@article{SammFaissnerGoettlicheretal.1992, author = {Samm, Doris and Faissner, H. and G{\"o}ttlicher, P. and Matela, H.}, title = {Search for scalar and pseudoscalar bosons emitted in nuclear decays via their interactions / Faissner, H.; Goettlicher, P. ; Matela, H. ; Samm, D.}, series = {Zeitschrift f{\"u}r Physik A Hadrons and Nuclei. 341 (1992), H. 3}, journal = {Zeitschrift f{\"u}r Physik A Hadrons and Nuclei. 341 (1992), H. 3}, pages = {359 -- 364}, year = {1992}, language = {en} } @article{SammFaissnerFrenzeletal.1980, author = {Samm, Doris and Faissner, H. and Frenzel, E. and Heinrigs, W.}, title = {Limit on axion decay into an electron pair / H. Faissner, E. Frenzel, W. Heinrigs, A. Preussger, D. Samm und U. Samm}, series = {Physics Letters B. Vol. 96 (1980), H. Issues 1-2}, journal = {Physics Letters B. Vol. 96 (1980), H. Issues 1-2}, pages = {201 -- 205}, year = {1980}, language = {en} } @article{SammFaissnerFrenzeletal.1980, author = {Samm, Doris and Faissner, H. and Frenzel, E. and Heinrigs, W.}, title = {Observation of the two-photon decay of a light penetrating particle / H. Faissner, E. Frenzel, W. Heinrigs, A. Preussger, D. Samm und U. Samm}, series = {Physics Letters B. Vol. 103 (1980), H. Issues 3}, journal = {Physics Letters B. Vol. 103 (1980), H. Issues 3}, pages = {234 -- 240}, year = {1980}, language = {en} } @article{SammBosetti1990, author = {Samm, Doris and Bosetti, P.-C.}, title = {Testmessungen an einem grossflaechigen (Durchmesser 35 cm) Photomultiplier Test measurements of a large-area (diameter 35 cm) photomultiplier / Bosetti, P.-C.; ... Samm, D. [u.a.]}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft. 25 (1990), H. 1}, journal = {Verhandlungen der Deutschen Physikalischen Gesellschaft. 25 (1990), H. 1}, pages = {33 -- 33}, year = {1990}, language = {en} } @article{SammBosetti1990, author = {Samm, Doris and Bosetti, P.-C.}, title = {DUMAND und die Suche nach extraterrestrischen Neutrinos / DUMAND and the search for extraterrestrial neutrinos / Bosetti, P.-C.; ... Samm, D. [u.a.]}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft. 25 (1990), H. 1}, journal = {Verhandlungen der Deutschen Physikalischen Gesellschaft. 25 (1990), H. 1}, pages = {88 -- 88}, year = {1990}, language = {en} } @article{Samm1994, author = {Samm, Doris}, title = {DUMAND and the search for high energy neutrino point sources / Samm, Doris [u.a.]}, series = {Trends in astroparticle physics / ed. by Peter Christian Bosetti}, journal = {Trends in astroparticle physics / ed. by Peter Christian Bosetti}, publisher = {Teubner}, address = {Stuttgart}, isbn = {3-8154-3017-8}, pages = {9 -- 20}, year = {1994}, language = {en} } @article{RoepkeKoehlerDruryetal.2020, author = {Roepke, Rene and K{\"o}hler, Klemens and Drury, Vincent and Schroeder, Ulrik and Wolf, Martin R. and Meyer, Ulrike}, title = {A pond full of phishing games - analysis of learning games for anti-phishing education}, series = {Model-driven Simulation and Training Environments for Cybersecurity. MSTEC 2020}, journal = {Model-driven Simulation and Training Environments for Cybersecurity. MSTEC 2020}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-62433-0}, doi = {10.1007/978-3-030-62433-0_32020}, pages = {41 -- 60}, year = {2020}, abstract = {Game-based learning is a promising approach to anti-phishing education, as it fosters motivation and can help reduce the perceived difficulty of the educational material. Over the years, several prototypes for game-based applications have been proposed, that follow different approaches in content selection, presentation, and game mechanics. In this paper, a literature and product review of existing learning games is presented. Based on research papers and accessible applications, an in-depth analysis was conducted, encompassing target groups, educational contexts, learning goals based on Bloom's Revised Taxonomy, and learning content. As a result of this review, we created the publications on games (POG) data set for the domain of anti-phishing education. While there are games that can convey factual and conceptual knowledge, we find that most games are either unavailable, fail to convey procedural knowledge or lack technical depth. Thus, we identify potential areas of improvement for games suitable for end-users in informal learning contexts.