@article{OrzadaJohstMaderwaldetal.2013, author = {Orzada, Stephan and Johst, S{\"o}ren and Maderwald, Stefan and Bitz, Andreas and Solbach, Klaus and Ladd, Mark E.}, title = {Mitigation of B1(+) inhomogeneity on single-channel transmit systems with TIAMO}, series = {Magnetic Resonance in Medicine}, volume = {70}, journal = {Magnetic Resonance in Medicine}, number = {1}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.24453}, pages = {290 -- 294}, year = {2013}, language = {en} } @article{OrzadaMaderwaldPoseretal.2012, author = {Orzada, S. and Maderwald, S. and Poser, B. A. and Johst, S. and Kannengiesser, S. and Ladd, M. E. and Bitz, Andreas}, title = {Time-interleaved acquisition of modes: an analysis of SAR and image contrast implications}, series = {Magnetic Resonance in Medicine}, volume = {67}, journal = {Magnetic Resonance in Medicine}, number = {4}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2594}, doi = {10.1002/mrm.23081}, pages = {1033 -- 1041}, year = {2012}, abstract = {s the magnetic field strength and therefore the operational frequency in MRI are increased, the radiofrequency wavelength approaches the size of the human head/body, resulting in wave effects which cause signal decreases and dropouts. Especially, whole-body imaging at 7 T and higher is therefore challenging. Recently, an acquisition scheme called time-interleaved acquisition of modes has been proposed to tackle the inhomogeneity problems in high-field MRI. The basic premise is to excite two (or more) different Burn:x-wiley:07403194:media:MRM23081:tex2gif-stack-1 modes using static radiofrequency shimming in an interleaved acquisition, where the complementary radiofrequency patterns of the two modes can be exploited to improve overall signal homogeneity. In this work, the impact of time-interleaved acquisition of mode on image contrast as well as on time-averaged specific absorption rate is addressed in detail. Time-interleaved acquisition of mode is superior in Burn:x-wiley:07403194:media:MRM23081:tex2gif-stack-2 homogeneity compared with conventional radiofrequency shimming while being highly specific absorption rate efficient. Time-interleaved acquisition of modes can enable almost homogeneous high-field imaging throughout the entire field of view in PD, T2, and T2*-weighted imaging and, if a specified homogeneity criterion is met, in T1-weighted imaging as well.}, language = {en} } @article{KobusBitzUdenetal.2012, author = {Kobus, Thiele and Bitz, Andreas and Uden, Mark J. van and Lagemaat, Miram W. and Rothgang, Eva and Orzada, Stephan and Heerschap, Arend and Scheenen, Tom W. J.}, title = {In vivo 31P MR spectroscopic imaging of the human prostate at 7 T: safety and feasibility}, series = {Magnetic Resonance in Medicine}, volume = {68}, journal = {Magnetic Resonance in Medicine}, number = {6}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2594}, doi = {10.1002/mrm.24175}, pages = {1683 -- 1695}, year = {2012}, abstract = {31P MR spectroscopic imaging of the human prostate provides information about phosphorylated metabolites that could be used for prostate cancer characterization. The sensitivity of a magnetic field strength of 7 T might enable 3D 31P MR spectroscopic imaging with relevant spatial resolution in a clinically acceptable measurement time. To this end, a 31P endorectal coil was developed and combined with an eight-channel 1H body-array coil to relate metabolic information to anatomical location. An extensive safety validation was performed to evaluate the specific absorption rate, the radiofrequency field distribution, and the temperature distribution of both coils. This validation consisted of detailed Finite Integration Technique simulations, confirmed by MR thermometry and Burn:x-wiley:07403194:media:MRM24175:tex2gif-stack-1 measurements in a phantom and in vivo temperature measurements. The safety studies demonstrated that the presence of the 31P endorectal coil had no influence on the specific absorption rate levels and temperature distribution of the external eight-channel 1H array coil. To stay within a 10 g averaged local specific absorption rate of 10 W/kg, a maximum time-averaged input power of 33 W for the 1H array coil was allowed. For transmitting with the 31P endorectal coil, our safety limit of less than 1°C temperature increase in vivo during a 15-min MR spectroscopic imaging experiment was reached at a time-averaged input power of 1.9 W. With this power setting, a second in vivo measurement was performed on a healthy volunteer. Using adiabatic excitation, 3D 31P MR spectroscopic imaging produced spectra from the entire prostate in 18 min with a spatial resolution of 4 cm3. The spectral resolution enabled the separate detection of phosphocholine, phosphoethanolamine, inorganic phosphate, and other metabolites that could play an important role in the characterization of prostate cancer.}, language = {en} } @article{OrzadaMaderwaldPoseretal.2010, author = {Orzada, Stephan and Maderwald, Stefan and Poser, Benedikt Andreas and Bitz, Andreas and Quick, Harald H. and Ladd, Mark E.}, title = {RF excitation using time interleaved acquisition of modes (TIAMO) to address B1 inhomogeneity in high-field MRI}, series = {Magnetic Resonance in Medicine}, volume = {64}, journal = {Magnetic Resonance in Medicine}, number = {2}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2594}, doi = {10.1002/mrm.22527}, pages = {327 -- 333}, year = {2010}, abstract = {As the field strength and, therefore, the operational frequency in MRI is increased, the wavelength approaches the size of the human head/body, resulting in wave effects, which cause signal decreases and dropouts. Several multichannel approaches have been proposed to try to tackle these problems, including RF shimming, where each element in an array is driven by its own amplifier and modulated with a certain (constant) amplitude and phase relative to the other elements, and Transmit SENSE, where spatially tailored RF pulses are used. In this article, a relatively inexpensive and easy to use imaging scheme for 7 Tesla imaging is proposed to mitigate signal voids due to B1 field inhomogeneity. Two time-interleaved images are acquired using a different excitation mode for each. By forming virtual receive elements, both images are reconstructed together using GRAPPA to achieve a more homogeneous image, with only small SNR and SAR penalty in head and body imaging at 7 Tesla.}, language = {en} } @article{UmutluBitzMaderwaldetal.2013, author = {Umutlu, Lale and Bitz, Andreas and Maderwald, Stefan and Orzada, Stephan and Kinner, Sonja and Kraff, Oliver and Brote, Irina and Ladd, Susanne C. and Schroeder, Tobias and Forsting, Michael}, title = {Contrast-enhanced ultra-high-field liver MRI: a feasibility trial}, series = {European Journal of Radiology}, volume = {82}, journal = {European Journal of Radiology}, number = {5}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0720-048X}, doi = {10.1016/j.ejrad.2011.07.004}, pages = {760 -- 767}, year = {2013}, language = {en} } @article{YazdanbakhshSolbachBitz2012, author = {Yazdanbakhsh, Pedram and Solbach, Klaus and Bitz, Andreas}, title = {Variable power combiner for RF mode shimming in 7-T MR imaging}, series = {IEEE Transaction on Biomedical Engineering}, volume = {59}, journal = {IEEE Transaction on Biomedical Engineering}, number = {9}, publisher = {IEEE}, address = {New York}, issn = {1558-2531}, doi = {10.1109/TBME.2012.2205926}, pages = {2549 -- 2557}, year = {2012}, abstract = {This contribution discusses the utilization of RF power in an MRI system with RF mode shimming which enables the superposition of circularly polarized modes of a transmit RF coil array driven by a Butler matrix. Since the required power for the individual modes can vary widely, mode-shimming can result in a significant underutilization of the total available RF power. A variable power combiner (VPC) is proposed to improve the power utilization: it can be realized as a reconfiguration of the MRI transmit system by the inclusion of one additional matrix network which receives the power from all transmit amplifiers at its input ports and provides any desired (combined) power distribution at its output ports by controlling the phase and amplitude of the amplifiers' input signals. The power distribution at the output ports of the VPC is then fed into the "mode" ports of the coil array Butler matrix in order to superimpose the spatial modes at the highest achievable power utilization. The VPC configuration is compared to the standard configuration of the transmit chain of our MRI system with 8 transmit channels and 16 coils. In realistic scenarios, improved power utilization was achieved from 17\% to 60\% and from 14\% to 55\% for an elliptical phantom and a region of interest in the abdomen, respectively, and an increase of the power utilization of 1 dB for a region of interest in the upper leg. In general, it is found that the VPC allows significant improvement in power utilization when the shimming solution demands only a few modes to be energized, while the technique can yield loss in power utilization in cases with many modes required at high power level.}, language = {en} } @article{ProchnowGebingLadageetal.2011, author = {Prochnow, Nora and Gebing, Tina and Ladage, Kerstin and Krause-Finkeldey, Dorothee and Ourdi, Abessamad El and Bitz, Andreas and Streckert, Joachim and Hansen, Volkert and Dermietzel, Rolf}, title = {Electromagnetic field effect or simply stress? Effects of UMTS exposure on hippocampal longterm plasticity in the context of procedure related hormone release}, series = {PLoS one}, volume = {6}, journal = {PLoS one}, number = {5}, publisher = {PLOS}, address = {San Francisco}, doi = {10.1371/journal.pone.0019437}, pages = {e19437}, year = {2011}, abstract = {Harmful effects of electromagnetic fields (EMF) on cognitive and behavioural features of humans and rodents have been controversially discussed and raised persistent concern about adverse effects of EMF on general brain functions. In the present study we applied radio-frequency (RF) signals of the Universal Mobile Telecommunications System (UMTS) to full brain exposed male Wistar rats in order to elaborate putative influences on stress hormone release (corticosteron; CORT and adrenocorticotropic hormone; ACTH) and on hippocampal derived synaptic long-term plasticity (LTP) and depression (LTD) as electrophysiological hallmarks for memory storage and memory consolidation. Exposure was computer controlled providing blind conditions. Nominal brain-averaged specific absorption rates (SAR) as a measure of applied mass-related dissipated RF power were 0, 2, and 10 W/kg over a period of 120 min. Comparison of cage exposed animals revealed, regardless of EMF exposure, significantly increased CORT and ACTH levels which corresponded with generally decreased field potential slopes and amplitudes in hippocampal LTP and LTD. Animals following SAR exposure of 2 W/kg (averaged over the whole brain of 2.3 g tissue mass) did not differ from the sham-exposed group in LTP and LTD experiments. In contrast, a significant reduction in LTP and LTD was observed at the high power rate of SAR (10 W/kg). The results demonstrate that a rate of 2 W/kg displays no adverse impact on LTP and LTD, while 10 W/kg leads to significant effects on the electrophysiological parameters, which can be clearly distinguished from the stress derived background. Our findings suggest that UMTS exposure with SAR in the range of 2 W/kg is not harmful to critical markers for memory storage and memory consolidation, however, an influence of UMTS at high energy absorption rates (10 W/kg) cannot be excluded.}, 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{KraffBitzDammannetal.2010, author = {Kraff, Oliver and Bitz, Andreas and Dammann, Philipp and Ladd, Susanne C. and Ladd, Mark E. and Quick, Harald H.}, title = {An eight-channel transmit/receive multipurpose coil for musculoskeletal MR imaging at 7 T}, series = {Medical Physics}, volume = {37}, journal = {Medical Physics}, number = {12}, publisher = {Wiley}, address = {Hoboken, NJ}, issn = {2473-4209}, doi = {10.1118/1.3517176}, pages = {6368 -- 6376}, year = {2010}, abstract = {Purpose: MRI plays a leading diagnostic role in assessing the musculoskeletal (MSK) system and is well established for most questions at clinically used field strengths (up to 3 T). However, there are still limitations in imaging early stages of cartilage degeneration, very fine tendons and ligaments, or in locating nerve lesions, for example. 