@misc{GraesslRenzHezeletal.2012, author = {Gr{\"a}ßl, Andreas and Renz, Wolfgang and Hezel, Fabian and Frauenrath, Tobias and Pfeiffer, Harald and Hoffmann, Werner and Kellmann, Peter and Martin, Conrad and Niendorf, Thoralf}, title = {Design, evaluation and application of a modular 32 channel transmit/receive surface coil array for cardiac MRI at 7T}, series = {2012 ISMRM Annual Meeting Proceedings}, journal = {2012 ISMRM Annual Meeting Proceedings}, issn = {1545-4428}, year = {2012}, abstract = {Cardiac MR (CMR) at ultrahigh (≥7.0 T) fields is regarded as one of the most challenging MRI applications. At 7.0 T image quality is not always exclusively defined by signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Detrimental effects bear the potential to spoil the signal-to-noise (SNR) and contrast-to-noise (CNR) benefits of cardiac MR (CMR) at 7.0 T. B₁⁺-inhomogeneities and signal voids represent the main challenges. Various pioneering coil concepts have been proposed to tackle these issues, enabling cardiac MRI at 7.0 T. This includes a trend towards an ever larger number of transmit and receive channels. This approach affords multi-dimensional B₁⁺ modulations to improve B₁⁺ shimming performance and to enhance RF efficiency. Also, parallel imaging benefits from a high number of receive channels enabling two-dimensional acceleration. Realizing the limitations of existing coil designs tailored for UHF CMR and recognizing the opportunities of a many element TX/RX channel architecture this work proposes a modular, two dimensional 32-channel transmit and receive array using loop elements and examines its efficacy for enhanced B¹+ homogeneity and improved parallel imaging performance.}, language = {en} } @article{GrandeMeffertSchoenbergeretal.2012, author = {Grande, Marion and Meffert, Elisabeth and Schoenberger, Eva and Jung, Stefanie and Frauenrath, Tobias and Huber, Walter and Hussmann, Katja and Moormann, Mareike and Heim, Stefan}, title = {From a concept to a word in a syntactically complete sentence: An fMRI study on spontaneous language production in an overt picture description task}, series = {NeuroImage}, volume = {61}, journal = {NeuroImage}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1522-2586}, doi = {10.1016/j.neuroimage.2012.03.087}, pages = {702 -- 714}, year = {2012}, abstract = {Spontaneous language has rarely been subjected to neuroimaging studies. This study therefore introduces a newly developed method for the analysis of linguistic phenomena observed in continuous language production during fMRI. Most neuroimaging studies investigating language have so far focussed on single word or — to a smaller extent — sentence processing, mostly due to methodological considerations. Natural language production, however, is far more than the mere combination of words to larger units. Therefore, the present study aimed at relating brain activation to linguistic phenomena like word-finding difficulties or syntactic completeness in a continuous language fMRI paradigm. A picture description task with special constraints was used to provoke hesitation phenomena and speech errors. The transcribed speech sample was segmented into events of one second and each event was assigned to one category of a complex schema especially developed for this purpose. The main results were: conceptual planning engages bilateral activation of the precuneus. Successful lexical retrieval is accompanied - particularly in comparison to unsolved word-finding difficulties - by the left middle and superior temporal gyrus. Syntactic completeness is reflected in activation of the left inferior frontal gyrus (IFG) (area 44). In sum, the method has proven to be useful for investigating the neural correlates of lexical and syntactic phenomena in an overt picture description task. This opens up new prospects for the analysis of spontaneous language production during fMRI.