TY - JOUR
A1 - Ferrein, Alexander
A1 - Meyer, Thomas
T1 - A Brief Overview of Artificial Intelligence in South Africa
JF - AI Magazine
N2 - 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.
Y1 - 2012
U6 - https://doi.org/10.1609/aimag.v33i1.2357
SN - 0738-4602
VL - 33
IS - 1
SP - 99
EP - 101
PB - AAAI
CY - Menlo Park
ER -
TY - JOUR
A1 - Ferrein, Alexander
A1 - Mies, Christoph
A1 - Lakemeyer, Gerhard
T1 - Repairing Decision-Theoretic Policies Using Goal-Oriented Planning / Mies, Christoph ; Ferrein, Alexander ; Lakemeyer, Gerhard
JF - KI 2008: Advances in Artificial Intelligence : 31st Annual German Conference on AI, KI 2008, Kaiserslautern, Germany, September 23-26, 2008. Proceedings
Y1 - 2008
SN - 978-3-540-85844-7
N1 - Lecture Notes in Computer Science ; 5243
SP - 267
EP - 275
PB - Springer
CY - Berlin
ER -
TY - CHAP
A1 - Ferrein, Alexander
A1 - Niemüller, Tim
A1 - Schiffer, Stefan
A1 - Lakemeyer, Gerhard
ED - Boots, Byron
T1 - Lessons learnt from developing the embodied AI platform CAESAR for domestic service robotics
T2 - Designing intelligent robots : reintegrating AI II ; papers from the AAAI spring symposium ; [held March 25 - 27, 2013 in Palo Alto, California, USA, on the campus of Stanford University]. (Technical Report / Association for the Advancement of Artificial Intelligence ; 2013,4)
Y1 - 2013
SN - 9781577356011
SP - 21
EP - 26
ER -
TY - JOUR
A1 - Ferrein, Alexander
A1 - Niemüller, Tim
A1 - Steinbauer, Gerald
T1 - Team Zadeat 2010 : application for participation
Y1 - 2010
ER -
TY - BOOK
A1 - Ferrein, Alexander
A1 - Pauli, J.
A1 - Siebel, N. T.
A1 - Steinbauer, Gerald
T1 - Hybrid control for autonomous systems : [... 1st Workshop on Hybrid Control of Autonomous Systems - Integrating Learning, Deliberation and Reactive Control with the 21st International Joint Conference on Artificial Intelligence (IJCAI-09), held in Pasadena, CA, in July 2009] / ed. by Alexander Ferrein ...
Y1 - 2009
ER -
TY - CHAP
A1 - Ferrein, Alexander
A1 - Potgieter, Anet
A1 - Steinbauer, Gerald
T1 - Self-aware robots - What do we need from learning, deliberation, and reactive control?
T2 - HYCAS 2009 : International Workshop on Hybrid Control of Autonomous Systems : Integrating Learning, Deliberation and Reactive Control : Pasadena, Calif., 13 July 2009
Y1 - 2009
SP - 1
EP - 5
PB - AAAI Pr.
ER -
TY - JOUR
A1 - Ferrein, Alexander
A1 - Rens, Gavin
A1 - Meyer, Thomas
A1 - Lakemeyer, Gerhard
T1 - A Logic for Specifying Partially Observable Stochastic Domains / Rens, Gavin ; Meyer, Thomas ; Ferrein, Alexander ; Lakemeyer, Gerhard
JF - Proceedings of the Ninth International Workshop pn non-Monotonic Reasoning, Action and Change (NRAC`11)
Y1 - 2011
N1 - Technical Report RMIT-TR-11-02
SP - 15
EP - 22
ER -
TY - JOUR
A1 - Ferrein, Alexander
A1 - Rens, Gavin
A1 - Poel, Etienne van der
T1 - A BDI agent architecture for a POMDP planner / Rens, Gavin ; Ferrein, Alexander ; Poel, Etienne van der
Y1 - 2009
N1 - 9th International Symposium on Logical Formalization of Commonsense Reasoning: Commonsense 2009, Toronto, Canada, 1-3 June, 2009
SP - 1
EP - 6
ER -
TY - JOUR
A1 - Ferrein, Alexander
A1 - Schiffer, Stefan
A1 - Booysen, T.
A1 - Stopforth, R.
T1 - Why it is harder to run RoboCup in South Africa: Experiences from German South African collaborations
JF - International Journal of Advanced Robotic Systems
N2 - Robots are widely used as a vehicle to spark interest in science and technology in learners. A number of initiatives focus on this issue, for instance, the Roberta Initiative, the FIRST Lego League, the World Robot Olympiad and RoboCup Junior. Robotic competitions are valuable not only for school learners but also for university students, as the RoboCup initiative shows. Besides technical skills, the students get some project exposure and experience what it means to finish their tasks on time. But qualifying students for future high-tech areas should not only be for students from developed countries. In this article, we present our experiences with research and education in robotics within the RoboCup initiative, in Germany and South Africa; we report on our experiences with trying to get the RoboCup initiative in South Africa going. RoboCup has a huge support base of academic institutions in Germany; this is not the case in South Africa. We present our ‘north–south’ collaboration initiatives in RoboCup between Germany and South Africa and discuss some of the reasons why we think it is harder to run RoboCup in South Africa.
Y1 - 2016
U6 - https://doi.org/10.1177/1729881416662789
SN - 1729-8806
VL - 13
IS - 5
SP - 1
EP - 13
ER -
TY - CHAP
A1 - Ferrein, Alexander
A1 - Schiffer, Stefan
A1 - Kallweit, Stephan
T1 - The ROSIN Education Concept - Fostering ROS Industrial-Related Robotics Education in Europe
T2 - ROBOT 2017: Third Iberian Robotics Conference
Y1 - 2018
SN - 978-3-319-70836-2
U6 - https://doi.org/10.1007/978-3-319-70836-2_31
N1 - Advances in Intelligent Systems and Computing, vol 694;
(AISC, volume 694)
SP - 370
EP - 381
PB - Springer
CY - Cham
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 -
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 - 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 - CHAP
A1 - Ferrein, Alexander
A1 - Scholl, Ingrid
A1 - Neumann, Tobias
A1 - Krückel, Kai
A1 - Schiffer, Stefan
T1 - A system for continuous underground site mapping and exploration
Y1 - 2019
U6 - https://doi.org/10.5772/intechopen.85859
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 - 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 - https://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 - Looking back on 20 Years of RoboCup
JF - KI - Künstliche Intelligenz
Y1 - 2016
U6 - https://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 - Steinbauer, Gerald
T1 - The Interplay of Aldebaran and RoboCup
JF - KI - Künstliche Intelligenz
Y1 - 2016
U6 - https://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 - 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
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
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 - 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 - 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 - 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 - CHAP
A1 - Feuerriegel, Uwe
A1 - Pook, Michael
A1 - Wersch, Gregor
A1 - Wittenhorst, Simon
A1 - Becker, Jürgen
A1 - Ecker, Markus
A1 - Hoffmann, Ulrich
A1 - Kunz, Ulrich
T1 - Simulation von Wärmeübertragungsprozessen
N2 - Mit freundlicher Genehmigung der Autoren und des Oldenbourg Industrieverlags https://www.oldenbourg-industrieverlag.de/de/9783835633223-33223 erschienen als Beitrag im Tagungsband zur AALE-Tagung 2012. 9. Fachkonferenz 4.-5. Mai 2012, Aachen, Fachhochschule. ISBN 9783835633223 S 5-1 S. 127-135 Es werden Ergebnisse unterschiedlicher Projekte aus dem Bereich der Simulation von Wärmeübertragungsprozessen mit Excel-VBA vorgestellt. - Thermische Behandlung hochviskoser Fruchtzubereitungen, verschiedene Projekte und Kooperationen mit der Zentis GmbH & Co. KG, Aachen (J. Becker, U. Feuerriegel, G. Wersch). - Untersuchung des dynamischen Verhaltens von dampfbeheizten Ethylen-Verdampfern. Projekt mit der TGE Gas Engineering GmbH, Bonn (M. Ecker, U. Feuerriegel, U. Hoffmann, S. Wittenhorst). - Dynamische Simulation des axialen Temperaturverlaufs von elektrisch beheizten Rohrreaktoren. Kooperation mit dem Institut für Chemische Verfahrenstechnik, TU Clausthal (U. Feuerriegel, U. Kunz, M. Pook, S. Wittenhorst).
