555 research outputs found

    Robust Controller for Delays and Packet Dropout Avoidance in Solar-Power Wireless Network

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    Solar Wireless Networked Control Systems (SWNCS) are a style of distributed control systems where sensors, actuators, and controllers are interconnected via a wireless communication network. This system setup has the benefit of low cost, flexibility, low weight, no wiring and simplicity of system diagnoses and maintenance. However, it also unavoidably calls some wireless network time delays and packet dropout into the design procedure. Solar lighting system offers a clean environment, therefore able to continue for a long period. SWNCS also offers multi Service infrastructure solution for both developed and undeveloped countries. The system provides wireless controller lighting, wireless communications network (WI-FI/WIMAX), CCTV surveillance, and wireless sensor for weather measurement which are all powered by solar energy

    Visible light and device-to-device communications: system analysis and implementation

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    MenciĂłn internacional en el tĂ­tulo de doctorRadio-frequency based wireless communications have revolutionized our society. Thanks to the important wireless communication technologiesWi-Fi, LTE, and so on, people can now enjoy high data rate and perversive connection while surfing the Internet. However, new problems and demands are rising in today’s wireless networks. Increasing capacity demands are requiring more bandwidth and various wireless radio technologies are exacerbating the spectrum problem. Now technologies and paradigms are needed to meet these needs. In this thesis, I investigate two technologies towards this direction: Visible Light Communication (VLC) and Device-to-Device (D2D) communication. Although more and more researchers are becoming interested in VLC, the lacking of an opensource platform for VLC research is perverting the fast investigations of VLC. To solve this problem, I design, implement, and evaluate the first open-source platform OpenVLC for embedded VLC research. OpenVLC employs cost-efficient and off-the-shelf optical components and electronics to provide a research platform. The software solutions are developed as a Linux driver and can easily connect to the TCP/IP layers. This allows for the adoption of various Linux diagnostic tools to evaluate the VLC’s properties and performance. Based on OpenVLC, I propose a new MAC protocol that enable the intra-frame bidirectional transmissions in networks of visible LEDs. The method adopts only a single LED at each node for both transmission and reception. Through this technology, the system’s throughput can be improved a lot and the hidden-node problem can be alleviated greatly. Motivated by the envision of the Internet of lights, I study how to provide stable visible light links in VLC. I identify the limitations and tradeoff of two different types of optical receivers photodiode and LED, and design and implement a new optical data link layer that was resilient to dynamic environments. On the other hands, to meet the increasing demands, small cells are proposed and deployed in latest cellular networks. As a result, the number of users served by each cell is decreasing. As the opportunistic gain increases as a concave function of active users, in small cells and when dynamic traffic load are considered, the opportunistic gain will lost. To recoup the opportunistic gain, I propose a base-station transparent method based on D2D communication to dispatch traffic among devices. Dynamic programming is used to find the optimal dispatching policy. The results show this method can improve the average packet transfer delay greatly. To increase the opportunistic gain by a further step, I propose a base-station initiated policy to solve the same problem. An algorithm is therefore designed and implemented, and its performance shows that it can reduce the frame loss ratio significantly.This work has been supported by IMDEA Networks InstitutePrograma Oficial de Doctorado en IngenierĂ­a TelemĂĄticaPresidente: Thiemo Voigt.- Secretario: Pablo Serrano Yåñez-Mingot.- Vocal: David Malon

    Sense and Respond

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    Over the past century, the manufacturing industry has undergone a number of paradigm shifts: from the Ford assembly line (1900s) and its focus on efficiency to the Toyota production system (1960s) and its focus on effectiveness and JIDOKA; from flexible manufacturing (1980s) to reconfigurable manufacturing (1990s) (both following the trend of mass customization); and from agent-based manufacturing (2000s) to cloud manufacturing (2010s) (both deploying the value stream complexity into the material and information flow, respectively). The next natural evolutionary step is to provide value by creating industrial cyber-physical assets with human-like intelligence. This will only be possible by further integrating strategic smart sensor technology into the manufacturing cyber-physical value creating processes in which industrial equipment is monitored and controlled for analyzing compression, temperature, moisture, vibrations, and performance. For instance, in the new wave of the ‘Industrial Internet of Things’ (IIoT), smart sensors will enable the development of new applications by interconnecting software, machines, and humans throughout the manufacturing process, thus enabling suppliers and manufacturers to rapidly respond to changing standards. This reprint of “Sense and Respond” aims to cover recent developments in the field of industrial applications, especially smart sensor technologies that increase the productivity, quality, reliability, and safety of industrial cyber-physical value-creating processes

    State of the art of cyber-physical systems security: An automatic control perspective

