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  • 1. Afzal, Wasif
    et al.
    Ghazi, Ahmad Nauman
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Itkonen, Juha
    Torkar, Richard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Andrews, Anneliese
    Bhatti, Khurram
    An experiment on the effectiveness and efficiency of exploratory testing2015Ingår i: Empirical Software Engineering, ISSN 1382-3256, Vol. 20, nr 3, s. 844-878Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The exploratory testing (ET) approach is commonly applied in industry, but lacks scientific research. The scientific community needs quantitative results on the performance of ET taken from realistic experimental settings. The objective of this paper is to quantify the effectiveness and efficiency of ET vs. testing with documented test cases (test case based testing, TCT). We performed four controlled experiments where a total of 24 practitioners and 46 students performed manual functional testing using ET and TCT. We measured the number of identified defects in the 90-minute testing sessions, the detection difficulty, severity and types of the detected defects, and the number of false defect reports. The results show that ET found a significantly greater number of defects. ET also found significantly more defects of varying levels of difficulty, types and severity levels. However, the two testing approaches did not differ significantly in terms of the number of false defect reports submitted. We conclude that ET was more efficient than TCT in our experiment. ET was also more effective than TCT when detection difficulty, type of defects and severity levels are considered. The two approaches are comparable when it comes to the number of false defect reports submitted.

  • 2. Afzal, Wasif
    et al.
    Torkar, Richard
    A Comparative Evaluation of Using Genetic Programming for Predicting Fault Count Data2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    There have been a number of software reliability growth models (SRGMs) proposed in literature. Due to several reasons, such as violation of models' assumptions and complexity of models, the practitioners face difficulties in knowing which models to apply in practice. This paper presents a comparative evaluation of traditional models and use of genetic programming (GP) for modeling software reliability growth based on weekly fault count data of three different industrial projects. The motivation of using a GP approach is its ability to evolve a model based entirely on prior data without the need of making underlying assumptions. The results show the strengths of using GP for predicting fault count data.

  • 3.
    Afzal, Wasif
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för programvarusystem.
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för programvarusystem.
    Incorporating Metrics in an Organizational Test Strategy2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    An organizational level test strategy needs to incorporate metrics to make the testing activities visible and available to process improvements. The majority of testing measurements that are done are based on faults found in the test execution phase. In contrast, this paper investigates metrics to support software test planning and test design processes. We have assembled metrics in these two process types to support management in carrying out evidence-based test process improvements and to incorporate suitable metrics as part of an organization level test strategy. The study is composed of two steps. The first step creates a relevant context by analyzing key phases in the software testing lifecycle, while the second step identifies the attributes of software test planning and test design processes along with metric(s) support for each of the identified attributes.

  • 4. Afzal, Wasif
    et al.
    Torkar, Richard
    On the application of genetic programming for software engineering predictive modeling: A systematic review2011Ingår i: Expert Systems with Applications, ISSN 0957-4174 , Vol. 38, nr 9, s. 11984-11997Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The objective of this paper is to investigate the evidence for symbolic regression using genetic programming (GP) being an effective method for prediction and estimation in software engineering, when compared with regression/machine learning models and other comparison groups (including comparisons with different improvements over the standard GP algorithm). We performed a systematic review of literature that compared genetic programming models with comparative techniques based on different independent project variables. A total of 23 primary studies were obtained after searching different information sources in the time span 1995-2008. The results of the review show that symbolic regression using genetic programming has been applied in three domains within software engineering predictive modeling: (i) Software quality classification (eight primary studies). (ii) Software cost/effort/size estimation (seven primary studies). (iii) Software fault prediction/software reliability growth modeling (eight primary studies). While there is evidence in support of using genetic programming for software quality classification, software fault prediction and software reliability growth modeling: the results are inconclusive for software cost/effort/size estimation.

  • 5. Afzal, Wasif
    et al.
    Torkar, Richard
    Suitability of Genetic Programming for Software Reliability Growth Modeling2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Genetic programming (GP) has been found to be effective in finding a model that fits the given data points without making any assumptions about the model structure. This makes GP a reasonable choice for software reliability growth modeling. This paper discusses the suitability of using GP for software reliability growth modeling and highlights the mechanisms that enable GP to progressively search for fitter solutions.

  • 6. Afzal, Wasif
    et al.
    Torkar, Richard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Towards benchmarking feature subset selection methods for software fault prediction2016Ingår i: Studies in Computational Intelligence, Springer, 2016, 617, Vol. 617, s. 33-58Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Despite the general acceptance that software engineering datasets often contain noisy, irrelevant or redundant variables, very few benchmark studies of feature subset selection (FSS) methods on real-life data from software projects have been conducted. This paper provides an empirical comparison of state-of-the-art FSS methods: information gain attribute ranking (IG); Relief (RLF); principal component analysis (PCA); correlation-based feature selection (CFS); consistencybased subset evaluation (CNS); wrapper subset evaluation (WRP); and an evolutionary computation method, genetic programming (GP), on five fault prediction datasets from the PROMISE data repository. For all the datasets, the area under the receiver operating characteristic curve—the AUC value averaged over 10-fold cross-validation runs—was calculated for each FSS method-dataset combination before and after FSS. Two diverse learning algorithms, C4.5 and naïve Bayes (NB) are used to test the attribute sets given by each FSS method. The results show that although there are no statistically significant differences between the AUC values for the different FSS methods for both C4.5 and NB, a smaller set of FSS methods (IG, RLF, GP) consistently select fewer attributes without degrading classification accuracy. We conclude that in general, FSS is beneficial as it helps improve classification accuracy of NB and C4.5. There is no single best FSS method for all datasets but IG, RLF and GP consistently select fewer attributes without degrading classification accuracy within statistically significant boundaries. © Springer International Publishing Switzerland 2016.

