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PublicationAirport capacity extension, fleet investment, and optimal aircraft scheduling in a multilevel market model: Quantifying the costs of imperfect markets( 2021)We present a market model of a liberalized aviation market with independent decision makers. The model consists of a hierarchical, trilevel optimization problem where perfectly competitive budget-constrained airports decide (in the first level) on optimal runway capacity extensions and airport charges by anticipating long-term fleet investment and medium-term aircraft scheduling decisions taken by a set of imperfectly competitive airlines (in the second level). Both airports and airlines anticipate the short-term outcome of a perfectly competitive ticket market (in the third level). We compare our trilevel model to an integrated single-level (benchmark) model in which investments, scheduling, and market-clearing decisions are simultaneously taken by a welfare-maximizing social planner. Using a simple six airports example from the literature, we illustrate the inefficiency of long-run investments in both runway capacity and aircraft fleet which may be observed in aviation markets with imperfectly competitive airlines.
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PublicationGAIA-X and IDS(International Data Spaces Association, 2021)
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PublicationOrganizing Self-Organizing Systems: A Terminology, Taxonomy, and Reference Model for Entities in Cyber-physical Production Systems( 2021)Ongoing digitalization accelerates the transformation and integration of physical production and traditional computing systems into smart objects and their interconnectivity, forming the Internet of Things. In manufacturing, the cross-linking of embedded systems creates adaptive and self-organizing Cyber-Physical Production Systems (CPPSs). Owing to ever-increasing cross-linking, rapid technological advances, and multifunctionality, the complexity and structural opacity of CPPSs are rapidly increasing. The development of urgently needed modeling approaches for managing such complexity and structural opacity, however, is impeded by a lack of common understanding of CPPSs. Therefore, in this paper, we contribute to a common understanding of CPPSs by defining and classifying CPPS entities and illustrating their relations. More precisely, we present a terminology, a taxonomy, and a reference model for CPPS entities, created and evaluated using an iterative development process. Thereby, we lay the foundation for future CPPS modeling approaches that make CPPS complexity and structural opacity more manageable.
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PublicationBlockchain for Education: Lifelong Learning Passport( 2018)Certificates play an important role in education and in professional development in companies. Individual learning records become essential for people's professional careers. It is therefore important that these records are stored in long-term available and tamper-proof ledgers. A blockchain records transactions in a verifiable and permanent way, therefore it is very suitable to store fingerprints of certificates or other educational items. Blockchain reveals forgery of certificates and it supports learning histories. In this paper, we present the Blockchain for Education platform as a practical solution for issuing, validating and sharing of certificates. At first, we describe the conceptual system overview and then we present in detail the platform implementation including management of certification authorities and certificates, smart contracts as well as services for certifiers, learners and third parties such as employers. Finally, we describe use cases and first evaluation results that we gathered from end user tests with certifiers and conclude with a discussion.
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PublicationBlockchain and smart contracts(Fraunhofer-Gesellschaft, 2018)This position paper analyzes blockchain technology from the scientific and application-oriented perspective of the Fraunhofer-Gesellschaft. It examines relevant technical aspects and related research questions. It shows that technology still has fundamental research and development challenges in all areas. These include, for example, the modularization of individual blockchain concepts as well as their combination and integration for application-specific blockchain solutions.
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PublicationIDS Reference Architecture Model. Industrial Data Space. Version 2.0(International Data Spaces Association, 2018)
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PublicationDesign it like Darwin - A value-based application of evolutionary algorithms for proper and unambiguous business process redesign( 2017)Business process management (BPM) is an acknowledged source of corporate performance. Despite the mature body of knowledge, computational support is considered as a highly relevant research gap for redesigning business processes. Therefore, this paper applies Evolutionary Algorithms (EAs) that, on a conceptual level, mimic the BPM lifecycle - the most popular BPM approach - by incrementally improving the status quo and bridging the trade-off between maintaining well-performing design structures and continuously evolving new designs. Beginning with describing process elements and their characteristics in matrices to aggregate process information, the EA then processes this information and combines the elements to new designs. These designs are then assessed by a function from value-base d management. This economic paradigm reduces designs to their value contributions and facilitates an objective prioritization. Altogether, our triad of management science, BPM and information systems research results in a promising tool for process redesign and avoids subjective vagueness inherent to current redesign projects.
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PublicationThe Sustainability Imperative in Information Systems Research( 2017)This paper reports on a panel discussion at the Pre-ICIS 2015 Workshop on Green Information Sys-tems on the current state and future perspectives of SIGGreen, the special interest group of the Association of Information Systems on green information systems. SIGGreen recognizes the central role of information systems (IS) in creating an ecologically sustainable society. Over the past years, IS scholars have made important contributions advancing our knowledge about how information systems can contribute to solving problems associated with the degradation of the natural envi-ronment. Still, it seems that green IS is, by and large, viewed as just another research branch in IS. We put forward the proposition that, to meet our social responsibility, green IS must not be treated as yet another IS research area. The problem addressed by green IS is simply too big. While, for instance, the awareness of the potential of information systems to increase productivity has been in our disciplines DNA for more than five decades, this is clearly not the case for the potential of information systems to achieve a sustainable world. We suggest that the IS community embraces sustainability as a research imperative and integrates sustainability related aspects in research across methods, theories, and areas.
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PublicationTowards an optimal investment strategy considering fashionable IT innovations a dynamic optimization model( 2017)Companies regularly face the challenge of deciding whether, when and to which extent they should invest in IT innovations with different maturity. The IT innovation strategy thereby should consider mature as well as fashionable IT innovations as investment alternatives. As previous researchs focus is rather qualitative, we develop a dynamic optimization model that determines the optimal strategic allocation of an IT innovation budget to mature and fashionable IT innovations. By using a simulation-based approach, we analyze the essential causal relationships between the theoretical optimum and the factors of major influence. We find that companies should invest in fashionable IT innovations even if their own level of innovativeness is rather low and the technologys success probability has not reached a high threshold yet. Our findings provide a basis for further research on mindful investment decisions in fashionable IT innovations.
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PublicationBlockchain und Smart Contracts(Fraunhofer-Gesellschaft, 2017)Dieses Positionspapier analysiert die Blockchain-Technologie aus wissenschaftlicher und anwendungsorientierter Sicht der Fraunhofer-Gesellschaft. Es untersucht relevante Technikaspekte und damit verbundene Forschungsfragen. Dabei zeigt sich, dass die Technik in allen Bereichen noch grundlegende Forschungs- und Entwicklungs-Herausforderungen aufweist. Diese liegen beispielsweise in der Modularisierung einzelner Blockchain-Konzepte sowie deren Kombination und Integration für anwendungsspezifische Blockchain-Lösungen.
