Dissertations / Theses on the topic 'Maritime wireless sensor networks'
To see the other types of publications on this topic, follow the link: Maritime wireless sensor networks.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Maritime wireless sensor networks.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Casias, Juan Francisco. "Performance of wireless unattended sensor networks in maritime applications." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Jun%5FCasias.pdf.
Full textAbstract:
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, June 2007.Thesis Advisor(s): John C. McEachen. "June 2007." Includes bibliographical references (p. 75 -79). Also available in print.
2
Yazar, Dogan. "RESTful Wireless Sensor Networks." Thesis, Uppsala University, Department of Information Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-110353.
Full textAbstract:
Sensor networks have diverse structures and generally employ proprietary protocols to gather useful information about the physical world. This diversity generates problems to interact with these sensors since custom APIs are needed which are tedious, error prone and have steep learning curve. In this thesis, I present RESThing, a lightweight REST framework for wireless sensor networks to ease the process of interacting with these sensors by making them accessible over the Web. I evaluate the system and show that it is feasible to support widely used and standard Web protocols in wireless sensor networks. Being able to integrate these tiny devices seamlessly into the global information medium, we can achieve the Web of Things.
3
Dogru, Sedat. "Sycophant Wireless Sensor Networks Tracked By Sparsemobile Wireless Sensor Networks While Cooperativelymapping An Area." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615139/index.pdf.
Full textAbstract:
In this thesis the novel concept of Sycophant Wireless Sensors (SWS) is introduced. A SWS network is a static ectoparasitic clandestine sensor network mounted incognito on a mobile agent using only the agent&rsquos mobility without intervention. SWS networks not only communicate with each other through mobileWireless Sensor Networks (WSN) but also cooperate with them to form a global hybrid Wireless Sensor Network. Such a hybrid network has its own problems and opportunities, some of which have been studied in this thesis work. Assuming that direct position measurements are not always feasible tracking performance of the sycophant using range only measurements for various communication intervals is studied. Then this framework was used to create a hybrid 2D map of the environment utilizing the capabilities of the mobile network the sycophant. In order to show possible applications of a sycophant deployment, the sycophant sensor node was equipped with a laser ranger as its sensor, and it was let to create a 2D map of its environment. This 2D map, which corresponds to a height dierent than the follower network, was merged with the 2D map of the mobile network forming a novel rough 3D map. Then by giving up from the need to properly localize the sycophant even when it is disconnected to the rest of the network, a full 3D map of the environment is obtained by fusing 2D map and tracking capabilities of the mobile network with the 2D vertical scans of the environment by the sycophant. And finally connectivity problems that arise from the hybrid sensor/actuator network were solved. For this 2 new connectivity maintenance algorithms, one based on the helix structures of the proteins, and the other based on the acute triangulation of the space forming a Gabriel Graph, were introduced. In this new algorithms emphasis has been given to sparseness in order to increase fault tolerance to regional problems. To better asses sparseness a new measure, called Resistance was introduced, as well as another called updistance.
4
Chraibi, Youssef. "Localization in Wireless Sensor Networks." Thesis, KTH, Reglerteknik, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-107528.
Full textAbstract:
Similar to many technological developments, wireless sensor networks have emerged from military needs and found its way into civil applications. Today, wireless sensor networks has become a key technology for different types of ”smart environments”, and an intense research effort is currently underway to enable the application of wireless sensor networks for a wide rangeof industrial problems. Wireless networks are of particular importance whena large number of sensor nodes have to be deployed, and/or in hazardous situations. Localization is important when there is an uncertainty of the exact location of some fixed or mobile devices. One example has been in the supervision of humidity and temperature in forests and/or fields, where thousands of sensors are deployed by a plane, giving the operator little or no possibility to influence the precise location of each node. An effective localization algorithm can then use all the available information from the wireless sensor nodes to infer the position of the individual devices. Another application is the positioning of a mobile robot based on received signal strength from a set of radio beacons placed at known locations on the factory floor. This thesis work is carried out on the wireless automation testbed at the S3. Focusing on localization processes, we will first give an overview of the state of the art in this area. From the various techniques, one idea was found to have significant bearing for the development of a new algorithm. We present analysis and simulations of the algorithms, demonstrating improved accuracy compared to other schemes although the accuracy is probably not good enough for some high-end applications. A third aspect of the work concerns the feasibility of approaches based on received signal strength indication (RSSI). Multiple measurement series have been collected in the lab with the MoteIV wireless sensor node platform. The measurement campaign indicates significant fluctuations in the RSSI values due to interference and limited repeatability of experiments, which may limit the reliability of many localization schemes, especially in an indoor environment.
5
Cao, Hui. "Stabilization in wireless sensor networks." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1211079872.
Full text
6
Tseng, Kuan-Chieh Robert. "Resilience of wireless sensor networks." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/33713.
Full textAbstract:
The coverage of a wireless sensor network is a measure of the quality of service. One type of coverage is k-barrier coverage. Given a starting region S and an ending region T , we say that a sensor network has k-barrier coverage with respect to S and T if any S−T path in the surveillance domain must intersect the coverage regions of at least k sensors.
In this thesis, we focus on determining the resilience of a wireless sensor network. The resilience is defined to be the minimum number of sensors that need to be removed in order to ensure the existence of a S−T path that does not cross any sensor coverage region. A sensor network with resilience k constitutes a k-barrier coverage.
We demonstrate that determining resilience of a wireless sensor network with 2D surveillance domain is NP-hard for the case when the sensor coverage regions are unit line segments. Furthermore, it is possible to extend the reduction to show that the problem remains NP-hard for other types of sensor coverage regions. In general, if the shape of the coverage region is non-symmetric, then determining resilience is NP-hard.
We also investigate the problem of determining resilience of a wireless sensor network with 3D surveillance domain. In this case, we show that if the coverage regions of the sensors are unit spheres, then the problem is NP-hard.
7
Saif, Waleed Abdulwahed. "Localization in wireless sensor networks." Thesis, University of Leeds, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555845.
