基于动态优先级的相控阵雷达自适应调度

相控阵雷达需要在完成作战空域搜索的同时完成多个目标捕获以及精确跟踪。为了能够及时有效、充分地调度安排雷达时间资源,本文提出了基于动态优先级的雷达自适应调度模型,根据雷达事件调度时间窗偏移及其需求时间片与离散时间片的契合对优先级进行动态调整和排序,完成雷达事件自适应调度,并给出了相控阵雷达应用实例。与基于固定优先级的雷达自适应调度模型相比较,该模型能够提高雷达波束调度成功率和时间资源利用率。     

基于价值密度的相控阵雷达事件调度算法

针对相控阵雷达事件调度问题中求解目标综合优先级时未考虑事件驻留时间的问题,提出一种基于“价值密度”的相控阵雷达事件调度算法。通过引入作业车间调度领域“价值密度”概念,根据目标属性、运动状态、雷达硬件条件、事件截止期等参数,共同计算雷达完成该事件时单位时间内所能具有的价值,即该事件的价值密度;并基于价值密度进行调度。仿真实验表明,基于价值密度的调度算法与传统基于综合优先级排序调度算法相比,能有效提高调度成功率和实现价值率。     

车联网中交通安全消息动态优先调度机制

车联网中两类交通安全消息共享有限控制信道带宽,在消息突发状态下无法保证事件触发消息的传播性能,导致预警失效.基于差异化的消息传播性能需求提出了一种动态优先级区分的调度机制,按事件优先级分别进行队列管理,赋予事件触发消息优先权,通过设置优先级调度阈值实现对事件触发消息的动态调度.当优先队列长度高于阈值时,其抢占调度时隙.当队列长度低于阈值一半,退出抢占过程,恢复非抢占优先调度方法.仿真显示,所提调度机制能够减小事件触发消息的端到端时延约1.3 ms,提高周期性消息的公平性约0.22.     

基于流水线的优先级队列排序的VLSI实现

优先级队列排序是众多队列调度算法硬件实现的主要瓶颈。文章提出了一种基于流水线的优先级队列的硬件快速排序结构。该结构具有O（1）的时间复杂度，支持上万个优先级队列，满足OC-192甚至更高网络传输速率的要求。     

远程预警相控阵雷达资源调度仿真研究

在分析远程预警雷达工作方式和资源调度设计原则的基础上，提出了一种仿真实现自适应资源调度的方法，并给出了仿真实现的详细流程。该方法能够根据雷达事件的优先级、驻留长度以及期望发射时间合理的安排雷达事件，仿真结果验证了该方法的有效性。     

基于模糊聚类的机载多功能毫米波雷达动态资源调度

详细介绍武装直升机载多功能雷达的工作环境和资源管理所面临的挑战.在深入分析雷达资源管理特点和影响资源调度算法的主要因素基础上,提出一种基于模糊聚类的自适应雷达资源动态调度算法.详细分析了跟踪事件和搜索事件的优先级模糊特征因子,给出合理的动态优先级模糊聚类数学模型.结果表明,基于模糊优先级聚类的动态资源管理算法在密集目标...     

多功能相控阵雷达自适应调度算法研究

由于阵列天线的波束捷变能力 ,多功能相控阵雷达可对多个目标交替进行搜索、验证、跟踪等工作方式的操作。为此 ,需要一种调度策略以有效地分配雷达时间和能量等资源 ,达到优化雷达整体性能的目的。针对多功能相控阵雷达 ,在分析自适应调度算法的设计原则基础上提出一种自适应调度算法 ,并给出具体的性能评估指标。算法能够根据雷达事件的优先级、驻留长度、期望发射时间及时间窗合理地安排一个调度间隔内的雷达事件序列 ,仿真结果验证了调度算法的有效性。     

基于平衡二叉树的优先级队列管理

随着网络的发展,网络流量越来越大,拥塞问题越来越严重,各种队列管理算法应运而生,然而这些算法在丢弃数据包时却忽略了数据包的优先级或对优先级队列的处理不够完善。文章先介绍了优先级队列以及一些优先级队列的管理办法,然后提出利用平衡二叉树这种数据结构实现对优先级队列的入队列和出队列操作,最后提出一种对RED(随机提前探测)算法的改进方案。     