7 T MRI of the knee has already received increasing attention in the current published literature, but there is a strong need to develop new radiofrequency (RF) coils to assess more regions of the MSK system. In this work, an eight-channel transmit/receive RF array was built as a multipurpose coil for imaging some of the thus far neglected regions. An extensive coil characterization protocol and first in vivo results of the human wrist, shoulder, elbow, knee, and ankle imaged at 7 T will be presented. Methods: Eight surface loop coils with a dimension ofurn:x-wiley:00942405:media:mp7176:mp7176-math-0001 were machined from FR4 circuit board material. To facilitate easy positioning, two coil clusters, each with four loop elements, were combined to one RF transmit/receive array. An overlapped and shifted arrangement of the coil elements was chosen to reduce the mutual inductance between neighboring coils. A phantom made of body-simulating liquid was used for tuning and matching on the bench. Afterward, the S-parameters were verified on a human wrist, elbow, and shoulder. For safety validation, a detailed compliance test was performed including full wave simulations of the RF field distribution and the corresponding specific absorption rate (SAR) for all joints. In vivo images of four volunteers were assessed with gradient echo and spin echo sequences modified to obtain optimal image contrast, full anatomic coverage, and the highest spatial resolution within a reasonable acquisition time. The performance of the RF coil was additionally evaluated by in vivo B1 mapping. Results: A comparison of B1 per unit power, flip angle distribution, and anatomic images showed a fairly homogeneous excitation for the smaller joints (elbow, wrist, and ankle), while for the larger joints, the shoulder and especially the knee, B1 inhomogeneities and limited penetration depth were more pronounced. However, the greater part of the shoulder joint could be imaged.In vivo images rendered very fine anatomic details such as fascicles of the median nerve and the branching of the nerve bundles. High-resolution images of cartilage, labrum, and tendons could be acquired. Additionally, turbo spin echo (TSE) and inversion recovery sequences performed very well. Conclusions: This study demonstrates that the concept of two four-channel transmit/receive RF arrays can be used as a multipurpose coil for high-resolutionin vivo MR imaging of the musculoskeletal system at 7 T. Not only gradient echo but also typical clinical and SAR-intensive sequences such as STIR and TSE performed well. Imaging of small structures and peripheral nerves could in particular benefit from this technique.}, language = {en} } @article{OrzadaLaddBitz2016, author = {Orzada, Stephan and Ladd, Mark E. and Bitz, Andreas}, title = {A method to approximate maximum local SAR in multichannel transmit MR systems without transmit phase information}, series = {Magnetic Resonance in Medicine}, volume = {78}, journal = {Magnetic Resonance in Medicine}, number = {2}, publisher = {International Society for Magnetic Resonance in Medicine}, issn = {1522-2594}, doi = {10.1002/mrm.26398}, pages = {805 -- 811}, year = {2016}, abstract = {Purpose To calculate local specific absorption rate (SAR) correctly, both the amplitude and phase of the signal in each transmit channel have to be known. In this work, we propose a method to derive a conservative upper bound for the local SAR, with a reasonable safety margin without knowledge of the transmit phases of the channels. Methods The proposed method uses virtual observation points (VOPs). Correction factors are calculated for each set of VOPs that prevent underestimation of local SAR when the VOPs are applied with the correct amplitudes but fixed phases. Results The proposed method proved to be superior to the worst-case calculation based on the maximum eigenvalue of the VOPs. The mean overestimation for six coil setups could be reduced, whereas no underestimation of the maximum local SAR occurred. In the best investigated case, the overestimation could be reduced from a factor of 3.3 to a factor of 1.7. Conclusion The upper bound for the local SAR calculated with the proposed method allows a fast estimation of the local SAR based on power measurements in the transmit channels and facilitates SAR monitoring in systems that do not have the capability to monitor transmit phases}, language = {en} } @article{ChenSchoembergKraffetal.2016, author = {Chen, Bixia and Schoemberg, Tobias and Kraff, Oliver and Dammann, Philipp and Bitz, Andreas and Schlamann, Marc and Quick, Harald H. and Ladd, Mark E. and Sure, Ulrich and Wrede, Karsten H.}, title = {Cranial fixation plates in cerebral magnetic resonance imaging: a 3 and 7 Tesla in vivo image quality study}, series = {Magnetic Resonance Materials in Physics, Biology and Medicine}, volume = {29}, journal = {Magnetic Resonance Materials in Physics, Biology and Medicine}, number = {3}, publisher = {Springer}, address = {Berlin}, issn = {1352-8661}, doi = {10.1007/s10334-016-0548-1}, pages = {389 -- 398}, year = {2016}, abstract = {Objective This study assesses and quantifies impairment of postoperative magnetic resonance imaging (MRI) at 7 Tesla (T) after implantation of titanium cranial fixation plates (CFPs) for neurosurgical bone flap fixation. Materials and methods The study group comprised five patients who were intra-individually examined with 3 and 7 T MRI preoperatively and postoperatively (within 72 h/3 months) after implantation of CFPs. Acquired sequences included T₁-weighted magnetization-prepared rapid-acquisition gradient-echo (MPRAGE), T₂-weighted turbo-spin-echo (TSE) imaging, and susceptibility-weighted imaging (SWI). Two experienced neurosurgeons and a neuroradiologist rated image quality and the presence of artifacts in consensus reading. Results Minor artifacts occurred around the CFPs in MPRAGE and T2 TSE at both field strengths, with no significant differences between 3 and 7 T. In SWI, artifacts were accentuated in the early postoperative scans at both field strengths due to intracranial air and hemorrhagic remnants. After resorption, the brain tissue directly adjacent to skull bone could still be assessed. Image quality after 3 months was equal to the preoperative examinations at 3 and 7 T. Conclusion Image quality after CFP implantation was not significantly impaired in 7 T MRI, and artifacts were comparable to those in 3 T MRI.}, language = {en} } @article{SchmidtForkmannSinkeetal.2016, author = {Schmidt, K. and Forkmann, K. and Sinke, C. and Gratz, M. and Bitz, Andreas and Bingel, U.}, title = {The differential effect of trigeminal vs. peripheral pain stimulation on visual processing and memory encoding is influenced by pain-related fear}, series = {NeuroImage}, volume = {134}, journal = {NeuroImage}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1053-8119}, doi = {10.1016/j.neuroimage.2016.03.026}, pages = {386 -- 395}, year = {2016}, abstract = {Compared to peripheral pain, trigeminal pain elicits higher levels of fear, which is assumed to enhance the interruptive effects of pain on concomitant cognitive processes. In this fMRI study we examined the behavioral and neural effects of trigeminal (forehead) and peripheral (hand) pain on visual processing and memory encoding. Cerebral activity was measured in 23 healthy subjects performing a visual categorization task that was immediately followed by a surprise recognition task. During the categorization task subjects received concomitant noxious electrical stimulation on the forehead or hand. Our data show that fear ratings were significantly higher for trigeminal pain. Categorization and recognition performance did not differ between pictures that were presented with trigeminal and peripheral pain. However, object categorization in the presence of trigeminal pain was associated with stronger activity in task-relevant visual areas (lateral occipital complex, LOC), memory encoding areas (hippocampus and parahippocampus) and areas implicated in emotional processing (amygdala) compared to peripheral pain. Further, individual differences in neural activation between the trigeminal and the peripheral condition were positively related to differences in fear ratings between both conditions. Functional connectivity between amygdala and LOC was increased during trigeminal compared to peripheral painful stimulation. Fear-driven compensatory resource activation seems to be enhanced for trigeminal stimuli, presumably due to their exceptional biological relevance.}, language = {en} } @article{BankOrzadaSmitsetal.2015, author = {Bank, Bart L. van de and Orzada, Stephan and Smits, Frits and Lagemaat, Miriam W. and Rodgers, Christopher T. and Bitz, Andreas and Scheenen, Tom W. J.}, title = {Optimized (31) P MRS in the human brain at 7 T with a dedicated RF coil setup}, series = {NMR in Biomedicine}, volume = {28}, journal = {NMR in Biomedicine}, number = {11}, publisher = {Wiley}, address = {Weinheim}, issn = {1099-1492}, doi = {10.1002/nbm.3422}, pages = {1570 -- 1578}, year = {2015}, language = {en} } @article{NoureddineBitzLaddetal.2015, author = {Noureddine, Yacine and Bitz, Andreas and Ladd, Mark E. and Th{\"u}rling, Markus and Ladd, Susanne C. and Schaefers, Gregor and Kraff, Oliver}, title = {Experience with magnetic resonance imaging of human subjects with passive implants and tattoos at 7 T: a retrospective study}, series = {Magnetic Resonance Materials in Physics, Biology and Medicine}, volume = {28}, journal = {Magnetic Resonance Materials in Physics, Biology and Medicine}, number = {6}, publisher = {Springer}, address = {Berlin}, issn = {1352-8661}, doi = {10.1007/s10334-015-0499-y}, pages = {577 -- 590}, year = {2015}, language = {en} } @article{LagemaatBreukelsVosetal.2016, author = {Lagemaat, Miriam W. and Breukels, Vincent and Vos, Eline K. and B., Adam and Uden, Mark J. van and Orzada, Stephan and Bitz, Andreas and Maas, Marnix C. and Scheenen, Tom W. J.}, title = {¹H MR spectroscopic imaging of the prostate at 7T using spectral-spatial pulses}, series = {Magnetic Resonance in Medicine}, volume = {75}, journal = {Magnetic Resonance in Medicine}, number = {3}, publisher = {International Society for Magnetic Resonance in Medicine}, issn = {1522-2594}, doi = {10.1002/mrm.25569}, pages = {933 -- 945}, year = {2016}, abstract = {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.}, language = {en} } @article{VosLagemaatBarentszetal.2014, author = {Vos, E. K. and Lagemaat, M. W. and Barentsz, J. O. and F{\"u}tterer, J. J. and Zamecnik, P. and Roozen, H. and Orzada, S. and Bitz, Andreas and Maas, M. C. and Scheenen, T. W. J.}, title = {Image quality and cancer visibility of T2-weighted Magnetic Resonance Imaging of the prostate at 7 Tesla}, series = {European Radiology}, volume = {24}, journal = {European Radiology}, number = {8}, publisher = {Springer}, address = {Cham}, issn = {1432-1084}, doi = {10.1007/s00330-014-3234-6}, pages = {1950 -- 1958}, year = {2014}, abstract = {Objectives To assess the image quality of T2-weighted (T2w) magnetic resonance imaging of the prostate and the visibility of prostate cancer at 7 Tesla (T). Materials \& methods Seventeen prostate cancer patients underwent T2w imaging at 7T with only an external transmit/receive array coil. Three radiologists independently scored images for image quality, visibility of anatomical structures, and presence of artefacts. Krippendorff's alpha and weighted kappa statistics were used to assess inter-observer agreement. Visibility of prostate cancer lesions was assessed by directly linking the T2w images to the confirmed location of prostate cancer on histopathology. Results T2w imaging at 7T was achievable with 'satisfactory' (3/5) to 'good' (4/5) quality. Visibility of anatomical structures was predominantly scored as 'satisfactory' (3/5) and 'good' (4/5). If artefacts were present, they were mostly motion artefacts and, to a lesser extent, aliasing artefacts and noise. Krippendorff's analysis revealed an α = 0.44 between three readers for the overall image quality scores. Clinically significant cancer lesions in both peripheral zone and transition zone were visible at 7T. Conclusion T2w imaging with satisfactory to good quality can be routinely acquired, and cancer lesions were visible in patients with prostate cancer at 7T using only an external transmit/receive body array coil.