一种基于分层切片模型思想的源程序信息分析方案

作为软件理解的手段之一,程序切片技术通过寻找程序内部的相关性来分解程序,再通过对分解所得程序切片的分析达到对整个程序的分析和理解。程序切片算法必须建立在对源程序信息正确、完整分析的基础上。详细地描述了一种基于分层切片模型思想的程序信息提取方案。该方案已成功运用到一种Java程序切片工具模型JSTM（Java Slicing Tools Model)中。     

基于LLWin模块化语言与嵌入式设计的机器人控制系统设计

在工业机器人现代设计过程中,可以采用基于模型的嵌入式设计方法,进行机器人系统设计;在完成机器人总体方案设计后,用“慧鱼创意组合模型”拼装成机器人模型,采用LLWin模块化编程语言编制控制程序,对机器人进行控制,可以使机器人系统控制设计得到一个真实的验证,缩短设计周期,从而使控制系统设计优化。     

用VB开发函数作图软件

讨论了用ＶＢ对数据文件作标准函数曲线图的方法,实现了在图形任意２位置精确添加文字,并提供了示例程序。     

C语言与有限元程序设计

本文通过与FORTRAN77语言的比较,说明利用C语言开发有限元程序的可行性.结果表明,C语言不但完全可以实现FORIRAN77的语法功能,拥有更强大的实用编程环境,同时由于提供指针变量、动态内存分配函数和结构变量,使其编写的软件在维护性、可读性和内存利用效率方面具有明显的优势.文章最后还将C语言与最近出现的FORTRAN90作了简单比较.     

Video placement and configuration of distributed video servers on cable TV networks

A large-scale, distributed video-on-demand (VOD) system allows geographically dispersed residential and business users to access video services, such as movies and other multimedia programs or documents on demand from video servers on a high-speed network. In this paper, we first demonstrate through analysis and simulation the need for a hierarchical architecture for the VOD distribution network.We then assume a hierarchical architecture, which fits the existing tree topology used in today's cable TV (CATV) hybrid fiber/coaxial (HFC) distribution networks. We develop a model for the video program placement, configuration, and performance evaluation of such systems. Our approach takes into account the user behavior, the fact that the user requests are transmitted over a shared channel before reaching the video server containing the requested program, the fact that the input/output (I/O) capacity of the video servers is the costlier resource, and finally the communication cost. In addition, our model employs batching of user requests at the video servers. We study the effect of batching on the performance of the video servers and on the quality of service (QoS) delivered to the user, and we contribute dynamic batching policies which improve server utilization, user QoS, and lower the servers' cost. The evaluation is based on an extensive analytical and simulation study.     

计算思维理论指导下的程序设计教学改革实践

计算机思维是目前教育工作者重点研究的课题。从计算思维的内涵出发,依据思维教学理念,提出在程序设计课程中通过整合课程内容。构建基于课堂教学与实验教学相结合、课程作业与项目训练相结合及常规教学与网络教学平台相结合的三层次教学模式．以此强化学生思维能力的训练,从而提高教与学的效果。     

几种量子程序终止的有效验证

基于文献巨18口提出的量子程序验证方法,讨论了单量子比特系统上比特翻转、去极化、幅值阻尼、相位阻尼等 信道刻画的量子程序的验证,通过选取不同的可观测算子对程序终止的情况进行了详细的讨论。研究表明,由这些量 子信道所描述的量子程序的终止情况不仅依赖于输入态的选取,还依赖于可观测算子的选取。     

Self-generating program specializers

This paper demonstrates the existence of self-generating program specializers and uses a language-independent projection to obtain them. The projection is considered from the viewpoint of the interpretive approach and a bootstrapping technique is identified by which a specializer can optimize its own implementation. A theorem is presented that equates the set of self-generating specializers and the set of specializers produced by the new projection. A practical consequence of the theorem is that an implementation of a specializer must contain an error if it is not possible to observe self-generation, which requires only a textual program comparison. Self-generation may thus provide a method for testing specializers and self-interpreters while they are under development.     

A family of code coverage-based heuristics for effective fault localization

Locating faults in a program can be very time-consuming and arduous, and therefore, there is an increased demand for automated techniques that can assist in the fault localization process. In this paper a code coverage-based method with a family of heuristics is proposed in order to prioritize suspicious code according to its likelihood of containing program bugs. Highly suspicious code (i.e., code that is more likely to contain a bug) should be examined before code that is relatively less suspicious; and in this manner programmers can identify and repair faulty code more efficiently and effectively. We also address two important issues: first, how can each additional failed test case aid in locating program faults; and second, how can each additional successful test case help in locating program faults. We propose that with respect to a piece of code, the contribution of the first failed test case that executes it in computing its likelihood of containing a bug is larger than or equal to that of the second failed test case that executes it, which in turn is larger than or equal to that of the third failed test case that executes it, and so on. This principle is also applied to the contribution provided by successful test cases that execute the piece of code. A tool, χDebug, was implemented to automate the computation of the suspiciousness of the code and the subsequent prioritization of suspicious code for locating program faults. To validate our method case studies were performed on six sets of programs: Siemens suite, Unix suite, space, grep, gzip, and make. Data collected from the studies are supportive of the above claim and also suggest Heuristics III(a), (b) and (c) of our method can effectively reduce the effort spent on fault localization.