Andreas Seibel

The role of models and megamodels at runtime

In model-driven software development a multitude of interrelated models are used to systematically realize a software system. This results in a complex development process since the models and the relations between the models have to be managed. Similar problems appear when following a model-driven approach for managing software systems at runtime. A multitude of interrelated runtime models are employed simultaneously, and thus they have to be maintained at runtime. While for the development case megamodels have emerged to address the problem of managing models and relations, the problem is rather neglected for the case of runtime models by applying ad-hoc solutions. Therefore, we propose to utilize megamodel concepts for the case of multiple runtimemodels. Based on the current state of research, we present a categorization of runtimemodels and conceivable relations between them. The categorization describes the role of interrelated models at runtime and demonstrates that several approaches already employ multiple runtime models and relations. Then, we show how megamodel concepts help in organizing and utilizing runtime models and relations in amodel-driven manner while supporting a high level of automation. Finally, the role of interrelated models and megamodels at runtime is discussed for self-adaptive software systems and exemplified by a case study.

Dynamic hierarchical mega models: comprehensive traceability and its efficient maintenance

In the world of model-driven engineering (MDE) support for traceability and maintenance of traceability information is essential. On the one hand, classical traceability approaches for MDE address this need by supporting automated creation of traceability information on the model element level. On the other hand, global model management approaches manually capture traceability information on the model level. However, there is currently no approach that supports comprehensive traceability, comprising traceability information on both levels, and efficient maintenance of traceability information, which requires a high-degree of automation and scalability. In this article, we present a comprehensive traceability approach that combines classical traceability approaches for MDE and global model management in form of dynamic hierarchical mega models. We further integrate efficient maintenance of traceability information based on top of dynamic hierarchical mega models. The proposed approach is further outlined by using an industrial case study and by presenting an implementation of the concepts in form of a prototype.

Teaching requirements engineering with virtual stakeholders without software engineering knowledge

Teaching requirements engineering (RE) is a difficult endeavor since it must reflect the reality as close as possible. Also, a sense of risk for the students should be included, while the supervisors need to be in control all the time. Related literature agrees on the importance of stakeholders for RE education.

On the Complex Nature of MDE Evolution

In Model-Driven Engineering MDE the employed setting of languages as well as automated and manual activities has major impact on productivity. Furthermore, such settings for MDE evolve over time. However, currently only the evolution of modeling languages, tools, and transformations is studied in research. It is not clear whether these are the only relevant changes that characterize MDE evolution in practice. In this paper we address this lack of knowledge. We first discuss possible changes and then report on a first study that demonstrates that these forms of evolution can be commonly observed in practice. To investigate the complex nature of MDE evolution in more depth, we captured the evolution of three MDE settings from practice and derive eight observations concerning reasons for MDE evolution. Based on the observations we then identify open research challenge concerning MDE evolution.

Interactive Visualization for Elicitation and Validationn of Requirements with Scenario-Based Prototyping

The different perspectives stakeholders and requirements engineers have on a problem are a major hindrance to de- rive useful requirements. While formal requirements mod- els are well suited for excluding inconsistent requirements, prototypes presented to stakeholders are very effective to ensure valid requirements. In this position paper we report about our vision to combine both approaches in form of scenario-based prototyping, which enables the interactive visualization for elicitation and validation of requirements for systems with multiple users in the business domain.

Towards Next Generation Design Thinking: Scenario-Based Prototyping for Designing Complex Software Systems with Multiple Users

Design thinking is at its best if tangible prototypes can be used to capture and validate end user needs and envision new products and services. However, today such tangible prototypes are not feasible in a cost-effective manner for complex software systems with multiple users and their complex behavior. To overcome this problem, we developed a scenario-based prototyping approach for complex multi-user software systems that uses executable software engineering models including structural as well as behavioral aspects. Simulation turns these models into tangible virtual prototypes for end users that visualize the complex behavior and capture feedback interactively. In this chapter, we elaborate our concept for cost-effective scenario-based prototyping, report on a first prototypical implementation of the approach for the validation of multi-user processes with end users, and discuss our initial findings and learnings that we gained from first experiments with the implementation.

Why should I help you to teach requirements engineering

To teach requirements engineering skills to students it is important for them to experience stakeholder interactions in a realistic setting. Only then they learn to appreciate the effort it takes to elicit, document, and validate requirements. For a realistic course design, all stakeholders the students interact with need to be real, thus, they need to have a stake in the software system being specified. In this paper, we discuss plausible motivations of real stakeholders. As long as stakeholders benefit in a way that suits them, they are readily available to get involved, even with students just learning how to capture requirements. Also, we discuss two ongoing case studies of involving real stakeholders in a requirements engineering course. While these setups do not scale well, they provide the students an authentic situation which cannot be reproduced with virtual stakeholders.

A dedicated language for context composition and execution of true black-box model transformations

Model-Driven Engineering (MDE) automates development activities by employing model transformations. Thereby, a plethora of model transformation approaches with individual capabilities have been developed. In certain cases, complex and automated MDE activities require the interaction of various, potentially heterogeneous, model transformations. This can be achieved by a loosely coupled and highly cohesive composition of model transformations implemented in different model transformation languages. However, existing approaches either do not support context composition, using other model transformations as additional context, or they violate the important black-box principle because they require adapting model transformations for context composition. In this paper, we present a dedicated model transformation composition framework (MoTCoF) that does not require the adaptation of model transformations and, thus, treats model transformations as true black-boxes. We illustrate our approach with an application example taken from an industrial case study.

From Software Traceability to Global Model Management and Back Again

In the past, traceability was concerned with tracing requirements also known as requirements traceability. Meanwhile, model-driven engineering (MDE) becomes popular and in this context, requirements traceability evolved to a more general software traceability, which is about tracing any relationship between software artifacts. Due to increasing heterogeneity and complexity of MDE, global model management (GMM) becomes indispensable to MDE. In state-of-the-art GMM approaches, traceability is primarily concerned with tracing model transformations, which generate traceability information as side-effect. However, this is only a subset of the capabilities of software traceability. My hypothesis is that GMM can benefit from software traceability by applying software traceability techniques into the context of GMM. Thus, I will consider GMM from a traceability perspective and show new possibilities to GMM that arise from taking in this perspective.

Navigating Across Non-Navigable Ecore References via OCL

The Eclipse Modeling Framework (EMF) and its meta-meta model Ecore support uni-directional and bi-directional references. It is quite common that references are defined uni-directionally only because of saving storage space or separating meta models, which is problematic when implementing Object Constraint Language (OCL) constraints that require navigation against the direction of uni-directional references. This is essential for certain approaches, e.g., incremental evaluation of OCL constraints on models shown by Altenhofen et al. that is used in SAPs Modeling Infrastructure (MOIN). In this paper, we present an approach that overcomes the aforementioned issue by providing navigation across non-navigable Ecore references via OCL. We further discuss different alternative solutions and briefly describe the realization that was outcome of a project in cooperation with the SAP AG.