@article{KrauseMeurerKlee1988, author = {Krause, Gregor and Meurer, D. and Klee, D.}, title = {Space Charge Formation Related to the Morphology of Polymers}, series = {ISE 6 : 6th International symposium on electrets : Papers}, journal = {ISE 6 : 6th International symposium on electrets : Papers}, publisher = {IEEE}, address = {Piscataway, NY}, pages = {XIX, 688 S. : graph. Darst.}, year = {1988}, language = {en} } @article{KrauseMeurerKlee1989, author = {Krause, Gregor and Meurer, D. and Klee, D.}, title = {Space charge formation related to the morphology of polymers}, series = {IEEE Transaction on Electrical Insulation. Vol. 24 (1989), H. No. 3}, journal = {IEEE Transaction on Electrical Insulation. Vol. 24 (1989), H. No. 3}, pages = {215 -- 222}, year = {1989}, language = {en} } @article{KrauseMoellerMeurer1989, author = {Krause, Gregor and M{\"o}ller, K. and Meurer, D.}, title = {Dielectric phenomena in semicrystalline polymers}, series = {IEEE Transaction on Electrical Insulation. Vol. 24 (1989), H. No. 2}, journal = {IEEE Transaction on Electrical Insulation. Vol. 24 (1989), H. No. 2}, pages = {215 -- 222}, year = {1989}, language = {en} } @article{KrauseNeubertPietsch1990, author = {Krause, Gregor and Neubert, R. and Pietsch, R.}, title = {Investigations of Electrical Aging in Polymers under High AC-Field Strength}, series = {1990 annual report : October 28 - October 31, 1990 / sponsored by the IEEE Dielectrics and Electrical Insulation Society}, journal = {1990 annual report : October 28 - October 31, 1990 / sponsored by the IEEE Dielectrics and Electrical Insulation Society}, publisher = {IEEE Service Center}, address = {Piscataway, N.J}, pages = {716 S : Ill., graph. Darst.}, year = {1990}, language = {en} } @article{KrauseRodriguezStopicetal.2007, author = {Krause, Gregor and Rodriguez, Jackson and Stopic, Srecko and Friedrich, Bernd}, title = {Feasibility assessment of electrocoagulation towards a new sustainable wastewater treatment / Rodriguez, Jackson ; Stopic, Srecko ; Krause Gregor ; Friedrich, Bernd}, series = {Environmental Science and Pollution Research. 14 (2007), H. 7}, journal = {Environmental Science and Pollution Research. 14 (2007), H. 7}, isbn = {0944-1344}, pages = {477 -- 482}, year = {2007}, language = {en} } @article{KrauseSchuppeSaureetal.1988, author = {Krause, Gregor and Schuppe, W.D. and Saure, M. and Andress, H.}, title = {Sensitive Analytical and Physical Methods for Diagnosis of Variations in Polyolefin Plaques and Cable Insulations / W.D. Schuppe, M. Saure, H. Andress, K. M{\"o}ller, D. Meurer, G. Krause}, series = {Proceedings of the 32nd session : 28th August - 3rd September.}, journal = {Proceedings of the 32nd session : 28th August - 3rd September.}, year = {1988}, language = {en} } @inproceedings{KrueckelNoldenFerreinetal.2015, author = {Kr{\"u}ckel, Kai and Nolden, Florian and Ferrein, Alexander and Scholl, Ingrid}, title = {Intuitive visual teleoperation for UGVs using free-look augmented reality displays}, series = {2015 IEEE International Conference on Robotics and Automation (ICRA), Seattle, WA}, booktitle = {2015 IEEE International Conference on Robotics and Automation (ICRA), Seattle, WA}, doi = {10.1109/ICRA.2015.7139809}, pages = {4412 -- 4417}, year = {2015}, language = {en} } @article{Koehler2020, author = {K{\"o}hler, Klemens}, title = {A conflict theory perspective of IT attacks - consequences for IT security education}, number = {Preprint}, year = {2020}, abstract = {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.}, language = {en} } @article{KoehlerRoepkeWolf2021, author = {K{\"o}hler, Klemens and R{\"o}pke, Ren{\´e} and Wolf, Martin}, title = {Through a mirror darkly - On the obscurity of teaching goals in game-based learning in IT security}, series = {ISAGA 2019: Simulation Gaming Through Times and Disciplines}, journal = {ISAGA 2019: Simulation Gaming Through Times and Disciplines}, publisher = {Springer}, address = {Cham}, doi = {10.1007/978-3-030-72132-9_6}, pages = {61 -- 73}, year = {2021}, abstract = {Teachers and instructors use very specific language communicating teaching goals. The most widely used frameworks of common reference are the Bloom's Taxonomy and the Revised Bloom's Taxonomy. The latter provides distinction of 209 different teaching goals which are connected to methods. In Competence Developing Games (CDGs - serious games to convey knowledge) and in IT security education, a two- or three level typology exists, reducing possible learning outcomes to awareness, training, and education. This study explores whether this much simpler framework succeeds in achieving the same range of learning outcomes. Method wise a keyword analysis was conducted. The results were threefold: 1. The words used to describe teaching goals in CDGs on IT security education do not reflect the whole range of learning outcomes. 2. The word choice is nevertheless different from common language, indicating an intentional use of language. 3. IT security CDGs use different sets of terms to describe learning outcomes, depending on whether they are awareness, training, or education games. The interpretation of the findings is that the reduction to just three types of CDGs reduces the capacity to communicate and think about learning outcomes and consequently reduces the outcomes that are intentionally achieved.}, language = {en} } @inproceedings{KoellenspergerBragardPlumetal.2007, author = {K{\"o}llensperger, P. and Bragard, Michael and Plum, T. and De Doncker, R. W.}, title = {The dual GCT : a new high-power device using optimized GCT technology}, series = {Conference record of the 2007 IEEE Industry Applications Conference : 42. IAS annual meeting ; September 23 - 27, 2007, New Orleans, Louisiana, USA}, booktitle = {Conference record of the 2007 IEEE Industry Applications Conference : 42. IAS annual meeting ; September 23 - 27, 2007, New Orleans, Louisiana, USA}, publisher = {IEEE Operations Center}, address = {Piscataway, NJ}, isbn = {978-1-4244-1260-0 (Online)}, doi = {10.1109/07IAS.2007.76}, pages = {358 -- 365}, year = {2007}, language = {en} } @article{KoellenspergerBragardPlumetal.2009, author = {K{\"o}llensperger, P. and Bragard, Michael and Plum, T. and De Doncker, R. W.