@inproceedings{FritzSchmidMottok, author = {Fritz, Florian and Schmid, Michael and Mottok, J{\"u}rgen}, title = {Accelerating Real-Time Applications with Predictable Work-Stealing}, series = {Architecture of computing systems - ARCS 2020: 33rd international conference, Aachen, Germany, May 25-28, 2020, proceedings}, booktitle = {Architecture of computing systems - ARCS 2020: 33rd international conference, Aachen, Germany, May 25-28, 2020, proceedings}, editor = {Brinkmann, Andr{\´e}}, doi = {10.1007/978-3-030-52794-5_18}, pages = {241 -- 255}, abstract = {Modern compute architectures often consist of multiple CPU cores to achieve their performance, as physical properties put a limit on the execution speed of a single processor. This trend is also visible in the embedded and real-time domain, where programmers are forced to parallelize their software to keep deadlines. Additionally, embedded systems rely increasingly on modular applications, that can easily be adapted to different system loads and hardware configurations. To parallelize applications under these dynamic conditions, often dispatching frameworks like Threading Building Blocks (TBB) are used in the desktop and server segment. More recently, Embedded Multicore Building Blocks (EMB2) was developed as a task-based programming solution designed with the constraints of embedded systems in mind. In this paper, we discuss how task-based programming fits such systems by analyzing scheduler implementation variants, with a focus on classic work-stealing and the libraries TBB and EMB2. Based on the state of the art we introduce a novel resource-trading concept that allows static memory allocation in a work-stealing runtime holding strict space and time bounds. We conduct benchmarks between an early prototype of the concept, TBB and EMB2, showing that resource-trading does not introduce additional runtime overheads, while unfortunately also not improving on execution time variances.}, language = {en} } @inproceedings{SchmidFritzMottok, author = {Schmid, Michael and Fritz, Florian and Mottok, J{\"u}rgen}, title = {Parallel Programming in Real-Time Systems}, series = {Architecture of computing systems - ARCS 2019, 32nd international conference, Copenhagen, Denmark, May 20-21, 2019, proceedings}, booktitle = {Architecture of computing systems - ARCS 2019, 32nd international conference, Copenhagen, Denmark, May 20-21, 2019, proceedings}, publisher = {VDE-Verlag}, address = {Berlin}, abstract = {The enormous amounts of data modern real-time systems have to process lead to expensive, long-lasting calculations. In order to manage those computations in a timely manner, parallel task models have gained a lot of popularity lately. However, parallel programming can be very cumbersome and verbose. Other computationally intensive sectors have dealt with parallel computing for decades and have accumulated their experience in the development of parallel frameworks. Examples of well known parallel runtime systems are OpenMP, Intel Threading Building Blocks (TBB) and Microsoft Parallel Pattern Library (PPL). These runtime systems allow developers to enhance parallelism in their applications in a straightforward fashion. However, those parallel frameworks and the patternbased interfaces they provide might not be easily applicable in real-time systems. In this paper, we investigate the use of parallel programming frameworks in time-critical systems. On that account, we discuss considerations for the design of real-time applications that make use of such parallel runtime systems. Furthermore, we evaluate three library-based frameworks from different computing sectors, namely Intel Threading Building Blocks, Embedded Multicore Building Blocks (EMBB) and High Performance ParalleX (HPX), by conducting benchmarks of various parallel algorithms on an embedded multicore architecture.