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Sakib, Kazi Muheymin-Us, e s3091580@rmit edu au. "Energy Balanced Sensor Node Organisation For Maximising Network Lifetime". RMIT University. Computer Science and Information Technology, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080805.135709.
Testo completoAbstract (sommario):
Recent advances in Micro-Electro-Mechanical Systems (MEMS) and low-power short-range radios have enabled rapid development of wireless sensor networks. Future sensor networks are anticipated to include hundreds or thousands of these devices in many applications, such as capturing multimedia content for surveillance, structural health monitoring, tracking of accidental chemical leaks, machine failures, earthquakes and intrusion detection. With the increase of sensor applications, a number of challenging problems related to the network protocol design has emerged - the most important ones relating to energy efficiency and lifetime maximisation. Techniques devised for sensor networks should deal with a large number of sensors distributed in the field. Wireless sensor nodes are deployed with limited energy reserves, so the networks should operate with minimum energy overhead. In fact, the network should take into account not only individual node's energy efficiency but also consider the global picture, because surviving nodes' energy reserves in a failed network are wasted energy. This thesis examines a node organisation technique to deal with the above challenges. The focus is on improving network lifetime via organising the nodes in a distributed and energy efficient manner. The main goal is lowering wasted energy via energy balancing and exploiting node redundancy in case of node failure. In particular, this thesis proposes Energy Balanced Clustering (EBC) method for node self-organisation where network tasks (such as data aggregation and data forwarding) are shifted to high-energy neighbours to reduce the energy consumption of low energy nodes. After showing how to extend network lifetime by energy balanced node organisation, the effect of redundant node deployments on network lifetime is addressed. Redundant nodes consume energy by performing unnecessary tasks so a method called Self-Calculated Redundancy Check (SCRC) is proposed to deactivate redundant nodes. A deactivated redundant node can be used as a replacement for a failed node. The Asynchronous Failed Sensor node Detection (AFSD) proposed in this thesis uses the data packets exchanged between neighbours to identify failed neighbours. To restore coverage for network holes caused by failed nodes, policies are given for re-activating redundant nodes. Detailed analytical analysis and simulation of the proposed methods demonstrate that by taking into account energy balancing, eliminating redundant tasks and replacing failed nodes sensor network lifetime can significantly be improved.
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Туранська, Олена Сергіївна. "Розвиток методів захисту інформації в безпроводових сенсорних мережах". Master's thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/23470.
Testo completoAbstract (sommario):
Робота містить 67 сторінку, 4 ілюстрацій, 1 таблиць. Було використано 23 джерела інформації.
Актуальність. В наш час проблема захисту інформації є дуже важливою і для її вирішення витрачається дуже багато ресурсів. Оскільки, безпроводові сенсорні мережі в наш час стають все популярнішими і знаходять своє застосування в багатьох галузях нашого життя, збільшуються і вимоги до такого типу мереж. Безпроводовий зв'язок і особливості експлуатації таких мереж вимагають особливого підходу до питання захисту безпеки в БСМ. Тому дана тема є актуальною.
Метою даної роботи є дослідити особливості експлуатації безпроводових сенсорних мереж, атаки на мережу та існуючі методи захисту інформації. А також запропонувати новий метод захисту інформації в БСМ.
Для досягнення поставленої мети в роботі вирішуються наступні задачі:
дослідження особливостей експлуатації БСМ;
дослідження показників надійності системи безпеки в БСМ;
визначення найрозповсюдженіших атак на мережі такого типу;
дослідження існуючих методів захисту інформації в БСМ;
розробка математичної моделі запропонованого методу покращення захисту інформації в БСМ.
Об’єкт дослідження – безпроводові сенсорні мережі.
Предмет дослідження – атаки на мережу та методи захисту інформації.
Наукова новизна роботи полягає у створенні покращеного методі захисту інформації в безпроводових сенсорних мережах.
Апробація. Результати, що включені у дану роботу, були оприлюднені на двох міжнародних наукових конференціях:
1. ХI Міжнародна Науково-технічна Конференція "ПРОБЛЕМИ ТЕЛЕКОМУНІКАЦІЙ 2017" 18.04-21.04.2017р. на базі Інституту телекомунікаційних систем та НДІ телекомунікацій НТУУ "КПІ";
2. ХІI Міжнародна Науково-технічна Конференція "ПРОБЛЕМИ ТЕЛЕКОМУНІКАЦІЙ 2018" 16.04-20.04.2018р. на базі Інституту телекомунікаційних систем та НДІ телекомунікацій КПІ ім. Ігоря Сікорського.
Публікації:
1. Туранська О.С., Лисенко О.І. Захист інформації у безпроводових сенсорних мережах // Туранська О.С., Лисенко О.І. - «Проблеми телекомунікації»: одинадцята міжнародна науково-технічна конференція, присвячена Дню науки та Всесвітньому Дню телекомунікацій (ПТ-17) 18-21 квітня 2017 р., К.: с. 420…422;
2. Туранська О.С., Петрова В.М. Керівні принципи та підходи до захисту інформації у безпроводових сенсорних мережах // Туранська О.С., Петрова В.М. - «Проблеми телекомунікації»: дванадцята міжнародна науково-технічна конференція, присвячена Дню науки та Всесвітньому Дню телекомунікацій (ПТ-18) 16-20 квітня 2018 р., К.: с. 383…385.
Ключові слова: безпроводова сенсорна мережа, сенсорний вузол, захист інформації, атака на мережу, математична модель.The work contains 67 pages, 4 illustrations, 1 tables, 23 sources of information were used. Topicality. Nowadays the problem of information security is very important and a lot of resources are spent to solve it. Because wireless sensory networks are becoming more popular in our day and are used in many areas of our lives, requirements for such networks also increase. Wireless communication and the features of the operation of such networks require a special approach to security issues in the WSN. The aim of this work is to explore the features of the operation of wireless sensor networks, attacks on the network and existing methods of information protection. And also to propose a new method of information security in WSN. To achieve this goal, the following tasks were set: study of the features of the operation of the WSN; study of reliability indicators of the security system in the WSN; determining the most common attacks on the network of this type; research of existing methods of information security in WSN; development of a mathematical model of the proposed method for improving the protection of information in WSN. The object of research - wireless sensor networks. The subject of research - attacks on the network and methods of information protection. Scientific novelty of work is to create an improved method for protecting information in wireless sensory networks. Approbation. The results included in this work were presented at two international conferences: 1. XI International Scientific Conference "Problems TELECOMMUNICATIONS 2017" 18.04-21.04.2017r. at the Institute of Telecommunication Systems and Telecommunications Research Institute KPI them. Igor Sikorsky. 2. XII International Scientific Conference "Problems TELECOMMUNICATIONS 2018" 16.04-20.04.2018r. at the Institute of Telecommunication Systems and Telecommunications Research Institute "KPI"; Publications: 1. Turanska OS, Lysenko OI Information Security in Wireless Sensor Networks // Turanska OS, Lysenko OI - "Problems of Telecommunications" eleventh international scientific conference dedicated to the Day of Science and World Day of Telecommunications (PT-17) 18-21 April 2017, K .: with. 420…422; 2. Turanska OS, Petrova VM Guiding principles and approaches to information security in Wireless Sensor Networks// Turanska OS, Petrova VM - "Problems of Telecommunications", the twelfth international scientific conference dedicated to the Day of Science and World Day of Telecommunications (PT-18), 16-20 April 2017, K .: p. 383…385; Key words: wireless sensor networks, sensory node, security of information, attack on the network, mathematical model
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Clark, Geoffrey Stuart Williamson. "Improving the energy efficiency and transmission reliability of battery-powered sensor nodes at the edges of a mains-powered wireless network". Thesis, University of Canterbury. Computer Science and Software Engineering, 2012. http://hdl.handle.net/10092/10033.
Testo completoAbstract (sommario):
A masters thesis focussing on achieving improvements in transmission reliability and energy efficiency for a battery-powered wireless sensor node on the edge of an industrial heterogeneous wireless network that consists predominantly of mains-powered nodes. A router-switching technique is proposed to allow the sensor node to make gains in transmission reliability and energy efficiency by taking advantage of the scenario where multiple wireless routers are in range and switching between them, instead of only being able to transmit to one router.
The research involves simulation of a number of network scenarios where the router-switching technique is enabled and disabled, to measure the advantage gained for the sensor in terms of its functional lifetime. The simulation is based on an abstract model that focusses on the edge of the mains-powered area of the network, where the battery-powered sensor is located. The simulation results show that for many cases, router-switching provides a higher level of transmission reliability and lower levels of energy consumption
than the scenario where router-switching is disabled, as well as improvements in data loss rates.
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Vera, Carrasco Luciano. "Sensory quality control of alcoholic beverages using fast chemical sensors". Doctoral thesis, Universitat Rovira i Virgili, 2010. http://hdl.handle.net/10803/9061.
Testo completoAbstract (sommario):
Control de calidad sensorial de bebidas alcohólicas utilizando rápidos sensores químicosEn la presente tesis Doctoral, han sido aplicados dos sensores artificiales para el análisis de
bebidas alcohólicas: la nariz electrónica basada en la espectrometría de masas (MS) y la lengua
electrónica basada en la espectroscopía infrarroja con transformada de Fourier (FTIR). El
propósito fue desarrollar nuevas estrategias para analizar la autenticidad de estos productos,
desde un punto de vista sensorial, por medio de técnicas las espectrales antes mencionadas.
Adicionalmente, ha sido utilizado un espectrofotómetro UV-visible como ojo electrónico. El
trabajo presentado pretende ser un avance significativo hacia el desarrollo de un catador
electrónico mediante la fusión de los tres sensores químicos: nariz electrónica, lengua
electrónica y ojo electrónico.
Sensory quality control of alcoholic beverages using fast chemical sensors
In the present Doctoral Thesis, two chemical artificial sensors are applied to the analysis of
alcoholic beverages: the Mass Spectrometry (MS)-based electronic-noses and Fourier
transform infrared (FTIR)-based electronic-tongue. The aim was developing new strategies to
test the authenticity of these products, from a sensory point of view, by means of the spectral
techniques above mentioned. Additionally, has been used an UV-visible spectrophotometer as
electronic eye. The work presented wants to be a significant advance towards the development
of an electronic taster through the fusion of three chemical sensors: electronic nose, electronic
tongue and electronic eye.
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Simkhada, Shailendra, Christopher Lee, David Venderwerf, Miranda Tyree e Tyler Lacey. "Wireless Sensor Network". International Foundation for Telemetering, 2011. http://hdl.handle.net/10150/595644.
