TY - JOUR A1 - Heuermann, Holger A1 - Schiek, Burkhard T1 - Calibration of network analyser measurements with leakage errors JF - Electronics letters. 30 (1994), H. 1 Y1 - 1994 SN - 0013-5194 SP - 52 EP - 53 ER - TY - JOUR A1 - Limpert, Nicolas A1 - Wiesen, Patrick A1 - Ferrein, Alexander A1 - Kallweit, Stephan A1 - Schiffer, Stefan T1 - The ROSIN Project and its Outreach to South Africa JF - R&D Journal Y1 - 2019 VL - 35 SP - 1 EP - 6 ER - TY - JOUR A1 - Ferrein, Alexander A1 - Schiffer, Stefan A1 - Booysen, T. A1 - Stopforth, R. T1 - Why it is harder to run RoboCup in South Africa: Experiences from German South African collaborations JF - International Journal of Advanced Robotic Systems N2 - Robots are widely used as a vehicle to spark interest in science and technology in learners. A number of initiatives focus on this issue, for instance, the Roberta Initiative, the FIRST Lego League, the World Robot Olympiad and RoboCup Junior. Robotic competitions are valuable not only for school learners but also for university students, as the RoboCup initiative shows. Besides technical skills, the students get some project exposure and experience what it means to finish their tasks on time. But qualifying students for future high-tech areas should not only be for students from developed countries. In this article, we present our experiences with research and education in robotics within the RoboCup initiative, in Germany and South Africa; we report on our experiences with trying to get the RoboCup initiative in South Africa going. RoboCup has a huge support base of academic institutions in Germany; this is not the case in South Africa. We present our ‘north–south’ collaboration initiatives in RoboCup between Germany and South Africa and discuss some of the reasons why we think it is harder to run RoboCup in South Africa. Y1 - 2016 U6 - https://doi.org/10.1177/1729881416662789 SN - 1729-8806 VL - 13 IS - 5 SP - 1 EP - 13 ER - TY - JOUR A1 - Alhwarin, Faraj A1 - Ferrein, Alexander A1 - Scholl, Ingrid T1 - IR stereo kinect: improving depth images by combining structured light with IR stereo Y1 - 2014 SP - 1 EP - 9 ER - TY - JOUR A1 - Hüning, Felix A1 - Heuermann, Holger A1 - Wache, Franz-Josef T1 - Wireless CAN without WLAN or Bluetooth JF - CAN Newsletter N2 - In two developed concepts, dual-mode radio enables CAN participants to be integrated wirelessly into a CAN network. Constructed from a few components, a protocol-free, real-time transmission and thus transparent integration into CAN is provided. Y1 - 2018 IS - December 2018 SP - 44 EP - 46 ER - TY - JOUR A1 - Ferrein, Alexander A1 - Strack, Andreas A1 - Lakemeyer, Gerhard T1 - Laser-Based Localization with Sparse Landmarks / Strack, Andreas ; Ferrein, Alexander ; Lakemeyer, Gerhard JF - RoboCup 2005: Robot Soccer World Cup IX Y1 - 2006 SN - 978-3-540-35437-6 N1 - Lecture Notes in Computer Science ; 4020 SP - 569 EP - 576 PB - Springer CY - Berlin ER - TY - JOUR A1 - Vorst, Phillip A1 - Ferrein, Alexander A1 - Lakemeyer, Gerhard T1 - AllemaniACs3D team description Y1 - 2006 SP - 1 EP - 6 ER - TY - JOUR A1 - Ferrein, Alexander A1 - Schiffer, Stefan A1 - Lakemeyer, Gerhard T1 - Qualitative World Models for Soccer Robots / Schiffer, Stefan ; Ferrein, Alexander ; Lakemeyer, Gerhard JF - Qualitative constraint calculi : application and integration ; KI 2006, 14 - 19 June 2006, Bremen, Germany ; 29th Annual German Conference on Artificial Intelligence ; workshop / Stefan Wölfl ... (eds.) Y1 - 2006 SN - 3-88722-666-6 SP - 3 EP - 14 PB - Univ. CY - Bremen ER - TY - JOUR A1 - Heuermann, Holger A1 - Ibrahim, Irfan A1 - Hillebrand, J. T1 - Vector-Signal-Generator with Two ¿¿-PLL's / Ibrahim, I. ; Hillebrand, J. ; Heuermann, H. JF - European Conference on Wireless Technologies, 2007. ECWT 2007 ; 8 - 10 October 2007 Munich, Germany Y1 - 2007 SN - 978-2-87487-003-3 SP - 1 EP - 4 ER - TY - JOUR A1 - Hofmann, Till A1 - Limpert, Nicolas A1 - Mataré, Victor A1 - Schönitz, Sebastian A1 - Niemueller, Tim A1 - Ferrein, Alexander A1 - Lakemeyer, Gerhard T1 - The Carologistics RoboCup Logistics Team 2018 N2 - The Carologistics team participates