Full textAbstract:
In this thesis we examine localization in wireless sensor networks starting with a brief overview of the basics of radiolocation techniques and then look at some of the most well-known commercial positioning techniques and localization algorithms. We then concentrate on the application of the Fastmap (FM) algorithm in the field of wireless sensor localization. Our first contribution in this thesis is the mathematical analysis of the FM algorithm in terms of the mean squared error (MSE) of the coordinate estimate under a multiplicative noise model followed by the optimum placement of anchor nodes. The algorithm is compared to Linear Least Squares (LLS) algorithm, which is well known and has a similar complexity to that of FM. Another contribution is proposing the angle-projected FM algorithm for wireless sensor nodes localization in order to enhance the connectivity of the network and the overall performance. A comprehensive study and mathematical analysis in terms of the MSE for this algorithm is presented and it is also compared with the original FM algorithm. We also propose a weighted Fastmap (WFM) algorithm in which more than one pair of anchor nodes is used to evaluate the first coordinate (i.e., x-coordinate) of the unknown nodes in order to reduce the effect of error dependency in the y-coordinate estimation. (In the original FM algorithm only one pair of anchor nodes was employed.) The optimal WFM weights are determined via (constrained) minimization of the MSE of the estimated node coordinates. A simplification of the WFM is also introduced, called the averaged FM (AFM), where complexity is reduced at the expense of degradation in the overall WFM performance. Both the WFM and AFM exhibit improved performance over the original FM algorithm. Finally, an unbiased version of the WFM, AFM and FM is presented in which an estimate of the bias term is removed to improve the overall MSE performance. The effect of this modification on the algorithms' performance is then analysed and discussed.
8
Li, Wei. "Cooperation arrayed wireless sensor networks." Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.536033.
Full text
9
Peng, Wei. "Optimisation of wireless sensor networks." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543734.
Full text
10
Cheng, King-yip, and 鄭勁業. "Localization in wireless sensor networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38700189.
Full text
11
Goh, Hock Guan. "Cognitive wireless sensor networks (CogWSNs)." Thesis, University of Strathclyde, 2014. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24216.
Full textAbstract:
Cognitive Wireless Sensor Networks (CogWSNs) are an adaptive learning based wireless sensor network relying on cognitive computational processes to provide a dynamic capability in configuring the network. The network is formed by sensor nodes equipped with cognitive modules with awareness of their operating environment. If the performance of the sensor network does not meet requirements during operation, a corrective action is derived from stored network knowledge to improve performance. After the action is implemented, feedback on the action taken is evaluated to determine the level of improvement. Example functions within CogWSNs can be as simple as to provide robust connectivity or as complex as to negotiate additional resources from neighbouring network groups with the goal of forwarding application-critical data. In this work, the concept of CogWSNs is defined and its decision processes and supporting architecture proposed. The decision role combines the Problem Solving cognitive process from A Layered Reference Model of the Brain and Polya Concept, consisting of Observe, Plan, Implement, and Evaluate phases. The architecture comprises a Transceiver, Transducer, and Power Supply virtual modules coordinated by the CogWSN's decision process together with intervention, if necessary, by a user. Three types of CogWSN modules are designed based on different implementation considerations: Rule-based CogWSN, Supervised CogWSN, and Reinforcement CogWSN. Verification and comparison for these modules are executed through case studies with focus on power transmission and communication slot allocation. Results show that all three modules are able to achieve targeted connectivity and maintain utilisation of slots at acceptable data rates.
12
Krol, Michal. "Routin in wireless sensor networks." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAM004/document.
Full textAbstract:
Le paradigme d’Internet des objets (IoT) envisage d’élargir Internet actuelle avec un grand nombre de dispositifs intelligents. Réseaux de Capteurs sans Fil (WSN) déploie les dispositifs fonctionnant sur des approvisionnements énergétiques maigres et mesurant de phénomènes environnementaux (comme la température, la radioactivité, ou CO 2). Des applications populaires de WSN comprennent la surveillance, le télémétrie, et la prévention des catastrophes naturelles. Des défis majeurs de WSN sont comment permettre à l’efficacité énergétique, surmonter les déficiences de support sans fil, et d’opérer dans à la manière auto-organisée. L’intégration de WSN dans IoT se posera sur des standards ouvertes efforçant d’offrir évolutivité et de fiabilité dans une variété de scénarios et conditions de fonctionnement. Néanmoins, l’état actuel des standards a les problèmes d’interopérabilité et peuvent bénéficier de certaines améliorations. Les contributions de la thèse sont :Nous avons effectué une étude approfondie des filtres de Bloom et de leur utilisation dans le stockage de caractéristiques de nœud dans l’adresse IP. Différentes techniques de compression et de variantes de filtres nous ont permisde développer un système efficace qui comble l’écart entre le routage de caractéristiques et l’approche classique compatible avec les réseaux IPv6.Nous proposons Featurecast, un protocole de routage / service de nommage pourWSN. Il permet d’interroger les réseaux de capteurs en utilisant un ensemble de caractéristiques tout raccord en entête de paquet IPv6. Nous intégrons notre protocole dans RPL et introduisons une nouvelle mesure, qui augmentent l’efficacité de routage. Nous vérifions sa performance contre dans des simulations approfondies et des test sur des capteurs réels dans un bancd’essai à grande échelle. Simulations approfondies démontrent les avantagesde notre protocole en termes d’utilisation de la mémoire, le surcharge de con-trôle, le taux de livraison de paquets et la consommation d’énergie.Nous introduisons WEAVE - un protocole de routage pour les réseaux avec géolo-calisation. Notre solution n’utilise pas de message de contrôle et apprend sesvoies seulement en observant le trafic. Plusieurs mécanismes sont introduitspour garder un en-tête de taille fixe, contourner à la fois les petits commeles grands obstacles et fournir une communication efficace entre les nœuds.Nous avons effectué des simulations à grande échelle impliquant plus de 19000noeuds et des expériences avec des capteurs réels sur banc d’essai IoT-lab.Nos résultats montrent que nous atteignons bien meilleures performances enparticulier dans les réseaux grands et dynamiques sans introduire de surchargeInternet of Things (IoT) paradigm envisages to expand the current Internet witha huge number of intelligent communicating devices. Wireless Sensor Networks(WSN) deploy the devices running on meagre energy supplies and measuring environmental phenomena (like temperature, radioactivity, or CO 2 ). WSN popularapplications include monitoring, telemetry, and natural disaster prevention. Major WSN challenges are energy efficiency, overcome impairments of wireless medium, and operate in the self-organisation. The WSN integrating IoT will rely on a set of the open standards striving to offer scalability and reliability in a variety of the operating scenarios and conditions. Nevertheless, the current state of the standards have interoperability issues and can benefit from further improvements. The contributions of the thesis work are:We performed an extensive study of Bloom Filters and their use in storing nodetext-based elements in IP address. Different techniques of compression andvariants of filters allowed us to develop an efficient system closing the gapbetween feature-routing and classic approach compatible with IPv6 networks.We propose Featurecast, a routing protocol/naming service for WSN. It allowsto query sensor networks using a set of characteristics while fitting in anIPv6 packet header. We integrate our protocol in RPL and introduce a newmetric, which increase the routing efficiency. We check its performance inboth extensive simulations and experimentations on real sensors in a large-scale Senslab testbed. Large-scale simulations demonstrate the advantagesof our protocol in terms of memory usage, control overhead, packet deliveryrate and energy consumption.We introduce WEAVE - a routing protocol for networks with geolocation. Our so-lution does not use any control message and learn its paths only by observingthe traffic. Several mechanisms are introduce to keep a fixed-size header andbypass both small as well as large obstacles and provide an efficient communication between nodes. We performed simulations on large scale involvingmore than 19000 nodes and real-sensor experimentations on IoT-lab testbed. Our results show that we achieve much better performance especially in large and dynamic networks without introducing any control overhead
13
Maalel, Nourhene. "Reliability in wireless sensor networks." Thesis, Compiègne, 2014. http://www.theses.fr/2014COMP1944/document.
