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Auflistung nach Autor:in "Keller, Robert"

1 - 9 von 9
  • Zeitschriftenartikel
    Analyse von Risikomanagementstrategien in Cloudnetzwerken – Was tun bei verknüpften, voneinander abhängigen Cloud Services?
    (HMD Praxis der Wirtschaftsinformatik: Vol. 53, No. 5, 2016) Keller, Robert
    Cloud Services nutzen zunehmend andere Cloud Services zur Leistungserstellung. Dies führt zu einer immer stärkeren Vernetzung und komplexen Abhängigkeitsstrukturen, in denen Risiken zwischen den Anbietern übertragen werden können. Vor diesem Hintergrund soll sowohl strukturiert als auch anhand von Beispielen aufgezeigt werden, welche Rollen Unternehmen in Cloudnetzwerken einnehmen und welche Risiken auf sie wirken können. Um den aufgezeigten, netzwerkspezifischen Risiken begegnen zu können, gibt es in anderen Branchen, wie z. B. dem Supply Chain Management oder der Finanzbranche, bereits verschiedene Risikomanagementstrategien. Es soll eine Abschätzung darüber abgegeben werden, in wieweit sich diese und bekannte IT-spezifische Risikomanagementstrategien zur Adressierung der Risiken in Cloudnetzwerken eignen. Abschließend sollen konkrete Maßnahmen zur Anwendung in Unternehmen abgeleitet werden.AbstractCloud providers increasingly use other cloud services to provide services to their customers. Consequently, this rising interconnection leads to complex dependencies between actors in cloud computing that disseminate risks from one to others. With that in mind, this article illustrates the role of companies and risks in cloud networks and their interaction. In order to counteract the described risks, the author examines various risk management strategies of other disciplines, such as supply chain management or the financial industries, whether they are applicable to cloud networks. Finally, the article describes specific actions towards the application of a cloud network risk management.
  • Zeitschriftenartikel
    Ein Blick auf aktuelle Entwicklungen bei Blockchains und deren Auswirkungen auf den Energieverbrauch
    (Informatik Spektrum: Vol. 43, No. 6, 2020) Sedlmeir, Johannes; Buhl, Hans Ulrich; Fridgen, Gilbert; Keller, Robert
    Der enorme Stromverbrauch von Bitcoin hat dazu geführt, dass in Wissenschaft und Praxis oft eher undifferenziert Diskussionen über die Nachhaltigkeit von Blockchain- bzw. Distributed-Ledger-Technologie allgemein geführt werden. Allerdings ist die Blockchain-Technologie bereits heute alles andere als homogen – nicht nur hinsichtlich ihrer Anwendungen, die mittlerweile weit über Kryptowährungen hinaus in Wirtschaft und öffentlichen Sektor reichen, sondern auch bezüglich ihrer technischen Charakteristika und insbesondere ihres Stromverbrauchs. Dieser Beitrag fasst den Status quo des Stromverbrauchs verschiedener Implementierungen von Blockchain-Technologie zusammen und geht dabei besonders auf das kürzlich erfolgte Bitcoin Halving sowie sogenannte ZK-Rollups ein. Wir argumentieren, dass Bitcoin und andere Proof-of-Work-Blockchains zwar in der Tat sehr viel Strom verbrauchen, aber bereits heute alternative Blockchain-Lösungen mit deutlich geringerem Stromverbrauch verfügbar sind und weitere vielversprechende Konzepte erprobt werden, die gerade den Stromverbrauch von großen Blockchain-Netzwerken in naher Zukunft noch einmal deutlich senken könnten. Daraus schließen wir, dass die Kritik am Stromverbrauch von Bitcoin zwar legitim ist, jedoch daraus nicht eine Energieproblematik von Blockchain-Technologie generell abgeleitet werden darf. In vielen Fällen, in denen mithilfe von energieeffizienteren Blockchain-Varianten Prozesse digitalisiert oder verbessert werden können, darf sogar per Saldo durchaus mit Energieeinsparungen gerechnet werden. The enormous power consumption of Bitcoin has led to undifferentiated discussions in science and practice about the sustainability of blockchain and distributed ledger technology in general. However, blockchain technology is far from homogeneous—not only with regard to its applications, which now go far beyond cryptocurrencies and have reached businesses and the public sector, but also with regard to its technical characteristics and, in particular, its power consumption. This paper summarizes the status quo of the power consumption of various implementations of blockchain technology, with special emphasis on the recent ‘‘Bitcoin Halving’’ and so-called ‘‘zk-rollups’’. We argue that although Bitcoin and other proof-of-work blockchains do indeed consume a lot of power, alternative blockchain solutions with significantly lower power consumption are already available today, and new promising concepts are being tested that could further reduce in particulary the power consumption of large blockchain networks in the near future. From this we conclude that although the criticism of Bitcoin’s power consumption is legitimate, it should not be used to derive an energy problem of blockchain technology in general. In many cases in which processes can be digitized or improved with the help of more energy-efficient blockchain variants, one can even expect net energy savings.