in the RoboCup Logistics League for the seventh year. The RCLL requires precise vision, manipulation and path planning, as well as complex high-level decision making and multi-robot coordination. We outline our approach with an emphasis on recent modifications to those components. The team members in 2018 are David Bosen, Christoph Gollok, Mostafa Gomaa, Daniel Habering, Till Hofmann, Nicolas Limpert, Sebastian Schönitz, Morian Sonnet, Carsten Stoffels, and Tarik Viehmann. This paper is based on the last year’s team description. Y1 - 2018 ER - TY - JOUR A1 - Ferrein, Alexander A1 - Schiffer, Stefan A1 - Lakemeyer, Gerhard T1 - A Fuzzy Set Semantics for Qualitative Fluents in the Situation Calculus / Ferrein, Alexander ; Schiffer, Stefan ; Lakemeyer, Gerhard JF - Intelligent Robotics and Applications : First International Conference, ICIRA 2008 Wuhan, China, October 15-17, 2008 Proceedings, Part I Y1 - 2008 N1 - Lecture Notes in Computer Science ; 5314 SP - 498 EP - 509 PB - Springer CY - Berlin ER - TY - JOUR A1 - Wolf, Martin R. A1 - Foltz, Christian A1 - Schlick, Christopher A1 - Luczak, Holger T1 - Empirical Investigation of a workspace model for Chemical engineers / Wolf, Martin ; Foltz, Christian ; Schlick, Christopher ; Luczak, Holger JF - Proceedings of the Human Factors and Ergonomics Society Annual Meeting July 2000. 44 (2000), H. 6 Y1 - 2000 N1 - Proceedings of the IEA 2000/HFES 2000 Congress SP - 612 EP - 615 PB - - ER - TY - JOUR A1 - Schiffer, Stefan A1 - Ferrein, Alexander A1 - Lakemeyer, Gerhard T1 - Abstracting Away Low-Level Details in Service Robotics with Fuzzy Fluents JF - Model-Driven Knowledge Engineering for Improved Software Modularity in Robotics and Automation. Workshop at European Robotics Forum 2015 Vienna, Austria, March 11-13, 2015. Y1 - 2015 SP - 1 EP - 4 ER - TY - JOUR A1 - Wolf, Martin R. T1 - Groupware related task design JF - ACM SIGGROUP Bulletin N2 - his report summarizes the results of a workshop on Groupware related task design which took place at the International Conference on Supporting Group Work Group'99, Arizona, from 14 th to 17 th November 1999. The workshop was addressed to people from different viewpoints, backgrounds, and domains: - Researchers dealing with questions of task analysis and task modeling for Groupware application from an academic point of view. They may contribute modelbased design approaches or theoretically oriented work - Practitioners with experience in the design and everyday use of groupware systems. They might refer to the practical side of the topic: "real" tasks, "real" problems, "real" users, etc. Y1 - 2000 U6 - https://doi.org/10.1145/605660.605662 SN - 2372-7403 VL - 21 IS - 2 SP - 5 EP - 8 ER - TY - JOUR A1 - Heuermann, Holger A1 - Stolle, Reinhard A1 - Schiek, Burkhard T1 - Novel Algorithms for FMCW Range Finding with Microwaves. Stolle, R.; Heuermann, H.; Schiek, B. Y1 - 1995 N1 - Conference proceedings / IEEE NTC '95, the Microwave Systems Conference; NTC <1995, Orlando, Fla.> SP - 129 EP - 132 ER - TY - JOUR A1 - Heuermann, Holger A1 - Baumann, F.-M. A1 - Fauth, G. A1 - Albert, M. T1 - Results of Network Analyzer Measurements with Leakage Errors Corrected with the TMS-15-Term Procedure JF - On-Line Moisture Analysis of Raw Coal Y1 - 1994 N1 - 1993 International Symposium on On-Line Analysis of Coal : Vienna ; [proceedings]. SP - 1361 EP - 1364 ER - TY - JOUR A1 - Niemüller, Tim A1 - Lakemeyer, Gerhard A1 - Ferrein, Alexander A1 - Reuter, S. A1 - Ewert, D. A1 - Jeschke, S. A1 - Pensky, D. A1 - Karras, Ulrich T1 - Proposal for advancements to the LLSF in 2014 and beyond Y1 - 2013 SP - Publ. online ER - TY - JOUR A1 - Heuermann, Holger A1 - Schiek, Burkhard T1 - Results of Network Analyzer Measurements with Leakage Errors Corrected with the TMS-15-Term Procedure Y1 - 1994 N1 - 1994 IEEE MTT-S International Microwave Symposium digest : May 23 - 27, 1994, San Diego Convention Center, San Diego, California / H. J. Kuno, ed. SP - 1361 EP - 1364 ER - TY - JOUR A1 - Schopp, Christoph A1 - Britun, Nikolay A1 - Vorac, Jan A1 - Synek, Petr A1 - Snyders, Rony A1 - Heuermann, Holger T1 - Thermal