Is software “green”? Application development environments and energy efficiency in open source applications

Context

The energy efficiency of IT systems, also referred to as Green IT, is attracting more and more attention. While several researchers have focused on the energy efficiency of hardware and embedded systems, the role of application software in IT energy consumption still needs investigation.

Objective

This paper aims to define a methodology for measuring software energy efficiency and to understand the consequences of abstraction layers and application development environments for the energy efficiency of software applications.

Method

We first develop a measure of energy efficiency that is appropriate for software applications. We then examine how the use of application development environments relates to this measure of energy efficiency for a sample of 63 open source software applications.

Results

Our findings indicate that a greater use of application development environments - specifically, frameworks and external libraries - is more detrimental in terms of energy efficiency for larger applications than for smaller applications. We also find that different functional application types have distinctly different levels of energy efficiency, with text and image editing and gaming applications being the most energy inefficient due to their intense use of the processor.

Conclusion

We conclude that different designs can have a significant impact on the energy efficiency of software applications. We have related the use of software application development environments to software energy efficiency suggesting that there may be a trade-off between development efficiency and energy efficiency. We propose new research to further investigate this topic.     

The agile requirements refinery: Applying SCRUM principles to software product management

Context

Although agile software development methods such as SCRUM and DSDM are gaining popularity, the consequences of applying agile principles to software product management have received little attention until now.

Objective

In this paper, this gap is filled by the introduction of a method for the application of SCRUM principles to software product management.

Method

A case study research approach is employed to describe and evaluate this method.

Results

This has resulted in the ‘agile requirements refinery’, an extension to the SCRUM process that enables product managers to cope with complex requirements in an agile development environment. A case study is presented to illustrate how agile methods can be applied to software product management.

Conclusions

The experiences of the case study company are provided as a set of lessons learned that will help others to apply agile principles to their software product management process.     

Software product line testing - A systematic mapping study

Context

Software product lines (SPL) are used in industry to achieve more efficient software development. However, the testing side of SPL is underdeveloped.

Objective

This study aims at surveying existing research on SPL testing in order to identify useful approaches and needs for future research.

Method

A systematic mapping study is launched to find as much literature as possible, and the 64 papers found are classified with respect to focus, research type and contribution type.

Results

A majority of the papers are of proposal research types (64%). System testing is the largest group with respect to research focus (40%), followed by management (23%). Method contributions are in majority.

Conclusions

More validation and evaluation research is needed to provide a better foundation for SPL testing.     

Pattern-based framework for modularized software development and evolution robustness

Context

Software development is now facing much more challenges than ever before due to the intrinsic high complexity and the increasing demands of the quick-service-ready paradigm.

Objective

As the developers are now called for more quality software systems from the industries, there is insufficient guidance from the methodologies and standards of software engineering that can provide assistance to the rapid development of qualified business software.

Method

In this work, we discuss the advantages of the pattern-based software development. We verify the benefits using a pattern-based software framework called OS2F, and a corresponding system design architecture that is intended for the rapid development of web applications.

Results

The objective of the framework/architecture is that, through software patterns, developers should be able to separate the work of system development from the business rules so as to reduce the problems caused by a developer’s lack of business experiences.

Conclusion

Through a suitable pattern-based software framework, the quality of the product can thus be enhanced, software development time and cost decreased, and software evolution robustness improved.     

Code churn estimation using organisational and code metrics: An experimental comparison

Context

Source code revision control systems contain vast amounts of data that can be exploited for various purposes. For example, the data can be used as a base for estimating future code maintenance effort in order to plan software maintenance activities. Previous work has extensively studied the use of metrics extracted from object-oriented source code to estimate future coding effort. In comparison, the use of other types of metrics for this purpose has received significantly less attention.

Objective

This paper applies machine learning techniques to unveil predictors of yearly cumulative code churn of software projects on the basis of metrics extracted from revision control systems.

Method

The study is based on a collection of object-oriented code metrics, XML code metrics, and organisational metrics. Several models are constructed with different subsets of these metrics. The predictive power of these models is analysed based on a dataset extracted from eight open-source projects.

Results

The study shows that a code churn estimation model built purely with organisational metrics is superior to one built purely with code metrics. However, a combined model provides the highest predictive power.

Conclusion

The results suggest that code metrics in general, and XML metrics in particular, are complementary to organisational metrics for the purpose of estimating code churn.     

Design guidelines for software processes knowledge repository development

Context

Staff turnover in organizations is an important issue that should be taken into account mainly for two reasons:

1.

Employees carry an organization’s knowledge in their heads and take it with them wherever they go

2.

