基于仿真器的源码级调试器设计与实现

根据嵌入式开发的特点,采用构件组装技术对基于仿真器的调试器进行设计,模块化各个部件,减少仿真器和调试器的耦合性,使基于仿真器的调试器能够适应多种仿真器,具有调试信息存储和解耦功能模块的能力,实现了调试功能的可扩展性.此外,结合当前主流调试技术,阐述了ELF文件格式,对源码级调试器的原理、使用方法和运行性能进行了重点分析.     

基于流分析的可执行程序结构化表示工具

直接面向可执行程序进行安全漏洞分析时,首先需要得到二进制代码的中间语言表示。探讨了流分析技术在汇编代码理解中的应用,并在Linux平台上实现了一个轻量级汇编代码结构化表示工具BESTAR。该系统利用控制流和数据流分析技术识别通用控制结构,分析程序执行流,重构表达式和函数,发现数据依赖关系,将汇编代码转换成一个结构化、易理解的中间语言程序,为进一步进行安全分析打下了基础。     

A program design language based software maintenance tool

Program design languages are an increasingly important method of expressing the detailed design of a software system. Such languages can be modelled using a data structure known as a semantic net. This paper describes a maintenance tool for program design languages based on such a data structure. The tool allows the user to interrogate a semantic net using an interactive procedural language in order to derive information necessary for software maintenance. The technique upon which this tool is based is applicable to the maintenance of activities throughout the software lifecycle.     

Designing a source-level debugger for cognitive agent programs

When an agent program exhibits unexpected behaviour, a developer needs to locate the fault by debugging the agent’s source code. The process of fault localisation requires an understanding of how code relates to the observed agent behaviour. The main aim of this paper is to design a source-level debugger that supports single-step execution of a cognitive agent program. Cognitive agents execute a decision cycle in which they process events and derive a choice of action from their beliefs and goals. Current state-of-the-art debuggers for agent programs provide insight in how agent behaviour originates from this cycle but less so in how it relates to the program code. As relating source code to generated behaviour is an important part of the debugging task, arguably, a developer also needs to be able to suspend an agent program on code locations. We propose a design approach for single-step execution of agent programs that supports both code-based as well as cycle-based suspension of an agent program. This approach results in a concrete stepping diagram ready for implementation and is illustrated by a diagram for both the Goal and Jason agent programming languages, and a corresponding full implementation of a source-level debugger for Goal in the Eclipse development environment. The evaluation that was performed based on this implementation shows that agent programmers prefer a source-level debugger over a purely cycle-based debugger.     

基于有用时序偏差的时序优化方法

提出了一种利用有用时序偏差来提高电路性能的方法,利用时钟偏差规划算法在时钟树综合之前对时序偏差重新调整规划,以提高电路的性能.使用ISCAS89作为实验对象来验证算法并进行了分析.     

Experiments on six commercial TCP implementations using a software fault injection tool

TCP, the de facto standard transport protocol in today's operating systems, is a very robust protocol that adapts to various network characteristics, packet loss, link congestion, and even significant differences in vendor implementations. This paper describes a set of experiments performed on six different vendor TCP implementations using ORCHESTRA, a tool for testing and fault injection of communication protocols. These experiments uncovered violations of the TCP protocol specification, and illustrated differences in the philosophies of various vendors in their implementations of TCP. The paper summarizes several lessons learned about the TCP implementations through these experiments. © 1997 John Wiley & Sons, Ltd.     

Specification and analysis of timing properties in a case tool CONRAD

The methods and environments for developing real-time systems have become an important factor encouraging the rapidly increasing role of real-time systems in everyday life. In spite of the remarkable success in applying software engineering tools to real-time systems, the analysis of timing properties and the consistency proofs of time-constraints is still in its infancy.This paper suggests a solution which improves the ability to study and prove time-correctness of real-time systems. CONRAD (CONtrol software Requirements, Analysis and Design) is a set of tools which allows formal specification and analysis of timing properties (the EDITOR), and informal analysis (animation) starting from the early stages of the requirements specification. This paper describes the possibilities provided by the EDITOR.     

Experiments in program verification using Event-B

The Event-B method can be used to model all sorts of discrete event systems, among them sequential programs. In this article we describe our experiences with using Event-B by way of two examples. We present a simple model of a factorial program, explaining the method, and a more intricate model of the Quicksort algorithm, providing some insights into strengths and weaknesses of Event-B. The two models are interspersed with our observations and some suggestions of how, we believe, Event-B could evolve. This evaluation of Event-B is intended to serve for determining directions for the evolution of Event-B and judging progress. It is our hope that the observations and suggestions can also be put to use for similar modelling formalisms, such as Z, ASM or VDM.     