Full textAbstract:
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
14
Kordari, Kamiar. "Self organizing wireless sensor networks." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7625.
Full textAbstract:
Thesis (Ph. D.) -- University of Maryland, College Park, 2007.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.
15
Meier, Andreas. "Safety critical wireless sensor networks." Aachen Shaker, 2009. http://d-nb.info/997314435/04.
Full text
16
Fairbairn, M. L. "Dependability of wireless sensor networks." Thesis, University of York, 2014. http://etheses.whiterose.ac.uk/8205/.
Full textAbstract:
As wireless sensor networks (WSNs) are becoming ever more prevalent, the runtime characteristics of these networks are becoming an increasing issue. Commonly, external sources of interference make WSNs behave in a different manner to that expected from within simplistic simulations, resulting in the need to use additional systems which monitor the state of the network. Despite dependability of WSNs being an increasingly important issue, there are still only a limited number of works within this specific field, with the majority of works focusing on ensuring that specific devices are operational, not the application as a whole. This work instead aims to look at the dependability of WSNs from an application-centric view, taking into account the possible ways in which the application may fail and using the application's requirements to focus on assuring dependability.
17
Sriporamanont, Thammakit, and Gu Liming. "Wireless Sensor Network Simulator." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-290.
Full textAbstract:
In the recent past, wireless sensor networks have been introduced to use in many applications. To
design the networks, the factors needed to be considered are the coverage area, mobility, power
consumption, communication capabilities etc. The challenging goal of our project is to create a
simulator to support the wireless sensor network simulation. The network simulator (NS-2) which
supports both wire and wireless networks is implemented to be used with the wireless sensor
network. This implementation adds the sensor network classes which are environment, sensor
agent and sensor application classes and modifies the existing classes of wireless network in NS-
2. This NS-2 based simulator is used to test routing protocols – Destination-Sequenced Distance
Vector (DSDV), and Ad-Hoc On-Demand Distance Vector (AODV) as one part of simulations.
Finally, the sensor network application models and the extension methods of this NS-2 based
simulator for simulations in specific wireless sensor network applications are proposed.
18
Salatas, Vlasios. "Object tracking using wireless sensor networks." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Sep%5FSalatas.pdf.
Full textAbstract:
Thesis (M.S. in Computer Science)--Naval Postgraduate School, September 2005.Thesis Advisor(s): Gurminder Singh, Arijit Das. Includes bibliographical references (p. 271-273). Also available online.
19
Calabrese, Giovanni. "Wireless Sensor Networks: An Industrial Approach." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Find full textAbstract:
The goal of this project is to create a Wireless Sensor Network (WSN) within a company.We will then talk about WSN within Industry 4.0. The company has a large productionwarehouse, where numerous machines form their production process. Currently, theproduction machines are disconnected from the data network, so everything that happensmust be manually verified by the operators.It will need to connect the machines to the network to make the production processinnovative. The choice of technologies to be used will fall on wireless technologies, whichhave numerous advantages: not laying cables, being able to create various types ofnetworks and quickly connecting many machines. During the project, it will look for thebest solutions to interconnect the machines, selecting specific devices able to satisfy allrequests.The reference scenario is a production warehouse of a company operating in themetalworking sector. Inside the warehouse, there are numerous production machines,which form a heterogeneous machine park. All these machines, which have no possibilityof data exchange, must be equipped with devices capable of communicating the extracteddata.As the reference scenario is an industrial production warehouse, it can speak of In-dustry 4.0.Various communication technologies will be studied, to update the machines to havea digital representation of the production process. These communication technologieswill be partially wireless, in particular for devices to be attached to the machines, andpartly wired, to interface with the external network.It will see how it is possible to extract data from the machines, send them via devicesto a central node, which will process them to give a digital vision of the production.
20
Tan, Kok Sin Stephen. "Source localization using wireless sensor networks." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Jun%5FTan.pdf.
Full textAbstract:
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, June 2006.Thesis Advisor(s): Murali Tummala, John McEachen. "June 2006." Includes bibliographical references (p. 77-78). Also available in print.
21
Barros, João. "Reachback communication in wireless sensor networks." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973065753.
Full text
22
Kirykos, Georgios. "Traffic profiling of wireless sensor networks." Thesis, Monterey, Calif. : Naval Postgraduate School, 2006. http://bosun.nps.edu/uhtbin/hyperion.exe/06Dec%5FKirykos.pdf.
Full textAbstract:
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, December 2006.Thesis Advisor(s): John C. McEachen. "December 2006." Includes bibliographical references (p.65-66). Also available in print.
23
Zhang, Hongwei. "Dependable messaging in wireless sensor networks." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1155607973.
Full text
24
Li, Qian. "Cooperating Tools for Wireless Sensor Networks." Thesis, Uppsala University, Department of Information Technology, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-129466.
Full textAbstract:
Wireless Sensor Network (WSN) simulators, testbeds, and environment simulators are indispensable tools for WSN research. Existing WSN tools were developed with different purposes without the intention of cooperation. Nevertheless, the development of a WSN technology (e.g, a middleware, a protocol, or an application) usually requires the cooperation among multiple tools. This calls upon a breaking of the incompatible barriers between any pair of tools.
In this thesis, I propose the Common Input and Output integration approach (the CIO approach). This approach attempts to define a standard configuration file format containing input and output data common to WSN tools. In hope that by supporting this standard configuration file format, tools can cooperate. The WiseML [23] format defined by the WISEBED [29] project is fully in compliance with the requirement of the CIO format. Therefore, it is chosen as a concrete representation of the CIO format.
To evaluate the CIO approach, I developed a bidirectional online converter for one of the WSN simulators - COOJA [42]. The converter is capable of converting between the WiseML format and COOJA's native CSC format on-the-fly. It provides not only the support for both the input and output of the WiseML format but also the functionality of converting the text format temperature log file generated by testbeds to WiseML format.
