168 research outputs found

    A new wireless underground network system for continuous monitoring of soil water contents

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    A new stand-alone wireless embedded network system has been developed recently for continuous monitoring of soil water contents at multiple depths. This paper presents information on the technical aspects of the system, including the applied sensor technology, the wireless communication protocols, the gateway station for data collection, and data transfer to an end user Web page for disseminating results to targeted audiences. Results from the first test of the network system are presented and discussed, including lessons learned so far and actions to be undertaken in the near future to improve and enhance the operability of this innovative measurement approac

    Standards-Based Wireless Sensor Networking Protocols for Spaceflight Applications

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    Wireless sensor networks (WSNs) have the capacity to revolutionize data gathering in both spaceflight and terrestrial applications. WSNs provide a huge advantage over traditional, wired instrumentation since they do not require wiring trunks to connect sensors to a central hub. This allows for easy sensor installation in hard to reach locations, easy expansion of the number of sensors or sensing modalities, and reduction in both system cost and weight. While this technology offers unprecedented flexibility and adaptability, implementing it in practice is not without its difficulties. Recent advances in standards-based WSN protocols for industrial control applications have come a long way to solving many of the challenges facing practical WSN deployments. In this paper, we will overview two of the more promising candidates - WirelessHART from the HART Communication Foundation and ISA100.11a from the International Society of Automation - and present the architecture for a new standards-based sensor node for networking and applications research

    Energy Efficient and Reliable Wireless Sensor Networks - An Extension to IEEE 802.15.4e

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    Collecting sensor data in industrial environments from up to some tenth of battery powered sensor nodes with sampling rates up to 100Hz requires energy aware protocols, which avoid collisions and long listening phases. The IEEE 802.15.4 standard focuses on energy aware wireless sensor networks (WSNs) and the Task Group 4e has published an amendment to fulfill up to 100 sensor value transmissions per second per sensor node (Low Latency Deterministic Network (LLDN) mode) to satisfy demands of factory automation. To improve the reliability of the data collection in the star topology of the LLDN mode, we propose a relay strategy, which can be performed within the LLDN schedule. Furthermore we propose an extension of the star topology to collect data from two-hop sensor nodes. The proposed Retransmission Mode enables power savings in the sensor node of more than 33%, while reducing the packet loss by up to 50%. To reach this performance, an optimum spatial distribution is necessary, which is discussed in detail

    Supervisory Wireless Control for Critical Industrial Applications

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    Filtered multi-carrier modulations for industrial wireless communications based on cognitive radio