}, title = {The dual GCT : new high-power device using optimized GCT technology}, series = {IEEE transactions on industry applications}, volume = {45}, journal = {IEEE transactions on industry applications}, number = {5}, issn = {0093-9994}, doi = {10.1109/TIA.2009.2027364}, pages = {1754 -- 1762}, year = {2009}, language = {en} } @inproceedings{KoenigVoelkerWolf2018, author = {K{\"o}nig, Johannes Alexander and V{\"o}lker, Veronika and Wolf, Martin}, title = {The user-focused storybuilding framework for competence developing games - a design-framework considering the basics of an educational game's story}, series = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, booktitle = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, isbn = {978-1-61208-616-3}, pages = {98 -- 106}, year = {2018}, abstract = {During the development of a Competence Developing Game's (CDG) story it is indispensable to understand the target audience. Thereby, CDGs stories represent more than just the plot. The Story is about the Setting, the Characters and the Plot. As a toolkit to support the development of such a story, this paper introduces the UserFocused Storybuilding (short UFoS) Framework for CDGs. The Framework and its utilization will be explained, followed by a description of its development and derivation, including an empirical study. In addition, to simplify the Framework use regarding the CDG's target audience, a new concept of Nine Psychographic Player Types will be explained. This concept of Player Types provides an approach to handle the differences in between players during the UFoS Framework use. Thereby, this article presents a unique approach to the development of target group-differentiated CDGs stories.}, language = {en} } @inproceedings{KoenigWolf2016, author = {K{\"o}nig, Johannes Alexander and Wolf, Martin}, title = {The pyramid assessment framework for 'competence developing games'}, series = {Communications in Computer and Information Science}, volume = {618}, booktitle = {Communications in Computer and Information Science}, editor = {Stephanidis, C.}, publisher = {Springer}, isbn = {978-331940541-4}, issn = {1865-0929}, doi = {10.1007/978-3-319-40542-1_37}, pages = {232 -- 237}, year = {2016}, language = {en} } @article{KoenigWolf2018, author = {K{\"o}nig, Johannes Alexander and Wolf, Martin}, title = {GHOST: An Evaluated Competence Developing Game for Cybersecurity Awareness Training}, series = {International Journal on Advances in Security}, volume = {11}, journal = {International Journal on Advances in Security}, number = {3 \& 4}, publisher = {IARIA Journals}, issn = {1942-2636}, pages = {274 -- 287}, year = {2018}, abstract = {To train end users how to interact with digital systems is indispensable to ensure a strong computer security. 'Competence Developing Game'-based approaches are particularly suitable for this purpose because of their motivation-and simulation-aspects. In this paper the Competence Developing Game 'GHOST' for cybersecurity awareness trainings and its underlying patterns are described. Accordingly, requirements for an 'Competence Developing Game' based training are discussed. Based on these requirements it is shown how a game can fulfill these requirements. A supplementary game interaction design and a corresponding evaluation study is shown. The combination of training requirements and interaction design is used to create a 'Competence Developing Game'-based training concept. A part of these concept is implemented into a playable prototype that serves around one hour of play respectively training time. This prototype is used to perform an evaluation of the game and training aspects of the awareness training. Thereby, the quality of the game aspect and the effectiveness of the training aspect are shown.}, language = {en} } @inproceedings{KoenigWolf2018, author = {K{\"o}nig, Johannes Alexander and Wolf, Martin}, title = {Cybersecurity awareness training provided by the competence developing game GHOST}, series = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, booktitle = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, isbn = {978-1-61208-616-3}, pages = {81 -- 87}, year = {2018}, abstract = {This paper introduces a Competence Developing Game (CDG) for the purpose of a cybersecurity awareness training for businesses. The target audience will be discussed in detail to understand their requirements. It will be explained why and how a mix of business simulation and serious game meets these stakeholder requirements. It will be shown that a tablet and touchscreen based approach is the most suitable solution. In addition, an empirical study will be briefly presented. The study was carried out to examine how an interaction system for a 3D-tablet based CDG has to be designed, to be manageable for non-game experienced employees. Furthermore, it will be explained which serious content is necessary for a Cybersecurity awareness training CDG and how this content is wrapped in the game}, language = {en} } @incollection{KuemmellHillgaertner2015, author = {K{\"u}mmell, Steffen and Hillg{\"a}rtner, Michael}, title = {Inductive charging comfortable and nonvisible charging stations for urbanised areas}, series = {E-Mobility in Europe : trends and good practice}, booktitle = {E-Mobility in Europe : trends and good practice}, publisher = {Springer}, address = {Cham [u.a.]}, isbn = {978-3-319-13193-1}, doi = {10.1007/978-3-319-13194-8_16}, pages = {297 -- 309}, year = {2015}, abstract = {For a wide acceptance of E-Mobility, a well-developed charging infrastructure is needed. Conductive charging stations, which are today's state of the art, are of limited suitability for urbanised areas, since they cause a significant diversification in townscape. Furthermore, they might be destroyed by vandalism. Besides for those urbanistic reasons, inductive charging stations are a much more comfortable alternative, especially in urbanised areas. The usage of conductive charging stations requires more or less bulky charging cables. The handling of those standardised charging cables, especially during poor weather conditions, might cause inconvenience, such as dirty clothing etc. Wireless charging does not require visible and vandalism vulnerable charge sticks. No wired connection between charging station and vehicle is needed, which enable the placement below the surface of parking spaces or other points of interest. Inductive charging seems to be the optimal alternative for E-Mobility, as a high power transfer can be realised with a manageable technical and financial effort. For a well-accepted and working public charging infrastructure in urbanised areas it is essential that the infrastructure fits the vehicles' needs. Hence, a well-adjusted standardisation of the charging infrastructure is essential. This is carried out by several IEC (International Electrotechnical Commission) and national standardisation committees. To ensure an optimised technical solution for future's inductive charging infrastructures, several field tests had been carried out and are planned in near future.