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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.
191

ZigBee 無線感測網路應用程式介面設計與實作 / Design and implementation of a ZigBee sensor network application programming interface

陳文杰, Chen, Wen Chieh Unknown Date (has links)
ZigBee在無線網路技術中,乃屬較新之無線傳輸技術, 其特色為低電耗、可控制大量感測裝置、反應時間短、建置成本低廉等。其遵循IEEE802.15.4標準與ZigBee通訊協定標準,目前已有ZigBee Alliance制定相關標準與推動此技術,而控制晶片以德州儀器(TI)為主要制訂及生產供應商。ZigBee網路支援星狀、樹狀、網狀三種網路架構,其裝置角色有Coordinator、Router, End Device三種。目前主要應用有軍事為健康、環境、健康、家庭及商業等方面。應用上除了利用韌體方式實作裝置對裝置的控制,有些應用尚需借由應用程式才能達成。本論文主要強調利用API讓應用程式控制裝置取得感測資料更為容易,其亦可解決同時回報或監測所有裝置之問題。 目前整個API針對裝置晶片控制指令集定義成一類別,此部份可依不同晶片版本做類別庫切換。另外,定義如何與Serial Port溝通,以及傳輸指令或資料時是否符合ZigBee通訊協定要求之判斷。基於以上類別庫之定義,最後定義DeviceManager類別,當作管理裝置之物件,而該類別中,為讓開發者更容易操作,將各類感測讀取動作,封裝成方法(Method)定義之。 基於已定義完成之API,為讓開發者更了解ZigBee運作,列出主要七種運作流程, 並說明讀取感測資料之程式控制方式,以及如何擴充新類型感測裝置之方法(Method),而這些流程與控制方式透過整個網路管理軟體的實作更能體現之。 / ZigBee is a cutting-edge wireless transmission technology, characterized by consuming little power, controlling multiple sensor devices, reacting quickly, and needing low implementing costs, etc. This technology follows IEEE802.15.4 and ZigBee communications protocol. ZigBee-based sensors are widely used in many domains, such as military, natural environments, health, family, and business. Many existing applications of ZigBee use firmware controlling devices, but higher-level application programs are still required to realize some applications. This thesis focuses on how to use Application Programming Interface (API) for controlling devices to collect sensor data and how to solve the problems on reporting data and monitoring all the devices used. In particular, we define the DeviceManager class that controls the set of instructions of device chips and communicates with serial ports as well as determines whether transfer instructions and data by following the standard of ZigBee protocol. For developers' convenience, we further encapsulate different sensor-reading actions into method. Based on the above API definitions, we list seven implementation flows for developers to understand the implementation of ZigBee. This thesis also describes how to use programming control to read sensor data and how to expand new sensor devices. These flows and control methods can be easily achieved by network management software.
192

Réseaux Ad Hoc : Performance, Dimensionnement, Gestion Automatisée et Intégration dans l'Internet

Herberg, Ulrich 20 May 2011 (has links) (PDF)
Le présent rapport fournit plusieurs extensions des protocoles de réseau ad hoc et leurs évaluations, qui permettent d'augmenter la performance, de dimensionner la taille des réseaux et d'intégrer les réseaux ad hoc dans l'Internet : Premièrement, ce rapport présente plusieurs outils de logiciel qui permettent d'étudier des protocoles de routage sans modifications, implémentés en Java, dans le simulator de réseaux NS2. Deuxièmement, ce rapport fournit une discussion architecturale des réseaux ad hoc, qui explique les problèmes de la configuration automatique des adresses IP (nommé autoconfiguration) des routeurs ad hoc. Ensuite, le rapport présente un modèle architectural pour des réseaux ad hoc qui est compatible avec l'Internet. Un protocole d'autoconfiguration, basé sur le modèle architectural proposé, est spécifié, et ses propriétés sont formellement vérifiées au moyen de Model Checking. Troisièmement, plusieurs extensions du protocole de routage des réseaux ad hoc OLSRv2 sont présentées : La performance du protocole est augmentée d'ordre de grandeur en utilisant un algorithme dynamique pour calculer les plus courts chemins. Une autre optimisation proposée est un framework basé sur SNMP pour gérer et contrôler des objets liés à la performance sur des routeurs tournant OLSRv2. Une extension d'OLSRv2 est présentée dans laquelle des paquets sont retransmis ultérieurement lorsque les destinations sont indisponibles temporairement, au lieu de les rejeter. Cette extension mène à un taux de remis considérablement plus élevé que OLSRv2 par défaut dans certains scenarios. Ce rapport présente alors une analyse des menaces de sécurité pour OLSRv2, suivie par la spécification d'un mécanisme de contrôle d'accès pour OLSRv2, qui empêche nombre de ces attaques. Quatrièmement, ce rapport explore le dimensionnement des réseaux de capteurs sans fil, et évalue un protocole de routage des réseaux de capteurs, nommé RPL, spécifié par l'IETF en 2011. En outre, étant donné que RPL ne contient pas de mécanisme de broadcast efficace, plusieurs mécanismes de broadcast optimisés dans RPL sont présentés et comparés.
193

