Analyzing evolution of variability in a software product line: From contexts and requirements to features

Context

In the long run, features of a software product line (SPL) evolve with respect to changes in stakeholder requirements and system contexts. Neither domain engineering nor requirements engineering handles such co-evolution of requirements and contexts explicitly, making it especially hard to reason about the impact of co-changes in complex scenarios.

Objective

In this paper, we propose a problem-oriented and value-based analysis method for variability evolution analysis. The method takes into account both kinds of changes (requirements and contexts) during the life of an evolving software product line.

Method

The proposed method extends the core requirements engineering ontology with the notions to represent variability-intensive problem decomposition and evolution. On the basis of problemorientation, the analysis method identifies candidate changes, detects influenced features, and evaluates their contributions to the value of the SPL.

Results and Conclusion

The process of applying the analysis method is illustrated using a concrete case study of an evolving enterprise software system, which has confirmed that tracing back to requirements and contextual changes is an effective way to understand the evolution of variability in the software product line.     

Individual empowerment of agile and non-agile software developers in small teams

ContextEmpowerment of employees at work has been known to have a positive impact on job motivation and satisfaction. Software development is a field of knowledge work wherein one should also expect to see these effects, and the idea of empowerment has become particularly visible in agile methodologies, in which proponents emphasise team empowerment and individual control of the work activities as a central concern.ObjectiveThis research aims to get a better understanding of how empowerment is enabled in software development teams, both agile and non-agile, to identify differences in empowering practices and levels of individual empowerment.MethodTwenty-five interviews with agile and non-agile developers from Norway and Canada on decision making and empowerment are analysed. The analysis is conducted using a conceptual model with categories for involvement, structural empowerment and psychological empowerment.ResultsBoth kinds of development organisations are highly empowered and they are similar in most aspects relating to empowerment. However, there is a distinction in the sense that agile developers have more possibilities to select work tasks and influence the priorities in a development project due to team empowerment. Agile developers seem to put a higher emphasis on the value of information in decision making, and have more prescribed activities to enable low-cost information flow. More power is obtained through the achievement of managing roles for the non-agile developers who show interest and are rich in initiatives.ConclusionAgile developers have a higher sense of being able to impact the organisation than non-agile developers and have information channels that is significantly differently from non-agile developers. For non-agile teams, higher empowerment can be obtained by systematically applying low-cost participative decision making practices in the manager–developer relation and among peer developers. For agile teams, it is essential to more rigorously follow the empowering practices already established.     

Managing requirements conflicts in software product lines: A goal and scenario based approach

The product line approach is recognized as a successful approach to reuse in software development. However, in many cases, it has resulted in interactions between requirements and/or features. Interaction detection, especially conflict detection between requirements has become more challenging. Thus, detecting conflicts between requirements is essential for successful product line development. Formal methods have been proposed to address this problem, however, they are hard to understand by non-experts and are limited to restricted domains. In addition, there is no overall process that covers all the steps for managing conflicts. We propose an approach for systematically identifying and managing requirements conflicts, which is based on requirements partition in natural language and supported by a tool. To demonstrate its feasibility, the proposed approach has been applied to the home integration system (HIS) domain and the results are discussed.     

An experiment on linguistic tool support for consolidation of requirements from multiple sources in market-driven product development

This paper presents an experiment with a linguistic support tool for consolidation of requirements sets. The experiment is designed based on the requirements management process at a large market-driven software development company that develops generic solutions to satisfy many different customers. New requirements and requests for information are continuously issued, which must be analyzed and responded to. The new requirements should first be consolidated with the old to avoid reanalysis of previously elicited requirements and to complement existing requirements with new information. In the presented experiment, a new open-source tool is evaluated in a laboratory setting. The tool uses linguistic engineering techniques to calculate similarities between requirements and presents a ranked list of suggested similar requirements, between which links may be assigned. It is hypothesized that the proposed technique for finding and linking similar requirements makes the consolidation more efficient. The results show that subjects that are given the support provided by the tool are significantly more efficient and more correct in consolidating two requirements sets, than are subjects that do not get the support. The results suggest that the proposed techniques may give valuable support and save time in an industrial requirements consolidation process.     