  • 7. Afzal, Wasif
    et al.
    Torkar, Richard
    Feldt, Robert
    A Systematic Mapping Study on Non-Functional Search-Based Software Testing2008Konferensbidrag (Refereegranskat)
  • 8. Afzal, Wasif
    et al.
    Torkar, Richard
    Feldt, Robert
    A systematic review of search-based testing for non-functional system properties2009Ingår i: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 51, nr 6, s. 957-976Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Search-based software testing is the application of metaheuristic search techniques to generate software tests. The test adequacy criterion is transformed into a fitness function and a set of solutions in the search space are evaluated with respect to the fitness function using a metaheuristic search technique. The application of metaheuristic search techniques for testing is promising due to the fact that exhaustive testing is infeasible considering the size and complexity of software under test. Search-based software testing has been applied across the spectrum of test case design methods; this includes white-box (structural), black-box (functional) and grey-box (combination of structural and functional) testing. In addition, metaheuristic search techniques have also been applied to test non-functional properties. The overall objective of undertaking this systematic review is to examine existing work into non-functional search-based software testing (NFSBST). We are interested in types of non-functional testing targeted using metaheuristic search techniques, different fitness functions used in different types of search-based non-functional testing and challenges in the application of these techniques. The systematic review is based on a comprehensive set of 35 articles obtained after a multi-stage selection process and have been published in the time span 1996-2007. The results of the review show that metaheuristic search techniques have been applied for non-functional testing of execution time, quality of service, security, usability and safety. A variety of metaheuristic search techniques are found to be applicable for non-functional testing including simulated annealing, tabu search, genetic algorithms, ant colony methods, grammatical evolution, genetic programming (and its variants including linear genetic programming) and swarm intelligence methods. The review reports on different fitness functions used to guide the search for each of the categories of execution time, safety, usability, quality of service and security; along with a discussion of possible challenges in the application of metaheuristic search techniques.

  • 9. Afzal, Wasif
    et al.
    Torkar, Richard
    Feldt, Robert
    Prediction of fault count data using genetic programming2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Software reliability growth modeling helps in deciding project release time and managing project resources. A large number of such models have been presented in the past. Due to the existence of many models, the models' inherent complexity, and their accompanying assumptions; the selection of suitable models becomes a challenging task. This paper presents empirical results of using genetic programming (GP) for modeling software reliability growth based on weekly fault count data of three different industrial projects. The goodness of fit (adaptability) and predictive accuracy of the evolved model is measured using five different measures in an attempt to present a fair evaluation. The results show that the GP evolved model has statistically significant goodness of fit and predictive accuracy.

  • 10.
    Afzal, Wasif
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Feldt, Robert
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Resampling Methods in Software Quality Classification2012Ingår i: International Journal of Software Engineering and Knowledge Engineering, ISSN 0218-1940, Vol. 22, nr 2, s. 203-223Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the presence of a number of algorithms for classification and prediction in software engineering, there is a need to have a systematic way of assessing their performances. The performance assessment is typically done by some form of partitioning or resampling of the original data to alleviate biased estimation. For predictive and classification studies in software engineering, there is a lack of a definitive advice on the most appropriate resampling method to use. This is seen as one of the contributing factors for not being able to draw general conclusions on what modeling technique or set of predictor variables are the most appropriate. Furthermore, the use of a variety of resampling methods make it impossible to perform any formal meta-analysis of the primary study results. Therefore, it is desirable to examine the influence of various resampling methods and to quantify possible differences. Objective and method: This study empirically compares five common resampling methods (hold-out validation, repeated random sub-sampling, 10-fold cross-validation, leave-one-out cross-validation and non-parametric bootstrapping) using 8 publicly available data sets with genetic programming (GP) and multiple linear regression (MLR) as software quality classification approaches. Location of (PF, PD) pairs in the ROC (receiver operating characteristics) space and area under an ROC curve (AUC) are used as accuracy indicators. Results: The results show that in terms of the location of (PF, PD) pairs in the ROC space, bootstrapping results are in the preferred region for 3 of the 8 data sets for GP and for 4 of the 8 data sets for MLR. Based on the AUC measure, there are no significant differences between the different resampling methods using GP and MLR. Conclusion: There can be certain data set properties responsible for insignificant differences between the resampling methods based on AUC. These include imbalanced data sets, insignificant predictor variables and high-dimensional data sets. With the current selection of data sets and classification techniques, bootstrapping is a preferred method based on the location of (PF, PD) pair data in the ROC space. Hold-out validation is not a good choice for comparatively smaller data sets, where leave-one-out cross-validation (LOOCV) performs better. For comparatively larger data sets, 10-fold cross-validation performs better than LOOCV.

  • 11. Afzal, Wasif
    et al.
    Torkar, Richard
    Feldt, Robert
    Search-based prediction of fault count data2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    Symbolic regression, an application domain of genetic programming (GP), aims to find a function whose output has some desired property, like matching target values of a particular data set. While typical regression involves finding the coefficients of a pre-defined function, symbolic regression finds a general function, with coefficients, fitting the given set of data points. The concepts of symbolic regression using genetic programming can be used to evolve a model for fault count predictions. Such a model has the advantages that the evolution is not dependent on a particular structure of the model and is also independent of any assumptions, which are common in traditional time-domain parametric software reliability growth models. This research aims at applying experiments targeting fault predictions using genetic programming and comparing the results with traditional approaches to compare efficiency gains.

  • 12. Afzal, Wasif
    et al.
    Torkar, Richard
    Feldt, Robert
    Gorschek, Tony
    Genetic programming for cross-release fault count predictions in large and complex software projects2010Ingår i: Evolutionary Computation and Optimization Algorithms in Software Engineering: Applications and Techniques / [ed] Chis, Monica, Hershey: IGI Global, Hershey, USA , 2010Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Software fault prediction can play an important role in ensuring software quality through efficient resource allocation. This could, in turn, reduce the potentially high consequential costs due to faults. Predicting faults might be even more important with the emergence of short-timed and multiple software releases aimed at quick delivery of functionality. Previous research in software fault prediction has indicated that there is a need i) to improve the validity of results by having comparisons among number of data sets from a variety of software, ii) to use appropriate model evaluation measures and iii) to use statistical testing procedures. Moreover, cross-release prediction of faults has not yet achieved sufficient attention in the literature. In an attempt to address these concerns, this paper compares the quantitative and qualitative attributes of 7 traditional and machine-learning techniques for modeling the cross-release prediction of fault count data. The comparison is done using extensive data sets gathered from a total of 7 multi-release open-source and industrial software projects. These software projects together have several years of development and are from diverse application areas, ranging from a web browser to a robotic controller software. Our quantitative analysis suggests that genetic programming (GP) tends to have better consistency in terms of goodness of fit and accuracy across majority of data sets. It also has comparatively less model bias. Qualitatively, ease of configuration and complexity are less strong points for GP even though it shows generality and gives transparent models. Artificial neural networks did not perform as well as expected while linear regression gave average predictions in terms of goodness of fit and accuracy. Support vector machine regression and traditional software reliability growth models performed below average on most of the quantitative evaluation criteria while remained on average for most of the qualitative measures.

