To maintain their capacity,transportation infrastructures are in need of regular maintenance and rehabilitation.The major challenge facing transportation engineers is the network-level policies to maintain the deterio...To maintain their capacity,transportation infrastructures are in need of regular maintenance and rehabilitation.The major challenge facing transportation engineers is the network-level policies to maintain the deteriorating roads at an acceptable level of serviceability.In this work,a quantitative transportation network efficiency measure is presented and then how to determine optimally network-level road maintenance policy depending on the road importance to the network performance has been demonstrated.The examples show that the different roads should be set different maintenance time points in terms of the retention capacities of the roads,because the different roads play different roles in network and have different important degrees to the network performance.This network-level road maintenance optimization method could not only save lots of infrastructure investments,but also ensure the service level of the existing transportation system.展开更多
Radio frequency identification (RFID) is one of today s most anticipated technologies for a broad range of enterprises. Based on the promise of lower operating costs combined with more accurate product and asset infor...Radio frequency identification (RFID) is one of today s most anticipated technologies for a broad range of enterprises. Based on the promise of lower operating costs combined with more accurate product and asset information, organizations .Rfrom manufacturers to government agencies, retailers to healthcare providers , Rare introducing RFID technologies in the supply chain, for asset tracking and management, and for security and regulatory purposes.展开更多
The identification of key nodes plays an important role in improving the robustness of the transportation network.For different types of transportation networks,the effect of the same identification method may be diff...The identification of key nodes plays an important role in improving the robustness of the transportation network.For different types of transportation networks,the effect of the same identification method may be different.It is of practical significance to study the key nodes identification methods corresponding to various types of transportation networks.Based on the knowledge of complex networks,the metro networks and the bus networks are selected as the objects,and the key nodes are identified by the node degree identification method,the neighbor node degree identification method,the weighted k-shell degree neighborhood identification method(KSD),the degree k-shell identification method(DKS),and the degree k-shell neighborhood identification method(DKSN).Take the network efficiency and the largest connected subgraph as the effective indicators.The results show that the KSD identification method that comprehensively considers the elements has the best recognition effect and has certain practical significance.展开更多
In this paper, considering both cluster heads and sensor nodes, we propose a novel evolving a network model based on a random walk to study the fault tolerance decrease of wireless sensor networks (WSNs) due to node...In this paper, considering both cluster heads and sensor nodes, we propose a novel evolving a network model based on a random walk to study the fault tolerance decrease of wireless sensor networks (WSNs) due to node failure, and discuss the spreading dynamic behavior of viruses in the evolution model. A theoretical analysis shows that the WSN generated by such an evolution model not only has a strong fault tolerance, but also can dynamically balance the energy loss of the entire network. It is also found that although the increase of the density of cluster heads in the network reduces the network efficiency, it can effectively inhibit the spread of viruses. In addition, the heterogeneity of the network improves the network efficiency and enhances the virus prevalence. We confirm all the theoretical results with sufficient numerical simulations.展开更多
In this study, the robustness of small-world networks to three types of attack is investigated. Global efficiency is introduced as the network coefficient to measure the robustness of a small-world network. The simula...In this study, the robustness of small-world networks to three types of attack is investigated. Global efficiency is introduced as the network coefficient to measure the robustness of a small-world network. The simulation results prove that an increase in rewiring probability or average degree can enhance the robustness of the small-world network under all three types of attack. The effectiveness of simultaneously increasing both rewiring probability and average degree is also studied, and the combined increase is found to significantly improve the robustness of the small-world network. Furthermore, the combined effect of rewiring probability and average degree on network robustness is shown to be several times greater than that of rewiring probability or average degree individually. This means that small-world networks with a relatively high rewiring probability and average degree have advantages both in network communications and in good robustness to attacks. Therefore, simultaneously increasing rewiring probability and average degree is an effective method of constructing realistic networks. Consequently, the proposed method is useful to construct efficient and robust networks in a realistic scenario.展开更多
