@inproceedings{UsaiCorucciGligorevicetal.2011, author = {Usai, Pierpaolo and Corucci, Alessandro and Gligorevic, Snjezana and Monorchio, Agostino}, title = {Estimation of airport surface propagation channel: ray tracing model and measurements}, series = {Proceedings of the 5th European Conference on Antennas and Propagation (EUCAP) : 11 - 15 April 2011, Rome, Italy}, booktitle = {Proceedings of the 5th European Conference on Antennas and Propagation (EUCAP) : 11 - 15 April 2011, Rome, Italy}, organization = {European Association on Antennas and Propagation}, isbn = {978-1-4577-0250-1}, pages = {1634 -- 1638}, year = {2011}, language = {en} } @inproceedings{SchifferFerreinLakemeyer2011, author = {Schiffer, Stefan and Ferrein, Alexander and Lakemeyer, Gerhard}, title = {Fuzzy representations and control for domestic service robots in Golog}, series = {Intelligent robotics and applications : 4th International conference, ICIRA 2011, Aachen, Germany, December 6-8, 2011, proceedings, part I. (Lecture notes in computer science ; 7102)}, booktitle = {Intelligent robotics and applications : 4th International conference, ICIRA 2011, Aachen, Germany, December 6-8, 2011, proceedings, part I. (Lecture notes in computer science ; 7102)}, isbn = {978-3-642-25486-4}, pages = {241 -- 250}, year = {2011}, language = {en} } @inproceedings{BragardRongeDeDoncker2011, author = {Bragard, Michael and Ronge, C. and De Doncker, R. W.}, title = {Sandwich design of high-power thyristor based devices with integrated MOSFET structure}, series = {Proceedings of the 2011 - 14th - European Conference on Power Electronics and Applications (EPE 2011) : Aug. 30, 2011 - Sept. 1, 2011, Birmingham, United Kingdom}, booktitle = {Proceedings of the 2011 - 14th - European Conference on Power Electronics and Applications (EPE 2011) : Aug. 30, 2011 - Sept. 1, 2011, Birmingham, United Kingdom}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-61284-167-0 (Print)}, year = {2011}, language = {en} } @inproceedings{BragardGottschlichDeDoncker2011, author = {Bragard, Michael and Gottschlich, J. and De Doncker, R. W.}, title = {Design and realization of a credit card size driver stage for high power thyristor based devices with integrated MOS structure}, series = {2011 IEEE 8th International Conference on Power Electronics and ECCE Asia (ICPE \& ECCE 2011) : Jeju, South Korea, 30 May 2011 - 3 June 2011 / [co-sponsored by the Korean Institute of Power Electronics ...]}, booktitle = {2011 IEEE 8th International Conference on Power Electronics and ECCE Asia (ICPE \& ECCE 2011) : Jeju, South Korea, 30 May 2011 - 3 June 2011 / [co-sponsored by the Korean Institute of Power Electronics ...]}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-61284-958-4 (Print)}, doi = {10.1109/ICPE.2011.5944661}, pages = {1182 -- 1189}, year = {2011}, language = {en} } @article{BragardConradvanHoeketal.2011, author = {Bragard, Michael and Conrad, M. and van Hoek, H. and De Doncker, R. W.}, title = {The integrated emitter turn-off thyristor (IETO) : an innovative thyristor-based high power semiconductor device using MOS assisted turn-off}, series = {IEEE transactions on industry applications}, volume = {47}, journal = {IEEE transactions on industry applications}, number = {5}, publisher = {IEEE}, address = {New York}, issn = {0093-9994}, doi = {10.1109/TIA.2011.2161432}, pages = {2175 -- 2182}, year = {2011}, language = {en} } @inproceedings{DammRitzStrauch2011, author = {Damm, Sebastian and Ritz, Thomas and Strauch, Jakob}, title = {Adaption of archetype patterns for mobile cloud-based business apps}, series = {2011 IEEE International Conference on Pervasive Computing and Communications workshops (PerCom workshops 2011) : Seattle, Washington, USA, 21 - 25 March 2011}, booktitle = {2011 IEEE International Conference on Pervasive Computing and Communications workshops (PerCom workshops 2011) : Seattle, Washington, USA, 21 - 25 March 2011}, publisher = {IEEE Service Center}, address = {Piscataway, NJ}, isbn = {978-1-61284-938-6 (Print)}, doi = {10.1109/PERCOMW.2011.5766849}, pages = {100 -- 105}, year = {2011}, language = {en} } @article{UmutluOrzadaKinneretal.2011, author = {Umutlu, Lale and Orzada, Stephan and Kinner, Sonja and Maderwald, Stefan and Bronte, Irina and Bitz, Andreas and Kraff, Oliver and Ladd, Susanne C. and Antoch, Gerald and Ladd, Mark E. and Quick, Harald H. and Lauenstein, Thomas C.}, title = {Renal imaging at 7 Tesla: preliminary results}, series = {European Radiology}, volume = {21}, journal = {European Radiology}, number = {4}, publisher = {Springer}, address = {Berlin}, issn = {1432-1084}, pages = {841 -- 849}, year = {2011}, abstract = {Objective To investigate the feasibility of 7T MR imaging of the kidneys utilising a custom-built 8-channel transmit/receive radiofrequency body coil. Methods In vivo unenhanced MR was performed in 8 healthy volunteers on a 7T whole-body MR system. After B0 shimming the following sequences were obtained: 1) 2D and 3D spoiled gradient-echo sequences (FLASH, VIBE), 2) T1-weighted 2D in and opposed phase 3) True-FISP imaging and 4) a T2-weighted turbo spin echo (TSE) sequence. Visual evaluation of the overall image quality was performed by two radiologists. Results Renal MRI at 7T was feasible in all eight subjects. Best image quality was found using T1-weighted gradient echo MRI, providing high anatomical details and excellent conspicuity of the non-enhanced vasculature. With successful shimming, B1 signal voids could be effectively reduced and/or shifted out of the region of interest in most sequence types. However, T2-weighted TSE imaging remained challenging and strongly impaired because of signal heterogeneities in three volunteers. Conclusion The results demonstrate the feasibility and diagnostic potential of dedicated 7T renal imaging. Further optimisation of imaging sequences and dedicated RF coil concepts are expected to improve the acquisition quality and ultimately provide high clinical diagnostic value.