TY - JOUR A1 - Nobis, Moritz A1 - Schmitt, Carlo A1 - Schemm, Ralf A1 - Schnettler, Armin T1 - Pan-European CVAR-constrained stochastic unit commitment in day-ahead and intraday electricity markets JF - Energies N2 - The fundamental modeling of energy systems through individual unit commitment decisions is crucial for energy system planning. However, current large-scale models are not capable of including uncertainties or even risk-averse behavior arising from forecasting errors of variable renewable energies. However, risks associated with uncertain forecasting errors have become increasingly relevant within the process of decarbonization. The intraday market serves to compensate for these forecasting errors. Thus, the uncertainty of forecasting errors results in uncertain intraday prices and quantities. Therefore, this paper proposes a two-stage risk-constrained stochastic optimization approach to fundamentally model unit commitment decisions facing an uncertain intraday market. By the nesting of Lagrangian relaxation and an extended Benders decomposition, this model can be applied to large-scale, e.g., pan-European, power systems. The approach is applied to scenarios for 2023—considering a full nuclear phase-out in Germany—and 2035—considering a full coal phase-out in Germany. First, the influence of the risk factors is evaluated. Furthermore, an evaluation of the market prices shows an increase in price levels as well as an increasing day-ahead-intraday spread in 2023 and in 2035. Finally, it is shown that intraday cross-border trading has a significant influence on trading volumes and prices and ensures a more efficient allocation of resources. Y1 - 2020 U6 - https://doi.org/10.3390/en13092339 SN - 1996-1073 N1 - Special Issue Uncertainties and Risk Management in Competitive Energy Markets VL - 13 IS - Art. 2339 SP - 1 EP - 35 PB - MDPI CY - Basel ER - TY - JOUR A1 - Stulpe, Werner T1 - Pairwise coexistence of effects versus coexistence JF - Journal of Physics: Conference Series Y1 - 2020 U6 - https://doi.org/10.1088/1742-6596/1638/1/012004 SN - 1742-6596 VL - 1638 IS - 012004 SP - 1 EP - 21 PB - IOP CY - Bristol ER - TY - JOUR A1 - Rausch, Valentin A1 - Harbrecht, Andreas A1 - Kahmann, Stephanie Lucina A1 - Fenten, Thomas A1 - Jovanovic, Nebojsa A1 - Hackl, Michael A1 - Müller, Lars P. A1 - Staat, Manfred A1 - Wegmann, Kilian T1 - Osteosynthesis of Phalangeal Fractures: Biomechanical Comparison of Kirschner Wires, Plates, and Compression Screws JF - The Journal of Hand Surgery N2 - Purpose The aim of this study was to compare several osteosynthesis techniques (intramedullary headless compression screws, T-plates, and Kirschner wires) for distal epiphyseal fractures of proximal phalanges in a human cadaveric model. Methods A total of 90 proximal phalanges from 30 specimens (index, ring, and middle fingers) were used for this study. After stripping off all soft tissue, a transverse distal epiphyseal fracture was simulated at the proximal phalanx. The 30 specimens were randomly assigned to 1 fixation technique (30 per technique), either a 3.0-mm intramedullary headless compression screw, locking plate fixation with a 2.0-mm T-plate, or 2 oblique 1.0-mm Kirschner wires. Displacement analysis (bending, distraction, and torsion) was performed using optical tracking of an applied random speckle pattern after osteosynthesis. Biomechanical testing was performed with increasing cyclic loading and with cyclic load to failure using a biaxial torsion-tension testing machine. Results Cannulated intramedullary compression screws showed significantly less displacement at the fracture site in torsional testing. Furthermore, screws were significantly more stable in bending testing. Kirschner wires were significantly less stable than plating or screw fixation in any cyclic load to failure test setup. Conclusions Intramedullary compression screws are a highly stable alternative in the treatment of transverse distal epiphyseal phalangeal fractures. Kirschner wires seem to be inferior regarding displacement properties and primary stability. Clinical relevance Fracture fixation of phalangeal fractures using plate osteosynthesis