}, language = {en} } @article{LagemaatMaasVosetal.2015, author = {Lagemaat, Miriam W. and Maas, Marnix C. and Vos, Eline K. and Bitz, Andreas and Orzada, Stephan and Weiland, Elisabeth and Uden, Mark J. van and Kobus, Thiele and Heerschap, Arend and Scheenen, Tom W. J.}, title = {(31) P MR spectroscopic imaging of the human prostate at 7 T: T1 relaxation times, Nuclear Overhauser Effect, and spectral characterization}, series = {Magnetic Resonance in Medicine}, volume = {73}, journal = {Magnetic Resonance in Medicine}, number = {3}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.25209}, pages = {909 -- 920}, year = {2015}, language = {en} } @article{TheysohnKraffEilersetal.2014, author = {Theysohn, Jens M. and Kraff, Oliver and Eilers, Kristina and Andrade, Dorian and Gerwig, Marcus and Timmann, Dagmar and Schmitt, Franz and Ladd, Mark E. and Ladd, Susanne C. and Bitz, Andreas}, title = {Vestibular effects of a 7 Tesla MRI examination compared to 1.5 T and 0 T in healthy volunteers}, series = {PLoS one}, volume = {9}, journal = {PLoS one}, number = {3}, publisher = {PLOS}, address = {San Francisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0092104}, pages = {e92104}, year = {2014}, abstract = {Ultra-high-field MRI (7 Tesla (T) and above) elicits more temporary side-effects compared to 1.5 T and 3 T, e.g. dizziness or "postural instability" even after exiting the scanner. The current study aims to assess quantitatively vestibular performance before and after exposure to different MRI scenarios at 7 T, 1.5 T and 0 T. Sway path and body axis rotation (Unterberger's stepping test) were quantitatively recorded in a total of 46 volunteers before, 2 minutes after, and 15 minutes after different exposure scenarios: 7 T head MRI (n = 27), 7 T no RF (n = 22), 7 T only B₀ (n = 20), 7 T in \& out B₀ (n = 20), 1.5 T no RF (n = 20), 0 T (n = 15). All exposure scenarios lasted 30 minutes except for brief one minute exposure in 7 T in \& out B₀. Both measures were documented utilizing a 3D ultrasound system. During sway path evaluation, the experiment was repeated with eyes both open and closed. Sway paths for all long-lasting 7 T scenarios (normal, no RF, only B₀) with eyes closed were significantly prolonged 2 minutes after exiting the scanner, normalizing after 15 minutes. Brief exposure to 7 T B₀ or 30 minutes exposure to 1.5 T or 0 T did not show significant changes. End positions after Unterberger's stepping test were significantly changed counter-clockwise after all 7 T scenarios, including the brief in \& out B₀ exposure. Shorter exposure resulted in a smaller alteration angle. In contrast to sway path, reversal of changes in body axis rotation was incomplete after 15 minutes. 1.5 T caused no rotational changes. The results show that exposure to the 7 Tesla static magnetic field causes only a temporary dysfunction or "over-compensation" of the vestibular system not measurable at 1.5 or 0 Tesla. Radiofrequency fields, gradient switching, and orthostatic dysregulation do not seem to play a role.}, 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} } @article{SchlamannVoigtMaderwaldetal.2010, author = {Schlamann, Marc and Voigt, Melanie A. and Maderwald, Stefan and Bitz, Andreas and Kraff, Oliver and Ladd, Susanne C. and Ladd, Mark E. and Forsting, Michael and Wilhelm, Hans}, title = {Exposure to high-field MRI does not affect cognitive function}, series = {Journal of Magnetic Resonance Imaging}, volume = {31}, journal = {Journal of Magnetic Resonance Imaging}, number = {5}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2586}, doi = {10.1002/jmri.22065}, pages = {1061 -- 1066}, year = {2010}, abstract = {Purpose To assess potential cognitive deficits under the influence of static magnetic fields at various field strengths some studies already exist. These studies were not focused on attention as the most vulnerable cognitive function. Additionally, mostly no magnetic resonance imaging (MRI) sequences were performed. Materials and Methods In all, 25 right-handed men were enrolled in this study. All subjects underwent one MRI examination of 63 minutes at 1.5 T and one at 7 T within an interval of 10 to 30 days. The order of the examinations was randomized. Subjects were referred to six standardized neuropsychological tests strictly focused on attention immediately before and after each MRI examination. Differences in neuropsychological variables between the timepoints before and after each MRI examination were assessed and P-values were calculated Results Only six subtests revealed significant differences between pre- and post-MRI. In these tests the subjects achieved better results in post-MRI testing than in pre-MRI testing (P = 0.013-0.032). The other tests revealed no significant results. Conclusion The improvement in post-MRI testing is only explicable as a result of learning effects. MRI examinations, even in ultrahigh-field scanners, do not seem to have any persisting influence on the attention networks of human cognition immediately after exposure.}, language = {en} } @article{BitzZhouElQuardietal.2009, author = {Bitz, Andreas and Zhou, Yi and El Quardi, Abdessamad and Streckert, Joachim}, title = {Occupational Exposure at Mobile Communication Base Station Antenna Sites}, series = {Frequenz}, volume = {63}, journal = {Frequenz}, number = {7-8}, issn = {2191-6349}, doi = {10.1515/FREQ.2009.63.7-8.123}, pages = {123 -- 128}, year = {2009}, language = {en} } @article{SchlamannYoonMaderwaldetal.2010, author = {Schlamann, Marc and Yoon, Min-Suk and Maderwald, Stefan and Pietrzyk, Thomas and Bitz, Andreas and Gerwig, Marcus and Forsting, Michael and Ladd, Susanne C. and Ladd, Mark E. and Kastrup, Oliver}, title = {Short term effects of magnetic resonance imaging on excitability of the motor cortex at 1.5T and 7T}, series = {Academic Radiology}, volume = {17}, journal = {Academic Radiology}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1076-6332}, doi = {10.1016/j.acra.2009.10.004}, pages = {277 -- 281}, year = {2010}, abstract = {Rationale and Objectives The increasing spread of high-field and ultra-high-field magnetic resonance imaging (MRI) scanners has encouraged new discussion of the safety aspects of MRI. Few studies have been published on possible cognitive effects of MRI examinations. The aim of this study was to examine whether changes are measurable after MRI examinations at 1.5 and 7 T by means of transcranial magnetic stimulation (TMS). Materials and Methods TMS was performed in 12 healthy, right-handed male volunteers. First the individual motor threshold was specified, and then the cortical silent period (SP) was measured. Subsequently, the volunteers were exposed to the 1.5-T MRI scanner for 63 minutes using standard sequences. The MRI examination was immediately followed by another TMS session. Fifteen minutes later, TMS was repeated. Four weeks later, the complete setting was repeated using a 7-T scanner. Control conditions included lying in the 1.5-T scanner for 63 minutes without scanning and lying in a separate room for 63 minutes. TMS was performed in the same way in each case. For statistical analysis, Wilcoxon's rank test was performed. Results Immediately after MRI exposure, the SP was highly significantly prolonged in all 12 subjects at 1.5 and 7 T. The motor threshold was significantly increased. Fifteen minutes after the examination, the measured value tended toward normal again. Control conditions revealed no significant differences. Conclusion MRI examinations lead to a transient and highly significant alteration in cortical excitability. This effect does not seem to depend on the strength of the static magnetic field.}, language = {en} } @article{KraffBitzKruszonaetal.2009, author = {Kraff, Oliver and Bitz, Andreas and Kruszona, Stefan and Orzada, Stephan and Schaefer, Lena C. and Theysohn, Jens M. and Maderwald, Stefan and Ladd, Mark E. and Quick, Harald H.}, title = {An eight-channel phased array RF coil for spine MR imaging at 7 T}, series = {Investigative Radiology}, volume = {44}, journal = {Investigative Radiology}, number = {11}, publisher = {Lippincott Williams \& Wilkins}, issn = {1536-0210}, doi = {10.1097/RLI.0b013e3181b24ab7}, pages = {734 -- 740}, year = {2009}, language = {en} } @article{SchlamannYoonMaderwaldetal.2009, author = {Schlamann, M. and Yoon, M.-S. and Maderwald, S. and Pietrzyk, T. and Bitz, Andreas and Gerwig, M. and Forsting, M. and Ladd, S. C. and Ladd, M. E. and Kastrup, O.}, title = {Auswirkungen der Magnetresonanztomografie auf die Elektrophysiologie des motorischen Kortex: eine Studie mit transkranieller Magnetstimulation}, series = {R{\"o}Fo - Fortschritte auf dem Giebiet der R{\"o}ntgenstrahlen und der bildgebenden Verfahren}, volume = {181}, journal = {R{\"o}Fo - Fortschritte auf dem Giebiet der R{\"o}ntgenstrahlen und der bildgebenden Verfahren}, number = {3}, publisher = {Thieme}, address = {Stuttgart}, issn = {1438-9029}, doi = {10.1055/s-0028-1109038}, pages = {215 -- 219}, year = {2009}, language = {de} } @article{KlompBitzHeerschapetal.2009, author = {Klomp, D. W. J. and Bitz, Andreas and Heerschap, A. and Scheenen, T. W. J.}, title = {Proton spectroscopic imaging of the human prostate at 7 T}, series = {NMR in Biomedicine}, volume = {22}, journal = {NMR in Biomedicine}, number = {5}, issn = {1099-1492}, doi = {10.1002/nbm.1360}, pages = {495 -- 501}, year = {2009}, language = {en} } @article{LerchlKruegerNiehausetal.2008, author = {Lerchl, Alexander and Kr{\"u}ger, Heike and Niehaus, Michael and Streckert, Joachim R. and Bitz, Andreas and Hansen, Volkert}, title = {Effects of mobile phone electromagnetic fields at nonthermal SAR values on melatonin and body weight of Djungarian hamsters (Phodopus sungorus)}, series = {Journal of Pineal Research}, volume = {44}, journal = {Journal of Pineal Research}, number = {3}, issn = {1600-079X}, doi = {10.1111/j.1600-079X.2007.00522.x}, pages = {267 -- 272}, year = {2008}, language = {en} } @article{FiedlerLaddBitz2017, author = {Fiedler, Thomas M. and Ladd, Mark E. and Bitz, Andreas}, title = {SAR Simulations \& Safety}, series = {NeuroImage}, journal = {NeuroImage}, number = {Epub ahead of print}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1053-8119}, doi = {10.1016/j.neuroimage.2017.03.035}, year = {2017}, language = {en} } @article{NoureddineKraffLaddetal.2017, author = {Noureddine, Yacine and Kraff, Oliver and Ladd, Mark E. and Wrede, Karsten H. and Chen, Bixia and Quick, Harald H. and Schaefers, Gregor and Bitz, Andreas}, title = {In vitro and in silico assessment of RF-induced heating around intracranial aneurysm clips at 7 Tesla}, series = {Magnetic Resonance in Medicine}, journal = {Magnetic Resonance in Medicine}, number = {Early view}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.26650}, pages = {14 Seiten}, year = {2017}, language = {en} } @article{FiedlerLaddBitz2017, author = {Fiedler, Thomas M. and Ladd, Mark E. and Bitz, Andreas}, title = {RF safety assessment of a bilateral four-channel transmit/receive 7 Tesla breast coil: SAR versus temperature limits}, series = {Medical Physics}, volume = {44}, journal = {Medical Physics}, number = {1}, doi = {10.1002/mp.12034}, pages = {143 -- 157}, year = {2017}, language = {en} } @article{LagemaatVosMaasetal.2014, author = {Lagemaat, Miriam W. and Vos, Eline K. and Maas, Marnix C. and Bitz, Andreas and Orzada, Stephan and Uden, Mark J. van and Kobus, Thiele and Heerschap, Arend and Scheenen, Tom W. J.}, title = {Phosphorus magnetic resonance spectroscopic imaging at 7 T in patients with prostate cancer}, series = {Investigative Radiology}, volume = {49}, journal = {Investigative Radiology}, number = {5}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia, Pa.