Intranet／Extranet的安全技术

分析了Intranet/Extranet所面临的安全性问题,介绍了加密技术、信息完整性技术,鉴别交换技术、确认技术、入侵检测技术及访问控制技术等六种基本的安全技术,最后给出一个实例。     

A methodology for the selection of requirements engineering techniques

The complexity of software projects as well as the multidisciplinary nature of requirements engineering (RE) requires developers to carefully select RE techniques and practices during software development. Nevertheless, the selection of RE techniques is usually based on personal preference or existing company practice rather than on characteristics of the project at hand. Furthermore, there is a lack of guidance on which techniques are suitable for a certain project context. So far, only a limited amount of research has been done regarding the selection of RE techniques based on the attributes of the project under development. The few approaches that currently exist for the selection of RE techniques provide only little guidance for the actual selection process. We believe that the evaluation of RE techniques in the context of an application domain and a specific project is of great importance. This paper describes a Methodology for Requirements Engineering Techniques Selection (MRETS) as an approach that helps requirements engineers select suitable RE techniques for the project at hand. The MRETS has three aspects: Firstly, it aids requirements engineers in establishing a link between the attributes of the project and the attributes of RE techniques. Secondly, based on the evaluation schema proposed in our research, MRETS provides an opportunity to analyze RE techniques in detail using clustering. Thirdly, the objective function used in our approach provides an effective decision support mechanism for the selection of RE techniques. This paper makes contributions to RE techniques analysis, the application of RE techniques in practice, RE research, and software engineering in general. The application of the proposed methodology to an industrial project provides preliminary information on the effectiveness of MRETS for the selection of RE techniques.     

无线传感器网络的研究进展

随着传感器技术、嵌入式计算技术、分布式信息处理技术和通信技术的迅速发展,无线传感器网络应运而生.由于无线传感器网络的广阔应用前景,它已经成为21世纪的一个新研究领域,在基础理论和工程技术两个层面向科技工作者提出了大量挑战性问题.从2000年开始,国内外无线传感器网络的研究日趋热烈,取得了大量研究成果.从无线传感器网络的网络通信技术、基础设施技术、中间件技术、数据管理技术、节点及其嵌入式软件技术等5个方面系统综述了无线传感器网络的研究进展,讨论目前存在的问题和需要进一步研究的方向,并提供了广泛的参考文献.     

The sorting techniques: a tutorial paper on card sorts, picture sorts and item sorts

Although sorting techniques (e.g. card sorts) are widely used in knowledge acquisition and requirements acquisition, they have received little formal attention compared to related techniques such as repertory grids and laddering. This paper briefly describes the main sorting techniques, then provides a detailed tutorial on one variety (repeated single-criterion sorts), using a worked example. Guidelines for choice and sequencing of techniques are given, both in relation to varieties of sorting technique and in relation to other techniques. It is concluded that the sorting techniques are a valuable part of the elicitor's methodological toolkit.     

K-DT: a formal system for the evaluation of linear data dependence testing techniques

The power of data dependence testing techniques of a parallelizing compiler is its essence to transform and optimize programs. Numerous techniques were proposed in the past, and it is, however, still a challenging problem to evaluate the relative power of these techniques to better understand the data dependence testing problem. In the past, either empirical studies or experimental evaluation results are published to compare these data dependence testing techniques, being not able to convince the research community completely. In this paper, we show a theoretical study on this issue, comparing the power on disproving dependences of existing techniques by proving theorems in a proposed formal system K-DT. Besides, we also present the upper bounds of these techniques and introduce their minimum complete sets. To the best of our knowledge, K-DT is the first formal system used to compare the power of data dependence testing techniques, and this paper is the first work to show the upper bounds and minimum complete sets of data dependence testing techniques.     

Application of decision-making techniques in supplier selection: A systematic review of literature

Despite the importance of decision-making (DM) techniques for construction of effective decision models for supplier selection, there is a lack of a systematic literature review for it. This paper provides a systematic literature review on articles published from 2008 to 2012 on the application of DM techniques for supplier selection. By using a methodological decision analysis in four aspects including decision problems, decision makers, decision environments, and decision approaches, we finally selected and reviewed 123 journal articles. To examine the research trend on uncertain supplier selection, these articles are roughly classified into seven categories according to different uncertainties. Under such classification framework, 26 DM techniques are identified from three perspectives: (1) Multicriteria decision making (MCDM) techniques, (2) Mathematical programming (MP) techniques, and (3) Artificial intelligence (AI) techniques. We reviewed each of the 26 techniques and analyzed the means of integrating these techniques for supplier selection. Our survey provides the recommendation for future research and facilitates knowledge accumulation and creation concerning the application of DM techniques in supplier selection.     