  • Zeitschriftenartikel
    Flexible IT platform for synchronizing energy demands with volatile markets
    (it - Information Technology: Vol. 60, No. 3, 2018) Schott, Paul; Ahrens, Raphael; Bauer, Dennis; Hering, Fabian; Keller, Robert; Pullmann, Jaroslav; Schel, Daniel; Schimmelpfennig, Jens; Simon, Peter; Weber, Thomas; Abele, Eberhard; Bauernhansl, Thomas; Fridgen, Gilbert; Jarke, Matthias; Reinhart, Gunther
    Abandoning fossil and nuclear energy sources in the long run and increasing amount of renewable energies in electricity production causes a more volatile power supply. Depending on external realities, renewable energy production emphasizes the need for measures to guarantee the necessary balance of demand and supply in the electricity system at all times. Energy intensive industry processes theoretically include high Demand Response potentials suitable to tackle this increasing supply volatility. Nevertheless, most companies do not operate their production in a flexible manner due to multiple reasons: among others, the companies lack know-how, technologies and a clear business case to introduce an additional level of flexibility into their production processes, they are concerned about possible impacts on their processes by varying the electricity demand and need assistance in exploiting their flexibility. Aside from fostering knowledge in industry companies, an IT-solution that supports companies to use their processes’ Demand Response potential has become necessary. Its concept must support companies in managing companies’ energy-flexible production processes and monetarize those potentials at flexibility markets. This paper presents a concept, which integrates both companies and energy markets. It enables automated trading of companies’ Demand Response potential on different flexibility markets.
  • Zeitschriftenartikel
    Pathways to Developing Digital Capabilities within Entrepreneurial Initiatives in Pre-Digital Organizations
    (Business & Information Systems Engineering: Vol. 64, No. 1, 2022) Keller, Robert; Ollig, Philipp; Rövekamp, Patrick
    To enable new digital business models, pre-digital organizations launch entrepreneurial initiatives. However, in developing the required digital capabilities, pre-digital organizations often face challenges as they are marked by the ways they have historically established their organizational identity. Research on how pre-digital organizations can develop digital capabilities remains scarce. This study draws on a single case study to illustrate potential pathways for the development of digital capabilities. Two key characteristics are identified: the source of digital capability development and the set-up of the actors involved. The authors synthesize four possible pathway manifestations, discuss the dynamic nature of pathway combinations, and suggest that managing a portfolio of pathways may be crucial for pre-digital organizations. Therefore, the study contributes to a better understanding of digital transformation in pre-digital organizations. Furthermore, it provides guidance for practitioners to reflect on when deciding which pathways to follow.
  • Zeitschriftenartikel
    Scheduling Flexible Demand in Cloud Computing Spot Markets
    (Business & Information Systems Engineering: Vol. 62, No. 1, 2020) Keller, Robert; H‰fner, Lukas; Sachs, Thomas; Fridgen, Gilbert
    The rapid standardization and specialization of cloud computing services have led to the development of cloud spot markets on which cloud service providers and customers can trade in near real-time. Frequent changes in demand and supply give rise to spot prices that vary throughout the day. Cloud customers often have temporal flexibility to execute their jobs before a specific deadline. In this paper, the authors apply real options analysis (ROA), which is an established valuation method designed to capture the flexibility of action under uncertainty. They adapt and compare multiple discrete-time approaches that enable cloud customers to quantify and exploit the monetary value of their short-term temporal flexibility. The paper contributes to the field by guaranteeing cloud job execution of variable-time requests in a single cloud spot market, whereas existing multi-market strategies may not fulfill requests when outbid. In a broad simulation of scenarios for the use of Amazon EC2 spot instances, the developed approaches exploit the existing savings potential up to 40 percent - a considerable extent. Moreover, the results demonstrate that ROA, which explicitly considers time-of-day-specific spot price patterns, outperforms traditional option pricing models and expectation optimization.