}, language = {en} } @article{RitzStender2006, author = {Ritz, Thomas and Stender, Michael}, title = {Modeling of B2B mobile commerce processes}, series = {International Journal of Production Economics}, volume = {101}, journal = {International Journal of Production Economics}, number = {1}, issn = {0925-5273}, doi = {10.1016/j.ijpe.2005.05.017}, pages = {128 -- 139}, year = {2006}, language = {en} } @article{Ritz2000, author = {Ritz, Thomas}, title = {Information Channels}, series = {Information Technology. Nr. 52 (2000), H. 08. Mai 2000}, journal = {Information Technology. Nr. 52 (2000), H. 08. Mai 2000}, pages = {15 -- 15}, year = {2000}, language = {en} } @article{Ritz2002, author = {Ritz, Thomas}, title = {Modelling Production of personalized information services and their delivery on multiple distribution channels}, series = {Personalization Techniques in Electronic Publishing on the Web. Workshop in the Framework of the 2nd international conference on Adaptive Hypermedia and adaptive web based systems (AH2002) in Malaga (ES)}, journal = {Personalization Techniques in Electronic Publishing on the Web. Workshop in the Framework of the 2nd international conference on Adaptive Hypermedia and adaptive web based systems (AH2002) in Malaga (ES)}, pages = {19 -- 30}, year = {2002}, language = {en} } @article{Ritz2002, author = {Ritz, Thomas}, title = {Modelling mass customization of digital news services}, series = {International journal of e-business strategy management}, volume = {3}, journal = {International journal of e-business strategy management}, number = {3}, year = {2002}, language = {en} } @article{Ritz2000, author = {Ritz, Thomas}, title = {Personalized information services : an electronic information commodity and its production}, series = {International Journal of E-Business Strategy Management}, volume = {2}, journal = {International Journal of E-Business Strategy Management}, number = {2}, issn = {1467-0305}, year = {2000}, language = {en} } @article{Ritz2002, author = {Ritz, Thomas}, title = {Mass Customized Production of Information Services - The combination of economies-of-scale with economies-of-scope}, series = {Media firms : structures, operations, and performance ; [World Media Economics Conference, 5th : 2002 : Turku, Finland] / ed. by Robert G. Picard}, journal = {Media firms : structures, operations, and performance ; [World Media Economics Conference, 5th : 2002 : Turku, Finland] / ed. by Robert G. Picard}, publisher = {Erlbaum}, address = {Mahwah, NJ [u.a.]}, isbn = {0-8058-4165-2}, pages = {267 S. : graph. Darst.}, year = {2002}, language = {en} } @article{Ritz2002, author = {Ritz, Thomas}, title = {Personalized Information Services: Production and Distribution of these Services employing Mass-Customization}, year = {2002}, language = {en} } @article{RietschPfaffenrotBitzetal.2017, author = {Rietsch, Stefan H. G. and Pfaffenrot, Viktor and Bitz, Andreas and Orzada, Stephan and Brunheim, Sascha and Lazik-Palm, Andrea and Theysohn, Jens M. and Ladd, Mark E. and Quick, Harald H. and Kraff, Oliver}, title = {An 8-channel transceiver 7-channel receive RF coil setup for high SNR ultrahigh-field MRI of the shoulder at 7T}, series = {Medical Physics}, journal = {Medical Physics}, number = {Article in press}, publisher = {Wiley}, address = {Hoboken}, issn = {0094-2405}, doi = {10.1002/mp.12612}, year = {2017}, language = {en} } @article{RietschBrunheimOrzadaetal.2019, author = {Rietsch, Stefan H. G. and Brunheim, Sascha and Orzada, Stephan and Voelker, Maximilian N. and Maderwald, Stefan and Bitz, Andreas and Gratz, Marcel and Ladd, Mark E. and Quick, Harald H.