3,230 research outputs found

    Dynamic Time-Dependent Route Planning in Road Networks with User Preferences

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    There has been tremendous progress in algorithmic methods for computing driving directions on road networks. Most of that work focuses on time-independent route planning, where it is assumed that the cost on each arc is constant per query. In practice, the current traffic situation significantly influences the travel time on large parts of the road network, and it changes over the day. One can distinguish between traffic congestion that can be predicted using historical traffic data, and congestion due to unpredictable events, e.g., accidents. In this work, we study the \emph{dynamic and time-dependent} route planning problem, which takes both prediction (based on historical data) and live traffic into account. To this end, we propose a practical algorithm that, while robust to user preferences, is able to integrate global changes of the time-dependent metric~(e.g., due to traffic updates or user restrictions) faster than previous approaches, while allowing subsequent queries that enable interactive applications

    Novel miscanthus germplasm-based value chains : A Life Cycle Assessment

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    The OPTIMISC project received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement No. 289159. In addition, the study was partly supported by a grant from the Ministry of Science, Research and the Arts of Baden-WĂŒrttemberg (funding code: 7533-10-5-70) as part of the BBW ForWerts Graduate Programme. We are grateful to Nicole Gaudet for editing the manuscript.Peer reviewedPublisher PD

    Consumption Profiles in Route Planning for Electric Vehicles: Theory and Applications

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    In route planning for electric vehicles (EVs), consumption profiles are a functional representation of optimal energy consumption between two locations, subject to initial state of charge. Efficient computation of profiles is a relevant problem on its own, but also a fundamental ingredient to many route planning approaches for EVs. In this work, we show that the complexity of a profile is at most linear in the graph size. Based on this insight, we derive a polynomial-time algorithm for the problem of finding an energy-optimal path between two locations that allows stops at charging stations. Exploiting efficient profile search, our approach also allows partial recharging at charging stations to save energy. In a sense, our results close the gap between efficient techniques for energy-optimal routes (based on simpler models) and NP-hard time-constrained problems involving charging stops for EVs. We propose a practical implementation, which we carefully integrate with Contraction Hierarchies and A* search. Even though the practical variant formally drops correctness, a comprehensive experimental study on a realistic, large-scale road network reveals that it always finds the optimal solution in our tests and computes even long-distance routes with charging stops in less than 300 ms

    Modeling and Engineering Constrained Shortest Path Algorithms for Battery Electric Vehicles

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    We study the problem of computing constrained shortest paths for battery electric vehicles. Since battery capacities are limited, fastest routes are often infeasible. Instead, users are interested in fast routes where the energy consumption does not exceed the battery capacity. For that, drivers can deliberately reduce speed to save energy. Hence, route planning should provide both path and speed recommendations. To tackle the resulting NP-hard optimization problem, previous work trades correctness or accuracy of the underlying model for practical running times. In this work, we present a novel framework to compute optimal constrained shortest paths for electric vehicles that uses more realistic physical models, while taking speed adaptation into account. Careful algorithm engineering makes the approach practical even on large, realistic road networks: We compute optimal solutions in less than a second for typical battery capacities, matching performance of previous inexact methods. For even faster performance, the approach can easily be extended with heuristics that provide high quality solutions within milliseconds