}, language = {en} } @inproceedings{KueppersSchubaNeugebaueretal.2023, author = {K{\"u}ppers, Malte and Schuba, Marko and Neugebauer, Georg and H{\"o}ner, Tim and Hack, Sacha}, title = {Security analysis of the KNX smart building protocol}, series = {ARES '23: Proceedings of the 18th International Conference on Availability, Reliability and Security}, booktitle = {ARES '23: Proceedings of the 18th International Conference on Availability, Reliability and Security}, publisher = {ACM}, doi = {10.1145/3600160.3605167}, pages = {1 -- 7}, year = {2023}, abstract = {KNX is a protocol for smart building automation, e.g., for automated heating, air conditioning, or lighting. This paper analyses and evaluates state-of-the-art KNX devices from manufacturers Merten, Gira and Siemens with respect to security. On the one hand, it is investigated if publicly known vulnerabilities like insecure storage of passwords in software, unencrypted communication, or denialof-service attacks, can be reproduced in new devices. On the other hand, the security is analyzed in general, leading to the discovery of a previously unknown and high risk vulnerability related to so-called BCU (authentication) keys.}, language = {en} } @article{LagemaatBreukelsVosetal.2016, author = {Lagemaat, Miriam W. and Breukels, Vincent and Vos, Eline K. and B., Adam and Uden, Mark J. van and Orzada, Stephan and Bitz, Andreas and Maas, Marnix C. and Scheenen, Tom W. J.}, title = {¹H MR spectroscopic imaging of the prostate at 7T using spectral-spatial pulses}, series = {Magnetic Resonance in Medicine}, volume = {75}, journal = {Magnetic Resonance in Medicine}, number = {3}, publisher = {International Society for Magnetic Resonance in Medicine}, issn = {1522-2594}, doi = {10.1002/mrm.25569}, pages = {933 -- 945}, year = {2016}, abstract = {Purpose To assess the feasibility of prostate ¹H MR spectroscopic imaging (MRSI) using low-power spectral-spatial (SPSP) pulses at 7T, exploiting accurate spectral selection and spatial selectivity simultaneously. Methods A double spin-echo sequence was equipped with SPSP refocusing pulses with a spectral selectivity of 1 ppm. Three-dimensional prostate ¹H-MRSI at 7T was performed with the SPSP-MRSI sequence using an 8-channel transmit array coil and an endorectal receive coil in three patients with prostate cancer and in one healthy subject. No additional water or lipid suppression pulses were used. Results Prostate ¹H-MRSI could be obtained well within specific absorption rate (SAR) limits in a clinically feasible time (10 min). Next to the common citrate signals, the prostate spectra exhibited high spermine signals concealing creatine and sometimes also choline. Residual lipid signals were observed at the edges of the prostate because of limitations in spectral and spatial selectivity. Conclusion It is possible to perform prostate ¹H-MRSI at 7T with a SPSP-MRSI sequence while using separate transmit and receive coils. This low-SAR MRSI concept provides the opportunity to increase spatial resolution of MRSI within reasonable scan times.}, language = {en} } @article{LagemaatMaasVosetal.2015, author = {Lagemaat, Miriam W. and Maas, Marnix C. and Vos, Eline K. and Bitz, Andreas and Orzada, Stephan and Weiland, Elisabeth and Uden, Mark J. van and Kobus, Thiele and Heerschap, Arend and Scheenen, Tom W. J.}, title = {(31) P MR spectroscopic imaging of the human prostate at 7 T: T1 relaxation times, Nuclear Overhauser Effect, and spectral characterization}, series = {Magnetic Resonance in Medicine}, volume = {73}, journal = {Magnetic Resonance in Medicine}, number = {3}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.25209}, pages = {909 -- 920}, year = {2015}, language = {en} } @article{LagemaatVosMaasetal.2014, author = {Lagemaat, Miriam W. and Vos, Eline K. and Maas, Marnix C. and Bitz, Andreas and Orzada, Stephan and Uden, Mark J. van and Kobus, Thiele and Heerschap, Arend and Scheenen, Tom W. J.}, title = {Phosphorus magnetic resonance spectroscopic imaging at 7 T in patients with prostate cancer}, series = {Investigative Radiology}, volume = {49}, journal = {Investigative Radiology}, number = {5}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia, Pa.}, issn = {1536-0210}, doi = {10.1097/RLI.0000000000000012}, pages = {363 -- 372}, year = {2014}, abstract = {Objectives The aim of this study was to identify characteristics of phosphorus (³¹P) spectra of the human prostate and to investigate changes of individual phospholipid metabolites in prostate cancer through in vivo ³¹P magnetic resonance spectroscopic imaging (MRSI) at 7 T. Materials and Methods In this institutional review board-approved study, 15 patients with biopsy-proven prostate cancer underwent T₂-weighted magnetic resonance imaging and 3-dimensional ³¹P MRSI at 7 T. Voxels were selected at the tumor location, in normal-appearing peripheral zone tissue, normal-appearing transition zone tissue, and in the base of the prostate close to the seminal vesicles. Phosphorus metabolite ratios were determined and compared between tissue types. Results Signals of phosphoethanolamine (PE) and phosphocholine (PC) were present and well resolved in most ³¹P spectra in the prostate. Glycerophosphocholine signals were observable in 43\% of the voxels in malignant tissue, but in only 10\% of the voxels in normal-appearing tissue away from the seminal vesicles. In many spectra, independent of tissue type, 2 peaks resonated in the chemical shift range of inorganic phosphate, possibly representing 2 separate pH compartments. The PC/PE ratio in the seminal vesicles was highly elevated compared with the prostate in 5 patients. A considerable overlap of ³¹P metabolite ratios was found between prostate cancer and normal-appearing prostate tissue, preventing direct discrimination of these tissues. The only 2 patients with high Gleason scores tumors (≥4+5) presented with high PC and glycerophosphocholine levels in their cancer lesions. Conclusions Phosphorus MRSI at 7 T shows distinct features of phospholipid metabolites in the prostate gland and its surrounding structures. In this exploratory study, no differences in ³¹P metabolite ratios were observed between prostate cancer and normal-appearing prostate tissue possibly because of the partial volume effects of small tumor foci in large MRSI voxels.