Implementation and performance analysis of star-based mesh network

Haq, Muhammad January 2011 (has links)
The goal of the thesis is to design the star-based mesh topology by introducing multiple pan-coordinators (hub/switches) under a multipath-fading environment and to improve the data transaction rate of a network which usually gets worst when there is a single pan-coordinator for synchronization of devices in conventional mesh topology; also reduce the hop-count as least as possible. Most of the work has been done on NS-2 network simulator; therefore the research model which has been used here is a simulation model. Altogether 3 simulations have been done. The first scenario is done on a simplest mesh network with a single coordinator and a radio propagation model which has been used is two-ray ground reflection model. The second scenario simulation is similar to the first scenario but in-order to provide multi-path signal fading and highly congested environment the propagation model which has been used this time is shadowing model. The final simulation which has been done is of multiple-star based mesh topology it also uses the similar radio propagation model which has been defined for second scenario. An intensive performance measurement of all the three simulations has been done in terms of transactions made per-second, packet drop rate along with an analysis of packet drop. An hop-count is also measured between star and mesh topology. For multiple star based mesh topology it can be assumed if multiple stars with a routing capability can be used then nodes in a network will be synchronized or re-synchronized with least number of hops in the congested network with a near-by pan-coordinator (hub/switch). One of the major applications of this topology can be automobile manufacturing industry where alot of machines are installed in a congested network and monitoring of every area is mandatory for swift production.
194

Identification And Localization On A Wireless Magnetic Sensor Network

Baghaee, Sajjad 01 June 2012 (has links) (PDF)
This study focused on using magnetic sensors for localization and identification of targets with a wireless sensor network (WSN). A wireless sensor network with MICAz motes was set up utilizing a centralized tree-based system. The MTS310, which is equipped with a 2-axis magnetic sensor was used as the sensor board on MICAz motes. The use of magnetic sensors in wireless sensor networks is a topic that has gained limited attention in comparison to that of other sensors. Research has generally focused on the detection of large ferromagnetic targets (e.g., cars and airplanes). Moreover, the changes in the magnetic field intensity measured by the sensor have been used to obtain simple information, such as target direction or whether or not the target has passed a certain point. This work aims at understanding the sensing limitations of magnetic sensors by considering small-scale targets moving within a 30 cm radius. Four heavy iron bars were used as test targets in this study. Target detection, identification and sequential localization were accomplished using the Minimum Euclidean Distance (MED) method. The results show the accuracy of this method for this job. Different forms of sensor sensing region discretization were considered. Target identification was done on the boundaries of sensing regions. Different gateways were selected as entrance point for identification point and the results of them were compared with each other. An online ILS system was implemented and continuous movements of the ferromagnetic objects were monitored. The undesirable factors which affect the measurements were discussed and techniques to reduce or eliminate faulty measurements are presented. A magnetic sensor orientation detector and set/reset strap have been designed and fabricated. Orthogonal Matching Pursuit (OMP) algorithm was proposed for multiple sensors multiple target case in ILS systems as a future work. This study can then be used to design energy-efficient, intelligent magnetic sensor networks
195

Design of vibrational and solar energy harvesting systems for powering wireless sensor networks in bridge structural health monitoring applications