may have the advantage of a very rigid reduction, but disadvantages such as stiffness owing to the more invasive surgical approach and soft tissue irritation should be taken into account. Headless compression screws represent a minimally invasive choice for fixation with good biomechanical properties. Y1 - 2020 U6 - https://doi.org/10.1016/j.jhsa.2020.04.010 SN - 0363-5023 VL - 45 IS - 10 SP - 987.e1 EP - 987.e8 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Köhler, Klemens A1 - Wolf, Martin T1 - Organisatorische Maßnahmen zu Erhöhung der IT Sicherheit – Empfehlungen aus der Perspektive der Konflikttheorie N2 - Die NATO definiert den Cyberspace als die "Umgebung, die durch physische und nicht-physische Bestandteile zum Speichern, Ändern, und Austauschen von Daten mit Hilfe von Computer-Netzwerken" [NATO CCDCOE]. Darüber hinaus ist es ein Medium menschlicher Interaktion. IT Angriffe sind feindselige, nichtkooperative Interaktionen, die mittels Konflikttheorie beschrieben werden können. Durch die Anwendung dieses Gedankengebäudes auf IT Sicherheit von Organisationen können eine Reihe von Verbesserungen in Unternehmen identifiziert werden. Y1 - 2020 IS - Preprint ER - TY - JOUR A1 - Müller, Tim M. A1 - Leise, Philipp A1 - Lorenz, Imke-Sophie A1 - Altherr, Lena A1 - Pelz, Peter F. T1 - Optimization and validation of pumping system design and operation for water supply in high-rise buildings JF - Optimization and Engineering N2 - The application of mathematical optimization methods for water supply system design and operation provides the capacity to increase the energy efficiency and to lower the investment costs considerably. We present a system approach for the optimal design and operation of pumping systems in real-world high-rise buildings that is based on the usage of mixed-integer nonlinear and mixed-integer linear modeling approaches. In addition, we consider different booster station topologies, i.e. parallel and series-parallel central booster stations as well as decentral booster stations. To confirm the validity of the underlying optimization models with real-world system behavior, we additionally present validation results based on experiments conducted on a modularly constructed pumping test rig. Within the models we consider layout and control decisions for different load scenarios, leading to a Deterministic Equivalent of a two-stage stochastic optimization program. We use a piecewise linearization as well as a piecewise relaxation of the pumps’ characteristics to derive mixed-integer linear models. Besides the solution with off-the-shelf solvers, we present a problem specific exact solving algorithm to improve the computation time. Focusing on the efficient exploration of the solution space, we divide the problem into smaller subproblems, which partly can be cut off in the solution process. Furthermore, we discuss the performance and applicability of the solution approaches for real buildings and analyze the technical aspects of the solutions from an engineer’s point of view, keeping in mind the economically important trade-off between investment and operation costs. KW - Technical Operations Research KW - MINLP KW - MILP KW - Experimental validation KW - Pumping systems Y1 - 2020 U6 - https://doi.org/10.1007/s11081-020-09553-4 SN - 1573-2924 VL - 2021 IS - 22 SP - 643 EP - 686 PB - Springer ER - TY - JOUR A1 - Engemann, Heiko A1 - Du, Shengzhi A1 - Kallweit, Stephan A1 - Cönen, Patrick A1 - Dawar, Harshal T1 - OMNIVIL - an autonomous mobile manipulator for flexible production JF - Sensors Y1 - 2020 SN - 1424-8220 U6 - https://doi.org/10.3390/s20247249 N1 - Special issue: Sensor Networks Applications in Robotics and Mobile Systems VL - 20 IS - 24, art. no. 7249 SP - 1 EP - 30 PB - MDPI CY - Basel ER - TY - JOUR A1 - Reger, Vitali A1 - Kuhnhenne, Markus A1 - Ebbert, Thiemo A1 - Hachul, Helmut A1 - Blanke, Tobias A1 - Döring, Bernd T1 - Nutzung erneuerbarer Energien durch thermische Aktivierung von Komponenten aus Stahl JF - Stahlbau N2 - Die Versorgung von Neubauten soll möglichst weitgehend unabhängig von fossilen Energieträgern erfolgen. Erneuerbare Energien spielen dafür eine gewichtige