Rules and Tools for Software Evolution Planning and Management

When first formulated in the early seventies, the laws of software evolution were, for a number of reasons, not widely accepted as relevant to software engineering practice. Over the years, however, they have gradually become recognised as providing useful inputs to understanding of the software process. Now eight in number, they have been supplemented by the software uncertainty principle and the FEAST (Feedback, Evolution And Software Technology) hypothesis. Based on all these and on the further results of the FEAST research projects this paper develops and presents some fifty rules for application in software system process planning and management and indicates tools available or that could usefully be developed to support their application. The listing is structured according to the laws that encapsulate the observed phenomena and that lead to the recommendations. Each sublist is preceded by a textual discussion providing at least some of the reasoning that has led to the recommended procedures. The references direct the interested reader to the literature that records observed behaviours, interpretations, models and metrics obtained from industrially evolved systems, and from which the recommendations were derived.     

基于反馈的软件演化过程模型

对软件演化及过程的特征进行了描述,提出软件演化过程的具体活动;分析了软件演化过程中的反馈机制,提出了基于扩展双变迁Petri网和反馈循环的软件演化过程模型.     

An Empirical Study of Lehman's Law on Software Quality Evolution

Software systems must change to adapt to new functional requirements and nonfunctional requirements. According to Lehman''s laws of software evolution, on the one side, the size and the complexity of a software system will continually increase in its life time; on the other side, the quality of a software system will decrease unless it is rigorously maintained and adapted. Lehman''s laws of software evolution, especially of those on software size and complexity, have been widely validated. However, there are few empirical studies of Lehman''s law on software quality evolution, despite the fact that quality is one of the most important measurements of a software product. This paper defines a metric---accumulated defect density---to measure the quality of evolving software systems. We mine the bug reports and measure the size and complexity growth of four evolution lines of Apache Tomcat and Apache Ant projects. Based on these studies, Lehman''s law on software quality evolution is examined and evaluated.     

软件演化过程的资源优化配置

在支持标准化的可配置、可重用且支持软件演化过程建模方法--第二代SDDM建模方法基础上,提出了软件演化过程性能分析与资源优化的方法,有效地支持了软件演化过程的改进.     

代码坏味对软件演化影响的实证研究

代码坏味是指程序设计中存在的不良设计模式或设计缺陷.坏味的存在,被认为会阻碍软件的演化与维护.近年来,研究人员致力于探究坏味产生的影响以及坏味与软件演化之间的关系.已有研究表明,代码坏味会随着软件的演化而不断发生变化.通常,软件的演化将涉及源文件的增加、修改与删除这3类具体操作,了解代码坏味与软件演化中源文件操作的关系,将有助于开发者更好地计划软件开发过程和重构软件代码.因此,针对13种常见的坏味,在8个Java项目共计104个版本中进行了系统的实证研究.研究发现,随着软件版本的演化,含代码坏味的文件在整个项目中的占比在不同的项目中呈现出不同的特征.另外,包含代码坏味的文件更倾向于被修改,而坏味本身与文件的添加或者删除并没有太大的关联.更进一步地,在探究的所有坏味中,有几种特定的坏味对文件的修改产生了显著的影响,且这些坏味文件间存在着明显的重叠.这些发现有助于开发人员更好地了解代码坏味,以便于更好地对软件进行维护.     

Software Evolution and the Code Fault Introduction Process

In any manufacturing environment, the fault introduction rate might be considered one of the most meaningful criterion to evaluate the goodness of the development process. In many investigations, the estimates of such a rate are often oversimplified or misunderstood generating unrealistic expectations on the prediction power of regression models with a fault criterion. The computation of fault introduction rates in software development requires accurate and consistent measurement, which translates into demanding parallel efforts for the development organization. This paper presents the techniques and mechanisms that can be implemented in a software development organization to provide a consistent method of anticipating fault content and structural evolution across multiple projects over time. The initial estimates of fault introduction rates can serve as a baseline against which future projects can be compared to determine whether progress is being made in reducing the fault introduction rate, and to identify those development techniques that seem to provide the greatest reduction.     

中小软件企业软件过程管理与改进策略

针对我国中小软件企业的软件过程现状,从改进对象、过程模型、开发个体、自评估、辅助工具等方面提出了几点策略,并提出了中小软件企业软件过程管理与评估系统的简要设计思路,旨在为我国中小软件企业的软件过程管理与改进工作提供建议。     

Requirements Engineering and Downstream Software Development: Findings from a Case Study

Requirements management is being recognized as one of the most important albeit difficult phases in software engineering. The literature repeatedly cites the role of well-defined requirements and requirements management process in problem analysis and project management as benefiting software development throughout the life cycle: during design, coding, testing, maintenance and documentation of software. This paper reports on the findings of an investigation into industrial practice of requirements management process improvement and its positive effects on downstream software development. The evidence reveals a strong relationship between a well-defined requirements process and increased developer productivity, improved project planning through better estimations and enhanced ability for stakeholders to negotiate project scope. These results are important since there is little empirical evidence of the actual benefits of sound requirements practice, in spite of the plethora of claims in the literature. An account of these effects not only adds to our understanding of good requirements practice but also provides strong motivation for software organizations to develop programs for improvement of their requirements processes.     

