软件成本评估方法综述

如何做好软件项目预算一直是政府机关、企事业单位进行信息化建设的难题之一。软件成本评估是通过一套流程或模型对软件项目开发的工作量、工期和成本进行评估的行为,可以提高软件预算的精确度,有利于保障软件项目的交付周期,合理安排和调度研发人员。首先,对软件成本评估方法进行分类介绍和对比,分析其优缺点;然后,采用软件项目样本数据,对功能点、用例点、神经网络、类推4种评估方法进行实验分析;最后,指出现有的软件成本评估方法存在的问题和进一步研究的方向。     

MND-SCEMP: an empirical study of a software cost estimation modeling process in the defense domain

The primary focus of weapon systems research and development has moved from a hardware base to a software base and the cost of software development is increasing gradually. An accurate estimation of the cost of software development is now a very important task in the defense domain. However, existing models and tools for software cost estimation are not suitable for the defense domain due to problems of accuracy. Thus, it is necessary to develop cost estimation models that are appropriate to specific domains. Furthermore, most studies of methodology development are aligned with generic methodologies that do not consider the pertinent factors to specific domains, whereas new methodologies should reflect specific domains. In this study, we apply two generic methodologies to the development of a software cost estimation model, before suggesting an integrated modeling process specifically for the national defense domain. To validate our proposed modeling process, we performed an empirical study of 113 software development projects on weapon systems in Korea. A software cost estimation model was developed by applying the proposed modeling process. The MMRE value of this model was 0.566 while the accuracy was appropriate for use. We conclude that the modeling process and software cost estimation model developed in this study is suitable for estimating resource requirements during weapon system development in South Korea’s national defense domain. This modeling process and model may facilitate more accurate resource estimation by project planners, which will lead to more successful project execution.     

Factors affecting duration and effort estimation errors in software development projects

The purpose of this research was to fill a gap in the literature pertaining to the influence of project uncertainty and managerial factors on duration and effort estimation errors. Four dimensions were considered: project uncertainty, use of estimation development processes, use of estimation management processes, and the estimator’s experience. Correlation analysis and linear regression models were used to test the model and the hypotheses on the relations between the four dimensions and estimation errors, using a sample of 43 internal software development projects executed during the year 2002 in the IT division of a large government organization in Israel. Our findings indicate that, in general, a high level of uncertainty is associated with higher effort estimation errors while increased use of estimation development processes and estimation management processes, as well as greater estimator experience, are correlated with lower duration estimation errors. From a practical perspective, the specific findings of this study can be used as guidelines for better duration and effort estimation. Accounting for project uncertainty while managing expectations regarding estimate accuracy; investing more in detailed planning and selecting estimators based on the number of projects they have managed rather than their cumulative experience in project management, may reduce estimation errors.     

Improving the availability and cost-effectiveness of guidelines for guideline-users: towards a structured approach

The achievement of design and development solutions can be enhanced through consulting appropriate guidelines Although a wide range exist, frequently their full benefits are not realized by guideline-users because of the costs associated with their use. Guideline-users are people who use guidelines to support purposeful activity. Major cost drivers for guideline-users are the processes of 'selecting' appropriate guidelines and their subsequent 'translation' to an applied setting both of which can be prohibitively expensive. A strategy for producing guidelines is proposed, to minimize these costs, which is illustrated by the use of a case study concerned with the development of guidelines to assist in the production of management and administrative tools which will support project managers concerned with Human Factors Acceptance Testing. A process to support the assessment of guidelines is also proposed.     

A Study of Uncertainty in Software Cost and Its Impact on Optimal Software Release Time

For a development software project, management often faces the dilemma of when to stop testing the software and release it for operation, which requires careful decision-making as it has great impact on both software reliability and project cost. In most existing research on optimal software release problem, the cost considered was the expected cost (EC) of the project. However, what management concerns is the actual cost (AC) of the project rather than the EC. Treatment (such as minimization) of the EC may not ensure a desired low level of the AC, due to the uncertainty (variability) involved in the AC. In this paper, we study the uncertainty in software cost and its impact on optimal software release time in detail. The uncertainty is quantified by the variance of the AC and several risk functions. A risk-control approach to optimal software release problem is proposed. New formulations of the problem which are extensions of current formulations are developed, and solution procedures are established. Several examples are presented. Results reveal that it seems crucial to take account of the uncertainty in software cost in optimal software release problem, otherwise unsafe decision may be reached which could be a false dawn to management.     

