基于滑窗MCMC的弹道导弹分导团目标数据关联研究

弹道导弹在再入过程中为了提高自身突防能力往往伴随着分导现象。由于分导弹头数目未知,距离目标近且再入速度非常相近,使其以团状形态运动,在未知导弹任何先验信息前提下如何对分导弹头进行快速关联已成为亟待解决的难题。该文提出了一种改进的实时滑窗马尔可夫链-蒙特卡洛(Markov Chain Monte Carlo,MCMC)次优数据关联算法,它应用蒙特卡洛采样方法对监控区域的测量集合进行组合优化,获得最大的后验概率密度进而逼近马氏链的平稳分布。该算法结合弹头分导实际情况,重新分配关联假设权值并优化了继承性,极大地减小了关联时间。仿真结果表明该算法与经典的多假设算法相比,关联概率随着目标密集程度增加而显著提高,并且计算量远小于多假设算法。     

基于有线网络的广电5G集客业务发展机遇分析

本文概述5G时代广电集客业务的发展情况,分析了广电5G 700MHz网络开展集客业务的优势,以及多领域的成功案例,并对广电有线网络公司发挥广电5G优势推动集客业务发展做出了展望.     

Group-Scheduling for Multi-Service Optical Burst Switching (OBS) Networks

We propose a new burst scheduling mechanism for Optical Burst-Switched (OBS) networks. The new approach is made possible by gathering data bursts into groups and performing the scheduling decision for each group collectively. In OBS group-scheduling, bursts will not be considered for scheduling until a pre-defined time period elapses, during which the group of burst header packets would be gathered. By transforming a set of data bursts into a set of corresponding time intervals, the problem of scheduling these bursts is transformed into a combinatorial optimization problem. Graph algorithms are applied to obtain the maximum number of non-overlapping bursts. The proposed OBS group-scheduling scheme is shown to improve the performance of OBS networks over existing scheduling schemes in terms of burst loss probability and channel utilization. With an extension through a sequential optimization, using a Branch-and-Bound technique, the proposed scheme can support multiple classes of service. It is shown that the new scheduling approach has several desired characteristics including fairness and service differentiability among classes in terms of burst loss probability and channel utilization.     

A Novel Refined Track Initiation Algorithm for Group Targets Based on Group Model

Traditional refined track initiation methods for group targets have mistakes or loss of tracks when tracking irregular motions, for the reason that they rely on a stable relative position of group members. To solve the problem, a group dynamic model was introduced for proposing a new initiation algorithm and its whole framework. We made a self-adaptive improvement of the group separation on various group radii. After the pre-association of these groups, a state equation derived from the model was used for predictions of group members. Then a relational matrix was defined for refined data associations. Finally tracks were validated by logic-based method. Particular scenarios and Monte Carlo simulations showed that, compared with algorithms based on relative position, this algorithm has better performance on the adaptability to changes of a group structure and the correctness of initiation.     

新桥DDN网管系统的路由功能

介绍了天津DDN本地网网管系统的路由功能,其中引入了“域”的概念。     

A novel batch-based group key management protocol applied to the Internet of Things

Many applications for ad hoc networks are based on a point-to-multipoint (multicast) communication paradigm, where a single source sends common data to many receivers, or, inversely, on a multipoint-to-point communication paradigm, where multiple sources send data to a single receiver. In such scenarios, communication can be secured by adopting a common secret key, denoted as “group key”, shared by multiple communication endpoints. In this work, we propose a novel centralized approach to efficiently distribute and manage a group key in generic ad hoc networks and Internet of Things, while reducing the computational overhead and network traffic due to group membership changes caused by users’ joins and leaves. In particular, the proposed protocol takes advantage of two possible leave strategies: (i) at a pre-determined time selected when the user joins the group or (ii) at an unpredictable time, as in the case of membership revocation. The proposed protocol is applied to two following relevant scenarios: (i) secure data aggregation in Internet of Things (IoT) and (ii) Vehicle-to-Vehicle (V2V) communications in Vehicular Ad hoc Networks (VANETs).     

针对线性群时延畸变的加权多模盲均衡算法

群时延失真是影响卫星通信系统误码性能的重要因素之一。本文分析了高速卫星信道的线性群时延模型,依此模型提出了改进的加权多模盲均衡算法(MWMMA)。该算法引入Sigmoid函数的变形形式,构造了加权幂指数随迭代误差自适应变化的函数关系,在不需要通过大量仿真实验预先确定模式转变门限值的前提下,利用迭代误差的递减实现算法从MCMA模式通过多模自适应切换为DD模式。通过对多种算法的仿真比较,得到该算法不仅能使通过群时延信道的16QAM信号收敛集中,而且具有更小的稳态剩余码间干扰;同时,基于该算法对64QAM和256QAM传输信号的均衡仿真结果,验证了该算法对高阶QAM信号的均衡具有一定的适用性。      

基于SIP的分布式多方会议系统的安全解决方案

分析并归纳了基于扩展SIP协议的分布式会议系统的安全需求,并且提出了一套可行、有效的安全系统结构和具体解决方案。     

基于图正则化与非负组稀疏的自动图像标注

设计一个稳健的自动图像标注系统的重要环节是提取能够有效描述图像语义的视觉特征。由于颜色、纹理和形状等异构视觉特征在表示特定图像语义时所起作用的重要程度不同且同一类特征之间具有一定的相关性,该文提出了一种图正则化约束下的非负组稀疏(Graph Regularized Non-negative Group Sparsity, GRNGS)模型来实现图像标注,并通过一种非负矩阵分解方法来计算其模型参数。该模型结合了图正则化与l2,1-范数约束,使得标注过程中所选的组群特征能体现一定的视觉相似性和语义相关性。在Corel5K和ESP Game等图像数据集上的实验结果表明：相较于一些最新的图像标注模型,GRNGS模型的鲁棒性更强,标注结果更精确。     

Lazy Group Key Updating Scheme Based on Dynamic Tree

In group key management systems adopting lazy updating, the overhead of key updating might be amortized. In this paper, a Dynamic-tree based Lazy group key updating scheme （DT-LGKU） is presented, which consists of four algorithms Init, Update, Derive and Extract. DT-LGKU supports lazy join events and lazy leave events with unbounded number of time intervals, and provides the forward secrecy and the backward secrecy. DT-LGKU is secure if both the Large Integer Factoring problem and RSA problem are hard. The performance evaluation shows that the worst-case complexity of the cryptographic operations used in the Extract algorithms is logarithmic in the number of time intervals, and those of Init, Update, Derive are constant.