While I was working on this work, a number of other international organizations were also adding WiseML supports to their own tools. We exchanged our WiseML files and observed gratifying results: (1) WSN simulators can load each other's WiseML files and reproduce the same network topologies and scenarios in their own simulation frameworks; (2) The WiseML format scenarios generated by testbeds and environment simulators can be directly inserted into a WiseML file, and take effect during simulations; (3) The time and space overheads of the converter is acceptable and proportional to the complexity of a simulation. A WiseML file of a few hundreds KB and a format converting time of a few hundreds milliseconds can meet the requirements of most of the simulations. For example, a WiseML file containing 800 motes without scenario and trace sections has a size of approximately 200 KB, and a format converting time of around 500 milliseconds.
25
Ogunlu, Bilal. "Lifetime Analysis For Wireless Sensor Networks." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605226/index.pdf.
Full textAbstract:
Sensor technologies are vital today in gathering information about certain environments and wireless sensor networks are getting more widespread use everyday. These networks are characterized by a number of sensor nodes deployed in the field for the observation of some phenomena. Due to the limited battery capacity in sensor nodes, energy efficiency is a major and challenging problem in such power-constrained networks. Some of the network design parameters have a direct impact on the network&rsquos lifetime. These parameters have to be chosen in such a way that the network use its energy resources efficiently. This thesis studies these parameters that should be selected according to certain trade offs with respect to the network&rsquo
s lifetime. In this work, these trade offs have been investigated and illustrated in detail in various combinations. To achieve this goal, a special simulation tool has been designed and implemented in this work that helps in analyzing the effects of the selected parameters on sensor network&rsquo
s lifetime. OMNeT++, a discrete event simulator, provides the framework for the sensor network simulator&rsquo
s development. Ultimately, results of extensive computational tests are presented, which may be helpful in guiding the sensor network designers in optimally selecting the network parameters for prolonged lifetime.
26
Khan, Muhammad Waqas. "Optimised localisation in wireless sensor networks." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/13399/.
Full textAbstract:
Wireless sensor networks (WSNs) comprise of tens, hundreds or thousands of low powered, low cost wireless nodes, capable of sensing environmental data such as humidity and temperature. Other than these sensing abilities, these nodes are also able to locate themselves. Different techniques can be found in literature to localise wireless nodes in WSNs. These localisation algorithms are based on the distance estimates between the nodes, the angle estimates between the nodes or hybrid schemes. In the context of range based algorithms, two prime techniques based on the time of arrival (ToA) and the received signal strength (RSS) are commonly used. On the other hand, angle based approach is based on the angle of arrival (AoA) of the signal. A hybrid approach is sometimes used to localise wireless nodes. Hybrid algorithms are more accurate than range and angle based algorithms because of additional observations. Modern WSNs consist of a small group of highly resourced wireless nodes with known locations called anchor nodes (ANs) and a large group of low resourced wireless nodes known as the target nodes (TNs). The ANs can locate themselves through GPS or they may have a predetermined location given to them during network deployment. Based on these known locations and the range/angle estimates, the TNs are localised. Since hybrid algorithms (a combination of RSS, ToA and AoA) are more accurate than other algorithms, a major portion of this thesis will focus on these approaches. Two prime hybrid signal models are discussed: i) The AoA-RSS hybrid model and ii) the AoA-ToA hybrid signal model. A hybrid AoA-ToA model is first studied and is further improved by making the model unbiased and by developing a new weighted linear least squares algorithm for AoA-ToA signal (WLLS-AoA-ToA) that capitalise on the covariance matrix of the incoming signal. A similar approach is taken in deriving a WLLS algorithm for AoA-RSS signal (WLLS-AoA-RSS). Moreover expressions of theoretical mean square error (MSE) of the location estimate for both signal models are derived. Performances of both signal models are further improved by designing an optimum anchor selection (OAS) criterion for AoA-ToA signal model and a two step optimum anchor selection (TSOAS) criterion for AoA-RSS signal model. To bound the performance of WLLS algorithms linear Cramer Rao bounds (LCRB) are derived for both models, which will be referred to as LCRB-AoA-ToA and LCRB-AoA-RSS, for AoA-ToA and AoA-RSS signal models, respectively. These hybrid localisation schemes are taken one step further and a cooperative version of these algorithms (LLS-Coop) is designed. The cooperation between the TNs significantly improves the accuracy of final estimates. However this comes at a cost that not only the ANs but the TNs must also be able to estimate AoA and ToA/RSS simultaneously. Thus another version of the same cooperative model is designed (LLS-Coop-X) which eliminates the necessity of simultaneous angle-range estimation by TNs. A third version of cooperative model is also proposed (LLS-Opt-Coop) that capitalises the covariance matrix of incoming signal for performance improvement. Moreover complexity analysis is done for all three versions of the cooperative schemes and is compared with its non cooperative counterparts. In order to extract the distance estimate from the RSS the correct knowledge of path-loss exponent (PLE) is required. In most of the studies this PLE is assumed to be accurately known, also the same and fixed PLE value is used for all communication links. This is an oversimplification of real conditions. Thus error analysis of location estimates with incorrect PLE assumptions for LLS technique is done in their respective chapters. Moreover a mobile TN and an unknown PLE vector is considered which is changing continuously due to the motion of TN. Thus the PLE vector is first estimated using the generalized pattern search (GenPS) followed by the tracking of TN via the Kalman filter (KF) and the particle filter (PF). The performance comparison in terms of root mean square error (RMSE) is also done for KF, extended Kalman filter (EKF) and PF.
27
Lv, Xiaowei. "Indoor localization in wireless sensor networks." Thesis, Troyes, 2015. http://www.theses.fr/2015TROY0009/document.
Full textAbstract:
Ce manuscrit est dédié à la résolution du problème de localisation dans les réseaux de capteurs sans fil mobiles. Les méthodes développées se basent principalement sur des caractéristiques de fingerprints ainsi que sur des informations de mobilité. Les premières s'attaquent aux valeurs de RSSI entre capteurs tandis que les deuxièmes prennent en considération la mobilité des capteurs mesurée à l'aide d'accéléromètres et de gyroscopes. La combinaison des données collectées est effectuée dans le cadre de l'analyse par intervalles, ou bien du filtrage de Kalman. Les travaux proposés introduisent des modèles de mobilité d'ordres un, deux ou trois, permettant d'approximer au mieux les trajectoires des capteurs à l'aide des accélérations mesurées. Ceux-là sont couplés à l'algorithme des K plus proches voisins, d'abord dans un système centralisé. Ensuite, les modèles de mobilités sont améliorés pour prendre en compte les rotations des nœuds. Une méthode de localisation décentralisée est également proposée dans ce qui suit, s'adaptant au mécanisme fonctionnel des réseaux de capteurs de grande échelle. Enfin, ce manuscrit propose une méthode de zonage visant à déterminer les zones dans lesquelles les capteurs résident. La méthode proposée aborde le problème de zonage en utilisant à la fois la théorie des fonctions de croyance et l'analyse par intervallesThis thesis is dedicated to solve the localization problem in mobile wireless sensor networks. It works mainly with fingerprints features and inertial movements information. The former tackles the RSSIs values between sensors while the latter deals with the objets movement attitude by using accelerometer and gyroscope. The combination of both information is performed in terms of interval analysis, or Kalman filtering. The proposed work introduces three orders mobility models to approximate nodes trajectories using accelerations, combined then to the weighted K nearest neighbors algorithm in a centralized scheme. Then the mobility models are extended up to the inertial information taking into consideration the rotations of the nodes. A decentralized localization method is also proposed in the following in view of the working mechanism of large scale sensor networks. Finally, this thesis proposes a zoning localization method aiming at determining the zones in which the nodes reside. The proposed method addresses the zoning problem by using both the belief functions theory and the interval analysis
28
Cui, Jin. "Data aggregation in wireless sensor networks." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI065/document.