  • 13. Afzal, Wasif
    et al.
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Feldt, Robert
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Gorschek, Tony
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Prediction of faults-slip-through in large software projects: an empirical evaluation2014Ingår i: Software quality journal, ISSN 0963-9314, E-ISSN 1573-1367, Vol. 22, nr 1, s. 51-86Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A large percentage of the cost of rework can be avoided by finding more faults earlier in a software test process. Therefore, determination of which software test phases to focus improvement work on has considerable industrial interest. We evaluate a number of prediction techniques for predicting the number of faults slipping through to unit, function, integration, and system test phases of a large industrial project. The objective is to quantify improvement potential in different test phases by striving toward finding the faults in the right phase. The results show that a range of techniques are found to be useful in predicting the number of faults slipping through to the four test phases; however, the group of search-based techniques (genetic programming, gene expression programming, artificial immune recognition system, and particle swarm optimization-based artificial neural network) consistently give better predictions, having a representation at all of the test phases. Human predictions are consistently better at two of the four test phases. We conclude that the human predictions regarding the number of faults slipping through to various test phases can be well supported by the use of search-based techniques. A combination of human and an automated search mechanism (such as any of the search-based techniques) has the potential to provide improved prediction results.

  • 14. Afzal, Wasif
    et al.
    Torkar, Richard
    Feldt, Robert
    Wikstrand, Greger
    Search-based prediction of fault-slip-through in large software projects2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    A large percentage of the cost of rework can be avoided by finding more faults earlier in a software testing process. Therefore, determination of which software testing phases to focus improvements work on, has considerable industrial interest. This paper evaluates the use of five different techniques, namely particle swarm optimization based artificial neural networks (PSO-ANN), artificial immune recognition systems (AIRS), gene expression programming (GEP), genetic programming (GP) and multiple regression (MR), for predicting the number of faults slipping through unit, function, integration and system testing phases. The objective is to quantify improvement potential in different testing phases by striving towards finding the right faults in the right phase. We have conducted an empirical study of two large projects from a telecommunication company developing mobile platforms and wireless semiconductors. The results are compared using simple residuals, goodness of fit and absolute relative error measures. They indicate that the four search-based techniques (PSO-ANN, AIRS, GEP, GP) perform better than multiple regression for predicting the fault-slip-through for each of the four testing phases. At the unit and function testing phases, AIRS and PSO-ANN performed better while GP performed better at integration and system testing phases. The study concludes that a variety of search-based techniques are applicable for predicting the improvement potential in different testing phases with GP showing more consistent performance across two of the four test phases.

  • 15. Bäumer, Martin
    et al.
    Siedler, Patrick
    Torkar, Richard
    Tomaszewski, Piotr
    Damm, Lars-Ola
    Feldt, Robert
    Predicting Fault Inflow in Iterative Software Development Processes: An Industrial Evaluation2008Konferensbidrag (Refereegranskat)
  • 16. Edison, Henry
    et al.
    bin Ali, Nauman
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Towards innovation measurement in the software industry2013Ingår i: Journal of Systems and Software, ISSN 0164-1212, Vol. 86, nr 5, s. 1390-1407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In today's highly competitive business environments with shortened product and technology life cycle, it is critical for software industry to continuously innovate. This goal can be achieved by developing a better understanding and control of the activities and determinants of innovation. Innovation measurement initiatives assess innovation capability, output and performance to help develop such an understanding. This study explores various aspects relevant to innovation measurement ranging from definitions, measurement frameworks and metrics that have been proposed in literature and used in practice. A systematic literature review followed by an online questionnaire and interviews with practitioners and academics were employed to identify a comprehensive definition of innovation that can be used in software industry. The metrics for the evaluation of determinants, inputs, outputs and performance were also aggregated and categorised. Based on these findings, a conceptual model of the key measurable elements of innovation was constructed from the findings of the systematic review. The model was further refined after feedback from academia and industry through interviews.

  • 17. Feldt, Robert
    et al.
    Angelis, Lefteris
    Torkar, Richard
    Samuelsson, Maria
    Links between the personalities, views and attitudes of software engineers2010Ingår i: Information and Software Technology, ISSN 0950-5849 , Vol. 52, nr 6, s. 611-624Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Successful software development and management depends not only on the technologies, methods and processes employed but also on the judgments and decisions of the humans involved. These, in turn, are affected by the basic views and attitudes of the individual engineers. The objective of this paper is to establish if these views and attitudes can be linked to the personalities of software engineers. We summarize the literature on personality and software engineering and then describe an empirical study on 47 professional engineers in ten different Swedish software development companies. The study evaluated the personalities of these engineers via the IPIP 50-item five-factor personality test and prompted them on their attitudes towards and basic views on their professional activities. We present extensive statistical analyses of their responses to show that there are multiple, significant associations between personality factors and software engineering attitudes. The tested individuals are more homogeneous in personality than a larger sample of individuals from the general population. Taken together, the methodology and personality test we propose and the associated statistical analyses can help find and quantify relations between complex factors in software engineering projects in both research and practice.

  • 18. Feldt, Robert
    et al.
    Marculescu, Bogdan
    Schulte, Jan
    Torkar, Richard
    Preissing, Philip
    Hult, Erika
    Optimizing Verification and Validation Activities for Software in the Space Industry2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Software for space applications has special requirements in terms of reliability and dependability and the verification & validation activities (VAs) of these systems often account for more than 50% of the develop- ment effort. The industry is also faced with political and market pressure to deliver software faster and cheaper. Thus new ways are needed to optimize these activities so that high quality can be retained even with reduced costs and effort. Here we present a framework for the management and optimization of verification & validation activities (VAMOS). An initial evaluation of the framework based on historical data as well as data extracted with a new tool has been done and are described briefly.

  • 19. Feldt, Robert
    et al.
    Torkar, Richard
    Ahmad, Ehsan
    Raza, Bilal
    Challenges with Software Verification and Validation Activities in the Space Industry2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Developing software for high-dependable space applications and systems is a formidable task. With new political and market pressures on the space industry to deliver more software at a lower cost, optimization of their methods and standards need to be investigated. The industry has to follow standards that strictly set quality goals and prescribes engineering processes and methods to fulfill them. The overall goal of this study is to evaluate if current use of the standards from the European Cooperation for Space Standardization (ECSS) is cost efficient and if there are ways to make the process leaner while still maintaining quality and to analyze if their verification and validation (V&V) activities can be optimized. This paper presents results from two industrial case studies of companies in the European space industry that are following ECSS standards in various V&V activities. The case studies reported here focus on how ECSS standards are used by the companies, how that affects their processes and, in the end, how their V&V activities can be further optimized.