}, title = {Development and evaluation of a 16-channel receive-only RF coil to improve 7T ultra-high field body MRI with focus on the spine}, series = {Magnetic Resonance in Medicine}, journal = {Magnetic Resonance in Medicine}, number = {Early view}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.27731}, year = {2019}, language = {en} } @article{RensVarzinczakMeyeretal.2010, author = {Rens, Gavin and Varzinczak, Ivan and Meyer, Thomas and Ferrein, Alexander}, title = {A Logic for Reasoning about Actions and Explicit Observations}, series = {AI 2010: Advances in Artificial Intelligence 23rd Australasian Joint Conference, Adelaide, Australia, December 7-10, 2010. Proceedings}, journal = {AI 2010: Advances in Artificial Intelligence 23rd Australasian Joint Conference, Adelaide, Australia, December 7-10, 2010. Proceedings}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-642-17431-5}, pages = {395 -- 404}, year = {2010}, language = {en} } @article{RensFerrein2013, author = {Rens, Gavin and Ferrein, Alexander}, title = {Belief-node condensation for online POMDP algorithms}, publisher = {IEEE}, address = {New York}, pages = {1 -- 7}, year = {2013}, abstract = {Slightly extended version of the paper accepted at the Robotics and Artificial Intelligence Workshop, a special track of IEEE AFRICON-2013, held in Mauritius, 9-12 September 2013}, language = {en} } @article{ReinhardtBitzElOuardietal.2007, author = {Reinhardt, T. and Bitz, Andreas and El Ouardi, A. and Streckert, J. and Sommer, A. and Lerchl, A. and Hansen, V.}, title = {Exposure set-ups for in vivo experiments using radial waveguides}, series = {Radiation Protection Dosimetry}, volume = {124}, journal = {Radiation Protection Dosimetry}, number = {1}, issn = {1742-3406}, doi = {10.1093/rpd/ncm370}, pages = {21 -- 26}, year = {2007}, language = {en} } @article{RauschFriesenAltherretal.2018, author = {Rausch, Lea and Friesen, John and Altherr, Lena and Meck, Marvin and Pelz, Peter F.}, title = {A holistic concept to design optimal water supply infrastructures for informal settlements using remote sensing data}, series = {Remote Sensing}, volume = {10}, journal = {Remote Sensing}, number = {2}, publisher = {MDPI}, address = {Basel}, isbn = {2072-4292}, doi = {10.3390/rs10020216}, pages = {1 -- 23}, year = {2018}, abstract = {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.}, language = {en} } @article{PoettgenEdererAltherretal.2015, author = {P{\"o}ttgen, Philipp and Ederer, Thorsten and Altherr, Lena and Lorenz, Ulf and Pelz, Peter F.}, title = {Examination and optimization of a heating circuit for energy-efficient buildings}, series = {Energy Technology}, volume = {4}, journal = {Energy Technology}, number = {1}, publisher = {WILEY-VCH Verlag}, address = {Weinheim}, isbn = {2194-4296}, doi = {10.1002/ente.201500252}, pages = {136 -- 144}, year = {2015}, abstract = {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 Zortstr{\"o}m 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.}, language = {en} } @article{PrumeZalachasLaskewitzetal.2008, author = {Prume, Klaus and Zalachas, Nicolas and Laskewitz, Bernd and Kamlah, Marc}, title = {Effective Piezoelectric Coefficients of Ferroelectric Thin Films on Elastic Substrates / Zalachas, Nicolas ; Laskewitz, Bernd ; Kamlah, Marc ; Prume, Klaus ; Lapusta, Yuri ; Tiedke, Stephan}, series = {Journal of Intelligent Material Systems and Structures. 20 (2008), H. 6}, journal = {Journal of Intelligent Material Systems and Structures. 20 (2008), H. 6}, isbn = {1045-389X}, pages = {683 -- 695}, year = {2008}, language = {en} } @article{PrumeWaserFrankenetal.2000, author = {Prume, Klaus and Waser, Rainer and Franken, Klaus and Maier, Horst R.}, title = {Finite-Element Analysis of Ceramic Multilayer Capacitors: Modeling and Electrical Impedance Spectroscopy for a Nondestructive Failure Test / Prume, Klaus ; Waser, Rainer ; Franken, Klaus ; Maier, Horst R. ;}, series = {Journal of the American Ceramic Society. 83 (2000), H. 5}, journal = {Journal of the American Ceramic Society. 