}, language = {en} } @inproceedings{LandAGligorevic2004, author = {Land, Ingmar and A., Peter and Gligorevic, Snjezana}, title = {Computation of symbol-wise mutual information in transmission systems with logAPP decoders and application to EXIT charts}, series = {5th International ITG Conference on Source and Channel Coding (SCC) : January 14 - 16, 2004, Erlangen ; conference record. (ITG-Fachbericht ; 181)}, booktitle = {5th International ITG Conference on Source and Channel Coding (SCC) : January 14 - 16, 2004, Erlangen ; conference record. (ITG-Fachbericht ; 181)}, publisher = {VDE-Verl.}, address = {Berlin [u.a.]}, organization = {International Conference Source and Channel Coding <5, 2004, Erlangen>}, isbn = {3-8007-2802-8}, pages = {195 -- 202}, year = {2004}, language = {en} } @article{LeingartnerMaurerFerreinetal.2016, author = {Leingartner, Max and Maurer, Johannes and Ferrein, Alexander and Steinbauer, Gerald}, title = {Evaluation of Sensors and Mapping Approaches for Disasters in Tunnels}, series = {Journal of Field Robotics}, volume = {33}, journal = {Journal of Field Robotics}, number = {8}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1556-4967}, doi = {10.1002/rob.21611}, pages = {1037 -- 1057}, year = {2016}, abstract = {Ground or aerial robots equipped with advanced sensing technologies, such as three-dimensional laser scanners and advanced mapping algorithms, are deemed useful as a supporting technology for first responders. A great deal of excellent research in the field exists, but practical applications at real disaster sites are scarce. Many projects concentrate on equipping robots with advanced capabilities, such as autonomous exploration or object manipulation. In spite of this, realistic application areas for such robots are limited to teleoperated reconnaissance or search. In this paper, we investigate how well state-of-the-art and off-the-shelf components and algorithms are suited for reconnaissance in current disaster-relief scenarios. The basic idea is to make use of some of the most common sensors and deploy some widely used algorithms in a disaster situation, and to evaluate how well the components work for these scenarios. We acquired the sensor data from two field experiments, one from a disaster-relief operation in a motorway tunnel, and one from a mapping experiment in a partly closed down motorway tunnel. Based on these data, which we make publicly available, we evaluate state-of-the-art and off-the-shelf mapping approaches. In our analysis, we integrate opinions and replies from first responders as well as from some algorithm developers on the usefulness of the data and the limitations of the deployed approaches, respectively. We discuss the lessons we learned during the two missions. These lessons are interesting for the community working in similar areas of urban search and rescue, particularly reconnaissance and search.}, language = {en} } @inproceedings{LeingartnerMaurerSteinbaueretal.2013, author = {Leingartner, Max and Maurer, Johannes and Steinbauer, Gerald and Ferrein, Alexander}, title = {Evaluation of sensors and mapping approaches for disasters in tunnels}, series = {IEEE International Symposium on Safety, Security, and Rescue Robotics : SSRR : 21-26 Oct. 2013, Linkoping, Sweden}, booktitle = {IEEE International Symposium on Safety, Security, and Rescue Robotics : SSRR : 21-26 Oct. 2013, Linkoping, Sweden}, organization = {Institute of Electrical and Electronics Engineers}, isbn = {978-1-4799-0879-0}, pages = {1 -- 7}, year = {2013}, language = {en} } @inproceedings{LeiseAltherr2018, author = {Leise, Philipp and Altherr, Lena}, title = {Optimizing the design and control of decentralized water supply systems - a case-study of a hotel building}, series = {EngOpt 2018 Proceedings of the 6th International Conference on Engineering Optimization}, booktitle = {EngOpt 2018 Proceedings of the 6th International Conference on Engineering Optimization}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-97773-7}, doi = {10.1007/978-3-319-97773-7_107}, pages = {1241 -- 1252}, year = {2018}, abstract = {To increase pressure to supply all floors of high buildings with water, booster stations, normally consisting of several parallel pumps in the basement, are used. In this work, we demonstrate the potential of a decentralized pump topology regarding energy savings in water supply systems of skyscrapers. We present an approach, based on Mixed-Integer Nonlinear Programming, that allows to choose an optimal network topology and optimal pumps from a predefined construction kit comprising different pump types. Using domain-specific scaling laws and Latin Hypercube Sampling, we generate different input sets of pump types and compare their impact on the efficiency and cost of the total system design. As a realistic application example, we consider a hotel building with 325 rooms, 12 floors and up to four pressure zones.}, language = {en} } @incollection{LeiseAltherr2021, author = {Leise, Philipp and Altherr, Lena}, title = {Experimental evaluation of resilience metrics in a fluid system}, series = {Mastering Uncertainty in Mechanical Engineering}, booktitle = {Mastering Uncertainty in Mechanical Engineering}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-78356-3}, pages = {442 -- 447}, year = {2021}, language = {en} } @inproceedings{LeiseAltherrPelz2018, author = {Leise, Philipp and Altherr, Lena and Pelz, Peter F.