l’état du système. Bien qu’ils aient été utilisés pour les défauts de roulements, ces indicateurs n’ont pas été appliqués dans la détection des défauts d’engrenages en utilisant l’analyse des signatures des courants électriques. D’où l’idée novatrice de combiner ces indicateurs avec des techniques de traitement de signal, ainsi que des techniques de classification pour le diagnostic des engrenages en utilisant l’analyse des signatures de courant et de tension du moteur électrique.Ainsi, dans ce travail, on propose une nouvelle approche pour le diagnostic des défauts d’engrenages en utilisant l’analyse des courants et des tensions électriques du stator de la machine et ceci en se basant sur un ensemble d’indicateurs géométriques (Transformées de Park et de Concordia ainsi que les propriétés du repère Frenet-Serret). Ces indicateurs font partie d’une bibliothèque de signatures de défauts qui a été construite et qui comprend également les indicateurs classiques utilisés pour un large éventail de défauts. Ainsi, un algorithme combine les acquisitions expérimentales des signaux électriques à des méthodes de traitement de signal avancées (décomposition modale empirique,…). Ensuite, celui-ci sélectionne les indicateurs les plus pertinents au sein de la bibliothèque en se basant sur les algorithmes de sélection de paramètres (sélection séquentielle rétrograde et analyse des composantes principales). Enfin, cette sélection est utilisée pour la classification non-supervisée (K-moyennes) pour la distinction entre l’état sain et l’état défaillant Although they are widely used, classical vibration measurements have several limitations. Vibration analysis can only identify about 60% of the defects that may occur in mechanical systems. However, the main drawbacks of vibration measurements are the difficult access to the transmission system in order to place the sensor as well as the consequent cost of implementation. This results in sensitivity problems relative to the position of the installation and the difficulty to distinguish the source of vibration because of the diversity of mechanical excitations that exist in the industrial environment.Hence, the Motor Current Signatures Analysis (M.C.S.A.) represents a promising alternative to the vibration analysis and has therefore been the subject of increasing attention in recent years. Indeed, the analysis of electrical signatures has the advantage of being a technically accessible method as well as inexpensive and non-intrusive to the system. Techniques based on currents and voltages only require the motor’s electrical measurements which are often already supervised for the purposes of the control and the protection of the electrical machines. This process was mainly used for the detection of motors faults such as rotor bars breakage and eccentricity faults as well as bearings defects. On the other hand, very little research has been focused on gear faults detection using the current analysis. In addition, three-phase electrical signals are characterized by specific geometric representations related to their waveforms and they can serve as different indicators providing additional information. Among these geometric indicators, the Park and Concordia transforms model the electrical components in a two-dimensional coordinate system and any deviation from the original representation indicates the apparition of a malfunction. Moreover, the differential equations of Frenet-Serret represent the trajectory of the signal in a three-dimensional euclidean space and thus indicate any changes in the state of the system. Although they have been previously used for bearing defects, these indicators have not been applied in the detection of gear defects using the analysis of electrical current signatures. Hence, the innovative idea of combining these indicators with signal processing techniques, as well as classification techniques for gears diagnosis using the three-phase motor’s electrical current signatures analysis is established.Hence, in this work, a new approach is proposed for gear faults diagnosis using the motor currents analysis, based on a set of geometric indicators (Park and Concordia transforms as well as the properties of the Frenet-Serret frame). These indicators are part of a specifically built fault signatures library and which also includes the classical indicators used for a wide range of faults. Thus, a proposed estimation algorithm combines experimental measurements of electrical signals with advanced signal processing methods (Empirical Mode Decomposition, ...). Next, it selects the most relevant indicators within the library based on feature selection algorithms (Sequential Backward Selection and Principal Component Analysis). Finally, this selection is combined with non-supervised classification (K-means) for the distinction between the healthy state and faulty states. It was finally validated with a an additional experimental configuration in different cases with gear faults, bearing faults and combined faults with various load levels

APA, Harvard, Vancouver, ISO, and other styles

26

Taylor, James Williams. "Positron annihilation spectroscopy applied to silicon-based materials." Thesis, Royal Holloway, University of London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394376.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Hamad, Sofian. "Efficient route discovery for reactive routing." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/7634.