Knowledge accessibility is limited to the amount of knowledge employees want to share

Objective

The aim of this work is to provide a set of guidelines to develop knowledge-based Process Asset Libraries (PAL) to store software engineering best practices, implemented as a wiki.

Method

Fieldwork was carried out in a 2-year training course in agile development. This was validated in two phases (with and without PAL), which were subdivided into two stages: Training and Project.

Results

The study demonstrates that, on the one hand, the learning process can be facilitated using PAL to transfer software process knowledge, and on the other hand, products were developed by junior software engineers with a greater degree of independence.

Conclusion

PAL, as a knowledge repository, helps software engineers to learn about development processes and improves the use of agile processes.     

An ant colony optimization algorithm to improve software quality prediction models: Case of class stability

Context

Assessing software quality at the early stages of the design and development process is very difficult since most of the software quality characteristics are not directly measurable. Nonetheless, they can be derived from other measurable attributes. For this purpose, software quality prediction models have been extensively used. However, building accurate prediction models is hard due to the lack of data in the domain of software engineering. As a result, the prediction models built on one data set show a significant deterioration of their accuracy when they are used to classify new, unseen data.

Objective

The objective of this paper is to present an approach that optimizes the accuracy of software quality predictive models when used to classify new data.

Method

This paper presents an adaptive approach that takes already built predictive models and adapts them (one at a time) to new data. We use an ant colony optimization algorithm in the adaptation process. The approach is validated on stability of classes in object-oriented software systems and can easily be used for any other software quality characteristic. It can also be easily extended to work with software quality predictive problems involving more than two classification labels.

Results

Results show that our approach out-performs the machine learning algorithm C4.5 as well as random guessing. It also preserves the expressiveness of the models which provide not only the classification label but also guidelines to attain it.

Conclusion

Our approach is an adaptive one that can be seen as taking predictive models that have already been built from common domain data and adapting them to context-specific data. This is suitable for the domain of software quality since the data is very scarce and hence predictive models built from one data set is hard to generalize and reuse on new data.     

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.     

Post-agility: What follows a decade of agility?

Context

Agile information systems development (ISD) has received much attention from both the practitioner and researcher community over the last 10-15 years. However, it is still unclear what precisely constitutes agile ISD.

Objective

Based on four empirical studies conducted over a 10-year time period from 1999 to 2008 the objective of this paper is to show how the meaning and practice of agile ISD has evolved over time and on this basis to speculate about what comes next.

Method

Four phases of research has been conducted, using a grounded theory approach. For each research phase qualitative interviews were held in American and/or Danish companies and a grounded theory was inductively discovered by careful data analysis. Subsequently, the four unique theories have been analyzed for common themes, and a global theory was identified across the empirical data.

Results

In 1999 companies were developing software at high-speed in a desperate rush to be first-to-market. In 2001 a new high-speed/quick results development process had become established practice. In 2003 changes in the market created the need for a more balanced view on speed and quality, and in 2008 companies were successfully combining agile and plan-driven approaches to achieve the benefits of both. The studies reveal a two-stage pattern in which dramatic changes in the market causes disruption of established practices and process adaptations followed by consolidation of lessons learnt into a once again stable software development process.

Conclusion

The cyclical history of punctuated process evolution makes it possible to distinguish pre-agility from current practices (agility), and on this basis, to speculate about post-agility: a possible next cycle of software process evolution concerned with proactively pursuing the dual goal of agility and alignment through a diversity of means.     

Development of a method for evaluating accessibility of medical equipment for patients with disabilities

Objective

The purpose of this study was to develop a method for evaluating accessibility of medical equipment for patients with disabilities.

Methods

The researchers reviewed videotapes of patient-participants with various physical and sensory disabilities using different types of medical equipment. For each of 11 videotapes, four observers independently identified and documented access and safety barriers, such as physical, sensory, cognitive, and environmental barriers. Inter-observer variability for identifying barrier presence was assessed with kappa statistics for pairs of observers.

Results

A list of 10 access and safety barriers was developed through an iterative consensus process, which identified design features of medical equipment that presented difficulties for participants with disabilities. The list is useful for identifying and categorizing accessibility problems found in equipment. While reliability of barrier identification was substantial or moderate for some barriers, reconciliation of barrier events identified by multiple video observers is recommended for optimal results.     

A systematic review of research on open source software in commercial software product development

Context

The popularity of the open source software development in the last decade, has brought about an increased interest from the industry on how to use open source components, participate in the open source community, build business models around this type of software development, and learn more about open source development methodologies. There is a need to understand the results of research in this area.

Objective

Since there is a need to understand conducted research, the aim of this study is to summarize the findings of research that has ben carried out on usage of open source components and development methodologies by the industry, as well as companies’ participation in the open source community.