}, title = {Technical Operations Research (TOR) - Algorithms, not Engineers, Design Optimal Energy Efficient and Resilient Cooling Systems}, series = {FAN2018 - Proceedings of the International Conference on Fan Noise, Aerodynamics, Applications and Systems}, booktitle = {FAN2018 - Proceedings of the International Conference on Fan Noise, Aerodynamics, Applications and Systems}, pages = {1 -- 12}, year = {2018}, abstract = {The overall energy efficiency of ventilation systems can be improved by considering not only single components, but by considering as well the interplay between every part of the system. With the help of the method "TOR" ("Technical Operations Research"), which was developed at the Chair of Fluid Systems at TU Darmstadt, it is possible to improve the energy efficiency of the whole system by considering all possible design choices programmatically. We show the ability of this systematic design approach with a ventilation system for buildings as a use case example. Based on a Mixed-Integer Nonlinear Program (MINLP) we model the ventilation system. We use binary variables to model the selection of different pipe diameters. Multiple fans are model with the help of scaling laws. The whole system is represented by a graph, where the edges represent the pipes and fans and the nodes represents the source of air for cooling and the sinks, that have to be cooled. At the beginning, the human designer chooses a construction kit of different suitable fans and pipes of different diameters and different load cases. These boundary conditions define a variety of different possible system topologies. It is not possible to consider all topologies by hand. With the help of state of the art solvers, on the other side, it is possible to solve this MINLP. Next to this, we also consider the effects of malfunctions in different components. Therefore, we show a first approach to measure the resilience of the shown example use case. Further, we compare the conventional approach with designs that are more resilient. These more resilient designs are derived by extending the before mentioned model with further constraints, that consider explicitly the resilience of the overall system. We show that it is possible to design resilient systems with this method already in the early design stage and compare the energy efficiency and resilience of these different system designs.}, language = {en} } @incollection{LeiseAltherrPelz2018, author = {Leise, Philipp and Altherr, Lena and Pelz, Peter F.}, title = {Energy-Efficient design of a water supply system for skyscrapers by mixed-integer nonlinear programming}, series = {Operations Research Proceedings 2017}, booktitle = {Operations Research Proceedings 2017}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-89919-0}, doi = {10.1007/978-3-319-89920-6_63}, year = {2018}, abstract = {The energy-efficiency of technical systems can be improved by a systematic design approach. Technical Operations Research (TOR) employs methods known from Operations Research to find a global optimal layout and operation strategy of technical systems. We show the practical usage of this approach by the systematic design of a decentralized water supply system for skyscrapers. All possible network options and operation strategies are modeled by a Mixed-Integer Nonlinear Program. We present the optimal system found by our approach and highlight the energy savings compared to a conventional system design.}, language = {en} } @incollection{LeiseAltherrSimonetal.2019, author = {Leise, Philipp and Altherr, Lena and Simon, Nicolai and Pelz, Peter F.}, title = {Finding global-optimal gearbox designs for battery electric vehicles}, series = {Optimization of complex systems - theory, models, algorithms and applications : WCGO 2019}, booktitle = {Optimization of complex systems - theory, models, algorithms and applications : WCGO 2019}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-21802-7}, doi = {10.1007/978-3-030-21803-4_91}, pages = {916 -- 925}, year = {2019}, abstract = {In order to maximize the possible travel distance of battery electric vehicles with one battery charge, it is mandatory to adjust all components of the powertrain carefully to each other. While current vehicle designs mostly simplify the powertrain rigorously and use an electric motor in combination with a gearbox with only one fixed transmission ratio, the use of multi-gear systems has great potential. First, a multi-speed system is able to improve the overall energy efficiency. Secondly, it is able to reduce the maximum momentum and therefore to reduce the maximum current provided by the traction battery, which results in a longer battery lifetime. In this paper, we present a systematic way to generate multi-gear gearbox designs that—combined with a certain electric motor—lead to the most efficient fulfillment of predefined load scenarios and are at the same time robust to uncertainties in the load. Therefore, we model the electric motor and the gearbox within a Mixed-Integer Nonlinear Program, and optimize the efficiency of the mechanical parts of the powertrain. By combining this mathematical optimization program with an unsupervised machine learning algorithm, we are able to derive global-optimal gearbox designs for practically relevant momentum and speed requirements.}, language = {en} } @inproceedings{LeiseBreuerAltherretal.2020, author = {Leise, Philipp and Breuer, Tim and Altherr, Lena and Pelz, Peter F.}, title = {Development, validation and assessment of a resilient pumping system}, series = {Proceedings of the Joint International Resilience Conference, JIRC2020}, booktitle = {Proceedings of the Joint International Resilience Conference, JIRC2020}, isbn = {978-90-365-5095-6}, pages = {97 -- 100}, year = {2020}, abstract = {The development of resilient technical systems is a challenging task, as the system should adapt automatically to unknown disturbances and component failures. To evaluate different approaches for deriving resilient technical system designs, we developed a modular test rig that is based on a pumping system. On the basis of this example system, we present metrics to quantify resilience and an algorithmic approach to improve resilience. This approach enables the pumping system to automatically react on unknown disturbances and to reduce the impact of component failures. In this case, the system is able to automatically adapt its topology by activating additional valves. This enables the system to still reach a minimum performance, even in case of failures. Furthermore, timedependent disturbances are evaluated continuously, deviations from the original state are automatically detected and anticipated in the future. This allows to reduce the impact of future disturbances and leads to a more resilient system behaviour.