KW - Wärmeübertragung
Y1 - 2012
ER -
TY - JOUR
A1 - Fiedler, Thomas M.
A1 - Ladd, Mark E.
A1 - Bitz, Andreas
T1 - SAR Simulations & Safety
JF - NeuroImage
Y1 - 2017
U6 - https://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 - https://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 - 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 - https://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 - Orzada, Stephan
A1 - Flöser, Martina
A1 - Rietsch, Stefan H. G.
A1 - Quick, Harald H.
A1 - Ladd, Mark E.
A1 - Bitz, Andreas
T1 - Performance analysis of integrated RF microstrip transmit antenna arrays with high channel count for body imaging at 7 T
JF - NMR in Biomedicine
N2 - The aim of the current study was to investigate the performance of integrated RF
transmit arrays with high channel count consisting of meander microstrip antennas
for body imaging at 7 T and to optimize the position and number of transmit ele-
ments. RF simulations using multiring antenna arrays placed behind the bore liner
were performed for realistic exposure conditions for body imaging. Simulations were
performed for arrays with as few as eight elements and for arrays with high channel
counts of up to 48 elements. The B1+ field was evaluated regarding the degrees of
freedom for RF shimming in the abdomen. Worst-case specific absorption rate
(SARwc ), SAR overestimation in the matrix compression, the number of virtual obser-
vation points (VOPs) and SAR efficiency were evaluated. Constrained RF shimming
was performed in differently oriented regions of interest in the body, and the devia-
tion from a target B1+ field was evaluated. Results show that integrated multiring
arrays are able to generate homogeneous B1+ field distributions for large FOVs, espe-
cially for coronal/sagittal slices, and thus enable body imaging at 7 T with a clinical
workflow; however, a low duty cycle or a high SAR is required to achieve homoge-
neous B1+ distributions and to exploit the full potential. In conclusion, integrated
arrays allow for high element counts that have high degrees of freedom for the pulse
optimization but also produce high SARwc , which reduces the SAR accuracy in the
VOP compression for low-SAR protocols, leading to a potential reduction in array
performance. Smaller SAR overestimations can increase SAR accuracy, but lead to a
high number of VOPs, which increases the computational cost for VOP evaluation
and makes online SAR monitoring or pulse optimization challenging. Arrays with
interleaved rings showed the best results in the study.
KW - body imaging at UHF MRI
KW - integrated transmit coil arrays
KW - VOP compression
Y1 - 2021
U6 - https://doi.org/10.1002/nbm.4515
SN - 0952-3480 (ISSN)
SN - 1099-1492 (eISSN)
VL - 34
IS - 7
PB - Wiley
CY - Weinheim
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 transmit array 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 - https://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 - CHAP
A1 - Finger, Felix
A1 - Khalsa, R.
A1 - Kreyer, Jörg
A1 - Mayntz, Joscha
A1 - Braun, Carsten
A1 - Dahmann, Peter
A1 - Esch, Thomas
A1 - Kemper, Hans
A1 - Schmitz, O.
A1 - Bragard, Michael
T1 - An approach to propulsion system modelling for the conceptual design of hybrid-electric general aviation aircraft
T2 - Deutscher Luft- und Raumfahrtkongress 2019, 30.9.-2.10.2019, Darmstadt
N2 - In this paper, an approach to propulsion system modelling for hybrid-electric general aviation aircraft is presented. Because the focus is on general aviation aircraft, only combinations of electric motors and reciprocating combustion engines are explored. Gas turbine hybrids will not be considered. The level of the component's models is appropriate for the conceptual design stage. They are simple and adaptable, so that a wide range of designs with morphologically different propulsive system architectures can be quickly compared. Modelling strategies for both mass and efficiency of each part of the propulsion system (engine, motor, battery and propeller) will be presented.
Y1 - 2019
ER -
TY - JOUR
A1 - Foltz, Christian
A1 - Schneider, Nicole
A1 - Wolf, Martin R.
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 - https://doi.org/10.1007/978-3-540-70552-9_21
SP - 527
EP - 554
PB - Springer
CY - Berlin
ER -
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 - https://doi.org/10.1667/RR3424.1
SN - 1938-5404
VL - 164
IS - 3
SP - 258
EP - 269
ER -
TY - JOUR
A1 - Frauenrath, Tobias
A1 - Fuchs, Katharina
A1 - Dieringer, Matthias A.
A1 - Özerdem, Celal
A1 - Patel, Nishan
A1 - Renz, Wolfgang
A1 - Greiser, Andreas
A1 - Elgeti, Thomas
A1 - Niendorf, Thoralf
T1 - Detailing the use of magnetohydrodynamic effects for synchronization of MRI with the cardiac cycle: A feasibility study
JF - Journal of Magnetic Resonance Imaging
N2 - 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.
Y1 - 2012
U6 - https://doi.org/10.1002/jmri.23634
SN - 1522-2586
VL - 36
IS - 2
SP - 364
EP - 372
PB - Wiley-Liss
CY - New York
ER -
TY - JOUR
A1 - Frauenrath, Tobias
A1 - Hezel, Fabian
A1 - Renz, Wolfgang
A1 - de Geyer d'Orth, Thibaut
A1 - Dieringer, Matthias
A1 - von Knobelsdorf-Brenkenhoff, Florian
A1 - Prothmann, Marcel
A1 - Schulz-Menger, Jeanette
A1 - Niendorf, Thoralf
T1 - Acoustic cardiac triggering: a practical solution for synchronization and gating of cardiovascular magnetic resonance at 7 Tesla
JF - Journal of Cardiovascular Magnetic Resonance
N2 - Background
To demonstrate the applicability of acoustic cardiac triggering (ACT) for imaging of the heart at ultrahigh magnetic fields (7.0 T) by comparing phonocardiogram, conventional vector electrocardiogram (ECG) and traditional pulse oximetry (POX) triggered 2D CINE acquisitions together with (i) a qualitative image quality analysis, (ii) an assessment of the left ventricular function parameter and (iii) an examination of trigger reliability and trigger detection variance derived from the signal waveforms.