Testo completoAbstract (sommario):
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, NevadaThe scope of this document is the description of design and implementation of the wireless sensor network realized as a part of our Senior Design Capstone Project. The various components and sub-systems that comprise the final product are discussed, followed by the implementation procedures and results.
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Cochran, Travis. "Ultra Low Power Wake-up Receiver with Unique Node Addressing for Wireless Sensor Nodes". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76909.
Testo completoAbstract (sommario):
Power consumption and battery life are of critical importance for medical implant devices. For this reason, devices for Wireless Body Area Network (WBAN) applications must consume very little power. To save power, it is desirable to turn off or put to sleep a device when not in use. However, a transceiver, which is the most power hungry block of a wireless sensor node, needs to listen for the incoming signal continuously. An alternative scheme, is to listen for the incoming signal at a predetermined internal, which saves power at the cost of increased latency. Another and more sophisticated scheme is to provide a wake-up receiver, which listens for the incoming signal continuously, and upon detection of an incoming signal, it wakes the primary transceiver up. A wake-up receiver is typically simple and dissipates little power to make the scheme useful.
This thesis proposes a low-power wake-up receiver, which listens for a wake-up signal, identifies the target node, and wakes up the primary receiver only when that specific node is called upon. When a wake up signal is transmitted to all of the nodes on a network, our wake-up receiver allows all the nodes on a network except the targeted node to remain asleep to save power. Several wake-up receiver topologies have been proposed. This work uses a passive Cockcroft-Walton multiplier circuit as an RF envelope detector followed by a simple detector circuit. A novel serial code detector is then used to decode the pulse width modulated input signal to wake-up the designated node. A passive RF front end and simple decoding circuit reduce power consumption substantially at the cost of low sensitivity. The sensitivity of the wake-up receiver can be improved though the addition of an RF amplifier, but at the cost of increased power consumption.Master of Science
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Lwanga, Evans Leonidace. "Feasibility-Study and Developing of a LoRaWAN® IoT Sensor Node". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Cerca il testo completoAbstract (sommario):
The increasing implementation of IoT technologies guarantees a growing number of connected
devices. These devices range in features depending on their respective applications. Because
of the growing interest and rapid technological advancement of sensor technology, the designing, and deployment of wireless sensor networks has also seen a substantial expansion.
This thesis focuses on developing a sensor-node for a LoRaWAN network, which is one
of the dominant low-power wide-area network technologies. It does so by taking into account
an existing end-device and based on its design and essential performing features, a new design
is proposed and implemented. It comprehensively discusses power consumption, size,
hardware and firmware development and on how all the mentioned contribute to the overall
significance of the end-device. Ultimately, the proposed design is tested by establishing a
complete LoRaWAN network to observe and evaluate the performance upon actual
deployment.
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Elliott, Joanne Margaret. "Conducting polymer odour sensors". Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242764.
Testo completo
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Al-Riyami, Ahmed. "Towards an adaptive solution to data privacy protection in hierarchical wireless sensor networks". Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/towards-an-adaptive-solution-to-data-privacy-protection-in-hierarchical-wireless-sensor-networks(a096db2a-251c-4e9e-a4ff-8bfe4c6f1bf4).html.
Testo completoAbstract (sommario):
Hierarchical Wireless Sensor networks (WSNs) are becoming attractive to many applications due to their energy efficiency and scalability. However, if such networks are deployed in a privacy sensitive application context such as home utility consumption, protecting data privacy becomes an essential requirement. Our threat analysis in such networks has revealed that PPDA (Privacy Preserving Data Aggregation), NIDA (Node ID Anonymity) and ENCD (Early Node Compromise Detection) are three essential properties for protecting data privacy. The scope of this thesis is on protecting data privacy in hierarchical WSNs byaddressing issues in relation to two of the three properties identified, i.e., NIDA and ENCD, effectively and efficiently. The effectiveness property is achieved by considering NIDA and ENCD in an integrated manner, and the efficiency property is achieved by using an adaptive approach to security provisioning. To this end, the thesis has made the following four novel contributions. Firstly, this thesis presents a comprehensive analysis of the threats to data privacy and literature review of the countermeasures proposed to address these threats. The analysis and literature review have led to the identification of two main areas for improvements: (1) to reduce the resources consumed as the result of protecting data privacy, and (2) to address the compatibility issue between NIDA and ENCD.Secondly, a novel Adaptive Pseudonym Length Estimation (AdaptPLE) method has been proposed. The method allows the determination of a minimum acceptable length of the pseudonyms used in NIDA based on a given set of security and application related requirements and constraints. In this way, we can balance the trade-off between an ID anonymity protection level and the costs (i.e., transmission and energy) incurred in achieving the protection level. To demonstrate its effectiveness, we have evaluated the method by applying it to two existing NIDA schemes, the Efficient Anonymous Communication (EAC) scheme and theCryptographic Anonymous Scheme (CAS).Thirdly, a novel Adaptive Early Node Compromise Detection (AdaptENCD) scheme for cluster-based WSNs has been proposed. This scheme allows early detections of compromised nodes more effectively and efficiently than existing proposals. This is achieved by adjusting, at run-time, the transmission rate of heartbeat messages, used to detect nodes' aliveness, in response to the average message loss ratio in a cluster. This adaptive approach allows us to significantly reduce detection errors while keeping the number of transmitted heartbeat messages as low as possible, thus reducing transmission costs. Fourthly, a novel Node ID Anonymity Preserving Scheme (ID-APS) for clusterbased WSNs has been proposed. ID-APS protects nodes ID anonymity while, at the same time, also allowing the global identification of nodes. This later property supports the identification and removal of compromised nodes in the network, which is a significant improvement over the state-of-the-art solution, the CAS scheme. ID-APS supports both NIDA and ENCD by making a hybrid use of dynamic and global identification pseudonyms. More importantly, ID-APS achieves these properties with less overhead costs than CAS. All proposed solutions have been analysed and evaluated comprehensively to prove their effectiveness and efficiency.
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Resul, Hulya. "Node replication detection in sensor networks". College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3253.
Testo completoAbstract (sommario):
Thesis (M.S.) -- University of Maryland, College Park, 2005.Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Olsson, Joel, e Junior Asante. "Using Node-Red to Connect Patient, Staff and Medical Equipment". Thesis, Linköpings universitet, Institutionen för systemteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129781.
Testo completoAbstract (sommario):
The emergency departments in Region Östergötland use pen and paper to a large extent when recording emergency care procedures and measurements. During treatment the patient should be the main focus. Because of this, recording of measurements done could be delayed or in worst case forgotten during stressful situations. The proposal of this project is the development of a prototype that tries to make the administrative work a passive procedure rather than an active one. The system developed uses a Raspberry Pi, along with Node-Red, which connects predefined patient data and medical records, with the clinical staff tending the patient. All these connections are initiated by mainly using RFID technology. The conclusion made with the developed system is that it should unload the staff with the recording of data and that it helps make a data logging a more passive work than today’s used methods. Along with a process that is easier to operate, the time spent on administrative work could be reduced with the proposed system.
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Thomas, Richie J. "EXPERIMENTAL EVALUATION OF EMULI: A TOOL FOR SENSOR ABSTRACTION IN WIRELESS SENSOR NETWORKS". Kent State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=kent1194572149.
Testo completo
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Shenkutie, Daniel Kifetew, e Prashanth Kumar Patil Shinde. "Residual Energy Monitoring in WirelessSensor Networks". Thesis, Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-16432.
Testo completoAbstract (sommario):
Since wireless sensor networks are energy constrained, introducing a method that facilitates the efficient use of the available energy in each node is a fundamental design issue. In this work, a mechanism to monitor the residual energy of sensor networks is proposed. The information about the residual energy of each sensor node in the network is saved in a special node called monitoring node. This information can be used as input to other applications to prolong the network lifetime. Each sensor node in the network uses the proposed prediction-based model to forecast its energy consumption rate. The model's performance is measured based on the number of energy packets sent to the monitoring node for various thresholds (prediction errors). The simulation results showed that reducing the threshold will produce more accurate projection of the residual energy of each node in the monitoring node. However, as the threshold is further decreased the number of energy packets sent to the monitoring node grows significantly. This incurs higher energy map construction cost on the network in terms of energy and bandwidth. The simulation results also showed the tradeoff between increasing the accuracy of the prediction model and reducing the cost of energy map construction.
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Sambhara, Chaitanya. "P-Percent Coverage in Wireless Sensor Networks". Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/cs_theses/56.
Testo completoAbstract (sommario):
Coverage in a Wireless Sensor Network reflects how well a sensor network monitors an area. Many times it is impossible to provide full coverage. The key challenges are to prolong the lifetime and ensure connectivity to provide a stable network. In this thesis we first define p-percent coverage problem in which we require only p% of the whole area to be monitored. We propose two algorithms, Connected P-Percent Coverage Depth First Search (CpPCA-DFS) and Connected P-Percent Connected Dominating Set (CpPCA-CDS). Through simulations we then compare and analyze them for their efficiency and lifetime. Finally in conclusion we prove that CpPCA-CDS provides 5 to 20 percent better active node ratio at low density. At high node density it achieves better distribution of covered area however the lifetime is only 5 to10 percent shorter then CpPCA-DFS. Overall CpPCA-CDS provides up to 30 percent better distribution of covered area.
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Martins, Gilmar Antonio dos Santos. "Identificação de plásticos comerciais por meio de um nariz eletrônico baseado em polímeros condutores". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-31052011-152800/.