}, language = {en} } @article{LeiseEsserEichenlaubetal.2021, author = {Leise, Philipp and Eßer, Arved and Eichenlaub, Tobias and Schleiffer, Jean-Eric and Altherr, Lena and Rinderknecht, Stephan and Pelz, Peter F.}, title = {Sustainable system design of electric powertrains - comparison of optimization methods}, series = {Engineering Optimization}, journal = {Engineering Optimization}, publisher = {Taylor \& Francis}, address = {London}, issn = {0305-215X}, doi = {10.1080/0305215X.2021.1928660}, year = {2021}, abstract = {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.}, language = {en} } @inproceedings{LeiseSimonAltherr2020, author = {Leise, Philipp and Simon, Nicolai and Altherr, Lena}, title = {Comparison of Piecewise Linearization Techniques to Model Electric Motor Efficiency Maps: A Computational Study}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48439-2}, doi = {10.1007/978-3-030-48439-2_55}, pages = {457 -- 463}, year = {2020}, abstract = {To maximize the travel distances of battery electric vehicles such as cars or buses for a given amount of stored energy, their powertrains are optimized energetically. One key part within optimization models for electric powertrains is the efficiency map of the electric motor. The underlying function is usually highly nonlinear and nonconvex and leads to major challenges within a global optimization process. To enable faster solution times, one possibility is the usage of piecewise linearization techniques to approximate the nonlinear efficiency map with linear constraints. Therefore, we evaluate the influence of different piecewise linearization modeling techniques on the overall solution process and compare the solution time and accuracy for methods with and without explicitly used binary variables.}, language = {en} } @inproceedings{LenzWolf2014, author = {Lenz, Laura L. and Wolf, Martin}, title = {Economic evaluation of serious games with the comparative assessment framework COSEGA}, series = {The shift from teaching to learning : individual, collective and organizational learning through gaming simulation ; proceedings of the 45th conference of the International Simulation and Gaming Association, Dornbirn 2014}, booktitle = {The shift from teaching to learning : individual, collective and organizational learning through gaming simulation ; proceedings of the 45th conference of the International Simulation and Gaming Association, Dornbirn 2014}, editor = {Kritz, Willy Christian}, publisher = {Bertelsmann}, address = {[Bielefeld]}, isbn = {978-3-7639-5422-3}, pages = {374 -- 386}, year = {2014}, language = {en} } @article{LerchlKruegerNiehausetal.2008, author = {Lerchl, Alexander and Kr{\"u}ger, Heike and Niehaus, Michael and Streckert, Joachim R. and Bitz, Andreas and Hansen, Volkert}, title = {Effects of mobile phone electromagnetic fields at nonthermal SAR values on melatonin and body weight of Djungarian hamsters (Phodopus sungorus)}, series = {Journal of Pineal Research}, volume = {44}, journal = {Journal of Pineal Research}, number = {3}, issn = {1600-079X}, doi = {10.1111/j.1600-079X.2007.00522.x}, pages = {267 -- 272}, year = {2008}, language = {en} } @inproceedings{LimpertSchifferFerrein2015, author = {Limpert, Nicolas and Schiffer, Stefan and Ferrein, Alexander}, title = {A Local Planner for Ackermann-Driven Vehicles in ROS SBPL}, series = {Proceedings of the International Conference on Pattern Recognition Association of South Africa and Robotics and Mechatronics (PRASA-RobMech), 2015}, booktitle = {Proceedings of the International Conference on Pattern Recognition Association of South Africa and Robotics and Mechatronics (PRASA-RobMech), 2015}, doi = {10.1109/RoboMech.2015.7359518}, pages = {172 -- 177}, year = {2015}, language = {en} } @article{LimpertWiesenFerreinetal.2019, author = {Limpert, Nicolas and Wiesen, Patrick and Ferrein, Alexander and Kallweit, Stephan and Schiffer, Stefan}, title = {The ROSIN Project and its Outreach to South Africa}, series = {R\&D Journal}, volume = {35}, journal = {R\&D Journal}, pages = {1 -- 6}, year = {2019}, language = {en} } @inproceedings{LindenlaufHoefkenSchuba2015, author = {Lindenlauf, Simon and H{\"o}fken, Hans-Wilhelm and Schuba, Marko}, title = {Cold Boot Attacks on DDR2 and DDR3 SDRAM}, series = {10th International Conference on Availability, Reliability and Security (ARES) 2015}, booktitle = {10th International Conference on Availability, Reliability and Security (ARES) 2015}, doi = {10.1109/ARES.2015.28}, pages = {287 -- 292}, year = {2015}, language = {en} } @inproceedings{LindnerKolbRingbeck2008, author = {Lindner, Marvin and Kolb, Andreas and Ringbeck, Thorsten}, title = {New insights into the calibration of ToF-sensors}, series = {2008 IEEE Computer Society Conference on Computer Vision and Pattern Recognition workshops : Anchorage, AK, 23 - 28 June 2008}, booktitle = {2008 IEEE Computer Society Conference on Computer Vision and Pattern Recognition workshops : Anchorage, AK, 23 - 28 June 2008}, publisher = {IEEE Service Center}, address = {Piscataway, NJ}, isbn = {978-1-4244-2339-2}, pages = {1 -- 5}, year = {2008}, abstract = {Time-of-flight (ToF) sensors have become an alternative to conventional distance sensing techniques like laser scanners or image based stereo. ToF sensors provide full range distance information at high frame-rates and thus have a significant impact onto current research in areas like online object recognition, collision prevention or scene reconstruction. However, ToF cameras like the photonic mixer device (PMD) still exhibit a number of challenges regarding static and dynamic effects, e.g. systematic distance errors and motion artefacts, respectively. Sensor calibration techniques reducing static system errors have been proposed and show promising results. However, current calibration techniques in general need a large set of reference data in order to determine the corresponding parameters for the calibration model. This paper introduces a new calibration approach which combines different demodulation techniques for the ToF- camera 's reference signal. Examples show, that the resulting combined demodulation technique yields improved distance values based on only two required reference data sets.