}, language = {en} } @article{StadlerCornetFrenkler, author = {Stadler, Sebastian and Cornet, Henriette and Frenkler, Fritz}, title = {Towards user acceptance of autonomous vehicles: a virtual reality study on human-machine interfaces}, series = {International Journal of Technology Marketing: : IJTMkt}, volume = {13}, journal = {International Journal of Technology Marketing: : IJTMkt}, number = {3/4}, publisher = {Inderscience Enterprises}, address = {Olney, Bucks}, issn = {1741-8798}, doi = {10.1504/IJTMKT.2019.104601}, pages = {325}, abstract = {Technological advances in businesses related to automated transportation raise challenges. Indeed, ensuring safety for users is essential for the future commercial launch of this technology. Within this study, human-machine interfaces (HMIs) are evaluated regarding the communication between autonomous vehicles (AVs) and pedestrians in order to prepare a successful deployment of the technology on the market. Since real-life experiments involving AVs remain dangerous, experiments were conducted via virtual reality (VR). The results show that beyond the need for HMIs, display-based concepts were more usable than laser projections. The study impacts on: 1) substantiating the need for explicit HMIs on AVs (including concept recommendations) for a successful market entry; 2) proving that VR constitutes an advantageous alternative for conducting experiments in the field of autonomous transportation for both research and business. Further work is needed that involves more participants and an improved virtual environment.}, language = {en} } @inproceedings{FritzSchmidEhrlich, author = {Fritz, B. and Schmid, Vinzent and Ehrlich, Ingo}, title = {Analytical and numerical shear stress analysis of adhesive structural bonded joints under tension load}, series = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, booktitle = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, address = {Aachen}, pages = {266 -- 271}, language = {de} } @article{SchmidFritzMottok, author = {Schmid, Michael and Fritz, Florian and Mottok, J{\"u}rgen}, title = {Fine-Grained Parallel Applications in Real-Time Multiprocessor Systems}, series = {Journal of Systems Architecture}, volume = {124}, journal = {Journal of Systems Architecture}, publisher = {Elsevier}, doi = {10.1016/j.sysarc.2022.102393}, abstract = {Lately, parallel task models have received much attention in the development of real-time multiprocessor systems, as they allow highly compute-intensive tasks to have shorter deadlines which is very much required in modern reactive systems. However, missing modularity and portability can make parallel programming a cumbersome endeavor. As a consequence, compute-intensive sectors in the desktop and server segment have relied on parallelism frameworks such as Intel Threading Building Blocks, Cilk and OpenMP. These parallelism frameworks, however, are optimized for decent average case performance and consequently, do not meet the strict requirements imposed by real-time systems. In this paper, we present a proof-of-concept parallelism framework which was implemented in particular for soft real-time systems and having tight timing and safety requirements of such critical systems in mind. The proposed runtime system implements static memory allocation in a work-stealing environment that conforms to the strict space and tight probabilistic time bounds of work-stealing schedulers. Furthermore, we evaluate the performance of this framework by conducting multiprogrammed benchmarks on a real-time embedded multicore architecture.}, language = {en} } @article{SchmidFritzMottok, author = {Schmid, Michael and Fritz, Florian and Mottok, J{\"u}rgen}, title = {Fine-grained parallelism framework with predictable work-stealing for real-time multiprocessor systems}, series = {Journal of Systems Architecture}, volume = {124}, journal = {Journal of Systems Architecture}, number = {March}, publisher = {Elsevier}, doi = {10.1016/j.sysarc.2022.102393}, abstract = {Lately, parallel task models have received much attention in the development of real-time multiprocessor systems, as they allow highly compute-intensive tasks to have shorter deadlines which is very much required in modern reactive systems. However, missing modularity and portability can make parallel programming a cumbersome endeavor. As a consequence, compute-intensive sectors in the desktop and server segment have relied on parallelism frameworks such as Intel Threading Building Blocks, Cilk and OpenMP. These parallelism frameworks, however, are optimized for decent average case performance