Adams, Jacob Allan 03 February 2015 (has links)
Structural health monitoring systems provide a promising route to real-time data for analyzing the current state of large structures. In the wake of two high-profile bridge collapses due to an aging highway infrastructure, the interest in implementing such systems into fracture-critical and structurally deficient bridges is greater now than at any point in history. Traditionally, these technologies have not been cost-effective as bridges lack existing wiring architecture and the addition of this is cost prohibitive. Modern wireless sensor networks (WSN) now present a viable alternative to traditional networking; however, these systems must incorporate localized power sources capable of decade-long operation with minimal maintenance. To this end, this thesis explores the development of two energy harvesting systems capable of long-term bridge deployment with minimal maintenance. First, an electromagnetic, linear, vibrational energy harvester is explored that utilizes the excitations from passing traffic to induce motion in a translating permanent magnet mass. This motion is then converted to electrical energy using Faraday’s law of induction. This thesis presents a review of vibrational energy harvesting literature before detailing the process of designing, simulating, prototyping, and testing a selected design. Included is an analysis of the effects of frequency, excitation amplitude, load, and damping on the power production potential of the harvester. Second, a solar energy harvester using photovoltaic (PV) panels is explored for powering the critical gateway component of the WSN responsible for data aggregation. As solar energy harvesting is a more mature technology, this thesis focuses on the methodologies for properly sizing a solar harvesting system and experimentally validating the selected design. Fabrication of the prototype system was completed and field testing was performed in Austin, TX. The results validate the selected system’s ability to power the necessary 14 W DC load with a 0° panel azimuth angle (facing direct south) and 45° tilt. / text
196

Secure collection and data management system for WSNs

Drira, Wassim 10 December 2012 (has links) (PDF)
Nowadays, each user or organization is already connected to a large number of sensor nodes which generate a substantial amount of data, making their management not an obvious issue. In addition, these data can be confidential. For these reasons, developing a secure system managing the data from heterogeneous sensor nodes is a real need. In the first part, we developed a composite-based middleware for wireless sensor networks to communicate with the physical sensors for storing, processing, indexing, analyzing and generating alerts on those sensors data. Each composite is connected to a physical node or used to aggregate data from different composites. Each physical node communicating with the middleware is setup as a composite. The middleware has been used in the context of the European project Mobesens in order to manage data from a sensor network for monitoring water quality. In the second part of the thesis, we proposed a new hybrid authentication and key establishment scheme between senor nodes (SN), gateways (MN) and the middleware (SS). It is based on two protocols. The first protocol intent is the mutual authentication between SS and MN, on providing an asymmetric pair of keys for MN, and on establishing a pairwise key between them. The second protocol aims at authenticating them, and establishing a group key and pairwise keys between SN and the two others. The middleware has been generalized in the third part in order to provide a private space for multi-organization or -user to manage his sensors data using cloud computing. Next, we expanded the composite with gadgets to share securely sensor data in order to provide a secure social sensor network
197

Distributed Contention-Free Access for Multi-hop IEEE 802.15.4 Wireless Sensor Networks

Khayyat, Ahmad 26 October 2007 (has links)
The IEEE 802.15.4 standard is a low-power, low-rate MAC/PHY standard that meets most of the stringent requirements of single-hop wireless sensor networks. Sensor networks with nodal populations comprised of thousands of devices have been envisioned in conjunction with environmental, vehicular, and military applications, to mention a few. However, such large sensor network deployments necessitate multi-hop support as well as low power consumption. In light of the standard's extremely limited joint support of the two aforementioned attributes, this thesis presents two essential contributions. First, a framework is proposed to implement a new IEEE 802.15.4 operating mode, namely the synchronized peer-to-peer mode. This mode is designed to enable the standard's low-power features in peer-to-peer multi-hop-ready topologies. The second contribution is a distributed Guaranteed Time Slot (dGTS ) management scheme designed to function in the newly devised network mode. This protocol provides reliable contention-free access in peer-to-peer topologies in a completely distributed manner. Assuming optimal routing, our simulation experiments reveal perfect delivery ratios as long as the traffic load does not reach or surpass its saturation threshold. dGTS sustains at least twice the delivery ratio of contention access under sub-optimal dynamic routing. Moreover, the dGTS scheme exhibits minimum power consumption by eliminating the retransmissions attributed to contention, which in turn reduces the number of transmissions to a minimum. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2007-10-25 14:55:36.811
198