Based on lightning location data of lightning monitoring network in Guizhou Province in recent eight years,the effective detection radius of a station and the effective detection range of lightning monitoring network ...Based on lightning location data of lightning monitoring network in Guizhou Province in recent eight years,the effective detection radius of a station and the effective detection range of lightning monitoring network in Guizhou Province were analyzed. The results show that the effective detection radius of a lightning monitoring sub-station in Guizhou Province is 160 km; some counties in the southwest,northwest and northeast of Guizhou were not detected. To improve the detector efficiency of lightning monitoring network in Guizhou Province,it is suggested that nine sub-stations should be built in Weining,Shuicheng,Qinglong,Pingtang,Rongjiang,Yuping,Songtao,Tongren and Renhuai,so that the effective detection efficiency will reach more than 95%.展开更多
In the study of graph convolutional networks,the information aggregation of nodes is important for downstream tasks.However,current graph convolutional networks do not differentiate the importance of different neighbo...In the study of graph convolutional networks,the information aggregation of nodes is important for downstream tasks.However,current graph convolutional networks do not differentiate the importance of different neighboring nodes from the perspective of network topology when ag-gregating messages from neighboring nodes.Therefore,based on network topology,this paper proposes a weighted graph convolutional network based on network node degree and efficiency(W-GCN)model for semi-supervised node classification.To distinguish the importance of nodes,this paper uses the degree and the efficiency of nodes in the network to construct the impor-tance matrix of nodes,rather than the adjacency matrix,which usually is a normalized symmetry Laplacian matrix in graph convolutional network.So that weights of neighbor nodes can be as-signed respectively in the process of graph convolution operation.The proposed method is ex-amined through several real benchmark datasets(Cora,CiteSeer and PubMed)in the experimen-tal part.And compared with the graph convolutional network method.The experimental results show that the W-GCN model proposed in this paper is better than the graph convolutional net-work model in prediction accuracy and achieves better results.展开更多
Surface electromyography(sEMG)is widely used for analyzing and controlling lower limb assisted exoskeleton robots.Behavior intention recognition based on sEMG is of great significance for achieving intelligent prosthe...Surface electromyography(sEMG)is widely used for analyzing and controlling lower limb assisted exoskeleton robots.Behavior intention recognition based on sEMG is of great significance for achieving intelligent prosthetic and exoskeleton control.Achieving highly efficient recognition while improving performance has always been a significant challenge.To address this,we propose an sEMG-based method called Enhanced Residual Gate Network(ERGN)for lower-limb behavioral intention recognition.The proposed network combines an attention mechanism and a hard threshold function,while combining the advantages of residual structure,which maps sEMG of multiple acquisition channels to the lower limb motion states.Firstly,continuous wavelet transform(CWT)is used to extract signals features from the collected sEMG data.Then,a hard threshold function serves as the gate function to enhance signals quality,with an attention mechanism incorporated to improve the ERGN’s performance further.Experimental results demonstrate that the proposed ERGN achieves extremely high accuracy and efficiency,with an average recognition accuracy of 98.41%and an average recognition time of only 20 ms-outperforming the state-of-the-art research significantly.Our research provides support for the application of lower limb assisted exoskeleton robots.展开更多
WiMAX distributed scheduling can be modeled as two procedures:three-way handshaking procedure and data subframe scheduling procedure.Due to manipulating data transmission directly,data subframe scheduling has a close...WiMAX distributed scheduling can be modeled as two procedures:three-way handshaking procedure and data subframe scheduling procedure.Due to manipulating data transmission directly,data subframe scheduling has a closer relationship with user Quality of Service(QoS) satisfaction,and has more severe impact on network performance,compared with handshaking procedure.A QoS guaranteed Throughput-Efficiency Optimal distributed data subframe Scheduling scheme,named as QoS-TEOS,is proposed.QoS-TEOS achieves QoS guarantee through modeling services into different ranks and assigning them with corresponding priorities.A service with higher priority is scheduled ahead of that with lower priority and offered with high QoS quality.Same kinds of services that request similar QoS quality are classified into one service set.Different service sets are scheduled with different strategies.QoS-TEOS promotes network performance through improving network throughput and efficiency.Theoretical analysis shows that the scheduled data transmission should balance data generation rate from upper layer and transmission rate of physical layer,to avoid network throughput and efficiency declining.Simulation results show that QoS-TEOS works excellently to achieve throughput-efficiency optimization and guarantee a high QoS.展开更多
