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.

A proposta deste trabalho foi o desenvolvimento de um protótipo composto por hardware e software de um sistema para o gerenciamento remoto de temperatura aplicado a aerogeradores de pequeno porte. O hardware microcontrolado (PIC16F877A) recebe e condiciona o sinal emitido por sensores de temperatura (termopares), executa um algoritmo e transmite a informação via rede sem fio (ZigBee) para um software instalado em um computador remoto. O software desenvolvido em linguagem de programação Delphi permite ao usuário monitorar online a temperatura e enviar sinais de comando para ligar e desligar cargas através do acionamento de relês presentes no cartão eletrônico (hardware). O sistema desenvolvido tem foco na aplicação de monitoramento de temperatura em pontos críticos dos aerogeradores de pequeno porte. O sistema permitirá inclusive que haja a intervenção do operador parando a máquina ou então acionando sistemas de refrigeração quando os limites de temperatura forem ultrapassados, visando prolongar a vida útil da máquina evitando falhas catastróficas e não catastróficas que possam inutilizar o equipamento e/ou oferecer algum tipo de risco ao meio em que se encontra. Com o objetivo de validar o desenvolvimento, o hardware implementado foi submetido a testes de validação de distância de comunicação apresentando resultado satisfatório, entretanto abaixo da especificação emitida pelo fabricante dos módulos ZigBee utilizados. O hardware e o software foram submetidos também à validação da precisão de medição da temperatura em uma máquina elétrica com características análogas aos pequenos aerogeradores onde apresentaram resultados aceitáveis para a aplicação proposta. / The proposal of this work was the development of a composed for the hardware and software of a system for the remote management of applied temperature the wind turbine of small transport. The microcontrolled hardware (PIC16F877A) receives and conditions the signal emitted for temperature sensors (thermocouples), executes an algorithm and transmits the information saw net without wire (ZigBee) for a software installed in a remote computer. The software developed in Delphi allows the user to monitor online the temperature and to send command signals to bind and disconnect loads through the drive of you reread gifts in the electronic card (the hardware). The developed system has focus in the application of monitoring of temperature in critical points of the wind turbine of small transport, also allowing that it has the intervention of the operator stopping the machine or then setting in motion refrigeration systems when the temperature limits will be exceeded, aiming at to draw out the useful life of the machine being prevented catastrophic failures and not catastrophic that can make unusable the equipment and/or offer some type of risk to the way where if it finds. With the objective to validate the development, the hardware implemented was submitted to validation tests of distance communication presenting satisfactory result, though below the specification issued by the manufacturer of ZigBee modules used. The hardware and software were also submitted to the validation of the accuracy of temperature measurement in an electric machine with features similar to small wind turbines which showed acceptable results for the proposed application.

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.

Physical indoor wireless network testbeds as well as outdoor wireless testbeds have the potential to accelerate the pace of research in the field of wireless ad hoc and mesh networking. They form part of a critical chain of steps needed to develop and test ad hoc networking protocols from concept to eventual uptake by industry. Current research in this area makes use of simulations or mathematical models which oversimplify the physical and Medium Access Control layer. In Africa specifically, wireless mesh networking has the potential to make a substantial impact on the lack of telecommunications infrastructure across the continent. A combination of good theoretical analysis, indoor test facilities and rural testbeds forms a perfect suite to carry out meaningful research in the field. A 7x7 wireless grid of closely spaced computers was constructed, making use of highly attenuated 802.11 radios running in ad hoc mode. Modelling and analysis revealed that a suitably attenuated environment was created with variation in signal strength between node pairs following a Gaussian distribution. This emulates a real outdoor network with normal signal propagation issues such as multi-path fading and lack of Fresnel zone clearance. This testbed was then used to evaluate 3 popular MANET ad hoc routing protocols, namely AODV, DYMO and OLSR. OLSR was tested with the standard hysteresis routing metric as well as the ETX routing metric. OLSR showed the best performance in terms of average throughput and packet loss for a medium size (21 node) and large (49 node) mesh network, with the hysteresis routing metric performing best in large networks and ETX performing best in medium sized networks. DYMO also performed very well, considering its low routing overhead, exhibiting the least amount of delay in a large mesh network (49 nodes). The AODV protocol showed the weakest performance in the grid with close to 60% of possible link pairs achieving no route in a 49-node grid. However, it did present the least amount of routing overhead compared with other routing protocols. Finally, a medium-sized rural mesh network testbed consisting of 9 nodes was built in a mountainous area of about 15 square kilometers around an AIDS clinic using the OLSR routing protocol with ETX as the routing metric. The network provided a good service to the satellite-based Internet with throughput rates ranging between 300 kbps for 4 hops and 11000 kbps for 1 hop and an average throughput rate of 2324 kbps. To encourage fair sharing of Internet connectivity, features were installed to limit each user to 40 MB/month of free Internet traffic. A local web server offers cached pages of Wikipedia and Linux repositories to reduce the need for Internet access. VoIP services were also installed between clinic infrastructure to reduce the the need for making expensive GSM calls. It was shown that a mesh network of this size provides a very satisfactory level of broadband service for users accessing a satellite-based Internet facility as well as local VoIP services. / Dissertation (MEng)--University of Pretoria, 2009. / Electrical, Electronic and Computer Engineering / unrestricted