    Preservice Physical Education Teachers’ Digital Literacy

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    Introduction and theoretical framework Teachers play a central role in the process of digitalizing education (Wohlfart & Wagner, 2022). However, international studies confirm that teachers in Germany have low digital skills and rarely use digital tools in teaching (Eickelmann et al., 2019). Therefore, this study investigates how digitally competent trainee teachers in the subject of physical ed-ucation assess themselves and analyzes the interdependency of digital literacy, role modeling by university lecturers, and intended integration of ICT in future teaching. The Technological Pedagogical Content Knowledge (TPACK) framework guided the study (Mishra & Koehler, 2006). Method A 50-item questionnaire based on Schmidt et al.’s (2009) validated TPACK questionnaire was administered to a subject-specific sample of all 185 pre-service physical education teachers in Baden-WĂŒrttemberg, Germany. The survey included questions on de-mographics, education-specific information, content- and context-related information as-sociated with the TPACK model (scale from 1=disagree to 5=agree fully), and role model-ling of ICT integration in higher education and in respondents’ own intended practice. Results The results show that the pre-service physical education teachers feel better prepared in terms of content knowledge (CK; m=4,25, SD=0,53) above pedagogical knowledge (PK; m=3,81, SD=0,55) for an increasingly digital educational environment. While they feel confident in conveying content knowledge in a pedagogic manner (PCK; m=3,96, SD=0,59), the integration of technology highlighted both lower values and more variance in the self-assessment (TK, TPK, TCK, TPACK; m=3,30-3,57; 0,63-0,76). The correlation analysis of the knowledge domains shows significant correlations between the seven knowledge domains with moderate to large effect. Finally, the results of the regression models show a positive effect of CK and PK on overall intent to integrate ICT in teaching (R2 = 0.178, adjusted R2 = 0.163, p < .05) and the results further indicate that the effects of role modeling depend on the choice of ICT. Discussion PK and CK (rather than self-assessment within the technology-specific dimensions) had a positive impact on the intent to integrate ICT in PE. While the consideration of ICT in the classroom still represents a barrier, specific support for the pedagogical implementation of ICT (TPK) may have a (subject-specific) positive influence on TPACK. Further, the results confirmed the positive effect of teacher educators\u27 role modeling on digital literacy and general ICT integration intent, including specific types of ICT. We discuss the potential implications of inadequate role modeling on pre-service teachers and PE instruction. References Eickelmann, B., Bos, W., Gerick, J., Goldhammer, F., Schaumburg, H., Schwippert, K. & Vahrenhold, J. (2019). ICILS 2018# Deutschland. Computer-und informationsbezogene Kompetenzen von SchĂŒlerinnen und SchĂŒlern im zweiten internationalen Vergleich und Kompetenzen im Bereich Computational Thinking. MĂŒnster. Mishra, P. & Koehler, M. (2006). Technological Pedagogical Content Knowledge: A Framework for Teacher Knowledge. Teachers College Record, 108, 1017-1054. Schmidt, D. A., Baran, E., Thompson, A. D., Mishra, P., Koehler, M. J., & Shin, T. S. (2009). Technological Pedagogical Content Knowledge (TPACK). Journal of Research on Technology in Education, 42(2), 123–149. https://doi.org/https://doi.org/10.1080/15391523.2009.10782544 Wohlfart, O., & Wagner, I. (2022). Teachers\u27 role in digitalizing education: An umbrella review. Educational Technology Research and Development. https://doi.org/10.1007/s11423-022-10166-

    Video-based visual feedback to enhance motor learning in physical education—a systematic review [Videobasiertes visuelles Feedback zur Verbesserung des motorischen Lernens im Sportunterricht – ein systematisches Review]

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    While studies have indicated that visual feedback promotes skill acquisition and motor learning in controlled settings and for various sports, less is known about its feasibility in physical education, which has specific needs and conditions. For this reason, a systematic literature review was conducted regarding video-based visual feedback in physical education. Out of 2030 initially examined studies, 11 matched the selection and quality criteria. The goal was to determine whether visual feedback can be effective regarding motor learning in physical education in primary and secondary schools, and to investigate whether different visual feedback variants (expert modeling and self-modeling), supported by verbal feedback, are more effective than verbal feedback alone. Subsequently, the different conditions (e.g., age, group size, duration) of the included studies were evaluated for their suitability for everyday applications. Video-based visual feedback seems to be effective to enhance motor learning in physical education and seems to be more effective than solely verbal feedback. However, the results show that the specific conditions (class size, scheduled lessons, available time, technical equipment, the digital literacy of teachers, and data protection) of a school environment must be considered before implementing visual video feedback in daily practice

    Information and communication technologies in physical education: Exploring the association between role modeling and digital literacy

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    Teacher educators should serve as role models in terms of information and communication technologies (ICTs) use to promote digital literacy of future teachers. To analyze the association between role modeling by teacher educators and preservice teachers’ digital literacy and ICT integration intention in their classrooms, 185 physical education (PE) preservice teachers in the German federal state of Baden-WĂŒrttemberg completed an online questionnaire of self-assessed technological, pedagogical, and content knowledge (TPACK) and ICT integration. The results of regression models revealed a positive association between content knowledge and pedagogical knowledge (PK) and overall intent to integrate ICT into teaching. The results further indicated that the impact of role modeling on preservice teachers varies depending on the chosen ICT. In this paper, we discuss the implications of these findings for higher education in general and for PE in particular

    Einfluss des Wachstums-Differenzierungs-Faktors-15 (GDF-15) auf die Gen- und Proteinexpression des Musculus gastrocnemius bei hypercholesterinÀmischen (knockout) MÀusen.