83 (2000), H. 5}, isbn = {0002-7820}, pages = {1153 -- 1159}, year = {2000}, language = {en} } @article{PrumeWaser2000, author = {Prume, Klaus and Waser, Rainer}, title = {Finite-element simulation of coupled characteristics of ceramic multilayer capacitors under transient electrical loading / Prume, Klaus ; Waser, Rainer}, series = {Proceedings of the 2000 12th IEEE International Symposium on Applications of Ferroelectrics. Vol. 2}, journal = {Proceedings of the 2000 12th IEEE International Symposium on Applications of Ferroelectrics. Vol. 2}, pages = {675 -- 678}, year = {2000}, language = {en} } @article{PrumeTyholdtCalameetal.2007, author = {Prume, Klaus and Tyholdt, F. and Calame, F. and Raeder, H.}, title = {Chemically derived seeding layer for {100}-textured PZT thin films / Tyholdt, F. ; Calame, F. ; Prume, K. ; Raeder, H. ; Muralt, P.}, series = {Journal of Electroceramics. 19 (2007), H. 4}, journal = {Journal of Electroceramics. 19 (2007), H. 4}, isbn = {1385-3449}, pages = {311 -- 314}, year = {2007}, language = {en} } @article{PrumeTiedkeSchmitzetal.2001, author = {Prume, Klaus and Tiedke, S. and Schmitz, T. and Roelofs, A.}, title = {Direct hysteresis measurements of single nanosized ferroelectric capacitors contacted with an atomic force microscope / Tiedke, S. ; Schmitz, T. ; Prume, K. ; Roelofs, A. ; Schneller, T. ; Kall, U. ; Waser, R. ; Ganpule, C. S. ; Nagarajan, V. ; Stanishevs}, series = {Applied Physics Letters. 79 (2001), H. 22}, journal = {Applied Physics Letters. 79 (2001), H. 22}, isbn = {0003-6951}, pages = {3678 -- 3680}, year = {2001}, language = {en} } @article{PrumeRoelofsSchmitzetal.2002, author = {Prume, Klaus and Roelofs, Andreas and Schmitz, Thorsten and Reichenberg, Bernd}, title = {Compensation of the Parasitic Capacitance of a Scanning Force Microscope Cantilever Used for Measurements on Ferroelectric Capacitors of Submicron Size by Means of Finite Element Simulations / Prume, Klaus ; Roelofs, Andreas ; Schmitz, Thorsten ; Reichenb}, series = {Japanese Journal of Applied Physics. 41 (2002), H. 11B}, journal = {Japanese Journal of Applied Physics. 41 (2002), H. 11B}, isbn = {0021-4922}, pages = {7198 -- 7201}, year = {2002}, language = {en} } @article{PrumeReichenbergRoelofsetal.2004, author = {Prume, Klaus and Reichenberg, B. and Roelofs, A. and Waser, R.}, title = {In-situ compensation of the parasitic capacitance for nanoscale hysteresis measurements / Schmitz, T. ; Prume, K. ; Reichenberg, B. ; Roelofs, A. ; Waser, R. ; Tiedke, S.}, series = {Journal of the European Ceramic Society. 24 (2004), H. 6}, journal = {Journal of the European Ceramic Society. 24 (2004), H. 6}, isbn = {0955-2219}, pages = {1145 -- 1147}, year = {2004}, language = {en} } @article{PrumeRaederTyholdtetal.2007, author = {Prume, Klaus and Raeder, H. and Tyholdt, F. and Booij, W. E.}, title = {Taking piezoelectric microsystems from the laboratory to production / Raeder, H. ; Tyholdt, F. ; Booij, W. ; Calame, F. ; Ostbo, N. P. ; Bredesen, R. ; Prume, K. ; Rijnders, G. ; Muralt, P.}, series = {Journal of Electroceramics. 19 (2007), H. 4}, journal = {Journal of Electroceramics. 19 (2007), H. 4}, isbn = {1385-3449}, pages = {357 -- 362}, year = {2007}, language = {en} } @article{PrumePeterRuedigeretal.2005, author = {Prume, Klaus and Peter, F. and R{\"u}diger, A. and Dittmann, R.}, title = {Analysis of shape effects on the piezoresponse in ferroelectric nanograins with and without adsorbates / Peter, F. ; R{\"u}diger, A. ; Dittmann, R. ; Waser, R. ; Szot, K. ; Reichenberg, B. ; Prume, K. ;}, series = {Applied Physics Letters . 87 (2005), H. 8}, journal = {Applied Physics Letters . 87 (2005), H. 8}, isbn = {0003-6951}, pages = {082901 -- 082901-3}, year = {2005}, language = {en} } @article{PrumeMuraltCalameetal.2007, author = {Prume, Klaus and Muralt, Paul and Calame, Florian and Schmitz-Kempen, Thorsten}, title = {Extensive electromechanical characterization of PZT thin films for MEMS applications by electrical and mechanical excitation signals / Prume, Klaus ; Muralt, Paul ; Calame, Florian ; Schmitz-Kempen, Thorsten ; Tiedke, Stephan}, series = {Journal of Electroceramics. 