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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Data Security in Unattended Wireless Sensor Networks

Vepanjeri Lokanadha Reddy, Sasi Kiran January 2013 (has links)
In traditional Wireless Sensor network's (WSN's), the sink is the only unconditionally trusted authority. If the sink is not connected to the nodes for a period of time then the network is considered as unattended. In Unattended Wireless Sensor Network (UWSN), a trusted mobile sink visits each node periodically to collect data. This network differs from the traditional multi hop wireless sensor networks where the nodes close to the sink deplete their power earlier than the other nodes. An UWSN can prolong the life time of the network by saving the battery of the nodes and also it can be deployed in environments where it is not practical for the sink to be online all the time. Saving data in the memory of the nodes for a long time causes security problems due to the lack of tamper-resistant hardware. Data collected by the nodes has to be secured until the next visit of the sink. Securing the data from an adversary in UWSN is a challenging task. We present two non-cryptographic algorithms (DS-PADV and DS-RADV) to ensure data survivability in mobile UWSN. The DS-PADV protects against proactive adversary which compromises nodes before identifying its target. DS-RADV makes the network secure against reactive adversary which compromises nodes after identifying the target. We also propose a data authentication scheme against a mobile adversary trying to modify the data. The proposed data authentication scheme uses inexpensive cryptographic primitives and few message exchanges. The proposed solutions are analyzed both mathematically and using simulations proving that the proposed solutions are better than the previous ones in terms of security and communication overhead.
172

Localized Ant Colony of Robots for Redeployment in Wireless Sensor Networks

Wang, Yuan January 2014 (has links)
Sensor failures or oversupply in wireless sensor networks (WSNs), especially initial random deployment, create both spare sensors (whose area is fully covered by other sensors) and sensing holes. We envision a team of robots to relocate sensors and improve their area coverage. Existing algorithms, including centralized ones and the only localized G-R3S2, move only spare sensors and have limited improvement because non-spare sensors, with area coverage mostly overlapped by neighbour sensors, are not moved, and additional sensors are deployed to fill existing holes. We propose a localized algorithm, called Localized Ant-based Sensor Relocation Algorithm with Greedy Walk (LASR-G), where each robot may carry at most one sensor and makes decision that depends only on locally detected information. In LASR-G, each robot calculates corresponding pickup or dropping probability, and relocates sensor with currently low coverage contribution to another location where sensing hole would be significantly reduced. The basic algorithm optimizes only area coverage, while modified algorithm includes also the cost of robot movement. We compare LASR-G with G-R3S2, and examine both single robot and multi robots scenarios. The simulation results show the advantages of LASR-G over G-R3S2.
173

Distributed spatial analysis in wireless sensor networks

Jabeen, Farhana January 2011 (has links)
Wireless sensor networks (WSNs) allow us to instrument the physical world in novel ways, providing detailed insight that has not been possible hitherto. Since WSNs provide an interface to the physical world, each sensor node has a location in physical space, thereby enabling us to associate spatial properties with data. Since WSNs can perform periodic sensing tasks, we can also associate temporal markers with data. In the environmental sciences, in particular, WSNs are on the way to becoming an important tool for the modelling of spatially and temporally extended physical phenomena. However, support for high-level and expressive spatial-analytic tasks that can be executed inside WSNs is still incipient. By spatial analysis we mean the ability to explore relationships between spatially-referenced entities (e.g., a vineyard, or a weather front) and to derive representations grounded on such relationships (e.g., the geometrical extent of that part of a vineyard that is covered by mist as the intersection of the geometries that characterize the vineyard and the weather front, respectively). The motivation for this endeavour stems primarily from applications where important decisions hinge on the detection of an event of interest (e.g., the presence, and spatio-temporal progression, of mist over a cultivated field may trigger a particular action) that can be characterized by an event-defining predicate (e.g., humidity greater than 98 and temperature less than 10). At present, in-network spatial analysis in WSN is not catered for by a comprehensive, expressive, well-founded framework. While there has been work on WSN event boundary detection and, in particular, on detecting topological change of WSN-represented spatial entities, this work has tended to be comparatively narrow in scope and aims. The contributions made in this research are constrained to WSNs where every node is tethered to one location in physical space. The research contributions reported here include (a) the definition of a framework for representing geometries; (b) the detailed characterization of an algebra of spatial operators closely inspired, in its scope and structure, by the Schneider-Guting ROSE algebra (i.e., one that is based on a discrete underlying geometry) over the geometries representable by the framework above; (c) distributed in-network algorithms for the operations in the spatial algebra over the representable geometries, thereby enabling (i) new geometries to be derived from induced and asserted ones, and (ii)topological relationships between geometries to be identified; (d) an algorithmic strategy for the evaluation of complex algebraic expressions that is divided into logically-cohesive components; (e) the development of a task processing system that each node is equipped with, thereby with allowing users to evaluate tasks on nodes; and (f) an empirical performance study of the resulting system.
174