Testo completoAbstract (sommario):
O presente trabalho consiste no desenvolvimento de uma nova técnica de identificação de materiais poliméricos por meio do uso de um nariz eletrônico. Narizes eletrônicos têm sido desenvolvidos para detecção automática e classificação de odores e gases. São instrumentos capazes de medir a concentração ou intensidade odorante de modo similar a um olfatômetro, mas sem as limitações inerentes ao uso de painel humano, o que é altamente desejável. O nariz eletrônico é composto por um sistema de sensores, no nosso caso, utilizamos um arranjo de quatro sensores, que foram confeccionados pela deposição de finos filmes de polímeros condutores dopados sobre a superfície de eletrodos interdigitados. Estes sensores foram conectados a condutivímetros acoplados a um computador de uso pessoal (PC) através de um conversor AD. O PC era dotado de softwares de aquisição e tratamento de dados. Amostras dos materiais a serem analisados foram aquecidas a 257°C e o arranjo de sensores foi exposto aos compostos voláteis produzidos durante esse aquecimento. Realizaram-se 30 ensaios formados por períodos de exposição (5 segundos; compostos voláteis) intercalados por períodos de recuperação (45 segundos; ar puro). Os dados obtidos foram tratados estatisticamente por Análises de Componentes Principais (PCA). Esse arranjo de sensores mostrou-se eficiente, sendo capaz de diferenciar nove tipos de materiais poliméricos testados. Apresentou 100% de acerto em 30 ensaios de classificação realizados.This research consists in the development of a new technique capable of the identification of polymeric materials using an electronic nose. Electronic noses have been developed for automatic detection and classification of odors, vapors and gases. They are instruments capable of measuring the concentration or intensity of an odorant similarly to an olfactometer, but without the inherent limitations of the human panel, which is highly desired. The electronic nose is composed by a system of chemoresistive sensors, in this case, an array of four sensors was used, which were made through a deposition of thin films of doped conductive polymers, on the surface of interdigitated electrodes. These sensors were connected to conductivity meters coupled to a personal computer (PC) through AD converters. The PC had acquisition and data processing softwares installed on it. Thirty readings were made or each analyzed polymer consisting of alternated 5 seconds exposure periods and 45 seconds recovery periods. The collected data were statistically processed by Principal Component Analysis (PCA). This electronic nose was efficient, being able to identify nine types of polymeric materials through the analysis of the different volatile compounds released when these materials were heated to the heat of 257ºC. A 100% correct classification score was obtained in the 30 sets of analysis.
16
Abhijith, N. "Semi Conducting Metal Oxide Gas Sensors: Development And Related Instrumentation". Thesis, Indian Institute of Science, 2006. http://hdl.handle.net/2005/281.
Testo completoAbstract (sommario):
A sensor is a technological device or biological organ that detects, or senses, a signal or physical condition and chemical compounds. Technological developments in the recent decades have brought along with it several environmental problems and human safety issues to the fore. In today's world, therefore, sensors, which detect toxic and inflammable chemicals quickly, are necessary. Gas sensors which form a subclass of chemical sensors have found extensive applications in process control industries and environmental monitoring.
The present thesis reports the attempt made in development of Zinc oxide thin film based gas sensors. ZnO is sensitive to many gases of interest like hydrocarbons, hydrogen, volatile organic compounds etc. They exhibit high sensitivity, satisfactory stability and rapid response. In the present work the developed sensors have been tested for their sensitivity for a typical volatile organic compound, acetone. An objective analysis of the various substrates namely borosilicate glass, sintered alumina and hard anodized alumina, has been performed as a part of this work. The substrates were evaluated for their electrical insulation and thermal diffusivity. The microstructure of the gas sensitive film on the above mentioned substrates was studied by SEM technique. The gas sensitive Zinc oxide film is deposited by D.C reactive magnetron sputtering technique with substrate bias arrangement. The characterization of the as-deposited film was performed by XRD, SEM and EDAX techniques to determine the variation of microstructure, crystallite size, orientation and chemical composition with substrate bias voltage. The thesis also describes the development of the gas sensor test setup, which has been used to measure the sensing characteristics of the sensor. It was observed that the ZnO sensors developed with higher bias voltages exhibited improved sensitivity to test gas of interest.
Gas sensors essentially measure the concentration of gas in its vicinity. In order to determine the distribution of gas concentration in a region, it is necessary to network sensors at remote locations to a host. The host acts as a gateway to the end user to determine the distribution of gas concentration in a region. However, wireless gas sensor networks have not found widespread use because of two inherent limitations:
Metal oxide gas sensors suffer from output drift over time; frequent recalibration of a
number of sensors is a laborious task.
The gas sensors have to be maintained at a high temperature to perform the task of gas
sensing. This is power intensive operation and is not well suited for wireless sensor
network.
This thesis reports an exploratory study carried out on the applicability of gas sensors in wireless gas sensor network. A simple prototype sensing node has been developed using discrete electronic components. A methodology to overcome the problem of frequent calibration of the sensing nodes, to tackle the sensor drift with ageing, is presented. Finally, a preliminary attempt to develop a strategy for using gas sensor network to localize the point of gas leak is given.
17
Jung, Changyong. "ON RELAY NODE PLACEMENT PROBLEM FOR SURVIVABLE WIRELESS SENSOR NETWORKS". VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/570.
Testo completoAbstract (sommario):
Wireless sensor networks are widely applied to many fields such as animal habitat monitoring, air traffic control, and health monitoring. One of the current problems with wireless sensor networks is the ability to overcome communication failures due to hardware failure, distributing sensors in an uneven geographic area, or unexpected obstacles between sensors. One common solution to overcome this problem is to place a minimum number of relay nodes among sensors so that the communication among sensors is guaranteed. This is called Relay Node Placement Problem (RNP). This problem has been proved as NP-hard for a simple connected graph. Therefore, many algorithms have been developed based on Steiner graphs. Since RNP for a connected graph is NP-hard, the RNP for a survivable network has been conjectured as NP-hard and the algorithms for a survivable network have also been developed based on Steiner graphs. In this study, we show the new approximation bound for the survivable wireless sensor networks using the Steiner graphs based algorithm. We prove that the approximation bound is guaranteed in an environment where some obstacles are laid, and also propose the newly developed algorithm which places fewer relay nodes than the existing algorithms. Consequently, the main purpose of this study is to find the minimum number of relay nodes in order to meet the survivability requirements of wireless sensor networks.
18
Pasupathy, Karthikeyan. "Anchor Nodes Placement for Effective Passive Localization". Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc33132/.
Testo completoAbstract (sommario):
Wireless sensor networks are composed of sensor nodes, which can monitor an environment and observe events of interest. These networks are applied in various fields including but not limited to environmental, industrial and habitat monitoring. In many applications, the exact location of the sensor nodes is unknown after deployment. Localization is a process used to find sensor node's positional coordinates, which is vital information. The localization is generally assisted by anchor nodes that are also sensor nodes but with known locations. Anchor nodes generally are expensive and need to be optimally placed for effective localization. Passive localization is one of the localization techniques where the sensor nodes silently listen to the global events like thunder sounds, seismic waves, lighting, etc. According to previous studies, the ideal location to place anchor nodes was on the perimeter of the sensor network. This may not be the case in passive localization, since the function of anchor nodes here is different than the anchor nodes used in other localization systems. I do extensive studies on positioning anchor nodes for effective localization. Several simulations are run in dense and sparse networks for proper positioning of anchor nodes. I show that, for effective passive localization, the optimal placement of the anchor nodes is at the center of the network in such a way that no three anchor nodes share linearity. The more the non-linearity, the better the localization. The localization for our network design proves better when I place anchor nodes at right angles.
19
Sims, LT Todd E. "Wireless Sensor Node Data Gathering and Location Mapping". Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/6869.
Testo completoAbstract (sommario):
With advances in wireless communications and miniaturization of mobile sensors, Wireless Sensor Nodes are increasingly being deployed in Ad Hoc fashions. Efficiently gathering data from the networks now becomes a larger problem. Collecting sensor data from a group of nodes deployed in an unknown arrangement in the shortest amount of time requires the collector to utilize a methodology that minimizes collection overlap. Inexpensive commercial off-the-shelf wireless routers and mobile platforms that can be utilized to fly over a field of wireless nodes and create a link connecting to and retrieving the maximum amount of data, are examined in this thesis. The problems are two-fold first, the necessary task of locating the wireless devices in a given area, querying these devices to collect raw data for positioning, and second, the task of then creating a static map of derived locations. In order to enumerate device locations, the relationship of signal strength measurements and round trip signal times between wireless nodes and the wireless access router were investigated in this thesis. The results of this research support the conclusion that an inexpensive collection system can be readily configured for the task of automated client surveying and distance approximation.
20
Chen, Xiangqian. "Defense Against Node Compromise in Sensor Network Security". FIU Digital Commons, 2007. http://digitalcommons.fiu.edu/etd/7.
Testo completoAbstract (sommario):
Recent advances in electronic and computer technologies lead to wide-spread deployment of wireless sensor networks (WSNs). WSNs have wide range applications, including military sensing and tracking, environment monitoring, smart environments, etc. Many WSNs have mission-critical tasks, such as military applications. Thus, the security issues in WSNs are kept in the foreground among research areas. Compared with other wireless networks, such as ad hoc, and cellular networks, security in WSNs is more complicated due to the constrained capabilities of sensor nodes and the properties of the deployment, such as large scale, hostile environment, etc. Security issues mainly come from attacks. In general, the attacks in WSNs can be classified as external attacks and internal attacks. In an external attack, the attacking node is not an authorized participant of the sensor network. Cryptography and other security methods can prevent some of external attacks. However, node compromise, the major and unique problem that leads to internal attacks, will eliminate all the efforts to prevent attacks. Knowing the probability of node compromise will help systems to detect and defend against it. Although there are some approaches that can be used to detect and defend against node compromise, few of them have the ability to estimate the probability of node compromise. Hence, we develop basic uniform, basic gradient, intelligent uniform and intelligent gradient models for node compromise distribution in order to adapt to different application environments by using probability theory. These models allow systems to estimate the probability of node compromise. Applying these models in system security designs can improve system security and decrease the overheads nearly in every security area. Moreover, based on these models, we design a novel secure routing algorithm to defend against the routing security issue that comes from the nodes that have already been compromised but have not been detected by the node compromise detecting mechanism. The routing paths in our algorithm detour those nodes which have already been detected as compromised nodes or have larger probabilities of being compromised. Simulation results show that our algorithm is effective to protect routing paths from node compromise whether detected or not.
21
Fernandes, Ricardo Dias. "Design of a battery-free wireless sensor node". Master's thesis, Universidade de Aveiro, 2010. http://hdl.handle.net/10773/5616.
Testo completoAbstract (sommario):
Mestrado em Engenharia Electrónica e TelecomunicaçõesRedes de sensores sem fios são hoje em dia utilizadas numa grande variedade de aplicações, o que justifica o facto de que os sensores que as constituem sejam igualmente diversificados. Ainda assim, quase todos eles dependem de baterias, as quais ficam sem carga normalmente muito antes do fim de vida dos restantes componentes. Para além disso, o tamanho da baterias é neste momento um impeditivo à redução do tamanho dos sensores. Uma forma de contornar estes problemas consiste em retirar as baterias dos dispositivos e em alternativa captar a energia das ondas electromagnéticas radiadas por uma fonte colocada próxima destes. Neste documento descrevem-se em detalhe um sensor sem fios projectado para captar energia de ondas rádio a 866.6MHz e a respectiva antena. Além de ser passivo, o sistema proposto é também programável, uma vez que o sensor integra um microcontrolador de uso geral, e inclui um conector de 50 e uma interface para depuração e expansão, composta por um total de 26 pinos. Em termos de performance prática, o sistema proposto á capaz de executar tarefas relacionadas com comunicação e processamento atá um máximo de 4.1 metros de distância de uma antena transmissora a operar dentro das limitações impostas pelas entidades reguladoras locais, no que diz respeito a potência.
