A Replicated Experiment to Assess Requirements Inspection Techniques

This paper presents the independent replication of a controlled experiment which compared three defect detection techniques (Ad Hoc, Checklist, and Defect-based Scenario) for software requirements inspections, and evaluated the benefits of collection meetings after individual reviews. The results of our replication were partially different from those of the original experiment. Unlike the original experiment, we did not find any empirical evidence of better performance when using scenarios. To explain these negative findings we provide a list of hypotheses. On the other hand, the replication confirmed one result of the original experiment: the defect detection rate is not improved by collection meetings.The independent replication was made possible by the existence of an experimental kit provided by the original investigators. We discuss what difficulties we encountered in applying the package to our environment, as a result of different cultures and skills. Using our results, experience and suggestions, other researchers will be able to improve the original experimental design before attempting further replications.     

Comparing Detection Methods For Software Requirements Inspections: A Replication Using Professional Subjects

Software requirements specifications (SRS) are often validated manually. One such process is inspection, in which several reviewers independently analyze all or part of the specification and search for faults. These faults are then collected at a meeting of the reviewers and author(s).Usually, reviewers use Ad Hoc or Checklist methods to uncover faults. These methods force all reviewers to rely on nonsystematic techniques to search for a wide variety of faults. We hypothesize that a Scenario-based method, in which each reviewer uses different, systematic techniques to search for different, specific classes of faults, will have a significantly higher success rate.In previous work we evaluated this hypothesis using 48 graduate students in computer science as subjects.We now have replicated this experiment using 18 professional developers from Lucent Technologies as subjects. Our goals were to (1) extend the external credibility of our results by studying professional developers, and to (2) compare the performances of professionals with that of the graduate students to better understand how generalizable the results of the less expensive student experiments were.For each inspection we performed four measurements: (1) individual fault detection rate, (2) team fault detection rate, (3) percentage of faults first identified at the collection meeting (meeting gain rate), and (4) percentage of faults first identified by an individual, but never reported at the collection meeting (meeting loss rate).For both the professionals and the students the experimental results are that (1) the Scenario method had a higher fault detection rate than either Ad Hoc or Checklist methods, (2) Checklist reviewers were no more effective than Ad Hoc reviewers, (3) Collection meetings produced no net improvement in the fault, and detection rate—meeting gains were offset by meeting losses,Finally, although specific measures differed between the professional and student populations, the outcomes of almost all statistical tests were identical. This suggests that the graduate students provided an adequate model of the professional population and that the much greater expense of conducting studies with professionals may not always be required.     

软件项目中需求管理的探索与实践

软件需求在软件产品的整个生命周期中占有十分重要的位置,对后续的软件开发和维护的成败具有决定性意义。在实践中,需求管理却往往得不到足够的重视。从软件需求和需求工程的概念入手,分析了软件需求管理中存在的内部与外部问题,并着重介绍了需求开发和管理的有效方法,提出了简单可行的需求分析评价标准。     

An Externally Replicated Experiment for Evaluating the Learning Effectiveness of Using Simulations in Software Project Management Education

The increasing demand for software project managers in industry requires strategies for the development of the management-related knowledge and skills of the current and future software workforce. Although several approaches help teach the required skills in a university setting, few empirical studies are currently available to characterize and compare their effects. This paper presents results of an externally replicated controlled experiment that evaluates the learning effectiveness of using a process simulation model for educating computer science students in software project management. While the experimental group applies a system dynamics (SD) simulation model, the control group uses the well-known COCOMO model as a predictive tool for project planning. The results of the empirical study indicate that students using the simulation model gain a better understanding about typical behavior patterns of software development projects. The combination of the results from the initial experiment and the replication corroborates this finding. Additional analysis shows that the observed effect can mainly be attributed to the use of the simulation model in combination with a web-based role-play scenario. This finding is strongly supported by information gathered from the debriefing questionnaires of subjects in the experimental group. They consistently rated the simulation-based role-play scenario as a very useful approach for learning about issues in software project management.     