Full text

Abstract:

Information on the location of mobile nodes in Mobile Ad-hoc Networks (MANETs) has the potential to significantly improve network performance. This thesis uses node location information to develop new techniques for route discovery in on-demand routing protocols such as the Ad-hoc On-Demand Distance Vector (AODV), thus making an important contribution to enhancing the experience of using mobile networks. A Candidate Neighbours to Rebroadcast the Route Request (CNRR) approach has been proposed to reduce the deleterious impact, known as the broadcast storm, of RREQ packets flooding in traditional on-demand routing protocols. The main concept behind CNRR is specifying a set of neighbours which will rebroadcast the received RREQ. This is a departure from the traditional approach of all receiving nodes rebroadcasting RREQs and has the effect of reducing the problem of redundancy from which mobile networks suffer. The proposed protocol has been developed in two phases: Closest-CNRR and Furthest-CNRR. The simulation results show that the proposed algorithms have a significant effect as they reduce the routing overhead of the AODV protocol by up to 28% compared to the C-CNRR, and by up to 17.5% compared to the F-CNRR. Notably, the proposed algorithms simultaneously achieve better throughput and less data dropping. The Link Stability and Energy Aware protocol (LSEA) has been developed to reduce the overhead while increasing network lifetimes. The LSEA helps to control the global dissemination of RREQs in the network by eliminating those nodes that have a residual energy level below a specific threshold value from participation in end-to-end routes. The proposed LSEA protocol significantly increases network lifetimes by up to 19% compared with other on-demand routing protocols while still managing to obtain the same packet delivery ratio and network throughput levels. Furthermore, merging the LSEA and CNRR concepts has the great advantage of reducing the dissemination of RREQs in the network without loss of reachability among the nodes. This increases network lifetimes, reduces the overhead and increases the amount of data sent and received. Accordingly, a Position-based Selective Neighbour (PSN) approach has been proposed which combines the advantages of zoning and link stability. The results show that the proposed technique has notable advantages over both the AODV and MAAODV as it improves delivery ratios by 24.6% and 18.8%, respectively.

APA, Harvard, Vancouver, ISO, and other styles

28

Katkus, Kęstutis. "Hibridinis genetinis algoritmas komivojažieriaus uždaviniui." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2006. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2006~D_20060606_203011-23232.

Full text

Abstract:

In this work, the Traveling Salesman Problem (TSP) is discussed. The Hybrid Genetic Algorithm for solving the TSP is presented. The traveling salesman problem is formulated as follows: given matrix D=(dij)nxn of distances between n objects and the set P of permutations of the integers from 1 to n, find a permutation p=(p(1), p(2), ..., p(n)) P that minimizes. Many heuristic algorithms can be applied for the TSP. Recently, genetic algorithms (GAs) are among the advanced heuristic techniques for the combinatorial problems, like the TSP. genetic algorithms are based on the biological process of natural selection. The original concepts of GAs were developed in 1970s. Many simulations have demonstrated the efficiency of GAs on different optimization problems, among them, bin–packing, generalized assignment problem, graph partitioning, job–shop scheduling problem, set covering problem, vehicle routing. One of the main operators in GAs is the crossover (i.e. solution recombination). This operator plays a very important role by constructing competitive GAs. In this work, we investigate several crossover operators for the TSP, among them, CX (cycle crossover), PMX (partialy mapped crossover), POS (position based crossover), ER (edge recombination crossover), edge-NN (edge recombination crossover, nearest neighbour) and AP (alternating-positions crossover). Comparison of these crossover operators was performed. The results show high efficiency of the edge-NN, ER and PMX crossovers.

APA, Harvard, Vancouver, ISO, and other styles

29

Salazar, Hernández Dagoberto José. "Precise GPS-based position, velocity and acceleration determination: algorithms and tools." Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/77654.

Full text

Abstract:

Esta tesis doctoral llevó a cabo el estudio, desarrollo e implementación de algoritmos para la navegación con sistemas globales de navegación por satélite (GNSS), enfocándose en la determinación precisa de la posición, velocidad y aceleración usando GPS, en modo post-procesado y lejos de estaciones de referencia. Uno de los objetivos era desarrollar herramientas en esta área y hacerlas disponibles a la comunidad GNSS. Por ello el desarrollo se hizo dentro del marco del proyecto preexistente de software libre llamado GPS Toolkit (GPSTk). Una de las primeras tareas realizadas fue la validación de las capacidades de la GPSTk para el procesado del pseudorango, realizando comparaciones con una herramienta de procesamiento de datos probada (BRUS). La gestión de datos GNSS demostró ser un asunto importante cuando se intentó extender las capacidades de la GPSTk al procesamiento de datos obtenidos de las fases de la señal GPS. Por ello se desarrollaron las Estructuras de Datos GNSS (GDS), que combinadas con su paradigma de procesamiento aceleran el proceso de desarrollo de software y reducen errores. La extensión de la GPSTk a los algoritmos de procesado en fase se hizo mediante la ayuda de las GDS, proporcionándose importantes clases accesorias que facilitan el trabajo. Se implementó el procesado de datos Precise Point Positioning (PPP) con ejemplos relativamente simples basados en las GDS, y al comparar sus resultados con otras aplicaciones de reputación ya establecida, se encontró que destacan entre los mejores. También se estudió cómo obtener la posición precisa, en post-proceso, de un receptor GPS a cientos de kilómetros de la estación de referencia más cercana y usando tasas de datos arbitrarias (una limitación del método PPP). Las ventajas aportadas por las GDS permitieron la implementación de un procesado semejante a un PPP cinemático basado en una red de estaciones de referencia, estrategia bautizada como Precise Orbits Positioning (POP) porque sólo necesita órbitas precisas para trabajar y es independiente de la información de los relojes de los satélites GPS. Los resultados de este enfoque fueron muy similares a los del método PPP cinemático estándar, pero proporcionando soluciones de posición con una tasa mayor y de manera más robusta. La última parte se enfocó en la implementación y mejora de algoritmos para determinar con precisión la velocidad y aceleración de un receptor GPS. Se hizo énfasis en el método de las fases de Kennedy debido a su buen rendimiento, desarrollando una implementación de referencia y demostrando la existencia de una falla en el procedimiento propuesto originalmente para el cálculo de las velocidades de los satélites. Se propuso entonces una modificación relativamente sencilla que redujo en un factor mayor que 35 el RMS de los errores 3D en velocidad. Tomando ideas de los métodos Kennedy y POP se desarrolló e implementó un nuevo procedimiento de determinación de velocidad y aceleración que extiende el alcance. Este método fue llamado Extended Velocity and Acceleration determination (EVA). Un experimento usando una aeronave ligera volando sobre los Pirineos mostró que tanto el método de Kennedy (modificado) como el método EVA son capaces de responder ante la dinámica de este tipo de vuelos. Finalmente, tanto el método de Kennedy modificado como el método EVA fueron aplicados a una red en la zona ecuatorial de Sur América con líneas de base mayores a 1770 km. En este escenario el método EVA mostró una clara ventaja tanto en los promedios como en las desviaciones estándar para todas las componentes de la velocidad y la aceleración. This Ph.D. Thesis focuses on the development of algorithms and tools for precise GPS-based position, velocity and acceleration determination very far from reference stations in post-process mode. One of the goals of this thesis was to develop a set of state-of-the-art GNSS data processing tools, and make them available for the research community. Therefore, the software development effort was done within the frame of a preexistent open source project called the GPSTk. Therefore, validation of the GPSTk pseudorange-based processing capabilities with a trusted GPS data processing tool was one of the initial task carried out in this work. GNSS data management proved to be an important issue when trying to extend GPSTk capabilities to carrier phasebased data processing algorithms. In order to tackle this problem the GNSS Data Structures (GDS) and their associated processing paradigm were developed. With this approach the GNSS data processing becomes like an assembly line, providing an easy and straightforward way to write clean, simple to read and use software that speeds up development and reduces errors. The extension of GPSTk capabilities to carrier phase-based data processing algorithms was carried out with the help of the GDS, adding important accessory classes necessary for this kind of data processing and providing reference implementations. The performance comparison of these relatively simple GDS-based source code examples with other state-of-the art Precise Point Positioning (PPP) suites demonstrated that their results are among the best. Furthermore, given that the GDS design is based on data abstraction, it allows a very flexible handling of concepts beyond mere data encapsulation, including programmable general solvers, among others. The problem of post-process precise positioning of GPS receivers hundreds of kilometers away from nearest reference station at arbitrary data rates was dealt with, overcoming an important limitation of classical post-processing strategies like PPP. The advantages of GDS data abstraction regarding solvers were used to implement a kinematic PPP-like processing based on a network of stations. This procedure was named Precise Orbits Positioning (POP) because it is independent of precise clock information and it only needs precise orbits to work. The results from this approach were very similar (as expected) to the standard kinematic PPP processing strategy, but yielding a higher positioning rate. Also, the network-based processing of POP seems to provide additional robustness to the results, even for receivers outside the network area. The last part of this thesis focused on implementing, improving and testing algorithms for the precise determination of velocity and acceleration hundreds of kilometers away from nearest reference station. Special emphasis was done on the Kennedy method because of its good performance. A reference implementation of Kennedy method was developed, and several experiments were carried out. Experiments done with very short baselines showed a flaw in the way satellite velocities were computed, introducing biases in the velocity solution. A relatively simple modification was proposed, and it reduced the RMS of 5-min average velocity 3D errors by a factor of over 35. Then, borrowing ideas from Kennedy method and the POP method, a new velocity and acceleration determination procedure named EVA was developed and implemented that greatly extends the effective range. An experiment using a light aircraft flying over the Pyrenees showed that both the modified-Kennedy and EVA methods were able to cope with the dynamics of this type of flight. Finally, both modified-Kennedy and EVA method were applied to a challenging scenario in equatorial South America, with baselines over 1770 km, where EVA method showed a clear advantage in both averages and standard deviations for all components of velocity and acceleration. Lloc i

APA, Harvard, Vancouver, ISO, and other styles

30

Hoyle, B. S. "Position vector sensing from airborne vehicles using a correlation-based method." Thesis, University of Huddersfield, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372382.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Hansson, Anders. "Detection of tool wear in drilling based on axis position signals." Thesis, Högskolan Väst, Avdelningen för maskinteknik och naturvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-10335.