Results
ECG was susceptible to severe distortions at 7.0 T. POX and ACT provided waveforms free of interferences from electromagnetic fields or from magneto-hydrodynamic effects. Frequent R-wave mis-registration occurred in ECG-triggered acquisitions with a failure rate of up to 30% resulting in cardiac motion induced artifacts. ACT and POX triggering produced images free of cardiac motion artefacts. ECG showed a severe jitter in the R-wave detection. POX also showed a trigger jitter of approximately Δt = 72 ms which is equivalent to two cardiac phases. ACT showed a jitter of approximately Δt = 5 ms only. ECG waveforms revealed a standard deviation for the cardiac trigger offset larger than that observed for ACT or POX waveforms.
Image quality assessment showed that ACT substantially improved image quality as compared to ECG (image quality score at end-diastole: ECG = 1.7 ± 0.5, ACT = 2.4 ± 0.5, p = 0.04) while the comparison between ECG vs. POX gated acquisitions showed no significant differences in image quality (image quality score: ECG = 1.7 ± 0.5, POX = 2.0 ± 0.5, p = 0.34).
Conclusions
The applicability of acoustic triggering for cardiac CINE imaging at 7.0 T was demonstrated. ACT's trigger reliability and fidelity are superior to that of ECG and POX. ACT promises to be beneficial for cardiovascular magnetic resonance at ultra-high field strengths including 7.0 T.
KW - Interval Time Series
KW - Image Quality Score
KW - Image Quality Assessment
KW - Sound Pressure Level
KW - Cardiovascular Magnetic Resonance
Y1 - 2010
U6 - https://doi.org/10.1186/1532-429X-12-67
SN - 1532-429X
VL - 12
IS - 1
PB - Elsevier
CY - Amsterdam
ER -
TY - PAT
A1 - Frauenrath, Tobias
A1 - Niendorf, Thoralf
T1 - MRT-Vorrichtung und Verfahren zum Betreiben einer MRT-Vorrichtung
T1 - Magnetic resonance tomography (MRT) apparatus and method of operating a magnetic resonance (MR) apparatus
T1 - Appareil de tomographie par résonance magnétique et procédé de fonctionnement d'un appareil à résonance magnétique
N2 - 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.
Y1 - 2012
ER -
TY - JOUR
A1 - Frauenrath, Tobias
A1 - Niendorf, Thoralf
A1 - Kob, Malte
T1 - Acoustic method for synchronization of Magnetic Resonance Imaging (MRI)
JF - Acta Acustica
N2 - Magnetic Resonance Imaging (MRI) of moving organs requires synchronization with physiological motion or flow, which dictate the viable window for data acquisition. To meet this challenge, this study proposes an acoustic gating device (ACG) that employs acquisition and processing of acoustic signals for synchronization while providing MRI compatibility, immunity to interferences with electro-magnetic and acoustic fields and suitability for MRI at high magnetic field strengths. The applicability and robustness of the acoustic gating approach is examined in a pilot study, where it substitutes conventional ECG-gating for cardiovascular MR. The merits and limitations of the ACG approach are discussed. Implications for MR imaging in the presence of physiological motion are considered including synchronization with other structure- or motion borne sounds.
Y1 - 2008
U6 - https://doi.org/10.3813/AAA.918017
SN - 1861-9959
VL - 94
IS - 1
SP - 148
EP - 155
PB - Hirzel
CY - Stuttgart
ER -
TY - GEN
A1 - Frauenrath, Tobias
A1 - Pfeiffer, Harald
A1 - Hezel, Fabian
A1 - Dieringer, Matthias A.
A1 - Winter, Lukas
A1 - Gräßl, Andreas
A1 - Santoro, Davide
A1 - Özerdem, Celal
A1 - Renz, Wolfgang
A1 - Greiser, Andreas
A1 - Niendorf, Thoralf
T1 - Lessons learned from cardiac MRI at 7.0 T: LV function assessment at 3.0 T using local multi-channel transceiver coil arrays
T2 - 2012 ISMRM Annual Meeting Proceedings
N2 - 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.
Y1 - 2012
SN - 1545-4428
N1 - ISMRM 20th Annual Meeting & Exhibition, 5-11 May 2012, Melbourne, Australia
ER -
TY - JOUR
A1 - Fuchs, Britta
A1 - Ritz, Thomas
T1 - Absatzkanäle kaum verknüpft
JF - IT-Mittelstand : IT-Business im Mittelstand
Y1 - 2011
VL - 2011
IS - 9
SP - 16
PB - Medienhaus-Verlag
CY - Bergisch-Gladbach
ER -
TY - CHAP
A1 - Fuchs, Britta
A1 - Ritz, Thomas
T1 - Usability for Blended Shopping - Solving Major Flaws by Applying Usability Engineering and Proven Integration Technologies
T2 - Proceedings of the 11th International Conference on e-Business, ICE-B 2014, Vienna, Austria
Y1 - 2014
SN - 978-989-758-043-7
U6 - https://doi.org/10.5220/0005113502160223
SP - 216
EP - 223
ER -
TY - CHAP
A1 - Fuchs, Britta
A1 - Ritz, Thomas
A1 - Strauch, Jakob
ED - Obaidat, Mohammad S.
T1 - Usability of mobile applications : dissemination of usability engineering in small and medium enterprises
T2 - 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)]
Y1 - 2012
SN - 978-989-8565-23-5
N1 - Nebentitel: DCNET; ICE-B; OPTICS
SP - 272
EP - 277
PB - SciTePress
CY - [Lissabon]
ER -
TY - CHAP
A1 - Galdi, Chiara
A1 - Hartung, Frank
A1 - Dugelay, Jean-Luc
T1 - Socrates: A database of realistic data for source camera recognition on smartphones
T2 - Proceedings of the 8th International Conference on Pattern Recognition Applications and Methods - Volume 1: ICPRAM
Y1 - 2019
SN - 978-989-758-351-3
U6 - https://doi.org/10.5220/0007403706480655
SP - 648
EP - 655
ER -
TY - CHAP
A1 - Galdi, Chiara
A1 - Hartung, Frank
A1 - Dugelay, Jean-Luc
T1 - Videos versus still images: Asymmetric sensor pattern noise comparison on mobile phones
T2 - Electronic Imaging
N2 - Nowadays, the most employed devices for recoding videos or capturing images are undoubtedly the smartphones. Our work investigates the application of source camera identification on mobile phones. We present a dataset entirely collected by mobile phones. The dataset contains both still images and videos collected by 67 different smartphones. Part of the images consists in photos of uniform backgrounds, especially collected for the computation of the RSPN. Identifying the source camera given a video is particularly challenging due to the strong video compression. The experiments reported in this paper, show the large variation in performance when testing an highly accurate technique on still images and videos.