An Empirically-Based Process for Software Architecture Evaluation

Software systems undergo constant change causing the architecture of the system to degenerate over time. Reversing system degeneration takes extra effort and delays the release of the next version. Improved architecture is intangible and does not translate into visible user features that can be marketed. Due to a lack of representative metrics, technical staff has problems arguing that stopping degeneration is indeed necessary and that the effort will result in an improved architecture that will pay off. We believe that architectural metrics would give technical staff better tools to demonstrate that the architecture has improved. This paper defines and uses a set of architectural metrics and outlines a process for analyzing architecture to support such an argument. The paper reports on a case study from a project where we restructured the architecture of an existing client-server system written in Java while adding new functionality. The modules of the existing version of the system were library-oriented and had a disorganized communication structure. The new architecture is based on components and utilizes the mediator design pattern. The goal of the study is to evaluate the new architecture from a maintainability perspective. The paper describes our evaluation process, the metrics used, and provides some preliminary results. The architectural evaluation shows that the components of the system are only loosely coupled to each other and that an architectural improvement has occurred from a maintenance perspective. The process used to evaluate the architecture is general and can be reused in other contexts.     

An Experimental Evaluation of an Experience-Based Capture-Recapture Method in Software Code Inspections

In order to improve the efficiency of inspections, quantitative data on defect content have to be the basis for decisions in the inspection process. An experience-based capture-recapture method is proposed, which overcomes some problems with the basic pre-requisites of the original method. A C-code inspection experiment is conducted to evaluate the enhanced method and its applicability to software code inspections. It is concluded that the experience-based estimation procedure gives significantly better estimates than the maximum-likelihood method and the estimates are not very sensitive to changes in the inspection data.     

A Replicated Empirical Study of the Impact of the Methods in the PSP on Individual Engineers

The Personal Software Process (PSP) has during the last couple ofyears gained attention as a way to individual improvements insoftware development. The PSP is introduced to students and engineersthrough a course, which introduces a personal software developmentprocess. The personal software development process is improvedin steps during the course and a collection of methods is introducedto support the personal development process. The question is,however, how do these methods influence the performance of anindividual engineer? This question has been studied in a studymade at the Software Engineering Institute, and the study hasshown that the methods in the PSP have a positive effect on theperformance of the individuals. There is however a need to replicatethis study to confirm the findings in other settings and withother individuals. This paper describes a replicationof the study made at the Software Engineering Institute. Boththe original study and this replication are made on data reportedfrom the students taking the PSP course. The differences betweenthe two studies are the programming languages used, which heldthe courses, the class sizes, and the experiences of the students.In summary, the results from this replication confirm the resultsin the original study: Size estimation accuracy gets better,the defect density gets lower, the defects are found earlierand that the pre-compile yield gets better during the PSP course.Basically, the two studies show that the methods in the PSP helpengineers to improve their performance.     

Empirical Evaluations of Usage-Based Reading and Fault Content Estimation for Software Inspections

This thesis describes six empirical investigations of two techniques applied to software inspections, namely reading techniques and fault content estimation techniques. The first part of the thesis presents a series of experiments of a novel reading technique called usage-based reading. The second part investigates fault content estimation applied to the software inspection process. The estimation methods used are capture-recapture and curve fitting.     

Comparison of Extended Jacobian and Lagrange Multiplier Based Methods for Resolving Kinematic Redundancy

Several methods have been proposed in the past for resolving the control of kinematically redundant manipulators by optimizing a secondary criterion. The extended Jacobian method constrains the gradient of this criterion to be in the null space of the Jacobian matrix, while the Lagrange multiplier method represents the gradient as being in the row space. In this paper, a numerically efficient form of the Lagrange multiplier method is presented and is compared analytically, computationally, and operationally to the extended Jacobian method. This paper also presents an improved method for tracking algorithmic singularities over previous work.     

键盘键入信号软件处理方法探讨

分析了常见的几种键入信号软件处理方式的基本工作原理 ,并根据系统的不同使用要求分几种情况详细讨论了键入信号的具体软件处理方法。     

一种软件构件的非功能属性量化评价方法

针对软件构件的非功能属性因具有模糊性而难以量化评价的问题,提出了一种群决策多指标模糊评价方法。该方法通过分析构件的非功能属性的分层度量指标,将层次分析法应用于指标的权重计算以减少人为因素的干扰,利用群决策获取模糊评价矩阵,给出指标语气算子的对应数值以便真实和贴切地反映评价意图;引入模糊集重心概念,把以模糊数表示的综合评价结果转换为明晰数,以利于构件的选择与排序。最后,给出了应用实例,验证了方法的有效性。     

离散元法工程计算软件的前后处理系统

本文介绍了我们为离散元法工程计算软件编制的前后图形处理系统的技术路线和主要方法。该系统以人机交互的方式实现了建模、数据传输和演示等全过程,界面操作简单直观,便于掌握和运用。     