Wireless sensor networks are currently of primary importance in a multitude of applications, and therefore, it comes as no surprise that there are many types of sensor nodes as well. Yet, almost all of them operate on batteries that normally deplete long before the predicted life span of basically all the other hardware components. Not only that, the large size of the batteries is indeed actually preventing sensor nodes from becoming smaller. One way of overcoming the drawbacks related to batteries is to remove them and harvest all the necessary energy from electromagnetic waves being radiated by a nearby source. In this document, a wireless sensor node designed to harvest energy from radio waves at 866.6MHz and its antenna are proposed and described in detail. In addition to being passive, the proposed system is also programmable, given that the sensor node includes a general-purpose microcontroller, and features a 50 port, and an interface for debugging and expansion, comprised of a total of 26 pins. Lastly, with regards to practical performance, the proposed system is able to carry out communication and processing tasks at up to a distance of 4.1 meters away from a transmitter antenna radiating within the limits imposed by local regulatory entities, with respect to power.
22
Бугрим, І. В., О. О. Винокуров e П. В. Галкін. "Approaches to Designing a Wireless Sensor Network Node". Thesis, NURE, MC&FPGA, 2019. https://mcfpga.nure.ua/conf/2019-mcfpga/10-35598-mcfpga-2019-007.
Testo completoAbstract (sommario):
The object of the research is the hardware component for building a test platform for wireless sensor networks. The aim of the work is to develop a software and hardware test platform for wireless sensor networks. As a result of the analysis, the node structures, wireless sensor network modules, CC2530 peripherals were analyzed. A module based on the CC2530 PA was chosen as the hardware. Given to optimize the structure of the node for as one of approach to designing a wireless sensor network node. Also given report about difference in approach to designing nodes and uses areas.
23
Besnard, Isabelle. "Improvement of conducting polymer gas sensors". Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341716.
Testo completo
24
Bacchiani, Claudio. "Power consumption analysis for self-diagnosis of Wireless Sensor Nodes". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/4010/.
Testo completoAbstract (sommario):
Wireless sensor networks can transform our buildings in smart environments, improving comfort, energy efficiency and safety. Today however, wireless sensor networks are not considered reliable enough for being deployed on large scale.
In this thesis, we study the main failure causes for wireless sensor networks, the existing solutions to improve reliability and investigate the possibility to implement self-diagnosis through power consumption measurements on the sensor nodes. Especially, we focus our interest on faults that generate in-range errors: those are wrong readings but belong to the range of the sensor and can therefore be missed by external observers.
Using a wireless sensor network deployed in the R\&D building of NXP at the High Tech Campus of Eindhoven, we performed a power consumption characterization of the Wireless Autonomous Sensor (WAS), and studied through some experiments the effect that faults have in the power consumption of the sensor.
25
Rimer, Suvendi Chinnappen. "Energy efficient communication models in wireless sensor and actor networks". Thesis, University of Pretoria, 2012. http://hdl.handle.net/2263/23253.
Testo completoAbstract (sommario):
Sensor nodes in a wireless sensor network (WSN) have a small, non-rechargeable power supply. Each message transmission or reception depletes a sensor node’s energy. Many WSN applications are ad-hoc deployments where a sensor node is only aware of its immediate neighbours. The lack of a predefined route path and the need to restrict the amount of communication that occurs within the application area impose constraints on WSNs not prevalent in other types of networks. An area of active research has been how to notify the central sink (or monitoring hub) about an event in real-time by utilising the minimum number of messages to route a message from a source node to the destination sink node. In this thesis, strategies to limit communication within a WSN application area, while ensuring that events are reported on and responded to in real-time, is presented. A solution based on modelling a WSN as a small world network and then transmitting an initialisation message (IM) on network start-up to create multiple route paths from any sensor node to one or more sinks is proposed. The reason for modelling a WSN as a small world network is to reduce the number of nodes required to re-transmit a message from a source sensor node to a sink. The purpose of sending an IM at network start-up is to ensure that communication within the WSN is minimised. When routing a message to a static sink, the nodes closest to the static sink receive a disproportionate number of messages, resulting in their energy being consumed earlier. The use of mobile sinks has been proposed but to our knowledge no studies have been undertaken on the paths these mobile sinks should follow. An algorithm to determine the optimum path for mobile sinks to follow in a WSN application area is described. The purpose of an optimum path is to allow more equitable usage of all nodes to transfer an event message to a mobile sink. The idea of using multiple static sinks placed at specific points in the small world model is broadened to include using multiple mobile sinks called actors to move within a WSN application area and respond to an event in real-time. Current coordination solutions to determine which actor(s) must respond to the event result in excessive message communication and limit the real-time response to an event. An info gap decision theory (IGDT) model to coordinate which actor or set of actors should respond to the event is described. A comparison of the small world routing (SWR) model against routing using flooding and gossiping shows that the SWR model significantly reduces the number of messages transmitted within the network. An analysis of the number of IMs transmitted and received at individual node level shows that prudent selection of the hop count (number of additional nodes required to route a message to sink) to a sink node will result in a reduced number of messages transmitted and received per node within the network. The use of the IGDT model results in a robust decision on the actor(s) chosen to respond to an event even when uncertainty about the location and available energy of other actor(s) exists.Thesis (PhD(Eng))--University of Pretoria, 2012.
Electrical, Electronic and Computer Engineering
unrestricted
26
Prangova, Mimi. "Visualization of Sensory Perception Descriptions". Thesis, Linnéuniversitetet, Institutionen för datavetenskap, fysik och matematik, DFM, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-9130.
Testo completoAbstract (sommario):
Visualization of Sensory Perception Descriptors is a topic in the field of Information Visualization. It is concentrated on the research and development of methods for analyses of data related with human modalities description. One possibility for investigating sensory perception descriptors is analyzing a great number of wine tasting notes. This thesis is concerned with the visualization of wine tasting notes in order to aid linguistic analyses. It strives to find proper visualizations that will give a better insight into the language used in wine tasting notes. Two main processes are described in the following report. First it sets out the process of researching of different methods of information visualization that led to the final approach for representing the data. A number of concepts for text analyses are discussed and the most useful of them are developed further. Several approaches for text visualization and statistical information are combined to build a system for tasting notes analyses. The second part of the report describes the process of developing a prototype that implements the represented approaches and gives an opportunity for real testing and conclusions.
27
Ottallah, Noor. "Implementation of Secure Key Management Techniques in Wireless Sensor Networks". ScholarWorks@UNO, 2008. http://scholarworks.uno.edu/td/703.
Testo completoAbstract (sommario):
Creating a secure wireless sensor network involves authenticating and encrypting messages that are sent throughout the network. The communicating nodes must agree on secret keys in order to be able to encrypt packets. Sensor networks do not have many resources and so, achieving such key agreements is a difficult matter. Many key agreement schemes like Diffie-Hellman and public-key based schemes are not suitable for wireless sensor networks. Pre-distribution of secret keys for all pairs of nodes is not viable due to the large amount of memory used when the network size is large. We propose a novel key management system that works with the random key pre-distribution scheme where deployment knowledge is unknown. We show that our system saves users from spending substantial resources when deploying networks. We also test the new system’s memory usage, and security issues. The system and its performance evaluation are presented in this thesis.
28
Pottinger, Mark Gerard. "Localisation of underwater sensor nodes in confined spaces". Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/localisation-of-underwater-sensor-nodes-in-confined-spaces(50095cdd-28a2-4a63-b683-80cbff55b6b1).html.
Testo completoAbstract (sommario):
The aim of the project is to explore 3D localisation of a sensor “pill”, contained in an enclosed vessel, using multiple acoustic transducers mounted on the pill‟s surface. The thesis suggests strategies for placement, excitation and synchronisation of the transmitters on the pill and receivers on the vessel wall to deliver 3D localisation. Motivation for the project has emerged from the desire to develop wireless sensor networks to monitor the internals of industrial processes. A major challenge relates to the ability to accurately determine the location of the pill within the vessel, in the presence of multipath reflections. The main challenges relate to the determination of suitable transmission methodologies and synchronisation strategies to allow accurate localisation. The pill has to be a finite size in order to contain the required sensor hardware and transducers must be mounted on the surface of the pill such that signals are able to propagate directly to receivers on the vessel wall. This presents challenges in optimising the transmitter and receiver layout to maximise signal strength and also to determine how the separation of multiple transmitters on the pill impacts localisation accuracy. Time-Difference-of-Arrival (TDOA) has been investigated as a localisation technique, with simulations revealing that the separation of transmitters on the pill influences the accuracy. By modifying the standard TDOA equations with offset knowledge it has been demonstrated, in simulation, that this error can be reduced and by uniquely coding transmitters it is possible to resolve rotation of the pill in the vessel allowing further reduction in localisation error. Simulations have investigated how the location of receivers on the vessel wall influences the localisation error when the TDOA values are compromised by noise. It has been demonstrated that by mounting receivers at the extremities of the vessel the localisation error of the pill can be reduced. Work has also been undertaken to characterise both the vessel reflection properties and also the transmitter beam profile to allow a suitable transmitter layout on the pill to be determined. Simulations, supported by experimental results, have shown that a curved vessel surface can focus the reflected signals and therefore compromise peak detection signal methodologies. As a result amplitude thresholding is suggested for detecting received signals. The research is substantiated with a simple demonstrator that suggests, for both Time-of-Flight (TOF) and Time-Difference-of-Arrival techniques, that the location of the pill can be determined with an accuracy of ± 5 cm throughout a 250 litre vessel. This is the first time that underwater localisation in a confined space using multiple transmitters on the surface of a sensor “pill” has been reported.
29
Belletti, Francesco. "Soluzioni wireless low power per nodi sensori miniaturizzati". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15659/.
Testo completoAbstract (sommario):
Uno degli aspetti potenzialmente più rivoluzionari nel settore sanitario è l'applicazione delle Wireless Sensor Networks (WSN), ovvero un insieme di dispositivi elettronici autonomi in grado di prelevare dati dall'ambiente circostante e di interagire tra loro tramite protocolli di comunicazione wireless.
