TY  - JOUR
A1  - Franke, Helmut
A1  - Streckert, Joachim
A1  - Bitz, Andreas
A1  - Goeke, Johannes
A1  - Hansen, Volkert
A1  - Ringelstein, E. Bernd
A1  - Nattkämper, Heiner
A1  - Galle, Hans-Joachim
A1  - Stögbauer, Florian
T1  - Effects of Universal Mobile Telecommunications System (UMTS) electromagnetic fields on the blood-brain barrier in vitro
JF  - Radiation Research
Y1  - 2005
U6  - http://dx.doi.org/10.1667/RR3424.1
SN  - 1938-5404
VL  - 164
IS  - 3
SP  - 258
EP  - 269
ER  - 
TY  - JOUR
A1  - Foltz, Christian
A1  - Schneider, Nicole
A1  - Wolf, Martin
A1  - Kausch, Bernhard
A1  - Schlick, Christopher
A1  - Luczak, Holger
ED  - Nagl, Manfred
T1  - Usability engineering
JF  - Collaborative and distributed chemical engineering : from understanding to substantial design process support; results of the IMPROVE Project. - (Lecture notes in computer science ; 4970)
Y1  - 2008
SN  - 978-3-540-70552-9
U6  - http://dx.doi.org/10.1007/978-3-540-70552-9_21
SP  - 527
EP  - 554
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Fiedler, Thomas M.
A1  - Orzada, Stephan
A1  - Flöser, Martina
A1  - Rietsch, Stefan H. G.
A1  - Schmidt, Simon
A1  - Stelter, Jonathan K.
A1  - Wittrich, Marco
A1  - Quick, Harald H.
A1  - Bitz, Andreas
A1  - Ladd, Mark E.
T1  - Performance and safety assessment of an integrated transmitarray for body imaging at 7 T under consideration of specificabsorption rate, tissue temperature, and thermal dose
JF  - NMR in Biomedicine
N2  - In this study, the performance of an integrated body-imaging array for 7 T with 32 radiofrequency (RF) channels under consideration of local specific absorption rate (SAR), tissue temperature, and thermal dose limits was evaluated and the imaging performance was compared with a clinical 3 T body coil.

Thirty-two transmit elements were placed in three rings between the bore liner and RF shield of the gradient coil. Slice-selective RF pulse optimizations for B1 shimming and spokes were performed for differently oriented slices in the body under consideration of realistic constraints for power and local SAR. To improve the B1+ homogeneity, safety assessments based on temperature and thermal dose were performed to possibly allow for higher input power for the pulse optimization than permissible with SAR limits.

The results showed that using two spokes, the 7 T array outperformed the 3 T birdcage in all the considered regions of interest. However, a significantly higher SAR or lower duty cycle at 7 T is necessary in some cases to achieve similar B1+ homogeneity as at 3 T. The homogeneity in up to 50 cm-long coronal slices can particularly benefit from the high RF shim performance provided by the 32 RF channels. The thermal dose approach increases the allowable input power and the corresponding local SAR, in one example up to 100 W/kg, without limiting the exposure time necessary for an MR examination.

In conclusion, the integrated antenna array at 7 T enables a clinical workflow for body imaging and comparable imaging performance to a conventional 3 T clinical body coil.
KW  - body imaging at 7 T MRI
KW  - thermal dose
KW  - tissue temperature
KW  - transmit antenna arrays
Y1  - 2022
U6  - http://dx.doi.org/10.1002/nbm.4656
SN  - 0952-3480 (Print)
SN  - 1099-1492 (Online)
VL  - 35
IS  - 5
SP  - 1
EP  - 17
PB  - Wiley
ER  - 
TY  - JOUR
A1  - Fiedler, Thomas M.
A1  - Ladd, Mark E.
