基于ARM9-Linux的注塑机伺服控制系统

全电动注塑机的控制系统任务繁多且要求实时性强。结合全电动注塑机的工艺特点,提出了以ARM9处理器为核心的全电动注塑机硬件系统,并利用嵌入式操作系统Linux提供的多进程多线程通信机制进行软件设计,从而满足全电动注塑机的各种伺服控制要求。     

面向可重构系统的eCos拓展

针对可重构系统中任务模型灵活性差、硬件任务重构延时长、FPGA资源利用率低等问题,提出了将应用程序划分为软件任务和混合任务的划分模式,并在eCos的基础上,通过重构控制机制、混合任务管理机制、通信机制三方面的拓展,设计了支持可重构系统的嵌入式操作系统框架eCos4RC。仿真结果表明,eCos4RC实现了对混合任务的有效管理,在兼容eCos多线程机制的同时提高了应用程序执行速度和可重构资源利用率,为可重构计算平台提供了良好的运行环境支持。     

基于嵌入式操作系统的健康监控机制设计与实现

针对嵌入式操作系统故障报告等问题，介绍了一种基于嵌入式操作系统的分级健康监控处理机制。该机制将嵌入式操作系统的故障等级主要分为进程级、模块级和直接处理级，将故障或系统警告以健康监控事件的形式通过消息队列传递到相应等级的处理进程中，并根据健康监控配置表选择相应的故障处理程序以实现故障处理。该机制在某嵌入式操作系统中验证了该健康监控机制的有效性和可靠性。     

基于安全域隔离的嵌入式系统的访问控制机制研究

针对嵌入式领域安全关键系统的信息安全问题,提出了基于安全域隔离的访问控制模型,采用分区间信息流隔离控制机制,结合分区间消息路由和消息权限鉴别机制,实现了分区操作系统中安全关键类应用任务的多级安全访问控制,并依据该模型设计了多级安全操作系统的访问控制机制。通过安全性分析证明,该机制使基于微内核的嵌入式操作系统能够防止非法的资源访问、身份伪装、信息泄露和隐秘通道等安全威胁;经过系统的性能测试表明,安全访问控制机制的引入使嵌入式操作系统的综合性能消耗约为10%左右。     

实时操作系统μC/OS-Ⅱ在TMS320VC5509上的移植

μC/OS-Ⅱ是一种基于优先级占先式的嵌入式操作系统,提供了任务管理、时间管理、内存管理以及任务之间的通信和同步等功能.由于其可移植性和可裁剪性,以及成功地应用到了商业系统中,本文介绍了该系统在TMS320VC5509 DSP上面的移植,并且通过仿真证明了其正确性.     

通信处理器的Boot Loader及I/O接口驱动程序

针对Ethernet/IP通信处理器的开发,采用S3C2410 ARM9微处理器和Windows CE.NET嵌入式操作系统,建立了通信处理器的Boot Loader和I/O接口驱动程序。Boot Loader与硬件高度相关,担负着初始化系统硬件和引导操作系统的双重任务。而I/O接口驱动程序使操作系统自动识别外围数据采集设备,为应用程序对底层设备的操控提供服务。实验测试表明该Ethernet/IP通信处理器运行稳定、可靠。     

基于嵌入式操作系统设计Agent的主控模块

在嵌入式操作系统VxWorks上实现一个Agent主控模块,通过模块内部的高内聚度和模块间的低耦合性,提高了软件系统的可靠性;通信协议采用流命令方式,便于扩充和增加功能;进程间通信传递消息指针而非消息体,减少拷贝时间从而减少协议处理时间,提高了通信通路性能;通过保证模块间共享接口函数的可重入性和对数据的互斥操作提高了系统安全性;提供了方便的测试机制以便实时掌握通信通路的性能及状态。     

开放系统桌面进程通信机制研究*

桌面系统由一系列应用程序组成,它们之间需要协作一致来完成特定的任务,这就要求应用程序能够高效、快速地进行通信。由于传统IPC机制和远程互操作体系并不适应桌面进程通信的要求,因此在开放系统领域中处于主流地位的桌面系统GNOME和KDE分别采用CORBA和DCOP作为桌面进程通信机制。一种新的用于统一各个不同桌面的进程通信机制DBUS也被制定出来。通过对各种通信机制进行分析和比较,抽象桌面进程通信的基本架构和特点,总结出设计和选择桌面进程通信机制的基本原则。     

数控系统网络通信平台的设计与实现

针对CMS/NML通信系统无法应用于内核空间的问题,提出了一种SM_ NML通信机制,为本地内核与用户进程提供了统一的通信接口,还可以方便地与CMS/NML结合实现内核进程与远程进程通信.该通信机制以字符设备为存储介质,利用缓冲池管理和读写管理为通信提供了底层支持,并在此基础上进行了封装,为用户提供了顶层通信接口.分析了SM_ NML通信机制的通信延迟,给出了一个具体的应用实例,验证了其可用性.     