  • Konferenzbeitrag
    Sustainable ecosystems: Findings from the NaWerSys workshop series
    (INFORMATIK 2024, 2024) Schoormann, Thorsten; Kammler, Friedemann; Gembarski, Paul Christoph; Hagen, Simon; Brinker, Jonas; Bollenbach, Jessica; Jussen, Ilka; Keller, Robert; Kortum-Landwehr, Henrik; Möller, Frederik; Petrik, Dimitri; Schweihoff, Julia; Stachon, Maleen; Winkelmann, Stephanie
    Ecosystems have the promising potential to respond to economic but also environmental and social challenges, such as by enabling circular thinking, establishing fair supply chains, responsible collaborations, and ensuring resilience. In this report, we summarize findings from multiple data sources in the context of the NaWerSys workshop series which was held together with the INFORMATIK conference. The results are informed by experiences collected from full-day paper sessions in 2021, 2022, and 2023, and a world café-based discussion with 15 participants from different backgrounds, including sustainability, engineering, platform governance, product service systems, and artificial intelligence. We structured the results along with four main fields of action concerning the core, the value, the design, and the management of sustainable ecosystems. By jointly elaborating on the status quo and possible research directions, the findings aim to advance our understanding and boost the concept of sustainable ecosystems.
  • Zeitschriftenartikel
    The Design of Citizen-Centric Green IS in Sustainable Smart Districts
    (Business & Information Systems Engineering: Vol. 65, No. 5, 2023) Graf-Drasch, Valerie; Keller, Robert; Meindl, Oliver; Röhrich, Felix
    Green information systems are often praised for their potential to foster sustainability in citizens’ daily lives and meet their needs. With this focus on citizens, districts that use smart technologies provide a litmus test, the results of which will indicate how to design smart green information systems that better meet the needs and desires of citizens. To date, however, guidelines on how to design such green information systems in urban areas or actively involve citizens in this process are few and far between. In recognition and remedy of this shortage, the study draws on the design science research paradigm to develop seven design principles for citizen-centric green information systems that can be used in sustainable smart districts. These principles are evaluated in 15 semi-structured interviews and a prototype of a mobile district app for a citizen-centric green information system is instantiated. By taking this citizen-centric perspective, the paper fosters the active involvement of humans in the design of sustainable urban environments.
  • Zeitschriftenartikel
    The Energy Consumption of Blockchain Technology: Beyond Myth
    (Business & Information Systems Engineering: Vol. 62, No. 6, 2020) Sedlmeir, Johannes; Buhl, Hans Ulrich; Fridgen, Gilbert; Keller, Robert
    When talking about blockchain technology in academia, business, and society, frequently generalizations are still heared about its – supposedly inherent – enormous energy consumption. This perception inevitably raises concerns about the further adoption of blockchain technology, a fact that inhibits rapid uptake of what is widely considered to be a groundbreaking and disruptive innovation. However, blockchain technology is far from homogeneous, meaning that blanket statements about its energy consumption should be reviewed with care. The article is meant to bring clarity to the topic in a holistic fashion, looking beyond claims regarding the energy consumption of Bitcoin, which have, so far, dominated the discussion.
  • Konferenzbeitrag
    To Graph or Not to Graph: The Missing Pieces for Knowledge Graphs in Sustainable Tourism
    (INFORMATIK 2023 - Designing Futures: Zukünfte gestalten, 2023) Neubig, Stefan; Rebholz, Dominik; Hein, Andreas; Keller, Robert; Krcmar, Helmut
    Sustainability is a critical challenge in modern tourism, exacerbated by climate change and globalization. Thanks to digitization, data-driven approaches constitute a key technology for addressing related issues, such as overtourism. However, the overarching complexity of the touristic data landscape, amplified by the interplay of diverse digital platform ecosystems, poses considerable challenges to both data owners and consumers. To mitigate such issues, knowledge graphs (KGs) have received significant attention. KGs focus on data quality by employing unified data models and continuous data refinements, making them well-suited for data-driven applications. Although promising, many challenges must be addressed to make KGs useful in practice. This paper overviews the state of the art of the field and identifies avenues for future research, explicitly focusing on touristic value and sustainability. Following our results, future research should focus on different areas, notably real-time knowledge graph population, distributed and parallelized processes, and ontologies for dynamic data types.