Managing uncertainty in project portfolio cost estimation

Although typically a software development organisation is involved in more than one project simultaneously, the available tools in the area of software cost estimation deal mostly with single software projects. In order to calculate the possible cost of the entire project portfolio, one must combine the single project estimates taking into account the uncertainty involved. In this paper, statistical simulation techniques are used to calculate confidence intervals for the effort needed for a project portfolio. The overall approach is illustrated through the adaptation of the analogy-based method for software cost estimation to cover multiple projects.     

The Impact of Lessons-Learned Sessions on Effort Estimation and Uncertainty Assessments

Inaccurate estimates of software development effort is a frequently reported cause of IT-project failures. We report results from a study that investigated the effect of introducing lessons-learned sessions on estimation accuracy and the assessment of uncertainty. Twenty software professionals were randomly allocated to a Learning group or a Control group and instructed to estimate and complete the same five development tasks. Those in the Learning group but not those in the Control group were instructed to spend at least 30 minutes on identifying, analyzing, and summarizing their effort estimation and uncertainty assessment experience after completing each task. We found that the estimation accuracy and the realism of the uncertainty assessment were not better in the Learning group than in the Control group. A follow-up study with 83 software professionals was completed to better understand this lack of improvement from lessons-learned sessions. The follow-up study found that receiving feedback about other software professionals' estimation performance led to more realistic uncertainty assessments than receiving the same feedback of one's own estimates. Lessons-learned sessions, not only in estimation contexts, have to be carefully designed to avoid wasting resources on learning processes that stimulate rather than reduce learning biases.     

A flexible method to estimate the software development effort based on the classification of projects and localization of comparisons

The estimation of software development effort has been centralized mostly on the accuracy of estimates through dealing with heterogeneous datasets regardless of the fact that the software projects are inherently complex and uncertain. In particular, Analogy Based Estimation (ABE), as a widely accepted estimation method, suffers a great deal from the problem of inconsistent and non-normal datasets because it is a comparison-based method and the quality of comparisons strongly depends on the consistency of projects. In order to overcome this problem, prior studies have suggested the use of weighting methods, outlier elimination techniques and various types of soft computing methods. However the proposed methods have reduced the complexity and uncertainty of projects, the results are not still convincing and the methods are limited to a special domain of software projects, which causes the generalization of methods to be impossible. Localization of comparison and weighting processes through clustering of projects is the main idea behind this paper. A hybrid model is proposed in which the software projects are divided into several clusters based on key attributes (development type, organization type and development platform). A combination of ABE and Particle Swarm Optimization (PSO) algorithm is used to design a weighting system in which the project attributes of different clusters are given different weights. Instead of comparing a new project with all the historical projects, it is only compared with the projects located in the related clusters based on the common attributes. The proposed method was evaluated through three real datasets that include a total of 505 software projects. The performance of the proposed model was compared with other well-known estimation methods and the promising results showed that the proposed localization can considerably improve the accuracy of estimates. Besides the increase in accuracy, the results also certified that the proposed method is flexible enough to be used in a wide range of software projects.     

敏捷方法在软件项目开发中的实践

目前很多企业内中小型软件项目面临开发时间紧迫、人手不足、需求不断变化的困难,传统重量级的软件开发方法无法应对这样的挑战.敏捷方法是基于实践的软件开发方法学,为解决这类轻量级项目管理和开发所碰到的问题提供了新的思路.通过分析敏捷方法的主要目标、观点和原则,并结合一个实际的管理信息系统项目开发,从项目计划、项目文档、重构的改进和项目维护的4个方面探讨了敏捷方法的实践应用.实践证明,采用敏捷方法的观点和原则进行必要的改进,能取得项目开发的成功.     