}, language = {en} } @misc{GollewskiLangeRingbecketal.2012, author = {Gollewski, Torsten and Lange, Robert and Ringbeck, Thorsten and Hess, Holger and Buxbaum, Bernd}, title = {Verfahren und Vorrichtung zur Laufzeitsensitiven Messung eines Signals [Offenlegungsschrift / Europ{\"a}ische Patentschrift]}, publisher = {Deutsches Patent- und Markenamt / Europ{\"a}isches Patentamt}, address = {M{\"u}nchen / Den Hague}, year = {2012}, language = {de} } @inproceedings{FuchsRitzStrauch2012, author = {Fuchs, Britta and Ritz, Thomas and Strauch, Jakob}, title = {Usability of mobile applications : dissemination of usability engineering in small and medium enterprises}, series = {Proceedings of the International Conference on Data Communication Networking, e-Business and Optical Communication Systems : Rome, Italy, 24 - 27 July, 2012 ; [integrated in the ICETE (International Conference on e-Business and Telecommunications)]}, booktitle = {Proceedings of the International Conference on Data Communication Networking, e-Business and Optical Communication Systems : Rome, Italy, 24 - 27 July, 2012 ; [integrated in the ICETE (International Conference on e-Business and Telecommunications)]}, editor = {Obaidat, Mohammad S.}, publisher = {SciTePress}, address = {[Lissabon]}, isbn = {978-989-8565-23-5}, pages = {272 -- 277}, year = {2012}, language = {en} } @misc{FrauenrathPfeifferHezeletal.2012, author = {Frauenrath, Tobias and Pfeiffer, Harald and Hezel, Fabian and Dieringer, Matthias A. and Winter, Lukas and Gr{\"a}ßl, Andreas and Santoro, Davide and {\"O}zerdem, Celal and Renz, Wolfgang and Greiser, Andreas and Niendorf, Thoralf}, title = {Lessons learned from cardiac MRI at 7.0 T: LV function assessment at 3.0 T using local multi-channel transceiver coil arrays}, series = {2012 ISMRM Annual Meeting Proceedings}, journal = {2012 ISMRM Annual Meeting Proceedings}, issn = {1545-4428}, year = {2012}, abstract = {Cardiac MR (CMR) is of proven clinical value but also an area of vigorous ongoing research since image quality is not always exclusively defined by signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Recent developments of CMR at 7.0 T have been driven by pioneering explorations into novel multichannel transmit and receive coil array technology to tackle the challenges B1+-field inhomogeneities, to offset specific-absorption rate (SAR) constraints and to reduce banding artifacts in SSFP imaging. For this study, recognition of the benefits and performance of local surface Tx/Rx-array structures recently established at 7.0 T inspired migration to 3.0 T, where RF inhomogeneities and SAR limitations encountered in routine clinical CMR, though somewhat reduced versus the 7.0 T situation, remain significant. For all these reasons, this study was designed to build and examine the feasibility of a local four channel Tx/Rx cardiac coil array for anatomical and functional cardiac imaging at 3.0 T. For comparison, a homebuilt 4 channel Rx cardiac coil array exhibiting the same geometry as the Tx/Rx coil and a Rx surface coil array were used.}, language = {en} } @misc{FrauenrathNiendorf2012, author = {Frauenrath, Tobias and Niendorf, Thoralf}, title = {MRT-Vorrichtung und Verfahren zum Betreiben einer MRT-Vorrichtung}, year = {2012}, abstract = {A magnetic resonance tomography (MRT) apparatus (1) for the examination of a body (14) comprises parameter acquisition devices (13) for the acquisition of cardiovascular parameters of the body (14) and a control device (15) in communication with the parameter acquisition devices (13) for synchronizing the imaging, wherein the control device (15) is adapted to analyse the data of at least two parameter acquisition devices (13) and to output a control signal based on the analysis.