对地攻击协同制导决策方法

在多机协同对地攻击作战中,针对需要将空地导弹的人在回路制导权移交给其他飞机的问题,建立了协同制导决策模型.在分析了协同制导交接过程、协同制导交接条件、协同制导交接方式的基础上,提出了制导优势概念,用来表征编队内其他飞机对导弹协同制导的能力;然后,在考虑协同制导交接环境条件和人为因素的基础上,建立协同制导决策模型,从而为...     

协同编辑中的迟加入问题和协作可靠性

实时协同编辑中协作站点在不同时机加入时,由于网络延时或故障会导致其初始状态的不一致,即同步问题.同时,协作过程中站点或网络故障或长时间无操作生成,以及会话管理器的容错等问题会影响系统可靠性.本文提出一个多迟加入server算法,解决了迟加入client初始状态的一致性;提出一种基于会话管理器的站点查询算法和分布式备份模型,保证系统可靠协作.通过实例对相关算法的有效性进行了验证.     

未来无线系统中的协作通信

协作通信作为一种新型的通信模式越来越受到人们的关注,它通过不同网络元素之间的相互合作来达到网络资源的共享,进而提高传输可靠性和系统吞吐量,有效改善用户的服务质量。     

多机协同多目标攻击空战战术决策

以多机协同攻击多个目标为研究背景,提出一种目标分配的决策分析方法。首先建立攻击过程中的优势模型和目标威胁模型,根据该模型分析多目标攻击过程中我方的优势和目标威胁度,然后将该优势与威胁度相加权,由此得到多目标攻击决策准则。示例表明,该方法能够根据空战态势合理地决策好所要攻击的目标,并为航空火控系统实现多目标攻击提供准确依据。     

Cooperative Regions and Partner Choice in Coded Cooperative Systems

User cooperation is an efficient approach to obtain diversity in both centralized and distributed wireless networks. In this paper, we consider a coded cooperative system under quasi-static Rayleigh fading and investigate the partner-choice problem. We find conditions on the interuser and user-to-destination channel qualities for cooperation to be beneficial. Using frame-error rate (FER) as a metric, we define the user cooperation gain (G) for evaluating the relative performance improvement of cooperative over direct transmissions when a particular channel code is used. We introduce the cooperation decision parameter (CDP), which is a function of user-to-destination average received signal-to-noise ratios (SNRs), and demonstrate that whether cooperation is useful or not ($G≫1$or$G≪1$) depends only on the CDP, not the interuser link quality. We use an analytical formulation of the CDP to investigate user cooperation gain and provide insights on how a user can choose among possible partners to maximize cooperation gain. We first consider the asymptotic performance when one or both partners have high average received SNR at the destination. We then provide conditions on user and destination locations for cooperation to be beneficial for arbitrary SNRs. We illustrate these cooperative regions and study geometric conditions for the best partner choice. We also define the system cooperation gain and illustrate cooperation benefit for both users. All of our theoretical results are verified through numerical examples.     

Relay Selection in Two-Way Cooperative Systems

In this paper, we present a design of two-way communication system with relay selection in two-way cooperative system over cascaded Nakagami- \(m\) fading channels. In the proposed scheme, in which all terminals are in motion as mobiles or vehicles, two users first broadcast their information to relays. Then, a single relay with a minimum sum symbol error rate (SER) will be selected to broadcast the received signals back to the sources. In other words, in the selection process, we investigate a simple suboptimal min-max criterion for relay selection, where a single relay that minimizes the maximum SER of two source nodes will be selected. Specifically, we have derived expressions of cumulative distribution function and moment generating function of end-to-end signal-to-noise ratio. By using these expressions, we have analyzed the performance of considered system in terms of outage probability and SER expression. Numerical and simulation results show the validity of the proposed mathematical analysis and point out the confirmation of the analytical results.     

Rumor Riding: An Anonymity Approach for Decentralized Peer to Peer Systems

The anonymizing peer to peer (P2P) system is frequently incurred additional expense in order to efficiency transfer and various systems execute to disguise the uniqueness privacy considerations issues for their users. Although, an anonymity technique mostly existing path base peer before transmits, it has pre-create an anonymous path. An information as well as maintenance transparency of path is a lot high. In this paper it has been proposed mutual anonymity rumor riding (RR) protocol for decentralization environment P2P systems. The very heavy load path construction carries by RR system using random walk mechanism for free initiate peers. We evaluate with before RSA based and also anonymity approach based on AES, RR get extra benefit of lower cryptographic overhead mostly to get anonymity using asymmetric cryptographic algorithm. We illustrate design and effectiveness during the simulations by trace driven. RR is very effect and efficient than previous protocols the experimental and analytical result shows us.     