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    Einleitung: Der Wachstums-Differenzierungs-Faktor-15 (GDF-15) gehört zur TGF-ÎČ-Superfamilie und wird bei EntzĂŒndungen und Stressexposition insbesondere von Makrophagen, GefĂ€ĂŸmuskelzellen, Kardiomyozyten, Adipozyten und Endothelzellen vermehrt exprimiert (Schlittenhardt et al., 2004; Bauskin et al., 2005; BermĂșdez et al., 2008; Ding et al., 2009; Adela and Banerjee, 2015). In frĂŒheren Arbeiten haben wir gezeigt, dass die Protein- und mRNA-Expression von GDF-15 in arteriosklerotischen GefĂ€ĂŸwĂ€nden induziert und dort in Makrophagen lokalisiert ist (Schlittenhardt et al., 2004; Bonaterra et al., 2012). GDF-15 dient als neuer Biomarker fĂŒr kardiovaskulĂ€ren Stress und ist u.a. mit Herzinsuffizienz und kardialem Remodeling assoziiert (Andersson et al., 2016; Meijers et al., 2016). Außerdem wurde gefunden, dass bei GDF-15-Defizienz die Entstehung und Progression der Arteriosklerose gehemmt ist (de Jager et al., 2011; Bonaterra et al., 2012). In der vorliegenden Studie sollte der Einfluss von GDF-15 auf die Expression inflammatorischer, angiogenetischer, apoptotischer bzw. atrophischer Gene/Proteine in der Skelettmuskulatur bei cholesteringefĂŒtterten MĂ€usen in einem Mausmodell fĂŒr experimentelle Arteriosklerose (ApoE-/-) untersucht werden. Material und Methoden: Mithilfe eines LacZknockin-Konstrukts wurden GDF-15-defiziente MĂ€use generiert (Strelau et al., 2009) und anschließend mit ApoE-/--MĂ€usen gekreuzt, sodass folgende Genotypen zur VerfĂŒgung standen: GDF-15+/+/ApoE+/+ (Wildtyp), GDF-15-/-/ApoE+/+, GDF-15+/+/ApoE-/- und GDF-15-/-/ApoE-/-. Im Alter von zehn Wochen wurden die Tiere mit einem cholesterinreichen Futter (CHF) ĂŒber einen Zeitraum von 12 bzw. 20 Wochen gefĂŒttert. Das Gewicht sowie die Serum-Cholesterin- und -Triglyzeridspiegel der MĂ€use wurden dabei vor CHF-Gabe und nach 12 bzw. 20 Wochen cholesterinreicher FĂŒtterung bestimmt. Anschließend wurde der M. gastrocnemius entnommen und RNA sowie Proteine isoliert. Die mRNA-Expression von relevanten Genen fĂŒr Inflammation, Apoptose, Angiogenese, Atrophie und nikotinerge Acetylcholin-Rezeptoren (AChR) wurde mithilfe quantitativer Real-Time RT-PCR (qRT-PCR) untersucht. Auf Proteinebene wurden im Skelettmuskel u.a. pro-/anti-inflammatorische Zytokine und pro-/anti-angiogenetische Chemokine mittels „Proteome Profilerℱ Mouse Cytokine Array Kit“-System quantifiziert. Ergebnisse: Das Gewicht war bei GDF-15-/-/ApoE+/+-MĂ€usen nach 20 Wochen CHF (10 %; p≀0,01) und bei GDF-15-/-/ApoE-/--Tieren vor CHF (6 %; p≀0,01) und nach 12 (16 %; p≀0,01) bzw. 20 Wochen CHF (34 %; p≀0,001) höher als bei Wildtyp- bzw. GDF-15+/+/ApoE-/--MĂ€usen (Kubo, 2013). Der Serum-Cholesterinspiegel war bei GDF-15-/-/ApoE-/--MĂ€usen vor CHF (22 %; p≀0,05) und nach 12 (34 %; p≀0,001) bzw. 20 Wochen CHF (14 %; p≀0,05) höher als bei GDF-15+/+/ApoE-/--MĂ€usen (Kubo, 2013). Des Weiteren waren bei GDF-15-/-/ApoE+/+-MĂ€usen nach 12 (54 %; p≀0,05) bzw. 20 Wochen CHF (35 %; p≀0,05) und bei GDF-15-/-/ApoE-/--MĂ€usen nach 20 Wochen CHF (95 %; p≀0,01) die Serum-Triglyzeridspiegel höher als bei Wildtyp- bzw. GDF-15+/+/ApoE-/--MĂ€usen (Kubo, 2013). Nach 12 Wochen CHF zeigte die quantitative Real-Time RT-PCR im M. gastrocnemius von GDF-15-/-/ApoE+/+-MĂ€usen eine 21- und 6fach (p≀0,05) höhere IL-6- bzw. IL-1ÎČ-Expression im Vergleich zu Wildtyp-Tieren. Nach 20 Wochen CHF konnte eine 69 % bzw. 98 % (p≀0,05) niedrigere IL-6- bzw. IL-1ÎČ-mRNA-Expression in dieser Gruppe festgestellt werden. Die Expression des pro-apoptotischen Bax-Gens war im M. gastrocnemius von GDF-15-/-/ApoE+/+-MĂ€usen nach 12 Wochen CHF 31fach (p≀0,05) höher als bei Wildtyp-Tieren. DarĂŒber hinaus fanden wir nach 20 Wochen CHF in GDF-15-/-/ApoE-/--MĂ€usen eine 86 % (p≀0,05) niedrigere Bax-Expression als bei GDF-15+/+/ApoE-/--Tieren. Die Expression des pro-angiogenetischen Notch1-Gens war nach 20 Wochen CHF im M. gastrocnemius von GDF-15-/-/ApoE-/--MĂ€usen 97 % (p≀0,05) niedriger als bei GDF-15+/+/ApoE-/--Tieren. Die mRNA-Expression des Fbxo32-Atrophie-Gens war nach 12 Wochen CHF in GDF-15-/-/ApoE+/+-MĂ€usen 23fach höher (p≀0,05) als bei Wildtyp-Tieren. DarĂŒber hinaus zeigte die Untersuchung mittels membranbasiertem Sandwich-Immunassay (Proteome Profilerℱ Mouse Cytokine Array Kit) im M. gastrocnemius von GDF-15-/-/ApoE+/+-MĂ€usen nach 20 Wochen CHF eine 1,5-3,1fach erhöhte Proteinexpression pro-inflammatorischer (z.B. IL-1ÎČ, IL-6, IL-17, IFN-Îł und TNF-α) und eine 1,2-2,5fach erhöhte Proteinexpression anti-inflammatorischer (z.B. IL-4, IL-10 und IL-13) Zytokine im Vergleich zu Wildtyp-Tieren. Im M. gastrocnemius von GDF-15-/-/ApoE-/--MĂ€usen war nach 20 Wochen CHF die Expression sowohl pro- als auch anti-inflammatorischer Proteine 39-85 % im Vergleich zu GDF-15+/+/ApoE-/--Tieren erniedrigt. Die Proteinexpression inflammatorischer und pro-/anti- angiogenetischer Chemokine (z.B. CCL2, CXCL1 und CXCL9) war im M. gastrocnemius von GDF-15-/-/ApoE+/+-MĂ€usen verglichen mit Wildtyp-Tieren nach 20 Wochen CHF 1,1-2,7fach erhöht. GDF-15-/-/ApoE-/--MĂ€use hatten nach 20 Wochen CHF im M. gastrocnemius im Vergleich zu GDF-15+/+/ApoE-/--Tieren eine 45-73 % niedrigere Proteinexpression inflammatorischer und angiogenetischer Chemokine. Schlussfolgerung: GDF-15 scheint im M. gastrocnemius die Expression pro-/anti-inflammatorischer, pro-/anti-angiogenetischer, apoptose- und atrophierelevanter Gene/Proteine abhĂ€ngig von der FĂŒtterungsdauer zu beeinflussen. Des Weiteren moduliert GDF-15 das Gewicht sowie die Serum-Cholesterin- bzw. -Triglyzeridspiegel
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