Full text

Abstract:

Cutting operations are important and commonly used operations in the field of manufacturing. Automated machining is today commonly used in CNC-machines. One common drawback with automated machining is that the tool condition is challenging to predict which leads to a conservative tool replacement times. This leads to a low utilisation of the tool economical lifetime and an unnecessary high number of tool replacements. Methods for indirect continuous monitoring of the tool wear exist but usually require retrofitting of external sensors that can be both costly and also interrupt the machine operation due to the additional wiring. It is therefore of interest to investigate the possibility to use the, often high resolution, sensors already fitted in a CNC-machine to extract valuable data that can indirectly give an estimation of the tool condition. This thesis work has, with attention to the X-, Y- and Z-position sensors, resulted in development of algorithms that show relations between tool wear and data acquired from these sensors. The algorithms operate in the frequency domain to determine changes in the dynamic response over the time of tool degradation.

APA, Harvard, Vancouver, ISO, and other styles

32

Blattes, Roxane. "Bases moléculaires de la variégation d'effet de position chez drosophila melanogaster." Toulouse 3, 2006. http://www.theses.fr/2006TOU30115.

Full text

Abstract:

Les séquences satellites III (SATIII) représentent la majeure partie de l’hétérochromatine du chromosome X de drosophile et jouent un rôle dans la variégation d’effet de position du gène white dans l’inversion white-mottled. Leurs caractéristiques structurales dues à leur richesse en dA•dT sont ciblées par des ligands synthétiques du petit sillon de l’ADN, outils qui ont permis de caractériser la fonction des SATIII dans l’assemblage de l’hétérochromatine. Nous avons mis en évidence un rôle de D1, qui reconnaît spécifiquement les SATIII, mais aussi de la topoïsomérase II, dans l’initiation de l’assemblage de l’hétérochromatine. Nos résultats suggèrent que les SATIII pourraient constituer un réservoir de protéines servant à la régulation de la transcription du locus des gènes ribosomiques (rDNA) adjacent aux SATIII. Enfin, nous avons pu identifier un élément frontière qui contrôle le cloisonnement de l’hétérochromatine et jouerait un rôle dans la régulation de l’expression du rDNA Satellite III sequences (SATIII) represent the bulk of drosophila X chromosome heterochromatin and play a key role in position effect variegation (PEV) of the white gene in the white-mottled strain. Their structural characteristics, based on their biased dA•dT rich nucleotidic composition, make them good targets for artificial DNA minor groove binders. Such new tools allowed us to improve the SATIII sequences’ function in heterochromatic structure formation. Our work allows us to shed light on the functional role of the D1 protein, which specifically binds SAT III sequences, as well as topoisomerase II, in the initiation of the heterochromatin assembly. Our results suggest that SATIII sequences represent a reservoir for proteins regulating ribosomal DNA arrays (rDNA) transcription located next to SATIII sequences. We also show involvement of a boundary element in heterochromatin partitioning, which plays a role in regulation of rDNA expression

APA, Harvard, Vancouver, ISO, and other styles

33

Smithanik, Jeffrey Russell. "Optimal vision-based position estimation of an underwater space simulation robot." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1879.

Full text

Abstract:

Thesis (M.S.) -- University of Maryland, College Park, 2004. Thesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

APA, Harvard, Vancouver, ISO, and other styles

34

Cheng, Andrew. "Assignment of Bare Rights to Litigate: Assessing the Modern Doctrinal Position." Thesis, Sydney Law School, 2014. http://hdl.handle.net/2123/12157.

Full text

Abstract:

It is well settled that an assignment of a bare right to litigate (or bare right of action) is prima facie invalid unless the assignee could establish a ‘genuine commercial interest’ in taking the transfer. Although the ‘genuine commercial interest’ test has frequently been applied in Australian cases, little ink has been spilled on elucidating its precise meaning. This paper begins with a critical examination of the mischief behind judicial opposition to assignments of bare rights of action, then proceeds to investigate the meaning of ‘genuine commercial interest’ with particular attention to two contentious aspects, viz.: the need for the assignee to possess a preexisting interest arising separately from the assignment, and the relevance of profit making by the assignee. This paper argues that judicial inquiry should not focus on the nature of the assignee’s interest but rather on the effect of the assignment with reference to the mischief that maintenance and champerty were intended to redress; accordingly, an assignment should not be struck down merely because the assignee lacks a pre-existing interest or makes a profit from the assignment.

APA, Harvard, Vancouver, ISO, and other styles

35

Zhang, Zhongkai. "Vision-based calibration, position control and force sensing for soft robots." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I001/document.

