05 Fakultät Informatik, Elektrotechnik und Informationstechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/6
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Item Open Access Assessing iterative practical software engineering courses with play money(2016) Mindermann, Kai; Ostberg, Jan-Peter; Wagner, StefanChanging our practical software engineering course from the previous waterfall model to a more agile and iterative approach created more severe assessment challenges. To cope with them we added an assessment concept based on play money. The concept not only includes weekly expenses to simulate real running costs but also investments, which correspond to assessment results of the submissions. This concept simulates a startup-like working environment and its financing in an university course. Our early evaluation shows that the combination of the iterative approach and the play money investments is motivating for many students. At this point we think that the combined approach has advantages from both the supervising and the students point of view. We planned more evaluations to better understand all its effects.Item Open Access Are suggestions of coupled file changes interesting?(2016) Ramadani, Jasmin; Wagner, StefanSoftware repositories include information which can be made available for bug fixing or maintenance using repository mining. The identification of coupled changes have been proposed several times. Yet, existing studies focus on the found couplings and ignore feedback from developers. We investigate three development projects and their repositories to find files that frequently change together to support the software developers. We complement the coupled files information with details from the issue tracking system and the project documentation. We contrast our findings with feedback from the developers about how interesting our findings are for them. We found that the small size of the repositories made an insightful analysis difficult. The response to coupled changes both from experienced and inexperienced developers was mostly neutral. They accepted most of the additional attributes we presented. Furthermore, developers also suggested other additional issues to be relevant, e.g. the context of the coupled changes and the way they are presented, which we did not cover in this study. Therefore, coupled change analysis research will need to take the presentation and context information into account.Item Open Access Empirical research plan: effects of sketching on program comprehension(2016) Baltes, Sebastian; Wagner, StefanSketching is an important means of communication in software engineering practice. Yet, there is little research investigating the use of sketches. We want to contribute a better understanding of sketching, in particular its use during program comprehension. We propose a controlled experiment to investigate the effectiveness and efficiency of program comprehension with the support of sketches as well as what sketches are used in what way.Item Open Access Mining Java packages for developer profiles : an exploratory study(2017) Ramadani, Jasmin; Wagner, StefanItem Open Access Towards applying a safety analysis and verification method based on STPA to agile software development(2016) Wang, Yang; Wagner, StefanThis paper presents a novel agile process model "S-Scrum" based on the existing development process "Safe Scrum" and extended by a safety analysis method and a safety verification approach based on STPA (System-Theoretic Process Analysis).Item Open Access Interdisciplinary system courses - teaching agile systems engineering(2019) Seitz, Andreas; Avezum, Mariana; Bruegge, Bernd; Wagner, StefanWith the advent of technologies like the Internet of Things, Industry 4.0 and Cyber-Physical Systems, many software engineering courses turn into system engineering courses. Recent advances in technologies such as 3D printing and low-cost micro controllers enable to teach agile hard- and software co-design in system engineering courses. In this paper, we describe Interdisciplinary System Courses (ISC) - a teaching approach based on interdisciplinary projects, light-weight agile techniques and solving real problems by integrating industry customers. We describe our experiences from an exploratory case study where we applied ISC in a two-week international summer school with a customer from the aerospace industry. We derive a set of hypotheses on the effects of ISC.Item Open Access How do coupled file changes influence how developers seek help during maintenance tasks?(2017) Ramadani, Jasmin; Wagner, StefanSoftware repositories contain a lot of information that can be transformed into suggestions other files they need to modify during maintenance tasks (so-called “coupled changes”). Existing studies however ignore developer feedback and their influence on the developer strategy for getting help during maintenance tasks. We used the Grounded Theory approach to investigate screen capture videos from an experiment to find which information sources developers use to find help and what is their relevance. We compared the frequency as well as the sequence patterns of used information sources both for the developers using coupled change suggestions and those not using them. We found a set of information sources where the developers seek for help and identified two categories of relevance. Also, we discovered that for the tasks using coupled change suggestions, the developers used mostly the internal IDE elements as an information source whereby the developers not using coupled change suggestions often used external sources like the documentation or the web. Coupled change suggestions influence the strategy how the developers seek for help by reducing the search for information on external locations which makes the process of solving maintenance tasks more compact.Item Open Access XSTAMPP 2.0: new improvements to XSTAMPP Including CAST accident analysis and an extended approach to STPA(2016) Abdulkhaleq, Asim; Wagner, StefanXSTAMPP (eXtensible STAMP Platform ) is a software tool developed to serve the widespread adoption and use of STAMP methodologies in different domains. The first version of XSTAMPP supported only the STPA application. In this paper, we present a new version of XSTAMPP, including CAST accident analysis and extended approach to STPA. We developed two new plug-in tools called (1) A-CAST (Automated CAST) which implements the CAST activities and (2) XSTPA (Extended Approach to STPA) which supports automatically generating the context tables which will be used to refine the safety requirements and automatically transform the refined safety requirements into a formal specification in Linear Temporal Logic (LTL) to support verification activities. XSTAMPP 2.0 is available as an open source platform at our repository http://sourceforge.net/projects/stampp/files/2.0.0/.Item Open Access Will my tests tell me if I break this code?(2016) Niedermayr, Rainer; Juergens, Elmar; Wagner, StefanAutomated tests play an important role in software evolution because they can rapidly detect faults introduced during changes. In practice, code-coverage metrics are often used as criteria to evaluate the effectiveness of test suites with focus on regression faults. However, code coverage only expresses which portion of a system has been executed by tests, but not how effective the tests actually are in detecting regression faults. Our goal was to evaluate the validity of code coverage as a measure for test effectiveness. To do so, we conducted an empirical study in which we applied an extreme mutation testing approach to analyze the tests of open-source projects written in Java. We assessed the ratio of pseudo-tested methods (those tested in a way such that faults would not be detected) to all covered methods and judged their impact on the software project. The results show that the ratio of pseudo-tested methods is acceptable for unit tests but not for system tests (that execute large portions of the whole system). Therefore, we conclude that the coverage metric is only a valid effectiveness indicator for unit tests.Item Open Access Which change sets in Git repositories are related?(2016) Ramadani, Jasmin; Wagner, Stefan