}, language = {en} } @inproceedings{LogenHoefkenSchuba2012, author = {Logen, Steffen and H{\"o}fken, Hans and Schuba, Marko}, title = {Simplifying RAM Forensics : A GUI and Extensions for the Volatility Framework}, series = {2012 Seventh International Conference on Availability, Reliability and Security (ARES), 20-24 August 2012, Prague, Czech Republic}, booktitle = {2012 Seventh International Conference on Availability, Reliability and Security (ARES), 20-24 August 2012, Prague, Czech Republic}, publisher = {IEEE}, address = {New York}, isbn = {978-1-4673-2244-7}, doi = {10.1109/ARES.2012.12}, pages = {620 -- 624}, year = {2012}, abstract = {The Volatility Framework is a collection of tools for the analysis of computer RAM. The framework offers a multitude of analysis options and is used by many investigators worldwide. Volatility currently comes with a command line interface only, which might be a hinderer for some investigators to use the tool. In this paper we present a GUI and extensions for the Volatility Framework, which on the one hand simplify the usage of the tool and on the other hand offer additional functionality like storage of results in a database, shortcuts for long Volatility Framework command sequences, and entirely new commands based on correlation of data stored in the database.}, language = {en} } @inproceedings{LorenzAltherrPelz2020, author = {Lorenz, Imke-Sophie and Altherr, Lena and Pelz, Peter F.}, title = {Assessing and Optimizing the Resilience of Water Distribution Systems Using Graph-Theoretical Metrics}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, editor = {Neufeld, Janis S. and Buscher, Udo and Lasch, Rainer and M{\"o}st, Dominik and Sch{\"o}nberger, J{\"o}rn}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48439-2}, doi = {10.1007/978-3-030-48439-2_63}, pages = {521 -- 527}, year = {2020}, abstract = {Water distribution systems are an essential supply infrastructure for cities. Given that climatic and demographic influences will pose further challenges for these infrastructures in the future, the resilience of water supply systems, i.e. their ability to withstand and recover from disruptions, has recently become a subject of research. To assess the resilience of a WDS, different graph-theoretical approaches exist. Next to general metrics characterizing the network topology, also hydraulic and technical restrictions have to be taken into account. In this work, the resilience of an exemplary water distribution network of a major German city is assessed, and a Mixed-Integer Program is presented which allows to assess the impact of capacity adaptations on its resilience.}, language = {en} } @inproceedings{LorenzAltherrPelz2020, author = {Lorenz, Imke-Sophie and Altherr, Lena and Pelz, Peter F.}, title = {Resilience enhancement of critical infrastructure - graph-theoretical resilience analysis of the water distribution system in the German city of Darmstadt}, series = {14th WCEAM Proceedings}, booktitle = {14th WCEAM Proceedings}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-64228-0}, doi = {10.1007/978-3-030-64228-0_13}, pages = {137 -- 149}, year = {2020}, abstract = {Water suppliers are faced with the great challenge of achieving high-quality and, at the same time, low-cost water supply. Since climatic and demographic influences will pose further challenges in the future, the resilience enhancement of water distribution systems (WDS), i.e. the enhancement of their capability to withstand and recover from disturbances, has been in particular focus recently. To assess the resilience of WDS, graph-theoretical metrics have been proposed. In this study, a promising approach is first physically derived analytically and then applied to assess the resilience of the WDS for a district in a major German City. The topology based resilience index computed for every consumer node takes into consideration the resistance of the best supply path as well as alternative supply paths. This resistance of a supply path is derived to be the dimensionless pressure loss in the pipes making up the path. The conducted analysis of a present WDS provides insight into the process of actively influencing the resilience of WDS locally and globally by adding pipes. The study shows that especially pipes added close to the reservoirs and main branching points in the WDS result in a high resilience enhancement of the overall WDS.}, language = {en} } @inproceedings{LorenzAltherrPelz2019, author = {Lorenz, Imke-Sophie B. and Altherr, Lena and Pelz, Peter F.}, title = {Graph-theoretic resilience analysis of a water distribution system's topology}, series = {World Congress on Resilience, Reliability and Asset Management 2019}, booktitle = {World Congress on Resilience, Reliability and Asset Management 2019}, pages = {106 -- 109}, year = {2019}, abstract = {Water suppliers are faced with the great challenge of achieving high-quality and, at the same time, low-cost water supply. In practice, the focus is set on the most beneficial maintenance measures and/or capacity adaptations of existing water distribution systems (WDS). Since climatic and demographic influences will pose further challenges in the future, the resilience enhancement of WDS, i.e. the enhancement of their capability to withstand and recover from disturbances, has been in particular focus recently. To assess the resilience of WDS, metrics based on graph theory have been proposed. In this study, a promising approach is applied to assess the resilience of the WDS for a district in a major German City. The conducted analysis provides insight into the process of actively influencing the resilience of WDS}, language = {en} } @article{MaasVosLagemaatetal.2014, author = {Maas, Marnix C. and Vos, Eline K. and Lagemaat, Miriam W. and Bitz, Andreas and Orzada, Stephan and Kobus, Thiele and Kraff, Oliver and Maderwald, Stefan and Ladd, Mark E. and Scheenen, Tom W. J.