A1  - Clemens, Markus
A1  - Bitz, Andreas
T1  - Safety of subjects during radiofrequency exposure in ultra-high-field magnetic resonance imaging
JF  - IEEE Letters on Electromagnetic Compatibility Practice and Applications
N2  - Magnetic resonance imaging (MRI) is one of the most important medical imaging techniques. Since the introduction of MRI in the mid-1980s, there has been a continuous trend toward higher static magnetic fields to obtain i.a. a higher signal-to-noise ratio. The step toward ultra-high-field (UHF) MRI at 7 Tesla and higher, however, creates several challenges regarding the homogeneity of the spin excitation RF transmit field and the RF exposure of the subject. In UHF MRI systems, the wavelength of the RF field is in the range of the diameter of the human body, which can result in inhomogeneous spin excitation and local SAR hotspots. To optimize the homogeneity in a region of interest, UHF MRI systems use parallel transmit systems with multiple transmit antennas and time-dependent modulation of the RF signal in the individual transmit channels. Furthermore, SAR increases with increasing field strength, while the SAR limits remain unchanged. Two different approaches to generate the RF transmit field in UHF systems using antenna arrays close and remote to the body are investigated in this letter. Achievable imaging performance is evaluated compared to typical clinical RF transmit systems at lower field strength. The evaluation has been performed under consideration of RF exposure based on local SAR and tissue temperature. Furthermore, results for thermal dose as an alternative RF exposure metric are presented.
Y1  - 2020
SN  - 2637-6423
U6  - http://dx.doi.org/10.1109/LEMCPA.2020.3029747
VL  - 2
IS  - 3
SP  - 1
EP  - 8
PB  - IEEE
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Fiedler, Thomas M.
A1  - Ladd, Mark E.
A1  - Bitz, Andreas
T1  - SAR Simulations & Safety
JF  - NeuroImage
Y1  - 2017
U6  - http://dx.doi.org/10.1016/j.neuroimage.2017.03.035
SN  - 1053-8119
IS  - Epub ahead of print
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Fiedler, Thomas M.
A1  - Ladd, Mark E.
A1  - Bitz, Andreas
T1  - RF safety assessment of a bilateral four-channel transmit/receive 7 Tesla breast coil: SAR versus temperature limits
JF  - Medical Physics
Y1  - 2017
U6  - http://dx.doi.org/10.1002/mp.12034
N1  - This article is corrected by:
Errata: Erratum: “RF safety assessment of a bilateral four-channel transmit/receive 7 Tesla breast coil: SAR versus tissue temperature limits” [Med. Phys. 44(1), 143–157 (2017)] Volume 44, Issue 2, 772
VL  - 44
IS  - 1
SP  - 143
EP  - 157
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Strack, Andreas
A1  - Lakemeyer, Gerhard
T1  - Laser-Based Localization with Sparse Landmarks  / Strack, Andreas ; Ferrein, Alexander ; Lakemeyer, Gerhard
JF  - RoboCup 2005: Robot Soccer World Cup IX
Y1  - 2006
SN  - 978-3-540-35437-6
N1  - Lecture Notes in Computer Science ; 4020
SP  - 569
EP  - 576
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Steinbauer, Gerald
A1  - Vassos, Stavros
T1  - Action-Based Imperative Programming with YAGI
N2  - 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.
Y1  - 2012
N1  - Cognitive Robotics
AAAI Technical Report WS-12-06
SP  - 24
EP  - 31
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Steinbauer, Gerald
A1  - McPhillips, Graeme
A1  - Potgieter, Anet
T1  - RoboCup Standard Platform League - Team Zadeat : an intercontinental research effort
Y1  - 2008
SP  - 1
EP  - 7
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Steinbauer, Gerald
A1  - McPhillips, Graeme
A1  - Potgieter, Anet
T1  - Establishing the RoboCup Standard League in Africa - applying for the RoboCup Standard League with a German-Austrian-South African Research Project
Y1  - 2007
SP  - 1
EP  - 5
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Steinbauer, Gerald
A1  - McPhillips, Graeme
A1  - Niemüller, Tim
A1  - Potgieter, Anet
T1  - Team Zadeat 2009 : team report
Y1  - 2009
VL  - 6
SP  - 1
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Steinbauer, Gerald
T1  - On the Way to High-Level Programming for Resource-Limited Embedded Systems with Golog
JF  - Simulation, Modeling, and Programming for Autonomous Robots
Y1  - 2010
N1  - Lecture Notes in Computer Science ; 6472 ; Second International Conference, SIMPAR 2010, Darmstadt, Germany, November 15-18, 2010. Proceedings
SP  - 229
EP  - 240
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Steinbauer, Gerald
T1  - 20 Years of RoboCup -  A Subjective Retrospection
JF  - KI - Künstliche Intelligenz
N2  - This summer, RoboCup competitions were held for the 20th time in Leipzig, Germany. It was the second time that RoboCup took place in Germany, 10 years after the 2006 RoboCup in Bremen. In this article, we give an overview on the latest developments of RoboCup and what happened in the different leagues over the last decade. With its 20th edition, RoboCup clearly is a success story and a role model for robotics competitions. From our personal view point, we acknowledge this by giving a retrospection about what makes RoboCup such a success.