Full text

Abstract:

La modélisation de robots souples est extrêmement difficile, à cause notamment du nombre théoriquement infini des degrés de liberté. Cette difficulté est accentuée lorsque les robots ont des configurations complexes. Ce problème de modélisation entraîne de nouveaux défis pour la calibration et la conception des commandes des robots, mais également de nouvelles opportunités avec de nouvelles stratégies de détection de force possibles. Cette thèse a pour objectif de proposer des solutions nouvelles et générales utilisant la modélisation et la vision. La thèse présente dans un premier temps un modèle cinématique à temps discret pour les robots souples reposant sur la méthode des éléments finis (FEM) en temps réel. Ensuite, une méthode de calibration basée sur la vision du système de capteur-robot et des actionneurs est étudiée. Deux contrôleurs de position en boucle fermée sont conçus. En outre, pour traiter le problème de la perte d'image, une stratégie de commande commutable est proposée en combinant à la fois le contrôleur à boucle ouverte et le contrôleur à boucle fermée. Deux méthodes (avec et sans marqueur(s)) de détection de force externe pour les robots déformables sont proposées. L'approche est basée sur la fusion de mesures basées sur la vision et le modèle par FEM. En utilisant les deux méthodes, il est possible d'estimer non seulement les intensités, mais également l'emplacement des forces externes. Enfin, nous proposons une application concrète : un robot cathéter dont la flexion à l'extrémité est piloté par des câbles. Le robot est contrôlé par une stratégie de contrôle découplée qui permet de contrôler l’insertion et la flexion indépendamment, tout en se basant sur un modèle FEM The modeling of soft robots which have, theoretically, infinite degrees of freedom, are extremely difficult especially when the robots have complex configurations. This difficulty of modeling leads to new challenges for the calibration and the control design of the robots, but also new opportunities with possible new force sensing strategies. This dissertation aims to provide new and general solutions using modeling and vision. The thesis at first presents a discrete-time kinematic model for soft robots based on the real-time Finite Element (FE) method. Then, a vision-based simultaneous calibration of sensor-robot system and actuators is investigated. Two closed-loop position controllers are designed. Besides, to deal with the problem of image feature loss, a switched control strategy is proposed by combining both the open-loop controller and the closed-loop controller. Using soft robot itself as a force sensor is available due to the deformable feature of soft structures. Two methods (marker-based and marker-free) of external force sensing for soft robots are proposed based on the fusion of vision-based measurements and FE model. Using both methods, not only the intensities but also the locations of the external forces can be estimated.As a specific application, a cable-driven continuum catheter robot through contacts is modeled based on FE method. Then, the robot is controlled by a decoupled control strategy which allows to control insertion and bending independently. Both the control inputs and the contact forces along the entire catheter can be computed by solving a quadratic programming (QP) problem with a linear complementarity constraint (QPCC)

APA, Harvard, Vancouver, ISO, and other styles

36

Bharambe, Sachin Vasant. "Smart Environment Based On Real-Time Human Position Tracking For Remote Presence And Collaboration." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/86661.

Full text

Abstract:

Real-time, virtual and mixed reality systems have diverse uses for real-world data visualization, representation, and remote collaboration in distant learning settings, especially in universities. Design of such systems involves challenges in mapping the real world data and physical world structure accurately to digital form of physical space, also called as virtual models. Researchers have created similar systems using multiple cameras, stereo cameras, accelerometers, and motion detectors. This report presents a platform to detect and track real-time locations of people present in buildings and map their location information into virtual models as avatars using omni-directional cameras installed in the physical space. These models were created as part of the Mirror Worlds project. The project infrastructure is funded by National Science Foundation. This infrastructure enables users to connect virtual and physical aspects of the environment through a coordinate-based data networking system to enable interaction with the rest of the system including environment objects and other users. This is an interdisciplinary project where students from various departments have worked on the development of virtual model of the Moss Art Center and Torgersen Hall in Unity / X3D. Some students from the Department of Computer Science have developed a coordinate-based data networking system. The prototype of a detection and tracking algorithm to extract the location information was developed using background subtraction in MATLAB. The proposed approach was developed using the combination of background subtraction and neural networks along with heuristics based on spatial information about the physical space. The system was scaled to work across multiple buildings, extract the location information of people present in the physical space, and map location information into shared virtual space as an avatar. The concept of remote presence was extended to create a collaborative object manipulation application using Leap Motion controller. Effects of fidelity were evaluated to perform the collaborative object manipulation task in shared virtual space based on user study conducted for this application. Since no annotated people video dataset is publicly available with overhead view from omni-directional cameras, three videos were annotated manually to test the performance of the approach. The current approach almost works at near real-time rates. All three video sequences were evaluated to compute frame based detection accuracy. Precision and recall obtained for the first video sequence of people detection is 93.85% and 95.06% respectively. Master of Science

APA, Harvard, Vancouver, ISO, and other styles

37

Einsiedler, Manfred, Selim Tuncel, and manfred@mat univie ac at. "When does a Polynomial Ideal Contain a Positive Polynomial?" ESI preprints, 2000. ftp://ftp.esi.ac.at/pub/Preprints/esi895.ps.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Evanshen, Pamela. "Brain-based Research and Positive Discipline." Digital Commons @ East Tennessee State University, 2006. https://dc.etsu.edu/etsu-works/4408.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Pointoin, Barry William. "Model-based randoms correction for 3D positron emission tomography." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31046.