利用GNU工具实现汇编程序覆盖测试

在研究了现有覆盖测试原理、Gcov的覆盖测试的机制后,结合汇编程序覆盖测试的特点,充分利用现有资源,提出了一个简单易行的对汇编程序进行覆盖测试的方案,并通过原型程序证明了可行性。     

Five-axis tool path generation for a flat-end tool based on iso-conic partitioning

Traditionally, for the flat-end tool, due to the intertwined dependence relationship between its axis and reference point, most 5-axis tool-path generation algorithms take a decoupled two-stage strategy: first, the so-called cutter contact (CC) curves are placed on the part surface; then, for each CC curve, tool orientations are decided that will accommodate local and/or global constraints such as minimum local gouging and global collision avoidance. For the former stage, usually simplistic “offset” methods are adopted to determine the cutter contact curves, such as the iso-parametric or iso-plane method; whereas for the latter, a common practice is to assign fixed tilt and yaw angle to the tool axis regardless the local curvature information and, in the case of considering global interference, the tool orientation is decided solely based on avoiding global collision but ignoring important local machining efficiency issues. This independence between the placement of CC curves and the determination of tool orientations, as well as the rigid way in which the tilt and yaw angle get assigned, incurs many undesired problems, such as the abrupt change of tool orientations, the reduced efficiency in machining, the reduced finishing surface quality, the unnecessary dynamic loading on the machine, etc. In this paper, we present a 5-axis tool-path generation algorithm that aims at alleviating these problems and thus improving the machining efficiency and accuracy. In our algorithm, the CC curves are contour lines on the part surface that satisfy the iso-conic property — the surface normal vectors on each CC curve fall on a right small circle on the Gaussian sphere, and the tool orientations associated to a CC curve are determined by the principle of minimum tilt (also sometimes called lead) angle that seeks fastest cutting rate without local gouging. Together with an elaborate scheme for determining the step-over distance between adjacent CC curves that seeks maximum material removal, the presented algorithm offers some plausible advantages over most existing 5-axis tool-path generation algorithms, particularly in terms of reducing the angular velocity and acceleration of the rotary axes of the machine. The simulation experiments of the proposed algorithm and their comparison with a leading commercial CAM software toolbox are also provided that demonstrate the claimed advantages.     

From Hilbert’s program to a logic tool box

In this paper I discuss what, according to my long experience, every computer scientists should know from logic. We concentrate on issues of modeling, interpretability and levels of abstraction. We discuss what the minimal toolbox of logic tools should look like for a computer scientist who is involved in designing and analyzing reliable systems. We shall conclude that many classical topics dear to logicians are less important than usually presented, and that less known ideas from logic may be more useful for the working computer scientist.     

Optimization of tool change timing in a nut forming process using genetic algorithms

In this study, we consider an optimization problem arising from tool change scheduling of a nut forming process. The process has nine punches with different life spans. The objective of the study is to optimize the tool change timing of the nine punches in order to maximize the production yield. The punch life spans can be extended by means of Ti coating, but coated punches are more expensive. We also evaluate whether it is worth using coated punches. A cost model is developed for the nut forming process. In the developed cost model, we consider the reliability of the nine punches, the periods taken for changing punches, scrap cost and production yield. The cost function for the process is complex, and is difficult to be solved using conventional optimization methods. Therefore, genetic algorithms are used to solve the problems. We have developed our own genetic algorithms using Java programs and applied the developed genetic algorithms to provide solutions to the optimization problem.     

SPARC平台模拟器源码级调试系统的研究与实现

软件模拟器采用软件思想模拟真实硬件工作情况,作为嵌入式系统研究的基础研发工具,被广泛应用于体系结构设计调优、软硬件协同设计领域。研究提出一种在SPARC指令集模拟器平台上实现源码级调试系统的方法,一方面该方法使用SPARC交叉调试器对运行于SPARC指令集模拟器上的应用程序进行源码级调试,有效避免了单独实现源码级调试器所带来的调试信息解析困难、可靠性难以验证的弊端;另一方面提出了在集成开发环境下源码级调试系统的高效集成机制,有效解决了进程间切换延时开销大、界面僵死等问题,为SPARC平台嵌入式系统开发人员提供了一种支持图形化界面的高可靠性源码级调试系统。通过具体实现分析,对整个调试系统进行了性能评估。     

Cobra: a light-weight tool for static and dynamic program analysis

Static source code analysis tools have become indispensable for the development of reliable software applications. The best analyzers can reveal subtle flaws in a code base, but they can also be slow. In part this is due to the collection of detailed information about the possible data and control flow of an application to support the broadest possible range of analyses. For larger code bases it is not unusual that even the best of breed static analyzers can take an hour or more to complete an analysis. In this paper we describe a framework for a much faster, but more light-weight type of static analysis that can support interactive use for standard types of queries. The Cobra tool we designed for this purpose can scale to explore millions of lines of code interactively. The tool is mostly language agnostic, and can therefore easily be configured to resolve even dynamic program analysis queries.     

Estimation of productivity increase for timing analysis tool chains

Within the scope of the ALL-TIMES project, not only were tool interfaces designed and implemented but also new, powerful timing analysis methodologies constructed. To gauge the effectiveness of these results we used a number of methods to assess the productivity increase that would be achieved by introducing the new techniques. We collect and report on the conclusions of these assessments.     

基于单片机的定时插座设计

日常生活中,电动玩具、电动车、手机电池等电子产品的充电电池寿命都是有限的,充电时间过长容易损坏电池,而且长时间充电浪费电力。而有些功能单一的电器又没有定时开关功能。利用定时插座充电可以节约电力,也可以防止由于充电过久而影响电池寿命;使用定时插座控制功能单一的电器,可以为其提供定时功能,更大程度地满足人们生活需要。设计了一个以STC89C52单片机为控制核心的定时开关插座,可以控制220 V/10 A的插座,在24 h内可预先设定定时范围,同时还能通过红外遥控远距离控制插座的开关。     

一种基于FPGA的在线程序升级方案

介绍了一种基于XILINX FPGA的在线程序升级方案,该方案不需要额外增加器件,在不改变硬件状态的前提下,实现产品的软件功能升级。由于对配置芯片(PROM)的所有操作均由FPGA的内部逻辑实现,故此方案具有良好的移植性和扩展性。