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 Software-Prüfung : eine Fibel(1991) Frühauf, Karol; Ludewig, Jochen; Sandmayr, HelmutDieses Buch soll die wichtigsten Grundsätze der Software-Prüfung vermitteln. Wir betrachten dabei vor allem die Aktivitäten der Beteiligten, weniger die technischen Hilfsmittel. Es richtet sich an alle, die als Entwickler, Kunden oder Vorgesetzte mit der Prüfung und Qualitätssicherung von Software befaßt sind. Ziel der Autoren ist es, wenige, aber praktikable Möglichkeiten zu zeigen, wie man wirklich vorgehen kann - und nach dem Stand der Technik verfahren sollte. Wir wenden uns also nicht an erfahrene Testspezialisten, deren Vorkenntnisse über den Anspruch dieses Buchs hinausgehen. Vielmehr haben wir uns bemüht, das Elementare in leicht anwendbarer Form zusammenzustellen.Item Open Access Aufgaben zum Skriptum Informatik. 2., durchgesehene Auflage(1994) Spiegel, André; Ludewig, Jochen; Appelrath, Hans-JürgenDieses Buch enthält eine Sammlung von Aufgaben, wie sie typischerweise in Übungen und Prüfungen zur Einführungsvorlesung in die Informatik gestellt werden. Es ist speziell abgestimmt auf das bereits erschienene Lehrbuch von Appelrath und Ludewig (im Rest des Buches kurz "Skriptum" genannt) und soll dem Lernenden helfen, den umfangreichen Stoff aktiv aufzuarbeiten. Der beste Weg dazu ist, die neuen Konzepte und Vorgehensweisen selbst anzuwenden. Bei der Auswahl und Überarbeitung der Aufgaben wurde besonders auf eine genaue Orientierung am Skriptum geachtet, angefangen bei vordergründigen Dingen wie dem Layout und der Reihenfolge der Themen bis hin zu den verwendeten Begriffen und dem Umfang des Stoffes. Das Skriptum wird hier durch Aufgaben illustriert; nicht mehr und kaum weniger als der Stoff des Skriptums wird vorausgesetzt.Item Open Access Towards building knowledge on causes of critical requirements engineering problems(2015) Kalinowski, Marcos; Spínola, Rodrigo Oliveira; Conte, Tayana; Prikladnicki, Rafael; Méndez Fernández, Daniel; Wagner, Stefan[Context] Many software projects fail due to problems in requirements engineering (RE). [Objective] The goal of this paper is to gather information on relevant RE problems and to represent knowledge on their most common causes. [Method] We replicated a global family of RE surveys in the Brazil and used the data to identify critical RE problems and to build probabilistic cause-effect diagrams to represent knowledge on their common causes. [Results] The survey was answered by 74 different organizations, including small, medium and very large sized companies, conducting both, plan-driven and agile development. The most critical RE problems, according to those organizations, are related to communication and to incomplete or underspecified requirements. We provide the full probabilistic cause-effect diagrams with knowledge on common causes of the most critical identified RE problems online. [Conclusion] We believe that the knowledge presented in the diagrams can be helpful to support organizations in conducting causal analysis sessions by providing an initial understanding on what usually causes critical RE problems.Item Open Access Where do we stand in requirements engineering improvement today? : first results from a mapping study(2014) Méndez Fernández, Daniel; Ognawala, Saahil; Wagner, Stefan; Daneva, MayaRequirements engineering process improvement (REPI) approaches have gained much attention in research and practice. So far, however, there is no comprehensive view on the research in REPI in terms of solutions and current state of reported evidence. This paper aims to provide an overview on the existing solutions, their underlying principles and their research type facets, i.e. their state of empirical evidence. To this end, we conducted a systematic mapping study of the REPI publication space. This paper reports on the first findings regarding research type facets of the contributions as well as selected methodological principles. We found a strong focus in the existing research on solution proposals for REPI approaches that concentrate on normative assessments and benchmarks of the RE activities rather than on holistic RE improvements according to individual goals of companies. We conclude, so far, that there is a need to broaden the work and to investigate more problem-driven REPI which also targets the improvement of the quality of the underlying RE artefacts.Item Open Access Naming the pain in requirements engineering: a design for a global family of surveys and first results from Germany(2015) Méndez Fernández, Daniel; Wagner, StefanContext: For many years, we have observed industry struggling in defining a high quality requirements engineering (RE) and researchers trying to understand industrial expectations and problems. Although we are investigating the discipline with a plethora of empirical studies, they still do not allow for empirical generalisations. Objective: To lay an empirical and externally valid foundation about the state of the practice in RE, we aim at a series of open and reproducible surveys that allow us to steer future research in a problem-driven manner. Method: We designed a globally distributed family of surveys in joint collaborations with different researchers and completed the first run in Germany. The instrument is based on a theory in the form of a set of hypotheses inferred from our experiences and available studies. We test each hypothesis in our theory and identify further candidates to extend the theory by correlation and Grounded Theory analysis. Results: In this article, we report on the design of the family of surveys, its underlying theory, and the full results obtained from Germany with participants from 58 companies. The results reveal, for example, a tendency to improve RE via internally defined qualitative methods rather than relying on normative approaches like CMMI. We also discovered various RE problems that are statistically significant in practice. For instance, we could corroborate communication flaws or moving targets as problems in practice. Our results are not yet fully representative but already give first insights into current practices and problems in RE, and they allow us to draw lessons learnt for future replications. Conclusion: Our results obtained from this first run in Germany make us confident that the survey design and instrument are well-suited to be replicated and, thereby, to create a generalisable empirical basis of RE in practice.Item Open Access Introduction of static quality analysis in small- and medium-sized software enterprises: experiences from technology transfer(2014) Gleirscher, Mario; Golubitskiy, Dmitriy; Irlbeck, Maximilian; Wagner, StefanToday, small- and medium-sized enterprises (SMEs) in the software industry face major challenges. Their resource constraints require high efficiency in development. Furthermore, quality assurance (QA) measures need to be taken