分布式航电系统通用开放式软件架构设计研究

随着我国科技的发展,分布式航电系统是目前我国航空电子系统(DIMA)中研究领域以及应用领域最广的架构.在DIMA中,计算能力、传感器、内存以及执行器接口都是系统任务共享系统中的资源.航电系统里面包含的通用设备提供的资源,可以在飞机上的所有位置进行任意安装.随着飞机设备和任务配置变得越来越大,同时也越来越复杂,人工在进行...     

用于开放式系统的二维优先级实时调度

提出了一种新的用于开放式系统的调度机制,即二维优先级实时调度,它不仅划分任务优先级,还划分调度策略优先级.任务的执行顺序由其调度策略优先级和任务优先级共同决定.它不仅可以解决传统优先级调度机制中机制与调度策略不能相分离的问题,还提高了效率.这种机制中引入的CPU带宽控制策略,可以根据需要实现硬实时、软实时、混合实时不同目标的实时系统,并简化了任务可调度性分析,且可以为不同权限或级别的用户提供不同QoS服务.这种调度架构不仅效率高,而且具有很强的开放性,适用广、易扩展.     

某型号航电系统CNI分系统飞行任务可靠性评估

本文使用飞行任务可靠性分析图,对通讯、导航、敌我识别分系统等４种工作模式下的飞行任务可靠性作了建模、估算,并求出了成功概率,从而定量地评估了该分系统的飞行任务可靠性。     

无线双向中继网络编码系统用户调度方法性能分析

提出了一种用于无线双向中继网络编码系统的用户调度方法,基站或中继在调度用户时,综合考虑基站与中继和用户与中继之间信道的影响,使得基站采用原有预编码算法时,具有了波束赋形增益。仿真表明,系统吞吐量和首次传输的正确率明显提升,且算法复杂度低、用户公平性好,便于在实际系统使用。     

中继增强型蜂窝网络资源调度算法研究

引入中继到蜂窝网络增加了资源调度的复杂度,单跳网络的帧结构以及现有的资源调度算法不再适用。文章基于一个可行的帧结构,推广了Round-Robin算法,提出了“贪婪轮询”和“部分比例公平”算法。仿真结果表明,提出的算法较大地提高了系统性能,同时验证了中继增强型蜂窝网络对于单跳网络的优越性。     

实时网络的分布式调度

针对主—从结构实时网络的性能特点,提出了一种基于EDF的主节点分布式实时任务调度算法,给出了该调度算法下实时任务组的可调度的充分条件。仿真测试表明,该调度算法满足实时约束,适合于主—从结构的实时网络调度。     

HSUPA系统中的快速分组调度技术

HSUPA是WCDMA上行链路的演进标;住,在此标准中采用了基于Node B控制的快速上行调度和快速数据重传的技术本文对HSUPA系统中的快速分组调度进行了介绍和综述,并对分组调度所使用的关键技术进行了详细分析。     

嵌入式实时多任务操作系统中的程序设计

本文主要介绍了嵌入式实时多任务操作系统中的任务，任务的调度、任务间的通信，并给出了基于实时多任务系统的设计原则。     

通用航空综合化航电系统技术研究与设计

本文主要围绕通用航空综合化航电设备的实际工程开发,研究了综合化航电系统总体技术,阐述了综合化航电系统架构的总体方案设计,给出了综合化航电机架的和主要通信、导航、监视 LRM 航电组件的设计方法。     

Energy Efficient Real-Time Task Scheduling for Embedded Systems with Hybrid Main Memory

Available energy becomes a critical design issue for the increasingly complex real-time embedded systems. Phase Change Memory (PCM), with high density and low idle power, has recently been extensively studied as a promising alternative of DRAM. Hybrid PCM-DRAM main memory architecture has been proposed to leverage the low power of PCM and high speed of DRAM. In this paper, we propose energy-aware real-time task scheduling strategies for hybrid PCM-DRAM based embedded systems. Given the execution time variation when a task is loaded into PCM or DRAM, we re-design the static table-driven scheduling for a set of fixed tasks, as well as the Rate-Monotonic (RM) and Earliest Deadline First (EDF) scheduling policies for periodic task sets. Furthermore, since the actual execution time can be much shorter than the worst-case execution time in the actual execution, we propose online schedulers which migrates the tasks between PCM and DRAM to optimize the energy consumption by utilizing the slack time resulted from the completed tasks. All the proposed algorithms minimize the number of task migrations from PCM to DRAM by ensuring that aperiodic tasks are not migrated while each periodic task instance can be migrated at most once. Experimental results show our proposed scheduling algorithms satisfy the real-time constraints and significantly reduce the energy consumption.     

A Design Perspective for Real-Time Task Control in Distributed Systems

Industrial control systems have unique system requirements which often require diverse systems of cooperating components to achieve system goals. System requirements may be specified in the form of tasks which must be executed in sequential order. This paper presents a design perspective in which such problems can be decomposed and implemented by a distributed system in a modular-fashion. A System Scheduler is responsible for all flow control functions. Loosely coupled Task Processors respond to instructions from the scheduler to perform the control algorithm Parallelism, redundancy, and distributed control are presented as methods of improving system performance and reliability.     

航空电子蓝图系统实时性设计

在新一代先进综合航空电子系统体系结构中,采用蓝图系统来完成航电系统结构的描述;针对蓝图系统进行实时性保障研究,是对蓝图系统展开研究的一个重要方面。首先探讨了蓝图系统的结构,在此基础上分析了任务在航空电子系统中的加载和运行模式,并针对6种典型运行模型,给出了蓝图系统实时性保障的判定定理,最后通过计算机仿真验证的方式对这6种典型运行模型的可调度性进行了分析和对比。     

无线移动网络环境中混合式任务调度策略的研究与实现

无线移动网络具有性能不稳、易受外界干扰等特点,要求实时调度必须考虑网络变化影响.因为网络性能变化可直接导致网络延时变化,即任务耗费在网络传输上的时间发生变化,从而对任务集可调度性产生影响.传统调度算法大多未考虑网络因素.由此提出适应于网络性能不稳定环境下的混合式任务调度策略,测试结果表明该策略有利于提高混合实时任务在网络性能动态变化环境下的可调度性.     

Real-Time Dynamic Voltage Loop Scheduling for Multi-Core Embedded Systems

In this brief, we propose a novel real-time loop-scheduling technique to minimize energy consumption via dynamic voltage scaling (DVS) for applications with loops considering transition overhead. One algorithm, dynamic voltage loop scheduling (DVLS), is designed integrating with DVS. In DVLS, we repeatedly regroup a loop based on rotation scheduling and decrease the energy by DVS as much as possible within a timing constraint. We conduct the experiments on a set of digital signal processing benchmarks. The experimental results show that DVLS achieves big energy saving compared with the traditional time-performance-oriented scheduling algorithm     

A Novel Battery-Aware Task Scheduling Algorithm for Multiprocessor Systems

In battery-powered portable devices, the most important design goal is maximizing the battery lifetime. This paper addresses the problem of battery- aware task scheduling on multiprocessor systems to extend the battery lifetime, and proposed a Critical-path based battery-aware task scheduling （CPbBATS） algorithm with a novel efficient flow. Experiments on hundreds of task graphs each having 10 to 100 tasks show that, compared with algorithm that simply sequences tasks with their highest voltages and utilizes the slack by the latest possible task, the CPbBATS achieved 3.3%-6.1% reduction on apparent charge lost which means longer battery lifetime, 3.6%-8.3% reduction on actual charge lost which means lower energy consumption, and average 31.99% reduction on the CPU runtime which means much lower computa- tional complexity.     

分布式卫星系统数传调度研究

近年来随着我国在轨遥感卫星数量的不断增加,对当前中继星系统的数传能力提出了更高的要求。在卫星平台载荷能力受限的情况下,分布式卫星系统成为大幅提升中继星系统性能的可行方案。针对分布式卫星系统的数传任务调度问题,综合考虑系统与中低轨航天器用户之间的可见时间窗口、卫星剩余资源及数传任务属性等约束条件,提出了基于粒子群优化(PSO)的多星多任务数传调度方法。根据实际中继系统任务量级对经典PSO算法进行了改进,并通过计算机仿真验证了改进算法的有效性。     

Optimal Semi-Partitioned Scheduling in Soft Real-Time Systems

Semi-partitioned real-time scheduling algorithms extend partitioned ones by allowing a (usually small) subset of tasks to migrate. The first such algorithm to be proposed was directed at soft real-time (SRT) sporadic task systems where bounded deadline tardiness is acceptable. That algorithm, called EDF-fm, has the desirable property that migrations are boundary-limited, i.e., they can only occur at job boundaries. However, it is not optimal because per-task utilization restrictions are required. In this paper, a new optimal semi-partitioned scheduling algorithm for SRT sporadic task systems is proposed that eliminates such restrictions. This algorithm, called EDF-os, preserves the boundary-limited property. In overhead-aware schedulability experiments presented herein, EDF-os proved to be better than all other tested alternatives in terms of schedulability in almost all considered scenarios. It also proved capable of ensuring very low tardiness bounds, which were near zero in most considered scenarios.