- Wireless Sensor Networks, Optimization (Mathematics), Mobile Robotics, Computational Geometry, Vehicular Ad Hoc Networks, Artifical Intelligence, and 12 moreOptical Networks, Wireless Body Area Network (WBAN), Multi-Agent Systems and Autonomous Agents, Molecular Communication, Nanonetworks, Computational Topology, Self Organizing Networks, Computer Science, Artificial Intelligence, Robotics, Nanoscience, and Nanotechnologyedit
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Large scale coverage holes (CHs) resulting from correlated node failures, can significantly degrade quality of service and also jeopardise the integrity of WSNs. In the absence of centralised control, the distributed relocation of... more
Large scale coverage holes (CHs) resulting from correlated node failures, can significantly degrade quality of service and also jeopardise the integrity of WSNs. In the absence of centralised control, the distributed relocation of deployed nodes becomes a promising solution especially in harsh and hostile environments. In this paper, a distributed method is proposed that enables a network to partially or entirely repair itself through a collection of distributed movements of disjoint spanned trees (DS-Trees) towards the CHs. DS-Trees are spanned based on the nodes distances from the CHs, which are autonomously perceived by the nodes and their one-hop neighbours. DS-Trees around the CHs are spanned in a downstream style outwards from the holes, as nodes select their parents based on the minimum distance to the CH from their neighbours; nodes then decide whether or not to follow the movements of their DS-Trees parents. To examine the efficiency of the proposed model, its performance is compared with two Voronoi-based and one force-based node relocation algorithms. Results show that the proposed DS-Tree model either outperforms or matches the alternative approaches across a wide range of scenarios.
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A multiuser multi-input multi-output (MU-MIMO) downlink system with block diagonalization-based precoding is presented with a study of the impact of limited bandwidth resource for the feedback-links on the sum capacity. The channel... more
A multiuser multi-input multi-output (MU-MIMO) downlink system with block diagonalization-based precoding is presented with a study of the impact of limited bandwidth resource for the feedback-links on the sum capacity. The channel estimation is acquired at each user via downlink training, and the linear quantized form of estimated channels is fed back to the base station (BS) via noisy, finite-rate channel state information (CSI) feedback-links. Two architectures for CSI feedback are considered: parallel feedback where there is a feedback-link for each user; and serial feedback where a single feedback-link is used for all the users. The sum capacity is formulated as a function of the link parameters, enabling optimization of the number of training symbols and required feedback bits with the criterion of maximum sum capacity. The approach allows a performance comparison for different feedback architectures, the number of transmit antennas, and the number of users. The effect of time variations of the channel is analyzed via simulation, quantifying the loss of sum capacity relative to the case with perfect CSI for different Doppler frequencies.
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Coverage holes (CHs) can compromise the reliability and functionality of wireless sensor networks. The recovery of CHs is challenging, especially in distributed applications where sensors have little knowledge about other sensors'... more
Coverage holes (CHs) can compromise the reliability and functionality of wireless sensor networks. The recovery of CHs is challenging, especially in distributed applications where sensors have little knowledge about other sensors' actions. We propose a new game theoretic approach for recovering the CHs in a distributed manner. The key idea is that we formulate a potential game between the sensors, where each mobile sensor in the network only depends on local knowledge of its neighboring nodes and takes CH recovery actions recursively with global convergence. An appropriate combined action of physical relocation and sensing range adjustment can be taken by each sensor to reduce the CHs in an energy-efficient way. Simulation results show that the proposed game theoretic approach is able to substantially increase network lifetime and maintain network coverage in the presence of random damage events, as compared with the prior counterpart(s).
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Coverage holes (CHs) due to the correlated node failures, if not appropriately addressed in a timely manner, not only disrupt network's operation but also can compromise its integrity. In the absence of centralised control,... more
Coverage holes (CHs) due to the correlated node failures, if not appropriately addressed in a timely manner, not only disrupt network's operation but also can compromise its integrity. In the absence of centralised control, distributed node relocation can be an effective solution to recover CHs. Relocation algorithms that mainly applied to all nodes to address networks' coverage and unbalanced deployments problems, are not efficient as participating nodes beyond a certain distance and depth from the CHs do not significantly contribute to recovery of CHs. Here, the effects of the number of participating nodes and movement iterations on recovery of CHs are examined in two Voronoi-based and one force-based node relocation algorithms.