Full text

Abstract:

Random coincidences (randoms) are frequently a major source of image degradation and quantitative inaccuracies in positron emission tomography. Randoms occurring in the true coincidence window are commonly corrected for by subtracting the randoms measured in a delayed coincidence window. This requires additional processing demands on the tomograph and increases the noise in the corrected data. A less noisy randoms estimate may be obtained by measuring individual detector singles rates, but few tomographs have this capability. This work describes a new randoms correction method that uses the singles rates from an analytic calculation, rather than measurements. This is a logical and novel extension of the model-based methods presently used for scatter correction. The singles calculation uses a set of sample points randomly generated within the preliminary reconstructed radioactivity image. The contribution of the activity at each point to the singles rate in every detector is calculated using a single photon detection model, producing an estimate o f the singles distribution. This is scaled to the measured global singles rate and used to calculate the randoms distribution which is subtracted from the measured image data. This method was tested for a MicroPET R4 tomograph. Measured and calculated randoms distributions were compared using count profiles and quantitative figures of merit for a set of phantom and animal studies. Reconstructed images, corrected with measured and calculated randoms, were also analysed. The calculation reproduced the measured randoms rates to within ≤ 1.4% for all realistic studies. The calculated randoms distributions showed excellent agreement with the measured, except that the calculated sinograms were smooth. Images corrected with both methods showed no significant differences due to biases. However, in the situations tested, no significant difference in the noise level o f the reconstructed images was detected due to the low randoms fractions of the acquired data. The model-based method of randoms correction uses only the measured image data and the global singles rate to produce smooth and accurate random distributions and therefore has much lower demands on the tomograph than other techniques. It is also expected to contribute to noise reduction in situations involving high randoms fraction. Science, Faculty of Physics and Astronomy, Department of Graduate

APA, Harvard, Vancouver, ISO, and other styles

40

Mousa, Farag. "Secure visible light communication systems based on the position of the user." Thesis, Northumbria University, 2017. http://nrl.northumbria.ac.uk/36262/.

Full text

Abstract:

In the past few decades, there has been a growing demand for bandwidth in wireless communication systems due to an increase in the number of mobile users, computer network applications and high speed internet access and services. Visible light communication (VLC) is a newly emerging technology in optical wireless communication (OWC) systems to provide both illumination and high-speed data communication. In addition, it can also be used for indoor positioning or localization with wide applications that has merited a number of attractive research studies. However, security in wireless communications has become a matter of concern due to the possibility of unauthorised access to transmitted data. This thesis investigates received optical power (ROP) distribution to achieve illumination requirements for both optimal and sub-optimal Lambertian order in single and four cell configurations. Furthermore, it proposes VLC-based indoor positioning by using the received optical power levels from the emitting LEDs. Both scenarios of line-of-sight (LOS) and line-of-sight with non-line-of-sight (LOSNLOS) positioning are considered. The performance of the proposed system is evaluated under both noisy and noiseless channel cases and the impact of different location codes on the positioning error is also investigated. An analytical model of the system with noise and the corresponding numerical evaluation for a range of signal to noise ratios (SNRs) are presented. The results show that an accuracy of 8 cm in average is achievable at an SNR of 15 dB in the LOSNLOS scenario. We also introduce a novel approach for recovering 4×4 MIMO–VLC data with partial channel state information (CSI) knowledge both in noisy and noiseless cases. In addition, the proposed indoor localization system utilizing two visible light emitting diodes for different environments offering less complexity for both LOS and LOSNLOS scenarios is offered. The results of the scheme is compared with existing trilateration techniques and the performance of the proposed system is evaluated with a reported accuracy of less than 20 cm for SNR values of greater than 13 dB. This thesis also proposes a new secure single input single output (SISO) VLC system and investigates the bit error rate (BER) performance with and without encryption in the Media Access Control (MAC) layer and physical layer for both the LOS and LOSNLOS scenarios. For a BER of 10-3, the results show that there is 1 to ~ 3.5 dB power penalties for the secured VLC system for data rates of up to 10 Mbps. The key length impact on the error propagation is also investigated. Finally, this thesis proposes a secure MIMO VLC system that relies on the position of the user by incorporating a new modified version of the Rivest-Shamir-Adleman (RSA) technique for encrypting the transmitted data in the MAC layer. Furthermore, the ability of the proposed system to control the size of the encrypted cell depending on the application environment is demonstrated.

APA, Harvard, Vancouver, ISO, and other styles

41

Wang, Chin-Hao, and 王志浩. "Indoor position robot management system base on RFID." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/78344372346829760115.