Analisador de redes wirelesshart

Lorençato, Alexandre de Andrade January 2013 (has links)
A segurança da informação, a diversidade de rotas entre os dispositivos da rede, o acesso ao meio de modo determinístico e isento de colisões e a mudança de canal frequente tornam a comunicação no protocolo WirelessHART robusta e confiável para utilização em meio industrial. Entretanto, para adoção crescente dessa tecnologia, é necessário que os fabricantes de sensores e atuadores industriais desenvolvam dispositivos WirelessHART. Disto surge a necessidade de criação de ferramentas capazes de auxiliar o desenvolvimento e depuração destes novos dispositivos de rede. O Analisador de rede WirelessHART é, sem dúvida, uma delas. Diversas abordagens são propostas para a análise de redes WirelessHART. Entretanto, em todas elas a utilização de um microcomputador como elemento do sistema inviabiliza sua utilização em campo. A presença de cabos, armazenamento local dos dados e exigência de baterias são alguns dos aspectos relevantes que devem ser levados em consideração quando o sistema precisa ser utilizado em campo. O presente trabalho propõe alternativas aos sistemas de análise de redes atuais apresentando duas propostas conceitualmente diferentes mas que cumprem os requisitos básicos para sua utilização em campo. Uma destas abordagens, baseada na proposta de integração entre um dispositivo de campo e o método inovador de captura de mensagens utilizando apenas um transceptor, é implementado como prova do conceito. / WirelessHART is a robust and reliable protocol for industrial environment usage because of its secure mechanism, the ability of programming several communication routes between network devices, and deterministic, free of collisions channel hopping medium access controller. However, in order to increase the adoption of this technology, it is necessary to increase the amount of WirelessHART manufacturers to develop industrial sensors and actuators devices. This leads to the necessity of create tools that will assist the development and debugging of new network compliant devices. The WirelessHART network analyzer is undoubtedly one of these tools. Various approaches are being proposed for the analysis of WirelessHART networks. However, all of them make use of a microcomputer as an element of the whole system and this difficults their use in real field applications. The presence of wires, lack of local data storage and other aspects such as batteries limitations must be considered when the users intend to use analysis systems in field. This work proposes alternatives to current analysis networks systems by presenting two conceptually different proposals that meet the basic requirements for the use in the field. One of them is based on the proposed integration between a field device and an innovative method of capturing messages using only one transceiver, which is implemented as proof of concept.
175

WSN Routing Schedule Based on Energy-aware Adaptation

Peng, Tingqing January 2020 (has links)
In view of the problem of uneven load distribution and energy consumption among nodes in a multi-hop wireless sensor network, this research constructs the routing schedule problem as a MOP (Multi-objective Optimization Problem), and proposed an energy-aware routing optimization scheme RDSEGA based on multi-objective optimization. In this scheme, in order to avoid the searching space explosion problem caused by the increase of nodes, KSP Yen's algorithm was applied to prune the searching space, and the candidate paths selected after pruning are recoded based on priority. Then adopted the improved strengthen elitist genetic algorithm to get the entire network routing optimization scheme with the best energy efficiency. At the same time, in view of the problem of routing discontinuity in the process of path crossover and mutation, new crossover and mutation method was proposed that based on the gene fragments connected by the adjacent node or the same node to maximize the effectiveness of the evolution result. The experimental results prove that the scheme reduced the energy consumption of nodes in the network, the load between nodes becomes more balanced, and the working time of the network has been prolonged nearly 40% after the optimization. This brings convenience to practical applications, especially for those that are inconvenient to replace nodes.
176