}, language = {de} } @article{FrauenrathFuchsDieringeretal.2012, author = {Frauenrath, Tobias and Fuchs, Katharina and Dieringer, Matthias A. and {\"O}zerdem, Celal and Patel, Nishan and Renz, Wolfgang and Greiser, Andreas and Elgeti, Thomas and Niendorf, Thoralf}, title = {Detailing the use of magnetohydrodynamic effects for synchronization of MRI with the cardiac cycle: A feasibility study}, series = {Journal of Magnetic Resonance Imaging}, volume = {36}, journal = {Journal of Magnetic Resonance Imaging}, number = {2}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2586}, doi = {10.1002/jmri.23634}, pages = {364 -- 372}, year = {2012}, abstract = {Purpose: To investigate the feasibility of using magnetohydrodynamic (MHD) effects for synchronization of magnetic resonance imaging (MRI) with the cardiac cycle. Materials and Methods: The MHD effect was scrutinized using a pulsatile flow phantom at B0 = 7.0 T. MHD effects were examined in vivo in healthy volunteers (n = 10) for B0 ranging from 0.05-7.0 T. Noncontrast-enhanced MR angiography (MRA) of the carotids was performed using a gated steady-state free-precession (SSFP) imaging technique in conjunction with electrocardiogram (ECG) and MHD synchronization. Results: The MHD potential correlates with flow velocities derived from phase contrast MRI. MHD voltages depend on the orientation between B0 and the flow of a conductive fluid. An increase in the interelectrode spacing along the flow increases the MHD potential. In vivo measurement of the MHD effect provides peak voltages of 1.5 mV for surface areas close to the common carotid artery at B0 = 7.0 T. Synchronization of MRI with the cardiac cycle using MHD triggering is feasible. MHD triggered MRA of the carotids at 3.0 T showed an overall image quality and richness of anatomic detail, which is comparable to ECG-triggered MRAs. Conclusion: This feasibility study demonstrates the use of MHD effects for synchronization of MR acquisitions with the cardiac cycle. J. Magn. Reson. Imaging 2012;36:364-372. © 2012 Wiley Periodicals, Inc.}, language = {en} } @article{FerreinSteinbauerVassos2012, author = {Ferrein, Alexander and Steinbauer, Gerald and Vassos, Stavros}, title = {Action-Based Imperative Programming with YAGI}, pages = {24 -- 31}, year = {2012}, abstract = {Many tasks for autonomous agents or robots are best described by a specification of the environment and a specification of the available actions the agent or robot can perform. Combining such a specification with the possibility to imperatively program a robot or agent is what we call the actionbased imperative programming. One of the most successful such approaches is Golog. In this paper, we draft a proposal for a new robot programming language YAGI, which is based on the action-based imperative programming paradigm. Our goal is to design a small, portable stand-alone YAGI interpreter. We combine the benefits of a principled domain specification with a clean, small and simple programming language, which does not exploit any side-effects from the implementation language. We discuss general requirements of action-based programming languages and outline YAGI, our action-based language approach which particularly aims at embeddability.}, language = {en} } @article{FerreinMeyer2012, author = {Ferrein, Alexander and Meyer, Thomas}, title = {A Brief Overview of Artificial Intelligence in South Africa}, series = {AI Magazine}, volume = {33}, journal = {AI Magazine}, number = {1}, publisher = {AAAI}, address = {Menlo Park}, issn = {0738-4602}, doi = {10.1609/aimag.v33i1.2357}, pages = {99 -- 101}, year = {2012}, abstract = {South Africa in recent years is the establishment of a number of research hubs involved in AI activities ranging from mobile robotics and computational intelligence, to knowledge representation and reasoning, and human language technologies. In this survey we take the reader through a quick tour of the research being conducted at these hubs, and touch on an initiative to maintain and extend the current level of interest in AI research in the country.}, language = {en} } @inproceedings{EngelsSchnabel2012, author = {Engels, Elmar and Schnabel, Holger}, title = {Rapid-control-prototyping of industrial drives for the sercos automation bus}, series = {13th International Workshop on Mechatronics (MECATRONICS), 2012 9th France-Japan \& 7th Europe-Asia Congress on and Research and Education in Mechatronics (REM)}, booktitle = {13th International Workshop on Mechatronics (MECATRONICS), 2012 9th France-Japan \& 7th Europe-Asia Congress on and Research and Education in Mechatronics (REM)}, isbn = {978-1-4673-4771-6}, pages = {177 -- 181}, year = {2012}, abstract = {This article describes the functionality of a MATLAB® library that can be used to develop motion-logic applications in MATLAB programming language for industrial drive and control systems using the well known sercos automation bus. Therewith MATLAB's functionality is extended to designing automation applications from single axis machines up to multi-kinematic robots.