Full textAbstract:
Depuis plusieurs années, l’agrégation de données sont considérés comme un domaine émergent et prometteur tant dans le milieu universitaire que dans l’industrie. L’énergie et la capacité du réseau seront donc économisées car il y aura moins de transmissions de données. Le travail de cette thèse s’intéresse principalement aux fonctions d’agrégation Nous faisons quatre contributions principales. Tout d’abord, nous proposons deux nouvelles métriques pour évaluer les performances des fonctions d’agrégations vue au niveau réseau : le taux d’agrégation et le facteur d’accroissement de la taille des paquets. Le taux d’agrégation est utilisé pour mesurer le gain de paquets non transmis grâce à l’agrégation tandis que le facteur d’accroissement de la taille des paquets permet d’évaluer la variation de la taille des paquets en fonction des politiques d’agrégation. Ces métriques permettent de quantifier l’apport de l’agrégation dans l’économie d’énergie et de la capacité utilisée en fonction du protocole de routage considéré et de la couche MAC retenue. Deuxièmement, pour réduire l’impact des données brutes collectées par les capteurs, nous proposons une méthode d’agrégation de données indépendante de la mesure physique et basée sur les tendances d’évolution des données. Nous montrons que cette méthode permet de faire une agrégation spatiale efficace tout en améliorant la fidélité des données agrégées. En troisième lieu, et parce que dans la plupart des travaux de la littérature, une hypothèse sur le comportement de l’application et/ou la topologie du réseau est toujours sous-entendue, nous proposons une nouvelle fonction d’agrégation agnostique de l’application et des données devant être collectées. Cette fonction est capable de s’adapter aux données mesurées et à leurs évolutions dynamiques. Enfin, nous nous intéressons aux outils pour proposer une classification des fonctions d’agrégation. Autrement dit, considérant une application donnée et une précision cible, comment choisir les meilleures fonctions d’agrégations en termes de performances. Les métriques, que nous avons proposé, sont utilisées pour mesurer la performance de la fonction, et un processus de décision markovien est utilisé pour les mesurer. Comment caractériser un ensemble de données est également discuté. Une classification est proposée dans un cadre précisWireless Sensor Networks (WSNs) have been regarded as an emerging and promising field in both academia and industry. Currently, such networks are deployed due to their unique properties, such as self-organization and ease of deployment. However, there are still some technical challenges needed to be addressed, such as energy and network capacity constraints. Data aggregation, as a fundamental solution, processes information at sensor level as a useful digest, and only transmits the digest to the sink. The energy and capacity consumptions are reduced due to less data packets transmission. As a key category of data aggregation, aggregation function, solving how to aggregate information at sensor level, is investigated in this thesis. We make four main contributions: firstly, we propose two new networking-oriented metrics to evaluate the performance of aggregation function: aggregation ratio and packet size coefficient. Aggregation ratio is used to measure the energy saving by data aggregation, and packet size coefficient allows to evaluate the network capacity change due to data aggregation. Using these metrics, we confirm that data aggregation saves energy and capacity whatever the routing or MAC protocol is used. Secondly, to reduce the impact of sensitive raw data, we propose a data-independent aggregation method which benefits from similar data evolution and achieves better recovered fidelity. Thirdly, a property-independent aggregation function is proposed to adapt the dynamic data variations. Comparing to other functions, our proposal can fit the latest raw data better and achieve real adaptability without assumption about the application and the network topology. Finally, considering a given application, a target accuracy, we classify the forecasting aggregation functions by their performances. The networking-oriented metrics are used to measure the function performance, and a Markov Decision Process is used to compute them. Dataset characterization and classification framework are also presented to guide researcher and engineer to select an appropriate functions under specific requirements
29
Yoon, Suyoung. "Power Management in Wireless Sensor Networks." NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-01232007-222425/.
Full textAbstract:
One of the unique characteristics of wireless sensor networks (WSNs) is that sensor nodes have very constrained resources. Typical sensor nodes have lower computing power, communication bandwidth, and smaller memory than other wireless devices, and operate on limited capacity batteries. Hence power efficiency is very important in WSNs because power failure of some sensor nodes may lead to total network failure. In many cases the WSNs have to operate in harsh environments without human intervention for expended period time. Thus, much research on reducing or minimizing the power consumption, and thereby increasing the network lifetime, has been performed at each layer of the network layers. In this dissertation we approach three important issues related power management in WSNs: routing, time synchronization, and medium access control (MAC). We first discuss the effect of selecting routing protocols on the lifetime of the WSNs. The maximum and minimum bounds of the lifetime with respect to the routing protocols are derived. The routing protocols corresponding to the bounds are also presented. The simulation results show that the choice of the routing protocol has very little impact on the lifetime of the network and that simple routing protocols such as shortest path routing perform very close to the the maximum bound of the lifetime of the network. Next, we propose a simple and accurate time synchronization protocol that can be used a a fundamental component of other synchronization-based protocols in WSNs. Analytical bounds on the synchronization errors of proposed protocol are discussed. The implementation results on Mica2 and Telos motes show that proposed time synchronization protocol outperforms existing ones in terms of the precision and required resources. Finally, we model the power consumption of WSN MAC protocols. We derive analytically the power consumption of well known MAC protocols for WSNs, and analyze and compare their performance. We validate the models by measuring the power consumption on Mica 2 motes and comparing those measured power consumption with the analytical results.
30
Borbash, Steven A. "Design considerations in wireless sensor networks." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1764.
Full textAbstract:
Thesis (Ph. D.) -- University of Maryland, College Park, 2004.Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
31
Prasad, Pratap Simha. "Energy efficiency in wireless sensor networks." Auburn, Ala., 2007. http://repo.lib.auburn.edu/2007%20Spring%20Theses/PRASAD_PRATAP_30.pdf.