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    Doktoretza-tesi honetako helburu nagusia, hari gabeko komunikazio industrialetarako fidagarritasun maila onargarria eman dezakeen maila fisikoko modulazio bat aurkitzea da. Eremu industrialetako radio bidezko kanaletan ematen diren komunikazioetarako baldintza bereziki aurkakoak direla eta, helburu hori lortzea benetako erronkatzat jo liteke. Gainera, modulazio horrek \Radio Cognitiva" deritzoten teknikekin bateragarria izan beharra dauka, hauek hari gabeko komunikazioen fidagarritasuna hobetzeko gaitasuna baitute. Bibliografian oinarrituz, gaur egungo baliabideekin hari gabeko komunikazio industrial kasu ugariri konponbidea emateko aukera badela ondoriozta genezake, baina ez kasu guztiei ordea. Hari gabeko kanalen egoera bereziki aurkakoa denerako eta komunikazio sistemek denbora muga bereziki zorrotzak bete behar dituztenerako, ezta erantzun nahikoa ona eman lezakeen hari gabeko komunikazio sistema industrialik bibliografia zientifikoan. Hori dela eta, doktoretza tesi honetan, \Radio Cognitiva" delakoa eta 5G-rako aurreikusita dauden filtro bankuetan oinarrituriko modulazio multigarraiatzaileak bezalako teknologia hasiberrietara jotzen dugu, aurrez aipaturiko arazoari konponbide berriak bilatu nahian. Bibliografian dauden filtro bankuetan oinarrituriko modulazio multi-garraiatzaileak aztertu eta ondoren beraien egokitasuna ebaluatzen dugu, kanal dispertsiboen aurkako sendotasuna eta \Radio Cognitiva" teknikekin izan lezaketen bateragarritasuna irizpide hartuz. Ebaluaketa horretan oinarrituz, doktoretza-tesi honetan \Radio Cognitiva" teknikekin bateragarria den WCP-COQAM proposatzen dugu modulazio industrial gisa. Modulazio teknika berau erakusteaz gain, bibliografian eskuragarri ez dauden WCP-COQAM-rentzat sinkronizazio eta kanal estimazio teknikak ere aurkezten ditugu.El objetivo principal de esta tesis doctoral consiste en encontrar una modulación de capa física capaz de proporcionar robustez y fiabilidad suficientes a sistemas de comunicaciones inalámbricas industriales. Esto supone un desafío, dadas las adversas condiciones del canal inalámbrico propias de entornos industriales. Además, dicha modulación debería presentar una alta compatibilidad con las técnicas de Radio Cognitiva, debido al potencial de éstas para mejorar la fiabilidad de las comunicaciones inalámbricas. Basándonos en la bibliografía, concluimos que las soluciones presentes en el estado del arte actual cubren una amplia variedad de escenarios dentro de las comunicaciones inalámbricas industriales, pero no todas. Para los escenarios con canales altamente dispersivos y requerimientos de tiempo especialmente estrictos, no existe ninguna solución en la industria ni dentro de la bibliografía científica. En esta tesis doctoral nos centramos en tecnologías incipientes como la Radio Cognitiva y las modulaciones multi-portadora con bancos de filtros para 5G para tratar de buscar nuevas soluciones al problema anteriormente descrito. Por lo tanto, analizamos algunas de las técnicas multi-portadora con bancos de filtros presentes en la bibliografía científica y las evaluamos basándonos en su robustez frente a canales altamente dispersivos y su compatibilidad con la Radio Cognitiva. Basándonos en dicha evaluación, proponemosWCP-COQAM como posible candidata a modulación industrial compatible con Radio Cognitiva. Además de la propia técnica de modulación, presentamos métodos de sincronización y estimación de canal para la misma que no se encuentran presentes en el estado del arte.The main goal of this doctoral thesis is to find a physical layer modulation able to provide high enough robustness and reliability levels for wireless industrial communications systems. Considering the harsh wireless channel conditions of industrial environments, that goal implies a considerable challenge. Besides, this modulation should be highly compatible with Cognitive Radio techniques, due to their potential to improve the reliability of wireless communications. Based on the bibliography, we conclude that the existent solutions in the current state of the art cover a wide range of wireless industrial communications scenarios, but not all of them. There is no solution, neither in the industry nor in the scientific bibliography, for those scenarios involving highly dispersive wireless channels and particularly stringent timeliness requirements. In this doctoral thesis, we focus on upcoming technologies such as Cognitive Radio and multi-carrier modulations based on filter banks for 5G, in order to search new solutions for the aforementioned problem. Therefore, we analyse some of the multi-carrier modulations based on filter banks of the scientific bibliography and we evaluate them in terms of robustness against highly dispersive channels and in terms of compatibility with Cognitive Radio. In this doctoral thesis we propose the modulation WCP-COQAM as possible candidate for industrial wireless modulation and compatible with Cognitive Radio. In addition to the modulation technique itself, we also introduce some synchronization and channel estimation techniques which are not present in the state of the art

    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

    Wireless Condition Monitoring of Machinery and Equipment in Maritime Industry: An Overview

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    Seagoing vessels are highly complex systems. Major requirements of marine vessels are continuous running time and high production output. As such, these systems require high availability and reliability, and are dependent on preventive maintenance procedures. Development of diverse range of sensors, combined with overall reduction in price, enabled implementation of condition based maintenance in such systems. Large increases in fuel cost, environmental restrictions and further crew reduction are current trend in maritime industry. Considering marine sector emphasis on the reduction of fuel consumption, environmental restrictions, and reduction of crew size, implementation of condition based maintenance is favourable, especially with regard to lost man-hours. However, high initial cost of installation on moving vessels, necessary crew training and additional sensor maintenance inhibits implementation of condition based maintenance. Replacing wired monitoring system with wireless ship-board sensor network would mitigate the above mentioned problems. However, current research of wireless sensor networks is based on terrestrial installation. This paper analyses the application of wireless sensor network technology on board seagoing vessels. Practical engineering solutions, including sensor types, configurations and wireless network topologies have been identified and reviewed
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