Marian Daun

Detecting and Correcting Outdated Requirements in Function-Centered Engineering of Embedded Systems

[Context and Motivation] In function-centered engineering of embedded systems, changes of stakeholder intentions are often directly incorporated in the functional design without updating the behavioral requirements accordingly. [Question/Problem] As a consequence, it is likely that the behavioral requirements of the system become outdated over the course of the engineering process. [Principal Ideas/Results] We propose a validation technique that aids the requirements engineer in detecting and correcting outdated behavioral requirements. The approach relies on a dedicated review model that represents a consolidated view of behavioral requirements and functional design. [Contributions] This paper reports on a semi-automated approach and presents first experimental results showing that our technique can significantly aid the requirements engineer in the detection and correction of outdated behavioral requirements.

The impact of students' skills and experiences on empirical results: a controlled experiment with undergraduate and graduate students

In empirical software engineering research, graduate students are often seen as legitimate substitutes for industry professionals. It has been also argued in the literature that the generalizability of empirical results from experiments with undergraduate students as participants holds to a much lower extent. In this paper, we report on a controlled experiment conducted separately with graduate students and undergraduate students in order to gain deeper insights whether the results from experiments with graduates and undergraduates in the software engineering field are equal or significantly different with respect to the conclusions that can be drawn. During the experiment, the students apply a specific validation technique for behavioral requirements of embedded software. We observed that graduates were significantly more effective, efficient, and confident in their tasks than the undergraduates. Nevertheless, the experiment with undergraduates also shows significant results, even though with a smaller effect size.

Validating the functional design of embedded systems against stakeholder intentions

In the embedded systems industry, function-centered engineering is commonly applied to address the increasing number and complexity of system functions. During function-centered engineering, the functional design that is created based on the defined requirements for the system is the main artifact that serves as a basis for subsequent development activities. If stakeholder intentions change and modifications become necessary, they are frequently incorporated directly into the functional design without updating the behavioral requirements accordingly. As a consequence, the correctness of the interplay of system functions as defined in the functional design cannot be assessed by checking it against the defined requirements (since they are outdated) but needs to be checked against the current stakeholder intentions. More precisely, the requirements engineer has to validate the functional design against the stakeholder intentions because he is the expert concerning the stakeholder intentions and can communicate with the stakeholders regarding them, if necessary. However, the requirements engineer is typically not familiar with the functional design and its notation on the one hand, and, on the other hand, the overall behavior of the system is spread across various diagrams in the functional design. Therefore, the requirements engineer needs a more abstract and consolidated view of the functional design in order to be able to validate its correctness with regard to the current stakeholder intentions. In this paper, we present an approach which is based on a specific kind of review model that is automatically generated from the functional design and supports the requirements engineer in her task. The approach that is presented in this paper is subject of ongoing research.

Supporting the Consistent Specification of Scenarios across Multiple Abstraction Levels

[Context and motivation] In scenario-based requirements engineering for complex software-intensive systems, scenarios must be specified and kept consistent across several levels of abstraction such as system and component level. [Question/problem] Existing scenario-based approaches do not provide a systematic support for the transitions between different abstraction levels such as defining component scenarios based on the system scenarios and the system architecture or checking whether the component scenarios are consistent with the system scenarios. [Principal ideas/results] This paper presents a systematic approach for developing scenarios at multiple abstraction levels supported by automated consistency checks of scenarios across these abstraction levels. [Contribution] We have implemented the consistency check in a tool prototype and evaluated our approach by applying it to a (simplified) adaptive cruise control (ACC) system.