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    Cyber-physical systems are integrations of computation, networking, and physical processes. Due to the tight cyber-physical coupling and to the potentially disrupting consequences of failures, security here is one of the primary concerns. Our systematic mapping study sheds light on how security is actually addressed when dealing with cyber-physical systems from an automatic control perspective. The provided map of 138 selected studies is defined empirically and is based on, for instance, application fields, various system components, related algorithms and models, attacks characteristics and defense strategies. It presents a powerful comparison framework for existing and future research on this hot topic, important for both industry and academia

    On-Board Electronic Control Systems of Future Automated Heavy Machinery

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    The level of automation and wireless communication has increased in heavy machinery recently. This requires utilizing new devices and communication solutions in heavy machinery applications which involve demanding operating conditions and challenging life-cycle management. Therefore, the applied devices have to be robust and hardware architectures flexible, consisting of generic modules. In research and development projects devices that have various communication interfaces and insufficient mechanical and electrical robustness need to be applied. Although this thesis has its main focus on machines utilized as research platforms, many of the challenges are similar with commercial machines.The applicability of typical solutions for data transfer is discussed. Controller area network with a standardized higher level protocol is proposed to be applied where data signalling rates above 1 Mb/s are not required. The main benefits are the availability of robust, generic devices and well-established software tools for configuration management. Ethernet can be utilized to network equipment with high data rates, typically used for perception. Although deterministic industrial Ethernet protocols would fulfil most requirements, the conventional internet protocol suite is likely to be applied due to device availability.Sometimes sensors and other devices without a suitable communication interface need to be applied. In addition, device-related real-time processing or accurate synchronization of hardware signals may be required. A small circuit board with a microcontroller can be utilized as a generic embedded module for building robust, small and cost-efficient prototype devices that have a controller area network interface. Although various microcontroller boards are commercially available, designing one for heavy machinery applications, in particular, has benefits in robustness, size, interfaces, and flexible software development. The design of such a generic embedded module is presented.The device-specific challenges of building an automated machine are discussed. Unexpected switch-off of embedded computers has to be prevented by the control system to avoid file system errors. Moreover, the control system has to protect the batteries against deep discharge when the engine is not running. With many devices, protective enclosures with heating or cooling are required.The electronic control systems of two automated machines utilized as research platforms are presented and discussed as examples. The hardware architectures of the control systems are presented, following the proposed communication solutions as far as is feasible. Several applications of the generic embedded module within the control systems are described. Several research topics have been covered utilizing the automated machines. In this thesis, a cost-efficient operator-assisting functionality of an excavator is presented and discussed in detail.The results of this thesis give not only research institutes but also machine manufacturers and their subcontractors an opportunity to streamline the prototyping of automated heavy machinery

    Industrial Wireless Sensor Networks

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    Wireless sensor networks are penetrating our daily lives, and they are starting to be deployed even in an industrial environment. The research on such industrial wireless sensor networks (IWSNs) considers more stringent requirements of robustness, reliability, and timeliness in each network layer. This Special Issue presents the recent research result on industrial wireless sensor networks. Each paper in this Special Issue has unique contributions in the advancements of industrial wireless sensor network research and we expect each paper to promote the relevant research and the deployment of IWSNs

    Building the Hyperconnected Society- Internet of Things Research and Innovation Value Chains, Ecosystems and Markets

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    This book aims to provide a broad overview of various topics of Internet of Things (IoT), ranging from research, innovation and development priorities to enabling technologies, nanoelectronics, cyber-physical systems, architecture, interoperability and industrial applications. All this is happening in a global context, building towards intelligent, interconnected decision making as an essential driver for new growth and co-competition across a wider set of markets. It is intended to be a standalone book in a series that covers the Internet of Things activities of the IERC – Internet of Things European Research Cluster from research to technological innovation, validation and deployment.The book builds on the ideas put forward by the European Research Cluster on the Internet of Things Strategic Research and Innovation Agenda, and presents global views and state of the art results on the challenges facing the research, innovation, development and deployment of IoT in future years. The concept of IoT could disrupt consumer and industrial product markets generating new revenues and serving as a growth driver for semiconductor, networking equipment, and service provider end-markets globally. This will create new application and product end-markets, change the value chain of companies that creates the IoT technology and deploy it in various end sectors, while impacting the business models of semiconductor, software, device, communication and service provider stakeholders. The proliferation of intelligent devices at the edge of the network with the introduction of embedded software and app-driven hardware into manufactured devices, and the ability, through embedded software/hardware developments, to monetize those device functions and features by offering novel solutions, could generate completely new types of revenue streams. Intelligent and IoT devices leverage software, software licensing, entitlement management, and Internet connectivity in ways that address many of the societal challenges that we will face in the next decade
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