21 research outputs found

    Wireless networks in industrial environments: state of the art and issues

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    Wireless is everywhere nowadays and WLAN (i.e. 802.11 standard family) has became used by almost any communications devices in the mass market. The recent achievements in the fields of modulation techniques, such as Spread Spectrum, coding methods, such as Turbocodes, CDMA2000, and frequencies allocation methods, such as OFDM and Frequency Hopping, has pushed the growing uses of reliable and low-cost wireless technologies. Among them the last standards are: IEEE 802.11 family (i.e. WiFi), HyperLAN and HyperLAN2, IEEE 802.15 (i.e. WPAN), IEEE 802.16 (i.e. WiMAX)… However, the industrial environments are not taken into consideration in the design of those standards, because its harsh constraints has specific characteristics (reliability, interferences with existing equipments, multi-path propagation, low-power consumption, real-time reconfiguration, security…) that need specific requirements and eventually standards. This paper will intent to give an overview of the wireless technologies and discusses the current and future possible technologies for the uses in the industrial environments (power plants and stations, factories, industrial buildings, automotive…). Our current works showed us that there is no perfect technology by it-self but the best trade-off solution is a hybrid architecture combining the right wired and wireless technologies.1st IFIP International Conference on Ad-Hoc NetWorkingRed de Universidades con Carreras en Informática (RedUNCI

    Wireless networks in industrial environments: state of the art and issues

    Get PDF
    Wireless is everywhere nowadays and WLAN (i.e. 802.11 standard family) has became used by almost any communications devices in the mass market. The recent achievements in the fields of modulation techniques, such as Spread Spectrum, coding methods, such as Turbocodes, CDMA2000, and frequencies allocation methods, such as OFDM and Frequency Hopping, has pushed the growing uses of reliable and low-cost wireless technologies. Among them the last standards are: IEEE 802.11 family (i.e. WiFi), HyperLAN and HyperLAN2, IEEE 802.15 (i.e. WPAN), IEEE 802.16 (i.e. WiMAX)… However, the industrial environments are not taken into consideration in the design of those standards, because its harsh constraints has specific characteristics (reliability, interferences with existing equipments, multi-path propagation, low-power consumption, real-time reconfiguration, security…) that need specific requirements and eventually standards. This paper will intent to give an overview of the wireless technologies and discusses the current and future possible technologies for the uses in the industrial environments (power plants and stations, factories, industrial buildings, automotive…). Our current works showed us that there is no perfect technology by it-self but the best trade-off solution is a hybrid architecture combining the right wired and wireless technologies.1st IFIP International Conference on Ad-Hoc NetWorkingRed de Universidades con Carreras en Informática (RedUNCI

    Power line communications: an implementation of a real time control architecture for smart grid

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    Negli ultimi anni è aumentata la presenza di risorse energetiche distribuite (DERs) nella rete elettrica. La visione della ``rete intelligente'' (Smart Grid) cerca di introdurre un'infrastruttura di controllo e di comunicazione di tipo distribuito in modo da sfruttare le potenzialità delle DERs e quindi potenziare e modernizzare la rete di distribuzione attuale. Applicandolo alle reti a bassa tensione, la cosiddetta ``Smart Microgrids'', si è sviluppato un banco di prova (testbed) che permette di dimostrare tecniche di riduzione delle perdite di distribuzione. La soluzione adottata bilancia localmente la potenza reattiva della microgrid attraverso il controllo delle risorse locali ottenendo una riduzione della corrente necessaria per alimentare la rete. Inoltre, vengono analizzati i vantaggi nell'usare la linea elettrica come mezzo di comunicazione e vengono evidenziati alcuni standard di comunicazion

    Timed power line data communication

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    With the ever increasing demand for data communication methods, power line communication has become an interesting alternative method for data communication. Power line communication falls into two categories: one for data transmission between sites in the power grid and the other for home or office networking. When considering home or office networking, existing methods are either too slow for tasks other than simple automation, or are very fast with a higher cost than necessary for the desired function. The objective in this work is to develop a lower cost communication system with an intermediate data transmission rate.At first glance, power line communication looks like a good option because of the availability of power outlets in every room of a building. However, the power conductors were installed solely for the purpose of distributing 60 Hz mains power and, for data signals, they exhibit very high attenuation, variable impedance and there is radio frequency shielding. Furthermore, many of the 60 Hz loads produce radio frequency interference that impedes data communication. Previous research has shown that much of the noise is time synchronous with the 60 Hz mains frequency and that the majority of data errors occur during these periods of high noise. This work develops a power line communication protocol that coordinates transmissions and uses only the predictable times of lower noise. Using a central control strategy, the power line 60 Hz mains signal is divided into 16 timeslots and each timeslot is monitored for errors. The central controller periodically polls all stations to learn which timeslots have low noise and it then controls all transmissions to make the best use of these good timeslots. The periodic polling allows the system to adapt to changes in electrical loading and noise. This control strategy has been achieved with modest complexity and laboratory measurements have shown throughput approaching 70% of the modem bit rate