As huge users are involved,there is a difficulty in spectrum allocation and scheduling in Cognitive Radio Networks(CRNs).Collision increases when there is no allocation of spectrum and these results in huge drop rate ...As huge users are involved,there is a difficulty in spectrum allocation and scheduling in Cognitive Radio Networks(CRNs).Collision increases when there is no allocation of spectrum and these results in huge drop rate and network performance degradation.To solve these problems and allocate appropriate spectrum,a novel method is introduced termed as Quality of Service(QoS)Improvement Proper Scheduling(QIPS).The major contribution of the work is to design a new cross layer QoS Aware Scheduling based on Loss-based Proportional Fairness with Multihop(QoSAS-LBPFM).In Medium Access Control(MAC)multi-channel network environment mobile nodes practice concurrent broadcast between several channels.Acquiring the advantage of introduced cross layer design,the real-time channel conditions offered by Cognitive Radio(CR)function allows adaptive sub channel choice for every broadcast.To optimize the resources of network,the LBPFM adaptively plans the radio resources for allocating to diverse services without lessening the quality of service.Results obtained from simulation proved that QoSAS-LBPFM provides enhanced QoS guaranteed performance against other existing QIPS algorithm.展开更多
Building extraction from high resolution remote sensing image is a key technology of digital city construction[14].In order to solve the problems of low efficiency and low precision of traditional remote sensing image...Building extraction from high resolution remote sensing image is a key technology of digital city construction[14].In order to solve the problems of low efficiency and low precision of traditional remote sensing image segmentation,an improved U-Net network structure is adopted in this paper.Firstly,in order to extract efficient building characteristic information,FPN structure was introduced to improve the ability of integrating multi-scale information in U-Net model;Secondly,to solve the problem that feature information weakens with the deepening of network depth,an efficient residual block network is introduced;Finally,In order to better distinguish the target area and background area in the image and improve the precision of building target edge detection,the cross entropy loss and Dice loss were linearly combined and weighted.Experimental results show that the algorithm can improve the image segmentation effect and improve the image accuracy by 18%.展开更多
Cascading failures are common in most of the networks, where traffic is rerouted to bypass malfunctioning routers, eventually leading to an avalanche of overloads on other routers that are not equipped to handle extra...Cascading failures are common in most of the networks, where traffic is rerouted to bypass malfunctioning routers, eventually leading to an avalanche of overloads on other routers that are not equipped to handle extra traffic, which can result in a congestion regime with degradation in the network performance. In order to investigate how a small shock can trigger avalanches mechanisms affecting a considerable fraction of the network, lots of failure models have been constructed, but they have focused only on the static properties of the network that can not reflect the performance affected by the avalanche exactly. In this paper, we proposed a simple model for cascading failures in the network to explore how the failures can have a great impact on the network performance, and we allocated every node a capacity by tolerance parameter based on the node importance, which is determined by node degree, the number of the shortest paths through a node, and the number of the shortest paths through the neighbors of a node, then we fixed every element a weight to compute the node importance by analytic hierarchy process (AHP) theory. Based on our model, we analyzed the influence of different types of attacks to the network performance, and also tabled some proposals for reducing the damage that the networks suffered from the cascading failures.展开更多
The spatial diversity of distributed network demands the individual filter to accommodate the topology of interference environment. In this paper, a type of distributed adaptive beamformer is proposed to mitigate inte...The spatial diversity of distributed network demands the individual filter to accommodate the topology of interference environment. In this paper, a type of distributed adaptive beamformer is proposed to mitigate interference over coordinated antenna arrays network. The proposed approach is formulated as generalized sidelobe canceller (GSC) structure to facilitate the convex combination of neighboring nodes' weights, and then it is solved by unconstrained least mean square (LMS) algorithm due to simplicity. Numerical results show that the robustness and convergence rate of antenna arrays network can be significantly improved in strong interference scenario. And they also clearly illustrate that mixing vector is optimized adaptively and adjusted according to the spatial diversity of the distributed nodes which are placed in different power of received signals to interference ratio (SIR) environments.展开更多
