Search results for "Wireless"
showing 10 items of 879 documents
Low-Cost Alternatives for Urban Noise Nuisance Monitoring Using Wireless Sensor Networks
2015
Noise pollution caused by vehicular traffic is a common problem in urban environments that has been shown to affect people's health and children's cognition. In the last decade, several studies have been conducted to assess this noise, by measuring the equivalent noise pressure level (called L eq ) to acquire an accurate sound map using wireless networks with acoustic sensors. However, even with similar values of L eq , people can feel the noise differently according to its frequency characteristics. Thus, indexes, which can express people's feelings by subjective measures, are required. In this paper, we analyze the suitability of using the psychoacoustic metrics given by the Zwicker's mod…
Analysis of proposals to reduce SAR levels from GSM terminals
2002
Is wireless communication dangerous? In recent years some scientists and lay people have expressed alarm at the possible harm mobile phones could cause to the user's health, even cancer. Handset terminals must meet standard limits based in SAR measurements. In this paper we present several proposals to minimize SAR values computed over a numerical user's head model using absorbent materials and new generation antennas.
Cyber Security for Wireless Semantic (SCADA/DCS) Systems
2016
International audience; Supervisory Control and Data Acquisition and Distributed Control Systems named (SCADA/DCS) have played a key role in the design of modern power smart applications, particularly in the automatic management of real time energetic platforms. In this work, we present a semantic cyber security vulnerabilities add to classic one, with the use of semantic embedded application in smart devices in semantic wireless (SCADA/DCS) systems, focusing on the semantic attacks. In this work, we present a new security semantic wireless protocol as a secure communication support for these modern semantic wireless systems named (ZIGBEE/SOAP/SECURITY), obtained by the combination between …
Decentralized Synchronization for Zigbee wireless sensor networks in Multi-Hop Topology
2010
Abstract The most effective solution for energy saving in low-rate wireless sensor networks is maintaining each node in a doze state as long as possible. In order to guarantee network connectivity, the intervals at which the network sensors are turned on and off have to be coordinated. We analyze the Zigbee MAC performance in sensor networks deployed in multi-hop topologies. For this networks, critical inefficiencies can arise due to transmissions performed by hidden nodes. We evaluate the impact of different synchronization schemes on the network performance, both in terms of network capacity and in terms of energy consumption. We show how the synchronization function can be opportunistica…
A unified radio control architecture for prototyping adaptive wireless protocols
2016
Experimental optimization of wireless protocols and validation of novel solutions is often problematic, due to limited configuration space present in commercial wireless interfaces as well as complexity of monolithic driver implementation on SDR-based experimentation platforms. To overcome these limitations a novel software architecture is proposed, called WiSHFUL, devised to allow: i) maximal exploitation of radio functionalities available in current radio chips, and ii) clean separation between the logic for optimizing the radio protocols (i.e. radio control) and the definition of these protocols.
A Prototype of Wireless Sensor for Data Acquisition in Energy Management Systems
2018
A prototype of a wireless sensor for monitoring electrical loads in a smart building is designed and implemented. The sensor can acquire the main electrical parameters of the connected load and, optionally, other physical quantities (e.g., room temperature). Unlike other wireless sensors in literature, the proposed sensor is cheap and small, exploits the Wi-Fi network that is commonly available inside buildings, and uses a lightweight message-based communication paradigm. Besides the sensor node, two management nodes are also implemented to manage sensor reconfiguration and the persistence of data. The measured data are stored in an SQLite database and can be used for various purposes, e.g.…
Estimation of the Velocity of a Walking Person in Non-Stationary Indoor Environments from the Received RF Signal
2018
Accurate estimation of the time-variant (TV) velocity, i.e., TV speed and TV direction of motion, of walking persons in indoor environment is of great importance in a variety of wireless indoor applications. This paper presents a novel method for estimating the velocity of a walking person in three-dimensional indoor environments, which are assumed to be equipped with a distributed 3 × 3 multiple-input multiple-output (MIMO) system. The approach estimates the TV speed, TV vertical angle-of-motion (VAOM), and TV horizontal angle-of-motion (HAOM) by fitting the spectrogram of the complex channel gain of a non-stationary indoor channel model to the spectrogram obtained from the received radio …
CVS: Using VLANs to Counteract the Effect of Topology Changes in Quasi-Static Mesh Access Networks
2006
Mesh networks are candidate to play the role of switched Ethernet LANs over extended areas and with a sensibly higher flexibility. Actually, mesh networks can exploit both Ethernet and wireless technologies, e.g. Wi-Fi and/or free-space optical links, to provide a high degree of redundancy in an access network, and to provide users with powerful means to connect with each other. By using such technologies, the mesh topology remains stable for hours, so that the mesh topology can be considered quasi-static. However, large meshes require a heavy overhead in the network control plane as for the management of end-to-end paths, which can change due to mobility of users and due to occasional fail…
A study of mobility and reachability in ad hoc networks using stochastic activity networks
2006
The integration of ad-hoc networks into real environments is now becoming more and more common and supervision and control systems are no exception. The efficiency of the communication in these networks as well as various other factors, are governed by the working area, the number of nodes, mobility, transmission power, etc. In this paper, the mobility and reachability of mobile nodes appearing spontaneously in a large installation such as can be found in a water purification system are studied. These nodes form an ad-hoc network and communicate between each other in order to finally reach a fixed node which can offer them information from the rest of the system in real time or act as a gat…
Two Levels SPF-Based System to Interconnect Partially Decentralized P2P File Sharing Networks
2005
Partially decentralized P2P (PDP2P) networks are a subset of P2P networks. Roles of nodes are different according to their functionality in the network. Nowadays, there are many PDP2P networks, with different characteristics. It is necessary to find a way to join those autonomous networks. We have not found any interconnection system, so in this article we present a new hierarchical system for interconnecting peers from different PDP2P networks. It will allow sharing data, content and resources between networks. It can be employed between sensor networks, P2P networks, and generally, overlay networks. Oldest superpeers or brokers with higher bandwidth in the PDP2P network will belong to hig…