Method

Systematic review through searches in library databases and manual identification of articles from the open source conference. The search was first carried out in May 2009 and then once again in May 2010.

Results

In 2009, 237 articles were first found, from which 19 were selected based on content and quality, and in 2010, 76 new articles were found from which four were selected. Twenty three articles were identified in total.

Conclusions

The articles could be divided into four categories: open source as part of component based software engineering, business models with open source in commercial organization, company participation in open source development communities, and usage of open source processes within a company.     

The value of software sizing

Context

One of the difficulties faced by software development Project Managers is estimating the cost and schedule for new projects. Previous industry surveys have concluded that software size and cost estimation is a significant technical area of concern. In order to estimate cost and schedule it is important to have a good understanding of the size of the software product to be developed. There are a number of techniques used to derive software size, with function points being amongst the most documented.

Objective

In this paper we explore the utility of function point software sizing techniques when applied to two levels of software requirements documentation in a commercial software development organisation. The goal of the research is to appraise the value (cost/benefit) which functional sizing techniques can bring to the project planning and management of software projects within a small-to-medium sized software development enterprise (SME).

Method

Functional counts were made at the bid and detailed functional specification stages for each of five commercial projects used in the research. Three variants of the NESMA method were used to determine these function counts. Through a structured interview session, feedback on the sizing results was obtained to evaluate its feasibility and potential future contribution to the company.

Results

The results of our research suggest there is value in performing size estimates at two appropriate stages in the software development lifecycle, with simplified methods providing the optimal return on effort expended.

Conclusion

The ‘Estimated NESMA’ is the most appropriate tool for use in size estimation for the company studied. The use of software sizing provides a valuable contribution which would augment, but not replace, the company’s existing cost estimation approach.     

Drivers of agile software development use: Dialectic interplay between benefits and hindrances

Context

Agile software development with its emphasis on producing working code through frequent releases, extensive client interactions and iterative development has emerged as an alternative to traditional plan-based software development methods. While a number of case studies have provided insights into the use and consequences of agile, few empirical studies have examined the factors that drive the adoption and use of agile.

Objective

We draw on intention-based theories and a dialectic perspective to identify factors driving the use of agile practices among adopters of this software development methodology.

Method

Data for the study was gathered through an anonymous online survey of software development professionals. We requested participation from members of a selected list of online discussion groups, and received 98 responses.

Results

Our analyses reveal that subjective norm and training play a significant role in influencing software developers’ use of agile processes and methods, while perceived benefits and perceived limitations are not primary drivers of agile use among adopters. Interestingly, perceived benefit emerges as a significant predictor of agile use only if adopters face hindrances to their agile practices.

Conclusion

We conclude that research in the adoption of software development innovations should examine the effects of both enabling and detracting factors and the interactions between them. Since training, subjective norm, and the interplay between perceived benefits and perceived hindrances appear to be key factors influencing the adoption of agile methods, researchers can focus on how to (a) perform training on agile methods more effectively, (b) facilitate the dialog between developers and managers about perceived benefits and hindrances, and (c) capitalize on subjective norm to publicize the benefits of agile methods within an organization. Further, when managing the transition to new software development methods, we recommend that practitioners adapt their strategies and tactics contingent on the extent of perceived hindrances to the change.     

Reliability analysis and optimal version-updating for open source software

Context

Although reliability is a major concern of most open source projects, research on this problem has attracted attention only recently. In addition, the optimal version-dating for open source software considering its special properties is not yet discussed.

Objective

In this paper, the reliability analysis and optimal version-updating for open source software are studied.

Method

A modified non-homogeneous Poisson process model is developed for open source software reliability modeling and analysis. Based on this model, optimal version-updating for open source software is investigated as well. In the decision process, the rapid release strategy and the level of reliability are the two most important factors. However, they are essentially contradicting with each other. In order to consider these two conflicting factors simultaneously, a new decision model based on multi-attribute utility theory is proposed.

Results

Our models are tested on the real world data sets from two famous open source projects: Apache and GNOME. It is found that traditional software reliability models provide overestimations of the reliability of open source software. In addition, the proposed decision model can help management to make a rational decision on the optimal version-updating for open source software.

Conclusion

Empirical results reveal that the proposed model for open source software reliability can describe the failure process more accurately. Furthermore, it can be seen that the proposed decision model can assist management to appropriately determine the optimal version-update time for open source software.     

Systematic literature review of machine learning based software development effort estimation models

Context

Software development effort estimation (SDEE) is the process of predicting the effort required to develop a software system. In order to improve estimation accuracy, many researchers have proposed machine learning (ML) based SDEE models (ML models) since 1990s. However, there has been no attempt to analyze the empirical evidence on ML models in a systematic way.

