A novel joint optimization strategy for the secondary user( SU) was proposed to consider the short-term and long-term video transmissions over distributed cognitive radio networks( DCRNs).Since the long-term video tra...A novel joint optimization strategy for the secondary user( SU) was proposed to consider the short-term and long-term video transmissions over distributed cognitive radio networks( DCRNs).Since the long-term video transmission consisted of a series of shortterm transmissions, the optimization problem in the video transmission was a composite optimization process. Firstly,considering some factors like primary user's( PU's) collision limitations,non-synchronization between SU and PU,and SU's limited buffer size, the short-term optimization problem was formulated as a mixed integer non-linear program( MINLP) to minimize the block probability of video packets. Secondly,combining the minimum packet block probability obtained in shortterm optimization and SU's constraint on hardware complexity,the partially observable Markov decision process( POMDP) framework was proposed to learn PU's statistic information over DCRNs.Moreover,based on the proposed framework,joint optimization strategy was designed to obtain the minimum packet loss rate in long-term video transmission. Numerical simulation results were provided to demonstrate validity of our strategies.展开更多
Node failure is one of the most severe problems that wireless sensor and actuator networks(WSANs) have to deal with. The failure of actuator nodes, in particular, may result in substantial consequences such as network...Node failure is one of the most severe problems that wireless sensor and actuator networks(WSANs) have to deal with. The failure of actuator nodes, in particular, may result in substantial consequences such as network partitioning, incorrect and incomplete decision execution for WSANs. This paper proposes an efficient localized scheme, called LANTR, to repair the damaged topology of inter-actuator network while single actuator node paralyzes. For the failure of an ordinary actuator node, LANTR can rapidly repair the topology through relocating only one-hop neighbors of the failure node, meanwhile, keep the original topology structure as much as possible. Given the magnitude of cut vertex actuators playing on the connectivity, LANTR designs a novel method for each cut vertex to select out a specific guardian node with the minimum degree or minimum cumulative degree from its neighbors, which can reduce the repair influence on the original topology and effectively reduce the coverage loss rate. The performance of the proposed scheme is evaluated and compared with several existing representative topology repair schemes, and the results indicate that LANTR can more effectively and efficiently repair the topology of inter-actuator networks.展开更多
In this article, a routing protocol EARP (Energy Aware Routing Protocol) with the terminal node is proposed, to deal with the impact of the limited energy resources of Cognitive Radio Networks on the whole network rou...In this article, a routing protocol EARP (Energy Aware Routing Protocol) with the terminal node is proposed, to deal with the impact of the limited energy resources of Cognitive Radio Networks on the whole network routing. The protocol allows choosing the route from the neighbor nodes in different transmission paths, according to energy consumption of a single node and the full path. If the path breaks, the protocol will increase local routing maintenance strategy. It effectively reduces the retransmission caused by the situation, and improves the routing efficiency. It also can prevent the link transmission process selecting the fault route due to the energy depletion. Through simulation experiments compared with the LEACH (Low Energy Adaptive Clustering Hierarchy) routing protocol, the results showed that in the same experimental environment, the proposed EARP could obviously balance the load, protect low energy nodes, prolong the network survival time and reduce packet loss rate and packet delay of data delivery. So it can improve the energy consumption of sensing node and provide routing capabilities.展开更多
This paper analyzes fault-tolerance over the entire design life of a class of multiple-hop wireless networks, where cooperative transmission schemes are used. The networks are subject to both node failure and random c...This paper analyzes fault-tolerance over the entire design life of a class of multiple-hop wireless networks, where cooperative transmission schemes are used. The networks are subject to both node failure and random channel fading. A node lifetime distribution is modeled with an increasing failure rate, where the node power consumption level enters the parameters of the distribution. A method for assessing both link and network reliabilities projected at the network＇s design life is developed. Link reliability is enhanced through use of redundant nodes. The number of redundant nodes is restricted by the cooperative transmission scheme used. The link reliability is then used to establish a re-transmission control policy that minimizes an expected cost involving power, bandwidth expenditures, and packet loss. The benefit and cost of feedback in network operations are examined. The results of a simulation study under specific node processing times are presented. The study quantifies the effect of loop closure frequency, acknowledgment deadline, and nodes＇ storage capacity on the performance of the network in terms of network lifetime, packet loss rate, and false alarm rate. The study concludes that in a network where energy is severely constrained, feedback must be applied judiciously.展开更多
A dynamic network Qo S control mechanism was proposed based on traffic prediction. It first predicts network traffic flow and then dynamically distributes network resources, which makes full use of network flow self-s...A dynamic network Qo S control mechanism was proposed based on traffic prediction. It first predicts network traffic flow and then dynamically distributes network resources, which makes full use of network flow self-similarity and chaos. So it can meet changing network needs very well. The simulation results show that the dynamic Qo S control mechanism based on prediction has better network performance than that based on measurement.展开更多
The Chinese government has raised great attention on water resources and environment over the past several years. In dealing with the issues of water pollution, water management, and the imbalance of water resources, ...The Chinese government has raised great attention on water resources and environment over the past several years. In dealing with the issues of water pollution, water management, and the imbalance of water resources, China’s state council released “Water Pollution Prevention and Control Action Plan” in 2015. This policy has become a guideline to promote water sustainability in the long run. Since then, a number of regulatory policies were released to increase the focus on water conservation. Among those actions, water loss control associated with distribution systems is regarded as a key solution to improve water supply efficiency. This paper provided a comprehensive introduction to the framework of water loss control policy in China.展开更多
基金National Natural Science Foundation of China(No.61301101)
文摘A novel joint optimization strategy for the secondary user( SU) was proposed to consider the short-term and long-term video transmissions over distributed cognitive radio networks( DCRNs).Since the long-term video transmission consisted of a series of shortterm transmissions, the optimization problem in the video transmission was a composite optimization process. Firstly,considering some factors like primary user's( PU's) collision limitations,non-synchronization between SU and PU,and SU's limited buffer size, the short-term optimization problem was formulated as a mixed integer non-linear program( MINLP) to minimize the block probability of video packets. Secondly,combining the minimum packet block probability obtained in shortterm optimization and SU's constraint on hardware complexity,the partially observable Markov decision process( POMDP) framework was proposed to learn PU's statistic information over DCRNs.Moreover,based on the proposed framework,joint optimization strategy was designed to obtain the minimum packet loss rate in long-term video transmission. Numerical simulation results were provided to demonstrate validity of our strategies.
