TY - JOUR A1 - Orzada, Stephan A1 - Fiedler, Thomas M. A1 - Bitz, Andreas A1 - Ladd, Mark E. A1 - Quick, Harald H. T1 - Local SAR compression with overestimation control to reduce maximum relative SAR overestimation and improve multi-channel RF array performance JF - Magnetic Resonance Materials in Physics, Biology and Medicine N2 - Objective In local SAR compression algorithms, the overestimation is generally not linearly dependent on actual local SAR. This can lead to large relative overestimation at low actual SAR values, unnecessarily constraining transmit array performance. Method Two strategies are proposed to reduce maximum relative overestimation for a given number of VOPs. The first strategy uses an overestimation matrix that roughly approximates actual local SAR; the second strategy uses a small set of pre-calculated VOPs as the overestimation term for the compression. Result Comparison with a previous method shows that for a given maximum relative overestimation the number of VOPs can be reduced by around 20% at the cost of a higher absolute overestimation at high actual local SAR values. Conclusion The proposed strategies outperform a previously published strategy and can improve the SAR compression where maximum relative overestimation constrains the performance of parallel transmission. Y1 - 2020 SN - 1352-8661 U6 - https://doi.org/10.1007/s10334-020-00890-0 IS - 34 (2021) SP - 153 EP - 164 PB - Springer CY - Heidelberg 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 - Schiffer, Stefan A1 - Ferrein, Alexander A1 - Lakemeyer, Gerhard T1 - Caesar: an intelligent domestic service robot JF - Intelligent service robotics N2 - In this paper we present CAESAR, an intelligent domestic service robot. In domestic settings for service robots complex tasks have to be accomplished. Those tasks benefit from deliberation, from robust action execution and from flexible methods for human–robot interaction that account for qualitative notions used in natural language as well as human fallibility. Our robot CAESAR deploys AI techniques on several levels of its system architecture. On the low-level side, system modules for localization or navigation make, for instance, use of path-planning methods, heuristic search, and Bayesian filters. For face recognition and human–machine interaction, random trees and well-known methods from natural language processing are deployed. For deliberation, we use the robot programming and plan language READYLOG, which was developed for the high-level control of agents and robots; it allows combining programming the behaviour using planning to find a course of action. READYLOG is a variant of the robot programming language Golog. We extended READYLOG to be able to cope with qualitative notions of space frequently used by humans, such as “near” and “far”. This facilitates human–robot interaction by bridging the gap between human natural language and the numerical values needed by the robot. Further, we use READYLOG to increase the flexible interpretation of human commands with decision-theoretic planning. We give an overview of the different methods deployed in CAESAR and show the applicability of a system equipped with these AI techniques in domestic service robotics Y1 - 2012 U6 - https://doi.org/10.1007/s11370-012-0118-y SN - 1861-2776 N1 - Special Issue on Artificial Intelligence Techniques for Robotics: Sensing, Representation and Action, Part I VL - 5 IS - 4 SP - 259 EP - 276 PB - Springer CY - Berlin ER - TY - JOUR A1 - Lagemaat, Miriam W. A1 - Breukels, Vincent A1 - Vos, Eline K. A1 - Kerr, Adam B. A1 - Uden, Mark J. van A1 - Orzada, Stephan A1 - Bitz, Andreas A1 - Maas, Marnix C. A1 - Scheenen, Tom W. J. T1 - ¹H MR spectroscopic imaging of the prostate at 7T using spectral-spatial pulses JF - Magnetic Resonance in Medicine N2 - Purpose To assess the feasibility of prostate ¹H MR spectroscopic imaging (MRSI) using low-power spectral-spatial (SPSP) pulses at 7T, exploiting accurate spectral selection and spatial selectivity simultaneously. Methods A double spin-echo sequence was equipped with SPSP refocusing pulses with a spectral selectivity of 1 ppm. Three-dimensional prostate ¹H-MRSI at 7T was performed with the SPSP-MRSI sequence using an 8-channel transmit array coil and an endorectal receive coil in three patients with prostate cancer and in one healthy subject. No additional water or lipid suppression pulses were used. Results Prostate ¹H-MRSI could be obtained well within specific absorption rate (SAR) limits in a clinically feasible time (10 min). Next to the common citrate signals, the prostate spectra exhibited high spermine signals concealing creatine and sometimes also choline. Residual lipid signals were observed at the edges of the prostate because of limitations in spectral and spatial selectivity. Conclusion It is possible to perform prostate ¹H-MRSI at 7T with a SPSP-MRSI sequence while using separate transmit and receive coils. This low-SAR MRSI concept provides the opportunity to increase spatial resolution of MRSI within reasonable scan times. Y1 - 2016 U6 - https://doi.org/10.1002/mrm.25569 SN - 1522-2594 VL - 75 IS - 3 SP - 933 EP - 945 PB - International Society for Magnetic Resonance in Medicine ER - TY - JOUR A1 - Ferrein, Alexander A1 - Steinbauer, Gerald A1 - Vassos, Stavros T1 - Action-Based Imperative Programming with YAGI JF - AAAI Technical Report 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, Papers from the 2012 AAAI Workshop, CogRob@AAAI 2012, Toronto, Ontario, Canada, July 22-23, 2012 SP - 24 EP - 31 PB - AAAI CY - Menlo Park ER - TY - JOUR A1 - Schaefer, Thomas A1 - Höfken, Hans-Wilhelm A1 - Schuba, Marko T1 - Windows Phone 7 from a Digital Forensics’ Perspective Y1 - 2011 N1 - ICDF2C <3, 2011, Dublin> PB - Springer CY - Berlin 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 - JOUR A1 - Maus, Stefan A1 - Höfken, Hans-Wilhelm A1 - Schuba, Marko T1 - Forensic Analysis of Geodata in Android Smartphones Y1 - 2011 N1 - Cyberforensics 2011, Glasgow SP - 1 EP - 11 ER - TY - JOUR A1 - Hagemann, Hans-Jürgen A1 - Bachmann, Peter K. A1 - Lade, H. A1 - Leers, D. A1 - Wiechert, Detlef U. A1 - Wilson, H. A1 - Fournier, D. A1 - Plamann, Karsten 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 SP - 820 EP - 826 PB - Elsevier Science CY - New York, NY [u.a.] ER - TY - JOUR A1 - Hagemann, Hans-Jürgen A1 - Bachmann, Peter 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 -