高校专业化与职业化软件人才培养方法探析

探讨了软件行业对人才专业化与职业化的基本要求,分析了软件科学的特征与人才培养趋向,探析了高校专业化与职业化软件人才培养方法。提出了加强软件师资队伍建设,构建高素质的具有职业特征的软件师资队伍,加快课程设置更新的建议。好的人才培养理念和人才培养方法,是现行高校培养专业化与职业化软件人才的重要前提与保证。     

Software for an air pollution measuring system: An application of modula

The program for a small embedded computer system has been implemented in Modula. The execution speed of this program was particularly important and the speed achieved was adequate. Some parts of this program are described using a notation derived from the Mascot approach. The use of the Mascot notation with a module-structured language is discussed and some suggestions for an appropriate style are made. Some simple optimizations of the program were made in order to achieve increased execution speed and it was observed that the final program ran at about twenty times the rate of an equivalent Fortran program. Some points on the suitability of Modula are briefly discussed and, in a similar way to previous authors, it is concluded that Modula is suitable for applications of this type.     

应用模糊分析法对评价网络信息安全的有效研究

如今网络的普及率令人惊叹,然而由于非法入侵所造成的信息安全隐患时时刻刻都存在着.为了尽量降低非法入侵给网络带来的损害并避免此类安全隐患,如今研发出了一种名为模糊层次分析法的网络安全态势评估模型,首先完成对网络安全指标体系的构建,运用参差分析法对计算机各评估指标进行权重和分析.最后采用模糊分析法来建立一个网络信息安全态势一致性评判标准,最终达到综合评估网络信息安全态势的目的.相关研究结果表明,这种模糊层次分析法能够在很大程度上提升网络信息安全态势评估的准确度,结果更加精确而客观,实用性很强.文章旨在对网络信息安全评估的问题进行研究.     

分析国外信息基础设施关键性评价方法审视我国等级保护定级工作

文章通过分析比较关键信息基础设施保护对象与中国等级保护对象,研究国际基础设施关键性评价方法,反思中国等级保护定级理论和工作方法,提出了进一步改进等级保护定级工作对策和建议。     

An evaluation of semantic fisheye views for opportunistic search in an annotated image collection

Visual interfaces are potentially powerful tools for users to explore a representation of a collection and opportunistically discover information that will guide them toward relevant documents. Semantic fisheye views (SFEVs) are focus + context visualization techniques that manage visual complexity by selectively emphasizing and increasing the detail of information related to the users focus and deemphasizing or filtering less important information.In this paper we describe a prototype for visualizing an annotated image collection and an experiment to compare the effectiveness of two distinctly different SFEVs for a complex opportunistic search task. The first SFEV calculates relevance based on keyword-content similarity and the second based on conceptual relationships between images derived using WordNet. The results of the experiment suggest that semantic-guided search is significantly more effective than similarity-guided search for discovering and using domain knowledge in a collection.     

Algorithmic Foundations of Creation of an Intelligent Software Tool for Investigation and Solution of Cauchy Problems for Systems of Ordinary Differential Equations

Methods are proposed for computer investigation of properties of systems of ordinary differential equations. Based on these methods, algorithms are created for computation of the value of the integration step that provides the stability of a numerical method and obtaining its results with a preassigned accuracy. The components and modes of operation of an intelligent software tool supporting the proposed methods are presented.     

An extension of fuzzy TOPSIS for a group decision making with an application to tehran stock exchange

In financial markets, investors attempt to maximize their profits within a constructed portfolio with the aim of optimizing the tradeoffs between risk and return across the many stocks. This requires proper handling of conflicting factors, which can benefit from the domain of multiple criteria decision making (MCDM). However, the indexes and factors representing the stock performance are often imprecise or vague and this should be represented by linguistic terms characterized by fuzzy numbers. The aim of this research is to first develop three group MCDM methods, then use them for selecting undervalued stocks by dint of financial ratios and subjective judgments of experts. This study proposes three versions of fuzzy TOPSIS (Technique for Order Preference by Similarity to Ideal Solution): conventional TOPSIS (C-TOPSIS), adjusted TOPSIS (A-TOPSIS) and modified TOPSIS (M-TOPSIS) where a new fuzzy distance measure, derived from the confidence level of the experts and fuzzy performance ratings have been included in the proposed methods. The practical aspects of the proposed methods are demonstrated through a case study in the Tehran stock exchange (TSE), which is timely given the need for investors to select undervalued stocks in untapped markets in the anticipation of easing economic sanctions from a change in recent government leadership.