Contributions published at Requirements Engineering (Martin Glinz)

Today the number of mobile applications and its users have dramatically increased and mobile applications have become the integral part of daily online activities now. User involvement has undergone significant changes in the last 3 years. For instance, software users transformed from being trained technical staff or programmers to any person, bringing about a basic shift in the developer’s attitude. Such changes have widened the distance existing between the users and developers with most of them focusing on the users to fulfill their demands. The main objective of this study is to explore the existing end-user feedback platforms for mobile applications and develop an end-user mobile feedback platform aligned with both user and developers aspects. The study has developed and implemented a web based end-user mobile feedback application and has conducted a deep analysis of the current situation by reflecting the uniqueness of the application developed. The findings have been collected via the case study approach and the secondary resources review.

FlexiSketch as a mobile touch-based application is ideal for initial modeling drafts, eliminating the need to copy from whiteboard or paper to a digital device. In order to reuse as much of the information already contained in FlexiSketch models as possible, we developed an export function which allows the transfer of both model and inferred metamodel to a powerful metamodeling tool. We compared various modeling and metamodeling tools as well as different metamodeling languages. Our proof-of-concept enables exporting from FlexiSketch to MetaEdit+ compatible files. We analyzed differences in the metamodeling approaches between FlexiSketch and MetaEdit+. We propose further evaluation to determine the value of this integration into the metamodeling toolchain.

Requirements elicitation is the first step in Requirements engineering (RE). In the elicitation process, involving stakeholders is the fundament for the development of a software system. Despite the large number of different elicitation methods available, these methods are not sufficient for eliciting requirements from stakeholders outside organizational reach. One approach to address this challenge that has increasingly been raising attention among RE researchers is to apply game-based methods in the elicitation process. The work presented in this paper helps to evaluate a game-based method that is going to be developed in the Requirements Engineering Research Group, against current elicitation methods in the context of stakeholders outside organizational reach. The contribution of this paper is two-folded. On the one hand we identified key aspects for the questionnaire design, which will be conducted in a further step. On the other hand we determined first requirements for the planned software system.

Social networks have changed our daily life and they have the potential to significantly influence and support Requirements Engineering (RE) activities. Social network-based RE approaches will allow us to overcome limitations of traditional approaches and allow end users to play a more prominent role in RE. They are key stakeholders in many software projects. However, involving end users is challenging, particularly when they are not within organizational reach. The goal of our work is to increase end user involvement in RE. In this paper we present an approach where we harness a social network to perform RE activities such as elicitation, prioritization and negotiation. Our approach was applied in three studies where students used Facebook to actively participate in RE activities of different projects. Although there are limitations, the results show that a popular social network site can support distributed RE.

Shared understanding is essential for efficient software engineering when the risk of unsatisfactory outcome and rework of project results shall be low. Today, however, shared understanding is used mostly in an unreflected, ad-hoc way. This affects the quality of the engineered software solutions and generates re-work once the quality problems are discovered. In this article, we investigate the role, value, and usage of shared understanding in software engineering. We contribute a reflected analysis of the problem, in particular of how to rely on shared understanding that is implicit, rather than explicit. After an overview of the state of the art we discuss forms and value of shared understanding in software engineering, survey enablers and obstacles, compile existing practices for dealing with shared understanding, and present a roadmap for improving knowledge and practice in this area.

Getting feedback from users of a mobile app is a challenging task. But listen to your user's needs is essential when building a market-oriented software and could well be the key for success. It is important to ensure that a certain amount of feedback is collected while users should not get annoyed or even lost. When introducing feedback mechnisms directly into the app one has to deal with the characteristics of a mobile device with its advantages and disadvantages. In this thesis the difficulties which come with feedback mechanisms for mobile apps are described alongside the importance and benefits of introducing feedback mechanisms to listen to your users and elicit requirements with the help of them. Multiple possibilities of getting feedback from mobile app users are compared with the strengths and weaknesses of each analysed. A feedback process and an approach for in-app feedback is shown and the results of the application of it in a real project are discussed. The evaluation of the in-app feedback mechanisms showed that end-user feedback can be very valuable to detect problems or find out which new features users wish. But it was also revealed that it is difficult to get user to sent feedbacks.