}, issn = {1536-0210}, doi = {10.1097/RLI.0000000000000012}, pages = {363 -- 372}, year = {2014}, abstract = {Objectives The aim of this study was to identify characteristics of phosphorus (³¹P) spectra of the human prostate and to investigate changes of individual phospholipid metabolites in prostate cancer through in vivo ³¹P magnetic resonance spectroscopic imaging (MRSI) at 7 T. Materials and Methods In this institutional review board-approved study, 15 patients with biopsy-proven prostate cancer underwent T₂-weighted magnetic resonance imaging and 3-dimensional ³¹P MRSI at 7 T. Voxels were selected at the tumor location, in normal-appearing peripheral zone tissue, normal-appearing transition zone tissue, and in the base of the prostate close to the seminal vesicles. Phosphorus metabolite ratios were determined and compared between tissue types. Results Signals of phosphoethanolamine (PE) and phosphocholine (PC) were present and well resolved in most ³¹P spectra in the prostate. Glycerophosphocholine signals were observable in 43\% of the voxels in malignant tissue, but in only 10\% of the voxels in normal-appearing tissue away from the seminal vesicles. In many spectra, independent of tissue type, 2 peaks resonated in the chemical shift range of inorganic phosphate, possibly representing 2 separate pH compartments. The PC/PE ratio in the seminal vesicles was highly elevated compared with the prostate in 5 patients. A considerable overlap of ³¹P metabolite ratios was found between prostate cancer and normal-appearing prostate tissue, preventing direct discrimination of these tissues. The only 2 patients with high Gleason scores tumors (≥4+5) presented with high PC and glycerophosphocholine levels in their cancer lesions. Conclusions Phosphorus MRSI at 7 T shows distinct features of phospholipid metabolites in the prostate gland and its surrounding structures. In this exploratory study, no differences in ³¹P metabolite ratios were observed between prostate cancer and normal-appearing prostate tissue possibly because of the partial volume effects of small tumor foci in large MRSI voxels.}, language = {en} } @article{MaasVosLagemaatetal.2014, author = {Maas, Marnix C. and Vos, Eline K. and Lagemaat, Miriam W. and Bitz, Andreas and Orzada, Stephan and Kobus, Thiele and Kraff, Oliver and Maderwald, Stefan and Ladd, Mark E. and Scheenen, Tom W. J.}, title = {Feasibility of T₂-weighted turbo spin echo imaging of the human prostate at 7 tesla}, series = {Magnetic Resonance in Medicine}, volume = {71}, journal = {Magnetic Resonance in Medicine}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.24818}, pages = {1711 -- 1719}, year = {2014}, abstract = {Purpose To demonstrate that high quality T₂-weighted (T2w) turbo spin-echo (TSE) imaging of the complete prostate can be achieved routinely and within safety limits at 7 T, using an external transceive body array coil only. Methods Nine healthy volunteers and 12 prostate cancer patients were scanned on a 7 T whole-body system. Preparation consisted of B₀ and radiofrequency shimming and localized flip angle calibration. T₁ and T₂ relaxation times were measured and used to define the T2w-TSE protocol. T2w imaging was performed using a TSE sequence (pulse repetition time/echo time 3000-3640/71 ms) with prolonged excitation and refocusing pulses to reduce specific absorption rate. Results High quality T2w TSE imaging was performed in less than 2 min in all subjects. Tumors of patients with gold-standard tumor localization (MR-guided biopsy or prostatectomy) were well visualized on 7 T imaging (n = 3). The number of consecutive slices achievable within a 10-g averaged specific absorption rate limit of 10 W/kg was ≥28 in all subjects, sufficient for full prostate coverage with 3-mm slices in at least one direction. Conclusion High quality T2w TSE prostate imaging can be performed routinely and within specific absorption rate limits at 7 T with an external transceive body array.}, language = {en} } @article{UmutluKraffFischeretal.2013, author = {Umutlu, Lale and Kraff, Oliver and Fischer, Anja and Kinner, Sonja and Maderwald, Stefan and Nassenstein, Kai and Nensa, Felix and Gr{\"u}neisen, Johannes and Orzada, Stephan and Bitz, Andreas and Forsting, Michael and Ladd, Mark E. and Lauenstein, Thomas C.}, title = {Seven-Tesla MRI of the female pelvis}, series = {European Radiology}, volume = {23}, journal = {European Radiology}, number = {9}, publisher = {Springer}, address = {Berlin}, issn = {1432-1084}, doi = {10.1007/s00330-013-2868-0}, pages = {2364 -- 2373}, year = {2013}, language = {en} } @article{BitzFelderWittig2013, author = {Bitz, Andreas and Felder, Jorg and Wittig, Tilmann}, title = {Designing MRI Coils with Aid of Simulation}, series = {Microwaves \& RF}, volume = {52}, journal = {Microwaves \& RF}, number = {7}, publisher = {Penton}, address = {Cleveland, Ohio}, issn = {0745-2993}, pages = {56}, year = {2013}, language = {en} } @article{KraffWredeSchoembergetal.2013, author = {Kraff, Oliver and Wrede, Karsten H. and Schoemberg, Tobias and Dammann, Philipp and Noureddine, Yacine and Orzada, Stephan and Ladd, Mark E. and Bitz, Andreas}, title = {MR safety assessment of potential RF heating from cranial fixation plates at 7 T}, series = {Medical Physics}, volume = {40}, journal = {Medical Physics}, number = {4}, publisher = {Wiley}, address = {Hoboken}, issn = {2473-4209}, doi = {10.1118/1.4795347}, pages = {042302-1 -- 042302-10}, year = {2013}, language = {en} } @article{UmutluMaderwaldKinneretal.2013, author = {Umutlu, L. and Maderwald, S. and Kinner, S. and Kraff, O. and Bitz, Andreas and Orzada, S. and Johst, S. and Wrede, K. and Forsting, M. and Ladd, M. E. and Lauenstein, T. C. and Quick, H. H.}, title = {First-pass contrast-enhanced renal MRA at 7 Tesla: initial results}, series = {European Radiology}, volume = {23}, journal = {European Radiology}, number = {4}, publisher = {Springer}, address = {Berlin}, issn = {1432-1084}, doi = {10.1007/s00330-012-2666-0}, pages = {1059 -- 1066}, year = {2013}, 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{HueningHeuermannWacheetal.2018, author = {H{\"u}ning, Felix and Heuermann, Holger and Wache, Franz-Josef and Jajo, Rami Audisho}, title = {A new wireless sensor interface using dual-mode radio}, series = {Journal of Sensors and Sensor Systems : JSSS}, volume = {Volume 7}, journal = {Journal of Sensors and Sensor Systems : JSSS}, number = {2}, publisher = {Copernicus Publ.}, address = {G{\"o}ttingen}, doi = {10.5194/jsss-7-507-2018}, pages = {507 -- 515}, year = {2018}, abstract = {The integration of sensors is one of the major tasks in embedded, control and "internet of things" (IoT) applications. For the integration mainly digital interfaces are used, starting from rather simple pulse-width modulation (PWM) interface to more complex interfaces like CAN (Controller Area Network). Even though these interfaces are tethered by definition, a wireless realization is highly welcome in many applications to reduce cable and connector cost, increase the flexibility and realize new emerging applications like wireless control systems. Currently used wireless solutions like Bluetooth, WirelessHART or IO-Link Wireless use dedicated communication standards and corresponding higher protocol layers to realize the wireless communication. Due to the complexity of the communication and the protocol handling, additional latency and jitter are introduced to the data communication that can meet the requirements for many applications. Even though tunnelling of other bus data like CAN data is generally also possible the latency and jitter prevent the tunnelling from being transparent for the bus system. Therefore a new basic technology based on dual-mode radio is used to realize a wireless communication on the physical layer only, enabling a reliable and real-time data transfer. As this system operates on the physical layer it is independent of any higher layers of the OSI (open systems interconnection) model. Hence it can be used for several different communication systems to replace the tethered physical layer. A prototype is developed and tested for real-time wireless PWM, SENT (single-edge nibble transmission) and CAN data transfer with very low latency and jitter.}, language = {en} } @inproceedings{AlhwarinFerreinScholl2018, author = {Alhwarin, Faraj and Ferrein, Alexander and Scholl, Ingrid}, title = {CRVM: Circular Random Variable-based Matcher - A Novel Hashing Method for Fast NN Search in High-dimensional Spaces}, series = {Proceedings of the 7th International Conference on Pattern Recognition Applications and Methods, ICPRAM 2018}, booktitle = {Proceedings of the 7th International Conference on Pattern Recognition Applications and Methods, ICPRAM 2018}, isbn = {978-989-758-276-9}, doi = {10.5220/0006692802140221}, pages = {214 -- 221}, year = {2018}, language = {en} } @inproceedings{AlhwarinSchifferFerreinetal.2018, author = {Alhwarin, Faraj and Schiffer, Stefan and Ferrein, Alexander and Scholl, Ingrid}, title = {Optimized KinectFusion Algorithm for 3D Scanning Applications}, series = {Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies - Volume 2: BIOIMAGING}, booktitle = {Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies - Volume 2: BIOIMAGING}, isbn = {978-989-758-278-3}, doi = {10.5220/0006594700500057}, pages = {50 -- 57}, year = {2018}, language = {en} } @inproceedings{HofmannMatareSchifferetal.2018, author = {Hofmann, Till and Matar{\´e}, Victor and Schiffer, Stefan and Ferrein, Alexander and Lakemeyer, Gerhard}, title = {Constraint-based online transformation of abstract plans into executable robot actions}, series = {Proceedings of the 2018 AAAI Spring Symposium on Integrating Representation, Reasoning, Learning, and Execution for Goal Directed Autonomy}, booktitle = {Proceedings of the 2018 AAAI Spring Symposium on Integrating Representation, Reasoning, Learning, and Execution for Goal Directed Autonomy}, pages = {549 -- 553}, year = {2018}, language = {en} } @inproceedings{FerreinSchifferKallweit2018, author = {Ferrein, Alexander and Schiffer, Stefan and Kallweit, Stephan}, title = {The ROSIN Education Concept - Fostering ROS Industrial-Related Robotics Education in Europe}, series = {ROBOT 2017: Third Iberian Robotics Conference}, booktitle = {ROBOT 2017: Third Iberian Robotics Conference}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-70836-2}, doi = {10.1007/978-3-319-70836-2_31}, pages = {370 -- 381}, year = {2018}, language = {en} } @inproceedings{HofmannMatareNeumannetal.2018, author = {Hofmann, Till and Matar{\´e}, Victor and Neumann, Tobias and Sch{\"o}nitz, Sebastian and Henke, Christoph and Limpert, Nicolas and Niemueller, Tim and Ferrein, Alexander and Jeschke, Sabina and Lakemeyer, Gerhard}, title = {Enhancing Software and Hardware Reliability for a Successful Participation in the RoboCup Logistics League 2017}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-00308-1}, doi = {10.1007/978-3-030-00308-1_40}, pages = {486 -- 497}, year = {2018}, language = {en} } @article{SchifferFerrein2018, author = {Schiffer, Stefan and Ferrein, Alexander}, title = {ERIKA—Early Robotics Introduction at Kindergarten Age}, series = {Multimodal Technologies Interact}, volume = {2}, journal = {Multimodal Technologies Interact}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {2414-4088}, doi = {10.3390/mti2040064}, pages = {15}, year = {2018}, abstract = {In this work, we report on our attempt to design and implement an early introduction to basic robotics principles for children at kindergarten age. One of the main challenges of this effort is to explain complex robotics contents in a way that pre-school children could follow the basic principles and ideas using examples from their world of experience. What sets apart our effort from other work is that part of the lecturing is actually done by a robot itself and that a quiz at the end of the lesson is done using robots as well. The humanoid robot Pepper from Softbank, which is a great platform for human-robot interaction experiments, was used to present a lecture on robotics by reading out the contents to the children making use of its speech synthesis capability. A quiz in a Runaround-game-show style after the lecture activated the children to recap the contents they acquired about how mobile robots work in principle. In this quiz, two LEGO Mindstorm EV3 robots were used to implement a strongly interactive scenario. Besides the thrill of being exposed to a mobile robot that would also react to the children, they were very excited and at the same time very concentrated. We got very positive feedback from the children as well as from their educators. To the best of our knowledge, this is one of only few attempts to use a robot like Pepper not as a tele-teaching tool, but as the teacher itself in order to engage pre-school children with complex robotics contents.