Rolle. Eine gute Möglichkeit, erneuerbare Energien ohne viel zusätzlichen Aufwand nutzbar zu machen, ist, bereits vorhandenen Komponenten im Gebäude zusätzliche Funktionen zu geben. Hier kann bspw. die Fassade oder das Dach solarthermisch aktiviert oder durch Fotovoltaikmodule ergänzt werden. Auch Tiefgründungen können neben der statischen Funktion noch eine geothermische Funktion zur Aufnahme oder Abgabe von Wärme erhalten. Neben der Erzeugung bietet sich auch für die Verteilung der Wärme oder Kälte im Gebäude die Integration in Bauteile an. Hier kann bspw. der Boden durch eine Fußbodenheizung oder die Decke durch Deckenstrahlplatten aktiviert werden. Im Rahmen der Veröffentlichung wird auf die thermische Aktivierung von Stahlkomponenten eingegangen. Es wird eine Lösung vorgestellt, die vorgehängte hinterlüftete Stahlfassade (VHF) solarthermisch zu aktivieren. Außerdem werden zwei Möglichkeiten zur geothermischen Aktivierung von Tiefgründungen mittels Stahlpfählen gezeigt. Zuletzt wird ein System zur thermischen Aktivierung von Stahltrapezprofilen an der Decke erläutert, welches Wärme zuführen oder bei Bedarf abführen kann. Y1 - 2020 U6 - https://doi.org/10.1002/stab.202000031 SN - 1437-1049 VL - 2020 IS - Volume 89, Issue 6512-519 SP - 512 EP - 519 PB - Ernst & Sohn CY - Berlin ER - TY - JOUR A1 - Marinković, Marko A1 - Flores Calvinisti, Santiago A1 - Butenweg, Christoph T1 - Numerical analysis of reinforced concrete frame buildings with decoupled infill walls T1 - Numerička analiza armiranobe tonskih okvirnih zgrada sa izolovanom zidanom ispunom JF - Building Materials and Structures JF - Građevinski materijali i konstrukcije N2 - Reinforced concrete (RC) buildings with masonry infill walls are widely used in many countries all over the world. Although infills are considered as non-structural elements, they significantly change dynamic characteristics of RC frame structures during earthquake excitation. Recently, significant effort was spent on studying decoupled infills, which are isolated from the surrounding frame usually by adding a gap between frame and infill. In this case, the frame deformation does not activate infill wall, thus infills are not influencing the behaviour of the frame. This paper presents the results of the investigation of the behaviour of RC frame buildings with the INODIS system that decouples masonry infills from the surrounding frame. Effect of masonry infill decoupling was investigated first on the one-bay onestorey frame. This was used as a base for parametric study on the frames with more bays and storeys, as well as on the building level. Change of stiffness and dynamic characteristics was analysed as well as response under earthquake loading. Comparison with the bare frame and traditionally infilled frame was performed. The results show that behaviour of the decoupled infilled frames is similar to the bare frame, whereas behaviour of frames with traditional infills is significantly different and demands complex numerical models. This means that if adequate decoupling is applied, design of N2 - Armiranobetonske (AB) zgrade sa zidanom ispunom se izvode u mnogim zemljama širom sveta. Iako se zidana ispuna posmatra kao nekonstruktivni element, ona značajno utiče na promenu dinamičkih karakteristika AB ramovskih konstrukcija u toku zemljotresnog dejstva. Odskora, značajan napor je utrošen na istraživanje izolovanih ispuna, koje su odvojene od okolnog rama obično ostavljanjem prostora između rama i ispune. U ovom slučaju deformacija rama ne aktivira ispunu i na taj način ispuna ne utiče na ponašanje rama. Ovaj rad predstavlja rezultate istraživanja ponašanja AB ramovskih zgrada sa INODIS sistemom koji izoluje ispunu u odnosu na okolni ram. Uticaj izolovane ispune je prvo ispitan na jednospratnim i jednobrodnim ramovima. Ovo je iskorišćeno kao osnova za parametarsku analizu na višespratnim i višebrodnim ramovima, kao i na primeru zgrade. Promena krutosti i dinamičkih karakteristika je analizirano kao i odgovor pri zemljotresnom dejstvu. Izvršeno je poređenje sa praznom ramovskom konstrukcijom kao i ramovima ispunjenim ispunom na tradicionalni način. Rezultati pokazuju da