The impacts of user review on software responsiveness: Moderating requirements uncertainty

Rapidly changing business environments and evolving processes increase the uncertainties in IS development. To produce a high-quality system that responds to user needs is challenging. We attempted to determine whether user reviews during the development process could reduce uncertainties and improve the product. Technology structuration theory indicated that users, as actors participating in reviews during the development of a system, could help reduce uncertainty in the organizational requirements and thus improve the software product. A survey of system developers indicated that user requirements uncertainty had a direct, negative effect on software responsiveness but that user review, serving as a moderator, could reduce this effect.     

Integrating agile software development into stage-gate managed product development

Agile methods have evolved as a bottom-up approach to software development. However, as the software in embedded products is only one part of development projects, agile methods must coexist with project management models typically of the stage-gate type. This paper presents a qualitative case study of two large independent software system projects that have used eXtreme Programming (XP) for software development within contexts of stage-gate project management models. The study is comprised of open ended interviews with managers as well as practitioners, followed by a structured, fully traceable, qualitative analysis. We conclude that it is possible to integrate XP in a gate model context. Key issues for success are the interfaces towards the agile subproject and management attitudes towards the agile approach. Editor: Marvin Zelkowitz     

Managing requirements inter-dependency for software product line derivation

Software Product Line Engineering (SPLE) can reduce software development costs, reduce time to market and improve product quality. A software product line is a set of software products sharing a set of common features but containing variation points. Successful SPLE requires making selection decisions at variation points effectively and efficiently. A significant challenge is how to identify, represent and manage the inter-dependency of selection decisions for requirements. We developed the concept of a meta-model for requirement decision models to bring formalism and consistency to the structure and to model inter-dependencies between requirement selection decisions. Here we present a meta-model for requirement selection decisions that includes inter-dependencies and we use a mobile phone worked example to illustrate our approach. To support our method, we developed two separate tools, V-Define (for domain decision model construction) and V-Resolve (for new product derivation). Finally the results of a metal processing product line case study using the tools are described.

Agile methods rapidly replacing traditional methods at Nokia: A survey of opinions on agile transformation

Context

Many organizations have started to deploy agile methods, but so far there exist only a few studies on organization-wide transformations. Are agile methods here to stay? Some claim that agile software development methods are in the mainstream adoption phase in the software industry, while others hope that those are a passing fad. The assumption here is that if agile would not provide real improvement, adopters would be eager at first but turn pessimistic after putting it into practice.

Objective

Despite the growing amount of anecdotal evidence on the success of agile methods across a wide range of different real-life development settings, scientific studies remain scarce. Even less is known about the perception of the impacts of agile transformation when it is deployed in a very large software development environment, and whether agile methods are here to stay. This study aims to fill that gap by providing evidence from a large-scale agile transformation within Nokia. While we have yet to confirm these findings with solid quantitative data, we believe that the perception of the impacts already pinpoints the direction of the impacts of large-scale agile transformation.

Method

The data were collected using a questionnaire. The population of the study contains more than 1000 respondents in seven different countries in Europe, North America, and Asia.

Results

The results reveal that most respondents agree on all accounts with the generally claimed benefits of agile methods. These benefits include higher satisfaction, a feeling of effectiveness, increased quality and transparency, increased autonomy and happiness, and earlier detection of defects. Finally, 60% of respondents would not like to return to the old way of working.

Conclusion

While the perception of the impact of agile methods is predominantly positive, several challenge areas were discovered. However, based on this study, agile methods are here to stay.     

Advanced product planning: a comprehensive process for systemic definition of new product requirements

This paper reports results of research into the definition of requirements for new consumer products––specifically, electro-mechanical products. The research dealt with the derivation of design requirements that are demonstrably aligned with stakeholder needs. The paper describes a comprehensive process that can enable product development teams to deal with statements of product requirements, as originally collected through market research activities, in a systematic and traceable manner from the early, fuzzy front end, stages of the design process. The process described has been based on principles of systems engineering. A case study from its application and evaluation drawn from the power sector is described in this paper. The case study demonstrates how the process can significantly improve product quality planning practices through revision of captured product requirements, analysis of stakeholder requirements and derivation of design requirements. The paper discusses benefits and issues from the use of the process by product development teams, and identifies areas for further research. Finally, the conclusions drawn from the reported research are presented.