and consequently, do not meet the strict requirements imposed by real-time systems. In this paper, we present a proof-of-concept parallelism framework which was implemented in particular for soft real-time systems and having tight timing and safety requirements of such critical systems in mind. The proposed runtime system implements static memory allocation in a work-stealing environment that conforms to the strict space and tight probabilistic time bounds of work-stealing schedulers. Furthermore, we evaluate the performance of this framework by conducting multiprogrammed benchmarks on a real-time embedded multicore architecture.}, language = {en} } @article{StadlerCornetFrenkler, author = {Stadler, Sebastian and Cornet, Henriette and Frenkler, Fritz}, title = {Assessing Heuristic Evaluation in Immersive Virtual Reality: A Case Study on Future Guidance Systems}, series = {Multimodal Technologies and Interaction}, volume = {7}, journal = {Multimodal Technologies and Interaction}, number = {2}, issn = {2414-4088}, doi = {10.3390/mti7020019}, pages = {19}, abstract = {A variety of evaluation methods for user interfaces (UI) exist such as usability testing, cognitive walkthrough, and heuristic evaluation. However, UIs such as guidance systems at transit hubs must be evaluated in their intended application field to allow the effective and valid identification of usability flaws. However, what if evaluations are not feasible in real environments, or laboratorial conditions cannot be ensured? Based on adapted heuristics, in the present study, the method of heuristic evaluation is combined with immersive Virtual Reality (VR) for the identification of usability flaws of dynamic guidance systems (DGS) at transit hubs. The study involved usability evaluations of nine DGS concepts using the newly proposed method. The results show that compared to computer-based heuristic evaluations, the use of immersive VR led to the identification of an increased amount of "severe" usability flaws as well as overall usability flaws. Within a qualitative assessment, immersive VR is validated as a suitable tool for conducting heuristic evaluations involving significant advantages such as the creation of realistic experiences in laboratorial conditions. Future work seeks to further prove the suitability of using immersive VR for heuristic evaluations and compare the proposed method to other evaluative methods.}, language = {en} } @article{CornetStadlerKongetal., author = {Cornet, Henriette and Stadler, Sebastian and Kong, Penny and Marinkovic, Goran and Frenkler, Fritz and Sathikh, Peer Mohideen}, title = {User-centred design of autonomous mobility for public transportation in Singapore}, series = {Transportation Research Procedia}, volume = {41}, journal = {Transportation Research Procedia}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2352-1465}, doi = {10.1016/j.trpro.2019.09.038}, pages = {191 -- 203}, abstract = {The paper presents a set of methods for user-centred design of autonomous mobility for public transportation in the context of a multi-disciplinary research programme in Singapore, called TUMCREATE. While traffic engineers plan the operation of the new mobility system, the Industrial Designers of TUMCREATE take on the role of designing the autonomous vehicles (AVs) and infrastructure for greater comfort and a positive travel experience for users. Tasks have been identified to promote user acceptance and facilitate the operation of autonomously driven vehicles for public transport. To fulfil these tasks, conventional design methods have been enhanced with Virtual Reality (VR) technology and with simulations developed by the computer scientists of TUMCREATE. Since public transportation is a complex and broad area, it cannot be investigated with a single design method. First results showed that conventional methods that consider the Universal Design principles guarantee the accessibility, usability and understandability of AVs and stations. VR has been identified as a suitable tool for Industrial Designers to evaluate communication concepts between AVs and pedestrians. This confirms that digital tools (i.e. VR) enhance conventional design methods, especially with regard to technologies that are not available on the market yet (e.g. AVs)}, language = {en} } @inproceedings{StadlerCornetFrenkler, author = {Stadler, Sebastian and Cornet, Henriette and Frenkler, Fritz}, title = {Collecting People's Preferences in Immersive Virtual Reality: A Case Study on Public Spaces in Singapore, Germany, and France}, series = {Synergy - DRS International Conference 2020, 11-14 August, held online}, booktitle = {Synergy - DRS International Conference 2020, 11-14 August, held online}, editor = {Boess, S. and Cheung, M and Cain, R.