Full text
32
Ren, Kui. "Communication security in wireless sensor networks." Worcester, Mass. : Worcester Polytechnic Institute, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-040607-174308/.
Full text
33
Chow, Kit-yee. "Angle coverage in wireless sensor networks." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39341835.
Full text
34
Zhuang, Yongzhen. "Intelligent sampling over wireless sensor networks /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?CSED%202008%20ZHUANG.
Full text
35
Murukesvan, Abhinash. "Distributed Overlays in Wireless Sensor Networks." Thesis, KTH, Kommunikationssystem, CoS, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92202.
Full textAbstract:
This thesis investigates two architectures and compares their suitability for selective application and user differentiation in sensor networks. A hierarchical architecture consisting of more capable cluster heads surrounded by weaker nodes is compared to a flat architecture of equally powerful nodes. In both architectures there exists a logical overlay network that connects the nodes, depending on the application and user. Furthermore, a broadcast encryption scheme is proposed to aid in distributing keys to nodes for secure communication and to maintain these restricted groups.applikation och användar differentiering i trådlösa sensor nätverk. En hierarkisk arkitekturbestående av kraftfullare sensor noder omgiven av mindre kraftfulla sensor noder jämförsmed en platt arkitektur bestående av lika kraftfulla sensor noder. I båda arkitekturer existerarett logiskt lager ovanpå stacken som kopplar noder beroende på applikation och användare,helt oberoende av geografisk placering. Utöver det, bör en nyckel management schema användas till att distribuera nycklar tillnoderna för säker kommunikation och att bibehålla dessa slutna grupper.
36
Gupta, Ashish. "Empirical analysis of wireless sensor networks." Phd thesis, Institut National des Télécommunications, 2010. http://tel.archives-ouvertes.fr/tel-00589606.
Full textAbstract:
Wireless sensor networks are the collection of wireless nodes that are deployed to monitor certain phenomena of interest. Once the node takes measurements it transmits to a base station over a wireless channel. The base station collects data from all the nodes and do further analysis. To save energy, it is often useful to build clusters, and the head of each cluster communicates with the base station. Initially, we do the simulation analysis of the Zigbee networks where few nodes are more powerful than the other nodes. The results show that in the mobile heterogeneous sensor networks, due to phenomenon orphaning and high cost of route discovery and maintenance, the performance of the network degrades with respect to the homogeneous network. The core of this thesis is to empirically analyze the sensor network. Due to its resource constraints, low power wireless sensor networks face several technical challenges. Many protocols work well on simulators but do not act as we expect in the actual deployments. For example, sensors physically placed at the top of the heap experience Free Space propagation model, while the sensors which are at the bottom of the heap have sharp fading channel characteristics. In this thesis, we show that impact of asymmetric links in the wireless sensor network topology and that link quality between sensors varies consistently. We propose two ways to improve the performance of Link Quality Indicator (LQI) based algorithms in the real asymmetric link sensor networks. In the first way, network has no choice but to have some sensors which can transmit over the larger distance and become cluster heads. The number of cluster heads can be given by Matérn Hard-Core process. In the second solution, we propose HybridLQI which improves the performance of LQI based algorithm without adding any overhead on the network. Later, we apply theoretical clustering approaches in sensor network to real world. We deploy Matérn Hard Core Process and Max-Min cluster Formation heuristic on real Tmote nodes in sparse as well as highly dense networks. Empirical results show clustering process based on Matérn Hard Core Process outperforms Max-Min Cluster formation in terms of the memory requirement, ease of implementation and number of messages needed for clustering. Finally, using Absorbing Markov chain and measurements we study the performance of load balancing techniques in real sensor networks.
37
Abebe, Zelalem Teffera. "Process Control over Wireless Sensor Networks." Thesis, KTH, Reglerteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-133584.
Full textAbstract:
A signicant growth was witnessed in the led of Wireless Sensor Networks (WSNs), the previous decade. Advances in hardware miniaturization coupled with increased processing capabilities and memory capacity have extended the application domains of WSNs. In light of this, standardization organizations led by academia and industries initiated activities for the design of protocols such as IEEE 802.15.4 and IETF RPL (Routing Protocol for Low power and Lossy Networks). IEEE 802.15.4 denes physical and media access layers for WSNs while IETF RPL denes the functionality of the routing layer. This thesis investigates research issues in wireless sensor networks and network controlled systems that control micro-biological processes for water treatment plants. By choosing a process model that can relate to an industrial process, feasibility of control over IEEE 802.15.4 and RPL protocols is evaluated for stability with regards to network delay and packet loss. Settling time and overshoot are measured to indicate control performance. Control messages related to routing and routing table lengths are measured to indicate network stability and scalability. The system model used is a centralized discrete controller controlling a thermal processes running on the sensors. This model is chosen for representing wide industrial networked control systems while adding a WSN dimension based on IEEE 802.15.4 and RPL. The main contribution of this thesis is an experimental study where both the network and controller performance is validated while utilizing commercial o-theshelf sensor platforms. The results from this experimental work include rst the use of established theorems for analyzing control using WSNs. Moreover, the ability of IEEE 802.15.4 and RPL to provide stable communication that is reliable enough for actual industrial control implementation is validated.
38
Wen, Xiaojun. "Distributed MIMO for wireless sensor networks." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5749.
Full textAbstract:
Over the past decade, wireless sensor networks have gained more research attention for their potential applications in healthcare, defense, environmental monitoring, etc. Due to the strict energy limitation in the sensor node, techniques used for energy saving are necessary for this kind of network. MIMO technology is proven to be an effective method of increasing the channel capacity and supporting higher data rate under a fixed power budget and bit-error-rate requirement. So, wireless sensor networks and MIMO technology are combined and investigated in this thesis. The key contributions of this thesis are detailed below. Firstly, the extended total energy consumption equations for different transmission modes in cluster-based wireless sensor networks are derived. The transmitting energy consumption and the circuit energy consumption are taken into account in both intra-cluster and inter-cluster phases respectively. Secondly, a resource allocation framework is proposed for cluster-based cooperative MIMO on consideration of circuit energy. By introducing two adjusting parameters for the transmitting energy and the time slot allocation between intra-cluster and inter-cluster phases, this framework is designed to achieve the maximum data throughput of the whole system whilst maintaining the capacity and outage probability requirement in these two phases respectively. Thirdly, on comparison of various transmission modes in wireless sensor networks, a relatively energy-efficient mode switching framework is proposed for both single-hop and multi-hop transmissions. Based on the destination and the neighboring nodes’ path-loss, the source node can decide which transmission mode, SISO or cooperative MISO, single-hop or multi-hop, should be chosen. Conditions for each mode switching are investigated. The possible existing area of the cooperative nodes and the relaying nodes can be obtained from this framework.