μC/OS-Ⅱ嵌入式操作系统中抢占式调度策略分析

本文描述了嵌入式操作系统μC／OS-Ⅱ的调度机制,通过任务级调度和中断级调度不同的比较,看出该系统的抢占式调度策略的高效性。     

Rate-monotonic analysis for real-time industrial computing

Issues of real-time resource management are pervasive throughout industrial computing. The underlying physical processes of many industrial computing applications impose explicit timing requirements on the tasks processed by the computer system. These timing requirements are an integral part of the correctness and safety of a real-time system. It is tempting to think that speed (for example, processor speeds or higher communication bandwidths) is the sole ingredient in meeting system timing requirements, but speed alone is not enough. Proper resource-management techniques also must be used to prevent, for example, situations in which long, low priority tasks block higher priority tasks with short deadlines. One guiding principle in real-time system resource management is predictability, the ability to determine for a given set of tasks whether the system will be able to meet all of the timing requirements of those tasks. Predictability calls for the development of scheduling models and analytic techniques to determine whether or not a real-time system can meet its timing requirements. The author illustrates an analysis methodology, rate monotonic analysis, for managing real-time requirements in a distributed industrial computing situation. The illustration is based on a comprehensive robotics example drawn from a typical industrial application     

项重写系统的并行实现方案

项重写系统的并行归约可以提高归约的效率，在无共享内存的Ｔｒａｎｓｐｕｔｅｒ网络上实现时要考虑任务的分配，项的拼装，归约任务的控制等问题，其中怎么样减少机间的机内进程的通信慢提高系统效果的关键。本文从控制方式角度讨论在不同拓扑结构的Ｔｒａｎｓｐｕｔｅｒ网络上实现项重写系统的方案，重点介绍基于树形结构下的控制方法，进程安排和通讯形式。     

Understanding the materiality of writing from multiple sources

Writing research has typically focussed on the text production elements of writing. Many everyday writing tasks, however, cannot be characterized simply in terms of text production since they often involve the use of source materials to support the composition process. As such, these tasks are better thought of as hybrid tasks. Such hybrid tasks have been given relatively little attention in the literature and what little work has been done has taken a purely cognitive approach that downplays the material context within which the task takes place. Following Haas' critique of mainstream writing research which advocated the need to consider the material tools and artefacts in theories of writing, this paper takes a similar approach in relation to the hybrid tasks of writing while reading from multiple sources. A study is presented that explores a range of everyday writing from multiple sources in their real-world contexts. The study highlights a number of important characteristics of the interaction with the material artefacts used during these tasks and the impact that these have on the underlying cognitive processes. The hope is that these will begin to offer some grounding on which future theoretical understanding of these hybrid tasks can build, as well as providing useful insights into the design of technologies to support these tasks.     

基于模糊和证据理论的行为建模

针对人类行为模型系统中存在大量的复杂任务关系和过程,系统输出的概率不确定性等问题,提出了基于Mamdani-Zadeh推理范式和D-S证据理论的建模方法.这种方法把输入空间分割成人们比较容易理解和表达问题的小区域,使用Mamdani-Zadeh和模糊D-S规则控制信度函数的输出值,从而得到了用户预期焦化元的清晰值,实现了模型系统关系、过程简单化;并通过具体例子证实了此方法的精确性和有效性。     

