Advanced traveler information systems （ATIS） can not only improve drivers＇ accessibility to the more accurate route travel time information, but also can improve drivers＇ adaptability to the stochastic network cap...Advanced traveler information systems （ATIS） can not only improve drivers＇ accessibility to the more accurate route travel time information, but also can improve drivers＇ adaptability to the stochastic network capacity degradations. In this paper, a mixed stochastic user equilibrium model was proposed to describe the interactive route choice behaviors between ATIS equipped and unequipped drivers on a degradable transport network. In the proposed model the information accessibility of equipped drivers was reflected by lower degree of uncertainty in their stochastic equilibrium flow distributions, and their behavioral adaptability was captured by multiple equilibrium behaviors over the stochastic network state set. The mixed equilibrium model was formulated as a fixed point problem defined in the mixed route flows, and its solution was achieved by executing an iterative algorithm. Numerical experiments were provided to verify the properties of the mixed network equilibrium model and the efficiency of the iterative algorithm.展开更多
For the problem of large network load generated by the Gnutella resource-searching model in Peer to Peer （P2P） network, a improved model to decrease the network expense is proposed, which establishes a duster in P2P...For the problem of large network load generated by the Gnutella resource-searching model in Peer to Peer （P2P） network, a improved model to decrease the network expense is proposed, which establishes a duster in P2P network, auto-organizes logical layers, and applies a hybrid mechanism of directional searching and flooding. The performance analysis and simulation results show that the proposed hierarchical searching model has availably reduced the generated message load and that its searching-response time performance is as fairly good as that of the Gnutella model.展开更多
In the past decade,the e-government affairs keep developing,which prom otes the reform of governmental affairs and the enhancement of administrative efficiency.However,the phenomenon of inform ation silo has bad influ...In the past decade,the e-government affairs keep developing,which prom otes the reform of governmental affairs and the enhancement of administrative efficiency.However,the phenomenon of inform ation silo has bad influence upon the governm ental information resources sharing and the efficiency of the e-government affairs,hindering inform ation connectivity,so that the government management cannot meet the need of society,nor can the e-governm ent develop in the long run.This paper attempts to analyze the embodiment and causes of the phenomenon of information silo,putting forward measures of solving the problem of inform ation silo.展开更多
跨域推荐技术通过深入挖掘及利用其他域的有用信息,有效提升目标域的推荐表现,为解决用户冷启动问题提供了一种有效途径。然而,当前跨域推荐方法存在局限,未能细粒度地扩展隐式关系,并且忽视了嵌入向量中可能包含的冗余信息,从而制约了...跨域推荐技术通过深入挖掘及利用其他域的有用信息,有效提升目标域的推荐表现,为解决用户冷启动问题提供了一种有效途径。然而,当前跨域推荐方法存在局限,未能细粒度地扩展隐式关系,并且忽视了嵌入向量中可能包含的冗余信息,从而制约了跨域推荐系统的性能。鉴于此,提出一种基于域内和域间元路径聚合的跨域推荐方法,IMCDR(intra-domain and inter-domain meta-paths aggregation based cross-domain recommendation)。IMCDR首先通过细粒度地计算实体多字段的语义嵌入,有效扩展用户-用户和物品-物品关系;然后,IMCDR基于域内元路径和域间元路径为每个节点分别生成私有特征和共享特征,并将它们有效融合,以获得更高质量的嵌入向量。在三个跨域推荐任务上的综合实验结果表明,IMCDR在有效性和性能上具有明显优势。展开更多
在资源受限的水声网络中,使用软频率复用技术和自适应资源分配技术可以提高网络容量和能量效率。然而,水声信道的长传播时延和时变特性导致用于自适应技术的反馈信道状态信息(Channel State Information, CSI)是时变且过时的。非理想的...在资源受限的水声网络中,使用软频率复用技术和自适应资源分配技术可以提高网络容量和能量效率。然而,水声信道的长传播时延和时变特性导致用于自适应技术的反馈信道状态信息(Channel State Information, CSI)是时变且过时的。非理想的反馈CSI会降低自适应系统的性能。针对该问题,提出了一种基于多智能体深度Q网络的资源分配(Multi-agent Deep Q Network Based Resource Allocation, MADQN-RA)方法。该方法将水声软频率复用网络视为多智能体系统,并使用过时的反馈CSI序列作为系统状态。通过建立有效的奖励表达式,智能体可以跟踪时变时延水声信道的变化特性并做出相应的资源分配决策。为了进一步提高智能体的决策准确度,同时避免状态空间维度增大时的部分学习成本,结合动态状态长度方法改进了MADQN-RA。仿真结果表明,所提方法实现的系统性能优于基于其他学习的方法和基于信道预测的方法,且更接近理论最优值。展开更多