Decision support for moving from a single product to a product portfolio in evolving software systems

Successful software systems continuously evolve to accommodate ever-changing needs of customers. Accommodating the feature requests of all the customers in a single product increases the risks and costs of software maintenance. A possible approach to mitigate these risks is to transition the evolving software system (ESS) from a single system to a portfolio of related product variants, each addressing a specific customers’ segment. This evolution should be conducted such that the extent of modifications required in ESS's structure is reduced. The proposed method COPE+ uses preferences of customers on product features to generate multiple product portfolios each containing one product variant per segment of customers. Recommendations are given to the decision maker to update the product portfolios based on structural analysis of ESS. Product portfolios are compared with the ESS using statechart representations to identify the level of similarity in their behaviors. A proof of concept is presented by application to an open-source text editing system. Structural and behavioral analysis of candidate portfolios helped the decision maker to select one portfolio out of three candidates.     

The impact of agile practices on communication in software development

Agile software development practices such as eXtreme Programming (XP) and SCRUM have increasingly been adopted to respond to the challenges of volatile business environments, where the markets and technologies evolve rapidly and present the unexpected. In spite of the encouraging results so far, little is known about how agile practices affect communication. This article presents the results from a study which examined the impact of XP and SCRUM practices on communication within software development teams and within the focal organization. The research was carried out as a case study in F-Secure where two agile software development projects were compared from the communication perspective. The goal of the study is to increase the understanding of communication in the context of agile software development: internally among the developers and project leaders and in the interface between the development team and stakeholders (i.e. customers, testers, other development teams). The study shows that agile practices improve both informal and formal communication. However, it further indicates that, in larger development situations involving multiple external stakeholders, a mismatch of adequate communication mechanisms can sometimes even hinder the communication. The study highlights the fact that hurdles and improvements in the communication process can both affect the feature requirements and task subtask dependencies as described in coordination theory. While the use of SCRUM and some XP practices facilitate team and organizational communication of the dependencies between product features and working tasks, the use of agile practices requires that the team and organization use also additional plan-driven practices to ensure the efficiency of external communication between all the actors of software development.

The lean gap: A review of lean approaches to large-scale software systems development

Lean approaches to product development (LPD) have had a strong influence on many industries and in recent years there have been many proponents for lean in software development as it can support the increasing industry need of scaling agile software development. With it's roots in industrial manufacturing and, later, industrial product development, it would seem natural that LPD would adapt well to large-scale development projects of increasingly software-intensive products, such as in the automotive industry. However, it is not clear what kind of experience and results have been reported on the actual use of lean principles and practices in software development for such large-scale industrial contexts. This was the motivation for this study as the context was an ongoing industry process improvement project at Volvo Car Corporation and Volvo Truck Corporation.     

Using CMMI together with agile software development: A systematic review

BackgroundThe search for adherence to maturity levels by using lightweight processes that require low levels of effort is regarded as a challenge for software development organizations.ObjectiveThis study seeks to evaluate, synthesize, and present results on the use of the Capability Maturity Model Integration (CMMI) in combination with agile software development, and thereafter to give an overview of the topics researched, which includes a discussion of their benefits and limitations, the strength of the findings, and the implications for research and practice.MethodsThe method applied was a Systematic Literature Review on studies published up to (and including) 2011.ResultsThe search strategy identified 3193 results, of which 81 included studies on the use of CMMI together with agile methodologies. The benefits found were grouped into two main categories: those related to the organization in general and those related to the development process, and were organized into subcategories, according to the area to which they refer. The limitations were also grouped into these categories. Using the criteria defined, the strength of the evidence found was considered low. The implications of the results for research and practice are discussed.ConclusionAgile methodologies can be used by companies to reduce efforts in getting to levels 2 and 3 of CMMI, there even being reports of applying agile practices that led to achieving level 5. However, agile methodologies alone, according to the studies, were not sufficient to obtain a rating at a given level, it being necessary to resort to additional practices to do so.     

From integration to composition: On the impact of software product lines, global development and ecosystems

Three trends accelerate the increase in complexity of large-scale software development, i.e. software product lines, global development and software ecosystems. For the case study companies we studied, these trends caused several problems, which are organized around architecture, process and organization, and the problems are related to the efficiency and effectiveness of software development as these companies used too integration-centric approaches. We present five approaches to software development, organized from integration-centric to composition-oriented and describe the areas of applicability.     