19 (2007), H. 4}, journal = {Journal of Electroceramics. 19 (2007), H. 4}, isbn = {1385-3449}, pages = {407 -- 411}, year = {2007}, language = {en} } @article{PrumeMuraltCalameetal.2007, author = {Prume, Klaus and Muralt, P. and Calame, F. and Schmitz-Kempen, T.}, title = {Piezoelectric thin films: evaluation of electrical and electromechanical characteristics for MEMS devices / Prume, K. ; Muralt, P. ; Calame, F. ; Schmitz-Kempen, T. ; Tiedke, S. ;}, series = {IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. 54 (2007), H. 1}, journal = {IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. 54 (2007), H. 1}, isbn = {0885-3010}, pages = {81 -- 14}, year = {2007}, language = {en} } @article{PrumeMeyerWaseretal.2005, author = {Prume, Klaus and Meyer, Ren{\´e} and Waser, Rainer and Schmitz, Torsten}, title = {Dynamic leakage current compensation in ferroelectric thin-film capacitor structures / Meyer, Ren{\´e} ; Waser, Rainer ; Prume, Klaus ; Schmitz, Torsten ; Tiedke, Stephan}, series = {Applied Physics Letters . 86 (2005), H. 14}, journal = {Applied Physics Letters . 86 (2005), H. 14}, isbn = {0003-6951}, pages = {142907-1 -- 142907-3}, year = {2005}, language = {en} } @article{PrumeGerberKuegeleretal.2004, author = {Prume, Klaus and Gerber, Peter and K{\"u}geler, Carsten and Roelofs, Andreas}, title = {Simulation and measurements of the piezoelectric properties response (d33) of piezoelectric layered thin film structures influenced by the top-electrode size / Prume, K. ; Gerber, P. ; K{\"u}geler, C. ; Roelofs, A. ; B{\"o}ttger, U. ; Waser, R. ; Schmitz-Kempen,}, isbn = {0-7803-8410-5}, pages = {7 -- 10}, year = {2004}, language = {en} } @article{PrumeGerberRoelofsetal.2004, author = {Prume, Klaus and Gerber, P. and Roelofs, A. and K{\"u}geler, C.}, title = {Effects of the top-electrode size on the piezoelectric properties (d33 and S) of lead zirconate titanate thin films / Gerber, P. ; Roelofs, A. ; K{\"u}geler, C.; B{\"o}ttger, U. ; Waser, R. ; Prume, K. ;}, series = {Journal of Applied Physics . 96 (2004), H. 5}, journal = {Journal of Applied Physics . 96 (2004), H. 5}, isbn = {0021-8979}, pages = {2800 -- 2804}, year = {2004}, language = {en} } @article{PrumeFrankenMaieretal.2000, author = {Prume, Klaus and Franken, Klaus and Maier, Horst R. and Waser, Rainer}, title = {Finite-Element Analysis of Ceramic Multilayer Capacitors: Failure Probability Caused by Wave Soldering and Bending Loads / Franken, Klaus ; Maier, Horst R. ; Prume, Klaus ; Waser, Rainer}, series = {Journal of the American Ceramic Society. 83 (2000), H. 6}, journal = {Journal of the American Ceramic Society. 83 (2000), H. 6}, isbn = {0002-7820}, pages = {1433 -- 1440}, year = {2000}, language = {en} } @article{PrumeFrankenBoettgeretal.2002, author = {Prume, Klaus and Franken, Klaus and B{\"o}ttger, Ulrich and Waser, Rainer}, title = {Modelling and numerical simulation of the electrical, mechanical, and thermal coupled behaviour of Multilayer capacitors (MLCs) / Prume, Klaus ; Franken, Klaus ; B{\"o}ttger, Ulrich ; Waser, Rainer ; Maier, Horst R.}, series = {Journal of the European Ceramic Society. 22 (2002), H. 8}, journal = {Journal of the European Ceramic Society. 22 (2002), H. 8}, isbn = {0955-2219}, pages = {1285 -- 1296}, year = {2002}, language = {en} } @article{PrumeBooijVogletal.2007, author = {Prume, Klaus and Booij, W. E. and Vogl, A. H. and Wang, D. T.}, title = {A simple and powerful analytical model for MEMS piezoelectric multimorphs / Booij, W. E. ; Vogl, A. H. ; Wang, D. T. ; Tyholdt, F. ; Ostbo, N. P. ; Raeder, H. ; Prume, K.}, series = {Journal of Electroceramics. 19 (2007), H. 4}, journal = {Journal of Electroceramics. 