    Security issues in Internet of Things

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    The main idea behind the concept of the Internet of Things (IoT) is to connect all kinds of everyday objects, thus enabling them to communicate to each other and enabling people to communicate to them. IoT is an extensive concept that encompasses a wide range of technologies and applications. This document gives an introduction to what the IoT is, its fundamental characteristics and the enabling technologies that are currently being used. However, the technologies for the IoT are still evolving and maturing, leading to major challenges that need to be solved for a successful deployment of the IoT. Security is one of the most significant ones. Security issues may represent the greatest obstacle to general acceptance of the IoT. This document presents an assessment of the IoT security goals, its threats and the security requirements to achieve the goals. A survey on a representative set of already deployed IoT technologies is done to assess the current state of the art with regards to security. For each solution, a description of its functionality, its security options and the issues found in the literature is given. Finally, the common issues are identified and a set of future solutions are given.La idea principal detrás del concepto de Internet de las cosas (IoT) es conectar todo tipo de objetos cotidianos, para permitir comunicarse entre sí y que personas se comuniquen con ellos. IoT es un amplio concepto que abarca una extensa gama de tecnologías y aplicaciones. Este documento da una introducción a lo que es el IoT, sus características fundamentales y las tecnologías que se están utilizando actualmente. Sin embargo, las tecnologías usadas en el IoT todavía están en evolución y madurando, dando lugar a grandes desafíos que deben resolverse para un despliegue exitoso del IoT. La seguridad es uno de las más significativos. Los problemas de seguridad pueden representar el mayor obstáculo para la aceptación general del IoT. Este documento presenta una evaluación de los objetivos de seguridad en el IoT, sus amenazas y los requisitos necesarios para alcanzar dichos objetivos. Se realiza un estudio sobre un conjunto representativo de tecnologías IoT en uso para evaluar su estado actual respecto a la seguridad. Para cada solución, se da una descripción de su funcionalidad, sus protecciones y los problemas encontrados. Finalmente, se identifican los problemas comunes y se dan un conjunto de soluciones futuras.La idea principal darrera del concepte d'Internet de les coses (IoT) és connectar tot tipus d'objectes quotidians, per permetre comunicar-se entre sí i que les persones es comuniquin amb ells. IoT és un ampli concepte que engloba una extensa gamma de tecnologies i aplicacions. Aquest document dona una introducció al que és el IoT, les seves característiques fonamentals i les tecnologies que s'estan utilitzant actualment. No obstant, les tecnologies utilitzades en el IoT encara estan evolucionant i madurant, donant lloc a grans reptes que s'han de resoldre per a un desplegament exitós del IoT. La seguretat és un dels reptes més significatius. Els problemes de seguretat poden representar el major obstacle per l'acceptació general de l'IoT. Aquest document presenta una avaluació dels objectius de seguretat en el Iot, les seves amenaces i els requisits necessaris per assolir aquests objectius. Es realitza un estudi sobre un conjunt representatiu de tecnologies IoT en ús per avaluar el seu estat actual respecte a la seguretat. Per cada solució, es dona una descripció de la seva funcionalitat, les seves proteccions i els problemes trobats. Finalment, s'identifiquen els problemes comuns i es donen un conjunt de solucions futures

    Rural internet connectivity: a development in Dwesa-Cwebe, Eastern Cape, South Africa

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    This thesis presents aspects of Internet connectivity in rural South Africa. The work looks at government initiatives being undertaken to connect rural communities to up-to-date information networks. Various projects that seek to connect rural areas of South Africa, as well as other remote areas around the world, are discussed. These projects present many novel ideas that have been successfully used to link rural communities in remote areas with the information age. In particular, wired and wireless access technologies that can be implemented to connect remote communities to the Internet are discussed. A field test utilizing GPRS, VSAT and WiMAX was implemented in Dwesa-Cwebe, Eastern Cape Province, South Africa. VSAT proved to offer better Internet connectivity in terms of throughput and latency. WiMAX was then successfully implemented to relay the signal over the remote area of Dwesa-Cwebe, thus effectively providing Internet connectivity to an area with limited cell phone coverage and no telephone lines
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