}, publisher = {Design Research Society}, doi = {10.21606/drs.2020.308}, pages = {1185 -- 1200}, abstract = {In the design of urban public spaces, the inclusion of diverse voices enhances the development of products and services by synchronising designer expertise with people's preferences. Multiple participatory methods exist, each with their respective benefits and drawbacks in terms of the quality of results, time and cost needed for preparing and conducting studies, and knowledge required for participation. Providing more concrete representations of abstract or intangible design concepts would be beneficial for laypeople unfamiliar with design or the case study. We propose a Virtual Reality (VR) platform to discover subjective preferences on public waiting rooms through immersive design experiences. The VR platform was tested with 463 participants with variety in age and cultural background. Following a qualitative data analysis, we discuss the suitability of our VR platform for fostering inclusive participation and how it impacts the role of the designer, as well as propose design guidelines for future VR studies.}, language = {en} } @incollection{StadlerFrenklerCornet, author = {Stadler, Sebastian and Frenkler, Fritz and Cornet, Henriette}, title = {Design Thinking und Virtual Reality zur F{\"o}rderung von Innovation innerhalb von Unternehmen}, series = {Intrapreneurship : Unternehmergeist Systeme und Gestaltungsm{\"o}glichkeiten}, booktitle = {Intrapreneurship : Unternehmergeist Systeme und Gestaltungsm{\"o}glichkeiten}, editor = {Kraus, Rafaela and Kreitenweis, Tanja and Jeraj, Brigita}, publisher = {Springer Gabler}, address = {Berlin}, isbn = {978-3-662-64101-9}, doi = {10.1007/978-3-662-64102-6_10}, pages = {147 -- 164}, abstract = {Neue Herangehensweisen im Innovationsprozess werden f{\"u}r Unternehmen immer wichtiger, um konkurrenzf{\"a}hig zu bleiben. So bezeichnet Intrapreneurship das Vorgehen, Angestellte innerhalb von Unternehmen selbst als Unternehmerinnen und Unternehmer agieren zu lassen, um so Innovation zu f{\"o}rdern. Der Begriff Design Thinking beschreibt ein Vorgehen, mit Hilfe dessen uneindeutig definierte Probleme behandelt und nutzerzentrierte Produkte entwickelt werden k{\"o}nnen. Die Pr{\"a}misse dieses Beitrags ist es, dass die Kombination von neuartigen Technologien und besonders Virtual Reality mit Design Thinking den Innovationsprozess innerhalb von Unternehmen f{\"o}rdern kann. Anhand zweier Fallbeispiele wird dargestellt, dass neben Nachteilen technischer Natur besonders die M{\"o}glichkeit fiktive Szenarien in VR darzustellen und valide Nutzerdaten in labor{\"a}hnlichen Verh{\"a}ltnissen zu sammeln, Innovation in Unternehmen anregen kann. In weiteren Schritten soll die Nutzung von Design Thinking und Virtual Reality in neuen Applikationsdom{\"a}nen sowie die Nutzung weiterer Designmethoden untersucht werden.}, language = {en} } @inproceedings{StadlerBraunFrenkler, author = {Stadler, Sebastian and Braun, Carmen and Frenkler, Fritz}, title = {The Usage of Mixed Reality for Presentations: A Comparative Evaluation}, series = {XR and Metaverse : Proceedings of the 8th International XR-Metaverse Conference 2023, Las Vegas, USA}, booktitle = {XR and Metaverse : Proceedings of the 8th International XR-Metaverse Conference 2023, Las Vegas, USA}, editor = {Dieck, M. Claudia tom and Jung, Timothy and Kim, Yen-Soon}, publisher = {Springer Nature}, isbn = {978-3-031-50558-4}, doi = {10.1007/978-3-031-50559-1_6}, pages = {77 -- 86}, language = {en} } @incollection{SternerBauerCrotoginoetal., author = {Sterner, Michael and Bauer, Franz and Crotogino, Fritz and Eckert, Fabian and von Olshausen, Christian and Teichmann, Daniel