一种精确程序最坏执行时间分析方法

Java语言的动态特性使程序的最坏执行时间分析较悲观和难以预测,提出一种精确最坏执行时间分析方法,在高层分析中,引入一种标记方法,对带有标记的Java类文件进行反编译提取控制流程,得到每一个基本块中的Java 字节码指令的最坏情况下的执行次数,在底层分析中,建立结合流水线和高级缓存影响的时间模型,得到每条指令所对应的执行时间,最后结合高层分析和底层分析的结果得到程序的最坏情况下的执行时间。实验表明,该方法可以使对实时Java 程序的最坏情况执行时间预测更加安全和精确。     

Updating Fortran programs and other legacy code to an interactive window platform

This paper introduces a hybrid method to update legacy programs, thus combining the visual interactivity of window programs with the qualities of legacy code. Because migration from C, Fortran or Pascal to another programming language is very time-consuming and error-prone, it can be more beneficial to integrate legacy executable files into a visual interactive window shell. Such a shell program is described in this work. Its main part is a multi-file manager with an executable file as the main building block and MyFile as the base class of the resulting UML model. The window shell chosen here runs under the Microsoft Windows 9x/NT/2k/XP operating systems, and the program language to implement the designed shell is Visual Basic. The final shell program was tested with different types of executable files for earth satellite orbit determination, tidal acceleration computation and deformation analysis.     

基于证据推理的程序恶意性判定方法

针对可执行程序恶意性难以判定的情况,提出一种基于证据推理的程序恶意性判定方法.首先,建立程序恶意性判定模型;然后,通过对程序进行反编译,抽取影响程序安全性的特征,建立程序行为集合;使用BP神经网络对模型进行训练得到各个行为的概率分配函数BPAF(basic probability assignment functions),并使用加权和形式的合成法则对程序行为进行合成;最后,实现对程序恶意性的判定.实验结果表明了该方法的有效性.     

通过自学习生成库函数识别模板库

库函数识别是反编译中的重要的环节，也是难点之一。成功地识别库函数，不仅有利于反编译后继阶段的实现，而且对用户阅读理解反编译生成的高级语言程序大有助益。实现库函数识别，最困难的是为各种编译系统各个版本各种模式的库函数分别构造库函数识别模板库，这是工作量很大的任务。本文介绍了ＤＥＣＬＥＲ中所采用的通过自学习生成模板库的方法。该方法减轻了库函数识别模板库的工作量并降低了技术难度。该技术和工具将向用户开放     

基于积件思想的高职计算机课程项目式教学探索——以C语言程序设计为例

基于积件思想,对五年制高职计算机课程项目式教学进行探索,以C语言程序设计为例研究分析,并组建C语言程序设计课程知识点积件库,编写高职C语言程序设计课程项目式校本教材,分析C语言程序设计课程教学项目“阶梯电价计费”.并借助开源平台Moodle实现了教学项目的应用.     

基于VC++和Prolog语言混合编程的专家系统框架

为解决专家系统开发周期长的问题,提出并实现了用PROLOG与VC 混合编程方法开发专家系统框架的方案,用VC 实现专家系统框架的人机界面,用PROLOG语言构建知识库并实现推理过程.该框架具有较好的用户界面,用户只要输入或导入脚本编写的知识库、事实库和目标,就可以进行目标求解,因此简化了专家系统的开发过程.介绍了该专家系统框架的实现原理和设计思想,给出了导入导出模块、脚本语言语法检测模块和解释机制的实现方法.     

Data communication between an expert system shell and a conventional algorithmic program with application to cam motion specification

Although more and more expert system shells have begun to provide communication interfaces to conventional procedural languages, the interfaces are basically shell- and language-dependent. This paper presents a simple, shell- and language-independent data communication technique between a shell and a procedural language via a concept analogous to the handshake data transmission used in microprocessors. A control file is used for the action of handshake. The communication interface is between two data files in two different language environments. A program written in a LISP-based expert system shell, OPS 5, and one written in a procedural language, FORTRAN, were tested to verify the presented technique.An expert system for cam motion specification, which needs the following three tasks—symbolic representation, numerical computation, and their communication—is described as one of the possible applications of the technique. These three tasks are essential to automated engineering design and analysis.     

基于动静结合的Android恶意代码行为相似性检测

针对同种族恶意软件行为具有相似性的特点进行研究,提出通过静态分析和动态运行程序相结合的方式度量软件行为的相似性。通过反编译和soot代码转换框架获取程序控制流图,利用行为子图匹配算法从静态方面对程序行为相似性进行度量;通过自动化测试框架运行程序,利用文本无关压缩算法将捕获到的trace文件压缩后进行相似性度量。该检测方法综合静态检测执行效率高和动态检测准确率高的优点,实验分析表明,该检测技术能够准确度量程序之间行为的相似性,在准确率上相较于Androidguard有大幅提升。     

Reasoning about programs

This paper describes a theorem prover that embodies knowledge about programming constructs, such as numbers, arrays, lists, and expressions. The program can reason about these concepts and is used as part of a program verification system that uses the Floyd-Naur explication of program semantics. It is implemented in the qa4 language; the qa4 system allows many pieces of strategic knowledge, each expressed as a small program, to be coordinated so that a program stands forward when it is relevant to the problem at hand. The language allows clear, concise representation of this sort of knowledge. The qa4 system also has special facilities for dealing with commutative functions, ordering relations, and equivalence relations; these features are heavily used in this deductive system. The program interrogates the user and asks his advice in the course of a proof. Verifications have been found for Hoare's FIND program, a real-number division algorithm, and some sort programs, as well as for many simpler algorithms. Additional theorems have been proved about a pattern matcher and a version of Robinson's unification algorithm. The appendix contains a complete, annotated listing of the deductive system and annotated traces of several of the deductions performed by the system.     