39
Hassani, Bijarbooneh Farshid. "Constraint Programming for Wireless Sensor Networks." Doctoral thesis, Uppsala universitet, Avdelningen för datalogi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-241378.
Full textAbstract:
In recent years, wireless sensor networks (WSNs) have grown rapidly and have had a substantial impact in many applications. A WSN is a network that consists of interconnected autonomous nodes that monitor physical and environmental conditions, such as temperature, humidity, pollution, etc. If required, nodes in a WSN can perform actions to affect the environment. WSNs present an interesting and challenging field of research due to the distributed nature of the network and the limited resources of the nodes. It is necessary for a node in a WSN to be small to enable easy deployment in an environment and consume as little energy as possible to prolong its battery lifetime. There are many challenges in WSNs, such as programming a large number of nodes, designing communication protocols, achieving energy efficiency, respecting limited bandwidth, and operating with limited memory. WSNs are further constrained due to the deployment of the nodes in indoor and outdoor environments and obstacles in the environment. In this dissertation, we study some of the fundamental optimisation problems related to the programming, coverage, mobility, data collection, and data loss of WSNs, modelled as standalone optimisation problems or as optimisation problems integrated with protocol design. Our proposed solution methods come from various fields of research including constraint programming, integer linear programming, heuristic-based algorithms, and data inference techniques.ProFuN
40
Chow, Kit-yee, and 周潔儀. "Angle coverage in wireless sensor networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39341835.
Full text
41
Tan, Haisheng, and 谈海生. "Minimizing interference in wireless sensor networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46419329.
Full text
42
Gezer, Cengiz <1981>. "Wireless Sensor Networks for Monitoring Applications." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4843/.
Full textAbstract:
Wireless Sensor Networks (WSNs) are getting wide-spread attention since they became easily accessible with their low costs. One of the key elements of WSNs is distributed sensing. When the precise location of a signal of interest is unknown across the monitored region, distributing many sensors randomly/uniformly may yield with a better representation of the monitored random process than a traditional sensor deployment. In a typical WSN application the data sensed by nodes is usually sent to one (or more) central device, denoted as sink, which collects the information and can either act as a gateway towards other networks (e.g. Internet), where data can be stored, or be processed in order to command the actuators to perform special tasks. In such a scenario, a dense sensor deployment may create bottlenecks when many nodes competing to access the channel. Even though there are mitigation methods on the channel access, concurrent (parallel) transmissions may occur. In this study, always on the scope of monitoring applications, the involved development progress of two industrial projects with dense sensor deployments (eDIANA Project funded by European Commission and Centrale Adritica Project funded by Coop Italy) and the measurement results coming from several different test-beds evoked the necessity of a mathematical analysis on concurrent transmissions. To the best of our knowledge, in the literature there is no mathematical analysis of concurrent transmission in 2.4 GHz PHY of IEEE 802.15.4. In the thesis, experience stories of eDIANA and Centrale Adriatica Projects and a mathematical analysis of concurrent transmissions starting from O-QPSK chip demodulation to the packet reception rate with several different types of theoretical demodulators, are presented. There is a very good agreement between the measurements so far in the literature and the mathematical analysis.
43
NGUYEN, HONG NHUNG. "INTRUSION DETECTION IN WIRELESS SENSOR NETWORKS." Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3318.
Full textAbstract:
There are several applications that use sensor motes and researchers continue to explore additional applications. For this particular application of detecting the movement of humans through the sensor field, a set of Berkley mica2 motes on TinyOS operating system is used. Different sensors such as pressure, light, and so on can be used to identify the presence of an intruder in the field. In our case, the light sensor is chosen for the detection. When an intruder crosses the monitored environment, the system detects the changes of the light values, and any significant change meaning that a change greater than a pre-defined threshold. This indicates the presence of an intruder. An integrated web cam is used to take snapshot of the intruder and transmit the picture through the network to a remote station. The basic motivation of this thesis is that a sensor web system can be used to monitor and detect any intruder in a specific area from a remote location.M.S.
Department of Electrical and Computer Engineering
Engineering and Computer Science
Computer Engineering
44
Vincent, Patrick J. "Energy conservation in wireless sensor networks." Monterey, California. Naval Postgraduate School, 2007, 2007. http://hdl.handle.net/10945/10228.
Full textAbstract:
This dissertation presents a system-level approach for minimizing the power expended in achieving communication between a ground-based sensor network and an overhead Unmanned Aerial Vehicle (UAV). A subset of sensor nodes, termed a transmit cluster, aggregates data gathered by the network and forms a distributed antenna array, concentrating the radiated transmission into a beam aimed towards the UAV. We present a method for more uniformly distributing the energy burden across the sensor network, specifying the time that should elapse between reassignments of the transmit cluster and the number of hops that should be placed between successive transmit clusters. We analyze the performance of two strategies for reconfiguring the communication burden between the sensor network and the UAV in order to bring the UAV and the sensor network's beam into alignment quickly, while minimizing the energy expenditure. We analyze the optimal number of nodes that should participate in a beamforming process in order to minimize the energy expended by the network, and we provide a framework to analyze the minimum energy expended in a simple beamforming algorithm. Finally, we analyze the probability that an arbitrarily selected sensor node is connected to a specified number of other nodes and we present an algorithm for the formation of near-linear arrays given random placement of nodes.
45
Jobs, Magnus. "Wireless Interface Technologies for Sensor Networks." Doctoral thesis, Uppsala universitet, Fasta tillståndets elektronik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-239400.
Full textAbstract:
The main focus of the work presented in this thesis concerns the development and improvement of Wireless Sensor Networks (WSNs) as well as Wireless Body Area Networks (WBANs). WSN consist of interlinked, wireless devices (nodes) capable of relaying data wirelessly between the nodes. The applications of WSNs are very broad and cover both wireless fitness monitoring systems such as pulse watches or wireless temperature monitoring of buildings, among others. The topics investigated in the work presented within this thesis covers antenna design, wireless propagation environment evaluation and modeling, adaptive antenna control and wireless nodes system design and evaluation. In order to provide an end-user suitable solution for wireless nodes the devices require both small form factor and good performance in order to be competitive on the marked and thus the main part of this thesis focuses on techniques developed and data collected to help achieve these goals. Several different prototype systems have been developed which have been used to measure data by the Swedish Defence Research Agency (FOI), GKN Aerospace Sweden AB, the Swedish Transport Administration. The system developed with GKN Aerospace was used to do real-time test measurements inside a running RM12 jet engine and required a substantial amount of measurements, environmental modeling and system validation in order to properly design a wireless system suitable for the harsh and fast fading environment inside a jet engine. For FOI improvements were made on a wearable wireless body area network initially developed during the authors master thesis work. Refinements included work on new generation wireless nodes, antenna packaging and node-supported diversity techniques. Work and papers regarding the design of different types of antennas suitable for wireless nodes are presented. The primary constraints on the presented antennas are the limited electrical size. The types of antennas developed include electrically small helix antennas manufactured both on stretchable substrates consisting of a PDMS substrate with Galinstan as the liquid metal conductors, screen printed silver ink for helix antennas and conformal dual patch antennas for wireless sensor nodes. Other standard type antennas are included on the wireless sensors as well.