and Optical Study on the Frequency Dependence of an Atmospheric Microwave Argon Plasma Jet JF - IEEE Transactions on Plasma Science Y1 - 2019 SN - 1939-9375 VL - 47 IS - 7 SP - 3176 EP - 3181 PB - IEEE CY - New York ER - TY - JOUR A1 - Ferrein, Alexander A1 - Jacobs, Stefan A1 - Lakemeyer, Gerhard T1 - Controlling Unreal Tournament 2004 Bots with the logic-based action language Golog / Jacobs, Stefan ; Ferrein, Alexander ; Lakemeyer, Gerhard JF - Proceedings of the First AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment (AIIDE). Y1 - 2005 SP - 151 EP - 152 ER - TY - JOUR A1 - Ferrein, Alexander A1 - Steinbauer, Gerald T1 - Looking back on 20 Years of RoboCup JF - KI - Künstliche Intelligenz Y1 - 2016 U6 - https://doi.org/10.1007/s13218-016-0443-y SN - 1610-1987 VL - 30 IS - 3-4 SP - 321 EP - 323 PB - Springer CY - Berlin ER - TY - JOUR A1 - Ferrein, Alexander A1 - Rens, Gavin A1 - Meyer, Thomas A1 - Lakemeyer, Gerhard T1 - A Logic for Specifying Partially Observable Stochastic Domains / Rens, Gavin ; Meyer, Thomas ; Ferrein, Alexander ; Lakemeyer, Gerhard JF - Proceedings of the Ninth International Workshop pn non-Monotonic Reasoning, Action and Change (NRAC`11) Y1 - 2011 N1 - Technical Report RMIT-TR-11-02 SP - 15 EP - 22 ER - TY - JOUR A1 - Heuermann, Holger A1 - Schiek, Burkhard T1 - Scattering Parameter Measurements of Microstrip Devices using the Double-LNN Calibration Technique JF - Conference proceedings : [Palais des Festivals et des Congrès Cannes, France, 5 - 8 September 1994] Y1 - 1994 SN - 0-9518032-5-5 N1 - European Microwave Conference <24, 1994, Cannes> PB - Nexus Business Communications CY - Swanley ER - TY - JOUR A1 - Wolf, Martin R. A1 - Schlick, Christopher A1 - Springer, J. ED - Miyamoto, Hiroyuki T1 - The use of implicit communication mechanisms in desktop-teleconferencing-systems JF - Proceedings of WWDU '97 Tokyo, Fifth International Scientific Conference on Work with Display Units : November 3 - 5, 1997, Tokyo Y1 - 1997 N1 - International Scientific Conference on Work with Display Units ; International Scientific Conference on Work with Display Units ; (5 ; 1997.11.03-05 ; Tokyo) SP - 193 EP - 194 PB - - CY - Tokyo ER - TY - JOUR A1 - Heuermann, Holger A1 - Holtrup, Stephan T1 - Fundamentals and ignition of a microplasma at 2.45 GHZ / Holtrup, Stephan ; Heuermann, Holger JF - European Microwave Conference, 2009 : EuMC 2009 ; Sept. 29, 2009 - Oct. 1, 2009, Rome, Italy ; part of European Microwave Week (EuMW) / sponsored by EuMA, European Microwave Association ... Endorsed by IEEE Y1 - 2009 SN - 978-1-4244-4748-0 N1 - EuMC 2009 SP - 1607 EP - 1609 PB - IEEE CY - Piscataway, NJ ER - TY - JOUR A1 - Haag, S. A1 - Zontar, D. A1 - Schleupen, Josef A1 - Müller, T. A1 - Brecher, C. T1 - Chain of refined perception in self-optimizing assembly of micro-optical systems JF - Journal of sensors and sensor systems N2 - Today, the assembly of laser systems requires a large share of manual operations due to its complexity regarding the optimal alignment of optics. Although the feasibility of automated alignment of laser optics has been shown in research labs, the development effort for the automation of assembly does not meet economic requirements – especially for low-volume laser production. This paper presents a model-based and sensor-integrated assembly execution approach for flexible assembly cells consisting of a macro-positioner covering a large workspace and a compact micromanipulator with camera attached to the positioner. In order to make full use of available models from computer-aided design (CAD) and optical simulation, sensor systems at different levels of accuracy are used for matching perceived information with model data. This approach is named "chain of refined perception", and it allows for automated planning of complex assembly tasks along all major phases of assembly such as collision-free path planning, part feeding, and active and passive alignment. The focus of the paper is put on the in-process image-based metrology and information extraction used for identifying and calibrating local coordinate systems as well as the