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In this paper, we have proposed a secure semi-fragile watermarking technique for content authentication of digital images. A binary image is encrypted in an efficient way and then embedded as the watermark for tamper detection. The... more
In this paper, we have proposed a secure semi-fragile watermarking technique for content authentication of digital images. A binary image is encrypted in an efficient way and then embedded as the watermark for tamper detection. The watermark is embedded by applying a quantization index modulation process on Euclidean norm of singular values of blocks in the wavelet domain. To avoid
Research Interests: Statistics, Statistical Analysis, Watermarking, Cryptography, Encryption, and 11 moreAuthentication, Quantization, Digital Images, Wavelet Transforms, Information Communication, Statistical Model, Digital Image, Discrete Wavelet Transforms, Discrete Cosine Transforms, Message Authentication, and Quantization Index Modulation
Abstract In this paper, we present an orthonormal version of the new information criterion (NIC) algorithm for fast estimation and tracking of signal subspace using a two-layer linear neural network (NN). The fast orthonormal NIC referred... more
Abstract In this paper, we present an orthonormal version of the new information criterion (NIC) algorithm for fast estimation and tracking of signal subspace using a two-layer linear neural network (NN). The fast orthonormal NIC referred as to FONIC algorithm guarantees the orthonormality of the weight matrix at each iteration. The proposed FONIC algorithm has a linear complexity which makes it efficient in real time applications. The FONIC algorithm provides a fast on-line learning of the optimum weights for the two-layer linear. Simulation ...
Research Interests: Signal Processing, Iterative Methods, Neural Networks, Automation & COntrol, Neural Network, and 11 moreSensor Arrays, Adaptive Signal Processing, Tracking, Random Processes, Mathematical Model, Linear Systems, Real Time Application, On line learning, Covariance Matrix, Adaptive Algorithm, and Multiple Signal Classification
In this paper, we consider the problem of passive localization and tracking of multiple sources in near field. For high resolution source localization, the multiple signal classification (MUSIC) algorithm can be extended to its 2-D... more
In this paper, we consider the problem of passive localization and tracking of multiple sources in near field. For high resolution source localization, the multiple signal classification (MUSIC) algorithm can be extended to its 2-D version by accounting for ...
Page 1. Robustness Evaluation of OFDM and MC-DS-CDMA Systems in Digital High Voltage Power Line Communication Systems by Using LS Channel Estimation Technique H. Atefat Doost * * Fars Regional Electric Company ...
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The use of Probabilistic Neural Network (PNN) is very common in supervised pattern recognition applications. PNN is based on Bayes decision rule and it uses Gaussian Parzen windows for estimating the probability density functions (pdf)... more
The use of Probabilistic Neural Network (PNN) is very common in supervised pattern recognition applications. PNN is based on Bayes decision rule and it uses Gaussian Parzen windows for estimating the probability density functions (pdf) required in Bayes rule. The conventional PNN needs a single spread value for pdf estimation which is proportional to Gaussian window width. In this paper we will suggest the use of a multi-spread PNN structure whose spread values are estimated using the training data. In addition, we will ...
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Abstract Catastrophic events in wireless sensor networks can result in large holes in network coverage. Repair of such damage requires accurate identification of the proper subset of nodes which form the boundary of the damaged region,... more
Abstract Catastrophic events in wireless sensor networks can result in large holes in network coverage. Repair of such damage requires accurate identification of the proper subset of nodes which form the boundary of the damaged region, such that some of these nodes-- ...
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In this paper, we present a new algorithm for tracking the signal subspace recursively. It is based on a new interpretation of the signal subspace. We introduce a novel information criterion for signal subspace estimation. We show that... more
In this paper, we present a new algorithm for tracking the signal subspace recursively. It is based on a new interpretation of the signal subspace. We introduce a novel information criterion for signal subspace estimation. We show that the solution of the proposed constrained optimization problem results the signal subspace. In addition, we introduce three adaptive algorithms which can be used for real time implementation of the signal subspace tracking. The computational complexity of the proposed signal subspace tracking algorithms are O(nr 2) which is much less than the direct computation of singular value decomposition or even some algorithms. Simulation results in the direction of arrival (DOA) tracking context depict excellent performance of the proposed algorithm.