No description available.

The aggregate interference distribution in cognitive radio networks is studied in a rigorous and analytical way using the popular Poisson point process model. While a number of results are available for this model for non-cognitive radio networks, cognitive radio networks present extra levels of difficulties for the analysis, mainly due to the exclusion region around the primary receiver, which are typically addressed via various ad-hoc approximations (e.g., based on the interference cumulants) or via the large-deviation analysis. Unlike the previous studies, we do not use here ad-hoc approximations but rather obtain the asymptotic interference distribution in a systematic and rigorous way, which also has a guaranteed level of accuracy at the distribution tail. This is in contrast to the large deviation analysis, which provides only the (exponential) order of scaling but not the outage probability itself. Unlike the cumulant-based analysis, our approach provides a guaranteed level of accuracy at the distribution tail. Additionally, our analysis provides a number of novel insights. In particular, we demonstrate that there is a critical transition point below which the outage probability decays only polynomially but above which it decays super-exponentially. This provides a solid analytical foundation to the earlier empirical observations in the literature and also reveals what are the typical ways outage events occur in different regimes. The analysis is further extended to include interference cancelation and fading (from a broad class of distributions). The outage probability is shown to scale down exponentially in the number of canceled nearest interferers in the below-critical region and does not change significantly in the above-critical one. The proposed asymptotic expressions are shown to be accurate in the non-asymptotic regimes as well.

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.

The sixth-generation (6G) of wireless communication systems will significantly rely on fog/edge network architectures for service provisioning. To satisfy stringent quality of service requirements using dynamically available resources at the edge, new network access schemes are needed. In this paper, we consider a cognitive dynamic edge/fog network where primary users (PUs) may temporarily share their resources and act as fog nodes for secondary users (SUs). We develop strategies for distributed dynamic fog probing so SUs can find out available connections to access the fog nodes. To handle the large-state space of the connectivity availability that includes availability of channels, computing resources, and fog nodes, and the partial observability of the states, we design a novel distributed Deep Q-learning Fog Probing (DQFP) algorithm. Our goal is to develop multi-user strategies for accessing fog nodes in a distributed manner without any centralized scheduling or message passing. By using cooperative and competitive utility functions, we analyze the impact of the multi-user dynamics on the connectivity availability and establish design principles for our DQFP algorithm.

This work studies the problem of indoor navigation, using wireless sensor networks. The knowledge of multiagent systems is being used in the process of solving this problem. Platform WSageNt, running on the operating system TinyOS, is being used for the execution of the agents. Agents themselves on the WSageNt platform are created in the language ALLL, which is described in the process. With use of those technologies, a solution is proposed as an extension to the WSageNt plaform and three agents, which fulfill the desired functionality. Then the implementation of this solution is described, followed by its testing, stating advantages and disadvantages of the created system.

The purpose of the thesis is to design and physically implement a system for location of devices in a Wi-Fi based networks deployed in the interior of small and medium-sized enterprises. First of all, the attention is given to the survey of commonly available technologies suitable for determination of the object position. Then, based on these findings, architecture of a location system comprising an array of sensor nodes and central processing unit is proposed. In conclusion, the results are presented and the fulfillment of the requirements is evaluated.