基金supported by the National Natural Science Foundation of China (Grant no. 61662042, 61262081, 61462053, and 61462056)partly supported by the Fundamental Research Funds for the Central Universities (Grant no. ZYGX2012J083)the Applied Fundamental Research Project of Yunnan Province (Grant no. 2014FA028)
文摘Node failure is one of the most severe problems that wireless sensor and actuator networks(WSANs) have to deal with. The failure of actuator nodes, in particular, may result in substantial consequences such as network partitioning, incorrect and incomplete decision execution for WSANs. This paper proposes an efficient localized scheme, called LANTR, to repair the damaged topology of inter-actuator network while single actuator node paralyzes. For the failure of an ordinary actuator node, LANTR can rapidly repair the topology through relocating only one-hop neighbors of the failure node, meanwhile, keep the original topology structure as much as possible. Given the magnitude of cut vertex actuators playing on the connectivity, LANTR designs a novel method for each cut vertex to select out a specific guardian node with the minimum degree or minimum cumulative degree from its neighbors, which can reduce the repair influence on the original topology and effectively reduce the coverage loss rate. The performance of the proposed scheme is evaluated and compared with several existing representative topology repair schemes, and the results indicate that LANTR can more effectively and efficiently repair the topology of inter-actuator networks.
文摘In this article, a routing protocol EARP (Energy Aware Routing Protocol) with the terminal node is proposed, to deal with the impact of the limited energy resources of Cognitive Radio Networks on the whole network routing. The protocol allows choosing the route from the neighbor nodes in different transmission paths, according to energy consumption of a single node and the full path. If the path breaks, the protocol will increase local routing maintenance strategy. It effectively reduces the retransmission caused by the situation, and improves the routing efficiency. It also can prevent the link transmission process selecting the fault route due to the energy depletion. Through simulation experiments compared with the LEACH (Low Energy Adaptive Clustering Hierarchy) routing protocol, the results showed that in the same experimental environment, the proposed EARP could obviously balance the load, protect low energy nodes, prolong the network survival time and reduce packet loss rate and packet delay of data delivery. So it can improve the energy consumption of sensing node and provide routing capabilities.
基金This work was partly supported by the US AFOSR (No. FA9550-06-0456 and FA9550-06-10249).
文摘This paper analyzes fault-tolerance over the entire design life of a class of multiple-hop wireless networks, where cooperative transmission schemes are used. The networks are subject to both node failure and random channel fading. A node lifetime distribution is modeled with an increasing failure rate, where the node power consumption level enters the parameters of the distribution. A method for assessing both link and network reliabilities projected at the network＇s design life is developed. Link reliability is enhanced through use of redundant nodes. The number of redundant nodes is restricted by the cooperative transmission scheme used. The link reliability is then used to establish a re-transmission control policy that minimizes an expected cost involving power, bandwidth expenditures, and packet loss. The benefit and cost of feedback in network operations are examined. The results of a simulation study under specific node processing times are presented. The study quantifies the effect of loop closure frequency, acknowledgment deadline, and nodes＇ storage capacity on the performance of the network in terms of network lifetime, packet loss rate, and false alarm rate. The study concludes that in a network where energy is severely constrained, feedback must be applied judiciously.
基金Funded by the National Natural Science Foundation of China(No.41301084)the Scientific Research Project of Hunan Province Education Department,China(No.13C713)the Natural Science Foundation of Hunan Province,China(No.13JJ6075)
文摘A dynamic network Qo S control mechanism was proposed based on traffic prediction. It first predicts network traffic flow and then dynamically distributes network resources, which makes full use of network flow self-similarity and chaos. So it can meet changing network needs very well. The simulation results show that the dynamic Qo S control mechanism based on prediction has better network performance than that based on measurement.
文摘The Chinese government has raised great attention on water resources and environment over the past several years. In dealing with the issues of water pollution, water management, and the imbalance of water resources, China’s state council released “Water Pollution Prevention and Control Action Plan” in 2015. This policy has become a guideline to promote water sustainability in the long run. Since then, a number of regulatory policies were released to increase the focus on water conservation. Among those actions, water loss control associated with distribution systems is regarded as a key solution to improve water supply efficiency. This paper provided a comprehensive introduction to the framework of water loss control policy in China.