Energy-aware mixed partitioning scheduling in standby-sparing systems

Previous standby-sparing techniques assume that all tasks don't access to shared resources. In addition, primary tasks and backup tasks are allocated to the primary processor and spare processor respectively. Spare processor schedules tasks with maximum processor speed. Unlike previous techniques, we have studied the problem of minimizing energy consumption and preserving the original reliability for dynamic-priority real-time task set with shared resources in a standby-sparing system. We propose a novel energy-aware mixed partitioning scheduling algorithm (EAMPSA). Earliest deadline first/dynamic deadline modification (EDF/DDM) scheduling scheme is used to ensure that the shared resources can be accessed in a mutual exclusive manner. Uniformly speed is used to the primary processor and the spare processor. In addition, we use the mixed mapping partitioning of primary and backup tasks method to map tasks. A novel method of mapping task is proposed i.e. the tasks which need to access to shared resources are mapped into the primary processor and the tasks which have no resource requirements are mapped into the spare processor. Furthermore, DVS and DPM techniques are used for both primary and backup tasks to save energy. The experimental results show that the EAMPSA algorithm consumes average 55.43% less energy than that of the SSPT algorithm.     

Performance estimation for real-time distributed embedded systems

Many embedded computing systems are distributed systems: communicating processes executing on several CPUs/ASICs. This paper describes a performance analysis algorithm for a set of tasks executing on a heterogeneous distributed system. Tight bounds are essential to the synthesis and verification of application-specific distributed systems, such as embedded computing systems. Our bounding algorithms are valid for a general problem model: The system can contain several tasks with hard real-time deadlines and different periods; each task is partitioned into a set of processes related by data dependencies. The periods of tasks and the computation times of processes are not necessarily constant and can be specified by a lower bound and an upper bound. Such a model requires a more sophisticated algorithm, but leads to more accurate results than previous work. Our algorithm both provides tighter bounds and is faster than previous methods     

基于进程投机并行的运行时系统设计与优化

投机并行化是解决遗留串行代码并行化的重要技术,但以往投机并行化运行时系统面临着诸多的性能问题,如任务分配不均衡、通信频繁、冲突代价高,以及进程启动,结柬频繁而导致开销过高等。为此,提出一种基于进程实现的投机并行化运行时系统。采用隐式单程序多数据的并行任务划分和执行模式。通过实现重甩进程的投机任务调度策略和委托正确性检查技术,降低投机进程启动/结束和通信的开销,提高投机进程的利用率,同时利用守护进程与投机进程协同执行的方式,确保在投机进程出现异常情况时程序也能正确执行。实验结果表明,该基于进程实现的投机运行时系统比同类型系统的性能提高231%。     

Using situation calculus for e-business agents

As the Internet grows, it is becoming less feasible for customers and merchants to manually visit each web site, analyze the information there, and make sound business decisions regarding the trading of goods or services. To cope with this evolution, software agents can be designed that are capable of automating the more routine, tedious, and time-consuming tasks involved in current trading processes. At a higher level agents may also be able to negotiate and make autonomous decisions and commitments on behalf of their owners.

This paper describes an agent implementation using the situation calculus, which offers a possibly unifying paradigm for dynamic agents. Interesting applications are currently being developed. Our contribution is a situation calculus agent system developed for e-business. Ongoing work is focused on implementing this system in an open marketplace environment.     

The effect of task order on the maintainability of object-oriented software

This paper presents results from a quasi-experiment that investigates how the sequence in which maintenance tasks are performed affects the time required to perform them and the functional correctness of the changes made. Specifically, the study compares how time required and correctness are affected by (1) starting with the easiest change task and progressively performing the more difficult tasks (Easy-First), versus (2) starting with the most difficult change task and progressively performing the easier tasks (Hard-First). In both cases, the experimental tasks were performed on two alternative types of design of a Java system to assess whether the choice of the design strategy moderates the effects of task order on effort and correctness.The results show that the time spent on making the changes is not affected significantly by the task order of the maintenance tasks, regardless of the type of design. However, the correctness of the maintainability tasks is significantly higher when the task order of the change tasks is Easy-First compared to Hard-First, again regardless of design. A possible explanation for the results is that a steeper learning curve (Hard-First) causes the programmer to create software that is less maintainable overall.     

面向人件服务的决策支持系统接口研究

针对决策任务结构化程度越来越低,以及所需缄默知识不可编码化的难题,在基于服务的决策支持系统架构基础上,提出将人件服务应用到决策支持系统中的理念。依次介绍了面向服务架构,人件服务概念及背景;分析了其应用特征和适用范围;重点提出了三种人件服务接口交互实现方式,以及决策支持系统的服务接口架构;以目标打击为例阐述了决策流程的服务调用和服务接口。