to mitigate the risk of additional, expensive effort for bug fixes or compensations. Automated static analysis (ASA) can reduce this risk because it promises low application effort. SMEs seem to take little advantage of this opportunity. Instead, they still mainly rely on the dynamic analysis approach of software testing. In this article, we report on our experiences from a technology transfer project. Our aim was to evaluate the results static analysis can provide for SMEs as well as the problems that occur when introducing and using static analysis in SMEs. We analysed five software projects from five collaborating SMEs using three different ASA techniques: code clone detection, bug pattern detection and architecture conformance analysis. Following the analysis, we applied a quality model to aggregate and evaluate the results. Our study shows that the effort required to introduce ASA techniques in SMEs is small (mostly below one person-hour each). Furthermore, we encountered only few technical problems. By means of the analyses, we could detect multiple defects in production code. The participating companies perceived the analysis results to be a helpful addition to their current QA and will include the analyses in their QA process. With the help of the Quamoco quality model, we could efficiently aggregate and rate static analysis results. However, we also encountered a partial mismatch with the opinions of the SMEs. We conclude that ASA and quality models can be a valuable and affordable addition to the QA process of SMEs.Item Open Access Does outside-in teaching improve the learning of object-oriented programming?(2015) Janke, Erica; Brune, Philipp; Wagner, StefanObject-oriented programming (OOP) is widely used in the software industry and university introductory courses today. Following the structure of most textbooks, such courses frequently are organised starting with the concepts of imperative and structured programming and only later introducing OOP. An alternative approach is to begin directly with OOP following the Outside-In teaching method as proposed by Meyer. Empirical results for the effects of Outside-In teaching on students and lecturers are sparse, however. We describe the conceptual design and empirical evaluation of two OOP introductory courses from different universities based on Outside-In teaching. The evaluation results are compared to those from a third course serving as the control group, which was taught OOP the "traditional" way. We evaluate the initial motivation and knowledge of the participants and the learning outcomes. In addition, we analyse results of the end- term exams and qualitatively analyse the results of interviews with the lecturers and tutors. Regarding the learning outcomes, the results show no signif- icant differences between the Outside-In and the “traditional” teaching method. In general, students found it harder to solve and implement algorithmic problems than to understand object oriented (OO) concepts. Students taught OOP by the Outside-In method, however, were less afraid that they would not pass the exam at the end of term and understood the OO paradigm more quickly. Therefore, the Outside-In method is no silver bullet for teaching OOP regarding the learning outcomes but has positive effects on motivation and interest.Item Open Access What do practitioners vary in using scrum?(2015) Diebold, Philipp; Ostberg, Jan-Peter; Wagner, Stefan; Zendler, UlrichBackground: Agile software development has become a popular way of developing software. Scrum is the most frequently used agile framework, but it is often reported to be adapted in practice. Objective: Thus, we aim to understand how Scrum is adapted in different contexts and what are the reasons for these changes. Method: Using a structured interview guideline, we interviewed ten German companies about their concrete usage of Scrum and analysed the results qualitatively. Results: All companies vary Scrum in some way. The least variations are in the Sprint length, events, team size and requirements engineering. Many users varied the roles, effort estimations and quality assurance. Conclusions: Many variations constitute a substantial deviation from Scrum as initially proposed. For some of these variations, there are good reasons. Sometimes, however, the variations are a result of a previous non-agile, hierarchical organisation.Item Open Access Preventing incomplete/hidden requirements: reflections on survey data from Austria and Brazil(2015) Kalinowski, Marcos; Felderer, Michael; Conte, Tayana; Spinola, Rodrigo; Prikladnicki, Rafael; Winkler, Dietmar; Méndez Fernández, Daniel; Wagner, Stefan[Context] Many software projects fail due to problems in requirements engineering (RE). [Goal] The goal of this paper is analyzing a specific and relevant RE problem in detail: incomplete/hidden requirements. [Method] We replicated a global family of RE surveys with representatives of software organizations in Austria and Brazil. We used the data to (a) characterize the criticality of the selected RE problem, and to (b) analyze the reported main causes and mitigation actions. Based on the analysis, we discuss how to prevent the problem. [Results] The survey includes 14 different organizations in Austria and 74 in Brazil, including small, medium and large sized companies, conducting both, plan-driven and agile development processes. Respondents from both countries cited the incomplete/hidden requirements problem as one of the most critical RE problems. We identified and graphically represented the main causes and documented solution options to address these causes. Further, we compiled a list of reported mitigation actions. [Conclusions] From a practical point of view, this paper provides further insights into common causes of incomplete/hidden requirements and on how to prevent this problem.Item Open Access SESAM - simulating software projects(1992) Ludewig, Jochen; Bassler, Thomas; Deininger, Marcus; Schneider, Kurt; Schwille, JürgenTeaching software engineering as well as researching in this area is very tedious due to the length and costliness of software projects. SESAM (Software Engineering Simulation by Animated Models') therefore is designed as a simulator for software projects, allowing students to gain reality-like experiences in project management and researchers to evaluate hypotheses on the mechanisms influencing software projects. This paper focuses on the basic assumptions for SESAM, its building blocks and the way hypotheses are affecting the simulation. After a short description of the requirements for SESAM, the authors introduce objects, attributes, actions, relationships between objects, and hypotheses as its basic concepts. They present attributed graph grammars as a means for representing hypotheses. Finally they position their project with respect to related work, and they show its present a state and future development.