  • 20. Feldt, Robert
    et al.
    Torkar, Richard
    Angelis, Lefteris
    Samuelsson, Maria
    Towards Individualized Software Engineering: Empirical Studies Should Collect Psyhometrics2008Konferensbidrag (Refereegranskat)
  • 21. Feldt, Robert
    et al.
    Torkar, Richard
    Gorschek, Tony
    Afzal, Wasif
    Searching for Cognitively Diverse Tests: Towards Universal Test Diversity Metrics2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Search-based software testing (SBST) has shown a potential to decrease cost and increase quality of testingrelated software development activities. Research in SBST has so far mainly focused on the search for isolated tests that are optimal according to a fitness function that guides the search. In this paper we make the case for fitness functions that measure test fitness in relation to existing or previously found tests; a test is good if it is diverse from other tests. We present a model for test variability and propose the use of a theoretically optimal diversity metric at variation points in the model. We then describe how to apply a practically useful approximation to the theoretically optimal metric. The metric is simple and powerful and can be adapted to a multitude of different test diversity measurement scenarios. We present initial results from an experiment to compare how similar to human subjects, the metric can cluster a set of test cases. To carry out the experiment we have extended an existing framework for test automation in an object-oriented, dynamic programming language.

  • 22.
    Gorschek, Tony
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Gomes, Andrigo
    Pettersson, Andreas
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Introduction of a Process Maturity Model for Market-driven Product Management and Requirements engineering2012Ingår i: Journal of Software Maintenance and Evolution: Research and Practice, ISSN 1532-060X, E-ISSN 1532-0618, Vol. 24, nr 1, s. 83-113Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The area of software product development of software intensive products has received much attention, especially in the area of requirements engineering and product management. Many companies are faced with new challenges when operating in an environment where potential requirements number in thousands or even tens of thousands, and where a product does not have a customer, but any number of customers or markets. The development organization carries not only all the costs of development, but also takes all the risks. In this environment traditional bespoke requirements engineering, together with traditional process assessment and improvement models fall short as they do not address the unique challenges of a market-driven environment. This paper introduces the Market-driven Requirements Engineering Process Model, aimed at enabling process improvement and process assurance for organizations faced with these new challenges. The model is also validated in the industry through three case studies where the model is used for process assessment and improvement suggestion. Initial results show that the model is appropriate for process improvement for organizations operating in a market-driven environment. In addition, the model was designed to be light weight in terms of low cost and thus adapted not only for large organizations but suitable for small and medium enterprises as well.

  • 23.
    Gren, Lucas
    et al.
    Chalmers, SWE.
    Torkar, Richard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Feldt, Robert
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Group development and group maturity when building agile teams: A qualitative and quantitative investigation at eight large companies2017Ingår i: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 124, s. 104-119Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The agile approach to projects focuses more on close-knit teams than traditional waterfall projects, which means that aspects of group maturity become even more important. This psychological aspect is not much researched in connection to the building of an “agile team.” The purpose of this study is to investigate how building agile teams is connected to a group development model taken from social psychology. We conducted ten semi-structured interviews with coaches, Scrum Masters, and managers responsible for the agile process from seven different companies, and collected survey data from 66 group-members from four companies (a total of eight different companies). The survey included an agile measurement tool and the one part of the Group Development Questionnaire. The results show that the practitioners define group developmental aspects as key factors to a successful agile transition. Also, the quantitative measurement of agility was significantly correlated to the group maturity measurement. We conclude that adding these psychological aspects to the description of the “agile team” could increase the understanding of agility and partly help define an “agile team.” We propose that future work should develop specific guidelines for how software development teams at different maturity levels might adopt agile principles and practices differently.

  • 24. Gren, Lucas
    et al.
    Torkar, Richard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Feldt, Robert
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Group Maturity and Agility, Are They Connected?: – A Survey Study2015Ingår i: Proceedings of the 41st EUROMICRO Conference on Software Engineering and Advanced Applications (SEAA), IEEE, 2015, s. 1-8Konferensbidrag (Refereegranskat)
    Abstract [en]

    The focus on psychology has increased within software engineering due to the project management innovation "agile development processes". The agile methods do not explicitly consider group development aspects; they simply assume what is described in group psychology as mature groups. This study was conducted with 45 employees and their twelve managers (N=57) from two SAP customers in the US that were working with agile methods, and the data were collected via an online survey. The selected Agility measurement was correlated to a Group Development measurement and showed significant convergent validity, i.e., a more mature team is also a more agile team. This means that the agile methods probably would benefit from taking group development into account when its practices are being introduced.

  • 25. Gren, Lucas
    et al.
    Torkar, Richard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Feldt, Robert
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Work motivational challenges regarding the interface between agile teams and a non-agile surrounding organization: A case study2014Ingår i: 2014 AGILE CONFERENCE (AGILE), IEEE Press, 2014, s. 11-15Konferensbidrag (Refereegranskat)
  • 26. Holt, Nina Elisabeth
    et al.
    Briand, Lionel
    Torkar, Richard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Empirical evaluations on the cost-effectiveness of state-based testing: An industrial case study2014Ingår i: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 56, nr 8, s. 890-910Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context Test models describe the expected behavior of the software under test and provide the basis for test case and oracle generation. When test models are expressed as UML state machines, this is typically referred to as state-based testing (SBT). Despite the importance of being systematic while testing, all testing activities are limited by resource constraints. Thus, reducing the cost of testing while ensuring sufficient fault detection is a common goal in software development. No rigorous industrial case studies of SBT have yet been published. Objective In this paper, we evaluate the cost-effectiveness of SBT on actual control software by studying the combined influence of four testing aspects: coverage criterion, test oracle, test model and unspecified behavior (sneak paths). Method An industrial case study was used to investigate the cost-effectiveness of SBT. To enable the evaluation of SBT techniques, a model-based testing tool was configured and used to automatically generate test suites. The test suites were evaluated using 26 real faults collected in a field study. Results Results show that the more detailed and rigorous the test model and oracle, the higher the fault-detection ability of SBT. A less precise oracle achieved 67% fault detection, but the overall cost reduction of 13% was not enough to make the loss an acceptable trade-off. Removing details from the test model significantly reduced the cost by 85%. Interestingly, only a 24–37% reduction in fault detection was observed. Testing for sneak paths killed the remaining eleven mutants that could not be killed by the conformance test strategies. Conclusions Each of the studied testing aspects influences cost-effectiveness and must be carefully considered in context when selecting strategies. Regardless of these choices, sneak-path testing is a necessary step in SBT since sneak paths are common while also undetectable by conformance testing.