Y1  - 2016
U6  - http://dx.doi.org/10.1007/s13218-016-0449-5
SN  - 1610-1987
VL  - 30
IS  - 3
SP  - 225
EP  - 232
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Steinbauer, Gerald
T1  - The Interplay of Aldebaran and RoboCup
JF  - KI - Künstliche Intelligenz
Y1  - 2016
U6  - http://dx.doi.org/10.1007/s13218-016-0440-1
SN  - 1610-1987
VL  - 30
IS  - 3-4
SP  - 325
EP  - 326
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Steinbauer, Gerald
T1  - Looking back on 20 Years of RoboCup
JF  - KI - Künstliche Intelligenz
Y1  - 2016
U6  - http://dx.doi.org/10.1007/s13218-016-0443-y
SN  - 1610-1987
VL  - 30
IS  - 3-4
SP  - 321
EP  - 323
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Siebel, Nils T.
A1  - Steinbauer, Gerald
T1  - Hybrid control for autonomous systems — Integrating learning, deliberation and reactive control
JF  - Robotics and Autonomous Systems
Y1  - 2010
SN  - 0921-8890
VL  - 58
IS  - 9
SP  - 1037
EP  - 1038
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Schiffer, Stefan
A1  - Lakemeyer, Gerhard
T1  - Embedding fuzzy controllers in golog  / Ferrein, Alexander ; Schiffer, Stefan ; Lakemeyer, Gerhard
JF  - IEEE International Conference on Fuzzy Systems, 2009. FUZZ-IEEE 2009
Y1  - 2009
SN  - 978-1-4244-3596-8
SP  - 894
EP  - 899
PB  - IEEE
CY  - New York
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Schiffer, Stefan
A1  - Lakemeyer, Gerhard
T1  - A Fuzzy Set Semantics for Qualitative Fluents in the Situation Calculus / Ferrein, Alexander ; Schiffer, Stefan ; Lakemeyer, Gerhard
JF  - Intelligent Robotics and Applications : First International Conference, ICIRA 2008 Wuhan, China, October 15-17, 2008 Proceedings, Part I
Y1  - 2008
N1  - Lecture Notes in Computer Science ; 5314
SP  - 498
EP  - 509
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Schiffer, Stefan
A1  - Lakemeyer, Gerhard
T1  - Football is coming Home / Schiffer, Stefan ; Ferrein, Alexander ; Lakemeyer, Gerhard
JF  - PCAR '06 Proceedings of the 2006 international symposium on Practical cognitive agents and robots
Y1  - 2006
SN  - 1-74052-130-7
SP  - 39
EP  - 50
PB  - ACM
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Ferrein, Alexander
A1  - Schiffer, Stefan
A1  - Lakemeyer, Gerhard
T1  - Qualitative World Models for Soccer Robots / Schiffer, Stefan ; Ferrein, Alexander ; Lakemeyer, Gerhard
JF  - Qualitative constraint calculi : application and integration ; KI 2006, 14 - 19 June 2006, Bremen, Germany ; 29th Annual German Conference on Artificial Intelligence ; workshop / Stefan Wölfl ... (eds.)
Y1  - 2006
SN  - 3-88722-666-6
SP  - 3
EP  - 14
PB  - Univ.
CY  - Bremen
ER  -