je ponašanje ramova sa izolovanom ispunom slično ponašanju praznih ramova, dok je ponašanje ramova sa tradicionalnom ispunom daleko drugačije i zahteva kompleksne numeričke modele. Ovo znači da ukoliko se primeni adekvatna konstruktivna mera izolacije ispune, proračun ramovskim zgrada sa zidanom ispunom se može značajno pojednostaviti. KW - masonry infill KW - seismic KW - INODIS KW - in-plane behaviour KW - out-of-plane behaviour Y1 - 2020 U6 - https://doi.org/10.5937/GRMK2004013M SN - 2217-8139 N1 - Text serbisch, ab 2011 serbisch und englisch VL - 63 IS - 4 SP - 13 EP - 48 PB - Society for Materials and Structures Testing of Serbia CY - Belgrad ER - TY - JOUR A1 - Quittmann, Oliver J. A1 - Meskemper, Joshua A1 - Albracht, Kirsten A1 - Abel, Thomas A1 - Foitschik, Tina A1 - Strüder, Heiko K. T1 - Normalising surface EMG of ten upper-extremity muscles in handcycling: Manual resistance vs. sport-specific MVICs JF - Journal of Electromyography and Kinesiology N2 - Muscular activity in terms of surface electromyography (sEMG) is usually normalised to maximal voluntary isometric contractions (MVICs). This study aims to compare two different MVIC-modes in handcycling and examine the effect of moving average window-size. Twelve able-bodied male competitive triathletes performed ten MVICs against manual resistance and four sport-specific trials against fixed cranks. sEMG of ten muscles [M. trapezius (TD); M. pectoralis major (PM); M. deltoideus, Pars clavicularis (DA); M. deltoideus, Pars spinalis (DP); M. biceps brachii (BB); M. triceps brachii (TB); forearm flexors (FC); forearm extensors (EC); M. latissimus dorsi (LD) and M. rectus abdominis (RA)] was recorded and filtered using moving average window-sizes of 150, 200, 250 and 300 ms. Sport-specific MVICs were higher compared to manual resistance for TB, DA, DP and LD, whereas FC, TD, BB and RA demonstrated lower values. PM and EC demonstrated no significant difference between MVIC-modes. Moving average window-size had no effect on MVIC outcomes. MVIC-mode should be taken into account when normalised sEMG data are illustrated in handcycling. Sport-specific MVICs seem to be suitable for some muscles (TB, DA, DP and LD), but should be augmented by MVICs against manual/mechanical resistance for FC, TD, BB and RA. Y1 - 2020 U6 - https://doi.org/10.1016/j.jelekin.2020.102402 SN - 1050-6411 VL - 51 IS - Article 102402 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Gerhards, Michael A1 - Sander, Volker A1 - Zivkovic, Miroslav A1 - Belloum, Adam A1 - Bubak, Marian T1 - New approach to allocation planning of many‐task workflows on clouds JF - Concurrency and Computation: Practice and Experience N2 - Experience has shown that a priori created static resource allocation plans are vulnerable to runtime deviations and hence often become uneconomic or highly exceed a predefined soft deadline. The assumption of constant task execution times during allocation planning is even more unlikely in a cloud environment where virtualized resources vary in performance. Revising the initially created resource allocation plan at runtime allows the scheduler to react on deviations between planning and execution. Such an adaptive rescheduling of a many-task application workflow is only feasible, when the planning time can be handled efficiently at runtime. In this paper, we present the static low-complexity resource allocation planning algorithm (LCP) applicable to efficiently schedule many-task scientific application workflows on cloud resources of different capabilities. The benefits of the presented algorithm are benchmarked against alternative approaches. The benchmark results show that LCP is not only able to compete against higher complexity algorithms in terms of planned costs and planned makespan but also outperforms them significantly by magnitudes of 2 to 160 in terms of required planning time. Hence, LCP is superior in terms of practical usability where low planning time is essential such as in our targeted online rescheduling scenario. Y1 - 2020 U6 - https://doi.org/10.1002/cpe.5404 SN - 1532-0634 VL - 32 IS - 2 Article e5404 SP - 1 EP - 16 PB - Wiley CY - Chichester ER -