IT Service Management Process Improvement based on ISO/IEC 15504: A systematic review

Context

In recent years, many software companies have considered Software Process Improvement (SPI) as essential for successful software development. These companies have also shown special interest in IT Service Management (ITSM). SPI standards have evolved to incorporate ITSM best practices.

Objective

This paper presents a systematic literature review of ITSM Process Improvement initiatives based on the ISO/IEC 15504 standard for process assessment and improvement.

Method

A systematic literature review based on the guidelines proposed by Kitchenham and the review protocol template developed by Biolchini et al. is performed.

Results

Twenty-eight relevant studies related to ITSM Process Improvement have been found. From the analysis of these studies, nine different ITSM Process Improvement initiatives have been detected. Seven of these initiatives use ISO/IEC 15504 conformant process assessment methods.

Conclusion

During the last decade, in order to satisfy the on-going demand of mature software development companies for assessing and improving ITSM processes, different models which use the measurement framework of ISO/IEC 15504 have been developed. However, it is still necessary to define a method with the necessary guidelines to implement both software development processes and ITSM processes reducing the amount of effort, especially because some processes of both categories are overlapped.     

Assessment methodology for software process improvement in small organizations

ContextDiagnosing processes in a small company requires process assessment practices which give qualitative and quantitative results; these should offer an overall view of the process capability. The purpose is to obtain relevant information about the running of processes, for use in their control and improvement. However, small organizations have some problems in running process assessment, due to their specific characteristics and limitations.ObjectiveThis paper presents a methodology for assessing software processes which assist the activity of software process diagnosis in small organizations. There is an attempt to address issues such as the fact that: (i) process assessment is expensive and typically requires major company resources and (ii) many light assessment methods do not provide information that is detailed enough for diagnosing and improving processes.MethodTo achieve all this, the METvalCOMPETISOFT assessment methodology was developed. This methodology: (i) incorporates the strategy of internal assessments known as rapid assessment, meaning that these assessments do not take up too much time or use an excessive quantity of resources, nor are they too rigorous and (ii) meets all the requirements described in the literature for an assessment proposal which is customized to the typical features of small companies.ResultsThis paper also describes the experience of the application of this methodology in eight small software organizations that took part in the COMPETISOFT project. The results obtained show that this approach allows us to obtain reliable information about the strengths and weaknesses of software processes, along with information to companies on opportunities for improvement.ConclusionThe assessment methodology proposed sets out the elements needed to assist with diagnosing the process in small organizations step-by-step while seeking to make its application economically feasible in terms of resources and time. From the initial application it may be seen that this assessment methodology can be useful, practical and suitable for diagnosing processes in this type of organizations.     

Realism in assessment of effort estimation uncertainty: it matters how you ask

Traditionally, software professionals are requested to provide minimum-maximum intervals to indicate the uncertainty of their effort estimates. We claim that the traditional request is not optimal and leads to overoptimistic views about the level of estimation uncertainty. Instead, we propose that it is better to frame the request for uncertainty assessment: "How likely is it that the actual effort will be more than/less than X?" Our claim is based on the results of a previously reported-experiment and field studies in two companies. The two software companies were instructed to apply the traditional and our alternative framing on random samples of their projects. In total, we collected information about 47 projects applying the traditional-framing and 23 projects applying the alternative framing.     

Practical guidelines for expert-judgment-based software effort estimation

This article presents seven guidelines for producing realistic software development effort estimates. The guidelines derive from industrial experience and empirical studies. While many other guidelines exist for software effort estimation, these guidelines differ from them in three ways: 1) They base estimates on expert judgments rather than models. 2) They are easy to implement. 3) They use the most recent findings regarding judgment-based effort estimation. Estimating effort on the basis of expert judgment is the most common approach today, and the decision to use such processes instead of formal estimation models shouldn't be surprising. Simple process changes such as reframing questions can lead to more realistic estimates of software development efforts.     

