17 research outputs found

    Preliminary study on a novel Optimal Placed Sensors method based on Genetic Algorithm

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    The safeguarding of the historical and cultural heritage is one of the main research topics that has been addressed in recent years. Particular attention was given to the development of structural health monitoring systems that allowed the real time acquisition of different physical quantities that are stored in a cloud and compared with the health limit values of the structures obtained from numerical analysis previously carried out. One of the major problems highlighted by the use of these systems is related to the position and quantity of smart sensors to be used within the structure to be monitored. To avoid this, in this paper an Optimal Sensors Placement method was applied to a case study located in China. In particular, the positioning of the sensors was identified through an optimization workflow that adopt a Multi Objective Optimization engine called "Octopus"in Grasshopper3D. The identified optimal solutions have made it possible to detect the areas of the structure that will be subject to collapse during a seismic event

    Percolation Driven Floodingf or Energy Efficient Routing in Dense Sensor Networks, Journal of Telecommunications and Information Technology, 2009, nr 2

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    Simple flooding algorithms are widely used in ad hoc sensor networks either for information dissemination or as building blocks of more sophisticated routing protocols. In this paper a percolation driven probabilistic flooding algorithm is proposed, which provides large message delivery ratio with small number of sent messages, compared to traditional flooding. To control the number of sent messages the proposed algorithm uses locally available information only, thus induces negligible overhead on network traffic. The performance of the algorithm is analyzed and the theoretical resultsare verified through simulation examples

    Modulation Schemes and Connectivity in Wireless Underground Channel

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    In this chapter, a thorough treatment of the modulation schemes for UG Wireless is presented. The effects of soil texture and water content on the capacity of multi-carrier modulation in WUC are discussed. The multi-carrier capacity model results are analyzed. Moreover, the underground MIMO design for underground communications is explained thoroughly. An analysis of medium access in wireless underground is done as well. Furthermore, the soil properties are considered for cross-layer communications of UG wireless. The performance analysis of traditional modulation schemes is also considered. The soil moisture-based modulation approach is also explored in this chapter. The connectivity and diversity reception approaches are discussed for wireless underground communications. The connectivity and interference models are studied for Ad-Hoc and Hybrid Networks. The topology control mechanisms for maintaining network connectivity are explored for maximizing network capacity under the physical models (e.g., the protocol interference model and physical interference model). Moreover, the underground diversity is examined for 3W-Rake receiver and coherent detection along with experimental evaluation and comprehensive analysis of performance of equalization techniques

    Improving network reliability by exploiting path diversity in ad hoc networks with bursty losses

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    In wireless mobile ad hoc networks, end-to-end connections are often subject to failures which do not make the connection non-operational indefinitely but interrupt the communication for intermittent short periods of time. These intermittent failures usually arise from the mobility of hosts, dynamics of the wireless medium or energy-saving mechanisms, and cause bursty packet losses. Reliable communication in this kind of an environment is becoming more important with the emerging use of ad hoc networks for carrying diverse multimedia applications such as voice, video and data. In this thesis, we present a new path reliability model that captures intermittent availability of the paths, and we devise a routing strategy based on our path reliability model in order to improve the network reliability. Our routing strategy takes the advantage of path diversity in the network and uses a diversity coding scheme in order not to compromise efficiency. In diversity coding scheme, if the original information is encoded by using a (N,K) code, then it is enough for the destination to receive any K bits correctly out of N bits to successfully decode the original information. In our scheme, the original information is divided into N subpackets and subpackets are distributed among the available disjoint paths in the network. The distribution of subpackets among the diverse paths is a crucial decision. The subpackets should be distributed 'intelligently' so that the probability of successful reconstruction of the original information is maximized. Given the failure statistics of the paths, and the code rate (N, K), our strategy determines the allocation of subpackets to each path in such a manner that the probability of reconstruction of the original information at the destination is maximized. Simulation results justify the accuracy and efficiency of our approach. Additionally, simulation results show that our multipath routing strategy improves the network reliability substantially compared to the single path routing. In wireless networks, a widely used strategy is to place the nodes into a low energy consuming sleep mode in order to prolong the battery life. In this study, we also consider the cases where the intermittent availability of the nodes is due to the sleep/awake cycles of wireless nodes. A sleep/awake scheduling strategy is proposed which minimizes the packet latency while satisfying the energy saving ratio specified by the energy saving mechanism
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