Common Threats and Mitigation Strategies in Requirements Engineering Experiments with Student Participants

[Context and motivation] Experiments are an important means to evaluate research results in the field of requirements engineering. Researchers often conduct such experiments with student participants. [Question/problem] The use of student participants evokes a multitude of potential threats to validity, which must be properly addressed by the chosen experiment design. In practice, attention is mostly given to threats to the generalizability of the findings. However, current experiment reports often lack a proper discussion of further threats, for example, which are caused by the recruitment of student participants. [Principle ideas/results] To provide mitigation strategies for student specific threats to validity, these threats must be known. We analyzed student experiments from published experiment reports to identify student specific threats and to analyze adequate mitigation strategies. [Contribution] This paper contributes a detailed analysis of the threats to validity to be considered in student experiments, and possible mitigation strategies to avoid these threats. In addition, we report on an experiment conducted in a university requirements engineering course, where we considered student specific threats and applied the proposed mitigation strategies.

Modeling Quality Aspects: Real-Time

The meaning of real-time computing is overloaded and ambiguous. Often it is associated with a quick and immediate system response to an external event or it is used to describe the performance of multimedia systems that achieve more than 25 frames per second.

On the Impact of the Model-Based Representation of Inconsistencies to Manual Reviews

To ensure fulfilling stakeholder wishes, it is crucial to validate the documented requirements. This is often complicated by the fact that the wishes and intentions of different stakeholders are somewhat contradictory, which manifests itself in inconsistent requirements. To aid requirements engineers in identifying and resolving inconsistent requirements, we investigated the usefulness for manual reviews of two different model-based representation formats for inconsistent requirements; one that represent the inconsistent requirements in separate diagrams and one that represents them integrated into one diagram using annotations. The results from a controlled experiment show that the use of such integrated review diagrams can significantly increase efficiency of manual reviews, without sacrificing effectiveness.

An Ontological Context Modeling Framework for Coping with the Dynamic Contexts of Cyber-physical Systems.

Cyber-physical systems are highly collaborative by nature. At runtime these systems collaborate with each other to achieve goals that a single system could not achieve on its own. For example, autonomous vehicles can dynamically form convoys at runtime to facilitate higher traffic throughput and a reduction in CO2 emissions. While the importance of context documentation and analysis in system development is well known, current model-based engineering approaches struggle with the size and complexity of cyber-physical systems’ contexts. This is due to high variety and dynamicity of the contexts to be considered. For example, a convoy to be formed at runtime may consist of different numbers of participating vehicles. Additionally, it may face different neighboring, not partaking context systems (e.g., non-equipped vehicles, equipped but not participating vehicles) and situations (e.g., speed limits, road construction sites, emergency vehicles). This paper proposes a context ontology to cope with highly dynamic contexts of cyber-physical systems by explicitly differentiating between not only the system and its context but also between the cyber-physical system network the system participates in, as well as the system network’s context.

On Different Search Methods for Systematic Literature Reviews and Maps: Experiences from a Literature Search on Validation and Verification of Emergent Behavior

[Background] Systematic literature reviews and maps have become well-established research methods in software engineering research. Of the three commonly suggested and used search methods: manual search, database search, or snowball search; systematic literature reviews and maps typically employ one or a combination of two or three of those as their search strategy. As systematic literature reviews and maps raise a claim to result in a representative set of relevant papers for a certain area of investigation, it is of importance to understand the impact the search strategy has on achieving this goal. [Aim] This paper contributes a study to compare all three search methods. This study aims at providing evidence as to what advantages and disadvantages of these three search methods are. [Method] We conducted three systematic literature reviews on the same topic, which affects multiple software engineering related disciplines, using different search methods, while keeping other parameters like inclusion and exclusion criteria consistent among all three reviews. [Results] Our results show a similar effectiveness for snowball and database search and the highest efficiency for database searches. However, our literature reviews led to three barely overlapping sets of papers, which in turn led to distinct impressions of the same field. [Conclusion] Our results show that the use of a single search method can lead to a set of included papers, which misrepresents the research field under investigation. Hence, particularly when conducting literature reviews that affect different software engineering sub-disciplines and related disciplines, researchers should not just rely on the single most effective and/or efficient search method.

Approaches, success factors, and barriers for technology transfer in software engineering-Results of a systematic literature review

Technology transfer aims at supporting the transfer of results from software engineering research from academia to industrial application.