In order to make full use of the radio resource of heterogeneous wireless networks(HWNs) and promote the quality of service(Qo S) of multi-homing users for video communication, a bandwidth allocation algorithm bas...In order to make full use of the radio resource of heterogeneous wireless networks(HWNs) and promote the quality of service(Qo S) of multi-homing users for video communication, a bandwidth allocation algorithm based on multi-radio access is proposed in this paper. The proposed algorithm adopts an improved distributed common radio resource management(DCRRM) model which can reduce the signaling overhead sufficiently. This scheme can be divided into two phases. In the first phase, candidate network set of each user is obtained according to the received signal strength(RSS). And the simple additive weighted(SAW) method is employed to determine the active network set. In the second phase, the utility optimization problem is formulated by linear combining of the video communication satisfaction model, cost model and energy efficiency model. And finding the optimal bandwidth allocation scheme with Lagrange multiplier method and Karush-Kuhn-Tucker(KKT) conditions. Simulation results show that the proposed algorithm promotes the network load performances and guarantees that users obtain the best joint utility under current situation.展开更多
In order to secure the source location privacy when information is sent back to the base station in wireless sensor network, we propose a novel routing strategy which routes the packets to the base station through thr...In order to secure the source location privacy when information is sent back to the base station in wireless sensor network, we propose a novel routing strategy which routes the packets to the base station through three stages: directional random routing, h-hop routing in the annular region and the shortest path routing. These stages provide two fold protections to prevent the source location from being tracked down by the adversary. The analysis and simulation results show that proposed scheme, besides providing longer safety period, can significantly reduce energy consumption compared with two baseline schemes.展开更多
This paper targets on energy saving and considers network responding time for backbone networks. The objective is to find idle links as many as possible which can be put into sleep mode under the situation of quality ...This paper targets on energy saving and considers network responding time for backbone networks. The objective is to find idle links as many as possible which can be put into sleep mode under the situation of quality of service(QoS)-guaranteed. This paper proposes a software defined network(SDN) based routing strategy which is especially aimed at QoS-guaranteed energy saving for backbone networks. Under SDN structure, the topology change of network can be detected directly by network controller. And network can be managed more easily and effectively. Based on the open shortest path first(OSPF) protocol, network topology can be changed as little as possible in our strategy. So, the network reconfiguring time caused by the energy saving strategy will be decreased dramatically. This makes the strategy more feasible. Then the backbone network energy optimizing problem is transformed to the maximum clique problem(MCP). And, this paper designed a routing strategy called backbone networks energy saving strategy(BNESS) for energy saving in backbone networks. Simulation result shows that our proposed strategy can save energy and QoS can be guaranteed.展开更多
Wireless sensor networks(WSNs) are emerging as essential and popular ways of providing pervasive computing environments for various applications. Unbalanced energy consumption is an inherent problem in WSNs, charact...Wireless sensor networks(WSNs) are emerging as essential and popular ways of providing pervasive computing environments for various applications. Unbalanced energy consumption is an inherent problem in WSNs, characterized by multi-hop routing and a many-to-one traffic pattern. This uneven energy dissipation can significantly reduce network lifetime. In multi-hop sensor networks, information obtained by the monitoring nodes need to be routed to the sinks, the energy consumption rate per unit information transmission depends on the choice of the next hop node. In an energy-aware routing approach, most proposed algorithms aim at minimizing the total energy consumption or maximizing network lifetime. In this paper, we propose a novel energy aware hierarchical cluster-based(NEAHC) routing protocol with two goals: minimizing the total energy consumption and ensuring fairness of energy consumption between nodes. We model the relay node choosing problem as a nonlinear programming problem and use the property of convex function to find the optimal solution. We also evaluate the proposed algorithm via simulations at the end of this paper.展开更多
基金Project(71101155)supported by the National Natural Science Foundation of ChinaProject(2015JJ2184)supported by the Natural Science Foundation of Hunan Province,China
文摘To maintain their capacity,transportation infrastructures are in need of regular maintenance and rehabilitation.The major challenge facing transportation engineers is the network-level policies to maintain the deteriorating roads at an acceptable level of serviceability.In this work,a quantitative transportation network efficiency measure is presented and then how to determine optimally network-level road maintenance policy depending on the road importance to the network performance has been demonstrated.The examples show that the different roads should be set different maintenance time points in terms of the retention capacities of the roads,because the different roads play different roles in network and have different important degrees to the network performance.This network-level road maintenance optimization method could not only save lots of infrastructure investments,but also ensure the service level of the existing transportation system.