KW - Image Forensics
KW - Mobile Phones
KW - Image Database
Y1 - 2017
U6 - https://doi.org/10.2352/ISSN.2470-1173.2017.7.MWSF-331
SN - 2470-1173
N1 - IS&T International Symposium on Electronic Imaging 2017
Media Watermarking, Security, and Forensics 2017
SP - 100
EP - 103
PB - Society for Imaging Science and Technology
CY - Springfield, Virginia
ER -
TY - BOOK
A1 - Galley, Birgit
A1 - Minoggio, Ingo
A1 - Schuba, Marko
A1 - Bischoff, Barbara
A1 - Höfken, Hans-Wilhelm
T1 - Unternehmenseigene Ermittlungen : Recht - Kriminalistik - IT
Y1 - 2016
SN - 978-3-503-16531-5
PB - Erich Schmidt Verlag
CY - Berlin
ER -
TY - CHAP
A1 - Gebhardt, Andreas
A1 - Ritz, Thomas
A1 - Siekmann, Kirsten
A1 - Wallenborn, Ramona
ED - Demmer, Axel
T1 - Additive manufacturing businesses in the process chain of individualized mass products
T2 - DDMC 2014 : Proceedings of the Fraunhofer Direct Digital Manufacturing Conference
Y1 - 2014
SN - 978-3-8396-9128-1 (E-Book)
PB - Fraunhofer
CY - Stuttgart
ER -
TY - THES
A1 - Gligorevic, Snjezana
T1 - Entzerrung schnell zeitveränderlicher Kanäle. (Fortschritt-Berichte VDI : Reihe 10, Informatik, Kommunikation ; Nr. 747)
Y1 - 2004
SN - 3-18-374710-3
N1 - Zugl.: Ulm, Techn. Univ., Diss. 2004
PB - VDI-Verl.
CY - Düsseldorf
ER -
TY - CHAP
A1 - Gligorevic, Snjezana
T1 - Joint channel estimation and equalization for fast time-variant multipath channels
T2 - Proceedings / 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications : PIMRC 2002 : Lisboa, Portugal, September 15 - 18, 2002
Y1 - 2002
SN - 0-7803-7589-0
SP - 1127
EP - 1130
ER -
TY - JOUR
A1 - Gligorevic, Snjezana
T1 - Joint channel estimation and equalisation of fast time-varying frequency-selective channels
JF - European transactions on telecommunications
Y1 - 2008
SN - 1541-8251; 2161-3915; 1120-3862; 1124-318X
VL - Vol. 19
IS - Iss. 1
SP - 1
EP - 13
ER -
TY - JOUR
A1 - Gligorevic, Snjezana
T1 - Airport surface propagation channel in the C-Band: measurements and modeling
JF - IEEE transactions on antennas and propagation
Y1 - 2013
SN - 0018-926x
VL - Vol. 61
IS - Iss. 9
SP - 4792
EP - 4802
PB - IEEE
CY - New York
ER -
TY - CHAP
A1 - Gligorevic, Snjezana
T1 - Stochastic modeling of non-stationary channels
T2 - 7th European Conference on Antennas and Propagation (EuCAP) : 8 - 12 April 2013, Gothenburg, Sweden
Y1 - 2013
SN - 978-1-4673-2187-7 ; 978-88-907018-1-8
SP - 1677
EP - 1681
PB - IEEE
CY - Piscataway, NJ
ER -
TY - CHAP
A1 - Gligorevic, Snjezana
A1 - Bott, Rainer
A1 - Sorger, Ulrich
ED - Fazel, Khaled
T1 - Equalization for multi-carrier systems in time-varying channels
T2 - Multi-carrier spread-spectrum for future generation wireless systems : fourth international workshop, Germany, September 17-19, 2003
Y1 - 2004
SN - 1402018371
SP - 251
EP - 258
ER -
TY - CHAP
A1 - Gligorevic, Snjezana
A1 - Brandes, Sinja
A1 - Cosovic, I.
A1 - Schnell, Michael
T1 - B-VHF, ein 'Overlay'-System für die ATC Kommunikation im VHF Band
T2 - Motto: Luft- und Raumfahrt - Grenzen überwinden, Horizonte erweitern : Deutscher Luft- und Raumfahrtkongress 2005, Friedrichshafen, 26. bis 29. September 2005
Y1 - 2005
SP - 951
EP - 958
PB - DGLR
CY - Bonn
ER -
TY - CHAP
A1 - Gligorevic, Snjezana
A1 - Epple, Ulrich
A1 - Schnell, Michael
T1 - The LDACS1 physical layer design
T2 - Future aeronautical communications
Y1 - 2011
SN - 978-953-307-625-6
SP - 317
EP - 332
PB - Intech
CY - London
ER -
TY - CHAP
A1 - Gligorevic, Snjezana
A1 - Jost, T.
A1 - Walter, M.
T1 - Scatterer based airport surface channel model
T2 - IEEE/AIAA 28th Digital Avionics Systems Conference : DASC '09 ; 23 - 29 [i.e. 25 - 29] Oct. 2009, Orlando, Fla.
Y1 - 2009
SN - 978-1-4244-4078-8
SP - 4C2-1
EP - 4C2-10
ER -
TY - CHAP
A1 - Gligorevic, Snjezana
A1 - Pulini, Paola
T1 - Simplified airport surface channel model based on the WSSUS assumption
T2 - 2010 Integrated Communications, Navigation and Surveillance Conference (ICNS 2010) : Herndon, Virginia, USA, 11 - 13 May 2010
Y1 - 2010
SN - 978-1-4244-7457-8
SN - 2155-4943
SP - F2-1
EP - F2-11
ER -
TY - CHAP
A1 - Gligorevic, Snjezana
A1 - Schneckenburger, N.
A1 - Franzen, N.
A1 - Schnell, Michael
A1 - Müller, S.
A1 - Günzel, H.
T1 - L-Band compatibility of LDACS1
T2 - 3rd CEAS Air and Space Conference, 24 - 28 October 2011, Venezia, Italy
Y1 - 2011
SP - 1
EP - 8
ER -
TY - CHAP
A1 - Gligorevic, Snjezana
A1 - Sorger, Ulrich
T1 - A new approach to tracking time-variant channels
T2 - Proceedings / 5th International Symposium on Wireless Personal Multimedia Communications : WPMC : October 27 - 30, 2002, Honolulu, Hawaii ; vol. 3
Y1 - 2002
SN - 0-7803-7442-8
SN - 1347-6890
SP - 1342
EP - 1345
ER -
TY - CHAP
A1 - Gligorevic, Snjezana
A1 - Zierhut, R.
A1 - Jost, T.