exploitation of that information for a part feeding process for micro-optics. Results will be presented regarding the processes of automated calibration of the robot camera as well as the local coordinate systems of part feeding area and robot base. Y1 - 2014 U6 - https://doi.org/10.5194/jsss-3-87-2014 SN - 2194-878X VL - 3 IS - 1 SP - 87 EP - 95 PB - Copernicus Publ. CY - Göttingen ER - TY - JOUR A1 - Rietsch, Stefan H. G. A1 - Brunheim, Sascha A1 - Orzada, Stephan A1 - Voelker, Maximilian N. A1 - Maderwald, Stefan A1 - Bitz, Andreas A1 - Gratz, Marcel A1 - Ladd, Mark E. A1 - Quick, Harald H. T1 - Development and evaluation of a 16-channel receive-only RF coil to improve 7T ultra-high field body MRI with focus on the spine JF - Magnetic Resonance in Medicine Y1 - 2019 U6 - https://doi.org/10.1002/mrm.27731 SN - 1522-2594 IS - Early view PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Fagan, Andrew J. A1 - Bitz, Andreas A1 - Björkman-Burtscher, Isabella M. A1 - Collins, Christopher M. A1 - Kimbrell, Vera A1 - Raaijmakers, Alexander J. E. T1 - 7T MR Safety JF - Journal of Magnetic Resonance Imaging (JMRI) Y1 - 2021 U6 - https://doi.org/10.1002/jmri.27319 SN - 1522-2586 VL - 53 IS - 2 SP - 333 EP - 346 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Serror, Martin A1 - Hack, Sacha A1 - Henze, Martin A1 - Schuba, Marko A1 - Wehrle, Klaus T1 - Challenges and Opportunities in Securing the Industrial Internet of Things JF - IEEE Transactions on Industrial Informatics Y1 - 2021 U6 - https://doi.org/10.1109/TII.2020.3023507 SN - 1941-0050 VL - 17 IS - 5 SP - 2985 EP - 2996 PB - IEEE CY - New York ER - TY - JOUR A1 - Fiedler, Thomas M. A1 - Ladd, Mark E. A1 - Clemens, Markus A1 - Bitz, Andreas T1 - Safety of subjects during radiofrequency exposure in ultra-high-field magnetic resonance imaging JF - IEEE Letters on Electromagnetic Compatibility Practice and Applications N2 - Magnetic resonance imaging (MRI) is one of the most important medical imaging techniques. Since the introduction of MRI in the mid-1980s, there has been a continuous trend toward higher static magnetic fields to obtain i.a. a higher signal-to-noise ratio. The step toward ultra-high-field (UHF) MRI at 7 Tesla and higher, however, creates several challenges regarding the homogeneity of the spin excitation RF transmit field and the RF exposure of the subject. In UHF MRI systems, the wavelength of the RF field is in the range of the diameter of the human body, which can result in inhomogeneous spin excitation and local SAR hotspots. To optimize the homogeneity in a region of interest, UHF MRI systems use parallel transmit systems with multiple transmit antennas and time-dependent modulation of the RF signal in the individual transmit channels. Furthermore, SAR increases with increasing field strength, while the SAR limits remain unchanged. Two different approaches to generate the RF transmit field in UHF systems using antenna arrays close and remote to the body are investigated in this letter. Achievable imaging performance is evaluated compared to typical clinical RF transmit systems at lower field strength. The evaluation has been performed under consideration of RF exposure based on local SAR and tissue temperature. Furthermore, results for thermal dose as an alternative RF exposure metric are presented. Y1 - 2020 SN - 2637-6423 U6 - https://doi.org/10.1109/LEMCPA.2020.3029747 VL - 2 IS - 3 SP - 1 EP - 8 PB - IEEE CY - New York, NY ER - TY - JOUR A1 - Hüning, Felix A1 - Backes, Andreas T1 - Direct observation of large Barkhausen jump in thin Vicalloy wires JF - IEEE Magnetics Letters Y1 - 2020 SN - 1949-307X U6 - https://doi.org/10.1109/LMAG.2020.3046411 VL - 11 IS - Art. 2506504 SP - 1 EP - 4 PB - IEEE CY - New York, NY ER - TY - JOUR A1 - Reinhardt, T. A1 - Bitz, Andreas A1 - El Ouardi, A. A1 - Streckert, J. A1 - Sommer, A. A1 - Lerchl, A. A1 - Hansen, V. T1 - Exposure set-ups for in vivo experiments using radial waveguides JF - Radiation Protection Dosimetry Y1 - 2007 U6 - https://doi.org/10.1093/rpd/ncm370 SN - 1742-3406 VL - 124 IS - 1 SP - 21 EP - 26 ER - TY - JOUR A1 - Sommer, Angela M. A1 - Bitz, Andreas A1 - Streckert, Joachim A1 - Hansen, Volkert W. A1 - Lerchl, Alexander T1 - Lymphoma development in mice chronically exposed to UMTS-modulated radiofrequency electromagnetic fields JF - Radiation Research Y1 - 2007 U6 - https://doi.org/10.1667/RR0857.1 SN - 1938-5404 VL - 168 IS - 1 SP - 72 EP - 80 ER - TY - JOUR A1 - Sukhotina, Irina A1 - Streckert, Joachim R. A1 - Bitz, Andreas A1 - Hansen, Volkert W. A1 - Lerchl, Alexander T1 - 1800 MHz electromagnetic field effects on melatonin release from isolated pineal glands JF - Journal of Pineal Research Y1 - 2006 U6 - https://doi.org/10.1111/j.1600-079X.2005.00284.x SN - 1600-079X VL - 40 IS - 1 SP - 86 EP - 91 ER - TY - JOUR A1 - Franke, Helmut A1 - Streckert, Joachim A1 - Bitz, Andreas A1 - Goeke, Johannes A1 - Hansen, Volkert A1 - Ringelstein, E. Bernd A1 - Nattkämper, Heiner A1 - Galle, Hans-Joachim A1 - Stögbauer, Florian T1 - Effects of Universal Mobile Telecommunications System (UMTS) electromagnetic fields on the blood-brain barrier in vitro JF - Radiation Research Y1 - 2005 U6 - https://doi.org/10.1667/RR3424.1 SN - 1938-5404 VL - 164 IS - 3 SP - 258 EP - 269 ER - TY - JOUR A1 - Wissen, M. A1 - Bogdanski, N. A1 - Scheer, H.-C. A1 - Bitz, Andreas A1 - Ahrens, G. A1 - Gruetzner, G. T1 - Implication of the light polarisation for UV curing of pre-patterned resists JF - Microelectronic Engineering Y1 - 2005 U6 - https://doi.org/10.1016/j.mee.2004.12.099 SN - 0167-9317 VL - 78-79 SP - 659 EP - 664 ER - TY - JOUR A1 - Ndoumbè Mbonjo Mbonjo, H. A1 - Streckert, J. A1 - Bitz, Andreas A1 - Hansen, V. A1 - Glasmachers, A. A1 - Gencol, S. A1 - Rozic, D. T1 - Generic UMTS test signal for RF bioelectromagnetic studies JF - Bioelectromagnetics Y1 - 2004 U6 - https://doi.org/10.1002/bem.20007 SN - 1521-186X VL - 25 IS - 6 SP - 415 EP - 425 ER - TY - JOUR A1 - Sommer, Angela M. A1 - Streckert, Joachim A1 - Bitz, Andreas A1 - Hansen, Volkert W. A1 - Lerchl, Alexander T1 - No effects of GSM-modulated 900 MHz electromagnetic fields on survival rate and spontaneous development of lymphoma in female AKR/J mice JF - BMC Cancer Y1 - 2004 U6 - https://doi.org/10.1186/1471-2407-4-77 VL - 77 IS - 4 ER - TY - JOUR A1 - Hansen, Volkert W. A1 - Bitz, Andreas A1 - Streckert, Joachim R. T1 - RF Exposure of Biological Systems in Radial Waveguides JF - IEEE Transactions on Electromagnetic Compatibility Y1 - 1999 U6 - https://doi.org/10.1109/15.809852 SN - 1558-187X VL - 41 IS - 4 SP - 487 EP - 493 ER - TY - JOUR A1 - Orzada, Stephan A1 - Solbach, Klaus A1 - Gratz, Marcel A1 - Brunheim, Sascha A1 - Fiedler, Thomas M. A1 - Johst, Sören A1 - Bitz, Andreas A1 - Shooshtary, Samaneh A1 - Abuelhaija, Asjraf A1 - Voelker, Maximilian N. A1 - Rietsch, Stefan H. G. A1 - Kraff, Oliver A1 - Maderwald, Stefan A1 - Flöser, Martina A1 - Oehmingen, Mark A1 - Quick, Harald H. A1 - Ladd, Mark E. T1 - A 32-channel parallel transmit system add-on for 7T MRI JF - Plos one Y1 - 2019 U6 - https://doi.org/10.1371/journal.pone.0222452 ER - TY - JOUR A1 - Köhler, Klemens T1 - A conflict theory perspective of IT attacks – consequences for IT security education N2 - Cyberspace is "the environment formed by physical and non-physical components to store, modify, and exchange data using computer networks" (NATO CCDCOE). Beyond that, it is an environment where people interact. IT attacks are hostile, non-cooperative interactions that can be described with conflict theory. Applying conflict theory to IT security leads to different objectives for end-user education, requiring different formats like agency-based competence developing games. Y1 - 2020 IS - Preprint ER - TY - JOUR A1 - Leise, Philipp A1 - Eßer, Arved A1 - Eichenlaub, Tobias A1 - Schleiffer, Jean-Eric A1 - Altherr, Lena A1 - Rinderknecht, Stephan A1 - Pelz, Peter F. T1 - Sustainable system design of electric powertrains - comparison of optimization methods JF - Engineering Optimization N2 - The transition within transportation towards battery electric vehicles can lead to a more sustainable future. To account for the development goal ‘climate action’ stated by the United Nations, it is mandatory, within