The FreeBSD project: a replication case study of open source development

Case studies can help to validate claims that open source software development produces higher quality software at lower cost than traditional commercial development. One problem inherent in case studies are external validity - we do not know whether or not results from one case study apply to another development project. We gain or lose confidence in case study results when similar case studies are conducted on other projects. This case study of the FreeBSD project, a long-lived open source project, provides further understanding of open source development. The paper details a method for mining repositories and querying project participants to retrieve key process information. The FreeBSD development process is fairly well-defined with proscribed methods for determining developer responsibilities, dealing with enhancements and defects, and managing releases. Compared to the Apache project, FreeBSD uses 1) a smaller set of core developers - developers who control the code base - that implement a smaller percentage of the system, 2) a larger set of top developers to implement 80 percent of the system, and 3) a more well-defined testing process. FreeBSD and Apache have a similar ratio of core developers to people involved in adapting and debugging the system and people who report problems. Both systems have similar defect densities and the developers are also users in both systems.     

软件开发中的风险评估及其实践

在软件项目的开发过程中,准确地识别项目中存在的风险、对风险加以分析并采取有效的预防措施是保证项目成功的关键因素之一。风险评估是软件开发风险管理的重要组成部分,目前已经发展成为软件项目开发与控制的常用管理方法。文章叙述了Boehm关于风险评估的经典理论、SEI基于问卷调查的风险评估法、基于成本估算的风险评估法以及该领域的其它最新研究进展。最后对软件开发风险评估方法的发展方向提出了自己的观点。     

Sizing up today's lightweight software processes

There is a buzz about the new lightweight software development processes. These processes are certainly capable of creating successful software systems faster. As a software developer, which one should you choose for your project? Indeed, today's software development processes bring interesting dynamics to the projects to which developers apply them. But should process drive the project or should the project determine the process? I examine one characteristic of these processes, scalability, which can help you decide what process is best for you     

基于CMM的软件过程改进实践

CMM是一种软件生产过程标准和软件企业成熟度评估标准,该标准侧重于软件开发过程的管理及工程能力的提高与评估。基于CMM理论在软件过程改进中的应用,针对软件开发过程中存在的问题,采用CMM2级项目级实践,实现4个关键过程域：需求管理、软件项目计划、软件项目跟踪和监督、软件质量保证,制定出符合项目需求和管理的规范与过程,将CMM理论应用于软件开发过程中,对项目各个环节的工作进行改进,取得良好的过程改进效果,并从中总结基于CMM模型进行过程改进的经验。     

软件工程管理技术在中小软件开发企业的应用研究

研究了软件工程项目计划管理、项目进度管理、成本控制技术在中小软件开发企业中如何应用。重点研究可操作性和管理技术如何裁剪使管理成本降低,达到中小软件开发企业项目管理目标。     

水利信息化项目设计概（估）算编制研究

为规范水利信息化项目设计概(估)算编制,合理确定投资,针对水利信息化项目多学科、多行业交叉融合的特点,通过分析国内外相关标准规定,调研典型水利信息化项目实际情况,侧重解决概(估)算编制的重难点问题。提出符合水利信息化实际的项目划分、费用组成与单价构成,并结合软、硬件费用编制的特点,给出相关计算方法,最后通过实例应用验证相关结论。结果表明：水利信息化项目有别于常规水利工程以土木工程为主的特点,是以附加值含量高的软硬件设施设备为主体的新型基础设施项目,设计概(估)算编制应注重合理确定软硬件设备价格,根据项目实际情况科学划分并计算相关费用,才能满足项目设计概(估)算阶段投资控制的需要。     

Successfully implementing configuration management

To increase product quality, development efficiency, and enterprise profitability, many organizations are striving to achieve repeatable, engineered software development processes. Effective configuration management is essential to reaching this goal. CM can organize project components and streamline and control software development processes. A fully deployed and integrated CM solution consists of several tools. By carefully designing how CM components fit your processes and how your processes will change as a result of using CM, you can significantly enhance your software quality. We suggest an approach and provide planning and implementation guidelines for a pilot client-server software development project