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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.
1

Refinement of an emulator for the physical layer of the wireless communication of sensor networks

Eriksson, Emil January 2014 (has links)
Wireless sensor networks have applications in many different fields and environments, each with their own set of challenges to be overcome. If we can measure and compensate for the properties of the wireless environment at an early stage of the deployment, we will be able to have the sensor network operational in a smaller time frame. This report describes the development of an emulator for wireless sensor network of up to eight 802.15.4 complaint sensor nodes. The FPGA-based emulator has been enhanced with several new features to remove some shortcomings of the existing emulator. The emulator now provides the ability to import previously recorded data representing time varying gains of wireless links, the ability to store the signal data generated by the sensor node for later review, as well as a more intuitive user interface to make the emulator more useful as a research tool. A latency issue that previously prevented the use of any communications protocol depending of transmission acknowledgments has been studied and a solution to the issue is presented. A way of introducing external interference to the emulated system has also been investigated and provides a straightforward way of introducing interference to the system without modifying the existing hardware and software. Most added features have been designed to be easily modified or expanded upon.
2

Semi-Persistent Medium Access Control Protocols for Wireless Sensor Networks

Guennoun, Mouhcine January 2014 (has links)
Wireless Sensor Networks (WSNs) are dense clusters of sensor nodes, made up of small, intelligent, resource-constrained wireless devices that are deployed to monitor a specific phenomenon in a certain field. The sensor nodes can be constrained by limited power supply, memory capacity and/or processing capabilities, which means that the design of WSNs requires all algorithms and protocols to be lightweight and efficient, and use as little power as possible. The Medium Access Control (MAC) protocol in WSNs, defined by the IEEE 802.15.4 standard, employs the Carrier Sense Multiple Access with Collision Avoidance (CSMA-CA) algorithm to control the nodes contending for access to the communication medium. Though the performance of this protocol has been studied extensively, and several improvements to its backoff counter, superframe format and contention-free period (CFP) features have been proposed, very few studies have addressed improving the Clear Channel Assessment (CCA) feature. In this thesis, we study the impact of increasing the value of the contention window beyond the standard value of 2, on the performance of the MAC protocol. We propose a semi-persistent MAC protocol that is a hybrid form of 802.11 and 802.15.4, to achieve a favorable performance that can serve a broad range of applications over the IEEE 802.15.4-based WSNs. We build an analytical model of the proposed protocol based on Markov chain modelling and derive the analytical expressions of the performance metrics, which we then validate against the simulation result sets generated by our in-house built simulation framework. We prove analytically that the probability of collision of the semi-persistent MAC is lower than that of the standard protocol. Based on our theoretical and simulated models, we show that incorporating the semi-persistent feature into existing MAC protocols leads to significant improvement of the performance metrics, including the probability of collision, throughput, energy consumption, transmission delay and reliability, particularly for networks with a large number of sensor nodes.
3

T4 Technology Evaluation : Technology Evaluation for Telematics for Totally Transparent Transports

Wallner, Michael, Westlund, Johan, Mansouri, Amir January 2006 (has links)
<p>This thesis is about the design of a Telematics for Totally Transparent Transports System </p><p>(T4 System). T4 System combines Wireless Sensor Network (WSN) technology with </p><p>ordinary fleet management systems to monitor and track cargo on a global scale. This </p><p>means that the cargo itself and not the vehicle transporting the cargo will be observed. </p><p>This has the advantage that a change in the transportation method can be made without </p><p>interrupting the tracking device. T4 System is not only a simple tracking device which only </p><p>monitors the transportation conditions; it also interacts with the chain of transportation </p><p>in case of a faulty situation, to provide the possibility to correct the error. </p><p>To keep the transportation process as transparent as possible T4 System uses a two way </p><p>communication and control strategy which allows, e.g. the customer, to check and/or </p><p>update the transport conditions or measurement parameters, respectively, in run-time, </p><p>when the situation demands it.</p>
4

A Middleware of Wireless sensor networks for Home healthcare monitoring application : Design and implementation based on multiple module of data acquisition