文摘Radio frequency identification (RFID) is one of today s most anticipated technologies for a broad range of enterprises. Based on the promise of lower operating costs combined with more accurate product and asset information, organizations .Rfrom manufacturers to government agencies, retailers to healthcare providers , Rare introducing RFID technologies in the supply chain, for asset tracking and management, and for security and regulatory purposes.
基金supported by the National Natural Science Foundation of China(Grant No.61961019)the Youth Key Project of the Natural Science Foundation of Jiangxi Province of China(Grant No.20202ACBL212003).
文摘The identification of key nodes plays an important role in improving the robustness of the transportation network.For different types of transportation networks,the effect of the same identification method may be different.It is of practical significance to study the key nodes identification methods corresponding to various types of transportation networks.Based on the knowledge of complex networks,the metro networks and the bus networks are selected as the objects,and the key nodes are identified by the node degree identification method,the neighbor node degree identification method,the weighted k-shell degree neighborhood identification method(KSD),the degree k-shell identification method(DKS),and the degree k-shell neighborhood identification method(DKSN).Take the network efficiency and the largest connected subgraph as the effective indicators.The results show that the KSD identification method that comprehensively considers the elements has the best recognition effect and has certain practical significance.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61103231 and 61103230)the Innovation Program of Graduate Scientific Research in Institution of Higher Education of Jiangsu Province, China (Grant No. CXZZ11 0401)
文摘In this paper, considering both cluster heads and sensor nodes, we propose a novel evolving a network model based on a random walk to study the fault tolerance decrease of wireless sensor networks (WSNs) due to node failure, and discuss the spreading dynamic behavior of viruses in the evolution model. A theoretical analysis shows that the WSN generated by such an evolution model not only has a strong fault tolerance, but also can dynamically balance the energy loss of the entire network. It is also found that although the increase of the density of cluster heads in the network reduces the network efficiency, it can effectively inhibit the spread of viruses. In addition, the heterogeneity of the network improves the network efficiency and enhances the virus prevalence. We confirm all the theoretical results with sufficient numerical simulations.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61101117 and 61171100)the National Key Scientific and Technological Project of China(Grant Nos.2012ZX03004005002 and 2013ZX03003012)+3 种基金the National High Technology Research and Development Program of China(863 Program,Grant No.2014AA01A701)the Special Youth Science Foundation of Jiangxi Province of China(Grant No.20133ACB21007)the Natural Science Foundation of Jiangxi Province of China(Grant Nos.20132BAB201018 and 20132BAB201018)the Fundamental Research Funds for the Central Universities,China(Grant No.BUPT2012RC0112)
文摘In this study, the robustness of small-world networks to three types of attack is investigated. Global efficiency is introduced as the network coefficient to measure the robustness of a small-world network. The simulation results prove that an increase in rewiring probability or average degree can enhance the robustness of the small-world network under all three types of attack. The effectiveness of simultaneously increasing both rewiring probability and average degree is also studied, and the combined increase is found to significantly improve the robustness of the small-world network. Furthermore, the combined effect of rewiring probability and average degree on network robustness is shown to be several times greater than that of rewiring probability or average degree individually. This means that small-world networks with a relatively high rewiring probability and average degree have advantages both in network communications and in good robustness to attacks. Therefore, simultaneously increasing rewiring probability and average degree is an effective method of constructing realistic networks. Consequently, the proposed method is useful to construct efficient and robust networks in a realistic scenario.