}, language = {en} } @inproceedings{EngelsGabler2012, author = {Engels, Elmar and Gabler, T.}, title = {Universelle Programmierschnittstelle f{\"u}r Motion-Logic Systeme}, series = {Tagungsband zur AALE-Tagung 2012 : 9. Fachkonferenz}, booktitle = {Tagungsband zur AALE-Tagung 2012 : 9. Fachkonferenz}, publisher = {Oldenbourg Industrieverlag}, address = {M{\"u}nchen}, isbn = {978-3-8356-3305-6}, pages = {37 -- 46}, year = {2012}, language = {de} } @inproceedings{CzarneckiWinkelmannSpiliopoulou2012, author = {Czarnecki, Christian and Winkelmann, Axel and Spiliopoulou, Myra}, title = {Transformation in Telecommunication - Analyse und Clustering von Real-life Projekten}, series = {Multikonferenz Wirtschaftsinformatik 2012}, booktitle = {Multikonferenz Wirtschaftsinformatik 2012}, editor = {Mattfeld, Dirk Christian and Robra-Bissantz, Susanne}, publisher = {Gito}, address = {Berlin}, isbn = {9783942183635}, pages = {985 -- 998}, year = {2012}, abstract = {Die Ver{\"a}nderungen des Telekommunikationsmarktes haben in der Praxis zu einer Vielzahl von Transformationsprojekten gef{\"u}hrt. Was geh{\"o}rt aber zu einem "Transformationsprojekt", welche Prozesse und Systeme werden ver{\"a}ndert? Zur Beantwortung dieser Frage haben wir 184 Berichte zu Projekten analysiert, die als "Transformationsprojekte" bezeichnet waren. F{\"u}r die Analyse haben wir einen Kodierungsrahmen konzipiert und anhand dessen die Berichte mit einem hierarchischen Clustering-Verfahren in Themen gruppiert. Die Ergebnisse liefern Hinweise {\"u}ber die in der Praxis gesetzten Schwerpunkte und Priorit{\"a}ten. Sie k{\"o}nnen somit als Unterst{\"u}tzung f{\"u}r Unternehmen dienen, die ein Transformationsprojekt planen. Sie weisen zudem darauf hin, in welchen Bereichen eines Unternehmens Unterst{\"u}tzung durch wissenschaftlich erprobte Werkzeuge und Modelle n{\"o}tig ist.}, language = {de} } @article{CzarneckiSpiliopoulou2012, author = {Czarnecki, Christian and Spiliopoulou, Myra}, title = {A holistic framework for the implementation of a next generation network}, series = {International Journal of Business Information Systems}, volume = {9}, journal = {International Journal of Business Information Systems}, number = {4}, publisher = {Inderscience Enterprises}, address = {Olney, Bucks}, issn = {1746-0972}, doi = {10.1504/IJBIS.2012.046291}, pages = {385 -- 401}, year = {2012}, abstract = {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.}, language = {en} } @article{BragardvanHoekDeDoncker2012, author = {Bragard, Michael and van Hoek, H. and De Doncker, R. W.}, title = {A major design step in IETO concept realization that allows overcurrent protection and pushes limits of switching performance}, series = {IEEE transactions on power electronics}, volume = {27}, journal = {IEEE transactions on power electronics}, number = {9}, publisher = {IEEE}, address = {New York}, issn = {0885-8993}, doi = {10.1109/TPEL.2012.2189136}, pages = {4163 -- 4171}, year = {2012}, abstract = {This paper presents the latest prototype of the integrated emitter turn-off thyristor concept, which potentially ranks among thyristor high-power devices like the gate turn-off thyristor and the integrated gate-commutated thyristor (IGCT). Due to modifications of the external driver stage and mechanical press-pack design optimization, this prototype allows for full device characterization. The turn-off capability was increased to 1600 A with an active silicon area of 823mm2 . This leads to a transient peak power of 672.1kW/cm² . Within this paper, measurements and concept assessment are presented and a comparison to state-of-the-art IGCT devices is provided.