Systematic variability management is an important prerequisite for successful software reuse. However, it requires significant effort and extensive domain knowledge to document and maintain information on variability. In this paper we present a tool-supported approach which supports semi-automatically inferring variability information from customized standard software products. The approach does not only enable the identification and documentation of variability information based on existing products, it is also capable of incrementally updating this information. To guarantee quick access to reusable code artifacts (e.g. requirements, features or software components), the presented solution stores these artifacts together with related requirements and a generated variability model in an asset repository. The tool- supported approach has been applied to customizations of Microsoft Dynamics AX ERP systems. Our experiences highlight the potential and benefits of our approach compared to manually gathering information on software variability.

Requirements engineering (RE) is widely recognized as a crucial factor for the success of software projects. Therefore, companies often request assessments of RE processes and resulting artifacts to identify issues and improvement potential. However, industry claims that current assessment approaches do not always fulfill their needs regarding efficiency and effectiveness. Motivated by needs of both, companies asking for an assessment, and a company in the role of an assessor, we have developed a lightweight, tool-supported RE assessment approach. Apart from presenting the approach, we also discuss early experiences we gained from applying our assessment approach in real-world industrial projects.

Communication between requirements engineering and other disciplines, such as development and testing, is essential for successful software development. Conversely, the lack of communication, or the occurrence of so-called communication gaps, affects the success of a project often negatively. While communication gaps themselves have been studied and categorized into geographical, sociocultural, temporal, and more groups, their relation to project parameters has not yet received the same attention. Acquiring this knowledge may contribute positively to the risk management in future software projects. With the present thesis, we aim at providing answers by analysing the correlations between communication gaps and the characteristics of twelve real-world software projects. The findings are based on data ollected through interviews and surveys conducted with selected project personnel. Our main results are the following: First, we will present new statistical evidence that certain project parameters promote the occurrence of communication gaps more than others. Second, we show that the collected data supports meaningful correlations among individual communication gaps. Third, we demonstrate interesting dependencies between project characteristics and possible effects of communication gaps, such as, not meeting the project budget or deadlines.

These days, it is impossible to imagine a world without smartphones and their multifaceted applications. Yet, many of these mobile applications suffer from various shortcomings end-users observe. In order to give these users a medium to submit feedback, we investigate in this master thesis a feedback elicitation process for mobile applications. For this purpose, we developed a mobile feedback system consisting of a mobile application called AppEcho, a feedback database and additional utilities. We demonstrate how an easy and intuitive feedback elicitation process on smartphones may look like. From a technical point of view, we show how AppEcho keeps track of the applications that are currently running on the smartphone and how it automatically creates screenshots. Our first evaluation of the resulting feedback shows that such a process as well as such a system is feasible. With this thesis, we gain first insights into gathering feedback for mobile applications.

Mobile platforms and applications are an exciting and important phenomenon in today's software and business world. They are being woven into the fabric of daily life faster than expected. Continuous collection of user feedback enabling the improvement of platforms and applications becomes critical to support the continuous evolution of mobile systems. Particularly user feed- back is needed to provide systems that best fit user needs. We have designed a mobile feedback approach, which enables users to document individual feedback on mobile systems in situ. This information can then be evaluated and used as new requirements by developers. Based on this solution we have developed a feed- back app for two different mobile platforms. Furthermore, we have conducted a study with smartphone users applying this ap- proach and communicating feedback on a mobile platform and pre-installed apps. The study revealed that users were able to give individual feedback and that a large amount of this feedback was considered to be useful for mobile system improvement by a platform developer.

In software and requirements engineering, requirements elicitation is considered an essential step towards building successful systems. Despite extensive existing research in the field of distributed requirements engineering, the topic of requirements elicitation for cloud systems remains still uncovered. Cloud challenges (e.g., heterogeneous and globally distributed users, volatile requirements, frequent change requests) cannot always be satisfied by existing methods. We present a new approach for eliciting requirements for cloud services by analyzing advanced search queries. Our approach builds fuzzy Galois lattices for the terms that compose advanced search queries, thus enabling a thorough analysis of stored search data. This can support cloud providers in observing requirements clusters and new classes of cloud services, identifying the threshold for achieving satisfied consumers with a minimal set of requirements implemented, and thus designing novel solutions, based on market trends. Moreover, the Galois lattices approach enables large-scale consumers’ involvement and ensures the elicitation of real requirements unobtrusively.