RAPS: a rule-based language for specifying resource allocation andtime-tabling problems

A general language for specifying resource allocation and time-tabling problems is presented. The language is based on an expert system paradigm that was developed previously by the authors and that enables the solution of resource allocation problems by using experts' knowledge and heuristics. The language enables the specification of a problem in terms of resources, activities, allocation rules, and constraints, and thus provides a convenient knowledge acquisition tool. The language syntax is powerful and allows the specification of rules and constraints that are very difficult to formulate with traditional approaches, and it also supports the specification of various control and backtracking strategies. We constructed a generalized inference engine that runs compiled resource allocation problem specification language (RAPS) programs and provides all necessary control structures. This engine acts as an expert system shell and is called expert system for resource allocation (ESRA). The performance of RAPS combined with ESRA is demonstrated by analyzing its solution of a typical resource allocation problem     

Propositional representation for graphical knowledge

Multi-media interfaces with a graphics and a natural language component can be viewed as a Natural Language Graphics systems without a host program. We will investigate a theory of Natural Language Graphics that is based on the notion of “Graphical Deep Knowledge” defined in this research. Graphical Deep Knowledge is knowledge that can be used for display purposes as well as reasoning purposes and we describe the syntax and semantics of its constructs. This analysis covers forms, positions, attributes, parts, classes, reference frames, inheritability, etc. Part hierarchies are differentiated into three sub-types. The usefulness of inheritance along part hierarchies is demonstrated, and criticism of inheritance-based knowledge representation formalisms with a bias towards class hierarchies is derived from this finding. The presented theory has been implemented as a generator program that creates pictures from knowledge structures, and as an augmented transition network grammar that creates knowledge structures from limited natural language input. The function of the picture generation program Tina as a user interface for a circuit board maintenance system and as part of a CAD-like layout system is demonstrated.     

The Refinement Paradigm: The Interaction of Coding and Efficiency Knowledge in Program Synthesis

A refinement paradigm for implementing a high-level specification in a low-level target language is discussed. In this paradigm, coding and analysis knowledge work together to produce an efficient program in the target language. Since there are many possible implementations for a given specification of a program, searching knowledge is applied to increase the efficiency of the process of finding a good implementation. For example, analysis knowledge is applied to determine upper and lower cost bounds on alternate implementations, and these bounds are used to measure the potential impact of different design decisions and to decide which alternatives should be pursued. In this paper we also describe a particular implementation of this program synthesis paradigm, called PSI/SYN, that has automatically implemented a number of programs in the domain of symbolic processing.     

知识库系统KBASE＋的数据模型,语言及实现

本文讨论具有面向对象特征的知识库系统ＫＢＡＳＥ＋的数据模型，语言及实现，ＫＢＡＳＥ＋的数据模型可以方便地支持对象标识，类层次，多继承等面向对象概念。描述性查询语言ＫＢＬ是扩充的ＤＡＴＡＬＯＧ。本文重构了ＫＢＬ语义理论框架，提出了解决属性继承和实例继承的方案，说明了ＫＢＬ程序可以转换成语义等价的ＤＡＴＡＬＯＧ程序。     

UNIX系统C语言联机帮助系统的设计与实现

本文较详细地介绍了ＵＮＩＸ环境下Ｃ语言的联机帮助系统ｃｈｅｌｐ的设计与实现。该系统由一个辅助的ｓｈｅｌｌ程序和联机帮助系统自身构成。前者的作用在于加速系统的开发，使得在增删及修正帮助信息时系统的更新得以自动完成，后者包括各类帮助信息的正文，涉及ＡＮＳＩＣ与ＵＮＩＸＣ标准库函数的用法以及可被程序员任意剪裁的示例程序。     

Constructing and consulting the knowledge base of an expert systems shell

Abstract: This paper presents an expert system shell whose inference mechanism uses backward chaining. In particular the modules devoted to constructing and consulting the knowledge base are illustrated. The programming environment is based on the Arity-Prolog language, a popular Prolog dialect running on IBM PCs and compatibles.     

Expert system shells in student advising

A student advising expert system has been developed using the EXSYS Professional expert system shell. The motivation of using a commercially-available expert system shell is presented. Examples of IF-THEN-ELSE type of rules are shown. Interrelation of the knowledge base with class offerings, and with the structure of the B.Sc. program in Computer Science is demonstrated. The development process is described in detail. Improvements resulted from testing the system are presented.