基金Supported by the Foundation for Young Scholars of Guizhou Meteorological Bureau,China(QN[2012]13)
文摘Based on lightning location data of lightning monitoring network in Guizhou Province in recent eight years,the effective detection radius of a station and the effective detection range of lightning monitoring network in Guizhou Province were analyzed. The results show that the effective detection radius of a lightning monitoring sub-station in Guizhou Province is 160 km; some counties in the southwest,northwest and northeast of Guizhou were not detected. To improve the detector efficiency of lightning monitoring network in Guizhou Province,it is suggested that nine sub-stations should be built in Weining,Shuicheng,Qinglong,Pingtang,Rongjiang,Yuping,Songtao,Tongren and Renhuai,so that the effective detection efficiency will reach more than 95%.
基金mainly supported by Fundamental Research Program of Shanxi Province(No.202203021211305)Shanxi Scholarship Council of China(2023-013).
文摘In the study of graph convolutional networks,the information aggregation of nodes is important for downstream tasks.However,current graph convolutional networks do not differentiate the importance of different neighboring nodes from the perspective of network topology when ag-gregating messages from neighboring nodes.Therefore,based on network topology,this paper proposes a weighted graph convolutional network based on network node degree and efficiency(W-GCN)model for semi-supervised node classification.To distinguish the importance of nodes,this paper uses the degree and the efficiency of nodes in the network to construct the impor-tance matrix of nodes,rather than the adjacency matrix,which usually is a normalized symmetry Laplacian matrix in graph convolutional network.So that weights of neighbor nodes can be as-signed respectively in the process of graph convolution operation.The proposed method is ex-amined through several real benchmark datasets(Cora,CiteSeer and PubMed)in the experimen-tal part.And compared with the graph convolutional network method.The experimental results show that the W-GCN model proposed in this paper is better than the graph convolutional net-work model in prediction accuracy and achieves better results.
基金The Research and the Development Fund of the Institute of Environmental Friendly Materials and Occupational Health,Anhui University of Science and Technology,Grant/Award Number:ALW2022YF06Academic Support Project for Top-Notch Talents in Disciplines(Majors)of Colleges and Universities in Anhui Province,Grant/Award Number:gxbjZD2021052+1 种基金The University Synergy Innovation Program of Anhui Province,Grant/Award Number:GXXT-2022-053Anhui Province Key R&D Program of China,Grant/Award Number:2022i01020015.
文摘Surface electromyography(sEMG)is widely used for analyzing and controlling lower limb assisted exoskeleton robots.Behavior intention recognition based on sEMG is of great significance for achieving intelligent prosthetic and exoskeleton control.Achieving highly efficient recognition while improving performance has always been a significant challenge.To address this,we propose an sEMG-based method called Enhanced Residual Gate Network(ERGN)for lower-limb behavioral intention recognition.The proposed network combines an attention mechanism and a hard threshold function,while combining the advantages of residual structure,which maps sEMG of multiple acquisition channels to the lower limb motion states.Firstly,continuous wavelet transform(CWT)is used to extract signals features from the collected sEMG data.Then,a hard threshold function serves as the gate function to enhance signals quality,with an attention mechanism incorporated to improve the ERGN’s performance further.Experimental results demonstrate that the proposed ERGN achieves extremely high accuracy and efficiency,with an average recognition accuracy of 98.41%and an average recognition time of only 20 ms-outperforming the state-of-the-art research significantly.Our research provides support for the application of lower limb assisted exoskeleton robots.
基金Supported by Intel Project under Grant No.4507336215Huawei Project under Grant No.YBCB2007025the University of Science and Technology of China Innovation Foundation under Grant No.KD2008053.
文摘WiMAX distributed scheduling can be modeled as two procedures:three-way handshaking procedure and data subframe scheduling procedure.Due to manipulating data transmission directly,data subframe scheduling has a closer relationship with user Quality of Service(QoS) satisfaction,and has more severe impact on network performance,compared with handshaking procedure.A QoS guaranteed Throughput-Efficiency Optimal distributed data subframe Scheduling scheme,named as QoS-TEOS,is proposed.QoS-TEOS achieves QoS guarantee through modeling services into different ranks and assigning them with corresponding priorities.A service with higher priority is scheduled ahead of that with lower priority and offered with high QoS quality.Same kinds of services that request similar QoS quality are classified into one service set.Different service sets are scheduled with different strategies.QoS-TEOS promotes network performance through improving network throughput and efficiency.Theoretical analysis shows that the scheduled data transmission should balance data generation rate from upper layer and transmission rate of physical layer,to avoid network throughput and efficiency declining.Simulation results show that QoS-TEOS works excellently to achieve throughput-efficiency optimization and guarantee a high QoS.