Conception et évaluation de performances d'un réseau de capteurs sans fil hétérogène pour une application domotique

Zatout, Youssouf 07 July 2011 (has links) (PDF)
Les progrès technologiques permettent aujourd'hui l'intégration à bas coût d'objets multi-capteurs hétérogènes communicants sans fil notamment pour la surveillance dans les environnements considérés à risques ou non accessibles. Le but de ces travaux de thèse est de contribuer à la sécurisation des personnes et de leur environnement de vie par la mise en réseau de dispositifs multi-capteurs de mesures sans fil. Ceux-ci doivent être spécifiés et configurés pour rendre par exemple l'environnement qu'ils surveillent intelligent et sécurisé. Le travail effectué porte sur la conception et le prototypage réel d'un réseau composé de dispositifs hétérogènes autonomes en énergie. Nos contributions comportent trois volets essentiels : Le premier volet concerne la conception d'un modèle de réseau ambiant adapté : nous avons proposé un modèle qui repose sur une architecture multi-niveaux caractérisée par des nœuds hétérogènes dont le captage (détection), le traitement et le stockage des données sont distribués par niveau. Cette architecture hiérarchique offre plusieurs avantages par rapport aux architectures linéaires classiques en termes d'évolutivité, de faible coût, de meilleure couverture, de hautes fonctionnalités et de fiabilité. Nous avons défini le comportement adapté pour chaque nœud dans le modèle et montré l'avantage de la solution par la simulation. Le deuxième volet concerne la proposition originale d'un protocole d'accès au médium efficace en énergie nommé " T-TMAC " et adapté à l'application, permettant d'organiser les échanges des messages dans l'architecture du réseau retenu. L'originalité du protocole est qu'il est composé de mécanismes de maintenance performants permettant la gestion de la mobilité et la reconfiguration du réseau (ajout et suppression d'un capteur). Pour cela, une adaptation et un paramétrage du standard IEEE 802.15.4 sont proposés. Le dernier volet présente l'évaluation et l'analyse de performances du protocole développé dans le cadre de scé narios de tests. Nous avons étudié en particulier l'impact de la taille des données et la périodicité de transfert sur l'énergie et le délai. Le protocole est validé à l'aide d'un modèle analytique dont les résultats ont été comparés à ceux obtenus par prototypage matériel.
199

[en] PERFORMANCE OF ENERGY EFFICIENT ALGORITHMS IN WSN / [pt] ANÁLISE DE DESEMPENHO DE ALGORITMOS DE EFICIÊNCIA ENERGÉTICA EM RSSF

JOSE MAURICIO NAVA AUZA 05 October 2018 (has links)
[pt] As redes de sensores sem fio se constituem numa área que outorga grandes oportunidades para a oferta de uma série de aplicações inovadoras e com baixo custo. Os dispositivos destas redes são bastantes pequenos e sua fonte de alimentação são baterias. O tempo de vida destas é limitado, limitando assim o tempo da vida dos sensores e da rede como um todo. Por esta razão nos últimos anos o tema de eficiência energética tem atraído grande interesse de pesquisadores. O aumento do custo da energia e do consumo global da energia pelo setor de ICT (Information and Communications Technologies) têm crescido vertiginosamente devido ao aumento continuo do número de clientes e da demanda por aplicações de maior complexidade. Por tudo isso têm sido desenvolvidos distintos métodos e técnicas para economizar energia nas RSSF. Neste trabalho se implementam dois algoritmos que levam em conta critérios para economizar os custos de energia da rede e através de experimentos de simulação se avalia os mesmos. Nos resultados pode se observar as vantagens de trabalhar com sistemas que visam a eficiência energética. / [en] The WSNs (Wireless Sensor Networks) belong to an area that gives rise to great opportunities to spread innovative and low cost applications. These kinds of networks are composed of tiny devices with limited energy. The main source of power supply for WSNs are batteries, which are limited in cycle life, thus limiting the sensors lifetime and the network as a whole. Due to that fact, the energy efficiency network is becoming the main concern to be addressed by researchers. Rising energy prices and global energy consumption by the ICT (Information and Communications Technologies) sector have grown dramatically due to the continuous increase in customer number and the demand for more complex applications. For the reasons outlined above, different energy-saving techniques for WSNs have been developed. Two energy-saving algorithms for WSNs were implemented in this thesis, and they were tested by experimental evaluation using simulation. The results obtained from the simulations showed the advantages of working with systems aiming at energy efficiency.
200