  • 27. Lucas, Gren
    et al.
    Torkar, Richard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Robert, Feldt
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    The prospects of a quantitative measurement of agility: A validation study on an agile maturity model2015Ingår i: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 107, s. 38-49Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Agile development has now become a well-known approach to collaboration in professional work life. Both researchers and practitioners want validated tools to measure agility. This study sets out to validate an agile maturity measurement model with statistical tests and empirical data. First, a pretest was conducted as a case study including a survey and focus group. Second, the main study was conducted with 45 employees from two SAP customers in the US. We used internal consistency (by a Cronbach’s alpha) as the main measure for reliability and analyzed construct validity by exploratory principal factor analysis (PFA). The results suggest a new categorization of a subset of items existing in the tool and provides empirical support for these new groups of factors. However, we argue that more work is needed to reach the point where a maturity models with quantitative data can be said to validly measure agility, and even then, such a measurement still needs to include some deeper analysis with cultural and contextual items.

  • 28. Madeyski, Lech
    et al.
    Orzeszyna, Wojciech
    Torkar, Richard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Józala, Mariusz
    Overcoming the equivalent mutant problem: A systematic literature review and a comparative experiment of second order mutation2014Ingår i: IEEE Transactions on Software Engineering, ISSN 0098-5589, E-ISSN 1939-3520, Vol. 40, nr 1, s. 23-42Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context. The equivalent mutant problem (EMP) is one of the crucial problems in mutation testing widely studied over decades. Objectives. The objectives are: to present a systematic literature review (SLR) in the field of EMP; to identify, classify and improve the existing, or implement new, methods which try to overcome EMP and evaluate them. Method. We performed SLR based on the search of digital libraries. We implemented four second order mutation (SOM) strategies, in addition to first order mutation (FOM), and compared them from different perspectives. Results. Our SLR identified 17 relevant techniques (in 22 articles) and three categories of techniques: detecting (DEM); suggesting (SEM); and avoiding equivalent mutant generation (AEMG). The experiment indicated that SOM in general and JudyDiffOp strategy in particular provide the best results in the following areas: total number of mutants generated; the association between the type of mutation strategy and whether the generated mutants were equivalent or not; the number of not killed mutants; mutation testing time; time needed for manual classification. Conclusions. The results in the DEM category are still far from perfect. Thus, the SEM and AEMG categories have been developed. The JudyDiffOp algorithm achieved good results in many areas.

  • 29. Mairhofer, Stefan
    et al.
    Feldt, Robert
    Torkar, Richard
    Search-based software testing and complex test data generation in a dynamic programming language2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Manually creating test cases is time consuming and error prone. Search-based software testing can help automate this process and thus reduce time and effort and increase quality by automatically generating relevant test cases. Previous research has mainly focused on static programming languages and simple test data inputs such as numbers. This is not practical for dynamic programming languages that are increasingly used by software developers. Here we present an approach for search-based software testing for dynamically typed programming languages that can generate test scenarios and both simple and more complex test data. The approach is implemented as a tool, RuTeG, in and for the dynamic programming language Ruby. It combines an evolutionary search for test cases that give structural code coverage with a learning component to restrict the space of possible types of inputs. The latter is called for in dynamic languages since we cannot always know statically which types of objects are valid inputs. Experiments on 14 cases taken from real-world Ruby projects show that RuTeG achieves full or higher statement coverage on more cases and does so faster than randomly generated test cases.

  • 30.
    Marculescu, Bogdan
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Feldt, Robert
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Objective Re-Weighting to Guide an Interactive Search Based Software Testing System2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Even hardware-focused industries today develop products where software is both a large and important component. Engineers tasked with developing and integrating these products do not always have a software engineering background. To ensure quality, tools are needed that automate and support software testing while allowing these domain specialists to leverage their knowledge and experience. Search-based testing could be a key aspect in creating an automated tool for supporting testing activities. However, domain specific quality criteria and trade-offs make it difficult to develop a general fitness function a priori, so interaction between domain specialists and such a tool would be critical to its success. In this paper we present a system for interactive search-based software testing and investigate a way for domain specialists to guide the search by dynamically re-weighting quality goals. Our empirical investigation shows that objective reweighting can help a human domain specialist interactively guide the search, without requiring specialized knowledge of the system and without sacrificing population diversity.

  • 31.
    Marculescu, Bogdan
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Feldt, Robert
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Torkar, Richard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Practitioner-Oriented Visualization in an Interactive Search-Based Software Test Creation Tool2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Search-based software testing uses meta-heuristic search techniques to automate or partially automate testing tasks, such as test case generation or test data generation. It uses a fitness function to encode the quality characteristics that are relevant, for a given problem, and guides the search to acceptable solutions in a potentially vast search space. From an industrial perspective, this opens up the possibility of generating and evaluating lots of test cases without raising costs to unacceptable levels. First, however, the applicability of search-based software engineering in an industrial setting must be evaluated. In practice, it is difficult to develop a priori a fitness function that covers all practical aspects of a problem. Interaction with human experts offers access to experience that is otherwise unavailable and allows the creation of a more informed and accurate fitness function. Moreover, our industrial partner has already expressed a view that the knowledge and experience of domain specialists are more important to the overall quality of the systems they develop than software engineering expertise. In this paper we describe our application of Interactive Search Based Software Testing (ISBST) in an industrial setting. We used SBST to search for test cases for an industrial software module and based, in part, on interaction with a human domain specialist. Our evaluation showed that such an approach is feasible, though it also identified potential difficulties relating to the interaction between the domain specialist and the system.

  • 32.
    Marculescu, Bogdan
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Feldt, Robert
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Green, Lars-Goran
    Liljegren, Thomas
    Hult, Erika
    Flexible and Low-Cost Measurements for Space Software Development: The Measurements Exploration Framework2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Verification and validation is an important part of software development and accounts for significant amounts of the costs associated with such a project. For developers of life or mission critical systems, such as software being developed for space applications, a balance must be reached between ensuring the quality of the system by extensive and rigorous testing and reducing costs and allowing the com- pany to compete. Ensuring the quality of any system starts with a quality development process. To evaluate both the software development process and the product itself, measurements are needed. A balance must be then struck between ensuring the best possible quality of both process and product on the one hand, and reducing the cost of performing requirements on the other. A number of measurements have already been defined and are being used. For some of these, data collection can be automated as well, further lowering costs associated with implementing them. In practice, however, there may be situations where existing measurements are unsuitable for a variety of reasons. This paper describes a framework for creating low cost, flexible measurements in areas where initial information is scarce. The framework, called The Measurements Exploration Framework, is aimed in particular at the Space Software development industry and was developed is such an environment.