文摘As huge users are involved,there is a difficulty in spectrum allocation and scheduling in Cognitive Radio Networks(CRNs).Collision increases when there is no allocation of spectrum and these results in huge drop rate and network performance degradation.To solve these problems and allocate appropriate spectrum,a novel method is introduced termed as Quality of Service(QoS)Improvement Proper Scheduling(QIPS).The major contribution of the work is to design a new cross layer QoS Aware Scheduling based on Loss-based Proportional Fairness with Multihop(QoSAS-LBPFM).In Medium Access Control(MAC)multi-channel network environment mobile nodes practice concurrent broadcast between several channels.Acquiring the advantage of introduced cross layer design,the real-time channel conditions offered by Cognitive Radio(CR)function allows adaptive sub channel choice for every broadcast.To optimize the resources of network,the LBPFM adaptively plans the radio resources for allocating to diverse services without lessening the quality of service.Results obtained from simulation proved that QoSAS-LBPFM provides enhanced QoS guaranteed performance against other existing QIPS algorithm.
文摘Building extraction from high resolution remote sensing image is a key technology of digital city construction[14].In order to solve the problems of low efficiency and low precision of traditional remote sensing image segmentation,an improved U-Net network structure is adopted in this paper.Firstly,in order to extract efficient building characteristic information,FPN structure was introduced to improve the ability of integrating multi-scale information in U-Net model;Secondly,to solve the problem that feature information weakens with the deepening of network depth,an efficient residual block network is introduced;Finally,In order to better distinguish the target area and background area in the image and improve the precision of building target edge detection,the cross entropy loss and Dice loss were linearly combined and weighted.Experimental results show that the algorithm can improve the image segmentation effect and improve the image accuracy by 18%.
基金supported by a grant from EU FP7 Project EFIPSANS (INFSO-ICT-215549)the Hi-Tech Research and Development program of China (2009ZX003004-001)+1 种基金the Fundament Research Funds for the Central Universities (2009RC0503)Mobility management, control and routing for IMT Advanced and Beyond (2008DFA12110)
文摘Cascading failures are common in most of the networks, where traffic is rerouted to bypass malfunctioning routers, eventually leading to an avalanche of overloads on other routers that are not equipped to handle extra traffic, which can result in a congestion regime with degradation in the network performance. In order to investigate how a small shock can trigger avalanches mechanisms affecting a considerable fraction of the network, lots of failure models have been constructed, but they have focused only on the static properties of the network that can not reflect the performance affected by the avalanche exactly. In this paper, we proposed a simple model for cascading failures in the network to explore how the failures can have a great impact on the network performance, and we allocated every node a capacity by tolerance parameter based on the node importance, which is determined by node degree, the number of the shortest paths through a node, and the number of the shortest paths through the neighbors of a node, then we fixed every element a weight to compute the node importance by analytic hierarchy process (AHP) theory. Based on our model, we analyzed the influence of different types of attacks to the network performance, and also tabled some proposals for reducing the damage that the networks suffered from the cascading failures.
基金supported by National Basic Research Program of China (No. 2010CB731903)
文摘The spatial diversity of distributed network demands the individual filter to accommodate the topology of interference environment. In this paper, a type of distributed adaptive beamformer is proposed to mitigate interference over coordinated antenna arrays network. The proposed approach is formulated as generalized sidelobe canceller (GSC) structure to facilitate the convex combination of neighboring nodes' weights, and then it is solved by unconstrained least mean square (LMS) algorithm due to simplicity. Numerical results show that the robustness and convergence rate of antenna arrays network can be significantly improved in strong interference scenario. And they also clearly illustrate that mixing vector is optimized adaptively and adjusted according to the spatial diversity of the distributed nodes which are placed in different power of received signals to interference ratio (SIR) environments.