Middleware de serviços multi-camadas para redes de sensores sem fio

Ribeiro, José Eduardo 29 March 2010 (has links)
Made available in DSpace on 2016-06-02T19:05:42Z (GMT). No. of bitstreams: 1 3111.pdf: 9181760 bytes, checksum: dfefb6cfa06acf42fc5a6ea589d5a449 (MD5) Previous issue date: 2010-03-29 / Technological evolutions in the microelectronic systems and in the wireless communication allowed the development of devices called sensor nodes, which are smalles have low cost and low energy consumption. The sensor nodes integrate sensing modules, data processing and of wireless communication. The use of sensor nodes in a distributed way makes possible the communication among them providing the formation of the Wireless Sensor Networks (WSN). WSN are being used more and more as powerful monitoring tools of applications of environmental monitoring the monitoring of emergency situations in environments subject to risk situations to the life and the patrimony such as fire, leaks of poisonous gasses and explosions. Emergency management systems that integrate networks of wireless sensors have been used as support to the making of decision for response teams to the emergencies where the response time in these conditions becomes preponderant factor, aiming at the success of rescue practical operations. In order to the system of emergency management to be efficient a support layer to provide integration and reusability of the services is necessary supplied by the system besides a solution to abstract all the communication complexity and data processing inside WSN. In this work a middleware for WSN was designed and partially implemented to aid the work of the developers applications. The main characteristics of this middleware are to supply an expressive and flexible mechanism for subscriptions of interest of the application in the WSN and reusable interfaces that use technologies standard of the Web to provide interoperability between the services and applications. An initial evaluation accomplished with a prototype of some functions of the middleware. An estimate of occupation of memory in the sensor nodes was made with base in studies reported in the literature, and display that middleware projected is viable for the platform of the hardware of motes Mica 2. The mote Mica 2 is the third generation of commercial sensor nodes of the mica family motes, used to enable low energy in WSN. / Evoluções tecnológicas nos sistemas de microeletrônicos e na comunicação sem fio permitiram o desenvolvimento de dispositivos chamados nós sensores, que são pequenos, de baixo custo e de baixo consumo de energia. Os nós sensores integram módulos de sensoriamento, processamento de dados e de comunicação sem fio. A utilização dos nós sensores de forma distribuída possibilita a comunicação entre eles proporcionando a formação das Redes de Sensores Sem Fios (RSSFs). RSSFs estão sendo utilizadas cada vez mais como poderosas ferramentas de monitoramento, de aplicações de monitoramento ambiental a monitoramento de situações de emergência em ambientes sujeitos a situações de risco à vida e ao patrimônio, tais como incêndios, vazamento de gases tóxicos e explosões. Sistemas de gerenciamento da emergência que integram redes de sensores sem fio são utilizados como apoio à tomada de decisão para equipes de resposta a emergências em que o tempo-resposta nessas condições se torna fator preponderante visando o sucesso de operações práticas de salvamento. Para que o sistema de gerenciamento de emergência seja eficaz é necessária uma camada de suporte para prover integração e reusabilidade dos serviços fornecidos pelo sistema, além de uma solução para abstrair toda a complexidade de comunicação e processamento de dados no interior da RSSF. Neste trabalho, um middleware para RSSFs foi projetado e parcialmente implementado, para auxiliar o trabalho dos desenvolvedores de aplicações. As principais características deste middleware são fornecer um mecanismo expressivo e flexível para subscrições de interesse das aplicações na RSSFs e interfaces reusáveis que utilizam tecnologias padrão da Web para prover interoperabilidade entre os serviços e aplicações. Uma avaliação inicial foi realizada com um protótipo de algumas funções do middleware. Uma estimativa de ocupação de memória nos nós sensores foi feita com base em estudos reportados na literatura, e mostra que o middleware projetado é viável para a plataforma de hardware dos motes Mica 2. O mote Mica 2 é a terceira geração de nós sensores comerciais da família Mica motes, usado para capacitar baixa energia em RSSFs.

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