Evolving complexity

A review of efforts to implement the process of evolution in a computational medium. The review will cover prominent examples, and discuss the major classes of implementations, their successes, and the obstacles they face. This work was presented, in part, at the International Symposium on Artificial Life and Robotics, Oita, Japan, February 18–20, 1996     

A Software-Optimized Encryption Algorithm

We describe the software-efficient encryption algorithm SEAL 3.0. Computational cost on a modern 32-bit processor is about 4 clock cycles per byte of text. The cipher is a pseudorandom function family: under control of a key (first preprocessed into an internal table) it stretches a 32-bit position index into a long, pseudorandom string. This string can be used as the keystream of a Vernam cipher. Received 3 May 1996 and revised 17 September 1997     

Experiment and numerical simulation of double-layered RC plates under impact loadings

This paper is to investigate and to propose a method to improve the impact resistance of reinforced concrete (RC) plates against projectile impact, and the damage of double-layered RC plates is examined experimentally and simulated analytically. In tests, a projectile launching apparatus, which is a 40 mm smooth-bore airgun, was used. Based on experimental results, numerical simulations with the DYNA-3D code, which takes account of the dynamic constitutive law of concrete, were done to find the applicability of the present computer code to the analysis of double-layered RC plates under high-speed impact loadings. In this study, the impact resistance of concrete plate is defined as the degree of local damage. In both experiments and numerical simulations, the effect of double-layering on the impact resistance is discussed.     

An empirical study of fine-grained software modifications

Software is typically improved and modified in small increments (we refer to each of these increments as a modification record—MR). MRs are usually stored in a configuration management or version control system and can be retrieved for analysis. In this study we retrieved the MRs from several mature open software projects. We then concentrated our analysis on those MRs that fix defects and provided heuristics to automatically classify them. We used the information in the MRs to visualize what files are changed at the same time, and who are the people who tend to modify certain files. We argue that these visualizations can be used to understand the development stage of in which a project is at a given time (new features are added, or defects are being fixed), the level of modularization of a project, and how developers might interact between each other and the source code of a system.     

采用Trimedia/Nexperia DSP的流结构模式实现G.723.1实时语音编解码

G．723．1协议是将音频信号压缩到5．3Kb／s和6．3Kb／s2种码率的音频编解码协议，主要应用在多媒体通信中的音频压缩。介绍一种基于Trimedia／Nexperia DSP的流结构TSSA(Trimedia Streaming Software Architecture)实现应用在可视电话中的G．723．1实时语音编解码。     

COMBINATORIAL DESIGN APPROACHES FOR AUTOMATIC TEST GENERATION

The n-way combination testing is a specification-based testing criterion, which requires that for a system consisted of a few parameters, every combination of valid values of arbitrary n(n ≥ 2) parameters be covered by at least one test. This letter proposed two different test generation algorithms based on combinatorial design for the n-way coverage criterion. The automatic test generators are implemented and some valuable empirical results are obtained.     

C语言反编译系统DECLER

本文对C语言反编译系统DECLER1．1性能、结构及实现技术给出介绍，并对反编译研究中存在的问题进行了讨论和分析。     

A group process for defining local software quality: Field applications and validation experiments

‘Global’ measures of software quality are generally not used by practitioners because they have not been calibrated for local operating environments. A participative process for defining local software quality has been defined, applied in the field, and evaluated in formal validation experiments. In four field applications of the process, a ‘jury’ of seasoned practitioners ranked a sample of modules from the organization's inventory of code and produced a ‘software quality rule set’. The results of each field application were tested in a formal validation experiment to determine whether the obtained rule set was a valid representation of the organization's sense of quality, i.e. whether the locally-derived rules could enable non-organizational programmers to make judgments about quality that were similar to those of the jury. In each experiment, non-organizational programmers ranked the same set of modules that were ranked by the organization's jury, using either the locally-derived rules, generic (textbook) rules, placebo (non-helpful) rules, or no rules. The correlation between the judgments of non-organizational programmers using local rules and the jury was statistically significant at p < 0–005; all other correlations were significant at p < 0–005. The results support a conclusion that the group process for defining local software quality is reliable in producing valid rule sets.     

基于UML语音发票查询系统的研究及应用

UML建模是面向对象技术的一个重要应用，也是近代软件工程环境中对象分析和设计的重要工具。本文首先介绍了UML的建模原理，然后结合海口地税语音发票查询系统项目的分析设计过程，对UML技术的具体应用作了详细的描述。