Un'introduzione a queste reti è presente nella prima parte dell'elaborato, con particolare attenzione ai possibili impieghi in ambito medico.
In seguito, vengono presi come riferimento dell'analisi i sensori impiantabili direttamente su protesi, per monitorare lo spostamento oppure l'effettiva realizzazione di un impianto e, come oggetto di studio, la trasmissione dei dati dal sensore interno al corpo verso l'esterno, finalizzato alla riduzione dei cablaggi rivolti al paziente nella misura di determinati segnali fisiologici.
Obiettivo di questo elaborato è lo studio di due protocolli di comunicazione wireless che utilizzano onde radio come mezzo trasmissivo: Near Field Communication e Bluetooth Low Energy.
Infine, vengono analizzate le prestazioni, prendendo in esame principalmente i consumi energetici e le dimensioni delle possibili soluzioni offerte dal mercato.
30
Sendra, Compte Sandra. "Deployment of Efficient Wireless Sensor Nodes for Monitoring in Rural, Indoor and Underwater Environments". Doctoral thesis, Editorial Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/32279.
Testo completoAbstract (sommario):
Existen muchos trabajos relacionados con el diseño y desarrollo de nodos sensores, donde se presentan gran variedad de aplicaciones. Las redes de sensores inalámbricos pueden facilitarnos y mejorar algunos aspectos de nuestra vida diaria. Es fácil, pensar que si este tipo de dispositivo es tan beneficioso para nosotros y para el entorno donde vivimos, su precio debería ser relativamente barato. Pero podemos comprobar que esto no es así. ¿Por qué estos dispositivos son tan caros? ¿Sería posible desarrollar dispositivos con las mismas capacidades y precios más económicos? ¿Cómo puedo fabricar mis nodos sensores de bajo coste?
Esta tesis responde a estas preguntas y muestra algunas de las muchas aplicaciones que los nodos sensores pueden tener. En esta tesis hemos propuesto (e implementado en algunos casos) el desarrollo de nodos sensores para la monitorización del medio, a partir de dispositivos de bajo coste. Para la implementación de un nodo sensor, y en definitiva la red que une a todos estos nodos, es importante conocer el medio donde trabajarán. A lo largo de este documento se presentan las investigaciones llevadas a cabo para el desarrollo de sensores en tres ámbitos de aplicación.
En el primero de ellos, se desarrollan dispositivos multisenores para la monitorización del medio. La aplicación de las redes de sensores inalámbricas al medio natural, precisa un estudio de cómo se ven afectadas las señales, en función de la distancia, vegetación, humedad del ambiente, etc. Focalizamos nuestros desarrollos en la verificación de incendios en zonas rurales y en el control de plagas en viñedos donde la detección precoz de estos eventos genera elevados ahorros económicos. También proponemos el desarrollo de una red de collares sensores para ganado domestico, que nos ayudará a reducir y prevenir en muchos casos, los ataques de lobos y hurtos de crías. Por último, dentro de este grupo, presentamos una red permite detectar anomalía de los materiales en edificios y red de sensores que nos permite monitorizar las personas mayores o deficientes, que se mueven junto con un grupo, en una excursión o actividad.
El segundo grupo de aplicaciones, hace referencia a la monitorización de espacios en entornos de interior. Para ello hemos analizado el comportamiento de las señales inalámbricas en diferentes escenarios. Los resultados, nos han permitido extraer un nuevo método de diseño de las redes inalámbricas en interiores. Nuestro método, permite definir la mejor ubicación de los dispositivos de red y nodos sensores en interiores con un ahorro en el número de sensores del 15%.
Por último, se presenta el estudio sobre las comunicaciones subacuáticas basadas en las ondas electromagnéticas donde analizamos la dependencia de las comunicaciones subacuáticas en agua dulce en función de la frecuencia, temperatura, tasas de transferencia de datos y modulación.
Relacionado con el medio subacuático, presentamos 2 propuestas. La primera de ellas hace referencia a la implementación de una red de sensores para granjas marinas que nos permite reducir la cantidad de residuos depositados en el lecho marino y reducir el porcentaje de comida desperdiciada. La segunda propuesta es el desarrollo de dos sensores oceanográficos que nos permitirían controlar la cantidad de comida y heces depositadas en el suelo y controlar la turbidez del agua de manera muy simple y económica
Todos estos desarrollos y propuestas, han estado precedidos por un exhaustivo estudio sobre los problemas energéticos que las redes de sensores inalámbricas presentan y las técnicas que pueden emplearse, para prolongar la vida útil de la red y mejorar su estabilidad.There are many works related to the design and development of sensor nodes which present several applications. Wireless sensor networks can facilitate and improve some aspects of our daily lives. It is easy to think that if this type of device is so beneficial to us and to our environment, its price should be relatively cheap. But we can see that this is not true. Why these devices are so expensive? Would it be possible to develop devices with the same capabilities and lower prices? How can I make my low-cost sensor nodes? This dissertation answers these questions and shows some of the many applications that sensor nodes may have. In this dissertation, we propose (and implement in some cases) the development of sensor nodes for environmental monitoring, from low-cost devices. For the implementation of a sensor node and network which joins all these nodes, it is important to know the environment where they will work. Throughout this dissertation, we present the research carried out for the development of sensors in three main application areas. In the first of these areas, we present multisensor devices developed for environmental monitoring. The application of wireless sensor networks to the environment requires a study of how signals are affected depending on the distance, vegetation, ambient humidity, etc. We focus our developments on the fire detection in rural areas and on the control of pests in vineyards where the early detection of these events generates high economic savings. We also propose the development of a sensor network which will help us to reduce and prevent wolves¿ attacks and theft in livestock. Finally, within this group, we present a network to detect material anomalies in building and a sensor network which allows us to monitor the elderly or disabled people who move along with a group on a tour or activity. The second group of applications is related to the monitoring of spaces in indoor environments. For this, we analyze the behavior of wireless signals in different scenarios. These results allowed us to extract a new method for designing wireless networks in indoor environments. Our method allows defining the best location of network devices and sensor nodes indoors saving 15% of the sensors needed. Finally, we present a study on underwater freshwater communications based on electromagnetic waves, where we analyze the dependency of underwater communications as a function of working frequency, temperature, data transfer rates and modulation. Related to underwater environment, we present two proposals. First one refers to the implementation of a sensor network for marine farms which allows us to reduce the amount of waste deposited on the seabed and reduce the percentage of wasted food. The second proposal is the development of two oceanographic sensors which allow us to control the amount of food and feces deposited in seabed and the water turbidity control in a very simple and inexpensive way. All these developments and proposals have been preceded by a comprehensive study on the energy problems in wireless sensor networks. We have also presented several techniques which can be used to prolong the network lifetime and improve its stability.
Sendra Compte, S. (2013). Deployment of Efficient Wireless Sensor Nodes for Monitoring in Rural, Indoor and Underwater Environments [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/32279
Alfresco
31
Famoriyo, Olusola. "THE EVALUATION OF TINYOS WITH WIRELESS SENSOR NODE OPERATING SYSTEMS". Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-886.
Testo completoAbstract (sommario):
Wireless Sensor nodes fall somewhere in between the single application devices that do
not need an operating system, and the more capable, general purpose devices with the
resources to run a traditional embedded operating system. Sensor node operating system
such as TinyOS, Contiki, MantisOS and SOS which is discussed in this paper exhibit
characteristics of both traditional embedded systems and general-purpose operating systems
providing a limited number of common services for application developers linking
software and hardware.
These common services typically include platform support, hardware management of sensors,
radios, and I/O buses and application construction etc. They also provide services
needed by applications which include task coordination, power management, adaptation
to resource constraints, and networking. The evaluation was concentrated on TinyOS
including an analysis on version 1.x and 2.x resource management and flexibility and its
operation with the other wireless sensor node operating systems.
32
Iwendi, Celestine O. "Security techniques and implementation for wireless sensor network nodes". Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=195992.
Testo completo
33
Valente, André Gonçalo Sabino. "DSCL and GSCL in ETSI M2M platform". Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14554.
Testo completoAbstract (sommario):
Mestrado em Engenharia Eletrónica e TelecomunicaçõesMachine to Machine (M2M) is a technology facing huge expansion in the coming years. One can claim that digital technological breakthroughs have changed modern society and the way it interacts with the surroundings. The decreasing prices of sensors/actuators have led to a completely new way of managing industry. The abundance of existing networks, has revolutionized the way a company can check, provide and regulate information about his product. A concept that we must take into account and is very often associated with M2M communications is the Internet of Things, the purpose of this approach is to connect billions of objects and take advantage of their functions as many times as intended. This dissertation will have its focus on developing components for an architecture node M2M. It will focus on certain critical components like the Device Service Capabilities Layer (DSCL), belonging to ETSI M2M architecture according to TS 120 690 standard. These components are traditionally called sensor nodes, in this document technical requirements and limitations are going to be faced aiming a final design.
M2M é uma tecnologia voltada para grande expansão nos próximos anos. Pode-se afirmar que os avanços tecnológicos digitais mudaram a sociedade moderna e a forma como esta interage com o ambiente. Os preços decrescentes de sensores/atuadores levaram a uma forma completamente nova de gestão da indústria. A abundância de redes existentes, revolucionou o modo como uma empresa pode verificar, fornecer e regular as informações sobre o seu produto. Um conceito que temos de levar em conta e é muito frequentemente associado com comunicações M2M é a Internet das coisas, o objetivo dessa abordagem é conectar bilhões de objetos e tirar proveito de suas funções varias vezes. Esta dissertação terá seu foco no desenvolvimento de um nó para uma arquitetura M2M. Esta irá se concentrar em determinados componentes críticos, como o DSCL, pertencente à arquitetura M2M do standard European Telecommunications Standards Institute (ETSI) de acordo com o padrão TS 120 690. Estes equipamentos são tradicionalmente chamados nós, neste documento os requisitos técnicos e as limitações vão ser confrontados com o objetivo de projetar um protótipo final.
34
Zhu, Zhenhuan. "Investigation of wireless sensor nodes with energy awareness for multichannel signal measurement". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/investigation-of-wireless-sensor-nodes-with-energy-awareness-for-multichannel-signal-measurement(36d8020b-a6e3-40e3-900e-5e941024990f).html.