基于弹簧振子模型的雷达事件调度方法

相控阵雷达与常规机械扫描雷达相比,其对空中目标的探测更加灵活、快速,能够在微秒量级形成定位的雷达波束,先进事件调度方式是发挥这一优势的关键所在。对于固定调度间隔和优先级调度算法,级别较高的事件抢占位置后不再调整,对于冲突的同等级别或级别低的事件进行时间窗内调整。其优点就是运算简单,无需反复调整,同时也产生较多破碎的时间片段,对于平均时间偏移率也无法实现优化调整,浪费雷达有限的资源。本文将弹簧振子模型引入到雷达事件调度算法中,利用弹簧双向调整原理,在最小能量的约束下,实现对雷达申请事件有反馈地自适应调度。结合对弹簧振子固有参数的设计可以在计算量与评价指标之间进行取舍,增加了算法可设计的空间。     

相控阵雷达自适应调度算法仿真

灵活、高效的调度算法是相控阵雷达发挥其性能优势的关键,而如何分配任务优先级对雷达性能有着决定性的影响。文章将BP神经网络引入调度算法,利用目标运动参数和跟踪状态实时自适应地分配任务优先级。算法根据优先级和时间约束,合理安排调度周期内雷达任务请求,选择优先级较高的那部分雷达任务执行,并通过仿真结果验证了算法的有效性。     

Approximate analysis of timer-controlled priority scheme in thesingle-service token-passing systems

This paper presents an approximate analysis of delay performance in the timer-controlled priority scheme of single-service token passing systems, where each priority queue is allowed to transmit one message at a time. This is the practical case of real-time networks such as those used in aircraft and spacecraft control, process control and factory communications. The token passing systems consist of N stations, each of which has (K+1) priority queues. The highest priority queues can transmit a message whenever the token arrives. A lower priority queue can transmit a message if the token rotation time (which was reset and restarted at the previous token arrival instant) is not expired when the token arrives. An analytical model is developed based on the independent and identically distributed random variables of conditional effective service times (time interval between two consecutive instants at which a priority queue has an opportunity to transmit a message) of each priority queue. The condition is assigned on the basis of the contribution of message transmission time to the effective service time. The approximate mean waiting time for each priority queue is determined using the well-known results from Kuehn (1979), who first introduced the conditional cycle time. The approximate analytical model is validated by comparison with the simulation results     

基于优先级的相控阵测量雷达调度设计

介绍了一种基于优先级的相控阵测量雷达调度设计。根据雷达具体测量要求划分了多个任务调度优先级．分析了远程弹道导弹测量任务对相控阵测量雷达数据率的要求。讨论了能量调度的相关约束条件，给出了系统实现框图。通过综合时间间隔门限的选择调整，完成对多个目标的搜索、验证、跟踪和目标特性测量等任务。     

Queue‐based congestion detection and multistage rate control in event‐driven wireless sensor networks

Protocols for sensor networks have traditionally been designed using the best effort delivery model. However, there are many specific applications that need reliable transmissions. In event‐driven wireless sensor networks, the occurrence of an event may generate a large amount of data in a very short time. Among them, some critical urgent information needs to be transmitted reliably in a timely manner. In this scenario, congestion is inevitable because of the constraints in available resources. How to control the congestion is very important for the reliable transmission of urgent information. To address this problem, we propose a queue‐based congestion detection and a multistage rate control mechanism. In our proposed mechanism, not only the current queue length but also the queue fluctuation are adopted as indications of congestion. Each sensor node evaluates its congestion level locally and determines its congestion state with a state machine. We design a multistage rate adjustment mechanism for nodes to adjust their rates depending on their congestion states. We also distinguish high‐priority critical traffic from low‐priority non‐critical traffic. Extensive simulation results confirm the superior performance of our proposed protocol with respect to throughput, loss probability, and delay.Copyright © 2012 John Wiley & Sons, Ltd.     

一种带优先级队列的千兆以太网MAC设计

在以太网应用越来越广泛的背景下,针对某局域网具有传输数据量大和保持部分数据实时性的特点,采用了包含两种不同优先级帧的千兆以太网方案。基于Actel FPGA设计了一种带优先级队列的千兆全双工以太网MAC(Media access control),实现千兆以太网数据帧的收发,并对高优先级数据提供实时性支持。从分析含优先级字段的MAC帧结构着手,对MAC进行了模块划分,接着重点阐述了接收控制模块、发送控制模块和优先级队列模块。最后在ModelSim平台下对整个MAC进行了仿真验证;并使用Synplify进行了综合,结果表明GMII接口部分工作频率能达到141 MHz,内部模块工作频率能达到79 MHz,满足设计要求。     

Network queue scheduling algorithm based on self-similar traffic level grading prediction

Self-similarity characteristic of network traffic will lead to the continuous burstness of data in the network.In order to effectively reduce the queue delay and packet loss rate caused by network traffic burst,improve the transmission capacity of different priority services,and guarantee the service quality requirements,a queue scheduling algorithm P-DWRR based on the self-similarity of network traffic was proposed.A dynamic weight allocation method and a service quantum update method based on the self-similar traffic level grading prediction results were designed,and the service order of the queue according was determined to the service priority and queue waiting time,so as to reduce the queuing delay and packet loss rate.The simulation results show that the P-DWRR algorithm can reduce the queueing delay,delay jitter and packet loss rate on the basis of satisfying the different service priority requirements of the network,and its performance is better than that of DWRR and VDWRR.     

带优先权与不耐烦顾客排队模型的模拟仿真

考虑一个有两类顾客到达的单服务台的排队系统。两类顾客的到达过程均为泊松过程,第一类顾客较第二类顾客具有强占优先权,且第二类顾客由于第一类顾客的到达而变得不耐烦,其＂耐性时间＂服从负指数分布。两类顾客的服务时间服从相同参数的负指数分布,服务规则是强占优先服务,在高负荷条件下用Matlab编程对此排队系统进行模拟仿真,为处理此类排队问题提供了一个新方法。     

Delay Analysis of a Time Division Multiple Access (TDMA) Channel

The delay performance of a Time Division Multiple Access (TDMA) channel for transmitting data messages is considered. The channel is assumed to be fixed assigned to a station with unlimited buffer capacity and Poisson message arrivals. Each message gives rise to one or more packets for transmission into fixed-length time slots. The steady-state probability generating function of the queue size is derived. A formula for the expected message delay is given. The analysis is then generalized to a nonpreemptive priority queue discipline; expected message delay formulas are given for the priority classes.     

基于优先队列的最小生成树算法

本文提出一个获取连通网络是小生成树的算法。该算法采用一个优先队列组织各顶点集合，每次根据边的权值对队列头集合进行增长。由于对每个顶点的相关联边进行了按权值分级排序的预处理，算法获取具有。个预示e条边的无向连通网络的最小生成树的期望时间是O（e*loglogn）。     

A VLSI priority packet queue with inheritance and overwrite

Reliable priority-based flow-control is essential for real-time applications involving hard-deadlines. However, the use of first-in-first-out (FIFO) queues in such systems introduces priority inversion resulting in unbounded transmission delays. For this reason, a priority transmission queue is critical for multimedia and mission-critical systems. Yet very few priority queue implementations exist. This paper presents the design of a novel VLSI priority packet queue (PPQ), implemented in 1.2 μm CMOS technology. It achieves fast operation by manipulating its contents in terms of packet segments, rather than individual words. Similar to paged memory, this new segmented architecture greatly reduces implementation cost by reusing segments and avoiding storage area fragmentation. By distributing the computationally intensive priority comparison operation over the access time for an entire segment, the PPQ achieves 96% of the speed of a high-speed packet FIFO. The PPQ can either perform priority inheritance or overwrite lower priority packets to minimize the impact of queue overflow. In addition, it is suitable as a general computer network interface buffer, since it robustly handles asynchronous read and write clocks of greatly disparate frequencies. Our initial implementation achieves well over twice the speed of a nonpipelined approach with minimal additional overhead. Furthermore, scaling this design to larger capacities and more priority levels results in an even greater improvement in speed over conventional approaches