Full text

Abstract:

碩士 南台科技大學 資訊工程系 97 Indoor Positioning will become an important part of home life in the future, in order to let the robot provide the human’s life quality, this paper present an indoor positioning robot management system base on RFID; in this system users can monitor the remote monitoring robots through the server-side and help robot achieve the allocated place. This paper focuses on RFID position to help server retrieve the position of the robot. The robot-side of this RFID indoor robot management system consists of RFID system, wireless network, image capture, location and obstacle avoidance. And the functions of server-side monitoring include route planning, indoor positioning information and remote control. This paper using RFID indoor position system to record the area、building、floor、householder and room. Each unit, as a consult node on the door or stair, is according to indoor room for the smallest one. Each unit can set the density of RFID tag by user and user can adjust the density of RFID tag flexibly based on user require to improve system performance. This system using Samsung 2443 embedded system platform and Windows CE5.0 system to develop indoor robot. Server-side can remote control the indoor robot move to specified location , and located of robot can be shown on the server-side by the return data from RFID tag. The RFID tag will also save the path and recode the movement data between the RFID tags as the consult of the movement next time.

APA, Harvard, Vancouver, ISO, and other styles

42

Lo, Shing Ming, and 羅世明. "Modeling of a position system's design knowledge base." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/93480861704253336047.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Barbera, Andrew Lawrence. "Corrected head position." 2008. http://hdl.handle.net/2440/53359.

Full text

Abstract:

Background: Historically, many reference lines and planes of the human skull have been used in an attempt to depict the head in a natural head position (NHP) which is a relaxed/balanced position when looking ahead at their eye level. Head position correction has been attempted in fields such as anatomy, art, anthropology, orthodontics, oral and maxillofacial surgery, plastic surgery, and forensics. In orthodontics, oral and maxillofacial surgery, and plastic surgery, corrected head position (CHP) is particularly important for diagnosis of the normality/protrusion/retrusion of the patient’s facial skeleton. Usually a single plane, such as Frankfurt horizontal, is used to correct head position, but its angulation is variable between individuals, because each individual’s anatomy is unique. It has been found previously that the Neutral Horizontal Axis (NHA), Frankfurt horizontal (FH), Krogman-Walker plane (KW plane), and Palatal plane (P plane) demonstrated near parallelism, and these planes averaged -1 to -2 degrees from the true horizontal (HOR, which is a horizontal plane determined as being perpendicular to the earth’s gravitational force) with subjects in NHP. Methods: Craniofacial planes were measured in an Aboriginal Australian sample and in two contemporary samples obtained from Australian orthodontic practices, and the findings were compared with previous studies. Each sample consisted of 40 individuals (20 males and 20 females) with subjects in NHP. The Aboriginal Australian sample was longitudinal (T1, mean age 10 years; T2, mean age 14 years, and T3, mean age 18 years) enabling NHP to be assessed over approximately 8 years. A soft tissue Ear - nose plane (EN plane) was also investigated. Results: NHP reproducibility over 8 years demonstrated a mean of absolute difference of 2.9 degrees, with a range of differences from -7.9 to 8.2 degrees and a standard deviation of differences equal to 3.6 degrees. The Neutral Horizontal Axis (NHA), Frankfurt horizontal (FH), Krogman-Walker plane (KW plane), and Palatal plane (P plane) demonstrated near parallelism with each other, and averaged between 0 and -3 degrees from HOR. On average, EN plane was horizontal but was variable. Conclusions: NHP is not consistently reproducible at the individual level. For hard tissue images, the combined use of NHA, FH, KW plane, and P plane enables prediction of CHP. Additionally, the rectangular shape of the lower orbit - nasal airway region appears to be useful for correcting head position. In facial soft tissue images, EN plane in combination with other visual factors helps to correct head position. Simple geometry enables this head position correction to be performed from any view of the head where relevant landmarks are seen. http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1346599 Thesis (D.Clin.Dent.) - University of Adelaide, School of Dentistry, 2008

APA, Harvard, Vancouver, ISO, and other styles

44

Li, Yen-Hsun, and 李彥勳. "The Research of Performance Improving on the TOA-based Satellites and Base Stations Hybrid Position Method." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/28999916389098983470.

Full text

Abstract:

碩士 國立屏東教育大學 資訊科學系碩士班 102 In this thesis, a positioning method is proposed to improve the accuracy of the Global Position System(GPS). Due to the lack of visible satellites in some areas, GPS may become more inaccurate, and sometimes even lead to malfunction. Generally, the base stations can participate to increase the positioning accuracy. In some areas, the number of visible satellites is less than four but multiple base stations existed in the area, this thesis propose a method called Hybrid Positioning Improved Method (HPIM) to take this situation into consider to improve the positioning performance. The proposed HPIM adopted the TOA (Time of Arrival) method for distance calculation. The simulation results show that our proposed HPIM method outperformed the GPSone method on the comparison of error range and positioning success rate.

APA, Harvard, Vancouver, ISO, and other styles

45

Huang, Yu-Chang, and 黃禹璋. "The effect of hydroxyl group position of rodlike Schiff base mesogen on the formation of blue phase." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/rh3u46.