Testo completoAbstract (sommario):
Wireless Sensor Networks (WSNets), consisting of a lot of Wireless Sensor Nodes (WSNs), play an important role in structural health and machine condition monitoring. But the WSNs provided by the current market cannot meet the diversity of application requirements because they have limited functions, unreliable node performance, high node cost, high system redundancy, and short node lifespan. The aim of the research is to design the architecture of a WSN with low power consumption and node cost, which can be dynamically configured according to application requirements for structural health and machine condition monitoring. This research investigates the improvement of node performance and reliability through the new design methodologies and the extension of node lifespan by interfacing energy harvesters and implementing node power management. The main contributions of the research are presented from the following aspects:1. Model development of node architecture for application diversityThe merits of model include: (1) The proposed node architecture can be dynamically configured in terms of application requirements for reducing system redundancy, power consumption and cost; (2) It supports multichannel signal measurement with the synchronous and asynchronous signal sampling modules and three interface circuits; (3)The model parameters can be calculated; (4) As the model is based on discrete electronic components, it can be implemented by using Components-Off-The-Shelf (COTS).2. A novel pipeline design of the built-in ADC inside a microprocessorThe merit of proposed pipeline solution lies in that the sampling time of the built-in ADCs is reduced to one third of the original value, when the ADC operates in sequence sampling mode based on multichannel signal measurement.3. Self-adjusting measurement of sampled signal amplitude This work provides a novel method to avoid the distortion of sampled signals even though the environmental signal changes randomly and over the sampling range of the node ADC. The proposed method can be implemented with four different solutions.4. Interface design to support energy harvesting The proposed interface will allow to: (1) collect the paroxysmal ambient energy as more as possible; (2) store energy to a distribution super-capacitor array; (3) harvest electrical energy at high voltage using piezoelectric materials without any transformer; (4) support the diversity of energy transducers; and (5) perform with high conversion efficiency.5. A new network task scheduling model for node wireless transceiver The model allows to: (1) calculate node power consumption according to network task scheduling; (2) obtain the optimal policy for scheduling network task.6. A new work-flow model for a WSN The model provides an easy way to (1) calculate node power consumption according to the work flow inside a WSN; (2) take fully advantage of the power modes of node electronic components rather than outside factors; (3) improve effectively node design.
35
Imran, Muhammad. "Energy Efficient and Programmable Architecture for Wireless Vision Sensor Node". Doctoral thesis, Mittuniversitetet, Avdelningen för elektronikkonstruktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-20179.
Testo completoAbstract (sommario):
Wireless Vision Sensor Networks (WVSNs) is an emerging field which has attracted a number of potential applications because of smaller per node cost, ease of deployment, scalability and low power stand alone solutions. WVSNs consist of a number of wireless Vision Sensor Nodes (VSNs). VSN has limited resources such as embedded processing platform, power supply, wireless radio and memory. In the presence of these limited resources, a VSN is expected to perform complex vision tasks for a long duration of time without battery replacement/recharging. Currently, reduction of processing and communication energy consumptions have been major challenges for battery operated VSNs. Another challenge is to propose generic solutions for a VSN so as to make these solutions suitable for a number of applications. To meet these challenges, this thesis focuses on energy efficient and programmable VSN architecture for machine vision systems which can classify objects based on binary data. In order to facilitate generic solutions, a taxonomy has been developed together with a complexity model which can be used for systems’ classification and comparison without the need for actual implementation. The proposed VSN architecture is based on tasks partitioning between a VSN and a server as well as tasks partitioning locally on the node between software and hardware platforms. In relation to tasks partitioning, the effect on processing, communication energy consumptions, design complexity and lifetime has been investigated. The investigation shows that the strategy, in which front end tasks up to segmentation, accompanied by a bi-level coding, are implemented on Field Programmable Platform (FPGA) with small sleep power, offers a generalized low complexity and energy efficient VSN architecture. The implementation of data intensive front end tasks on hardware reconfigurable platform reduces processing energy. However, there is a scope for reducing communication energy, related to output data. This thesis also explores data reduction techniques including image coding, region of interest coding and change coding which reduces output data significantly. For proof of concept, VSN architecture together with tasks partitioning, bi-level video coding, duty cycling and low complexity background subtraction technique has been implemented on real hardware and functionality has been verified for four applications including particle detection system, remote meter reading, bird detection and people counting. The results based on measured energy values shows that, depending on the application, the energy consumption can be reduced by a factor of approximately 1.5 up to 376 as compared to currently published VSNs. The lifetime based on measured energy values showed that for a sample period of 5 minutes, VSN can achieve 3.2 years lifetime with a battery of 37.44 kJ energy. In addition to this, proposed VSN offers generic architecture with smaller design complexity on hardware reconfigurable platform and offers easy adaptation for a number of applications as compared to published systems.
36
OVERLY, TIMOTHY G. S. "DEVELOPMENT AND INTEGRATION OF HARDWARE AND SOFTWARE FOR ACTIVE-SENSORS IN STRUCTURAL HEALTH MONITORING". University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1178813386.
Testo completo
37
Blagoi, Gabriela. "Fluorescence resonance energy transfer (FRET) based sensors for bioanalysis". ScholarWorks@UNO, 2004. http://louisdl.louislibraries.org/u?/NOD,146.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of New Orleans, 2004.Title from electronic submission form. "A dissertation ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry."--Dissertation t.p. Vita. Includes bibliographical references.
38
Stanis, Deepak Michael. "Estimation of optimal node degree for ad-hoc sensor networks". Thesis, Wichita State University, 2009. http://hdl.handle.net/10057/2416.
Testo completoAbstract (sommario):
Recent developments in sensor networks have led to a number of routing schemes that
use the limited resources available at sensor nodes more efficiently. Control traffic
analysis plays a major role in ad hoc sensor networks in optimizing the energy used in the
network.
In this research, we present an effective method to estimate the number of nodes
to be deployed in a given area. We analyze the optimal node degree under different levels
of mobility. We consider two parameters, packet delivery ratio and control traffic for the
estimation of optimal node degree. The quantitative and simulation results provide a
detailed analysis of the working of protocols and they can be used to design efficient
routing protocols for ad hoc networks.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering
39
Alaei, Mohammad. "Energy efficient cooperative node management for wireless multimedia sensor networks". Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/129154.
Testo completoAbstract (sommario):
In Wireless Multimedia Sensor Networks (WMSNs) the lifetime of battery operated visual nodes is limited by their energy consumption, which is proportional to the energy required for sensing, processing, and transmitting the data. The energy consumed in multimedia sensor nodes is much more than in the scalar sensors; a multimedia sensor captures images or acoustic signals containing a huge amount of data while in the scalar sensors a scalar value is measured (e.g., temperature). On the other hand, given the large amount of data generated by the visual nodes, both processing and transmitting image data are quite costly in terms of energy in comparison with other types of sensor networks. Accordingly, energy efficiency and prolongation of the network lifetime has become a key challenge in design and implementation of WMSNs. Clustering in sensor networks provides energy conservation, network scalability, topology stability, reducing overhead and also allows data aggregation and cooperation in data sensing and processing. Wireless Multimedia Sensor Networks (WMSNs) are characterized for directional sensing, the Field of View (FoV), in contrast to scalar sensors in which the sensing area usually is uniform and non-directional. Therefore, clustering and the other coverage-based techniques designed for WSNs, do not satisfy WMSNs. In WMSNs, sensor management policies are needed to assure balance between the opposite requirements imposed by the wireless networking and vision processing tasks. While reducing energy consumption by limiting data transmissions is the primary challenge of energy-constrained visual sensor networks, the quality of the image data and application, QoS, improve as the network provides more data. In such an environment, the optimization methods for sensor management developed for wireless sensor networks are hard to apply to multimedia sensor networks. Such sensor management policies usually employ the clustering methods which form clusters based on sensor neighbourhood or radiocoverage. But, as it was mentioned, because of the main difference between directional sensing region of multimedia sensors and the sensing range of scalar sensors, these schemes designed for WSNs, do not have efficiency for WMSNs. Moreover, sensor management strategies of WSNs do not consider the eventdriven nature of multimedia sensor networks, nor do they consider the unpredictability of data traffic caused by a monitoring procedure. This thesis, first, present a novel clustering mechanism based on the overlapping of the FoV of multimedia nodes. The proposed clustering method establishes clusters with grouping nodes that their FoVs overlap at least in a minimum threshold area. Two styles of cluster membership are offered by the mechanism depending on the desired network application; Single Cluster Membership (SCM) and Multi Cluster Membership (MCM). The name of MCM comes from the fact that a node may belong to multiple clusters, if its FoV intersects more than one cluster-head (CH) and satisfies the threshold area while in SCM each node belongs to exactly one cluster. Then, the proposed node management schemes designed for WMSNs are presented; the node selection and scheduling schemes manage the acts of the multimedia sensor nodes in a collaborative manner in clusters with employing the mentioned clustering method. Intra-Cluster Cooperation (ICC) and Intra&Inter-Cluster Cooperation (IICC) use the SCM and MCM clusters respectively. The monitoring period is optimized and the sensing region is divided among clusters and multimedia tasks are performed applying cooperation within and between clusters. The objective is conserving the residual energy of nodes to prolong the network lifetime. Finally, a hybrid architecture for WMSNs in order to energy efficient collaborative surveillance is proposed. The proposed mechanism employs a mixed random deployment of acoustic and visual sensor nodes. Acoustic sensors detect and localize the occurred event/object(s) in a duty-cycled manner by sampling the received signals and then trigger the visual sensor nodes covering the objects to monitor them. Hence, visual sensors are warily scheduled to be awakened just for monitoring the object(s) detected in their domain, otherwise they save their energy. Section B. 4 of Chapter I introduces the contributions of this thesis.
40
Clernon, George. "Exploring the wireless sensor node tradespace within Structural Health Monitoring". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100370.
Testo completoAbstract (sommario):
Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 69-74).
Historically, Structural Health Monitoring (SHM) involved visually or acoustically observing a structure and if damage was detected, remedial action was undertaken to repair or replace it. For example, as early as 6,500 BC, potters were known to listen for audible sounds during the cooling of their ceramics, signifying structural failure. In 1864 the UK parliament legislated for dam monitoring after a dam failure lead to the deaths of 254 people. The Golden Gate and Bay Bridges in San Francisco were monitored by Dean S. Carder in 1937 to determine "the probabilities of damage due to resonance" during an earthquake. Given the technological limitations of the last century, the predominant focus of SHM has been on identifying and understanding the global modal properties of a structure. However, the promise of SHM is the detection of any damage to infrastructure at the earliest possible moment from an array of sensors and actuators. To achieve this goal, not only global but local facets of the structure must be monitored. If this promise is realized, it will be possible to design bridges closer to their tolerances, to extend their operational lives, and to switch servicing to more cost-effective condition based maintenance. Such changes will reduce construction and maintenance costs while still providing the same level of service. This thesis will explore the wireless sensor node tradespace with the specific intent of delving into the areas limiting large scale, high density, localized coverage of structural health monitoring of bridges.
by George Clernon.