}, language = {en} } @article{HueningHeuermannWache2018, author = {H{\"u}ning, Felix and Heuermann, Holger and Wache, Franz-Josef}, title = {Wireless CAN}, series = {Etz: Elektrotechnik \& Automation}, volume = {139}, journal = {Etz: Elektrotechnik \& Automation}, number = {10}, publisher = {VDE-Verlag}, address = {Wuppertal}, issn = {0170-1711}, pages = {22 -- 26}, year = {2018}, abstract = {In modernen elektronischen und mechatronischen Systemen, z. B. im industriellen oder automobil Bereich, kommunizieren eingebettete Steuerger{\"a}te und Sensoren vielfach {\"u}ber Bussysteme wie CAN oder LIN. Die Kommunikation findet in der Regel drahtgebunden statt, so dass der Kabelbaum f{\"u}r die Kommunikation sehr groß werden kann. Daher ist es naheliegend, Leitungen und dazugeh{\"o}rige Stecker, z. B. f{\"u}r nicht-sicherheitskritische Komfortsysteme, einzusparen und diese durch gerichtete Funkstrecken f{\"u}r kurze Entfernungen zu ersetzen. Somit k{\"o}nnten Komponenten wie ECUs oder Sensoren kabel- und steckerlos in ein Bussystem integriert werden. Zudem ist eine einfache galvanische und mechanische Trennung zu erreichen. Funk{\"u}bertragung wird bei diesen Bussystemen derzeit nicht eingesetzt, da insbesondere die Echtzeitf{\"a}higkeit und die Robustheit der vorhandenen Funksysteme nicht den Anforderungen der Anwendungen entspricht. Zudem sind bestehende Funksysteme wie WLAN oder Bluetooth im Vergleich zur konventionellen Verkabelung teuer und es besteht hierbei die M{\"o}glichkeit, dass sie ausspioniert werden k{\"o}nnen und so sensible Daten entwendet werden k{\"o}nnen. In dieser Arbeit wird eine alternative Realisierung zu den bestehenden Funksystemen vorgestellt, die aus wenigen Komponenten aufzubauen ist. Es ist eine protokolllose, echtzeitf{\"a}hige {\"U}bertragung m{\"o}glich und somit die transparente Integration in ein Bussystem wie CAN.}, language = {de} } @article{Huening2019, author = {H{\"u}ning, Felix}, title = {Nachr{\"u}stm{\"o}glichkeiten von Dieselfahrzeugen aus technischer Sicht}, series = {Zeitschrift f{\"u}r Verkehrsrecht : NZV}, journal = {Zeitschrift f{\"u}r Verkehrsrecht : NZV}, number = {1}, publisher = {C.H.Beck}, pages = {27 -- 32}, year = {2019}, language = {de} } @inproceedings{EssingholtMeyerKuhnetal.2018, author = {Essingholt, Felix and Meyer, Frederic and Kuhn, Peter and Schmidt, Philip and Benkner, Thorsten and Grabmaier, Anton}, title = {Non-invasive heart beat measurement using microwave resonators}, series = {Proceedings, Vol. 2, Eurosensors 2018 Conference, Graz, Austria, 9-12 September 2018}, booktitle = {Proceedings, Vol. 2, Eurosensors 2018 Conference, Graz, Austria, 9-12 September 2018}, publisher = {MDPI}, address = {Basel}, issn = {2504-3900}, doi = {10.3390/proceedings2131002}, pages = {1002}, year = {2018}, language = {en} } @article{HueningHeuermannWache2018, author = {H{\"u}ning, Felix and Heuermann, Holger and Wache, Franz-Josef}, title = {Wireless CAN without WLAN or Bluetooth}, series = {CAN Newsletter}, journal = {CAN Newsletter}, number = {December 2018}, pages = {44 -- 46}, year = {2018}, abstract = {In two developed concepts, dual-mode radio enables CAN participants to be integrated wirelessly into a CAN network. Constructed from a few components, a protocol-free, real-time transmission and thus transparent integration into CAN is provided.}, language = {en} } @inproceedings{HeuermannHarzheimMuehmel2021, author = {Heuermann, Holger and Harzheim, Thomas and M{\"u}hmel, Marc}, title = {A maritime harmonic radar search and rescue system using passive and active tags}, series = {2020 17th European Radar Conference (EuRAD)}, booktitle = {2020 17th European Radar Conference (EuRAD)}, publisher = {IEEE}, address = {New York, NY}, isbn = {978-2-87487-061-3}, doi = {10.1109/EuRAD48048.2021.00030}, pages = {73 -- 76}, year = {2021}, abstract = {This article introduces a new maritime search and rescue system based on S-band illumination harmonic radar (HR). Passive and active tags have been developed and tested attached to life jackets and a rescue boat. This system was able to detect and range the active tags up to a range of 5800 m in tests on the Baltic Sea with an antenna input power of only 100 W. All electronic GHz components of the system, excluding the S-band power amplifier, were custom developed for this purpose. Special attention is given to the performance and conceptual differences between passive and active tags used in the system and integration with a maritime X-band navigation radar is demonstrated.}, language = {en} } @techreport{JaekelKleinBarthetal.1996, author = {Jaekel, C. and Klein, C. and Barth, R. and Roskos, H. and Kyas, G. and Schroeer, M. and H{\"u}ning, Felix}, title = {Dynamik von Nichtgleichgewichtszustaenden in Hochtemperatursupraleitern Abschlussbericht}, pages = {47 Seiten}, year = {1996}, abstract = {Im Projekt wurden mit Hilfe zeitaufgeloester optischer Messtechniken Relaxations-Dynamiken von optisch angeregten Ladungstraegern und Hochfrequenzeigenschaften von Hochtemperatursupraleitern untersucht. Oberhalb der Sprungtemperatur wurden die Elektron-Phonon-Kopplungskonstanten fuer YBCO und BSCCO bestimmt. Dabei wurde erstmalig ein direkter Zusammenhang zwischen der Sprungtemperatur und der Kopplungstaerke gefunden. Der Kopplungsmechanismus enthaelt sowohl phononische als auch elektronische (spindynamische) Anteile. Unterhalb von T_c wird die Dynamik durch Aufbrechen und Rekombination von Cooper-Paaren bestimmt. Bei den Arbeiten zu den kohaerenten Phononen wurde ein Modell entwickelt, das das 'Anwerfen' der Phononen und das Amplitudenverhalten unterhalb der Sprungtemperatur erklaert. Als begleitende Untersuchungen wurden breitbandige Hochfrequenz-Messungen vorgenommen. Die Methode erlaubt die Untersuchung von Ladungstraegerdichten und von Streumechanismen. Erstmalig wurde in verspannten YBCO-Duennfilmen eine starke temperaturabhaengige Resonanz-Absorption beobachtet, die als Josephson-Plasmaresonanz an intrinsischen Kontakten identifiziert werden konnte. Die Nutzbarkeit dieser Kontakte fuer Bauelemente wurde durch einen Mikrowellendetektor demonstriert. Durch den Nachweis von emittierter gepulster Strahlung aus einer stromdurchflossenen supraleitenden Bruecke nach optischer Anregung wurde erstmals die Einsatzmoeglichkeit von HTSL fuer schnelle optische Schalter demonstriert. Es wurde gezeigt, dass die Schaltgeschwindigkeit eine direkte Folge der Ladungstraegerdynamik ist.}, language = {de} } @inproceedings{FerreinMeessenLimpertetal.2021, author = {Ferrein, Alexander and Meeßen, Marcus and Limpert, Nicolas and Schiffer, Stefan}, title = {Compiling ROS schooling curricula via contentual taxonomies}, series = {Robotics in Education}, booktitle = {Robotics in Education}, editor = {Lepuschitz, Wilfried}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-67411-3}, doi = {10.1007/978-3-030-67411-3_5}, pages = {49 -- 60}, year = {2021}, abstract = {The Robot Operating System (ROS) is the current de-facto standard in robot middlewares. The steadily increasing size of the user base results in a greater demand for training as well. User groups range from students in academia to industry professionals with a broad spectrum of developers in between. To deliver high quality training and education to any of these audiences, educators need to tailor individual curricula for any such training. In this paper, we present an approach to ease compiling curricula for ROS trainings based on a taxonomy of the teaching contents. The instructor can select a set of dedicated learning units and the system will automatically compile the teaching material based on the dependencies of the units selected and a set of parameters for a particular training. We walk through an example training to illustrate our work.}, language = {en} } @article{RoepkeKoehlerDruryetal.2020, author = {Roepke, Rene and K{\"o}hler, Klemens and Drury, Vincent and Schroeder, Ulrik and Wolf, Martin and Meyer, Ulrike}, title = {A pond full of phishing games - analysis of learning games for anti-phishing education}, series = {Model-driven Simulation and Training Environments for Cybersecurity. MSTEC 2020}, journal = {Model-driven Simulation and Training Environments for Cybersecurity. MSTEC 2020}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-62433-0}, doi = {10.1007/978-3-030-62433-0_32020}, pages = {41 -- 60}, year = {2020}, abstract = {Game-based learning is a promising approach to anti-phishing education, as it fosters motivation and can help reduce the perceived difficulty of the educational material. Over the years, several prototypes for game-based applications have been proposed, that follow different approaches in content selection, presentation, and game mechanics. In this paper, a literature and product review of existing learning games is presented. Based on research papers and accessible applications, an in-depth analysis was conducted, encompassing target groups, educational contexts, learning goals based on Bloom's Revised Taxonomy, and learning content. As a result of this review, we created the publications on games (POG) data set for the domain of anti-phishing education. While there are games that can convey factual and conceptual knowledge, we find that most games are either unavailable, fail to convey procedural knowledge or lack technical depth. Thus, we identify potential areas of improvement for games suitable for end-users in informal learning contexts.}, language = {en} } @inproceedings{HoegenDonckerRuetters2020, author = {Hoegen, Anne von and Doncker, Rik W. De and R{\"u}tters, Ren{\´e}}, title = {Teaching Digital Control of Operational Amplifier Processes with a LabVIEW Interface and Embedded Hardware}, series = {2020 23rd International Conference on Electrical Machines and Systems (ICEMS)}, booktitle = {2020 23rd International Conference on Electrical Machines and Systems (ICEMS)}, publisher = {IEEE}, address = {New York, NY}, doi = {10.23919/ICEMS50442.2020.9290928}, pages = {1117 -- 1122}, year = {2020}, abstract = {Control engineering theory is hard to grasp for undergraduates during the first semesters, as it deals with the dynamical behavior of systems also in combination with control strategies on an abstract level. Therefore, operational amplifier (OpAmp) processes are reasonable and very effective systems to connect mathematical description with actual system's behavior. In this paper, we present an experiment for a laboratory session in which an embedded system, driven by a LabVIEW human machine interface (HMI) via USB, controls the analog circuits.With this setup we want to show the possibility of firstly, analyzing a first order process and secondly, designing a P-and PI-controller. Thereby, the theory of control engineering is always applied to the empirical results in order to break down the abstract level for the students.}, language = {en} } @incollection{SchubaHoefken2022, author = {Schuba, Marko and H{\"o}fken, Hans-Wilhelm}, title = {Cybersicherheit in Produktion, Automotive und intelligenten Geb{\"a}uden}, series = {IT-Sicherheit - Technologien und Best Practices f{\"u}r die Umsetzung im Unternehmen}, booktitle = {IT-Sicherheit - Technologien und Best Practices f{\"u}r die Umsetzung im Unternehmen}, publisher = {Carl Hanser Verlag}, address = {M{\"u}nchen}, isbn = {978-3-446-47223-5}, doi = {10.3139/9783446473478.012}, pages = {193 -- 218}, year = {2022}, language = {de} } @incollection{EnglaenderKaminskiSchuba2022, author = {Engl{\"a}nder, Jacques and Kaminski, Lars and Schuba, Marko}, title = {Informationssicherheitsmanagement}, series = {Digitalisierungs- und Informationsmanagement}, booktitle = {Digitalisierungs- und Informationsmanagement}, publisher = {Springer Vieweg}, address = {Berlin}, isbn = {978-3-662-63757-9}, doi = {10.1007/978-3-662-63758-6_15}, pages = {373 -- 398}, year = {2022}, abstract = {Daten und Informationen sind die wichtigsten Ressourcen vieler Unternehmen und m{\"u}ssen daher entsprechend gesch{\"u}tzt werden. Getrieben durch die erh{\"o}hte Vernetzung von Informationstechnologie, die h{\"o}here Offenheit infolge datengetriebener Dienstleistungen und eine starke Zunahme an Datenquellen, r{\"u}cken die Gefahren von Informationsdiebstahl, -manipulation und -verlust in den Fokus von produzierenden Unternehmen. Auf dem Weg zum lern- und wandlungsf{\"a}higen Unternehmen kann dies zu einem großen Hindernis werden, da einerseits zu hohe Sicherheitsanforderungen neue Entwicklungen beschr{\"a}nken, andererseits wegen des Mangels an ausreichenden Informationssicherheitskonzepten Unternehmen weniger Innovationen wagen. Deshalb bedarf es individuell angepasster Konzepte f{\"u}r die Bereiche IT-Security, IT-Safety und Datenschutz f{\"u}r vernetzte Produkte, Produktion und Arbeitspl{\"a}tze. Bei der Entwicklung und Durchsetzung dieser Konzepte steht der Faktor Mensch im Zentrum aller {\"U}berlegungen. In diesem Kapitel wird dargestellt, wie der Faktor Mensch bei der Erstellung von Informationssicherheitskonzepten in verschiedenen Phasen zu beachten ist. Beginnend mit der Integration von Informationssystemen und damit verbundenen Sicherheitsmaßnahmen, {\"u}ber die Administration, bis hin zur Anwendung durch den Endnutzer, werden Methoden beschrieben, die den Menschen, verbunden mit seinem Mehrwert wie auch den Risiken, einschließen. Dabei werden sowohl Grundlagen aufgezeigt als auch Konzepte vorgestellt, mit denen Entscheider in der Unternehmens-IT Leitlinien f{\"u}r die Informationssicherheit festlegen k{\"o}nnen.