A1 - Wang, Wei
T1 - Airport channel measurements at 5.2GHz
T2 - 3rd European Conference on Antennas and Propagation : (EuCAP) ; Berlin, Germany, 23 - 27 March 2009
Y1 - 2009
SN - 978-1-4244-4753-4 ; 978-3-00-024573-2
SP - 877
EP - 881
ER -
TY - CHAP
A1 - Goeckel, Tom
A1 - Schiffer, Stefan
A1 - Wagner, Hermann
A1 - Lakemeyer, Gerhard
T1 - The Video Conference Tool Robot ViCToR
T2 - Intelligent Robotics and Applications : 8th International Conference, ICIRA 2015, Portsmouth, UK, August 24-27, 2015, Proceedings, Part II
N2 - We present a robotic tool that autonomously follows a conversation to enable remote presence in video conferencing. When humans participate in a meeting with the help of video conferencing tools, it is crucial that they are able to follow the conversation both with acoustic and visual input. To this end, we design and implement a video conferencing tool robot that uses binaural sound source localization as its main source to autonomously orient towards the currently talking speaker. To increase robustness of the acoustic cue against noise we supplement the sound localization with a source detection stage. Also, we include a simple onset detector to retain fast response times. Since we only use two microphones, we are confronted with ambiguities on whether a source is in front or behind the device. We resolve these ambiguities with the help of face detection and additional moves. We tailor the system to our target scenarios in experiments with a four minute scripted conversation. In these experiments we evaluate the influence of different system settings on the responsiveness and accuracy of the device.
Y1 - 2015
SN - 978-3-319-22876-1
U6 - https://doi.org/10.1007/978-3-319-22876-1_6
N1 - Lecture Notes in Computer Science ; 9245
SP - 61
EP - 73
PB - Springer
ER -
TY - PAT
A1 - Gollewski, Torsten
A1 - Lange, Robert
A1 - Ringbeck, Thorsten
A1 - Hess, Holger
A1 - Buxbaum, Bernd
T1 - Verfahren und Vorrichtung zur Laufzeitsensitiven Messung eines Signals [Offenlegungsschrift / Europäische Patentschrift]
T1 - Apparatus for delay-sensitive measurement of a signal
T1 - Dispositif pour le mesurage sensitif au temps de transit d'un signal
Y1 - 2006
PB - Deutsches Patent- und Markenamt / Europäisches Patentamt
CY - München / Den Hague
ER -
TY - CHAP
A1 - Granat, Andreas
A1 - Höfken, Hans-Wilhelm
A1 - Schuba, Marko
T1 - Intrusion Detection of the ICS Protocol EtherCAT
N2 - Control mechanisms like Industrial Controls Systems (ICS) and its subgroup SCADA (Supervisory Control and Data Acquisition) are a prerequisite to automate industrial processes. While protection of ICS on process management level is relatively straightforward – well known office IT security mechanisms can be used – protection on field bus level is harder to achieve as there are real-time and production requirements like 24x7 to consider. One option to improve security on field bus level is to introduce controls that help to detect and to react on attacks. This paper introduces an initial set of intrusion detection mechanisms for the field bus protocol EtherCAT. To this end existing Ethernet attack vectors including packet injection and man-in-the-middle attacks are tested in an EtherCAT environment, where they could interrupt the EtherCAT network and may even cause physical damage. Based on the signatures of such attacks, a preprocessor and new rule options are defined for the open source intrusion detection system Snort demonstrating the general feasibility of intrusion detection on field bus level.
Y1 - 2017
N1 - International Conference on Computer, Network Security and Communication Engineering (CNSCE 2017), March 26-27, 2017, Bangkok, Thailand
SP - 1
EP - 5
ER -
TY - JOUR
A1 - Grande, Marion
A1 - Meffert, Elisabeth
A1 - Schoenberger, Eva
A1 - Jung, Stefanie
A1 - Frauenrath, Tobias
A1 - Huber, Walter
A1 - Hussmann, Katja
A1 - Moormann, Mareike
A1 - Heim, Stefan
T1 - From a concept to a word in a syntactically complete sentence: An fMRI study on spontaneous language production in an overt picture description task
JF - NeuroImage
N2 - 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.
Y1 - 2012
U6 - https://doi.org/10.1016/j.neuroimage.2012.03.087
SN - 1522-2586
VL - 61
IS - 3
SP - 702
EP - 714
PB - Elsevier
CY - Amsterdam
ER -
TY - BOOK
A1 - Gromov, Viacheslav
A1 - Hüning, Felix
T1 - Schnelleinstieg mit dem Renesas RL78/G14 Starter Kit
Y1 - 2015
SN - 978-3-645-10157-8
PB - Franzis
CY - Poing
ER -
TY - CHAP
A1 - Grothof, M.
A1 - Schwarte, Rudolf
A1 - Buxbaum, Bernd
A1 - Ringbeck, Thorsten
ED - Wagner, Elmar
T1 - Product monitoring with MSM-PMD-Array
T2 - Proceedings / OPTO 2002 : an event of the Association for Sensor Technology AMA ; 14 - 16 May 2002, Exhibition Centre Erfurt, Germany / International Conference Optoelectronics, Optical Sensors & Measuring Techniques
Y1 - 2002
N1 - OPTO <5, 2002, Erfurt> ; International Conference Optoelectronics, Optical Sensors & Measuring Techniques
SP - 41
EP - 47
PB - AMA Service GmbH
CY - Wunsdorf
ER -
TY - CHAP
A1 - Grund, Raphael M.
A1 - Altherr, Lena
ED - Reiff-Stephan, Jörg
ED - Jäkel, Jens
ED - Schwarz, André
T1 - Development of an open source energy disaggregation tool for the home automation platform Home Assistant
T2 - Tagungsband AALE 2023 : mit Automatisierung gegen den Klimawandel
N2 - In order to reduce energy consumption of homes, it is important to make transparent which devices consume how much energy. However, power consumption is often only monitored aggregated at the house energy meter. Disaggregating this power consumption into the contributions of individual devices can be achieved using Machine Learning. Our work aims at making state of the art disaggregation algorithms accessibe for users of the open source home automation platform Home Assistant.
KW - Home Automation Platform
KW - Home Assistant
KW - Open Source
KW - Machine Learning
KW - Energy Disaggregation
Y1 - 2023
SN - 978-3-910103-01-6
U6 - https://doi.org/10.33968/2023.02
N1 - 19. AALE-Konferenz. Luxemburg, 08.03.-10.03.2023.
BTS Connected Buildings & Cities Luxemburg
(Tagungsband unter https://doi.org/10.33968/2023.01)
SP - 11
EP - 20
PB - le-tex publishing services GmbH
CY - Leipzig
ER -
TY - JOUR
A1 - Gräßl, Andreas
A1 - Renz, Wolfgang
A1 - Hezel, Fabian
A1 - Dieringer, Matthias A.
