224 research outputs found

    A Framework for WirelessHART Simulations

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    Due to stringent timing requirements of the WirelessHART protocol, we need to extend previously known hybrid simulation approaches with WirelessHART specific functionality. Because of intermediary devices that connect simulation and real environments a communication delay significantly exceeds time boundaries of a WirelessHART slot. Our solution is to add a WirelessHART-enabled intermediary device operating at the Physical and the Data Link layers that can handle time critical tasks of the WirelessHART protocol. This approach allows to evaluate the performance of a WirelessHART network and WirelessHART-enabled devices in a hybrid simulation environment

    Survey on wireless technology trade-offs for the industrial internet of things

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    Aside from vast deployment cost reduction, Industrial Wireless Sensor and Actuator Networks (IWSAN) introduce a new level of industrial connectivity. Wireless connection of sensors and actuators in industrial environments not only enables wireless monitoring and actuation, it also enables coordination of production stages, connecting mobile robots and autonomous transport vehicles, as well as localization and tracking of assets. All these opportunities already inspired the development of many wireless technologies in an effort to fully enable Industry 4.0. However, different technologies significantly differ in performance and capabilities, none being capable of supporting all industrial use cases. When designing a network solution, one must be aware of the capabilities and the trade-offs that prospective technologies have. This paper evaluates the technologies potentially suitable for IWSAN solutions covering an entire industrial site with limited infrastructure cost and discusses their trade-offs in an effort to provide information for choosing the most suitable technology for the use case of interest. The comparative discussion presented in this paper aims to enable engineers to choose the most suitable wireless technology for their specific IWSAN deployment

    Application of reinforcement learning with Q-learning for the routing in industrial wireless sensors networks

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    Industrial Wireless Sensor Networks (IWSN) usually have a centralized management approach, where a device known as Network Manager is responsible for the overall configuration, definition of routes, and allocation of communication resources. The routing algorithms need to ensure path redundancy while reducing latency, power consumption, and resource usage. Graph routing algorithms are used to address these requirements. The dynamicity of wireless networks has been a challenge for tuning and developing routing algorithms, and Machine Learning models such as Reinforcement Learning have been applied in a promising way in Wireless Sensor Networks to select, adapt and optimize routes. The basic concept of Reinforcement Learning is the existence of a learning agent that acts and changes the state of the environment, and receives rewards. However, the existing approaches do not meet some of the requirements of the IWSN standards. In this context, this thesis proposes the Q-Learning Reliable Routing approach, where the Q-Learning model is used to build graph routes. Two approaches are presented: QLRR-WA and QLRR-MA. QLRR-WA uses a learning agent that adjusts the weights of the cost equation of a state-of-the-art routing algorithm to reduce the latency and increase the network lifetime. QLRR-MA uses several learning agents so nodes can choose connections in the graph trying to reduce the latency. Other contributions of this thesis are the performance comparison of the state-of-the-art graph-routing algorithms and the evaluation methodology proposed. The QLRR algorithms were evaluated in a WirelessHART simulator, considering industrial monitoring applications with random topologies. The performance was analyzed considering the average network latency, network lifetime, packet delivery ratio and the reliability of the graphs. The results showed that, when compared to the state of the art, QLRR-WA reduced the average network latency and improved the lifetime while keeping high reliability, while QLRR-MA reduced latency and increased packet delivery ratio with a reduction in the network lifetime. These results indicate that Reinforcement Learning may be helpful to optimize and improve network performance.As Redes Industriais de Sensores Sem Fio (IWSN) geralmente tĂȘm uma abordagem de gerenciamento centralizado, onde um dispositivo conhecido como Gerenciador de Rede Ă© responsĂĄvel pela configuração geral, definição de rotas e alocação de recursos de comunicação. Os algoritmos de roteamento precisam garantir a redundĂąncia de caminhos para as mensagens, e tambĂ©m reduzir a latĂȘncia, o consumo de energia e o uso de recursos. O roteamento por grafos Ă© usado para alcançar estes requisitos. A dinamicidade das redes sem fio tem sido um desafio para o ajuste e o desenvolvimento de algoritmos de roteamento, e modelos de Aprendizado de MĂĄquina como o Aprendizado por Reforço tĂȘm sido aplicados de maneira promissora nas Redes de Sensores Sem Fio para selecionar, adaptar e otimizar rotas. O conceito bĂĄsico do Aprendizado por Reforço envolve a existĂȘncia de um agente de aprendizado que atua em um ambiente, altera o estado do ambiente e recebe recompensas. No entanto, as abordagens existentes nĂŁo atendem a alguns dos requisitos dos padrĂ”es das IWSN. Nesse contexto, esta tese propĂ”e a abordagem Q-Learning Reliable Routing, onde o modelo Q-Learning Ă© usado para construir os grafos de roteamento. Duas abordagens sĂŁo propostas: QLRR-WA e QLRR-MA. A abordagem QLRR-WA utiliza um agente de aprendizado que ajusta os pesos da equação de custo de um algoritmo de roteamento de estado da arte, com o objetivo de reduzir a latĂȘncia e aumentar a vida Ăștil da rede. A abordagem QLRR-MA utiliza diversos agente de aprendizado de forma que cada dispositivo na rede pode escolher suas conexĂ”es tentando reduzir a latĂȘncia. Outras contribuiçÔes desta tese sĂŁo a comparação de desempenho das abordagens com os algoritmos de roteamento de estado da arte e a metodologia de avaliação proposta. As abordagens do QLRR foram avaliadas com um simulador WirelessHART, considerando aplicaçÔes de monitoramento industrial com diversas topologias. O desempenho foi analisado considerando a latĂȘncia mĂ©dia da rede, o tempo de vida esperado da rede, a taxa de entrega de pacotes e a confiabilidade dos grafos. Os resultados mostraram que, quando comparado com o estado da arte, o QLRR-WA reduziu a latĂȘncia mĂ©dia da rede e melhorou o tempo de vida esperado, mantendo alta confiabilidade, enquanto o QLRR-MA reduziu a latĂȘncia e aumentou a taxa de entrega de pacotes, ao custo de uma redução no tempo de vida esperado da rede. Esses resultados indicam que o Aprendizado por Reforço pode ser Ăștil para otimizar e melhorar o desempenho destas redes