多级影响图在无人机群协同空战机动决策中的应用

现代空战多为机群对机群的空战。针对无人机群空战中协同攻防机动决策的问题,首先提出了针对单机对单机的在不确定环境下基于多级影响图的空战决策建模。在此基础上对无人机群进行分组,并根据无人机的空战能力划分角色,在空战初始确定小组内的长机与僚机。通过引入协同因子,对空战机动决策中的当前局势概率重新进行加权修正,很好地解决了单元内各成员协同配合的问题,从而将单纯的一对一空战引申为多机对多机协同空战。仿真结果表明所建立的决策模型能够有效地解决无人机群协同空战的机动决策问题。     

Cooperative Coding for OFDM Systems

In this paper, we study Orthogonal Frequency Division Multiplexing (OFDM) systems with cooperative coding over frequency selective Rayleigh fading channels. We derive the pairwise error probability (PEP) for the block-fading OFDM channel model. We use the derived PEP to get an upper bound on the frame error probability for the coded cooperative OFDM system. This bound is then utilized in the study of the diversity and coding gains achievable through cooperative coding in OFDM systems for various inter-user channel qualities. We consider the design of cooperative convolutional codes based on the principle of overlays and provide simulation results for different cooperation scenarios. We observe significant gains over conventional non-cooperative OFDM systems. Finally, based on some simple approximations, we provide guidelines for the choice of partners in coded cooperative OFDM systems.     

最佳中继协作通信系统的功率分配算法

 为提高基于最佳中继选择的协作通信系统的性能,提出了以最小化系统中断概率为目标的功率分配算法.首先建立了系统的优化模型并证明了待解的优化问题实质是凸优化问题,由此提出了最优功率分配算法并给出了算法步骤.其次,在此基础上提出了一种有效的次最优功率分配算法,该算法计算简单且仅需已知各个中继节点的平均信道状态信息,无需在传输中实时更新,因而不增加系统的额外开销.仿真结果表明,本文提出的最优算法和次最优算法所得到的功率分配方案与穷举搜索方法的结果非常接近;与等功率分配方案相比,这两种算法均能显著提高系统的中断概率性能.     

A Decentralized Model Reference Adaptive Controller for Large-Scale Systems

A decentralized model reference adaptive controller (MRAC) for a class of large-scale systems with unmatched interconnections is developed in this paper. A novel reference model is proposed for the class of large-scale systems considered and a decentralized, full-state feedback adaptive controller is developed for each subsystem of the large-scale system. It is shown that with the proposed decentralized adaptive controller, the states of the subsystems can asymptotically track the desired reference trajectories. To substantiate the performance of the proposed controller, a large web processing line, which mimics most of the features of an industrial web process line, is considered for experimental study. Extensive experiments were conducted with the proposed decentralized adaptive controller and an often used decentralized industrial proportional-integral (PI) controller. A representative sample of the comparative experimental results is shown and discussed     

机会协同通信系统的中继公平性研究

为提高机会协同通信系统的中继选择公平性,提出了以不影响系统中断性能为目标的协同方案。在建立了协同通信系统模型的基础上,提出机会协同方案,并引入比例公平算法对机会协同方案进行改进;分别对2种方案下的中继选择概率与系统中断概率进行了分析,根据定义的公平因子表征中继公平性与理想公平上限。仿真结果表明,提出的基于比例公平的机会协同方案,显著改善了中继选择的公平性,在大信噪比条件下趋近理想公平上限,同时保持了系统中断性能。     

基于认知的协作系统中继分配算法

随着无线移动通信系统的飞速发展,无线通信网络能耗急剧增加,基于中继协作技术的绿色无线通信研究受到众多研究者的关注.针对基于认知的中继协作系统,提出了一种以最大主系统能效为目标的中继分配算法.该算法在不影响主系统性能基础上,对主系统请求次系统用户作为中继转发数据,且共享主用户频谱进行了简要介绍.算法中次系统通过最大权重匹配方法为主系统分配中继（次用户）,在满足主系统能效最大化的同时,实现了次系统与主系统的频谱共享.对算法进行仿真验证,提出的算法能获得较高的主系统能效,同时提高了整个系统的频谱利用率.     