Analyzing regression test selection techniques

Regression testing is a necessary but expensive maintenance activity aimed at showing that code has not been adversely affected by changes. Regression test selection techniques reuse tests from an existing test suite to test a modified program. Many regression test selection techniques have been proposed, however, it is difficult to compare and evaluate these techniques because they have different goals. This paper outlines the issues relevant to regression test selection techniques, and uses these issues as the basis for a framework within which to evaluate the techniques. The paper illustrates the application of the framework by using it to evaluate existing regression test selection techniques. The evaluation reveals the strengths and weaknesses of existing techniques, and highlights some problems that future work in this area should address     

Improving data perturbation testing techniques for Web services

The widespread use of service-oriented architectures (SOAs) and Web services in commercial software requires the adoption of development techniques to ensure the quality of Web services. Testing techniques and tools concern quality and play a critical role in accomplishing quality of SOA based systems. Existing techniques and tools for traditional systems are not appropriate to these new systems, making the development of Web services testing techniques and tools required. This article presents new testing techniques to automatically generate a set of test cases and data for Web services. The techniques presented here explore data perturbation of Web services messages upon data types, integrity and consistency. To support these techniques, a tool (GenAutoWS) was developed and applied to real problems.     

The sorting techniques: a tutorial paper on card sorts, picture sorts and item sorts

Abstract: Although sorting techniques (e.g. card sorts) are widely used in knowledge acquisition and requirements acquisition, they have received little formal attention compared to related techniques such as repertory grids and laddering. This paper briefly describes the main sorting techniques, and then provides a detailed tutorial on one variety (repeated single‐criterion sorts), using a worked example. Guidelines for choice and sequencing of techniques are given, both in relation to varieties of sorting technique and in relation to other techniques. It is concluded that the sorting techniques are a valuable part of the elicitor's methodological toolkit.     

小波域视频运动估计研究进展

小波域运动估计技术作为基于小波的视频编码器中最关键的技术之一,成为近年来研究的热点．文章首先对比论述了空间域运动估计技术的不足和小波域运动估计技术的优势,然后以小波域运动估计技术的发展为主线,将目前的研究方法归纳为三类：对子带直接运动估计技术、子带间接运动估计技术和克服平移可变性的运动估计技术,并对三类运动估计方法的发展进行了概括性阐述和比较性研究,对三类方法中各种算法的适用范围、优势和所存在的问题进行了深入的讨论,在此基础上对小波域运动估计技术的未来发展趋势进行了展望．     

Evaluation of illustration‐inspired techniques for time‐varying data visualization

Illustration‐inspired techniques have provided alternative ways to visualize time‐varying data. Techniques such as speedlines, flow ribbons, strobe silhouettes and opacity‐based techniques provide temporal context to the current timestep being visualized. We evaluated the effectiveness of these illustrative techniques by conducting a user study. We compared the ability of subjects to visually track features using snapshots, snapshots augmented by illustration techniques, animations, and animations augmented by illustration techniques. User accuracy, time required to perform a task, and user confidence were used as measures to evaluate the techniques. The results indicate that the use of illustration‐inspired techniques provides a significant improvement in user accuracy and the time required to complete the task. Subjects performed significantly better on each metric when using augmented animations as compared to augmented snapshots.     

Sampling and node adding in probabilistic roadmap planners

The probabilistic roadmap approach is one of the leading motion planning techniques. Over the past decade the technique has been studied by many different researchers. This has led to a large number of variants of the approach, each with its own merits. It is difficult to compare the different techniques because they were tested on different types of scenes, using different underlying libraries, implemented by different people on different machines. In this paper we provide a comparative study of a number of these techniques, all implemented in a single system and run on the same test scenes and on the same computer. In particular we compare collision checking techniques, sampling techniques, and node adding techniques. The results were surprising in the sense that techniques often performed differently than claimed by the designers. The study also showed how difficult it is to evaluate the quality of the techniques. The results should help future users of the probabilistic roadmap planning approach in deciding which technique is suitable for their situation.     