    Cyber-Physical Co-Design of Wireless Control Systems

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    Wireless sensor-actuator network (WSAN) technology is gaining rapid adoption in process industries because of its advantages in lowering deployment and maintenance cost in challenging environments. While early success of industrial WSANs has been recognized, significant potential remains in exploring WSANs as unified networks for industrial plants. This thesis research explores a cyber-physical co-design approach to design wireless control systems. To enable holistic studies of wireless control systems, we have developed the Wireless Cyber-Physical Simulator (WCPS), an integrated co-simulation environment that integrates Simulink and our implementation of WSANs based on the industrial WirelessHART standard. We further develop novel WSAN protocols tailored for advanced control designs for networked control systems. WCPS now works as the first simulator that features both linear and nonlinear physical plant models, state-of-art WirelessHART protocol stack, and realistic wireless network characteristics. A realistic wireless structural control study sheds light on the challenges of WSC and the limitations of a traditional structural control approach under realistic wireless conditions. Systematic emergency control results demonstrate that our real-time emergency communication approach enables timely emergency handling, while allowing regular feedback control loops to effectively share resources in WSANs during normal operations. A co-joint study of wireless routing and control highlights the importance of the co-design approach of wireless networks and control

    A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks

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    In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs

    Real-Time Sensor Networks and Systems for the Industrial IoT

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    The Industrial Internet of Things (Industrial IoT—IIoT) has emerged as the core construct behind the various cyber-physical systems constituting a principal dimension of the fourth Industrial Revolution. While initially born as the concept behind specific industrial applications of generic IoT technologies, for the optimization of operational efficiency in automation and control, it quickly enabled the achievement of the total convergence of Operational (OT) and Information Technologies (IT). The IIoT has now surpassed the traditional borders of automation and control functions in the process and manufacturing industry, shifting towards a wider domain of functions and industries, embraced under the dominant global initiatives and architectural frameworks of Industry 4.0 (or Industrie 4.0) in Germany, Industrial Internet in the US, Society 5.0 in Japan, and Made-in-China 2025 in China. As real-time embedded systems are quickly achieving ubiquity in everyday life and in industrial environments, and many processes already depend on real-time cyber-physical systems and embedded sensors, the integration of IoT with cognitive computing and real-time data exchange is essential for real-time analytics and realization of digital twins in smart environments and services under the various frameworks’ provisions. In this context, real-time sensor networks and systems for the Industrial IoT encompass multiple technologies and raise significant design, optimization, integration and exploitation challenges. The ten articles in this Special Issue describe advances in real-time sensor networks and systems that are significant enablers of the Industrial IoT paradigm. In the relevant landscape, the domain of wireless networking technologies is centrally positioned, as expected

    An open virtual testbed for industrial control system security research

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    ICS security has been a topic of scrutiny and research for several years, and many security issues are well known. However, research efforts are impeded by a lack of an open virtual industrial control system testbed for security research. This thesis describes a virtual testbed framework using Python to create discrete testbed components (including virtual devices and process simulators). This testbed is designed such that the testbeds are interoperable with real ICS devices and that the virtual testbeds can provide comparable ICS network behavior to a laboratory testbed. Two testbeds based on laboratory testbeds have been developed and have been shown to be interoperable with real industrial control systemequipment and vulnerable to attacks in the samemanner as a real system. Additionally, these testbeds have been quantitatively shown to produce traffic close to laboratory systems (within 90% similarity on most metrics)

    Wireless Cyber-Physical Simulator and Case Studies on Structural Control

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    Abstract: Wireless Structural Control (WSC) systems can play a crucial role in protecting civil infrastructure in the event of earthquakes and other natural disasters. Such systems represent an exemplary class of cyber-physical systems that perform close-loop control using wireless sensor networks. Existing WSC research usually employs wireless sensors installed on small lab structures, which cannot capture realistic delays and data loss in wireless sensor networks deployed on large civil structures. The lack of realistic tools that capture both the cyber (wireless) and physical (structural) aspects of WSC systems has been a hurdle for cyber-physical systems research for civil infrastructure. This advances the state of the art through the following contributions. First, we developed the Wireless Cyber-Physical Simulator (WCPS), an integrated environment that combines realistic simulations of both wireless sensor networks and structures. WCPS integrates Simulink and TOSSIM, a state-of-the-art sensor network simulator featuring a realistic wireless model seeded by signal traces. Second, we performed two realistic case studies each combining a structural model with wireless traces collected from real-world environments. The building study combines a benchmark building model and wireless traces collected from a multi-story building. The bridge study combines the structural model of the Cape Girardea
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