Timing Synchronization in Decode-and-Forward Cooperative Communication Systems

Cooperative communication systems have attracted much attention recently due to their desirable performance gain while using single antenna terminals. This paper addresses the joint timing and channel estimation problem, and furthermore the resynchronization of multiple timing offsets in a cooperative relay system. The estimations of timing and channel are conducted in two phases and the associated CramÉr-Rao bounds (CRB) are derived for both phases. It is demonstrated that the conventional CRB is not valid for timing parameters under fading conditions, and a new bound called Weighted Bayesian CRB is proposed. With the timing and channel estimates, a general framework of the resynchronization filter design is developed in order to compensate the multiple timing offsets at the destination. The proposed methods are applied to different scenarios with varying degrees of timing misalignment and are numerically shown to provide excellent performances that approach the perfectly synchronized case.      

Power-Minimizing Rate Allocation in Cooperative Uplink Systems

The rate-allocation problem, which has been aimed at minimizing the total transmit power in cooperative uplink systems, is investigated. Each user transmits over an orthogonal frequency band using cooperative broadcasting. The broadcasting nature of the wireless channel is exploited by allowing users to act as relays for one another. All users operate in the decode-and-forward mode. Depending on the number of relays that was selected by a user, we suggest two schemes: 1) the flow-optimized cooperative scheme (FCS) and 2) the single-relay cooperative scheme (SCS). We develop rate-allocation algorithms for them. In our simulation, we compare the outage performance of our schemes with two other schemes: 1) the orthogonal cooperative scheme and 2) direct transmission. Results indicate that our schemes achieve full diversity order and outperform other compared schemes. The algorithm for FCS achieves the optimality, whereas the algorithm for SCS is near optimal. In addition, our algorithms have fast convergence performance. SCS has a lower complexity than FCS, but it requires a higher total transmit power. However, the difference in total transmit power between FCS and SCS is not large under practical rate requirements. In addition to the total transmit power, we consider the improvement in the individual transmit powers of the users.      

基于LMI的时滞模糊大系统的分散镇定

讨论了具有时滞关联的模糊大系统的分散镇定问题，基于李亚普诺夫稳定性理论及大系统分散控制理论，给出了保证该时滞模糊大系统闭环渐近稳定的LMI形式的充分条件。满足这些充分条件的分散化并行分布补偿(DPDC)控制器参数可通过MATLAB的LMI工具箱有效地求取。因此本文提供了一个综合时滞关联模糊大系统DPDC模糊控制器的有效方法。     

通信对抗系统配置时的辅助决策

主要根据通信对抗系统的战斗配置要求,归纳了对通信对抗系统配置进行辅助决策时应遵循的规则,最后介绍通信对抗系统配置时辅助决策的流程。     

Decentralized Optimal Fusion Filtering for Multi-Sensor Multi-Delay Singular Systems

The optimal fusion problem for the state estimation of discrete-time multi-sensor multi-delay stochastic singular systems is considered. The key idea is to convert a multi-sensor stochastic singular system into a group of nonsingular systems. Applying projection theory, the state estimation and estimating error variance for each local nonsingular subsystem are derived. After obtaining the estimating error cross-covariance between local subsystems, and using the optimal fusion algorithm in the linear minimum variance sense, a fusion filter for the original singular system is derived. A simulation example shows that the fusion filter is better than each local filter.     

Improved Policy for Resource Allocation in Decentralized Dynamic Spectrum Sharing Systems

In this letter, resource allocation in decentralized spectrum sharing systems applying the existing policy rule referred to as ?inequality-averse policy? is focused on. The problem related to the impact of inaccurate estimation of future traffic demands on the performance of such systems is addressed. To alleviate the problem, improved policy, which introduces adjusting factors and is resistant to such estimation errors, is proposed.     

An Enhanced Decision-Making Fault Detection Model in Medical IoT Embedded Systems

Wireless Personal Communications - In the Internet of Things (IoT) embedded systems, error-detecting code methods are used to predict fault detection in a data block. Applying an error-detecting...