}, language = {de} } @inproceedings{SchubaHoefkenLinzbach2022, author = {Schuba, Marko and H{\"o}fken, Hans-Wilhelm and Linzbach, Sophie}, title = {An ICS Honeynet for Detecting and Analyzing Cyberattacks in Industrial Plants}, series = {2021 International Conference on Electrical, Computer and Energy Technologies (ICECET)}, booktitle = {2021 International Conference on Electrical, Computer and Energy Technologies (ICECET)}, publisher = {IEEE}, isbn = {978-1-6654-4231-2}, doi = {10.1109/ICECET52533.2021.9698746}, pages = {6 Seiten}, year = {2022}, abstract = {Cybersecurity of Industrial Control Systems (ICS) is an important issue, as ICS incidents may have a direct impact on safety of people or the environment. At the same time the awareness and knowledge about cybersecurity, particularly in the context of ICS, is alarmingly low. Industrial honeypots offer a cheap and easy to implement way to raise cybersecurity awareness and to educate ICS staff about typical attack patterns. When integrated in a productive network, industrial honeypots may not only reveal attackers early but may also distract them from the actual important systems of the network. Implementing multiple honeypots as a honeynet, the systems can be used to emulate or simulate a whole Industrial Control System. This paper describes a network of honeypots emulating HTTP, SNMP, S7communication and the Modbus protocol using Conpot, IMUNES and SNAP7. The nodes mimic SIMATIC S7 programmable logic controllers (PLCs) which are widely used across the globe. The deployed honeypots' features will be compared with the features of real SIMATIC S7 PLCs. Furthermore, the honeynet has been made publicly available for ten days and occurring cyberattacks have been analyzed}, language = {en} } @inproceedings{ChristianMontagSchubaetal.2018, author = {Christian, Esser and Montag, Tim and Schuba, Marko and Allhof, Manuel}, title = {Future critical infrastructure and security - cyberattacks on charging stations}, series = {31st International Electric Vehicle Symposium \& Exhibition and International Electric Vehicle Technology Conference (EVS31 \& EVTeC 2018)}, booktitle = {31st International Electric Vehicle Symposium \& Exhibition and International Electric Vehicle Technology Conference (EVS31 \& EVTeC 2018)}, publisher = {Society of Automotive Engineers of Japan (JSAE)}, address = {Tokyo}, isbn = {978-1-5108-9157-9}, pages = {665 -- 671}, year = {2018}, language = {en} } @inproceedings{MaikeLenzWolf2014, author = {Maike, M{\"u}ller and Lenz, Laura and Wolf, Martin}, title = {Steigerung der Effektivit{\"a}t durch Prozessmodellierungs-Tools - {\"A}nderbarkeit und Transparenz von Prozessen am Beispiel der Business Simulation Apollo 13}, series = {Informatik 2014}, booktitle = {Informatik 2014}, publisher = {Gesellschaft f{\"u}r Informatik e.V.}, address = {Bonn}, isbn = {978-3-88579-626-8}, issn = {1617-5468}, pages = {357 -- 369}, year = {2014}, abstract = {Die Nutzung von Prozessmodellierungsmethoden oder - werkzeugen kann erheblichen Einfluss auf die Effektivit{\"a}t von Prozessen haben. Das gilt insbesondere f{\"u}r Situationen, in denen Personen unter Stress stehen oder unge{\"u}bt sind. In diesen F{\"a}llen geben Prozessmodelle konkrete Empfehlungen, nach denen sich die handelnden Personen richten k{\"o}nnten. In Experimenten mit der Business-Simulation Apollo 13 haben wir den Effekt eines Einsatzes von Prozessmodellierungsmethoden und -werkzeugen untersucht. Bereits bekannte Theorien (z.B. {\"u}ber geeignete Verh{\"a}ltnisse von Kommunikationsinhalten) konnten best{\"a}tigt werden. Dar{\"u}ber hinaus haben wir eine besondere Bedeutung der {\"U}bertragbarkeit von Prozessmodellen in konkrete Handlungen identifiziert.}, language = {de} } @techreport{ThomaLaarmannMerkensetal.2020, author = {Thoma, Andreas and Laarmann, Lukas and Merkens, Torsten and Franzke, Till and M{\"o}hren, Felix and Buttermann, Lilly and van der Weem, Dirk and Fischer, Maximilian and Misch, Philipp and B{\"o}hme, Mirijam and R{\"o}th, Thilo and Hebel, Christoph and Ritz, Thomas and Franke, Marina and Braun, Carsten}, title = {Entwicklung eines intermodalen Mobilit{\"a}tskonzeptes f{\"u}r die Pilotregion NRW/Rhein-Maas Euregio und Schaffung voller Kundenakzeptanz durch Transfer von Standards aus dem PKW-Bereich auf ein Flugtaxi : Schlussbericht : Projektakronym: SkyCab (Kategorie B) : Laufzeit in Monaten: 6 : Hauptthema: Kategorie B: Innovative Ideen mit Bezug zu UAS/Flugtaxis}, publisher = {FH Aachen}, address = {Aachen}, pages = {97 Seiten}, year = {2020}, language = {de} } @article{Wolf2000, author = {Wolf, Martin}, title = {Groupware related task design}, series = {ACM SIGGROUP Bulletin}, volume = {21}, journal = {ACM SIGGROUP Bulletin}, number = {2}, issn = {2372-7403}, doi = {10.1145/605660.605662}, pages = {5 -- 8}, year = {2000}, abstract = {his report summarizes the results of a workshop on Groupware related task design which took place at the International Conference on Supporting Group Work Group'99, Arizona, from 14 th to 17 th November 1999. The workshop was addressed to people from different viewpoints, backgrounds, and domains: - Researchers dealing with questions of task analysis and task modeling for Groupware application from an academic point of view. They may contribute modelbased design approaches or theoretically oriented work - Practitioners with experience in the design and everyday use of groupware systems. They might refer to the practical side of the topic: "real" tasks, "real" problems, "real" users, etc.}, language = {en} } @inproceedings{KoenigVoelkerWolf2018, author = {K{\"o}nig, Johannes Alexander and V{\"o}lker, Veronika and Wolf, Martin}, title = {The user-focused storybuilding framework for competence developing games - a design-framework considering the basics of an educational game's story}, series = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, booktitle = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, isbn = {978-1-61208-616-3}, pages = {98 -- 106}, year = {2018}, abstract = {During the development of a Competence Developing Game's (CDG) story it is indispensable to understand the target audience. Thereby, CDGs stories represent more than just the plot. The Story is about the Setting, the Characters and the Plot. As a toolkit to support the development of such a story, this paper introduces the UserFocused Storybuilding (short UFoS) Framework for CDGs. The Framework and its utilization will be explained, followed by a description of its development and derivation, including an empirical study. In addition, to simplify the Framework use regarding the CDG's target audience, a new concept of Nine Psychographic Player Types will be explained. This concept of Player Types provides an approach to handle the differences in between players during the UFoS Framework use. Thereby, this article presents a unique approach to the development of target group-differentiated CDGs stories.}, language = {en} } @inproceedings{DowidatKoenigWolf2017, author = {Dowidat, Linda and K{\"o}nig, Johannes Alexander and Wolf, Martin}, title = {The motivational competence developing game framework}, series = {Mensch und Computer 2017 - Tagungsband}, booktitle = {Mensch und Computer 2017 - Tagungsband}, publisher = {Gesellschaft f{\"u}r Informatik e.V.}, address = {Regensburg}, doi = {10.18420/muc2017-mci-0130}, pages = {15 -- 26}, year = {2017}, abstract = {Competence Developing Games (CDGs) are a new concept of how to think about games with serious intentions. In order to emphasize on this topic, a new framework has been developed. It basically relies on learning and motivation theories. This 'motivational Competence Developing Game Framework' demonstrates how it is possible to use these theories in a CDG development process. The theoretical derivation and use of the framework is explained in this paper.}, language = {en} } @inproceedings{KoenigWolf2018, author = {K{\"o}nig, Johannes Alexander and Wolf, Martin}, title = {Cybersecurity awareness training provided by the competence developing game GHOST}, series = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, booktitle = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, isbn = {978-1-61208-616-3}, pages = {81 -- 87}, year = {2018}, abstract = {This paper introduces a Competence Developing Game (CDG) for the purpose of a cybersecurity awareness training for businesses. The target audience will be discussed in detail to understand their requirements. It will be explained why and how a mix of business simulation and serious game meets these stakeholder requirements. It will be shown that a tablet and touchscreen based approach is the most suitable solution. In addition, an empirical study will be briefly presented. The study was carried out to examine how an interaction system for a 3D-tablet based CDG has to be designed, to be manageable for non-game experienced employees. Furthermore, it will be explained which serious content is necessary for a Cybersecurity awareness training CDG and how this content is wrapped in the game}, language = {en} } @article{HeuermannEmmrichBongartz2022, author = {Heuermann, Holger and Emmrich, Thomas and Bongartz, Simon}, title = {Microwave spark plug to support ignitions with high compression ratios}, series = {IEEE Transactions on Plasma Science}, journal = {IEEE Transactions on Plasma Science}, number = {Early Access}, publisher = {IEEE}, issn = {1939-9375}, doi = {10.1109/TPS.2022.3183690}, pages = {1 -- 6}, year = {2022}, abstract = {Upcoming gasoline engines should run with a larger number of fuels beginning from petrol over methanol up to gas by a wide range of compression ratios and a homogeneous charge. In this article, the microwave (MW) spark plug, based on a high-speed frequency hopping system, is introduced as a solution, which can support a nitrogen compression ratio up to 1:39 in a chamber and more. First, an overview of the high-speed frequency hopping MW ignition and operation system as well as the large number of applications are presented. Both gives an understanding of this new base technology for MW plasma generation. Focus of the theoretical part is the explanation of the internal construction of the spark plug, on the achievable of the high voltage generation as well as the high efficiency to hold the plasma. In detail, the development process starting with circuit simulations and ending with the numerical multiphysics field simulations is described. The concept is evaluated with a reference prototype covering the frequency range between 2.40 and 2.48 GHz and working over a large power range from 20 to 200 W. A larger number of different measurements starting by vector hot-S11 measurements and ending by combined working scenarios out of hot temperature, high pressure and charge motion are winding up the article. The limits for the successful pressure tests were given by the pressure chamber. Pressures ranged from 1 to 39 bar and charge motion up to 25 m/s as well as temperatures from 30◦ to 125◦.}, language = {en} } @inproceedings{NeesStengelMeisteretal.2020, author = {Nees, Franz and Stengel, Ingo and Meister, Vera G. and Barton, Thomas and Herrmann, Frank and M{\"u}ller, Christian and Wolf, Martin}, title = {Angewandte Forschung in der Wirtschaftsinformatik 2020 : Tagungsband zur 33. AKWI-Jahrestagung am 14.09.2020, ausgerichtet von der Hochschule Karlsruhe - Wirtschaft und Technik / hrsg. von Franz Nees, Ingo Stengel, Vera G. Meister, Thomas Barton, Frank Herrmann, Christian M{\"u}ller, Martin R. Wolf}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-66-2}, doi = {10.15771/978-3-944330-66-2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13840}, pages = {147 Seiten}, year = {2020}, abstract = {Tagungsbeitr{\"a}ge aus den Bereichen KI, Prozessorganisation und Plattformen f{\"u}r Gesch{\"a}ftsprozesse, Sicherheit und Datenschutz sowie Prototypen und Modelle.