Tang, Jun January 2013 (has links)
With the continued increases in the global population, a serious problem will occur in relation to an ageing population. The reason for this is that a significant number of elderly people may suffer from serial chronic diseases making it difficult for them to live independently and thus they pose a significant economic burden for both themselves and for their government. In order to solve this problem, more and more E-healthcare applications are being designed. In addition, a wide range of medical sensors exist, which can monitor almost all the important physiological parameters of the human body. However, different sensors may use different communication protocols, data units and formats. Additionally, the elderly may use more than one E-healthcare application at the same time and this can lead to problems if there is more than one data source. The project “A Middleware of Wireless sensor networks for Home healthcare monitoring application” is designed to solve these problems.  The focus of this report is on the design and implementation based on multiple modules of data acquisition. There are four data acquisition modules which include the ZigBee module, 6LowPAN module, Wi-Fi module and a Bluetooth module. Thus, multiple data acquisition module middleware supports the sensor by means of ZigBee, 6LowPAN, Wi-Fi and Bluetooth. The tasks of the middleware are to collect packets from sensors, perform data processing and mapping and then displaying as real-time data and finally transmitting the data to the remote server.
5

Wireless Sensor Network Group Connectivity

Sajadian, Samar, Ibrahim, Alia January 2010 (has links)
The importance of monitoring physical and environmental conditions increases day by day and, therefore, so is the necessity of having a reliable wireless sensor network (WSN). The need to overcome challenges in WSN deployment and operation arises due to WSN's nature and characteristics such as possible nodes' mobility, limited radio and processing power, available storage and physical effects of the environment (particularly harsh environments) and balancing energy consumption has motivated us to investigate solutions to those problems. By studying related work, it was possible to observe that techniques such as the use of a good link estimator and the deployment of a suitable topology are essential features for a WSN. The core idea is to capture link connectivity dynamically and use it on routing decisions to gain reliability and estimate the whole network connectivity. The three main steps for deployment of a reliable WSN are the following: -         Link estimator -         Routing and neighbor information -         Suitable routing algorithms In addition, self-organization is an important capability that WSNs need to present. They should be reliable, scalable and energy efficient during the network lifetime and self-organization plays a key role in this context. Summing up all these aspects, it comes to the point that reliable connectivity is an important characteristic of a WSN. The goal of this work is to contribute with the research in the subject by means of implementing a suitable topology management and evaluating the network connectivity by the means of quantitative metric for the network as whole. Practical experiments results are presented and discussed.
6

T4 Technology Evaluation : Technology Evaluation for Telematics for Totally Transparent Transports

Wallner, Michael, Westlund, Johan, Mansouri, Amir January 2006 (has links)
This thesis is about the design of a Telematics for Totally Transparent Transports System (T4 System). T4 System combines Wireless Sensor Network (WSN) technology with ordinary fleet management systems to monitor and track cargo on a global scale. This means that the cargo itself and not the vehicle transporting the cargo will be observed. This has the advantage that a change in the transportation method can be made without interrupting the tracking device. T4 System is not only a simple tracking device which only monitors the transportation conditions; it also interacts with the chain of transportation in case of a faulty situation, to provide the possibility to correct the error. To keep the transportation process as transparent as possible T4 System uses a two way communication and control strategy which allows, e.g. the customer, to check and/or update the transport conditions or measurement parameters, respectively, in run-time, when the situation demands it.
7

An indoor localization system based on wireless sensor networks

Zhou, Bin 14 January 2016 (has links)
Although the Global Position System (GPS) can help to navigate around the world, it cannot provide useful information in an indoor environment. I developed an indoor localization system using wireless sensor networks (WSNs). This system has two goals: (1) to make a system that runs for long duration without changing or charging batteries, and (2) to obtain more accurate position estimates of the target nodes using received signal strength indicator (RSSI) values than other localization systems using different localization algorithms. I chose ANT radio due to its lower power consumption. I applied a fingerprinting-based algorithm and used the parameters of the closest point to the estimated target node to calculate the final position of a target node. A local weighted k-Nearest Neighbour algorithm was proposed to estimate the position of a mobile node. I compared my system to other indoor localization systems to assess its performance. / February 2016
8

Design of the Communication and Control Systems for Robotic Cleaning and Inspection of Solar Power Plants

Tang, Qianjun 11 June 2021 (has links)
The aim of this research is to design the communications monitoring and control functionalities of an energy-efficient, scalable system, capable of supporting robotic cleaning and fault detection of photovoltaic panels, deployed in solar electric power generation plants. The communication functionality is implemented by using a wireless sensor network (WSN) deployed over the photovoltaic energy production plant’s area. The network is designed to support the communication needs of static-sensing nodes as well as moving robotic units. It transports sensing data and commands between end units and the monitoring and control entity of the electric energy generation plant. Having robotic units replace humans in the cleaning and inspection tasks not only reduces the operational cost of the plant, but also results in increased energy production. Several innovations were necessary to achieve our objective, which are presented in this dissertation. A working prototype of the cleaning robotic system was built and tested in a solar power plant for a duration of 6 month. The prototyping was done in collaboration of Tipot technology.
9