A1 - Winter, Lukas
A1 - Özerdem, Celal
A1 - Rieger, Jan
A1 - Kellmann, Peter
A1 - Santoro, Davide
A1 - Lindel, Tomasz D.
A1 - Frauenrath, Tobias
A1 - Pfeiffer, Harald
A1 - Niendorf, Thoralf
T1 - Modular 32-channel transceiver coil array for cardiac MRI at 7.0T
JF - Magnetic Resonance in Medicine
N2 - Purpose
To design and evaluate a modular transceiver coil array with 32 independent channels for cardiac MRI at 7.0T.
Methods
The modular coil array comprises eight independent building blocks, each containing four transceiver loop elements. Numerical simulations were used for B1+ field homogenization and radiofrequency (RF) safety validation. RF characteristics were examined in a phantom study. The array's suitability for accelerated high spatial resolution two-dimensional (2D) FLASH CINE imaging of the heart was examined in a volunteer study.
Results
Transmission field adjustments and RF characteristics were found to be suitable for the volunteer study. The signal-to-noise intrinsic to 7.0T together with the coil performance afforded a spatial resolution of 1.1 × 1.1 × 2.5 mm3 for 2D CINE FLASH MRI, which is by a factor of 6 superior to standardized CINE protocols used in clinical practice at 1.5T. The 32-channel transceiver array supports one-dimensional acceleration factors of up to R = 4 without impairing image quality significantly.
Conclusion
The modular 32-channel transceiver cardiac array supports accelerated and high spatial resolution cardiac MRI. The array is compatible with multichannel transmission and provides a technological basis for future clinical assessment of parallel transmission techniques at 7.0T.
Y1 - 2013
U6 - https://doi.org/10.1002/mrm.24903
SN - 1522-2594
VL - 72
IS - 1
SP - 276
EP - 290
PB - Wiley-Liss
CY - New York
ER -
TY - GEN
A1 - Gräßl, Andreas
A1 - Renz, Wolfgang
A1 - Hezel, Fabian
A1 - Frauenrath, Tobias
A1 - Pfeiffer, Harald
A1 - Hoffmann, Werner
A1 - Kellmann, Peter
A1 - Martin, Conrad
A1 - Niendorf, Thoralf
T1 - Design, evaluation and application of a modular 32 channel transmit/receive surface coil array for cardiac MRI at 7T
T2 - 2012 ISMRM Annual Meeting Proceedings
N2 - 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.
Y1 - 2012
SN - 1545-4428
N1 - ISMRM 20th Annual Meeting & Exhibition, 5-11 May 2012, Melbourne, Australia
ER -
TY - JOUR
A1 - Gspandl, Stephan
A1 - Pill, Ingo
A1 - Reip, Michael
A1 - Steinbauer, Gerald
A1 - Ferrein, Alexander
T1 - Belief Management for High-Level Robot Programs
JF - Proceedings of the Twenty-Second International Joint Conference on Artificial Intelligence [electronic resource] : Barcelona, Catalonia, Spain, 16 - 22 July 2011 / sponsored by International Joint Conferences on Artificial Intelligence (IJCAI) and the Association for the Advancement of Artificial Intelligence (AAAI). Ed. by Toby Walsh
Y1 - 2011
N1 - International Joint Conference on Artificial Intelligence ; (22 : ; 2011.07.16-22 : ; Barcelona, Spain) ; IJCAI ; (22 : ; 2011.07.16-22 : ; Barcelona, Spain)
SP - 900
EP - 905
ER -
TY - BOOK
A1 - Gunnar, Auth
A1 - Barton, Thomas
A1 - Beigel, Stefan
A1 - Bensberg, Frank
A1 - Brehm, Lars
A1 - Wolf, Martin R.
ED - Barton, Thomas
ED - Herrmann, Frank
ED - Meister, Vera G.
ED - Müller, Christian
ED - Seel, Christian
T1 - Prozesse, Technologie, Anwendungen, Systeme und Management 2017
BT - Angewandte Forschung in der Wirtschaftsinformatik. Tagungsband zur 30. AKWI-Jahrestagung vom 17.09.2017 bis 20.09.2017 an der Hochschule Aschaffenburg / Arbeitskreis Wirtschaftsinformatik an Fachhochschulen (AKWI)
Y1 - 2017
SN - 978-3-944330-56-3
PB - Mana-Buch
CY - Heide
ER -
TY - JOUR
A1 - Haag, S.
A1 - Zontar, D.
A1 - Schleupen, Josef
A1 - Müller, T.
A1 - Brecher, C.
T1 - Chain of refined perception in self-optimizing assembly of micro-optical systems
JF - Journal of sensors and sensor systems
N2 - Today, the assembly of laser systems requires a large share of manual operations due to its complexity regarding the optimal alignment of optics. Although the feasibility of automated alignment of laser optics has been shown in research labs, the development effort for the automation of assembly does not meet economic requirements – especially for low-volume laser production. This paper presents a model-based and sensor-integrated assembly execution approach for flexible assembly cells consisting of a macro-positioner covering a large workspace and a compact micromanipulator with camera attached to the positioner. In order to make full use of available models from computer-aided design (CAD) and optical simulation, sensor systems at different levels of accuracy are used for matching perceived information with model data. This approach is named "chain of refined perception", and it allows for automated planning of complex assembly tasks along all major phases of assembly such as collision-free path planning, part feeding, and active and passive alignment. The focus of the paper is put on the in-process image-based metrology and information extraction used for identifying and calibrating local coordinate systems as well as the exploitation of that information for a part feeding process for micro-optics. Results will be presented regarding the processes of automated calibration of the robot camera as well as the local coordinate systems of part feeding area and robot base.
Y1 - 2014
U6 - https://doi.org/10.5194/jsss-3-87-2014
SN - 2194-878X
VL - 3
IS - 1
SP - 87
EP - 95
PB - Copernicus Publ.
CY - Göttingen
ER -
TY - CHAP
A1 - Hadinejad-Mahram, Hafez
A1 - Gligorevic, Snjezana
A1 - Ritscher, Matthias
T1 - Joint iterative channel estimation and parallel interference cancellation for coded DS-CDMA
T2 - Proceeding of the International Conference on Telecommunications 2002 : [Beijing, 23 - 26 June 2002]. Vol. 2
Y1 - 2002
SP - 566
EP - 570
ER -
TY - JOUR
A1 - Hagebeuker, Bianca
A1 - Lange, Robert
A1 - Ringbeck, Thorsten
T1 - Bildverarbeitung mit der dritten Dimension : wenn die Pixel auch Laufzeiten auswerten
JF - Sensor-Report : Sensorik, Messtechnik, Bildverarbeitung, Fabrikautomation. - 2004, H. 2
Y1 - 2004
SN - 0179-9592
SP - 11
EP - 17
PB - Rek & Thomas
CY - St. Gallen
ER -
TY - CHAP
A1 - Hagebeuker, Bianca
A1 - Ringbeck, Thorsten
A1 - Frydlewicz, Paul
A1 - Jesorsky, Oliver
A1 - Sünkel, Thomas
ED - Grote, Caspar
T1 - PMD-Sensoren als Schlüsselkomponenten für die mehrdimensionale Umfelderfassung des Fahrzeuginnenraums
T2 - Begleittexte zum Entwicklerforum KFZ-Elektronik & FlexRay Solution Day : 15.Mai 2007, Ludwigsburg
Y1 - 2007
N1 - Entwicklerforum Kfz-Elektronik <2007, Ludwigsburg> ; FlexRay Solution Day <2007, Ludwigsburg>
SP - 287
EP - 296
PB - WEKA-Fachzeitschr.-Verl.