the conceptual design phase, to derive energy-efficient system designs. One barrier is the uncertainty of the driving behaviour within the usage phase. This uncertainty is often addressed by using a stochastic synthesis process to derive representative driving cycles and by using cycle-based optimization. To deal with this uncertainty, a new approach based on a stochastic optimization program is presented. This leads to an optimization model that is solved with an exact solver. It is compared to a system design approach based on driving cycles and a genetic algorithm solver. Both approaches are applied to find efficient electric powertrains with fixed-speed and multi-speed transmissions. Hence, the similarities, differences and respective advantages of each optimization procedure are discussed. KW - Powertrain KW - stochastic optimization KW - global optimization KW - genetic algorithm Y1 - 2021 U6 - https://doi.org/10.1080/0305215X.2021.1928660 SN - 0305-215X PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Altherr, Lena A1 - Ederer, Thorsten A1 - Lorenz, Ulf A1 - Pelz, Peter F. A1 - Pöttgen, Philipp ED - Lübbecke, Marco ED - Koster, Arie ED - Letmathe, Peter ED - Madlener, Reihard ED - Peis, Britta ED - Walther, Grit T1 - Experimental validation of an enhanced system synthesis approach JF - Operations Research Proceedings 2014 N2 - Planning the layout and operation of a technical system is a common task for an engineer. Typically, the workflow is divided into consecutive stages: First, the engineer designs the layout of the system, with the help of his experience or of heuristic methods. Secondly, he finds a control strategy which is often optimized by simulation. This usually results in a good operating of an unquestioned sys- tem topology. In contrast, we apply Operations Research (OR) methods to find a cost-optimal solution for both stages simultaneously via mixed integer program- ming (MILP). Technical Operations Research (TOR) allows one to find a provable global optimal solution within the model formulation. However, the modeling error due to the abstraction of physical reality remains unknown. We address this ubiq- uitous problem of OR methods by comparing our computational results with mea- surements in a test rig. For a practical test case we compute a topology and control strategy via MILP and verify that the objectives are met up to a deviation of 8.7%. Y1 - 2014 SN - 978-3-319-28695-2 U6 - https://doi.org/10.1007/978-3-319-28697-6_1 PB - Springer CY - Basel ER - TY - JOUR A1 - Sun, Hui A1 - Altherr, Lena A1 - Pei, Ji A1 - Pelz, Peter F. A1 - Yuan, Shouqi T1 - Optimal booster station design and operation under uncertain load JF - Applied Mechanics and Materials N2 - Given industrial applications, the costs for the operation and maintenance of a pump system typically far exceed its purchase price. For finding an optimal pump configuration which minimizes not only investment, but life-cycle costs, methods like Technical Operations Research which is based on Mixed-Integer Programming can be applied. However, during the planning phase, the designer is often faced with uncertain input data, e.g. future load demands can only be estimated. In this work, we deal with this uncertainty by developing a chance-constrained two-stage (CCTS) stochastic program. The design and operation of a booster station working under uncertain load demand are optimized to minimize total cost including purchase price, operation cost incurred by energy consumption and penalty cost resulting from water shortage. We find optimized system layouts using a sample average approximation (SAA) algorithm, and analyze the results for different risk levels of water shortage. By adjusting the risk level, the costs and performance range of the system can be balanced, and thus the system’s resilience can be engineered KW - Stochastic Programming KW - Chance Constraint KW - Engineering Application KW - Pump System KW - Water Distribution Y1 - 2018 U6 - https://doi.org/10.4028/www.scientific.net/AMM.885.102 SN - 1662-7482 VL - 885 SP - 102 EP - 115 PB - Trans Tech Publications CY - Bäch