Full text

Abstract:

碩士 大同大學 化學工程學系(所) 106 Two kinds of intramolecular hydrogen bonding by hydroxyl group with Schiff base or ester group were successfully incorporated into two types of rod-like Schiff base mesogens with -C=N- or -N=C- linkage. These Schiff base are doped with chiral additives S811 and ISO(6OBA)2 to investigate the effect of hydroxyl group position of rodlike Schiff base mesogen on the formation of blue phase (BP). The results show that the presence of intramolecular hydrogen bonding by hydroxyl group with Schiff base or ester group in Schiff base mesogen of series I (-C=N-) reduced BP formation temperature and narrow BP range when Schiff base mesogen is doped with chiral additives S811 or ISO(6OBA)2. For series III(-N=C-), BP could not be induced in the presence of only intramolecular hydrogen bonding between hydroxyl group and Schiff base in the mesogen of series III when chiral dopant S811 is added. Notably, BP emerges when two types of intramolecular hydrogen bonding by hydroxyl group with Schiff base and ester group both exist in Schiff base mesogen of in series III.

APA, Harvard, Vancouver, ISO, and other styles

46

劉書韜. "A Study on the Assessment of the Most Fit Position Classification for Military Base Officers'' Assignment - Air Force Ground Officer." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/45099058003414800633.

Full text

Abstract:

碩士 義守大學 工業工程與管理學系 92 MND conducted recently “The ROC Armed Forces Refining Program” in order to achieve the target of establishing a “compact but delicate, highly capable” and modernized military force. Under the above and resource decrease conditions, military human resource should be managed and distributed more effectively. The concept of human resource in recruitment for entrepreneur has been transformed from employing in conventional “The Best” way to in “The Most Fit” way. The elementary officer in military is the massive rock of the ROC Armed Force. It will be an extraordinary essential lesson in the administrative issue of Nation Defense if the elementary officer will be appropriately assigned to the suitable position, and how to pursue the maximal military performance for the ROC Armed Force. The primary military job description of the ROC Armed Forces can be classified into three groups, commanding, staffing and being professional in a specialty (education). By using FAHP module analysis, this research study will incorporate all comments come from professors and experts in effect ingredients of competence of member assignment. Based on the above comments, the evaluation value of individual job and objective weight will be calculated accordingly. Combined with Fuzzy Synthesis Assessment and Fuzzy Linear Programming, it will be established a fair, objective and perspective evaluation module to reach the purpose of the most appropriate member assignment. It can be proved the feasibility to carry out via putting case into practice and also provide recruitment department and supervisor a good way to evaluate it before elementary officer will be assigned. The test result demonstrates that there are different weights exist in principles of member assignment of each discipline. The portfolio of member assignment calculated from the module is the best one for the advantage of the whole ROC Armed Forces, not for individual “The best fit” consideration use. The advantage of member assignment way is much more efficient than the one of conventional way to pick up one the best for the ROC Armed Forces.

APA, Harvard, Vancouver, ISO, and other styles

47

Hillard, Bruce F. "Base-line calibrations of the Mini-Ranger III and the role of signal strength in correcting real-time hydrographic position data." Thesis, 1986. http://hdl.handle.net/10945/21693.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Bassoo, Vandana. "A digital up-conversion architecture for future high efficiency wireless base stations." Thesis, 2010. https://vuir.vu.edu.au/16051/.

Full text

Abstract:

Over the past few years, there has been a growing need for wireless communications with higher data rates and ubiquitous coverage, and these must be achieved at reduced cost and with a lower carbon footprint. This evolution in wireless demand places a big burden on transmitter architectures. The need for higher efficiency has stimulated research into the potential replacement of current linear power amplifiers (PAs) by switch mode power amplifiers (SMPAs) at cellular frequencies. The radio frequency (RF) PA currently accounts for a significant part of the cost, and most of the power requirements of a typical wireless base station. This research is focused on the modulation and up-conversion circuits for generating the SMPA drive signals. The switched (‘on’/‘off’) nature of the amplifier drive signal creates an opportunity for an all-digital solution removing traditional analog components such as the digital to analog converters, reconstruction filters, quadrature modulator and local oscillators. Digital signal processing techniques used for signal modulation are extended to digital up-conversion to generate suitable drive signals for the SMPA. In this thesis, a sigma-delta (ΣΔ) based technique is used to embed a complex modulation scheme such as OFDM into a single ‘on’-‘off’ bit stream.

APA, Harvard, Vancouver, ISO, and other styles

49

Pazouki, Maryam. "Stable Bases for Kernel Based Methods." Doctoral thesis, 2012. http://hdl.handle.net/11858/00-1735-0000-0010-D298-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Naiser, Thomas. "Characterization of oligonucleotide microarray hybridization microarray fabrication by light-directed in situ synthesis - development of an automated DNA microarray synthesizer, characterization of single base mismatch discrimination and the position-dependent influence of point defects on oligonucleotide duplex binding affinities /." 2008. http://opus.ub.uni-bayreuth.de/volltexte/2008/461/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Position Base'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles