用Real-time CORBA开发嵌入式实时系统

阐述了实时CORBA标准的内容，并给出了用它构建一个嵌入式系统的应用举例。     

嵌入式实时系统中断管理技术研究

嵌入式实时系统中断管理技术直接影响到系统的实时响应性能。本文通过对嵌入式内核中断管理技术的研究,归结出“中断前-后段处理”模型;同时,针对一些处理器中多个外部中断共用一个向量的问题,提出一种单向量多中断处理映射技术,并在PowerPCMPC860处理器上实现DeltaOS内核时,验证此技术的有效性。     

嵌入式实时系统的检验技术

检验是产品周期的最后一个阶段,特别在要求高可靠性时要给予特别的关注.本文提出一种新的检验方法来避免嵌入式系统的实时要求带来的复杂性.     

嵌入式分布实时系统自适应资源管理架构

分析了开放嵌入式分布实时(Distributed Real-time and Embedded,DRE)系统的自适应资源管理需求,针对传统静态资源管理方法的不足,提出了一种面向开放DRE系统的自适应资源管理架构;该架构采用动态任务管理、实时资源分配和自适应控制三种关键技术,能够更加适用于开放、动态的环境,有效应对资源约束和资源状态、应用程序QoS的变化;提高系统性能和稳定性;屏蔽底层硬件资源的异构性,为上层应用提供统一的服务接口。     

基于消息服务器的嵌入式实时系统进程管理研究

本文针对嵌入式实时系统提出基于消息服务器的进程管理机制。该机制基于端口对象理论,采用真正的消息驱动,实现了调度算法的动态可重构,减小了系统开销,提高了系统的可调度性,并通过PV通令机制实现了实时分布式进程管理。文章最后给出了系统可调度的充要条件。     

Windows NT—新的嵌入式与实时系统的开发平台

扼要地说明了ＷｉｎｄｏｗｓＮＴ作为嵌入式与实时系统的开发平台的可行性及其特点，以作为开发人员在平台选择时的参考。     

基于反馈控制的嵌入式实时系统调度算法设计

针对嵌入式实时系统在系统负载模型不确定的情况下系统的实时任务错过率过高以及调度稳定性差的问题,提出了一个基于反馈控制的调度模型.该模型主要由改进的多级队列调度器和3个控制器(准入控制器、执行等级控制器、比例积分微分(PID)控制器)组成.任务的错过率偏差反馈到PID控制器,产生相应的调整量并作用于其他两个控制器,对实时任务的执行等级进行调整, 经过调整的任务被调度器调度执行.在对模型中每个部件进行了一些结构调整和改进设计之后,将该调度模型应用于嵌入式可配置操作系统(eCos)中.实验结果表明,该模型降低了任务的时限错过率,同时解决了系统频频超载的问题.     

嵌入式实时系统及其在烟机中的应用

近年来,嵌入式实时系统已经在工业等各个领域得到广泛关注与应用.本文介绍嵌入式实时系统的特点、关键技术、优势,以及嵌入式实时系统在高档卷接设备和包装设备中的应用情况;展望嵌入式实时系统的发展趋势及在烟机上的应用前景.     

嵌入式实时系统RTLINUX的实现和测试

RTLINUX是LINUX的嵌入式实时核心,该文首先深入地分析RTLINUX的实现原理和机制,给出了在RTLIN UX下编写实时应用程序的方法。并在此基础上,设计和实现了测试RTLINUX实时性能的系统,并对测试结果进行了分析。     

一种实时异构嵌入式系统的任务调度算法

异构分布式系统已被广泛应用在实时嵌入式系统中,而调度算法是在进行嵌入式系统综合时,确保系统实现性能目标的一个关键问题,这是一个NP-完全问题.现有的算法主要是启发式算法,性能还有待提高.提出了一个异构分布式系统的动态BLevel优先(dynamic BLevel first,简称DBLF)算法,算法选择就绪任务中动态BLevel值最大的任务进行调度,用插入法为任务分配处理器,遵循以下3个插入原则:满足任务先后顺序关系;任务的最早完成时间(earliest-finish-time,简称EFT)最小;在EFT相等时,优先分配到利用率较低的处理器上.与现有算法比较可以看出,DBLF算法可以有效降低调度长度.     

Methods for the Development of Distributed Real-Time Embedded Systems Using VDM

The development of distributed real-time embedded systems presents a signi-ffcant practical challenge both because of the complexity of distributed computation and because of the need to rapidly assess a wide variety of design alternatives in early stages when requirements are often volatile. Formal methods can address some of these challenges but are often thought to require greater initial investment and longer development cycles than is desirable for the development of noncritical systems in highly competitive markets.In this paper we propose an approach that takes advantage of formal modelling and analysis technology in a lightweight way, making signi cant use of readily available tools. We describe an incremental approach in which detail is progressively added to abstract system-level speci cations of functional and timing properties via intermediate models that express system architecture, concurrency and distribution. The approach is illustrated using a modelof a home automation system. The models are expressed using the Vienna Development Method (VDM) and are validated primarily by scenario-based tests.     

A Framework for Software Fault Tolerance in Real-Time Systems

Real-time systems often have very high reliability requirements and are therefore prime candidates for the inclusion of fault tolerance techniques. In order to provide tolerance to software faults, some form of state restoration is usually advocated as a means of recovery. State restoration can be expensive and the cost is exacerbated for systems which utilize concurrent processes. The concurrency present in most real-time systems and the further difficulties introduced by timing constraints suggest that providing tolerance for software faults may be inordinately expensive or complex. We believe that this need not be the case, and propose a straightforward pragmatic approach to software fault tolerance'which is believed to be applicable to many real-time systems. The approach takes advantage of the structure of real-time systems to simplify error recovery, and a classification scheme for errors is introduced. Responses to each type of error are proposed which allow service to be maintained.     

一种嵌入式系统实时性能分析的融合机制

许多嵌入式系统要求硬实时或者软实时地执行,为了确保这些要求得到满足,不仅要对单个任务或代码段的执行时间进行测量,同时还必须确定整个系统的实时性能。为此,针对导致传统的纯软件方法测量精确度低的两个主要原因,借助于多源数据的信息融合思想,依据改进后的纯软件的实时代码执行时间的测量方法,提出了一种用于嵌入式系统实时性能分析的融合机制,基于这种机制,设计和开发人员能够查明时限错误,找出需要优化的代码以解决期限错过问题,并确定特定环境下实时任务集的可调度性。     

A Real-Time Framework for Model-Predictive Control of Continuous-Time Nonlinear Systems

A new formulation of model-predictive control (MPC) for continuous-time nonlinear systems is developed, which allows for the use of ldquoreal-timerdquo (RT) optimization techniques in which the solution to the finite-horizon optimal control problem (OPC) evolves within the same timescale as the process dynamics. The computational savings of the RT solver are enhanced by the unique framework within which the OPC is posed, enabling significant reduction in the dimensionality of the search for situations where computational speed takes priority over optimality of the solutions. This framework, and its associated proof of stability, encompasses results on sampled-data (SD) nonlinear model-predictive control (NMPC) implementation as a special case.     

基于模型的嵌入式系统性能分析框架

在现代嵌入式系统中,性能的重要性日益凸显.传统的基于测量的性能分析方法在运行时对性能进行测试,往往在代码实现后才考虑实施.若此时发现的问题是体系结构或设计因素造成的,修复的代价将非常昂贵.提出了一种基于形式化模型的性能分析（formal method-based performance analysis,简称FMPA)方法框架,希望在系统开发的早期,对系统设计模型进行性能分析,以便尽早发现并解决潜在的性能问题.FMPA具有统一的对外接口（UML-MARTE),基于多种形式化模型,并可对多种系统性能指标进行分析.该方法适用于基于模型的开发过程,可为实时嵌入式系统的设计开发提供多项性能指标的参考.通过介绍利用实时模型检测技术分析响应时间与吞吐量,利用概率模型检测技术分析系统可靠性,以及FMPA方法的支撑工具FMPAer的总体设计方案,说明了FMPA方法框架的可行性.     

嵌入式实时系统的软件需求检测

以需求描述模型HRFSM(hierarchical finite state machines based on rules)为基础,提出了一个嵌入式实时系统软件的动态执行模型(dynamic execution model,简称DEM)和基于该模型的检测方法.由于DEM能将控制流、数据流和时间有效地集成为一体,故提出的检测方法能检测嵌入式实时系统的软件需求的一致性和完全性.该检测方法由3种侧重点不同的检测形式组成,并能在检测过程中提供一些重要的检测信息.分析员可以利用基于该检测方法的工具灵活地对嵌入式实时系统的软件需求进行检测,以提高分析和检测软件需求的效率.     

Implementation of Hard Real-Time Embedded Control Systems

Although the domain of hard real-time systems has been thoroughly elaborated in the academic sphere, embedded computer control systems –- being an important component in mechatronic designs –- are seldom dealt with consistently. Often, off-the-shelf computer systems are used, with no guarantee that they will be able to meet the requirements specified. In this paper, a design for embedded control systems is presented. Particularly, the paper deals with the hardware architecture and design details, the operating system, and high-level real-time language support. It is shown how estimates of process run-times necessary for schedulability analysis can be acquired on the basis of deterministic behavior of the hardware platform.     

复杂实时嵌入式系统建模与设计方法研究

提出了一种面向角色(Actor-Oriented)的复杂实时嵌入式系统建模与设计方法．该方法首先根据不同的计算模型(Computation Model)和不同的抽象层次(Abstract Hierarchy)将嵌入式系统划分为多个具有单一计算模型的子系统，然后按某一领域的专业知识构造这些子系统．再将这些子系统综合成一个整体模型，加以仿真．最后从调试好的模型自动生成软件代码和硬件描述语言，从而完成设计工作．还介绍了面向角色集成开发环境，并根据实例分析了该方法的有效性和优点。