Objective

This research aims to systematically analyze ML models from four aspects: type of ML technique, estimation accuracy, model comparison, and estimation context.

Method

We performed a systematic literature review of empirical studies on ML model published in the last two decades (1991-2010).

Results

We have identified 84 primary studies relevant to the objective of this research. After investigating these studies, we found that eight types of ML techniques have been employed in SDEE models. Overall speaking, the estimation accuracy of these ML models is close to the acceptable level and is better than that of non-ML models. Furthermore, different ML models have different strengths and weaknesses and thus favor different estimation contexts.

Conclusion

ML models are promising in the field of SDEE. However, the application of ML models in industry is still limited, so that more effort and incentives are needed to facilitate the application of ML models. To this end, based on the findings of this review, we provide recommendations for researchers as well as guidelines for practitioners.     

Transfer learning for cross-company software defect prediction

Context

Software defect prediction studies usually built models using within-company data, but very few focused on the prediction models trained with cross-company data. It is difficult to employ these models which are built on the within-company data in practice, because of the lack of these local data repositories. Recently, transfer learning has attracted more and more attention for building classifier in target domain using the data from related source domain. It is very useful in cases when distributions of training and test instances differ, but is it appropriate for cross-company software defect prediction?

Objective

In this paper, we consider the cross-company defect prediction scenario where source and target data are drawn from different companies. In order to harness cross company data, we try to exploit the transfer learning method to build faster and highly effective prediction model.

Method

Unlike the prior works selecting training data which are similar from the test data, we proposed a novel algorithm called Transfer Naive Bayes (TNB), by using the information of all the proper features in training data. Our solution estimates the distribution of the test data, and transfers cross-company data information into the weights of the training data. On these weighted data, the defect prediction model is built.

Results

This article presents a theoretical analysis for the comparative methods, and shows the experiment results on the data sets from different organizations. It indicates that TNB is more accurate in terms of AUC (The area under the receiver operating characteristic curve), within less runtime than the state of the art methods.

Conclusion

It is concluded that when there are too few local training data to train good classifiers, the useful knowledge from different-distribution training data on feature level may help. We are optimistic that our transfer learning method can guide optimal resource allocation strategies, which may reduce software testing cost and increase effectiveness of software testing process.     

Modeling process-related RBAC models with extended UML activity models

Context

Business processes are an important source for the engineering of customized software systems and are constantly gaining attention in the area of software engineering as well as in the area of information and system security. While the need to integrate processes and role-based access control (RBAC) models has been repeatedly identified in research and practice, standard process modeling languages do not provide corresponding language elements.

Objective

In this paper, we are concerned with the definition of an integrated approach for modeling processes and process-related RBAC models - including roles, role hierarchies, statically and dynamically mutual exclusive tasks, as well as binding of duty constraints on tasks.

Method

We specify a formal metamodel for process-related RBAC models. Based on this formal model, we define a domain-specific extension for a standard modeling language.

Results

Our formal metamodel is generic and can be used to extend arbitrary process modeling languages. To demonstrate our approach, we present a corresponding extension for UML2 activity models. The name of our extension is Business Activities. Moreover, we implemented a library and runtime engine that can manage Business Activity runtime models and enforce the different policies and constraints in a software system.

Conclusion

The definition of process-related RBAC models at the modeling-level is an important prerequisite for the thorough implementation and enforcement of corresponding policies and constraints in a software system. We identified the need for modeling support of process-related RBAC models from our experience in real-world role engineering projects and case studies. The Business Activities approach presented in this paper is successfully applied in role engineering projects.     

Path dependent stochastic models to detect planned and actual technology use: A case study of OpenOffice

Context

Adopting IT innovation in organizations is a complex decision process driven by technical, social and economic issues. Thus, those organizations that decide to adopt innovation take a decision of uncertain success of implementation, as the actual use of a new technology might not be the one expected. The misalignment between planned and effective use of innovation is called assimilation gap.

Objective

This research aims at defining a quantitative instrument for measuring the assimilation gap and applying it to the case of the adoption of OSS.

Method

In this paper, we use the theory of path dependence and increasing returns of Arthur. In particular, we model the use of software applications (planned or actual) by stochastic processes defined by the daily amounts of files created with the applications. We quantify the assimilation gap by comparing the resulting models by measures of proximity.

Results

We apply and validate our method to a real case study of introduction of OpenOffice. We have found a gap between the planned and the effective use despite well-defined directives to use the new OS technology. These findings suggest a need of strategy re-calibration that takes into account environmental factors and individual attitudes.

Conclusions

The theory of path dependence is a valid instrument to model the assimilation gap provided information on strategy toward innovation and quantitative data on actual use are available.