A Multi-layered Routing Technique for Sensing Train Integrity and Composition

Pulugurtha, Satya Venkata Sidhi Vinayak, Atragadda, Kishore Kumar January 2020 (has links)
This thesis deals with an approach to monitor the integrity and composition of cargo wagons withthe help of Wireless Sensor Network (WSN). The WSN is to be fully automated that does notneed any human intervention for gathering information about the composition and integrity ofcargo trains, which are the most necessary factors for Cargo Logistics. The nodes are deployed inevery wagon along with the master node in the main locomotive. The master node in thelocomotive gets the information from the slave nodes placed in the cargo wagons in successivesessions. If there are any unexpected changes in the composition of the wagon, theacknowledgments to the locomotive will be terminated. This approach mainly focuses ondesigning energy-efficient as well as cost-efficient WSN. The designed WSN can accommodateto changes, which are caused by external conditions. The designed approach is also scalable. TheWSN is designed with the usage of Zigbee mesh protocol with Arduino Microcontroller as thebrain of the system that is validated and verified in the indoor, imitating the railway environment.
177

Development of a Wireless Sensor Network System for Occupancy Monitoring

Onoriose, Ovie 12 1900 (has links)
The ways that people use libraries have changed drastically over the past few decades. Proliferation of computers and the internet have led to the purpose of libraries expanding from being only places where information is stored, to spaces where people teach, learn, create, and collaborate. Due to this, the ways that people occupy the space in a library have also changed. To keep up with these changes and improve patron experience, institutions collect data to determine how their spaces are being used. This thesis involves the development a system that collects, stores, and analyzes data relevant to occupancy to learn how a space is being utilized. Data is collected from a temperature and humidity sensor, passive Infrared sensor, and an Infrared thermal sensor array to observe people as they occupy and move through a space. Algorithms were developed to analyze the collected sensor data to determine how many people are occupying a space or the directions that people are moving through a space. The algorithms demonstrate the ability to track multiple people moving through a space as well as count the number of people in a space with an RMSE of roughly 0.39 people.
178

Webové rozhraní pro monitoring senzorového pole / Web interface for sensor network monitoring

Vajsar, Pavel January 2010 (has links)
The aim of this work is to design and create an application that will allow monitoring of wireless sensor networks. The basis of the project is to design a database that is capable of storing data acquired from wireless sensor networks. The main requirement for the design is versatility, which flows from the requirement to use the database for broad range of applications implementing wireless sensor networks. The application itself is designed to be the most versatile and modular, which means that modules provide specific monitoring services. The application is able to monitor the real wireless sensor network through designed and implemented connector. For implementation J2EE (server side) and Adobe Flex/Air (client side) technologies are used.
179

Návrh senzorové sítě pro monitoring osob a věcí v budově / Proposal of wireless sensor network for indoor monitoring of people and objects

Záděra, Zdeněk January 2011 (has links)
This thesis describes the design of wireless sensor network (WSN) for monitoring of people and objects in a building. The work deals with issues of localization and tracking in sensor networks and algorithm implementation to sensor nodes. It also contains a description of the aplication requirements. These requirements form the basis for the proposal. The hardware part of the network consists of sensor nodes IRIS from Crossbow company. The work describes the properties of these nodes. Next part deals with of propagation model and design of the localization algorithm. The paper also describes the communication in the network. The thesis also includes a practical realization of the proposed network, the localization system and its testing. In the work is included a CD with the building schematic in AutoCAD and with source code of created applications.
180

Webové rozhraní pro komunikaci s uzly bezdrátové senzorové sítě / Web user interface for communicating with the wireless sensor nodes

Černocký, Petr January 2011 (has links)
The aim of this master's thesis is to design and create web application that allows analysing and monitoring wireless sensor networks. The main function is to load plan of given area and shown position of the sensor network nodes. These nodes allow user to set which measured phenomenon will be display on them. The measured values can be loaded directly from sensor nodes or from database server. Visualized values for user defined time period can be displayed in the implemented graph. The application itself is programmed in JavaFX language and follows the rules of REST architecture. For easier communication with database server application uses the MyBatis framework.

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