19 (2007), H. 4}, isbn = {1385-3449}, pages = {387 -- 393}, year = {2007}, language = {en} } @article{Prume2007, author = {Prume, Klaus}, title = {Electrical and electromechanical characterization of piezoelectric thin films in view of MEMS application / Tiedke, S. ; Prume, K. ; Schmitz-Kempen, T.;}, pages = {702}, year = {2007}, language = {en} } @article{ProchnowGebingLadageetal.2011, author = {Prochnow, Nora and Gebing, Tina and Ladage, Kerstin and Krause-Finkeldey, Dorothee and Ourdi, Abessamad El and Bitz, Andreas and Streckert, Joachim and Hansen, Volkert and Dermietzel, Rolf}, title = {Electromagnetic field effect or simply stress? Effects of UMTS exposure on hippocampal longterm plasticity in the context of procedure related hormone release}, series = {PLoS one}, volume = {6}, journal = {PLoS one}, number = {5}, publisher = {PLOS}, address = {San Francisco}, doi = {10.1371/journal.pone.0019437}, pages = {e19437}, year = {2011}, abstract = {Harmful effects of electromagnetic fields (EMF) on cognitive and behavioural features of humans and rodents have been controversially discussed and raised persistent concern about adverse effects of EMF on general brain functions. In the present study we applied radio-frequency (RF) signals of the Universal Mobile Telecommunications System (UMTS) to full brain exposed male Wistar rats in order to elaborate putative influences on stress hormone release (corticosteron; CORT and adrenocorticotropic hormone; ACTH) and on hippocampal derived synaptic long-term plasticity (LTP) and depression (LTD) as electrophysiological hallmarks for memory storage and memory consolidation. Exposure was computer controlled providing blind conditions. Nominal brain-averaged specific absorption rates (SAR) as a measure of applied mass-related dissipated RF power were 0, 2, and 10 W/kg over a period of 120 min. Comparison of cage exposed animals revealed, regardless of EMF exposure, significantly increased CORT and ACTH levels which corresponded with generally decreased field potential slopes and amplitudes in hippocampal LTP and LTD. Animals following SAR exposure of 2 W/kg (averaged over the whole brain of 2.3 g tissue mass) did not differ from the sham-exposed group in LTP and LTD experiments. In contrast, a significant reduction in LTP and LTD was observed at the high power rate of SAR (10 W/kg). The results demonstrate that a rate of 2 W/kg displays no adverse impact on LTP and LTD, while 10 W/kg leads to significant effects on the electrophysiological parameters, which can be clearly distinguished from the stress derived background. Our findings suggest that UMTS exposure with SAR in the range of 2 W/kg is not harmful to critical markers for memory storage and memory consolidation, however, an influence of UMTS at high energy absorption rates (10 W/kg) cannot be excluded.}, language = {en} } @article{OssmannKazay2000, author = {Oßmann, Martin and Kazay, B.}, title = {Simple circuit provides high-side current sensing / Ossmann, M ; Kazay, B.}, series = {EDN. 45 (2000), H. 21}, journal = {EDN. 45 (2000), H. 21}, isbn = {0012-7515}, pages = {200 -- 200}, year = {2000}, language = {en} } @article{OssmannKazay1999, author = {Oßmann, Martin and Kazay, B.}, title = {Single mu C pin makes half-duplex RS-232C / Ossmann, M}, series = {EDN. 44 (1999), H. 16}, journal = {EDN. 44 (1999), H. 16}, isbn = {0012-7515}, pages = {118}, year = {1999}, language = {en} } @article{OssmannHattrupBroeck2003, author = {Oßmann, Martin and Hattrup, C. and Broeck, H. W. van der}, title = {Fast estimation techniques for digital control of resonant converters / Hattrup, C.; van der Broeck, H.W.; Ossmann, M.;}, series = {IEEE Transaction on Power Electronics. 18 (2003), H. 1}, journal = {IEEE Transaction on Power Electronics. 18 (2003), H. 1}, isbn = {0885-8993}, pages = {365 -- 372}, year = {2003}, language = {en} } @article{OrzadaSolbachGratzetal.2019, author = {Orzada, Stephan and Solbach, Klaus and Gratz, Marcel and Brunheim, Sascha and Fiedler, Thomas M. and Johst, S{\"o}ren and Bitz, Andreas and Shooshtary, Samaneh and Abuelhaija, Asjraf and Voelker, Maximilian N. and Rietsch, Stefan H. G. and Kraff, Oliver and Maderwald, Stefan and Fl{\"o}ser, Martina and Oehmingen, Mark and Quick, Harald H. and Ladd, Mark E.