针对认知无线电-非正交多址接入系统开放性带来的通信安全问题,提出一种基于DC(difference of convex)规划的CR-NOMA系统物理层安全方案.在非正交多址(non-orthogonal multiple access,NOMA)通信场景下,构建多用户窃听信道模型,推导出CR...针对认知无线电-非正交多址接入系统开放性带来的通信安全问题,提出一种基于DC(difference of convex)规划的CR-NOMA系统物理层安全方案.在非正交多址(non-orthogonal multiple access,NOMA)通信场景下,构建多用户窃听信道模型,推导出CR-NOMA系统的安全和速率表达式;并设计基于DC的载波功率分配算法,求解子信道功率分配的最优解,提高系统子载波的安全性.仿真结果表明,在不增加基站功率情况下,其安全和速率较OFDMA和NOMA分别提升了35%和10%;在相同安全和速率下,用户数量最大可增加200%.验证了该方案能够有效提升系统物理层安全.展开更多
基金Projects(51378119,51578150)supported by the National Natural Science Foundation of China
文摘Advanced traveler information systems （ATIS） can not only improve drivers＇ accessibility to the more accurate route travel time information, but also can improve drivers＇ adaptability to the stochastic network capacity degradations. In this paper, a mixed stochastic user equilibrium model was proposed to describe the interactive route choice behaviors between ATIS equipped and unequipped drivers on a degradable transport network. In the proposed model the information accessibility of equipped drivers was reflected by lower degree of uncertainty in their stochastic equilibrium flow distributions, and their behavioral adaptability was captured by multiple equilibrium behaviors over the stochastic network state set. The mixed equilibrium model was formulated as a fixed point problem defined in the mixed route flows, and its solution was achieved by executing an iterative algorithm. Numerical experiments were provided to verify the properties of the mixed network equilibrium model and the efficiency of the iterative algorithm.
文摘For the problem of large network load generated by the Gnutella resource-searching model in Peer to Peer （P2P） network, a improved model to decrease the network expense is proposed, which establishes a duster in P2P network, auto-organizes logical layers, and applies a hybrid mechanism of directional searching and flooding. The performance analysis and simulation results show that the proposed hierarchical searching model has availably reduced the generated message load and that its searching-response time performance is as fairly good as that of the Gnutella model.
文摘In the past decade,the e-government affairs keep developing,which prom otes the reform of governmental affairs and the enhancement of administrative efficiency.However,the phenomenon of inform ation silo has bad influence upon the governm ental information resources sharing and the efficiency of the e-government affairs,hindering inform ation connectivity,so that the government management cannot meet the need of society,nor can the e-governm ent develop in the long run.This paper attempts to analyze the embodiment and causes of the phenomenon of information silo,putting forward measures of solving the problem of inform ation silo.
文摘跨域推荐技术通过深入挖掘及利用其他域的有用信息,有效提升目标域的推荐表现,为解决用户冷启动问题提供了一种有效途径。然而,当前跨域推荐方法存在局限,未能细粒度地扩展隐式关系,并且忽视了嵌入向量中可能包含的冗余信息,从而制约了跨域推荐系统的性能。鉴于此,提出一种基于域内和域间元路径聚合的跨域推荐方法,IMCDR(intra-domain and inter-domain meta-paths aggregation based cross-domain recommendation)。IMCDR首先通过细粒度地计算实体多字段的语义嵌入,有效扩展用户-用户和物品-物品关系;然后,IMCDR基于域内元路径和域间元路径为每个节点分别生成私有特征和共享特征,并将它们有效融合,以获得更高质量的嵌入向量。在三个跨域推荐任务上的综合实验结果表明,IMCDR在有效性和性能上具有明显优势。
文摘在资源受限的水声网络中,使用软频率复用技术和自适应资源分配技术可以提高网络容量和能量效率。然而,水声信道的长传播时延和时变特性导致用于自适应技术的反馈信道状态信息(Channel State Information, CSI)是时变且过时的。非理想的反馈CSI会降低自适应系统的性能。针对该问题,提出了一种基于多智能体深度Q网络的资源分配(Multi-agent Deep Q Network Based Resource Allocation, MADQN-RA)方法。该方法将水声软频率复用网络视为多智能体系统,并使用过时的反馈CSI序列作为系统状态。通过建立有效的奖励表达式,智能体可以跟踪时变时延水声信道的变化特性并做出相应的资源分配决策。为了进一步提高智能体的决策准确度,同时避免状态空间维度增大时的部分学习成本,结合动态状态长度方法改进了MADQN-RA。仿真结果表明,所提方法实现的系统性能优于基于其他学习的方法和基于信道预测的方法,且更接近理论最优值。
文摘针对认知无线电-非正交多址接入系统开放性带来的通信安全问题,提出一种基于DC(difference of convex)规划的CR-NOMA系统物理层安全方案.在非正交多址(non-orthogonal multiple access,NOMA)通信场景下,构建多用户窃听信道模型,推导出CR-NOMA系统的安全和速率表达式;并设计基于DC的载波功率分配算法,求解子信道功率分配的最优解,提高系统子载波的安全性.仿真结果表明,在不增加基站功率情况下,其安全和速率较OFDMA和NOMA分别提升了35%和10%;在相同安全和速率下,用户数量最大可增加200%.验证了该方案能够有效提升系统物理层安全.