and Thema, Martin}, title = {Chemical Energy Storage}, series = {Handbook of Energy Storage}, booktitle = {Handbook of Energy Storage}, editor = {Sterner, Michael and Stadler, Ingo}, publisher = {Springer}, address = {Berlin, Heidelberg}, isbn = {978-3-662-55503-3}, doi = {10.1007/978-3-662-55504-0_8}, pages = {325 -- 482}, abstract = {Purely electrical energy storage technologies are very efficient, however they are also very expensive and have the smallest capacities. Electrochemical-energy storage reaches higher capacities at smaller costs, but at the expense of efficiency. This pattern continues in a similar way for chemical-energy storage. In terms of capacities, the limits of batteries (accumulators) are reached when low-loss long-term storage is of need. Chemical-energy storage and stocking fulfills these requirements completely. The storing itself may be subject to significant efficiency losses, but, from today's point of view and in combination with the existing gas and fuel infrastructure, it is the only national option with regards to the long-term storage of renewable energies. Chemical-energy storage is the backbone of today's conventional energy supply. Solid (wood and coal), liquid (mineral oil), and gaseous (natural gas) energy carriers are 'energy storages' themselves, and are stored using different technologies. In the course of energy transition, chemical-energy storage will be of significant importance, mainly as long-term storage for the power sector, but also in the form of combustibles and fuels for transport and heat. Not only are conventional storing technologies discussed within this chapter, but a detailed explanation is also given about the storage of renewable energies in the form of gaseous (power-to-gas, PtG) and liquid (power-to-liquid, PtL) energy carriers for electricity, heat, chemicals, and in the form of synthetic fuels.}, language = {en} } @incollection{SternerBauerCrotoginoetal., author = {Sterner, Michael and Bauer, Franz and Crotogino, Fritz and Eckert, Fabian and von Olshausen, Christian and Teichmann, Daniel and Thema, Martin}, title = {Chemische Energiespeicher}, series = {Energiespeicher - Bedarf, Technologien, Integration}, booktitle = {Energiespeicher - Bedarf, Technologien, Integration}, edition = {2. Auflage}, publisher = {Springer Vieweg}, address = {Berlin ; Heidelberg}, isbn = {978-3-662-48893-5}, doi = {10.1007/978-3-662-48893-5_8}, pages = {327 -- 493}, subject = {Energiespeicher}, language = {de} } @inproceedings{StadlerCornetMazeasetal., author = {Stadler, Sebastian and Cornet, Henriette and Mazeas, Damien and Chardonnet, Jean-Remy and Frenkler, Fritz}, title = {IMPRO: IMMERSIVE PROTOTYPING IN VIRTUAL ENVIRONMENTS FOR INDUSTRIAL DESIGNERS}, series = {Proceedings of the Design Society: DESIGN Conference 2020}, booktitle = {Proceedings of the Design Society: DESIGN Conference 2020}, publisher = {Cambridge University Press}, doi = {10.1017/dsd.2020.81}, pages = {1375 -- 1384}, abstract = {Computer-Aided Design (CAD) constitutes an important tool for industrial designers. Similarly, Virtual Reality (VR) has the capability to revolutionize how designers work with its increased sense of scale and perspective. However, existing VR CAD applications are limited in terms of functionality and intuitive control. Based on a comparison of VR CAD applications, ImPro, a new application for immersive prototyping for industrial designers was developed. The user evaluations and comparisons show that ImPro offers increased usability, functionality, and suitability for industrial designers.}, language = {de} } @incollection{GoertlerReheis, author = {G{\"o}rtler, Michael and Reheis, Fritz}, title = {Ressourcen weiter denken. Zur Zeitlichkeit der Sozialen Arbeit im Kontext der Nachhaltigkeitstransformation}, series = {Die Nachhaltigkeitsziele der UN im Spiegel der Wissenschaft : Beispiele aus der Sozial- und Gesundheitsforschung}, booktitle = {Die Nachhaltigkeitsziele der UN im Spiegel der Wissenschaft : Beispiele aus der Sozial- und Gesundheitsforschung}, editor = {Heese, Carl and Sch{\"u}tz, Sandra and Obergrießer, Stefanie}, publisher = {Springer VS}, address = {Wiesbaden}, isbn = {978-3-658-43333-8}, issn = {2731-8834}, doi = {10.1007/978-3-658-43334-5_21}, pages = {373 -- 389}, abstract = {Soziale Arbeit kann aus der Perspektive einer zeit{\"o}kologisch fundierten Resonanztheorie einen Beitrag zur Nachhaltigkeitstransformation leisten. Zugrunde liegt die These, dass f{\"u}r die Soziale Arbeit ein theoretischer Ansatz gewinnbringend ist, der die Zeitlichkeit von Mensch, Gesellschaft und Natur - und damit auch der Nachhaltigen Entwicklung und der Sozialen Arbeit selbst - ins Zentrum stellt. Vor diesem Hintergrund werden die Zeitlichkeit der Nachhaltigen Entwicklung und der Sozialen Arbeit im Kontext der Nachhaltigkeitstransformation herausgearbeitet, theoretische Ans{\"a}tze zu Zeit und Ressourcen diskutiert und eine m{\"o}gliche Verkn{\"u}pfung beider Begriffe am Beispiel von Resonanz, Bildung und Zeit skizziert.}, language = {de} } @article{FritzReisAdamsetal., author = {Fritz, D. M. and Reis, D. A. and Adams, B. and Akre, R. A. and Arthur, J. and Blome, Christian and Bucksbaum, P. H. and Cavalieri, A. L. and Engemann, S. and Fahy, S. and Falcone, R. W. and Fuoss, P. H. and Gaffney, K. J. and George, M. J. and Hajdu, J. and Hertlein, M. P. and Hillyard, P. B. and Horn-von Hoegen, Michael and Kammler, Martin and Kaspar, J. and Kienberger, R. and Krejcik, P. and Lee, S. H. and Lindenberg, A. M. and McFarland, B. and Meyer, D. and Montagne, T. and Murray, E. D. and Nelson, A. J. and Nicoul, Matthieu and Pahl, R. and Rudati, J. and Schlarb, H. and Siddons, D. P. and Sokolowski-Tinten, Klaus and Tschentscher, Th and von der Linde, D. and Hastings, J. B.}, title = {Ultrafast bond softening in bismuth: mapping a solid's interatomic potential with X-rays}, series = {Science}, volume = {315}, journal = {Science}, number = {5812}, publisher = {AAAS}, doi = {10.1126/science.1135009}, pages = {633 -- 636}, abstract = {Intense femtosecond laser excitation can produce transient states of matter that would otherwise be inaccessible to laboratory investigation. At high excitation densities, the interatomic forces that bind solids and determine many of their properties can be substantially altered. Here, we present the detailed mapping of the carrier density-dependent interatomic potential of bismuth approaching a solid-solid phase transition. Our experiments combine stroboscopic techniques that use a high-brightness linear electron accelerator-based x-ray source with pulse-by-pulse timing reconstruction for femtosecond resolution, allowing quantitative characterization of the interatomic potential energy surface of the highly excited solid.}, language = {en} } @misc{StadlerCornetHuangetal., author = {Stadler, Sebastian and Cornet, Henriette and Huang, Danqing and Frenkler, Fritz}, title = {Designing Tomorrow's Human-Machine Interfaces in Autonomous Vehicles: an Exploratory Study in Virtual Reality}, series = {Augmented Reality and Virtual Reality: Changing Realities in a Dynamic World}, journal = {Augmented Reality and Virtual Reality: Changing Realities in a Dynamic World}, editor = {Jung, Timothy and tom Dieck, M. Claudia and Rauschnabel, Philipp A.}, publisher = {Springer}, isbn = {978-3-030-37869-1}, doi = {10.1007/978-3-030-37869-1_13}, pages = {151 -- 160}, abstract = {Technical advances in the automotive industry strive in the direction of full automation. However, besides advantages like improving traffic and fuel efficiency, people do not always trust Autonomous Vehicles (AVs) to make critical decisions. With the ultimate goal of reducing anxiety of passengers of AVs, this explorative study (i) proposes possible design concepts and variants for Human-Machine Interfaces (HMI) for passengers inside the AV using a requirements catalogue, (ii) evaluates the HMI concepts and variants thanks to an experience simulation in Virtual Reality (VR), and (iii) derives the most suitable HMI concept and refines it based on observations of participants' behaviours during the experience simulation in VR, as well as questionnaires and interviews. The results show that the HMI concepts help passengers to reduce anxiety in the AV. Overall, VR turned out to be a suitable tool for this exploratory study. Further work will focus on testing HMI concepts in a variety of more complex scenarios to ensure user acceptance.}, language = {en} }