}, title = {A 32-channel parallel transmit system add-on for 7T MRI}, series = {Plos one}, journal = {Plos one}, doi = {10.1371/journal.pone.0222452}, year = {2019}, language = {en} } @article{OrzadaMaderwaldPoseretal.2010, author = {Orzada, Stephan and Maderwald, Stefan and Poser, Benedikt Andreas and Bitz, Andreas and Quick, Harald H. and Ladd, Mark E.}, title = {RF excitation using time interleaved acquisition of modes (TIAMO) to address B1 inhomogeneity in high-field MRI}, series = {Magnetic Resonance in Medicine}, volume = {64}, journal = {Magnetic Resonance in Medicine}, number = {2}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2594}, doi = {10.1002/mrm.22527}, pages = {327 -- 333}, year = {2010}, abstract = {As the field strength and, therefore, the operational frequency in MRI is increased, the wavelength approaches the size of the human head/body, resulting in wave effects, which cause signal decreases and dropouts. Several multichannel approaches have been proposed to try to tackle these problems, including RF shimming, where each element in an array is driven by its own amplifier and modulated with a certain (constant) amplitude and phase relative to the other elements, and Transmit SENSE, where spatially tailored RF pulses are used. In this article, a relatively inexpensive and easy to use imaging scheme for 7 Tesla imaging is proposed to mitigate signal voids due to B1 field inhomogeneity. Two time-interleaved images are acquired using a different excitation mode for each. By forming virtual receive elements, both images are reconstructed together using GRAPPA to achieve a more homogeneous image, with only small SNR and SAR penalty in head and body imaging at 7 Tesla.}, language = {en} } @article{OrzadaLaddBitz2016, author = {Orzada, Stephan and Ladd, Mark E. and Bitz, Andreas}, title = {A method to approximate maximum local SAR in multichannel transmit MR systems without transmit phase information}, series = {Magnetic Resonance in Medicine}, volume = {78}, journal = {Magnetic Resonance in Medicine}, number = {2}, publisher = {International Society for Magnetic Resonance in Medicine}, issn = {1522-2594}, doi = {10.1002/mrm.26398}, pages = {805 -- 811}, year = {2016}, abstract = {Purpose To calculate local specific absorption rate (SAR) correctly, both the amplitude and phase of the signal in each transmit channel have to be known. In this work, we propose a method to derive a conservative upper bound for the local SAR, with a reasonable safety margin without knowledge of the transmit phases of the channels. Methods The proposed method uses virtual observation points (VOPs). Correction factors are calculated for each set of VOPs that prevent underestimation of local SAR when the VOPs are applied with the correct amplitudes but fixed phases. Results The proposed method proved to be superior to the worst-case calculation based on the maximum eigenvalue of the VOPs. The mean overestimation for six coil setups could be reduced, whereas no underestimation of the maximum local SAR occurred. In the best investigated case, the overestimation could be reduced from a factor of 3.3 to a factor of 1.7. Conclusion The upper bound for the local SAR calculated with the proposed method allows a fast estimation of the local SAR based on power measurements in the transmit channels and facilitates SAR monitoring in systems that do not have the capability to monitor transmit phases}, language = {en} } @article{OrzadaJohstMaderwaldetal.2013, author = {Orzada, Stephan and Johst, S{\"o}ren and Maderwald, Stefan and Bitz, Andreas and Solbach, Klaus and Ladd, Mark E.}, title = {Mitigation of B1(+) inhomogeneity on single-channel transmit systems with TIAMO}, series = {Magnetic Resonance in Medicine}, volume = {70}, journal = {Magnetic Resonance in Medicine}, number = {1}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.24453}, pages = {290 -- 294}, year = {2013}, language = {en} } @article{OrzadaFiedlerBitzetal.2020, author = {Orzada, Stephan and Fiedler, Thomas M. and Bitz, Andreas and Ladd, Mark E. and Quick, Harald H.