  • 33.
    Marculescu, Bogdan
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Feldt, Robert
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Torkar, Richard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Poulding, Simon
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    An initial industrial evaluation of interactive search-based testing for embedded software2015Ingår i: Applied Soft Computing, ISSN 1568-4946, E-ISSN 1872-9681, Vol. 29, s. 26-39Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Search-based software testing promises the ability to generate and evaluate large numbers of test cases at minimal cost. From an industrial perspective, this could enable an increase in product quality without a matching increase in the time and effort required to do so. Search-based software testing, however, is a set of quite complex techniques and approaches that do not immediately translate into a process for use with most companies. For example, even if engineers receive the proper education and training in these new approaches, it can be hard to develop a general fitness function that covers all contingencies. Furthermore, in industrial practice, the knowledge and experience of domain specialists are often key for effective testing and thus for the overall quality of the final software system. But it is not clear how such domain expertise can be utilized in a search-based system. This paper presents an interactive search-based software testing (ISBST) system designed to operate in an industrial setting and with the explicit aim of requiring only limited expertise in software testing. It uses SBST to search for test cases for an industrial software module, while also allowing domain specialists to use their experience and intuition to interactively guide the search. In addition to presenting the system, this paper reports on an evaluation of the system in a company developing a framework for embedded software controllers. A sequence of workshops provided regular feedback and validation for the design and improvement of the ISBST system. Once developed, the ISBST system was evaluated by four electrical and system engineers from the company (the ’domain specialists’ in this context) used the system to develop test cases for a commonly used controller module. As well as evaluating the utility of the ISBST system, the study generated interaction data that were used in subsequent laboratory experimentation to validate the underlying search-based algorithm in the presence of realistic, but repeatable, interactions. The results validate the importance that automated software testing tools in general, and search-based tools, in particular, can leverage input from domain specialists while generating tests. Furthermore, the evaluation highlighted benefits of using such an approach to explore areas that the current testing practices do not cover or cover insufficiently. © 2014 Elsevier B.V. All rights reserved.

  • 34.
    Marculescu, Bogdan
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Feldt, Robert
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Torkar, Rickard
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik.
    Using Exploration Focused Techniques to Augment Search-Based Software Testing: An Experimental Evaluation2016Ingår i: Proceedings - 2016 IEEE International Conference on Software Testing, Verification and Validation, ICST 2016, IEEE Computer Society, 2016, s. 69-79, artikel-id 7515460Konferensbidrag (Refereegranskat)
    Abstract [en]

    Search-based software testing (SBST) often uses objective-based approaches to solve testing problems. There are, however, situations where the validity and completeness of objectives cannot be ascertained, or where there is insufficient information to define objectives at all. Incomplete or incorrect objectives may steer the search away from interesting behavior of the software under test (SUT) and from potentially useful test cases. This papers investigates the degree to which exploration-based algorithms can be used to complement an objective-based tool we have previously developed and evaluated in industry. In particular, we would like to assess how exploration-based algorithms perform in situations where little information on the behavior space is available a priori. We have conducted an experiment comparing the performance of an exploration-based algorithm with an objective-based one on a problem with a high-dimensional behavior space. In addition, we evaluate to what extent that performance degrades in situations where computational resources are limited. Our experiment shows that exploration-based algorithms are useful in covering a larger area of the behavior space and result in a more diverse solution population. Typically, of the candidate solutions that exploration-based algorithms propose, more than 80% were not covered by their objective-based counterpart. This increased diversity is present in the resulting population even when computational resources are limited. We conclude that exploration-focused algorithms are a useful means of investigating high-dimensional spaces, even in situations where limited information and limited resources are available.

  • 35.
    Nidhra, Srinivas
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Yanamadala, Muralidhar
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Afzal, Wasif
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Knowledge transfer challenges and mitigation strategies in global software development: A systematic literature review and industrial validation2013Ingår i: International Journal of Information Management, ISSN 0268-4012, E-ISSN 1873-4707, Vol. 33, nr 2, s. 333-355Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this article we considered knowledge transfer (KT) in global software development (GSD) from two perspectives, state-of-the-art and state-of-the-practice, in order to identify what are the challenges that hamper the success of KT in global software teams, as well as to find out what are the mitigation strategies that can be used to overcome such challenges. The overall aim of this work is to provide a body of knowledge for enabling successful KT in GSD settings. This is achieved by an in-depth understanding of KT challenges and mitigation strategies, both from the perspective of literature and industry. It also identifies the similarities and differences in challenges and strategies gathered from literature studies and industrial experts.

  • 36.
    Pelto-Piri, Johannes
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Molin, Peter
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    A unified model for server usage and operational costs based on user profiles: An industrial evaluation2012Konferensbidrag (Refereegranskat)
  • 37. Radjenović, Danijel
    et al.
    Heričko, Marjan
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Živkovič, Aleš
    Software fault prediction metrics: A systematic literature review2013Ingår i: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 55, nr 8, s. 1397-1418Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Software metrics may be used in fault prediction models to improve software quality by predicting fault location. Objective: This paper aims to identify software metrics and to assess their applicability in software fault prediction. We investigated the influence of context on metrics' selection and performance. Method: This systematic literature review includes 106 papers published between 1991 and 2011. The selected papers are classified according to metrics and context properties. Results: Object-oriented metrics (49%) were used nearly twice as often compared to traditional source code metrics (27%) or process metrics (24%). Chidamber and Kemerer's (CK) object-oriented metrics were most frequently used. According to the selected studies there are significant differences between the metrics used in fault prediction performance. Object-oriented and process metrics have been reported to be more successful in finding faults compared to traditional size and complexity metrics. Process metrics seem to be better at predicting post-release faults compared to any static code metrics. Conclusion: More studies should be performed on large industrial software systems to find metrics more relevant for the industry and to answer the question as to which metrics should be used in a given context.

  • 38. Riņķevič, Kaspars
    et al.
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Equality in cumulative voting: A systematic review with an improvement proposal2013Ingår i: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 55, nr 2, s. 267-287Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context: Prioritization is an essential part of requirements engineering, software release planning and many other software engineering disciplines. Cumulative Voting (CV) is known as a relatively simple method for prioritizing requirements on a ratio scale. Historically, CV has been applied in decision-making in government elections, corporate governance, and forestry. However, CV prioritization results are of a special type of data-compositional data. Objectives: The purpose of this study is to aid decision-making by collecting knowledge on the empirical use of CV and develop a method for detecting prioritization items with equal priority. Methods: We present a systematic literature review of CV and CV analysis methods. The review is based on searching electronic databases and snowball sampling of the found primary studies. Relevant studies are selected based on titles, abstracts, and full text inspection. Additionally, we propose Equality of Cumulative Votes (ECVs)-a CV result analysis method that identifies prioritization items with equal priority. Results: CV has been used in not only requirements prioritization and release planning but also in e.g. software process improvement, change impact analysis and model driven software development. The review presents a collection of state of the practice studies and CV result analysis methods. In the end, ECV was applied to 27 prioritization cases from 14 studies and identified nine groups of equal items in three studies. Conclusions: We believe that the analysis of the collected studies and the CV result analysis methods can help in the adoption of CV prioritization method. The evaluation of ECV indicates that it is able to detect prioritization items with equal priority and thus provide the practitioner with a more fine-grained analysis.