A survey on the methods and tools of concurrent new product development and agile manufacturing

Companies in either manufacturing or servicing have to be restructured or re-organized in order to overcome with challenges of the 21st century in which customers are not only satisfied but also delighted. In this competitive environment, organizations should use a flexible, adaptive and responsive paradigm that can be entitled by a unique term: agile manufacturing (AM). An AM system is able to develop a variety of product at low cost and in a short time period. For this, it has some of useful enabling technologies and physical tools. Among these, concurrent engineering (CE) is a systematic approach to the integrated, concurrent design of product and their related processes, including manufacture and support. It is then a useful and beneficial approach to reduce the development time and manufacturing cost, while simultaneously improving the quality of a product in order to better respond to the customer expectations. The aim of this study is to underline the synergistic impact of new product development (NPD) and CE, (which can be called CNPD), and to survey their methods and tools in association with the AM.     

Using an ethnographic process to conduct requirements analysis for agile systems development

Since the late 1990s, agile or lightweight software development methodologies have experienced a meteoric rise of interest among systems developers who consider traditional systems development methodologies (such as Structured Systems Development, Information Engineering, and Rational Unified Process) too inflexible for building systems having unpredictable and changing requirements. Agile methodologies try to adapt to rapid requirement changes by having short, iterative development cycles and by encouraging frequent, open communication with customers. However, agile methodologies are still in the process of devising systematic approaches on how to be adaptive to unpredictable and changing requirements and how to incorporate customers into the systems development process. In this study, we show how an ethnographic research process called Strip Resolution can be applied as a systematic complement to projects applying agile development principles. We illustrate, in detail, how the Strip Resolution Process (SRP) enabled us, in the role of systems developers, to adapt to changing and unpredictable user requirements and to incorporate customers into the systems development process.     

基于敏捷软件开发方法的基金管理信息系统开发

敏捷软件开发是一种面临迅速变化的需求快速开发出高质量的软件产品软件的新方法。介绍了敏捷软件开发的主要内容,特别是XP和AM,并以一个基金管理信息系统的开发为例,展示了实际应用过程。     

A systematic review of evaluation of variability management approaches in software product lines

Context

Variability management (VM) is one of the most important activities of software product-line engineering (SPLE), which intends to develop software-intensive systems using platforms and mass customization. VM encompasses the activities of eliciting and representing variability in software artefacts, establishing and managing dependencies among different variabilities, and supporting the exploitation of the variabilities for building and evolving a family of software systems. Software product line (SPL) community has allocated huge amount of effort to develop various approaches to dealing with variability related challenges during the last two decade. Several dozens of VM approaches have been reported. However, there has been no systematic effort to study how the reported VM approaches have been evaluated.

Objective

The objectives of this research are to review the status of evaluation of reported VM approaches and to synthesize the available evidence about the effects of the reported approaches.

Method

We carried out a systematic literature review of the VM approaches in SPLE reported from 1990s until December 2007.

Results

We selected 97 papers according to our inclusion and exclusion criteria. The selected papers appeared in 56 publication venues. We found that only a small number of the reviewed approaches had been evaluated using rigorous scientific methods. A detailed investigation of the reviewed studies employing empirical research methods revealed significant quality deficiencies in various aspects of the used quality assessment criteria. The synthesis of the available evidence showed that all studies, except one, reported only positive effects.

Conclusion

The findings from this systematic review show that a large majority of the reported VM approaches have not been sufficiently evaluated using scientifically rigorous methods. The available evidence is sparse and the quality of the presented evidence is quite low. The findings highlight the areas in need of improvement, i.e., rigorous evaluation of VM approaches. However, the reported evidence is quite consistent across different studies. That means the proposed approaches may be very beneficial when they are applied properly in appropriate situations. Hence, it can be concluded that further investigations need to pay more attention to the contexts under which different approaches can be more beneficial.     

A model-driven approach for the derivation of architectural requirements of software product lines

The alignment of the software architecture and the functional requirements of a system is a demanding task because of the difficulty in tracing design elements to requirements. The four-step rule set (4SRS) is a unified modeling language (UML)-based model-driven method for single system development which provides support to the software architect in this task. This paper presents an evolution of the 4SRS method aimed at software product lines. In particular, we describe how to address the transformation of functional requirements (use cases) into component-based requirements for the product line architecture. The result is a UML-based model-driven method that can be applied in combination with metamodeling tools such as the eclipse modeling framework (EMF) to derive the architecture of software product lines. We present our approach in a practical way and illustrate it with an example. We also discuss how our proposals are related to the work of other authors.