In hybrid wireless sensor networks composed of both static and mobile sensor nodes, the random deployment of stationary nodes may cause coverage holes in the sensing field. Hence, mobile sensor nodes are added after t...In hybrid wireless sensor networks composed of both static and mobile sensor nodes, the random deployment of stationary nodes may cause coverage holes in the sensing field. Hence, mobile sensor nodes are added after the initial deployment to overcome the coverage holes problem. To achieve optimal coverage, an efficient algorithm should be employed to find the best positions of the additional mobile nodes. This paper presents a genetic algorithm that searches for an optimal or near optimal solution to the coverage holes problem. The proposed algorithm determines the minimum number and the best locations of the mobile nodes that need to be added after the initial deployment of the stationary nodes. The performance of the genetic algorithm was evaluated using several metrics, and the simulation results demonstrated that the proposed algorithm can optimize the network coverage in terms of the overall coverage ratio and the number of additional mobile nodes.展开更多
With the expansive demand for video streaming over mobile networks,it is necessary to adopt schemes that balance the need for high video quality with the available network resources when streaming or downloading the v...With the expansive demand for video streaming over mobile networks,it is necessary to adopt schemes that balance the need for high video quality with the available network resources when streaming or downloading the video.Several approaches were proposed in the literature,including Dynamic Adaptive Streaming over HTTP(DASH).In this work,we consider an approach in which we place sufficient emphasis on the constrained battery resources in mobile devices when making decisions on the quality(or bitrate)of the video to be requested.This is done by using a fuzzy logic controller that enhances the performance of the Fuzzy-based DASH(FDASH)scheme.Simulation results show that our proposed approach conserves more energy than its predecessor while maintaining similar video quality and avoiding playback interruptions.展开更多
Wireless Sensor Networks (WSNs) are resource-constrained networks in which sensor nodes operate in an aggressive and uncontrolled environment and interact with sensitive data. Traffic aggregated by sensor nodes is sus...Wireless Sensor Networks (WSNs) are resource-constrained networks in which sensor nodes operate in an aggressive and uncontrolled environment and interact with sensitive data. Traffic aggregated by sensor nodes is susceptible to attacks and, due to the nature of WSNs, security mechanisms used in wired networks and other types of wireless networks are not suitable for WSNs. In this paper, we propose a mechanism to assure information security against security attacks and particularly node capturing attacks. We propose a cluster security management protocol, called Cryptographic Checksum Clustering Security Management (C3SM), to provide an efficient decentralized security management for hierarchal networks. In C3SM, every cluster selects dynamically and alternately a node as a cluster security manager (CSM) which distributes a periodic shared secrete key for all nodes in the cluster. The cluster head, then, authenticates identity of the nodes and derive a unique pairwise key for each node in the cluster. C3SM provides sufficient security regardless how many nodes are compromised, and achieves high connectivity with low memory cost and low energy consumption. Compared to existing protocols, our protocol provides stronger resilience against node capture with lower key storage overhead.展开更多
文摘In hybrid wireless sensor networks composed of both static and mobile sensor nodes, the random deployment of stationary nodes may cause coverage holes in the sensing field. Hence, mobile sensor nodes are added after the initial deployment to overcome the coverage holes problem. To achieve optimal coverage, an efficient algorithm should be employed to find the best positions of the additional mobile nodes. This paper presents a genetic algorithm that searches for an optimal or near optimal solution to the coverage holes problem. The proposed algorithm determines the minimum number and the best locations of the mobile nodes that need to be added after the initial deployment of the stationary nodes. The performance of the genetic algorithm was evaluated using several metrics, and the simulation results demonstrated that the proposed algorithm can optimize the network coverage in terms of the overall coverage ratio and the number of additional mobile nodes.
文摘With the expansive demand for video streaming over mobile networks,it is necessary to adopt schemes that balance the need for high video quality with the available network resources when streaming or downloading the video.Several approaches were proposed in the literature,including Dynamic Adaptive Streaming over HTTP(DASH).In this work,we consider an approach in which we place sufficient emphasis on the constrained battery resources in mobile devices when making decisions on the quality(or bitrate)of the video to be requested.This is done by using a fuzzy logic controller that enhances the performance of the Fuzzy-based DASH(FDASH)scheme.Simulation results show that our proposed approach conserves more energy than its predecessor while maintaining similar video quality and avoiding playback interruptions.
文摘Wireless Sensor Networks (WSNs) are resource-constrained networks in which sensor nodes operate in an aggressive and uncontrolled environment and interact with sensitive data. Traffic aggregated by sensor nodes is susceptible to attacks and, due to the nature of WSNs, security mechanisms used in wired networks and other types of wireless networks are not suitable for WSNs. In this paper, we propose a mechanism to assure information security against security attacks and particularly node capturing attacks. We propose a cluster security management protocol, called Cryptographic Checksum Clustering Security Management (C3SM), to provide an efficient decentralized security management for hierarchal networks. In C3SM, every cluster selects dynamically and alternately a node as a cluster security manager (CSM) which distributes a periodic shared secrete key for all nodes in the cluster. The cluster head, then, authenticates identity of the nodes and derive a unique pairwise key for each node in the cluster. C3SM provides sufficient security regardless how many nodes are compromised, and achieves high connectivity with low memory cost and low energy consumption. Compared to existing protocols, our protocol provides stronger resilience against node capture with lower key storage overhead.