Software Evolution for Moving into and Moving within Internetware Paradigm

Internetware has been an emerging software paradigm to best support computing in the Internet era. Internetware emphasises accommodating the open, dynamic and uncontrollable natures of Internet, which directly and indirectly relates software evolvability. This paper observes that evolving non-Internetware software into the Internetware paradigm and evolving software within Internetware will be two main research and practical issues, and hence proposes an integrated approach to address these two issues. The proposed framework is based a three-dimension structure, with System Functions, System Quality and System models as dimensions. With this framework, evolving software into internetware paradigm can be viewed mainly as changing the qualities of existing software and evolving software within Internetware paradigm can be viewed mainly as changing software functions. The involved prototype tool, working examples and experiments conducted, are used to illustrate the proposed approach.     

A Dynamic Integrated Framework for Software Process Improvement

Current software process models (CMM, SPICE, etc.) strongly recommend the application of statistical control and measure guides to define, implement, and evaluate the effects of different process improvements. However, whilst quantitative modeling has been widely used in other fields, it has not been considered enough in the field of software process improvement. During the last decade software process simulation has been used to address a wide diversity of management problems. Some of these problems are related to strategic management, technology adoption, understanding, training and learning, and risk management, among others. In this work a dynamic integrated framework for software process improvement is presented. This framework combines traditional estimation models with an intensive utilization of dynamic simulation models of the software process. The aim of this framework is to support a qualitative and quantitative assessment for software process improvement and decision making to achieve a higher software development process capability according to the Capability Maturity Model. The concepts underlying this framework have been implemented in a software process improvement tool that has been used in a local software organization. The results obtained and the lessons learned are also presented in this paper.     

Empirical Measurement of the Effects of Cultural Diversity on Software Quality Management

The difficulties of achieving social acceptance for Software Quality Management systems have been underestimated in the past, and they will be exacerbated in the future by the globalization of the software market and the increasing use of cross-cultural development teams within multinational companies. Management that can take account of the cultural context of their endeavours will improve understanding, minimize risk and ensure a higher degree of success in improvement programs within the software industry.This paper addresses cross-cultural issues in Software Quality Management. Qualitative and quantitative research was carried out in five European countries by using a postal questionnaire. Empirical measures of organizational culture, national culture and their interdependence, are presented together with interim instruments developed for the purpose of classifying organizations. Verification of the statistical results from the survey was carried out by triangulation, which included qualitative research methods in the form of interviews and observation. Cultural factors, which may have bearing on successful adoption and implementation of Software Quality Management were identified, and an assessment model, has been developed for use by organizations developing software in different parts of the world. The intention is that the recommendations following from the assessment will lead to greater cultural awareness in addressing quality, and will provide stimulus for improvement. The model's aims is to predict to what degree there is a fit between the organizational and the national culture, and to give recommendations and guidelines for software process improvement.     

An empirical investigation of the relationship between spectra differences and regression faults

Many software maintenance and testing tasks involve comparing the behaviours of program versions. Program spectra have recently been proposed as a heuristic for use in performing such comparisons. To assess the potential usefulness of spectra in this context an experiment was conducted, examining the relationship between differences in program spectra and the exposure of regression faults (faults existing in a modified version of a program that were not present prior to modifications, or not revealed in previous testing), and empirically comparing several types of spectra. The results reveal that certain types of spectra differences correlate with high frequency—at least in one direction—with the exposure of regression faults. That is, when regression faults are revealed by particular inputs, spectra differences are likely also to be revealed by those inputs, though the reverse is not true. The results also suggest that several types of spectra that appear, analytically, to offer greater precision in predicting the presence of regression faults than other, cheaper, spectra may provide no greater precision in practice. These results have ramifications for future research on, and for the practical uses of, program spectra. Copyright © 2000 John Wiley & Sons, Ltd.     

An Incremental Approach to Software Process Assessment and Improvement

This paper considers assessment techniques based on the use of questionnaires, assessment matrices, workshops, and pro-forma assessment schemas; together with people issues such as motivation and involvement. With strong reference to SPICE process capability levels and the European Foundation for Quality Management (EFQM) Excellence Model, the authors suggest a novel framework containing a possible sequence of improvement steps towards the Established Level 3. The main conclusion in this paper is that an incremental improvement path can be defined using process assessment that commences with questionnaires, then goes on to matrices, workshops, and finally reaches pro-formas. Furthermore, it seems quite plausible that all four types of assessment techniques should be employed on an ongoing basis in a staged fashion.     