}, language = {de} } @inproceedings{WolfBartonHerrmannetal.2019, author = {Wolf, Martin and Barton, Thomas and Herrmann, Frank and Meister, Vera G. and M{\"u}ller, Christian and Seel, Christian}, title = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung vom 15.09.2019 bis 18.09.2019 an der Fachhochschule f{\"u}r Angewandte Wissenschaften Aachen / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian M{\"u}ller, Christian Seel}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-62-4}, doi = {10.15771/978-3-944330-62-4}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13026}, pages = {261 Seiten}, year = {2019}, abstract = {Tagungsbeitr{\"a}ge aus den Bereichen Projektmanagement, Didaktik in der Wirtschaftsinformatik, IT-Sicherheit, Anwendungsf{\"a}lle, Reifegradmodelle, Plattformen f{\"u}r Gesch{\"a}ftsprozesse und Prototypen.}, language = {de} } @inproceedings{MollKoehlerWolf2019, author = {Moll, Florian and K{\"o}hler, Klemens and Wolf, Martin}, title = {Konzeption von IT-Sicherheitsl{\"o}sungen unter ethischen Gesichtspunkten am Beispiel einer Monitoring-App f{\"u}r mobile Endger{\"a}te}, series = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung}, booktitle = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-62-4}, pages = {61 -- 72}, year = {2019}, abstract = {Die steigende Popularit{\"a}t von mobilen Endger{\"a}ten im privaten und gesch{\"a}ftlichen Umfeld geht mit einem Anstieg an Sicherheitsl{\"u}cken und somit potentiellen Angriffsfl{\"a}chen einher. Als ein Element der technischen und organisatorischen Maßnahmen zum Schutz eines Netzwerkes k{\"o}nnen Monitoring-Apps dienen, die unerw{\"u}nschtes Verhalten und Angriffe erkennen. Die automatisierte {\"U}berwachung von Endger{\"a}ten ist jedoch rechtlich und ethisch komplex. Dies in Kombination mit einer hohen Sensibilit{\"a}t der Nutzer und Nutzerinnen dieser Ger{\"a}te in Bezug auf Privatsph{\"a}re, kann zu einer geringen Akzeptanz und Compliance f{\"u}hren. Eine datenschutzrechtlich und ethisch einwandfreie Konzeption solcher Apps bereits im Designprozess f{\"u}hrt zu h{\"o}herer Akzeptanz und verbessert so die Effizienz. Diese Analyse beschreibt M{\"o}glichkeiten zur Umsetzung.}, language = {de} } @inproceedings{BeckerWolf2019, author = {Becker, Willi and Wolf, Martin}, title = {Entwicklung eines Einf{\"u}hrungskonzepts f{\"u}r IT-Service-Management in KMU}, series = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian M{\"u}ller, Christian Seel}, booktitle = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian M{\"u}ller, Christian Seel}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-62-4}, pages = {129 -- 137}, year = {2019}, abstract = {Obwohl es eine Vielzahl von Einf{\"u}hrungskonzepten f{\"u}r ITSM gibt, hat sich bisher keines dieser Konzepte auf breiter Linie durchgesetzt. Das gilt in erh{\"o}htem Maße f{\"u}r ITSM-Einf{\"u}hrungskonzepte f{\"u}r KMU, wohl nicht zuletzt aufgrund der Tatsache, dass der Mehrwert von ITSM f{\"u}r KMU aufgrund der geringeren Gr{\"o}ße der IT-Organisationen nur entsprechend schwieriger generiert werden kann. Mit diesem Beitrag wird ein Einf{\"u}hrungskonzept f{\"u}r ITSM in KMU systematisch hergeleitet. Daf{\"u}r wurden zun{\"a}chst die Treiber und Barrieren von ITSM untersucht, um daraus ein umfassendes Wirkmodell zu entwickeln. Da mit diesem Wirkungsmodell die Einflussfaktoren auf den Erfolg von ITSM in KMU deutlich werden, konnte auf dieser Basis ein Einf{\"u}hrungskonzept abgeleitet werden, welches insbesondere die positiven Effekte unterst{\"u}tzt bzw. verst{\"a}rkt.}, language = {de} } @inproceedings{BertschMeineckeWolfetal.2019, author = {Bertsch, Timo and Meinecke, Matthias and Wolf, Martin and Schmunk, Karina}, title = {Smart-Living-Services nur gegen Daten? Process-Mining als M{\"o}glichkeit zur Steigerung der Akzeptanz!}, series = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian M{\"u}ller, Christian Seel}, booktitle = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian M{\"u}ller, Christian Seel}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-62-4}, pages = {216 -- 226}, year = {2019}, abstract = {Seit Jahren etablieren sich Technologien in unserem Alltag, die mit Hilfe von smarten Komponenten neue Services und Vernetzungsm{\"o}glichkeiten schaffen. Dieses Paper beschreibt die Ergebnisse einer Studie, die die Akzeptanz von IoT-gest{\"u}tzten, smarten Services im privaten Umfeld untersucht. Dabei wird eine zentrale Datenverarbeitung mit automatisierter Erstellung smarter Services der dezentralen Datenverarbeitung mit manueller Serviceerstellung in sieben Kategorien gegen{\"u}bergestellt. Die Auswertung der Studie legt die Forschungsfrage nahe, ob das Nutzerverhalten im Kontext Smart Living nicht auch mit einem dezentralen L{\"o}sungsansatz, und somit unabh{\"a}ngig von großen Unternehmen, analysiert werden kann. Hierf{\"u}r wird im zweiten Teil des Papers die Anwendbarkeit von Process-Mining im Bereich Smart Living untersucht und prototypisch getestet.}, language = {de} } @inproceedings{KoenigKaiserWolf2019, author = {K{\"o}nig, Johannes Alexander and Kaiser, Steffen and Wolf, Martin}, title = {Entwicklung und Evaluierung eines Regeleditors f{\"u}r die grafische Erstellung von „Smart Living Environment"-Services}, series = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian M{\"u}ller, Christian Seel}, booktitle = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian M{\"u}ller, Christian Seel}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-62-4}, pages = {234 -- 243}, year = {2019}, abstract = {In diesem Paper wird die Entwicklung und Evaluation eines grafischen Regeleditors f{\"u}r das Erstellen von „Smart Living Environments"-Services vorgestellt. Daf{\"u}r werden zun{\"a}chst die Deduktion und Implementierung des grafischen Regeleditors erl{\"a}utert. Anschließend wird eine Probandenstudie vorgestellt, in welcher der Mehrwert bezogen auf die Aspekte Zeit, Fehleranf{\"a}lligkeit und Gebrauchstauglichkeit festgestellt wird.}, language = {de} } @inproceedings{WolfKoenig2017, author = {Wolf, Martin and K{\"o}nig, Johannes Alexander}, title = {Competence Developing Games - Ein {\"U}berblick}, series = {INFORMATIK 2017, Lecture Notes in Informatics (LNI), Gesellschaft f{\"u}r Informatik}, booktitle = {INFORMATIK 2017, Lecture Notes in Informatics (LNI), Gesellschaft f{\"u}r Informatik}, editor = {Eibl, Maximilian and Gaedke, Martin}, organization = {Gesellschaft f{\"u}r Informatik}, isbn = {978-3-88579-669-5}, doi = {10.18420/in2017_32}, pages = {385 -- 391}, year = {2017}, abstract = {Es existieren verschiedenste Arten von Spielen, die versuchen, die Motivation einer Spielsituation in einen ernsten Kontext zu {\"u}berf{\"u}hren. In diesem Artikel wird der {\"U}berbegriff „Competence Developing Games" definiert und anhand von Beispielen erl{\"a}utert. Daf{\"u}r werden Erkennungskriterien vorgestellt, entsprechende Spieltypen erl{\"a}utert und eine Zuordnung durch-gef{\"u}hrt.}, language = {de} } @article{FiedlerOrzadaFloeseretal.2022, author = {Fiedler, Thomas M. and Orzada, Stephan and Fl{\"o}ser, Martina and Rietsch, Stefan H. G. and Schmidt, Simon and Stelter, Jonathan K. and Wittrich, Marco and Quick, Harald H. and Bitz, Andreas and Ladd, Mark E.}, title = {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}, series = {NMR in Biomedicine}, volume = {35}, journal = {NMR in Biomedicine}, number = {5}, publisher = {Wiley}, issn = {0952-3480 (Print)}, doi = {10.1002/nbm.4656}, pages = {1 -- 17}, year = {2022}, abstract = {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.}, language = {en} } @article{SchulteTiggesFoersterNikolovskietal.2022, author = {Schulte-Tigges, Joschua and F{\"o}rster, Marco and Nikolovski, Gjorgji and Reke, Michael and Ferrein, Alexander and Kaszner, Daniel and Matheis, Dominik and Walter, Thomas}, title = {Benchmarking of various LiDAR sensors for use in self-driving vehicles in real-world environments}, series = {Sensors}, volume = {22}, journal = {Sensors}, number = {19}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s22197146}, pages = {20 Seiten}, year = {2022}, abstract = {Abstract In this paper, we report on our benchmark results of the LiDAR sensors Livox Horizon, Robosense M1, Blickfeld Cube, Blickfeld Cube Range, Velodyne Velarray H800, and Innoviz Pro. The idea was to test the sensors in different typical scenarios that were defined with real-world use cases in mind, in order to find a sensor that meet the requirements of self-driving vehicles. For this, we defined static and dynamic benchmark scenarios. In the static scenarios, both LiDAR and the detection target do not move during the measurement. In dynamic scenarios, the LiDAR sensor was mounted on the vehicle which was driving toward the detection target. We tested all mentioned LiDAR sensors in both scenarios, show the results regarding the detection accuracy of the targets, and discuss their usefulness for deployment in self-driving cars.}, language = {en} } @article{HoffmannRohrbachUhletal.2022, author = {Hoffmann, Andreas and Rohrbach, Felix and Uhl, Matthias and Ceblin, Maximilian and Bauer, Thomas and Mallah, Marcel and Jacob, Timo and Heuermann, Holger and Kuehne, Alexander J. C.}, title = {Atmospheric pressure plasma-jet treatment of polyacrylonitrile-nonwovens—Stabilization and roll-to-roll processing}, series = {Journal of Applied Polymer Science}, volume = {139}, journal = {Journal of Applied Polymer Science}, number = {37}, publisher = {Wiley}, issn = {0021-8995 (Print)}, doi = {10.1002/app.52887}, pages = {1 -- 9}, year = {2022}, abstract = {Carbon nanofiber nonwovens represent a powerful class of materials with prospective application in filtration technology or as electrodes with high surface area in batteries, fuel cells, and supercapacitors. While new precursor-to-carbon conversion processes have been explored to overcome productivity restrictions for carbon fiber tows, alternatives for the two-step thermal conversion of polyacrylonitrile precursors into carbon fiber nonwovens are absent. In this work, we develop a continuous roll-to-roll stabilization process using an atmospheric pressure microwave plasma jet. We explore the influence of various plasma-jet parameters on the morphology of the nonwoven and compare the stabilized nonwoven to thermally stabilized samples using scanning electron microscopy, differential scanning calorimetry, and infrared spectroscopy. We show that stabilization with a non-equilibrium plasma-jet can be twice as productive as the conventional thermal stabilization in a convection furnace, while producing electrodes of comparable electrochemical performance.}, language = {en} } @inproceedings{WalterElsenMuelleretal.1999, author = {Walter, Peter and Elsen, Ingo and M{\"u}ller, Holger and Kraiss, Karl-Friedrich}, title = {3D object recognition with a specialized mixtures of experts architecture}, series = {IJCNN'99. International Joint Conference on Neural Networks. Proceedings}, booktitle = {IJCNN'99. International Joint Conference on Neural Networks. Proceedings}, publisher = {IEEE}, address = {New York}, isbn = {0-7803-5529-6}, issn = {1098-7576}, doi = {10.1109/IJCNN.1999.836243}, pages = {3563 -- 3568}, year = {1999}, abstract = {Aim of the AXON2 project (Adaptive Expert System for Object Recogniton using Neuml Networks) is the development of an object recognition system (ORS) capable of recognizing isolated 3d objects from arbitrary views. Commonly, classification is based on a single feature extracted from the original image. Here we present an architecture adapted from the Mixtures of Eaqerts algorithm which uses multiple neuml networks to integmte different features. During tmining each neural network specializes in a subset of objects or object views appropriate to the properties of the corresponding feature space. In recognition mode the system dynamically chooses the most relevant features and combines them with maximum eficiency. The remaining less relevant features arz not computed and do therefore not decelerate the-recognition process. Thus, the algorithm is well suited for ml-time applications.