S.M. in Engineering and Management
41
Zhou, Dao. "Ultra Low-Power Wireless Sensor Node for Structural Health Monitoring". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31103.
Testo completoAbstract (sommario):
Structural Health Monitoring (SHM) is the technology of monitoring and assessing the condition of aerospace, civil, and mechanical infrastructures using a sensing system integrated into the structure. Among variety of SHM approaches, impedance-based method is efficient for local damage detection. This thesis focuses on system level concerns for impedance-based SHM. Two essential requirements are reached in the thesis: reduction of power consumption of wireless SHM sensor, and compensation of temperature dependency on impedance. The proposed design minimizes power by employing on-board signal processing, and by eliminating power hungry components such as ADC and DAC. The prototype implemented with MSP430 micro controller is verified to be able to handle SHM operation and wireless communication with extremely low-power: 0.15 mW during the inactive mode and 18 mW during the active mode. Each SHM operation takes about 13 seconds to consume 236 mJ. When our ASN-2 operates once in every four hours, it can run for about 2.5 years with two AAA-size batteries. To compensate for temperature change, we proposed an algorithm to select a small subset of baseline profiles for some critical temperatures and to estimate the baseline profile for a given ambient temperature through interpolation. Experimental results show that our method reduces the number of baseline profiles to be stored by 45%, and estimates the baseline profile of a given temperature accurately.Master of Science
42
Tian, Di. "Node activity scheduling schemes in large-scale wireless sensor networks". Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/29266.
Testo completoAbstract (sommario):
In wireless sensor networks that consist of a large number of low-power, short-lived, unreliable sensors, one of the main design challenges is to obtain long system lifetime without sacrificing sensing quality; i.e. sensing coverage in this context. In this thesis, we first propose a node-scheduling scheme, which can reduce system overall energy consumption, therefore increasing system lifetime, by identifying redundant nodes with respect to sensing coverage and then assigning them an off duty operation mode which has lower energy consumption than the normal on-duty mode. Our scheme aims at completely preserving original sensing coverage. Practically, sensing coverage degradation caused by location error, packet loss and node failure is very limited, not more than 1%, as shown by our experimental results. We implement the proposed scheme in NS-2, as an extension of the LEACH protocol and compare its energy consumption with the original LEACH. Simulation results exhibit noticeably longer system lifetime with our scheme as compared to earlier algorithm. The first scheme we propose aims at completely preserving sensing coverage. This, however, requires each node to get, in some way, the knowledge of its own and its neighbors' location information. Also, in that scheme, each node has to perform some calculations to determine whether to take an off-duty status. To alleviate these restrictions, we propose and study several alternative node-scheduling schemes, which cannot guarantee the complete preservation of the original system coverage, but are nonetheless more light-weighted and flexible than the previous one. The simulation results compare these schemes with the previous one and demonstrate their effectiveness. In a single wireless sensor network, sensors are performing two operations: sensing and communication. Therefore, there might exist two kinds of redundancy in the network. Most of the previous work addressed only one kind of redundancy: sensing or communication alone. Although there have been research efforts trying to combine consideration of coverage and connectivity maintenance in a single activity scheduling, their theoretical basis for safe scheduling integration condition is only applicable in those networks that are initially fully covered by sensors. Random node deployment often makes initial sensing holes inside the deployed area inevitable, even in an extremely high-density network. Therefore, in this thesis, we enhance these works to support general wireless sensor networks by proving another conclusion: "the communication range is twice the sensing range" is the sufficient condition and the tight lower bound to ensure that complete coverage preservation implies connectivity among active nodes, if the original network topology (consisting of all the deployed nodes) is connected. Also, we extend the results to k-degree network connectivity and k-degree coverage preservation.
43
Kotari, Ravi Teja. "Node failure detection and data retrieval in wireless sensor networks". Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10108190.
Testo completoAbstract (sommario):
This project presents a method for detecting node failure in a wireless sensor network. The defective node is identified using round-trip delay measurements. Data transfer from the transmitter section to the receiver section is accomplished via the ZigBee protocol. As soon as a node has been identified as defective, the node is removed from the sensor network. Information about the failed node is provided to users with registered mobile device through the Global System for Mobile (GSM) module. The proposed method has been successfully implemented and tested experimentally on a small sensor network using the LPC2148 ARM7 microcontroller.
44
Ullah, Muhammad, e Waqar Ahmad. "Evaluation of Routing Protocols in Wireless Sensor Networks". Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2500.
Testo completoAbstract (sommario):
The evolution of wireless communication and circuit technology has enabled the development of an infrastructure consists of sensing, computation and communication units that makes administrator capable to observe and react to a phenomena in a particular environment. The building block of such an infrastructure is comprised of hundreds or thousands of small, low cost, multifunctional devices which have the ability to sense compute and communicate using short range transceivers known as sensor nodes. The interconnection of these nodes forming a network called wireless sensor network (WSN). The low cost, ease of deployment, ad hoc and multifunctional nature has exposed WSNs an attractive choice for numerous applications. The application domain of WSNs varies from environmental monitoring, to health care applications, to military operation, to transportation, to security applications, to weather forecasting, to real time tracking, to fire detection and so on. By considering its application areas WSN can be argue as a traditional wired or wireless network. But in reality, these networks are comprised of battery operated tiny nodes with limitations in their computation capabilities, memory, bandwidth, and hardware resulting in resource constrained WSN. The resource constrained nature of WSN impels various challenges in its design and operations degrading its performance. On the other hand, varying numbers of applications having different constraints in their nature makes it further challenging for such resources constrained networks to attain application expectations. These challenges can be seen at different layer of WSNs starting from physical layer up to application layer. At routing layer, routing protocols are mainly concerned with WSN operation. The presence of these challenges affects the performance of routing protocols resulting in overall WSN performance degradation. The aim of this study is to identify the performance challenges of WSN and analyze their impact on the performance of routing protocols. For this purpose a thorough literature study is performed to identify the issues affecting the routing protocols performance. Then to validate the impact of identified challenges from literature, an empirical study has been conducted by simulating different routing protocols, taking into consideration these challenges and results are shown. On the basis of achieved results from empirical study and literature review recommendations are made for better selection of protocol regarding to application nature in the presence of considered challenges.
45
Valderas, Núñez Darwin Abdon. "Integration of sensor nodes with IMS". Thesis, KTH, Kommunikationssystem, CoS, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91678.
Testo completoAbstract (sommario):
The number of users adopting cellular system technologies over the past years has been enormous. This rapid adoption is not comparable in any other technology. Additionally, this has meant that these users have (at least some of the time) the possibility of connectivity to others and to remote services (advanced data and voice services, such as video conferences, mobile TV, navigation, and location services). Increasingly there is no longer a clear boundary between the wide area cellular network and Internet services, as the wide area cellular network is evolving from circuit switched based technologies to an IP based system; hence these wide area cellular systems are simply becoming part of the Internet. This evolution has become a challenge for the telecommunication operators, who have been used to completely controlling their network services and billing. In an attempt to maintain this traditional role for telecommunication operators, telecommunication vendors have introduced the IP Multimedia Subsystem (IMS). A system designed to enable telecommunication operators to be able to bill the user for all of the different services accessed through the wide area cellular network. The goal of such a system is to prevent the telecommunication operators from becoming a "bit pipe" (i.e., simply providing "commodity priced" connectivity). Another relevant change that has direct impact upon this project is the role of mobile handsets as gateways between sensor networks and other networks (especially the wide area cellular networks or Internet). This has lead to integrated solutions, such as the smart house concept, mobile health monitoring, and others. This thesis project is a collaboration between Ericsson Research and SUUNTO, in which we have implemented a system for monitoring a user’s heart rate via IMS. The system (has a special focus on sports activities, but it could easily be adapted for health care) is based on internetworking sensor networks, specifically a heart rate belt that transmits data wirelessly, with the IMS network through a mobile phone or a PC. The implemented service runs on top of the SIP Presence service. This project examines two alternatives. The first is a mobile scenario, in which a person is jogging outdoors, in this setting the sensor node communicates via the person’s mobile phone, through the IMS network to a monitoring application. The second scenario is more fixed; such as a gym environment, where the sensor node communicates with a personal computer which in turn publishes the data via IMS. Once the data has been published to the Presence and group management sever, an application server subscribed to the athlete’s Presence service will be notified. The people interested in viewing this data will be able to see it through any web-browser. It will even be possible to archive, and download the data for later use by other applications. The system is not optimized yet for a truly real-time communication, as the Presence service does not offer this as other technologies (RTP, SRTP or XMPP) do. There is a big delay difference between the mobile and the fixed solution. We can say that the fixed solution is almost a real-time system for transmitting low frequency data as heart rate information. This project is a first approach to a final high performance system.Antalet användare som har fått tillgång till mobiltelefon under de senaste åren har varit enorm. Detta snabbt antagande är inte jämförbar med någon annan teknik. Dessutom innebär också detta att dessa användare har (åtminstone ibland) möjligheten till anslutning till andra och till avlägsna tjänster (avancerad data-och taltjänster, t.ex. videokonferenser, mobil TV, navigation och lokaliseringstjänster). Idags läget finns det inte längre en tydlig gräns mellan cellulära nätet och Internettjänster. Efter cellulära nätets utveckling från kretskopplad teknik till ett IP-baserat system, så håller dom cellulära systemem på att bli en del av Internet. Denna utveckling har blivit en utmaning för telekommunikationsföretag, som har varit vana att helt kontrollera sina nättjänster och fakturering. I ett försök att bevara denna traditionella roll för telekommunikationsföretag, har telekom-leverantörer infört IP Multimedia Subsystem (IMS). Ett system som syftar på att kunna göra telekommunikationsföretagen kapabla till att debitera användaren för alla dem olika tjänsterna som han har tillgång till via deras cellulära nät. Målet med ett sådant system är att förhindra telekommunikationsföretagen från att bli en "bit pipe" (dvs bara ge prissatt konnektivitet). En annan betydelsefull förändring som har direkt inverkan på detta projekt är den roll som mobiltelefoner kan utföra som gateways mellan sensornätverk och cellulära nät eller Internet. Detta har påverkat flera integrerade lösningar, såsom smarta hus begrepp, mobil hälsoövervakning och andra. Denna examensarbetes projekt är ett samarbete mellan Ericsson Research och Suunto, där vi har implementerat ett system för övervakning av en användares hjärtslag genom IMS. Systemet (har en särskild inriktning på sport, men det kan lätt anpassas för hälso-och sjukvård) är baserad på Internetworking sensornätverk, särskilt en hjärtfrekvens bälte som överför data trådlöst till en mobiltelefon eller en dator, som sedan skickar ut datan via IMS-nätverket. Tjänsten genomförs ovan på SIP Presence service. Projektet undersöker två alternativ. Den första är en mobil scenario; exempelvis där en person joggar utomhus, vid ett sådant tillfälle kommunicerar sensorn noden genom personens mobiltelefon, via IMS-nätverk med en övervaknings application. Det andra scenariot är mer statiskt och ger inte samma rörlighet, denna lösning passar bättre in på gym activiteter eller liknande. I denna implementering kommunicerar sensorn noden med en persondator som i sin tur publicerar uppgifterna via IMS. När uppgifterna har publicerats hos Presence and group management (PGM) servern. En applikations server som är uppskriven på att få friidrottarens närvaro tjänst kommer att meddelas. De människor som intresserade av att se denna data kommer att kunna göra det via någon webbläsare. Det kommer även att vara möjligt att arkivera och hämta datan för senare en användning men andra tillämpningar. Systemet är inte optimerad ännu för en verkligt realtid, eftersom Presence service inte erbjuder detta ännu som andra tekniker (RTP, SRTP eller XMPP) gör. Det finns en stor fördröjning skillnad mellan den mobila och fasta lösningen. Vi kan säga att den fasta lösningen är nästan ett realtids-system för överföring av lågfrekventa uppgifter som hjärtslag information. Detta projekt är en första strategi för en slutlig högpresterande system.