}, language = {en} } @phdthesis{Bragard2012, author = {Bragard, Michael}, title = {The integrated emitter turn-off thyristor : an innovative MOS-gated high-power device. - (Aachener Beitr{\"a}ge des ISEA ; 62)}, publisher = {Shaker}, address = {Aachen}, isbn = {978-3-8440-1152-4}, pages = {III, 164 S. : Ill., graph. Darst.}, year = {2012}, abstract = {This thesis introduces the Integrated Emitter Turn-Off (IETO) Thyristor as a new high-power device. Known state-of-the-art research activities like the Dual GCT, the ETO thyristor and the ICT were presented and critically reviewed. A comparison with commercialized solutions identifies the pros and cons of each type of device family. Based on this analysis, the IETO structure is proposed, covering most benefits of each device class. In particular the combination of a MOS-assisted turn-off with a thyristor-based device allows a voltage-controlled MOS switching and the low on-state voltage of the thyristors. The following synthesis of an IETO device stands on a three-dimensional field of optimization spanned by electric, mechanical and thermal aspects. From an electric point of view, the lowest possible parasitic inductance and resistance within the commutation path are optimization criteria. The mechanical construction has to withstand the required contact pressure of multiple kilo Newtons. Finally, thermal borders limit the maximum average current of the device. FEM simulations covering these three aspects are performed for several design proposals. An IETO prototype is constructed and measurements on various test benches attest thermal, mechanical and electric performance. A local decoupling of the external driver stage and the presspack housing is presented by a cable connection. This separation enables a thermal and mechanical independence, which is advantageous in terms of vibrations and thermal cycles including increased reliability. The electric pulse performance of the prototype device is a factor of 3.1 above today''s solutions. In single-pulse measurements, a current up to 1600 A was successfully turned off at 115°C with an active silicon area of 823 mm². One reason for this increased turn-off capability is the extremely low-inductive construction. Additional functionality of the IETO thyristor like over-current self-protection and defined short-circuit failure state are successfully verified.}, language = {en} } @article{BragardBragard2012, author = {Bragard, G. and Bragard, Michael}, title = {Ein kosteng{\"u}nstiges, universelles Modellbauinterface}, series = {Der mathematische und naturwissenschaftliche Unterricht : MNU ; Organ des Deutschen Vereins zur F{\"o}rderung des Mathematischen und Naturwissenschaftlichen Unterrichts e.V.}, volume = {65}, journal = {Der mathematische und naturwissenschaftliche Unterricht : MNU ; Organ des Deutschen Vereins zur F{\"o}rderung des Mathematischen und Naturwissenschaftlichen Unterrichts e.V.}, number = {5}, publisher = {Seeberger}, address = {Neuss}, issn = {0025-5866}, pages = {290 -- 293}, year = {2012}, abstract = {Wir stellen einen USB-Baustein vor, der eine kosteng{\"u}nstige und universelle M{\"o}glichkeit schafft , im Unterricht den Themenkreis Messen-Steuern-Regeln zu behandeln. Die Funktionalit{\"a}t orientiert sich am CVK-Interface der Firma Fischertechnik. Im Gegensatz zu kommerziellen L{\"o}sungen erlaubt unser Aufbau auch den preiswerten Einsatz in Gruppen- oder Einzelarbeit. Abschließend berichten wir {\"u}ber ein Beispiel aus dem Unterrichtseinsatz.}, language = {de} } @inproceedings{BitzKraffOrzadaetal.2012, author = {Bitz, Andreas and Kraff, O. and Orzada, S. and Maderwald, S. and Brote, I. and Johst, S. and Ladd, E.}, title = {Assessment of RF Safety of Transmit Coils at 7 Tesla by Experimental and Numerical Procedures (490.)}, series = {19th annual ISMRM scientific meeting and exhibition 2011 : Montreal, Quebec, Canada, 7 - 13 May 2011}, booktitle = {19th annual ISMRM scientific meeting and exhibition 2011 : Montreal, Quebec, Canada, 7 - 13 May 2011}, number = {Volume 1}, publisher = {Curran}, address = {Red Hook, NY}, isbn = {978-1-61839-284-8}, pages = {475}, year = {2012}, language = {en} }