基金supported by the National Natural Science Foundation of China (61571234, 61401225)the National Basic Research Program of China (2013CB329005)+1 种基金the Hi-Tech Research and Development Program of China (2014AA01A705)the Graduate Student Innovation Plan of Jiangsu Province (SJLX15_0365)
文摘In order to make full use of the radio resource of heterogeneous wireless networks(HWNs) and promote the quality of service(Qo S) of multi-homing users for video communication, a bandwidth allocation algorithm based on multi-radio access is proposed in this paper. The proposed algorithm adopts an improved distributed common radio resource management(DCRRM) model which can reduce the signaling overhead sufficiently. This scheme can be divided into two phases. In the first phase, candidate network set of each user is obtained according to the received signal strength(RSS). And the simple additive weighted(SAW) method is employed to determine the active network set. In the second phase, the utility optimization problem is formulated by linear combining of the video communication satisfaction model, cost model and energy efficiency model. And finding the optimal bandwidth allocation scheme with Lagrange multiplier method and Karush-Kuhn-Tucker(KKT) conditions. Simulation results show that the proposed algorithm promotes the network load performances and guarantees that users obtain the best joint utility under current situation.
基金Supported by the National Natural Science Foundation of China(61170065)the Natural Science Foundation of Jiangsu Province(BK20130882)the Scientific Research Foundation of Nanjing University of Posts and Telecommunications(NY214118)
文摘In order to secure the source location privacy when information is sent back to the base station in wireless sensor network, we propose a novel routing strategy which routes the packets to the base station through three stages: directional random routing, h-hop routing in the annular region and the shortest path routing. These stages provide two fold protections to prevent the source location from being tracked down by the adversary. The analysis and simulation results show that proposed scheme, besides providing longer safety period, can significantly reduce energy consumption compared with two baseline schemes.
基金supported by the National High-Tech R&D Program(2015AA01A705)Beijing Municipal Commission of Education(The city’s vehicle sensing grid construction based on public transportation network)
文摘This paper targets on energy saving and considers network responding time for backbone networks. The objective is to find idle links as many as possible which can be put into sleep mode under the situation of quality of service(QoS)-guaranteed. This paper proposes a software defined network(SDN) based routing strategy which is especially aimed at QoS-guaranteed energy saving for backbone networks. Under SDN structure, the topology change of network can be detected directly by network controller. And network can be managed more easily and effectively. Based on the open shortest path first(OSPF) protocol, network topology can be changed as little as possible in our strategy. So, the network reconfiguring time caused by the energy saving strategy will be decreased dramatically. This makes the strategy more feasible. Then the backbone network energy optimizing problem is transformed to the maximum clique problem(MCP). And, this paper designed a routing strategy called backbone networks energy saving strategy(BNESS) for energy saving in backbone networks. Simulation result shows that our proposed strategy can save energy and QoS can be guaranteed.
基金supported by the National Youth Science Fund Project(61501052,61501047)the Fundamental Research Funds for the Central Universities of China(2015RC05)
文摘Wireless sensor networks(WSNs) are emerging as essential and popular ways of providing pervasive computing environments for various applications. Unbalanced energy consumption is an inherent problem in WSNs, characterized by multi-hop routing and a many-to-one traffic pattern. This uneven energy dissipation can significantly reduce network lifetime. In multi-hop sensor networks, information obtained by the monitoring nodes need to be routed to the sinks, the energy consumption rate per unit information transmission depends on the choice of the next hop node. In an energy-aware routing approach, most proposed algorithms aim at minimizing the total energy consumption or maximizing network lifetime. In this paper, we propose a novel energy aware hierarchical cluster-based(NEAHC) routing protocol with two goals: minimizing the total energy consumption and ensuring fairness of energy consumption between nodes. We model the relay node choosing problem as a nonlinear programming problem and use the property of convex function to find the optimal solution. We also evaluate the proposed algorithm via simulations at the end of this paper.