Une solution tolérante aux délais pour des applications de localisation et de traçabilité a posteriori en milieux confinés / A tolerant solution to deadlines for tracking and traceability applications post in confined spaces

Baouche, Mohamed Chakib 12 July 2012 (has links)
Cette thèse porte sur l’exploitation d’une population nomade afin de colporter des informations dites ‘atomiques’ de rencontres entre entités fixes ou mobiles pour des applications diverses basées sur la localisation et la traçabilité. Répondre à ces besoins en milieux confinés s’avère un défi, que ce soit dans un contexte industriel, médical ou social. Parmi les solutions existantes, le système GPS (Global Positioning System) offre des résultats encourageants lorsqu’il s’agit de connaître une position en extérieur. Cette solution n’est plus utilisable en intérieur tel que dans une mine par exemple, en raison des caractéristiques du signal fortement perturbées dans ce type de milieu. Le fil directeur de ce travail consiste à proposer un modèle utilisant la technologie des réseaux de capteurs sans fil afin de modéliser et de trouver des solutions à des problématiques allant de la localisation en milieux confinés au suivi et à la reconstitution de trajectoires d’entités mobiles. Les solutions proposées dans cette thématique doivent être tolérantes aux délais. Après avoir présenté les constituants de notre modèle générique de colportage, une instanciation de ce modèle a permis de nous pencher sur un cas de localisation et de traçabilité dans un espace confiné. Les résultats de simulation et d’expérimentation ont montré l’impact de notre mécanisme de colportage sur la qualité de l’information recensée concernant les déplacements et les rencontres des entités mobiles. Outre la proposition d’un modèle générique, la contribution de cette thèse comporte des mécanismes de colportage (et de filtrage) de l’information par des entités mobiles contraintes en taille mémoire. / This thesis focuses on the exploitation of a nomadic population to pass around information called contact event which represents the recording of a meeting between fixed or mobile entities for localization and tracking applications. Addressing these needs in confined environments is a challenge, whether in an industrial, medical or social context. Among the existing solutions, the GPS (Global Positioning System) provides encouraging results for outdoor localization. However, this solution is not operational in confined environments such as mines, due to the signal characteristics highly disturbed in this type of environment. The guiding principle of this work is to propose a model using the technology of wireless sensor networks for modeling and finding solutions for localization and tracking mobile nodes in confined areas. The new approach proposed in this thesis is inspired by the principle of ‘store-carry-forward’ of Delay-Tolerant-Network (DTN). After presenting the components of our generic model, an instantiation of this model has allowed us to address a localization and tracking case in a confined area. The simulation and experimentation results show the impact of our filtering mechanism on the quality of the knowledge collected concerning the movements and meetings of the mobile nodes.
10

A Novel Scalable Key Management Protocol for Wireless Sensor Networks

Rahman, Musfiq 26 March 2013 (has links)
Wireless Sensor Networks (WSNs) are ad-hoc networks consisting of tiny battery- operated wireless sensors. The sensor nodes are lightweight in terms of memory, computation, energy and communication. These networks are usually deployed in unsecured, open, and harsh environments, where it is difficult for humans to perform continuous monitoring. Consequently, it is very crucial to provide security mecha- nisms for authenticating data among sensor nodes. Key management is a pre-requisite for any security mechanism. Efficient distribution and management of keys in WSNs is a challenging task. Many standard key establishment techniques have been pro- posed using symmetric cryptosystems. Unfortunately, these systems often fail to pro- vide a good trade-off between memory and security and since WSNs are lightweight in nature, these cryptosystems are not feasible. On the other hand, public key in- frastructure (PKI) is infeasible in WSNs because of its continuous requirement of a trusted third party and heavy computational demands for certificate verification. Pairing-Based Cryptography (PBC) has paved the way for how parties can agree on keys without any interaction. It has relaxed the requirement of expensive certificate verification on PKI systems. In this thesis, we propose a new hybrid identity-based non-interactive key management protocol for WSNs, which leverages the benefits of both symmetric key based cryptosystems and pairing-based cryptosystems. The pro- posed protocol is scalable, suits many applications and can be deployed in multiple types of networks without modifications. We also provide mechanisms for key refresh when the network topology changes. A security analysis is presented to prove that the scheme is resilient to many types of attacks. To validate our scheme, we have implemented it on Crossbow TelosB motes running TinyOS and analyzed the perfor- mance in terms of memory, communication, computation and energy consumption. The results indicate that our scheme can be deployed efficiently to provide high level of security in a large-scale network without increasing memory, communication and energy overheads.

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