}, title = {Feasibility of T₂-weighted turbo spin echo imaging of the human prostate at 7 tesla}, series = {Magnetic Resonance in Medicine}, volume = {71}, journal = {Magnetic Resonance in Medicine}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.24818}, pages = {1711 -- 1719}, year = {2014}, abstract = {Purpose To demonstrate that high quality T₂-weighted (T2w) turbo spin-echo (TSE) imaging of the complete prostate can be achieved routinely and within safety limits at 7 T, using an external transceive body array coil only. Methods Nine healthy volunteers and 12 prostate cancer patients were scanned on a 7 T whole-body system. Preparation consisted of B₀ and radiofrequency shimming and localized flip angle calibration. T₁ and T₂ relaxation times were measured and used to define the T2w-TSE protocol. T2w imaging was performed using a TSE sequence (pulse repetition time/echo time 3000-3640/71 ms) with prolonged excitation and refocusing pulses to reduce specific absorption rate. Results High quality T2w TSE imaging was performed in less than 2 min in all subjects. Tumors of patients with gold-standard tumor localization (MR-guided biopsy or prostatectomy) were well visualized on 7 T imaging (n = 3). The number of consecutive slices achievable within a 10-g averaged specific absorption rate limit of 10 W/kg was ≥28 in all subjects, sufficient for full prostate coverage with 3-mm slices in at least one direction. Conclusion High quality T2w TSE prostate imaging can be performed routinely and within specific absorption rate limits at 7 T with an external transceive body array.}, language = {en} } @inproceedings{MarcoFerrein2017, author = {Marco, Heather G. and Ferrein, Alexander}, title = {AGNES: The African-German Network of Excellence in Science}, series = {Proceedings of the 2nd Developing World Robotics Forum, Workshop at IEEE AFRICON 2017}, booktitle = {Proceedings of the 2nd Developing World Robotics Forum, Workshop at IEEE AFRICON 2017}, pages = {1 -- 2}, year = {2017}, language = {en} } @inproceedings{MatareSchifferFerrein2019, author = {Matar{\´e}, Victor and Schiffer, Stefan and Ferrein, Alexander}, title = {golog++ : An integrative system design}, series = {CogRob 2018. Cognitive Robotics Workshop : Proceedings of the 11th Cognitive Robotics Workshop 2018 co-located with 16th International Conference on Principles of Knowledge Representation and Reasoning (KR 2018) Tempe, AZ, USA, October 27th, 2018}, booktitle = {CogRob 2018. Cognitive Robotics Workshop : Proceedings of the 11th Cognitive Robotics Workshop 2018 co-located with 16th International Conference on Principles of Knowledge Representation and Reasoning (KR 2018) Tempe, AZ, USA, October 27th, 2018}, editor = {Steinbauer, Gerald and Ferrein, Alexander}, issn = {1613-0073}, pages = {29 -- 35}, year = {2019}, language = {en} } @article{MausHoefkenSchuba2011, author = {Maus, Stefan and H{\"o}fken, Hans-Wilhelm and Schuba, Marko}, title = {Forensic Analysis of Geodata in Android Smartphones}, pages = {1 -- 11}, year = {2011}, language = {en} } @article{Mayer1997, author = {Mayer, Claudia}, title = {L'Est{\´e}tique et le pouvoir: Le discours chaotique de l'Allemagne unifi{\´e}e}, series = {Canadian review of comparative literature : CRCL = Revue canadienne de litt{\´e}rature compar{\´e}e : RCLC / Canadian Comparative Literature Association. 24 (1997), H. 2}, journal = {Canadian review of comparative literature : CRCL = Revue canadienne de litt{\´e}rature compar{\´e}e : RCLC / Canadian Comparative Literature Association. 24 (1997), H. 2}, isbn = {0319-051X}, pages = {297 -- 317}, year = {1997}, language = {en} } @article{Mayer1993, author = {Mayer, Claudia}, title = {Between Trans- and Interdisciplinarity. »Germanistik« and the Dialectic of Inclusion and Exclusion of the Other(s)}, series = {Language and literature today : proceedings of the XIXth triennal congress of the International Federation for Modern Languages and Literatures ; Bras{\´i}lia 22 - 30 August 1993. General ed. Neide de Faria.}, journal = {Language and literature today : proceedings of the XIXth triennal congress of the International Federation for Modern Languages and Literatures ; Bras{\´i}lia 22 - 30 August 1993. General ed. Neide de Faria.}, publisher = {Univ.}, address = {Brasilia}, isbn = {85-230-0405-x}, pages = {958 -- 966}, year = {1993}, language = {en} } @article{Mayer1995, author = {Mayer, Claudia}, title = {Between Resistance and Affirmation: Christa Wolf and German Unification}, series = {Canadian review of comparative literature : CRCL = Revue canadienne de litt{\´e}rature compar{\´e}e / Canadian Comparative Literature Association. 22 (1995), H. 3-4}, journal = {Canadian review of comparative literature : CRCL = Revue canadienne de litt{\´e}rature compar{\´e}e / Canadian Comparative Literature Association. 22 (1995), H. 3-4}, isbn = {0319-051X}, pages = {813 -- 835}, year = {1995}, language = {en} } @book{Mayer2001, author = {Mayer, Claudia}, title = {Art : from prehistoric art to modernism / [Text: Claudia Mayer-Iswandy]}, publisher = {DuMont}, address = {K{\"o}ln}, isbn = {3-7701-7048-2}, pages = {[19] S. : zahlr. Ill. + Beil. (19 S.)}, year = {2001}, language = {en} } @inproceedings{MeckMuellerAltherretal.2020, author = {Meck, Marvin M. and M{\"u}ller, Tim M. and Altherr, Lena and Pelz, Peter F.}, title = {Improving an industrial cooling system using MINLP, considering capital and operating costs}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48438-5 (Print)}, doi = {10.1007/978-3-030-48439-2_61}, pages = {505 -- 512}, year = {2020}, abstract = {The chemical industry is one of the most important industrial sectors in Germany in terms of manufacturing revenue. While thermodynamic boundary conditions often restrict the scope for reducing the energy consumption of core processes, secondary processes such as cooling offer scope for energy optimisation. In this contribution, we therefore model and optimise an existing cooling system. The technical boundary conditions of the model are provided by the operators, the German chemical company BASF SE. In order to systematically evaluate different degrees of freedom in topology and operation, we formulate and solve a Mixed-Integer Nonlinear Program (MINLP), and compare our optimisation results with the existing system.}, language = {en} }