基于压缩域的图像检索技术

图像检索技术是多媒体应用中的关键技术，现有的基于内容图像检索技术大都是基于非压缩域的，对于目前普遍存在的压缩格式图像，采用这种技术必须先解压再检索，不但计算量大，而且需占用较多的中介存储空间，所以严重影响了检索系统的实时性和灵活性，同时各种压缩标准(如JPEG，MPEG，JPEG2000等)的推出与普及也促使人们寻求可以直接在压缩域操作的检索技术，该文对现有的压缩域图像检索技术的发展进行综述，并讨论了未来可能的研究方向。     

Knowledge representation and processing in economics and management

Various techniques for computer-based knowledge representation and processing are widely used in management and economics. Other techniques such as rules and demons have arisen in the artificial intelligence field. These too can be useful in managerial and economics settings. A major issue is how to effectively employ multiple traditional and artificial intelligence techniques when working on a problem. In this paper, we examine the various knowledge management techniques with respect to their applicability to handling distinct types of knowledge. An object-oriented framework is presented as a basis for the unified and coordinated treatment of multiple knowledge management techniques in a single environment. Using this framework, two approaches are identified for delivering these techniques to a knowledge worker: skeletal environments and furnished environments.     

Designing pixel-oriented visualization techniques: theory andapplications

Visualization techniques are of increasing importance in exploring and analyzing large amounts of multidimensional information. One important class of visualization techniques which is particularly interesting for visualizing very large multidimensional data sets is the class of pixel-oriented techniques. The basic idea of pixel-oriented visualization techniques is to represent as many data objects as possible on the screen at the same time by mapping each data value to a pixel of the screen and arranging the pixels adequately. A number of different pixel-oriented visualization techniques have been proposed in recent years and it has been shown that the techniques are useful for visual data exploration in a number of different application contexts. In this paper, we discuss a number of issues which are important in developing pixel-oriented visualization techniques. The major goal of this article is to provide a formal basis of pixel-oriented visualization techniques and show that the design decisions in developing them can be seen as solutions of well-defined optimization problems. This is true for the mapping of the data values to colors, the arrangement of pixels inside the subwindows, the shape of the subwindows, and the ordering of the dimension subwindows. The paper also discusses the design issues of special variants of pixel-oriented techniques for visualizing large spatial data sets     

Induction as the Basis for Program Verification

We will consider the inductive mechanisms in five techniques for verifying iterative/recursive program structures: inductive assertion, predicate transformers, subgoal induction, computation induction, and structural induction. We will discover that all five techniques can be justified by a single theorem about inductive proof techniques. We will also show that all five techniques face the problem of finding properties that will carry an induction. Such properties are called inductive sets. We will see that the inductive sets of the five techniques are easily related to one another and that a program proof by any of the techniques can be easily converted to a proof by any of the other techniques. Our conclusion is that computer programs simply are inductive definitions of the functions they compute. Induction is the only method by which they can be proved. The problems of induction are therefore unavoidable.     

面向主体的系统开发方法

面向主体的技术是分析、设计和实现分布式信息系统的一种新方法。本文详细地介绍了利用主体技术进行系统分析、设计、实现、规范、验证的技术和方法，最后讨论了应用此方法和技术应注意的问题。     

自由立体显示技术及其发展

自由立体显示技术是指不需佩戴立体眼镜等附属设备的3维立体显示技术.它可分为全息立体技术、3维集成成像技术、体3维显示技术和基于视差的自由立体显示技术.其中体3维显示技术和基于水平视差的自由立体技术发展很快.本文首先论述了静态体3维显示技术和扫射体3维显示技术两类不同的体3维显示技术近几年来的研究进展;然后从所使用的光学光栅类型及复用方法上综述了基于视差的自由立体显示技术的现状和特点;最后对比了体3维显示技术和基于水平视差的自由立体技术优缺点.     

数字图像反取证技术综述

目的 数字图像的真实性问题备受人们关注,被动取证是解决该问题的有效途径。然而,如果伪造者在篡改图像的同时利用反取证技术对篡改的痕迹进行消除或伪造,那么已有的大量被动取证技术都将失效。回顾图像反取证技术的研究现状（包括兴起原因、实现原理、技术特点以及应用前景）,并根据已有文献总结反取证技术面临的主要挑战和机遇。方法 由于现有的被动取证技术大都基于遗留痕迹和固有特征的异同来辨识图像真伪,因此本文以不同的取证特征为线索来评述和比较反取证技术的原理和策略。结果 根据取证特征的不同,将反取证技术归纳为遗留痕迹隐藏、固有特征伪造和反取证检测等三类,并展示了当前各类反取证技术面临的难点和挑战。结论 对数字图像反取证技术进行总结和展望,并指出其算法未来在通用性、安全性、可靠性等方面将有待进一步的深入研究。     

基于QNX的舰艇控制系统双机容错设计

容错技术是保障舰艇控制系统可靠运行的重要技术,在分析基于QNX操作系统的舰艇中央控制系统的基础上,讨论了基于硬件方法和软件方法的双机冗余容错技术的实现,着重分析了以太网容错的实现方法。