ER - TY - JOUR A1 - Altherr, Lena A1 - Brötz, Nicolas A1 - Dietrich, Ingo A1 - Gally, Tristan A1 - Geßner, Felix A1 - Kloberdanz, Hermann A1 - Leise, Philipp A1 - Pelz, Peter Franz A1 - Schlemmer, Pia A1 - Schmitt, Andreas T1 - Resilience in mechanical engineering - a concept for controlling uncertainty during design, production and usage phase of load-carrying structures JF - Applied Mechanics and Materials N2 - Resilience as a concept has found its way into different disciplines to describe the ability of an individual or system to withstand and adapt to changes in its environment. In this paper, we provide an overview of the concept in different communities and extend it to the area of mechanical engineering. Furthermore, we present metrics to measure resilience in technical systems and illustrate them by applying them to load-carrying structures. By giving application examples from the Collaborative Research Centre (CRC) 805, we show how the concept of resilience can be used to control uncertainty during different stages of product life. Y1 - 2018 SN - 1662-7482 U6 - https://doi.org/10.4028/www.scientific.net/AMM.885.187 VL - 885 SP - 187 EP - 198 PB - Trans Tech Publications CY - Bäch ER - TY - JOUR A1 - Rausch, Lea A1 - Friesen, John A1 - Altherr, Lena A1 - Meck, Marvin A1 - Pelz, Peter F. T1 - A holistic concept to design optimal water supply infrastructures for informal settlements using remote sensing data JF - Remote Sensing N2 - Ensuring access to water and sanitation for all is Goal No. 6 of the 17 UN Sustainability Development Goals to transform our world. As one step towards this goal, we present an approach that leverages remote sensing data to plan optimal water supply networks for informal urban settlements. The concept focuses on slums within large urban areas, which are often characterized by a lack of an appropriate water supply. We apply methods of mathematical optimization aiming to find a network describing the optimal supply infrastructure. Hereby, we choose between different decentral and central approaches combining supply by motorized vehicles with supply by pipe systems. For the purposes of illustration, we apply the approach to two small slum clusters in Dhaka and Dar es Salaam. We show our optimization results, which represent the lowest cost water supply systems possible. Additionally, we compare the optimal solutions of the two clusters (also for varying input parameters, such as population densities and slum size development over time) and describe how the result of the optimization depends on the entered remote sensing data. KW - water supply design KW - mathematical optimization KW - slum classification KW - remote sensing Y1 - 2018 SN - 2072-4292 U6 - https://doi.org/10.3390/rs10020216 VL - 10 IS - 2 SP - 1 EP - 23 PB - MDPI CY - Basel ER - TY - JOUR A1 - Altherr, Lena A1 - Joggerst, Laura A1 - Leise, Philipp A1 - Pfetsch, Marc E. A1 - Schmitt, Andreas A1 - Wendt, Janine T1 - On obligations in the development process of resilient systems with algorithmic design methods JF - Applied Mechanics and Materials N2 - Advanced computational methods are needed both for the design of large systems and to compute high accuracy solutions. Such methods are efficient in computation, but the validation of results is very complex, and highly skilled auditors are needed to verify them. We investigate legal questions concerning obligations in the development phase, especially for technical systems developed using advanced methods. In particular, we consider methods of resilient and robust optimization. With these techniques, high performance solutions can be found, despite a high variety of input parameters. However, given the novelty of these methods, it is uncertain whether legal obligations are being met. The aim of this paper is to discuss if and how the choice of a specific computational method affects the developer’s product liability. The review of legal obligations in this paper is based on German law and focuses on the requirements that must be met during the design and development process. KW - legal obligations KW - product liability