46
Chen, Wei. "Compressive sensing for wireless sensor networks." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607776.
Full text
47
Lin, Min. "Channel modelling for wireless sensor networks." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611656.
Full text
48
Bildea, Ana. "Link Quality in Wireless Sensor Networks." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENM054/document.
Full textAbstract:
L'objectif de la thèse est d'étudier la variation temporelle de la qualité des liens dans les réseaux de capteurs sans fil à grande échelle, de concevoir des estimateurs permettant la différenciation, à court terme et long terme, entre liens de qualité hétérogène. Tout d'abord, nous étudions les caractéristiques de deux paramètres de la couche physique: RSSI (l'indicateur de puissance du signal reçu) et LQI (l'indicateur de la qualité de liaison) sur SensLab, une plateforme expérimentale de réseau de capteurs à grande échelle situé à l'intérieur de bâtiments. Nous observons que le RSSI et le LQI permettent de discriminer des liens de différentes qualités. Ensuite, pour obtenir un estimateur de PRR, nous avons approximé le diagramme de dispersion de la moyenne et de l'écart-type du LQI et RSSI par une fonction Fermi-Dirac. La fonction nous permet de trouver le PRR à partir d'un niveau donné de LQI. Nous avons évalué l'estimateur en calculant le PRR sur des fenêtres de tailles variables et en le comparant aux valeurs obtenues avec l'estimateur. Par ailleurs, nous montrons en utilisant le modèle de Gilbert-Elliot (chaîne de Markov à deux états) que la corrélation des pertes de paquets dépend de la catégorie de lien. Le modèle permet de distinguer avec précision les différentes qualités des liens, en se basant sur les probabilités de transition dérivées de la moyenne et de l'écart-type du LQI. Enfin, nous proposons un modèle de routage basé sur la qualité de lien déduite de la fonction de Fermi-Dirac approximant le PRR et du modèle Markov Gilbert-Elliot à deux états. Notre modèle est capable de distinguer avec précision les différentes catégories de liens ainsi que les liens fortement variablesThe goal of the thesis is to investigate the issues related to the temporal link quality variation in large scale WSN environments, to design energy efficient link quality estimators able to distinguish among links with different quality on a short and a long term. First, we investigate the characteristics of two physical layer metrics: RSSI (Received Signal Strength Indication) and LQI (Link Quality Indication) on SensLAB, an indoor large scale wireless sensor network testbed. We observe that RSSI and LQI have distinct values that can discriminate the quality of links. Second, to obtain an estimator of PRR, we have fitted a Fermi-Dirac function to the scatter diagram of the average and standard variation of LQI and RSSI. The function enables us to find PRR for a given level of LQI. We evaluate the estimator by computing PRR over a varying size window of transmissions and comparing with the estimator. Furthermore, we show using the Gilbert-Elliot two-state Markov model that the correlation of packet losses and successful receptions depend on the link category. The model allows to accurately distinguish among strongly varying intermediate links based on transition probabilities derived from the average and the standard variation of LQI. Finally, we propose a link quality routing model driven from the F-D fitting functions and the Markov model able to discriminate accurately link categories as well as high variable links
49
Kho, Johnsen. "Decentralised control of wireless sensor networks." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/66078/.
Full textAbstract:
Wireless sensor networks are receiving a considerable degree of research interest due to their deployment in an increasing number and variety of applications. However, the efficient management of the limited energy resources of such networks in a way that maximises the information value of the data collected is a significant research challenge. To date, most of these systems have adopted a centralised control mechanism, but from a system's perspective this raises concerns associated with scalability, robustness, and the ability to cope with dynamism. Given this, decentralised approaches are appealing. But, the design of efficient decentralised regimes is challenging as it introduces an additional control issue related to the dynamic interactions between the network's interconnected nodes in the absence of a central coordinator. Within this context, this thesis first concentrates on decentralised approaches to adaptive sampling as a means of focusing a node's energy consumption on obtaining the most important data. Specifically, we develop a principled information metric based upon Fisher information and Gaussian process regression that allows the information content of a node's observations to be expressed. We then use this metric to derive three novel decentralised control algorithms for information-based adaptive sampling which represent a trade-off in computational cost and optimality. These algorithms are evaluated in the context of a deployed sensor network in the domain of flood monitoring. The most computationally efficient of the three is shown to increase the value of information gathered by approximately 83%, 27%, and 8% per day compared to benchmarks that sample in a naive non-adaptive manner, in a uniform non-adaptive manner, and using a state-of-the-art adaptive sampling heuristic (USAC) correspondingly. Moreover, our algorithm collects information whose total value is approximately 75% of the optimal solution (which requires an exponential, and thus impractical, amount of time to compute). The second major line of work then focuses on the adaptive sampling, transmitting, forwarding, and routing actions of each node in order to maximise the information value of the data collected in resource-constrained networks. This adds additional complexity because these actions are inter-related, since each node's energy consumption must be optimally allocated between sampling and transmitting its own data, receiving and forwarding the data of other nodes, and routing any data. Thus, in this setting we develop two optimal decentralised algorithms to solve this distributed constraint optimization problem. The first assumes that the route by which data is forwarded to the base station is fixed (either because the underlying communication network is a tree, or because an arbitrary choice of route has been made) and then calculates the optimal integration of actions that each node should perform. The second deals with flexible routing, and makes optimal decisions regarding both the sampling, transmitting, and forwarding actions that each node should perform, and also the route by which this data should be forwarded to the base station. The two algorithms represent a trade-off in optimality, communication cost, and processing time. In an empirical evaluation on sensor networks (whose underlying communication networks exhibit loops), we show that the algorithm with flexible routing delivers approximately twice the quantity of information to the base station compared to the algorithm with fixed routing. However, this gain comes at a considerable communication and computational cost (increasing both by a factor of 100 times). Thus, while the algorithm with flexible routing is suitable for networks with a small numbers of nodes, it scales poorly, and as the size of the network increases, the algorithm with fixed routing should be favoured.
50
Yan, Chunpeng. "Asynchronous Localization for Wireless Sensor Networks." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1236008270.
Full text