}, 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{KraffBitzBreyeretal.2011, author = {Kraff, Oliver and Bitz, Andreas and Breyer, Tobias and Kruszona, Stefan and Maderwald, Stefan and Brote, Irina and Gizewski, Elke R. and Ladd, Mark E. and Quick, Harald H.}, title = {A transmit/receive radiofrequency array for imaging the carotid arteries at 7 Tesla: coil design and first in vivo results}, series = {Investigative Radiology}, volume = {46}, journal = {Investigative Radiology}, number = {4}, publisher = {Wolters Kluwer}, address = {K{\"o}ln}, issn = {1536-0210}, doi = {10.1097/RLI.0b013e318206cee4}, pages = {246 -- 254}, year = {2011}, abstract = {Objective: To develop a transmit/receive radiofrequency (RF) array for magnetic resonance imaging (MRI) of the carotid arteries at 7 T. The prototype is characterized in numerical simulations and bench measurements, and the feasibility of plaque imaging at 7 T is demonstrated in first in vivo images. Materials and Methods: The RF phased array coil consists of 8 surface loop coils. To allow imaging of both sides of the neck, the RF array is divided into 2 coil clusters, each with 4 overlapping loop elements. For safety validation, numerical computations of the RF field distribution and the corresponding specific absorption rate were performed on the basis of a heterogeneous human body model. To validate the coil model, maps of the transmit B1+ field were compared between simulation and measurement. In vivo images of a healthy volunteer and a patient (ulcerating plaque and a 50\% stenosis of the right internal carotid artery) were acquired using a 3-dimensional FLASH sequence with a high isotropic spatial resolution of 0.54 mm as well as using pulse-triggered proton density (PD)/T2-weighted turbo spin echo sequences. Results: Measurements of the S-parameters yielded a reflection and isolation of the coil elements of better than -18 and -13 dB, respectively. Measurements of the g-factor indicated good image quality for parallel imaging acceleration factors up to 2.4. A similar distribution and a very good match of the absolute values were found between the measured and simulated B1+ transmit RF field for the validation of the coil model. In vivo images revealed good signal excitation of both sides of the neck and a high vessel-to-background image contrast for the noncontrast-enhanced 3-dimensional FLASH sequence. Imaging at 7 T could depict the extent of stenosis, and revealed the disruption and ulcer of the plaque. Conclusions: This study demonstrates that 2 four-channel transmit/receive RF arrays for each side of the neck is a suitable concept for in vivo MRI of the carotid arteries at 7 Tesla. Further studies are needed to explore and exploit the full potential of 7 T high-field MRI for carotid atherosclerotic plaque imaging.}, language = {en} } @article{ElQuardiStreckertBitzetal.2011, author = {El Quardi, A. and Streckert, J. and Bitz, Andreas and M{\"u}nkner, S. and Engel, J. and Hansen, V.}, title = {New fin-line devices for radiofrequency exposure of small biological samples in vitro allowing whole-cell patch clamp recordings}, series = {Bioelectromagnetics}, volume = {32}, journal = {Bioelectromagnetics}, number = {2}, publisher = {Wiley}, address = {Weinheim}, issn = {1521-186X}, doi = {10.1002/bem.20621}, pages = {102 -- 112}, year = {2011}, abstract = {The development and analysis of three waveguides for the exposure of small biological in vitro samples to mobile communication signals at 900 MHz (GSM, Global System for Mobile Communications), 1.8 GHz (GSM), and 2 GHz (UMTS, Universal Mobile Telecommunications System) is presented. The waveguides were based on a fin-line concept and the chamber containing the samples bathed in extracellular solution was placed onto two fins with a slot in between, where the exposure field concentrates. Measures were taken to allow for patch clamp recordings during radiofrequency (RF) exposure. The necessary power for the achievement of the maximum desired specific absorption rate (SAR) of 20 W/kg (average over the mass of the solution) was approximately Pin = 50 mW, Pin = 19 mW, and Pin = 18 mW for the 900 MHz, 1800 MHz, and 2 GHz devices, respectively. At 20 W/kg, a slight RF-induced temperature elevation in the solution of no more than 0.3 °C was detected, while no thermal offsets due to the electromagnetic exposure could be detected at the lower SAR settings (2, 0.2, and 0.02 W/kg). A deviation of 10\% from the intended solution volume yielded a calculated SAR deviation of 8\% from the desired value. A maximum ±10\% variation in the local SAR could occur when the position of the patch clamp electrode was altered within the area where the cells to be investigated were located.}, language = {en} }