  • 39. Rogstad, Erik
    et al.
    Briand, Lionel
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Test Case Selection for Black-Box Regression Testing of Database Applications2013Ingår i: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 55, nr 10, s. 1781-1795Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context: This paper presents an approach for selecting regression test cases in the context of large-scale, database applications. We focus on a black-box (specification-based) approach, relying on classification tree models to model the input domain of the system under test (SUT), in order to obtain a more practical and scalable solution. We perform an industrial case study where the SUT is a large database application in Norway’s tax department. Objective: We investigate the use of similarity-based test case selection for supporting black box regression testing of database applications. We have developed a practical approach and tool (DART) for functional black-box regression testing of database applications. In order to make the regression test approach scalable for large database applications, we needed a test case selection strategy that reduces the test execution costs and analysis e ort. We used classification tree models to partition the input domain of the SUT in order to then select test cases. Rather than selecting test cases at random from each partition, we incorporated a similarity-based test case selection, hypothesizing that it would yield a higher fault detection rate. Method: An experiment was conducted to determine which similarity-based selection algorithm was the most suitable in selecting test cases in large regression test suites, and whether similarity-based selection was a worthwhile and practical alternative to simpler solutions. Results: The results show that combining similarity measurement with partition-based test case selection, by using similarity-based test case selection within each partition, can provide improved fault detection rates over simpler solutions when specific conditions are met regarding the partitions. Conclusions: Under the conditions present in the experiment the improvements were marginal. However, a detailed analysis concludes that the similarity-based selection strategy should be applied when a large number of test cases are contained in each partition and there is significant variability within partitions. If these conditions are not present, incorporating similarity measures is not worthwhile, since the gain is negligible over a random selection within each partition.

  • 40. Schneider, Stefan
    et al.
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Gorschek, Tony
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Solutions in Global Software Engineering: A Systematic Literature Review2013Ingår i: International Journal of Information Management, ISSN 0268-4012, E-ISSN 1873-4707, Vol. 33, nr 1, s. 119-132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Global software engineering (GSE) has received increased attention, as globalization enables and encourages increased distribution of product development. Many empirical studies and systematic literature reviews (SLRs) focus on the identification of challenges, this paper however presents the first SLR collecting and analyzing solutions associated with GSE, while also evaluating the level of empirical validation of said solutions. As a starting point the paper presents a GSE model, designed to categorize solutions into process areas, useful for the analysis of the research community's contributions to state-of-the-art and identifying fundamental gaps in research. In addition, the model categorizing the solutions is populated with references and good-examples, useful for practitioners, which can use the model to find solutions to overall challenges in various process areas. The overall results of the systematic review revealed more than 330 papers containing 127 solutions that were then identified and mapped to the model. The process areas of project management are highly populated, while other areas like product integration have received surprisingly little attention. In addition, selected process area is elaborated upon in terms of contents and deficiencies.

  • 41. Svahnberg, Mikael
    et al.
    Gorschek, Tony
    Feldt, Robert
    Torkar, Richard
    Saleem, S.B
    Shafique, M.U.
    A systematic review on strategic release planning models2010Ingår i: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 52, nr 3, s. 237-248Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Strategic release planning (sometimes referred to as road-mapping) is an important phase of the requirements engineering process performed at product level. It is concerned with selection and assignment of requirements in sequences of releases such that important technical and resource constraints are fulfilled. Objectives: In this study we investigate which strategic release planning models have been proposed, their degree of empirical validation, their factors for requirements selection, and whether they are intended for a bespoke or market-driven requirements engineering context. Methods: In this systematic review a number of article sources are used, including Compendex, Inspec, IEEE Xplore, ACM Digital Library, and Springer Link. Studies are selected after reading titles and abstracts to decide whether the articles are peer reviewed, and relevant to the subject. Results: Twenty four strategic release planning models are found and mapped in relation to each other, and a taxonomy of requirements selection factors is constructed. Conclusions: We conclude that many models are related to each other and use similar techniques to address the release planning problem. We also conclude that several requirement selection factors are covered in the different models, but that many methods fail to address factors such as stakeholder value or internal value. Moreover, we conclude that there is a need for further empirical validation of the models in full scale industry trials. © 2009 Elsevier B.V. All rights reserved.

  • 42. Svensson, Richard Berntsson
    et al.
    Gorschek, Tony
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Regnell, Björn
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Shahrokni, Ali
    Feldt, Robert
    Quality Requirements in Industrial Practice – An Extended Interview Study at Eleven Companies2012Ingår i: IEEE Transactions on Software Engineering, ISSN 0098-5589, E-ISSN 1939-3520, Vol. 38, nr 4, s. 923-935Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to create a successful software product and assure its quality, it is not enough to fulfill the functional requirements, it is also crucial to find the right balance among competing quality requirements (QR). An extended, previosluy piloted, interview study was performed to identify specific challenges associated with the selection, trade-off, and management of QR in industrial practice. Data was collected through semi-structured interviews with eleven product managers and eleven project leaders from eleven software companies. The contribution of this study is fourfold: First, it compares how QR are handled in two cases, companies working in business-to-business markets, and companies that are working in business-to-consumer markets. These two are also compared in terms of impact on the handling of QRs. Second, it compares the perceptions and priorities of QR by product and project management respectively. Third, it includes an examination of the interdependencies among quality requirements perceived as most important by the practitioners. Fourth, it characterizes the selection and management of QR in down-stream development activities.

  • 43. Svensson, Richard Berntsson
    et al.
    Gorschek, Tony
    Regnell, Björn
    Torkar, Richard
    Shahrokni, Ali
    Feldt, Robert
    Aurum, Aybüke
    Prioritization of quality requirements: State of practice in eleven companies2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Requirements prioritization is recognized as an important but challenging activity in software product development. For a product to be successful, it is crucial to find the right balance among competing quality requirements. Although literature offers many methods for requirements prioritization, the research on prioritization of quality requirements is limited. This study identifies how quality requirements are prioritized in practice at 11 successful companies developing software intensive systems. We found that ad-hoc prioritization and priority grouping of requirements are the dominant methods for prioritizing quality requirements. The results also show that it is common to use customer input as criteria for prioritization but absence of any criteria was also common. The results suggests that quality requirements by default have a lower priority than functional requirements, and that they only get attention in the prioritizing process if decision-makers are dedicated to invest specific time and resources on QR prioritization. The results of this study may help future research on quality requirements to focus investigations on industry-relevant issues.