KW - design of technical systems KW - optimization KW - resilience Y1 - 2018 SN - 1662-7482 U6 - https://doi.org/10.4028/www.scientific.net/AMM.885.240 VL - 885 IS - 885 SP - 240 EP - 252 PB - Trans Tech Publications CY - Bäch ER - TY - JOUR A1 - Pöttgen, Philipp A1 - Ederer, Thorsten A1 - Altherr, Lena A1 - Lorenz, Ulf A1 - Pelz, Peter F. T1 - Examination and optimization of a heating circuit for energy-efficient buildings JF - Energy Technology N2 - The conference center darmstadtium in Darmstadt is a prominent example of energy efficient buildings. Its heating system consists of different source and consumer circuits connected by a Zortström reservoir. Our goal was to reduce the energy costs of the system as much as possible. Therefore, we analyzed its supply circuits. The first step towards optimization is a complete examination of the system: 1) Compilation of an object list for the system, 2) collection of the characteristic curves of the components, and 3) measurement of the load profiles of the heat and volume-flow demand. Instead of modifying the system manually and testing the solution by simulation, the second step was the creation of a global optimization program. The objective was to minimize the total energy costs for one year. We compare two different topologies and show opportunities for significant savings. KW - energy transfer KW - heating system KW - programming KW - system optimization KW - technical operations research Y1 - 2015 SN - 2194-4296 U6 - https://doi.org/10.1002/ente.201500252 VL - 4 IS - 1 SP - 136 EP - 144 PB - WILEY-VCH Verlag CY - Weinheim ER - TY - JOUR A1 - Altherr, Lena A1 - Ederer, Thorsten A1 - Pöttgen, Philipp A1 - Lorenz, Ulf A1 - Pelz, Peter F. ED - Pelz, Peter F. ED - Groche, Peter T1 - Multicriterial optimization of technical systems considering multiple load and availability scenarios JF - Applied Mechanics and Materials N2 - Cheap does not imply cost-effective -- this is rule number one of zeitgeisty system design. The initial investment accounts only for a small portion of the lifecycle costs of a technical system. In fluid systems, about ninety percent of the total costs are caused by other factors like power consumption and maintenance. With modern optimization methods, it is already possible to plan an optimal technical system considering multiple objectives. In this paper, we focus on an often neglected contribution to the lifecycle costs: downtime costs due to spontaneous failures. Consequently, availability becomes an issue. KW - sustainability KW - availability KW - energy efficiency KW - mixed-integer linear programming KW - system synthesis Y1 - 2015 SN - 1660-9336 U6 - https://doi.org/10.4028/www.scientific.net/AMM.807.247 VL - 807 SP - 247 EP - 256 ER - TY - JOUR A1 - Czarnecki, Christian A1 - Spiliopoulou, Myra T1 - A holistic framework for the implementation of a next generation network JF - International Journal of Business Information Systems N2 - As the potential of a next generation network (NGN) is recognised, telecommunication companies consider switching to it. Although the implementation of an NGN seems to be merely a modification of the network infrastructure, it may trigger or require changes in the whole company, because it builds upon the separation between service and transport, a flexible bundling of services to products and the streamlining of the IT infrastructure. We propose a holistic framework, structured into the layers ‘strategy’, ‘processes’ and ‘information systems’ and incorporate into each layer all concepts necessary for the implementation of an NGN, as well as the alignment of these concepts. As a first proof-of-concept for our framework we have performed a case study on the introduction of NGN in a large telecommunication company; we show that our framework captures all topics that are affected by an NGN implementation. KW - next generation network KW - telecommunication KW - NGN KW - IP-based networks KW - product bundling Y1 - 2012 U6 - https://doi.org/10.1504/IJBIS.2012.046291 SN - 1746-0972 VL - 9 IS - 4 SP - 385 EP - 401 PB - Inderscience Enterprises CY - Olney, Bucks ER -