}, title = {Local SAR compression with overestimation control to reduce maximum relative SAR overestimation and improve multi-channel RF array performance}, series = {Magnetic Resonance Materials in Physics, Biology and Medicine}, journal = {Magnetic Resonance Materials in Physics, Biology and Medicine}, number = {34 (2021)}, publisher = {Springer}, address = {Heidelberg}, isbn = {1352-8661}, doi = {10.1007/s10334-020-00890-0}, pages = {153 -- 164}, year = {2020}, abstract = {Objective In local SAR compression algorithms, the overestimation is generally not linearly dependent on actual local SAR. This can lead to large relative overestimation at low actual SAR values, unnecessarily constraining transmit array performance. Method Two strategies are proposed to reduce maximum relative overestimation for a given number of VOPs. The first strategy uses an overestimation matrix that roughly approximates actual local SAR; the second strategy uses a small set of pre-calculated VOPs as the overestimation term for the compression. Result Comparison with a previous method shows that for a given maximum relative overestimation the number of VOPs can be reduced by around 20\% at the cost of a higher absolute overestimation at high actual local SAR values. Conclusion The proposed strategies outperform a previously published strategy and can improve the SAR compression where maximum relative overestimation constrains the performance of parallel transmission.}, language = {en} } @article{OrzadaBitzSchaeferetal.2011, author = {Orzada, Stephan and Bitz, Andreas and Sch{\"a}fer, Lena C. and Ladd, Susanne C. and Ladd, Mark E. and Maderwald, Stefan}, title = {Open design eight-channel transmit/receive coil for high-resolution and real-time ankle imaging at 7 T}, series = {Medical Physics}, volume = {38}, journal = {Medical Physics}, number = {3}, publisher = {Wiley}, address = {Hoboken}, issn = {2473-4209}, doi = {10.1118/1.3553399}, pages = {1162 -- 1167}, year = {2011}, abstract = {Purpose: At 1.5 T, real-time MRI of joint movement has been shown to be feasible. However, 7 T, provides higher SNR and thus an improved potential for parallel imaging acceleration. The purpose of this work was to build an open, U-shaped eight-channel transmit/receive microstrip coil for 7 T MRI to enable high-resolution and real-time imaging of the moving ankle joint. Methods: A U-shaped eight-channel transmit/receive array for the human ankle was built.urn:x-wiley:00942405:mp3399:equation:mp3399-math-0001-parameters and urn:x-wiley:00942405:mp3399:equation:mp3399-math-0002-factor were measured. SAR calculations of different ankle postures were performed to ensure patient safety. Inhomogeneities in the transmit field consequent to the open design were compensated for by the use of static RF shimming. High-resolution and real-time imaging was performed in human volunteers. Results: The presented array showed good performance with regard to patient comfort and image quality. High acceleration factors of up to 4 are feasible without visible acceleration artifacts. Reasonable image homogeneity was achieved with RF shimming. Conclusions: Open, noncylindrical designs for transmit/receive coils are practical at 7 T and real-time imaging of the moving joint is feasible with the presented coil design.}, language = {en} } @article{OrzadaBitzJohstetal.2017, author = {Orzada, Stephan and Bitz, Andreas and Johst, S{\"o}ren and Gratz, Marcel and V{\"o}lker, Maximilian N. and Kraff, Oliver and Abuelhaija, Ashraf and Fiedler, Thomas M. and Solbach, Klaus and Quick, Harald H. and Ladd, Mark E.}, title = {Analysis of an integrated 8-Channel Tx/Rx body array for use as a body coil in 7-Tesla MRI}, series = {Frontiers in Physics}, volume = {5}, journal = {Frontiers in Physics}, number = {Jun}, issn = {2296-424X}, doi = {10.3389/fphy.2017.00017}, year = {2017}, language = {en} }