46
Ma, Aihui. "Synthesis and characterization of miniaturized fluorescence sensors for aqueous and cellular measurements". ScholarWorks@UNO, 2005. http://louisdl.louislibraries.org/u?/NOD,240.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of New Orleans, 2005.Title from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemistry."--Dissertation t.p. Vita. Includes bibliographical references.
47
Janansefat, Shadi. "Design and Implementation of Realistic and Terrain-aware Mobile Sensor Networks". OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1113.
Testo completoAbstract (sommario):
Wireless sensor networks (WSNs) have been used in many applications by deploying tiny and stationary sensors. In recent years, a lot of studies proposed to introduce mobility capability to sensor nodes in order to exploit the advantages of mobility, particularly to restore connectivity in disjoint WSNs. While the studies demonstrated various capabilities of the proposed connectivity algorithms via simulation, real node and testbed implementations were mostly lacking due to unavailability of proper mobile nodes. Since this may hinder the direct applicability of the algorithms in realistic settings, testbeds which can be constructed with low-cost and commercial-off-the-shelf (COTS) hardware are required for realistic evaluations of the connectivity restoration algorithms. In this thesis, we design a low-cost mobile sensor node called iRobotSense, by integrating iRobot Create platform with IRIS sensor. Then, a mobile sensor network (MSN) testbed of iRobotSense nodes is used to implement and evaluate a widely used connectivity restoration algorithms, namely PADRA. Furthermore, all of the previous works exploiting mobility of the nodes to achieve recovery in a partitioned network have assumed reachability of the nodes to the selected destinations via a direct path movement. However, in real-world applications, such assumption makes the schemes impractical in case of encountering obstacles or intolerable terrains. Besides, even if direct path movement is successful, optimal energy efficiency cannot be attained by neglecting the elevation or friction of the terrain. Thus, in the recovery efforts, terrain type, elevation as well as the obstacles should be taken into account. In this thesis, we re-design an existing connectivity restoration approach in disjoint MSNs to fit these requirements and evaluate the performance issues when realistic terrains are assumed. Rather than following a direct path, movement trajectory is determined based on a path planning algorithm which considers the risk and elevation of terrain sections to be visited while avoiding obstacles and highly elevated terrain sections.
48
Skelton, Adam W. "A New Wireless Sensor Node Design for Program Isolation and Power Flexibility". Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc28378/.
Testo completoAbstract (sommario):
Over-the-air programming systems for wireless sensor networks have drawbacks that stem from fundamental limitations in the hardware used in current sensor nodes. Also, advances in technology make it feasible to use capacitors as the sole energy storage mechanism for sensor nodes using energy harvesting, but most current designs require additional electronics. These two considerations led to the design of a new sensor node. A microcontroller was chosen that meets the Popek and Goldberg virtualization requirements. The hardware design for this new sensor node is presented, as well as a preliminary operating system. The prototypes are tested, and demonstrated to be sustainable with a capacitor and solar panel. The issue of capacitor leakage is considered and measured.
49
Mahrous, Hesham. "Energy efficient compression techniques for biological signals on a sensors node". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61057.
Testo completoAbstract (sommario):
Compression of biological signals is rapidly gaining much attention in research especially for Wireless Body Area Networks (WBANs) applications. This is because of their demonstrated potential in assisting physicians and patients, and helping them achieve a more convenient lifestyle. This work focuses on some problems arising in the deployment of EEG signals in WBANs where EEG data is collected and then transmitted using devices powered by batteries. To elongate the battery life, the energy consumed by acquiring, processing and transmitting the data has to be minimized. Lots of work using Compressed Sensing (CS) have addressed this problem and have demonstrated power savings in WBANs for applications such as Seizure detection. None of these studies however, have demonstrated a high quality signal recovery at high compression ratios such as 10:1. Higher quality signal recovery results in better performance for seizure detection. The ultimate goal is to achieve high quality recovery at high compression rates so as to elongate the battery life and without degrading the performance of WBAN applications. Two frameworks have been previously proposed to solve this problem. The first is a CS framework, which has an Analog to Digital Converter (ADC), micro-controller, and a low power transmitter at the sensor node. The second framework has an under-sampling circuit, an ADC, and a transmitter.
This thesis compares the results of the state of the art CS algorithms of both frameworks and demonstrates their performance in automatic seizure detection. Then it proposes two methods that achieve high quality signal recovery at high compression rates, for both frameworks. These methods are demonstrated on 3 different datasets. The first method, BSBL-LNLD is used for the CS framework. It exploits the linear and a non-linear dependency of multivariate EEG signals to recover the compressed signals. This method can achieve up to 0.06 Normalized Mean Square Error (NMSE) at 10:1 compression ratio. The second method solves the under-sampling CS framework using a Meyer wavelet over-complete dictionary by using the Analysis-Prior Formulation. This method achieves up to 0.18 NMSE at 10:1 compression ratio. The proposed methods achieve superb recovery quality and significantly decreased energy consumption.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
50
Maalel, Nourhene. "Reliability in wireless sensor networks". Thesis, Compiègne, 2014. http://www.theses.fr/2014COMP1944/document.
Testo completoAbstract (sommario):
Vu les perspectives qu'ils offrent, les réseaux de capteur sans fil (RCSF) ont perçu un grand engouement de la part de la communauté de recherche ces dernières années. Les RCSF couvrent une large gamme d'applications variant du contrôle d'environnement, le pistage de cible aux applications de santé. Les RCSFs sont souvent déployés aléatoirement. Ce dispersement des capteurs nécessite que les protocoles de transmission utilisés soient résistants aux conditions environnementales (fortes chaleurs ou pluies par exemple) et aux limitations de ressources des nœuds capteurs. En effet, la perte de plusieurs nœuds capteurs peut engendrer la perte de communication entre les différentes entités. Ces limitations peuvent causer la perte des paquets transmis ce qui entrave l'activité du réseau. Par conséquent, il est important d'assurer la fiabilité des transmissions de données dans les RCSF d'autant plus pour les applications critiques comme la détection d'incendies. Dans cette thèse, nous proposons une solution complète de transmission de données dans les RCSF répondant aux exigences et contraintes de ce type de réseau. Dans un premier temps, nous étudions les contraintes et les challenges liés à la fiabilisation des transmissions dans les RCSFs et nous examinons les travaux proposés dans la littérature. Suite à cette étude nous proposons COMN2, une approche distribuée et scalable permettant de faire face à la défaillance des nœuds. Ensuite, nous proposons un mécanisme de contrôle d'erreur minimisant la perte de paquets et proposant un routage adaptatif en fonction de la qualité du lien. Cette solution est basée sur des acquittements implicites (overhearing) pour la détection des pertes des paquets. Nous proposons ensuite ARRP une variante de AJIA combinant les avantages des retransmissions, de la collaboration des nœuds et des FEC. Enfin, nous simulons ces différentes solutions et vérifions leurs performances par rapport à leurs concurrents de l'état de l'artOver the past decades, we have witnessed a proliferation of potential application domainsfor wireless sensor networks (WSN). A comprehensive number of new services such asenvironment monitoring, target tracking, military surveillance and healthcare applicationshave arisen. These networked sensors are usually deployed randomly and left unattendedto perform their mission properly and efficiently. Meanwhile, sensors have to operate ina constrained environment with functional and operational challenges mainly related toresource limitations (energy supply, scarce computational abilities...) and to the noisyreal world of deployment. This harsh environment can cause packet loss or node failurewhich hamper the network activity. Thus, continuous delivery of data requires reliabledata transmission and adaptability to the dynamic environment. Ensuring network reliabilityis consequently a key concern in WSNs and it is even more important in emergencyapplication such disaster management application where reliable data delivery is the keysuccess factor. The main objective of this thesis is to design a reliable end to end solution for data transmission fulfilling the requirements of the constrained WSNs. We tackle two design issues namely recovery from node failure and packet losses and propose solutions to enhance the network reliability. We start by studying WSNs features with a focus on technical challenges and techniques of reliability in order to identify the open issues. Based on this study, we propose a scalable and distributed approach for network recovery from nodefailures in WSNs called CoMN2. Then, we present a lightweight mechanism for packetloss recovery and route quality awareness in WSNs called AJIA. This protocol exploitsthe overhearing feature characterizing the wireless channels as an implicit acknowledgment(ACK) mechanism. In addition, the protocol allows for an adaptive selection of therouting path by achieving required retransmissions on the most reliable link. We provethat AJIA outperforms its competitor AODV in term of delivery ratio in different channelconditions. Thereafter, we present ARRP, a variant of AJIA, combining the strengthsof retransmissions, node collaboration and Forward Error Correction (FEC) in order toprovide a reliable packet loss recovery scheme. We verify the efficiency of ARRP throughextensive simulations which proved its high reliability in comparison to its competitor