一种软件演化过程模型的代数语义

随着大量的软件演化过程模型被软件演化过程元模型建模产生,如何验证过程模型的正确性,是摆在人们面前的一个重要任务.针对软件演化过程元模型,引入进程代数ACP(algebra of communicating processes)对其扩展,提出软件演化过程元模型代数,使用进程项指定软件演化过程模型的代数语义,在进程代数的统一框架下,基于等式推理验证软件演化过程模型的行为,使行为验证方式从模型推导变为代数推导这种方法充分结合了Petri网和ACP的长处,可以有效地支持软件演化过程的形式验证.     

基于逻辑的软件演化操作语言及结构化操作语义

由于使用环境和新技术的不断变化,软件演化的控制变得日趋复杂.为了提高软件演化活动的可视化和形式化支持程度,结合谓词逻辑和软件演化,提出了一种软件演化操作语言SEOL(Software Evolution Operational Language)描述软件演化,给出了SEOL的语法和结构化操作语义描述,并指出了软件演化操作语义等价分析方法.结合软件代码演化和软件模型演化实例,说明了SEOL的应用.与已有的软件演化操作描述相比,SEOL在易用性、可重用性和形式化分析方面有明显的改善,为软件演化的管理、分析和实施奠定了基础.     

Modelling the Likelihood of Software Process Improvement: An Exploratory Study

Software process assessments have become big business worldwide. They can be a powerful tool for initiating and sustaining software process improvement (SPI). However, SPI programs sometimes fail. Moreover there still are very few systematic empirical investigations about the conditions under which SPI initiatives vary in their outcomes. In this paper we present the results of a study of factors that influence the success of SPI. The data come from a sample survey of organizations that have performed assessments based on the capability maturity model for software, and was conducted from 1 to 3 years after the assessments (sufficient time had passed for changes to have taken place). The results consist of a multivariate model of the conditions (e.g., how the improvement efforts are organized and funded) that can explain the successes and failures of SPI efforts. The model is constructed using a classification tree algorithm. It identifies the most important factors that affect the outcome of SPI efforts, and describes how those factors interact with each other to influence success or failure.     

一种软件特征模型扩展和演化分析方法

特征模型是面向特征的软件开发过程的重要概念和制品,该模型以特征为单位,刻画了领域产品的共性和可变性.在日趋频繁的软件演化过程中,保持特征模型的一致演化,对于支持高效的复用开发和按需配置至关重要.目前,大多数的研究是在需求层面进行共性和可变性分析,对特征模型的研究则集中在对共性和可变性的建模上.但是,由于特征变更在建模过程中存在"涟漪"效应,会导致新的共性和可变性演化.现有的分析方法还无法解决这个问题,会导致丢失一些潜在的产品共性,从而影响复用的效率.提出了一种特征模型扩展和演化分析方法.通过扩展特征关联关系和模型演化元操作,实现对特征变更"涟漪"效应的分析.发现潜在的产品共性,提出重构策略和半自动化的共性提取和特征重构支持方法.该方法还针对典型的配置冲突提出了冲突消解规则和策略.最后,通过案例分析验证了该方法的可用性和有效性.     

SPICE: Software Process Improvement and Capability Determination

In June 1991, the International Standards group for Software Engineering approved a study period to investigate the need and requirements for a standard for software process management. A new international work item has been subsequently raised. The resulting project is named SPICE (Software Process Improvement and Capability Determination). The project aims to build on the best features of existing software assessment methods.     

Product Focused Software Process Improvement: Concepts and Experiences from Industry

Management problems in the development of software have been addressed over the last years by a strong focus on the improvement of the development processes. Software process improvement (SPI) activities are characterized by an internal focus on a software development department and its procedures. However, the quality of the product is hardly addressed in software process improvement programs. This paper presents the application of a model for product focused SPI (P-SPI) and describes experiences with this model in practice. The main conclusions are that P-SPI puts products to be developed in a central position in improvement programs, results in fulfilling specific quality goals of a company and project, and industrial experiments show interesting benefits. Applying the approach in industrial projects showed that P-SPI is relatively cheap and gives fast results and high benefits.     

Knowledge Management in Medium-Sized Software Consulting Companies

This thesis investigates how Intranet-based knowledge management tools are used for various strategies in medium-sized software consultancy companies. It consists of three main parts: A survey of empirical work on knowledge management in software engineering, a multicase study of four medium-sized companies, and finally a thorough study on tool usage in two companies.