CY - Poing
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
T1 - INGMEDIA - Lernsoftware für technische und physikalische Praktika in Ingenieurstudiengängen
JF - E-Learning : Tagungsband ; NMB-Projekte in den Ingenieurwissenschaften ; Workshop der ingenieurwissenschaftlichen Projekte im bmb+f-Förderprogramm "Neue Medien in der Bildung" am 25. und 26. Juni 2003 an der Hochschule Anhalt in Dessau / Hrsg.: Stephan Pi
Y1 - 2003
N1 - Workshop E-Learning: NMB-Projekte in den Ingenieurwissenschaften <2003, Dessau>
SP - 64
EP - 69
PB - Hochschule Anhalt
CY - Dessau
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
T1 - INGMEDIA - E-Learning für Laborpraktika
JF - Evaluation von E-Learning : Zielrichtungen, methodologische Aspekte, Zukunftsperspektiven / Dorothee M. Meister ... (Hrsg.)
Y1 - 2004
SN - 3-8309-1311-7
N1 - Medien in der Wissenschaft ; 25
SP - 217
EP - 222
PB - Waxmann
CY - Münster [u.a.]
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
T1 - Loss mechanisms and domain stabilization in doped BaTiO₃
JF - Journal of Physics C: Solid State Physics
Y1 - 1978
SN - 0022-3719
U6 - https://doi.org/10.1088/0022-3719/11/15/031
VL - 11
IS - 15
SP - 3333
EP - 3344
PB - n.a.
CY - London
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
T1 - Electrical properties of acceptor-doped BaTiO3 ceramic. Hagemann, H. J.
JF - Berichte der Deutschen Keramischen Gesellschaft. 55 (1978)
Y1 - 1978
SN - 0365-9542
SP - 353
EP - 355
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
T1 - Reduction of hysteresis losses of ferroelectric BaTiO3. Hagemann, H. J.
JF - Ferroelectrics. 22 (1978)
Y1 - 1978
SN - 0015-0193
SP - 743
EP - 743
ER -
TY - BOOK
A1 - Hagemann, Hans-Jürgen
T1 - Akzeptorionen in BaTiO3 und SrTiO3 und ihre Auswirkungen auf die Eigenschaften von Titanatkeramiken
Y1 - 1980
N1 - Aachen, Techn.Hochsch., Fak.f.Elektrotechnik, Diss.
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
T1 - Störstellengleichgewichte in eisendotierten Titanaten. Hagemann, H. J.
JF - Philips - Unsere Forschung in Deutschland / Hrsg.: Philips Forschungslaboratorium GmbH Aachen und Hamburg. 4 (1989)
Y1 - 1989
SP - 170
EP - 172
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Bachmann, P. K.
A1 - Lade, H.
A1 - Leers, D.
T1 - Thermal properties of C/H-, C/H/O-, C/H/N- and C/H/X-grown polycrystalline CVD diamond. P. K. Bachmann, H. J. Hagemann, H. Lade, ...
JF - Diamond and Related Material. Vol 4. (1995), H. Issue 5-6
Y1 - 1995
N1 - abstract online:
SP - 820
EP - 826
PB - Elsevier Science
CY - New York, NY [u.a.]
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Bachmann, P. K.
A1 - Lade, H.
A1 - Leers, D.
T1 - Influence of the gas phase on diamond deposition and diamond properties. Bachmann, P. K.; Hagemann, H.J.; Lade, H.; Leers, D.; Picht, F.; Wiechert, D. U.
JF - Advanced materials '94 : proceedings of the NIRIM International Symposium on Advanced Materials '94, Tsukuba, Japan, March 13 - 17, 1994 / National Institute for Research in Inorganic Materials. Ed. by M. Kamo
Y1 - 1994
N1 - NIRIM International Symposium on Advanced Materials ; <1994, Tsukuba>
SP - 115
EP - 120
PB - International Communications Specialists, Inc.
CY - Tokyo
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Bachmann, P.K.
A1 - Lade, H.
A1 - Leers, D.
T1 - CVD Diamond Growth: Gas Compositions and Film Properties / P.K. Bachmann, H.J. Hagemann, H. Lade, D. Leers, D.U. Wiechert and H. Wilson
JF - Advanced materials '94 : proceedings of the NIRIM International Symposium on Advanced Materials '94, Tsukuba, Japan, March 13 - 17, 1994 / National Institute for Research in Inorganic Materials. Ed. by M. Kamo ...
Y1 - 1994
N1 - NIRIM International Symposium on Advanced Materials ; 1994 (Tsukuba) : 1994.03.13-17
SP - 115
EP - 120
PB - International Communications Specialists
CY - Tokyo
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Bachmann, P.K.
A1 - Lade, H.
A1 - Leers, D.
T1 - Diamond chemical vapor deposition: gas compositions and film properties / Bachmann, P.K.; Hagemann, H.-J.; Lade, H; Leers, D.; Picht, F.; Wiechert, D.U.; Wilson, H.
JF - Diamond, SiC and nitride wide bandgap semiconductors : symposium held April 4 - 8, 1994, San Francisco, California, U.S.A. / ed.: Calvin H. Carter, Jr. ...
Y1 - 1994
SN - 1-55899-239-1
N1 - Materials Research Society symposium proceedings ; 339
SP - 267
EP - 277
CY - Pittsburgh, Penn.
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Backhaus, U.
A1 - Goessner, S.
T1 - Collaborative eLearning Concepts for University Level Online Laboratory Courses in Engineering. U. Backhaus, S. Goessner, H. J. Hagemann
JF - Proceedings Online Educa Berlin: 8th International Conference on Technology Supported Learning & Training. 2002
Y1 - 2002
N1 - Online Educa <2002, Berlin>
SP - 62
EP - 66
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Breitschuh, S.
A1 - Graber, S.
A1 - Schmitz, Günter
T1 - Internet Laboratory Courses with Remote Access and Control of Real Measurements on Sensors and Electronic Components
JF - Mechatronics & Robotics 2004 : Aachen, Germany, September 13 - 15, 2004 / [APS - European Centre for Mechatronics]. P. Drews (ed.)
Y1 - 2004
SN - 3-938153-30-X
N1 - MechRob <2004, Aachen>
SP - 1280
EP - 1284
PB - Eysoldt
CY - Aachen
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Cassidy, Wiliam D.