  • 44. Torkar, Richard
    Empirical Studies of Software Black Box Testing Techniques: Evaluation and Comparison2004Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Software is today used in more and different ways than ever before. From refrigerators and cars to space shuttles and smart cards. As such, most software, usually need to adhere to a specification. Normally, a software engineer goes through a certain process to establish that the software follows a given specification. This process, verification and validation (V & V), ensures that the software conforms to its specification and that the customers ultimately receives what they ordered. Software testing is one of the techniques to use in V & V. Software testing has evolved during the last decades since e.g. programming languages, software and requirement specification designs all have evolved likewise. Nevertheless, when we examine how software testing is used today, particularly in small- and medium-sized enterprises with their limited resources and in some cases limited knowledge, there is clearly room for improvements. Not seldom, software testing is the first thing being disregarded when deadlines creep closer. To be able to use resources in a better way, computers should be able to help out in the art of software testing much more, than is currently the case today. Unfortunately, the automatization benefits with respect to software testing have not been clearly visable, even though some progress have been made. In this thesis we initially look at the current state of practice when it comes to software testing by presenting the results of a survey. Next, we evaluate what the findings would mean for software engineers, by performing an exploratory study whereas we examine the reliability aspects of the survey. Finally, we examine the usage of different black-box methodologies and their potential use in automatization aspects. In addition, theories improving quality estimations while using one black-box technique, is presented and evaluated. We argue that there is a potential interest and advantage in using different blackbox methodologies, formalizing and improving them even more while finally adding them to the field of automatization, hence in the end saving both time and money for companies.

  • 45. Torkar, Richard
    Towards Automated Software Testing: Techniques, Classifications and Frameworks2006Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Software is today used in more and different ways than ever before. From refrigerators and cars to space shuttles and smart cards. As such, most software, usually need to adhere to a specification, i.e. to make sure that it does what is expected. Normally, a software engineer goes through a certain process to establish that the software follows a given specification. This process, verification and validation (V & V), ensures that the software conforms to its specification and that the customers ultimately receive what they ordered. Software testing is one of the techniques to use during V & V. To be able to use resources in a better way, computers should be able to help out in the “art of software testing” to a higher extent, than is currently the case today. One of the issues here is not to remove human beings from the software testing process altogether—in many ways software development is still an art form and as such pose some problems for computers to participate in—but instead let software engineers focus on problems computers are evidently bad at solving. This dissertation presents research aimed at examining, classifying and improving the concept of automated software testing and is built upon the assumption that software testing could be automated to a higher extent. Throughout this thesis an emphasis has been put on “real life” applications and the testing of these applications. One of the contributions in this dissertation is the research aimed at uncovering different issues with respect to automated software testing. The research is performed through a series of case studies and experiments which ultimately also leads to another contribution—a model for expressing, clarifying and classifying software testing and the automated aspects thereof. An additional contribution in this thesis is the development of framework desiderata which in turns acts as a broad substratum for a framework for object message pattern analysis of intermediate code representations. The results, as presented in this dissertation, shows how software testing can be improved, extended and better classified with respect to automation aspects. The main contribution lays in the investigation of, and the improvement in, issues related to automated software testing.

  • 46. Torkar, Richard
    et al.
    Awan, Nasir Majeed
    Alvi, Adnan Khadem
    Afzal, Wasif
    Predicting Software Test Effort in Iterative Development Using a Dynamic Bayesian Network2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Projects following iterative software development methodologies must still be managed in a way as to maximize quality and minimize costs. However, there are indications that predicting test effort in iterative development is challenging and currently there seem to be no models for test effort prediction. This paper introduces and validates a dynamic Bayesian network for predicting test effort in iterative software devel- opment. The proposed model is validated by the use of data from two industrial projects. The accuracy of the results has been verified through different prediction accuracy measurements and statistical tests. The results from the validation confirm that the model has the ability to predict test effort in iterative projects accurately.

  • 47. Torkar, Richard
    et al.
    Feldt, Robert
    Gorschek, Tony
    Extracting Generally Applicable Patterns from Object-Oriented Programs for the Purpose of Software Test Creation2008Konferensbidrag (Refereegranskat)
  • 48. Torkar, Richard
    et al.
    Feldt, Robert
    Gorschek, Tony
    Extracting generally applicable patterns from object-oriented programs for the purpose of test case creation2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents an experiment performed on three large open source applications. The applications were instrumented automatically with a total of 10,494 instrumentation points. The purpose of the instrumentation was to collect and store data during the execution of each application that later could be analyzed off-line. Data analysis, on the collected data, allowed for the creation of test cases (test data, test fixtures and test evaluators) in addition to finding object message patterns for object-oriented software.

  • 49. Torkar, Richard
    et al.
    Gorschek, Tony
    Feldt, Robert
    Eighth Conference on Software Engineering Research and Practice in Sweden (SERPS'08)2009Ingår i: Software Engineering Notes: an Informal Newsletter of The Specia, ISSN 0163-5948, E-ISSN 1943-5843, Vol. 34, nr 2, s. 31-33Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The eight conference on software engineering research and practice in Sweden (SERPS'08) was held in Karlskrona, Sweden, on the 4th-5th of Nov. 2008. The aim with SERPS'08 is to bring researchers and industry practitioners together to discuss software engineering issues, problems, solutions and experiences, not necessarily from a Swedish perspective. During the conference a number of research and industry papers were presented and questions in connection to the presentations were discussed. This paper is a report on the discussions that took place, pointing towards needs and challenges as well as areas of interest in both academia and industry.

  • 50.
    Torkar, Richard
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Gorschek, Tony
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Feldt, Robert
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Svahnberg, Mikael
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Uzair Akbar, Raja
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Kamran, Kashif
    Requirements Traceability: A Systematic Review and Industry Case Study2012Ingår i: International Journal of Software Engineering and Knowledge Engineering, ISSN 0218-1940, Vol. 22, nr 3, s. 385-433Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Requirements traceability enables software engineers to trace a requirement from its emergence to its fulfillment. In this paper we examine requirements traceability definitions, challenges, tools and techniques, by the use of a systematic review performing an exhaustive search through the years 1997-2007. We present a number of common definitions, challenges, available tools and techniques (presenting empirical evidence when found), while complementing the results and analysis with a static validation in industry through a series of interviews.

12 1 - 50 av 52
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