In this thesis we investigated the contexts in which end users elicit requirements. We have conducted an overview of the state-of-the-art research on end-user involvement in requirements engineering. We proposed that there are three distinct contexts that have to be taken into account - the documentation, the triggering and the future system context. For our analysis, we performed case studies in which students are given two end-user requirements elicitation tools and we analyze when and in what circumstances end-user needs are triggered and recorded. The results we compiled indicate that we can distinguish the three contexts. This leads to a better understanding of end-user requirements elicitation and can help us build better elicitation tools.

This glossary aims at collecting the existing knowledge on Requirements Engineering terminology and defining the core terminology carefully and consistently. In cases where more than one definition is in use or where terms are defined differently when viewed from different perspectives, multiple definitions or perspectives are included. For terms having both a general meaning and a specific meaning in a Requirements Engineering context, both meanings are defined. Important terms are annotated with hints and additional information.

Abstract. Introducing a product line approach in an organization requires a systematic scoping phase to decide what products and features should be included. Product line scoping is a non-trivial activity and traditionally consumes a lot of time and resources. This issue highlights the need to complement traditional scoping activities with semi-automatic approaches that allow to initially estimate the potential for reuse with small efforts. In this paper we present an evaluation of a tool-supported approach that enables the semi-automatic analysis of existing products in order to calculate their similarity. This approach is tailored to be used within the configuration-based systems domain, where we have used it to identify similarity within two types of industrial standard software products. The results of this evaluation highlight that our approach provides accurate results and leads to time savings compared to manual similarity analysis.

With the increase in complexity of modern software systems, the complexity of models and sketches of these systems increases too. This thesis describes a concept for interlinking of and navigation between sketches with FlexiSketch on different abstraction levels. Based on the difficulties presented by the increasing complexity of diagrams and sketches a user-friendly solution for the creation of relations between sketches and objects within sketches is designed. In addition to the interlinking of sketches, a navigation feature that includes a graphical representation of relations between these sketches is presented. Furthermore, additional features for the future development of FlexiSketch are proposed.

Software development is a process that requires great abilities in creative thinking. Especially in early stages of software requirement elicitation when it comes to software design, creativity plays an essential role. Software design is an activity that is often performed in group meetings attended by various stakeholders of the software development project. The goal of having multiple people thinking out of the box leverages the number of creative ideas they produce. In order to communicate, refine, combine, and document their ideas, participants of such meetings use to sketch. FlexiSketch is an existing Android tablet application that increases the productivity of sketching in early phases of software engineering. With FlexiSketch, individuals are able to draw naturally informal sketches and lightweight models. However, FlexiSketch has shown that it has a lack of collaboration. To overcome this issue, we propose a more sophisticated and maintainable prototype solution of FlexiSketch to meet the practices of collaborative software design meetings. Moreover, we present the results and findings of an evaluation of our solution, which lead to suggestions for future work.

Traditionally, metamodeling is an upfront activity performed by experts for defining modeling languages. Modeling tools then typically restrict modelers to using only constructs defined in the metamodel. This is inappropriate when users want to sketch graphical models without any restrictions and only later assign meanings to the sketched elements. Upfront metamodeling also complicates the creation of domain-specific languages, as it requires experts with both domain and metamodeling expertise. In this paper we present a new approach that supports modelers in creating metamodels for diagrams they have sketched or are currently sketching. Metamodels are defined in a semi-automatic, interactive way by annotating diagram elements and automated model analysis. Our approach requires no metamodeling expertise and supports the co-evolution of models and meta-models.

The emerging cloud computing posses various challenges on the development of software systems. In the Requirements Engineering field significant gaps have been identified with respect to the requirements elicitation activity. These result mostly from the lack of appropriate elicitation techniques in the context of the heterogeneous and globally distributed cloud service customers. Moreover, given the complex needs of the users and the increasing number of available cloud products, solutions are required to support the users to identify the services that best match their requirements. A community platform, named StakeCloud, has been proposed to address these issues. It is conceptualized to serve both cloud service users and providers by enabling the first to search for their desired products and providing the latter with relevant user requirements. This thesis proposes a design and an implementation of the StakeCloud interface intended for cloud service customers. It demonstrates a self-adapting and data-driven behavior that serves the purposes of the StakeCloud concept. As it was recognized that the system should be eligible for intense modifications and expansions, due to the young age of the cloud environment, flexibility and maintainability were the guiding principles for the realization of the project.