T1 - Diamond growth rates and quality: dependence on gas phase cpmposition / William D. Cassidy [...], Hans-Jurgen Hagemann
JF - Diamond, SiC and nitride wide bandgap semiconductors : symposium held April 4 - 8, 1994, San Francisco, California, U.S.A. / ed.: Calvin H. Carter, Jr. ....
Y1 - 1994
SN - 1-55899-239-1
N1 - Materials Research Society symposium proceedings ; 339
SP - 285
EP - 291
CY - Pittsburgh, Penn. ,
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
T1 - PCVD hybrid technology for single mode fibres. Hagemann, H. J.; Geittner, P.
JF - Proceedings : papers presented at: the 8th Annual European Fibre Optic Communications and Local Area Networks Exposition
Y1 - 1990
N1 - EFOC LAN <8, 1990, München>
SP - 67
EP - 72
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
A1 - Leers, D.
T1 - Intrinsic scattering and absorption losses of Ge- and F-doped optical fibres prepared by PCVD. Geittner, P.; Hagemann, H. J. ; Leers, D.
JF - Electronics letters : an intern. publication / The Institution of Electrical Engineers. 25 (1989), H. 7
Y1 - 1989
SN - 0013-5194
SP - 436
EP - 437
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
A1 - Lydtin, H.
A1 - Warnier, J.
T1 - Hybrid technology for large SM-fiber preforms. Geittner, P.; Hagemann, H. J.; Lydtin, H.; Warnier, J.
JF - Journal of Lightwave Technology (J-LT) / Institute of Electrical and Electronics Engineers (IEEE). 6 (1988), H. 10
Y1 - 1988
SN - 0733-8724
SP - 1451
EP - 1454
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
A1 - Mayr, W.
A1 - Opitz, J. F. A.
T1 - Folientechnologie für zukünftige keramische Vielschichtkondensatoren. Geittner, P.; Hagemann, H.-J.;Mayr, W. ; Opitz, J.F.A. ; Schmidl, B.; Warnier, J.
JF - Ceramic forum international : cfi ; Berichte der Deutschen Keramischen Gesellschaft. 8 (1993), H. 5
Y1 - 1993
SN - 0173-9913
N1 - weitere ISSN 0196-6219
SP - 5
EP - 15
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
A1 - Schnittker, W.
A1 - Warnier, J.
T1 - Abscheidegeschwindigkeiten und Prozeßausbeuten im PCVD-Verfahren. Geittner, P.; Hagemann, H. J.; Schnittker, W.; Warnier, J.; Weling, F.; Wilson, H.
JF - Philips - Unsere Forschung in Deutschland / Hrsg.: Philips Forschungslaboratorium GmbH Aachen und Hamburg. 4 (1989)
Y1 - 1989
SP - 140
EP - 143
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
A1 - Warnier, J.
A1 - Weling, F.
T1 - Reduction of geometric taper losses in the PCVD process. Geittner, P.; Hagemann, H. J.; Warnier, J.; Weling, F.; Wilson, H.
JF - Electronics letters : an intern. publication / The Institution of Electrical Engineers. 21 (1985), H. 13
Y1 - 1985
SN - 0013-5194
SP - 870
EP - 871
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
A1 - Warnier, J.
A1 - Wilson, H.
T1 - PCVD at high deposition rates. Geittner, P.; Hagemann, H. J.; Warnier, J.; Wilson, H.
JF - Journal of Lightwave Technology (J-LT) / Institute of Electrical and Electronics Engineers (IEEE). 4 (1986), H. 7
Y1 - 1986
SN - 0733-8724
SP - 818
EP - 822
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Gudat, W.
A1 - Kunz, C.
T1 - Photoabsorption of alloys of Al with transition metals V, Fe, Ni and Cu and Pr near the Al L₂,₃-edge
JF - Solid State Communications
N2 - The onset of Al 2p transitions of VAl₃, FeAl, NiAl, NiAl₃, CuAl₂, PrAl₂ and the disordered alloys V-Al (16 at % Al, 28%, 41%), Fe-Al (11%) is shifted up to 1.1 eV. New pronounced structure develops close to the onset which for NiAl agrees with a density of states calculation by Connolly and Johnson.
Y1 - 1974
SN - 0038-1098
U6 - https://doi.org/10.1016/0038-1098(74)91165-X
VL - 15
IS - 3
SP - 655
EP - 658
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Gudat, W.
A1 - Kunz, C.
T1 - Optical constants from the far infrared to the X-ray region: Mg, Al, Cu, Ag, Au, Bi, C, and Al₂O₃
JF - Journal of the Optical Society of America (JOSA)
Y1 - 1975
SN - 0030-3941
U6 - https://doi.org/10.1364/JOSA.65.000742
VL - 65
IS - 6
SP - 742
EP - 744
PB - Optical Society of America
CY - New York
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Gudat, W.
A1 - Kunz, C.
T1 - Photoabsorption coefficient of alloys of Al with transition metals V, Fe, Ni and Cu and Pr from 30 to 150 eV photon energy
JF - Physica status solidi b
N2 - The absorption coefficient of VAI3, FeAI, NiAI, NiAl2, CuAI2, PrAl2, and of disordered V–AI (16 at% AI, 28%, 41%) and Fe–AI (11%) alloys has been measured in the region of the M₂,₃ absorption of the transition metals and the Labsorption of AI. The strong changes of the AI spectrum in the region of the 100 eV maximum upon alloying are explained as another evidence of the EXAFS (extended X-ray absorption fine structure) nature of these structures. The broad, prominent absorption peaks from the 3p excitations in V and Fe and from the 4d excitations in Pr are influenced only little on allyoing and thus appear to be of atomic origin. The fine structure at the onset of the Pr 4d transitions is identical in the metal and the alloy but differs from that of Pr oxide. The only M₂,₃ edge which is detectably shifted is that of Ni (up to 2.1 eV), whereas the onset of the AI L₂,₃ edge is shifted in all the alloys (up to 1.1 eV). The shifts are interpreted in accordance with X-ray fluorescence and nuclear resonance measurements as changes of the density of states in the valence band of the alloys.
Y1 - 1976
SN - 0031-8957
U6 - https://doi.org/10.1002/pssb.2220740211
N1 - weitere ISSN 0370-1972
VL - 74
IS - 2
SP - 507
EP - 521
PB - Wiley-VCH
CY - Berlin
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Hennings, D.
T1 - Reversible Weight change of acceptor-doped BaTiO3. Hagemann, H. J.; Hennings, D.
JF - Journal of the American Ceramic Society. 64 (1981)
Y1 - 1981
SN - 0002-7820
SP - 590
EP - 594
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Hennings, D.
A1 - Wernicke, R.
T1 - Ceramic multilayer capacitors. Hagemann, H. J.; Hennings, D.; Wernicke, R.
JF - Philips' technical review / Philips' Gloeilampenfabrieken. Philips' Gloeilampenfabrieken . 41 (1984)
Y1 - 1984
SN - 0031-7926
SP - 89
EP - 98
ER -