}, language = {en} } @article{ElsenKraiss1999, author = {Elsen, Ingo and Kraiss, Karl-Friedrich}, title = {System concept and realization of a scalable neurocomputing architecture}, series = {Systems Analysis Modelling Simulation}, volume = {35}, journal = {Systems Analysis Modelling Simulation}, number = {4}, publisher = {Gordon and Breach Science Publishers}, address = {Amsterdam}, issn = {0232-9298}, pages = {399 -- 419}, year = {1999}, abstract = {This paper describes the realization of a novel neurocomputer which is based on the concepts of a coprocessor. In contrast to existing neurocomputers the main interest was the realization of a scalable, flexible system, which is capable of computing neural networks of arbitrary topology and scale, with full independence of special hardware from the software's point of view. On the other hand, computational power should be added, whenever needed and flexibly adapted to the requirements of the application. Hardware independence is achieved by a run time system which is capable of using all available computing power, including multiple host CPUs and an arbitrary number of neural coprocessors autonomously. The realization of arbitrary neural topologies is provided through the implementation of the elementary operations which can be found in most neural topologies.}, language = {en} } @article{ElsenKraissKrumbiegeletal.1999, author = {Elsen, Ingo and Kraiss, Karl-Friedrich and Krumbiegel, Dirk and Walter, Peter and Wickel, Jochen}, title = {Visual information retrieval for 3D product identification: a midterm report}, series = {KI - K{\"u}nstliche Intelligenz}, volume = {13}, journal = {KI - K{\"u}nstliche Intelligenz}, number = {1}, publisher = {Springer}, address = {Berlin}, issn = {1610-1987}, pages = {64 -- 67}, year = {1999}, language = {en} } @inproceedings{Elsen1998, author = {Elsen, Ingo}, title = {A pixel based approach to view based object recognition with self-organizing neural networks}, series = {IECON'98. Proceedings of the 24th Annual Conference of the IEEE Industrial Electronics Society}, booktitle = {IECON'98. Proceedings of the 24th Annual Conference of the IEEE Industrial Electronics Society}, publisher = {IEEE}, address = {New York}, isbn = {0-7803-4503-7}, doi = {10.1109/IECON.1998.724032}, pages = {2040 -- 2044}, year = {1998}, abstract = {This paper addresses the pixel based classification of three dimensional objects from arbitrary views. To perform this task a coding strategy, inspired by the biological model of human vision, for pixel data is described. The coding strategy ensures that the input data is invariant against shift, scale and rotation of the object in the input domain. The image data is used as input to a class of self organizing neural networks, the Kohonen-maps or self-organizing feature maps (SOFM). To verify this approach two test sets have been generated: the first set, consisting of artificially generated images, is used to examine the classification properties of the SOFMs; the second test set examines the clustering capabilities of the SOFM when real world image data is applied to the network after it has been preprocessed to be invariant against shift, scale and rotation. It is shown that the clustering capability of the SOFM is strongly dependant on the invariance coding of the images.}, language = {en} } @inproceedings{ElsenKraissKrumbiegel1997, author = {Elsen, Ingo and Kraiss, Karl-Friedrich and Krumbiegel, Dirk}, title = {Pixel based 3D object recognition with bidirectional associative memories}, series = {International Conference on Neural Networks 1997}, booktitle = {International Conference on Neural Networks 1997}, publisher = {IEEE}, address = {New York}, isbn = {0-7803-4122-8}, pages = {1679 -- 1684}, year = {1997}, abstract = {This paper addresses the pixel based recognition of 3D objects with bidirectional associative memories. Computational power and memory requirements for this approach are identified and compared to the performance of current computer architectures by benchmarking different processors. It is shown, that the performance of special purpose hardware, like neurocomputers, is between one and two orders of magnitude higher than the performance of mainstream hardware. On the other hand, the calculation of small neural networks is performed more efficiently on mainstream processors. Based on these results a novel concept is developed, which is tailored for the efficient calculation of bidirectional associative memories. The computational efficiency is further enhanced by the application of algorithms and storage techniques which are matched to characteristics of the application at hand.}, language = {en} } @misc{HueningBackes2022, author = {H{\"u}ning, Felix and Backes, Andreas}, title = {Wiegand-Modul}, year = {2022}, abstract = {Ein Wiegand-Modul (110;210;310) umfassend- eine Sensorspule (112;212;312),- einen ersten Wiegand-Draht (116a;216a;316a), der zumindest teilweise innerhalb der Sensorspule (112;212;312) angeordnet ist, und- einen zweiten Wiegand-Draht (116b;216b;316b), der zumindest teilweise innerhalb der Sensorspule (112;212;312) angeordnet ist und sich im Wesentlichen parallel zu dem ersten Wiegand-Draht (116a;216a;316a) erstreckt, ist bekannt.Um eine effiziente Ausnutzung der durch die Ummagnetisierung der Wiegand-Dr{\"a}hte (116a,116b;216a,216b;316a,316b) in die Sensorspule (112;212;312) induzierten elektrischen Energie zu erm{\"o}glichen, sind der erste Wiegand-Draht (116a;216a;316a) und der zweite Wiegand-Draht (116b;216b;316b) bezogen auf eine axiale Richtung der Sensorspule (112;212;312) versetzt zueinander angeordnet.}, language = {de} } @inproceedings{ChircuCzarneckiFriedmannetal.2023, author = {Chircu, Alina and Czarnecki, Christian and Friedmann, Daniel and Pomaskow, Johanna and Sultanow, Eldar}, title = {Towards a Digital Twin of Society}, series = {Proceedings of the 56th Hawaii International Conference on System Sciences 2023}, booktitle = {Proceedings of the 56th Hawaii International Conference on System Sciences 2023}, publisher = {University of Hawai'i}, address = {Honolulu}, isbn = {978-0-9981331-6-4}, pages = {6748 -- 6757}, year = {2023}, abstract = {This paper describes the potential for developing a digital twin of society- a dynamic model that can be used to observe, analyze, and predict the evolution of various societal aspects. Such a digital twin can help governmental agencies and policy makers in interpreting trends, understanding challenges, and making decisions regarding investments or policies necessary to support societal development and ensure future prosperity. The paper reviews related work regarding the digital twin paradigm and its applications. The paper presents a motivating case study- an analysis of opportunities and challenges faced by the German federal employment agency, Bundesagentur f¨ur Arbeit (BA), proposes solutions using digital twins, and describes initial proofs of concept for such solutions.}, language = {en} } @misc{WiegnerVolkerMainzetal.2022, author = {Wiegner, J. and Volker, H. and Mainz, F. and Backes, A. and L{\"o}ken, M. and H{\"u}ning, Felix}, title = {Wiegand-Effect-Powered Wireless IT Sensor Node}, year = {2022}, abstract = {With the growing interest in small distributed sensors for the "Internet of Things", more attention is being paid to energy harvesting techologies. Reducing or eliminating the need for external power sources or batteries make devices more self-sufficient, more reliable, and reduces maintenance requirements. The Wiegand effect is a proven technology for harvesting small amounts of electrical power from mechanical motion.}, language = {en} } @incollection{StollenwerkFranzkeMaureretal.2023, author = {Stollenwerk, Dominik and Franzke, Till and Maurer, Florian and Reinkensmeier, Sebastian and Kim, Franken and Tambornino, Philipp and Haas, Florian and Rieke, Christian and Hermanuz, Andreas and Borchert, J{\"o}rg and Ritz, Thomas and Sander, Volker}, title = {Smarte Lades{\"a}ulen : Netz- und Marktdienliches {\"o}ffentliches Laden}, series = {Towards the New Normal in Mobility : Technische und betriebswirtschaftliche Aspekte}, booktitle = {Towards the New Normal in Mobility : Technische und betriebswirtschaftliche Aspekte}, editor = {Proff, Heike}, publisher = {Springer Gabler}, address = {Wiesbaden}, isbn = {978-3-658-39437-0 (Print)}, doi = {10.1007/978-3-658-39438-7_18}, pages = {287 -- 304}, year = {2023}, abstract = {Stand 01.01.2022 sind in Deutschland 618.460 elektrisch angetriebene KFZ zugelassen. Insgesamt sind derzeit 48.540.878 KFZ zugelassen, was einer Elektromobilit{\"a}tsquote von ca. 1,2 \% entspricht. Derzeit werden Elektromobile {\"u}ber Ladestationen oder Steckdosen mit dem Stromnetz verbunden und {\"u}blicherweise mit der vollen Ladekapazit{\"a}t des Anschlusses aufgeladen, bis das Batteriemanagementsystem des Fahrzeugs abh{\"a}ngig vom Ladezustand der Batterie die Ladeleistung reduziert.}, language = {de} } @inproceedings{AltherrConzenElsenetal.2023, author = {Altherr, Lena and Conzen, Max and Elsen, Ingo and Frauenrath, Tobias and Lyrmann, Andreas}, title = {Sensor retrofitting of existing buildings in an interdisciplinary teaching project at university level}, series = {Tagungsband AALE 2023 : mit Automatisierung gegen den Klimawandel}, booktitle = {Tagungsband AALE 2023 : mit Automatisierung gegen den Klimawandel}, editor = {Reiff-Stephan, J{\"o}rg and J{\"a}kel, Jens and Schwarz, Andr{\´e}}, publisher = {le-tex publishing services GmbH}, address = {Leipzig}, isbn = {978-3-910103-01-6}, doi = {10.33968/2023.04}, pages = {31 -- 40}, year = {2023}, abstract = {Existing residential buildings have an average lifetime of 100 years. Many of these buildings will exist for at least another 50 years. To increase the efficiency of these buildings while keeping costs at reasonable rates, they can be retrofitted with sensors that deliver information to central control units for heating, ventilation and electricity. This retrofitting process should happen with minimal intervention into existing infrastructure and requires new approaches for sensor design and data transmission. At FH Aachen University of Applied Sciences, students of different disciplines work together to learn how to design, build, deploy and operate such sensors. The presented teaching project already created a low power design for a combined CO2, temperature and humidity measurement device that can be easily integrated into most home automation systems}, language = {en} } @inproceedings{DeyElsenFerreinetal.2021, author = {Dey, Thomas and Elsen, Ingo and Ferrein, Alexander and Frauenrath, Tobias and Reke, Michael and Schiffer, Stefan}, title = {CO2 Meter: a do-it-yourself carbon dioxide measuring device for the classroom}, series = {PETRA '21: Proceedings of the 14th Pervasive Technologies Related to Assistive Environments Conference}, booktitle = {PETRA '21: Proceedings of the 14th Pervasive Technologies Related to Assistive Environments Conference}, editor = {Makedon, Fillia}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {9781450387927}, doi = {10.1145/3453892.3462697}, pages = {292 -- 299}, year = {2021}, abstract = {In this paper we report on CO2 Meter, a do-it-yourself carbon dioxide measuring device for the classroom. Part of the current measures for dealing with the SARS-CoV-2 pandemic is proper ventilation in indoor settings. This is especially important in schools with students coming back to the classroom even with high incidents rates. Static ventilation patterns do not consider the individual situation for a particular class. Influencing factors like the type of activity, the physical structure or the room occupancy are not incorporated. Also, existing devices are rather expensive and often provide only limited information and only locally without any networking. This leaves the potential of analysing the situation across different settings untapped. Carbon dioxide level can be used as an indicator of air quality, in general, and of aerosol load in particular. Since, according to the latest findings, SARS-CoV-2 can be transmitted primarily in the form of aerosols, carbon dioxide may be used as a proxy for the risk of a virus infection. Hence, schools could improve the indoor air quality and potentially reduce the infection risk if they actually had measuring devices available in the classroom. Our device supports schools in ventilation and it allows for collecting data over the Internet to enable a detailed data analysis and model generation. First deployments in schools at different levels were received very positively. A pilot installation with a larger data collection and analysis is underway.}, language = {en} } @inproceedings{ElsenSchmalzbauer2011, author = {Elsen, Ingo and Schmalzbauer, Michael}, title = {Messsystematik zur Steuerung der Produkt- und Prozessqualit{\"a}t in Systemintegrationsprojekten - ein Erfahrungsbericht}, series = {Software Engineering 2011 - Fachtagung des GI-Fachbereichs Softwaretechnik, 21. - 25. Februar 2011 in Karlsruhe}, booktitle = {Software Engineering 2011 - Fachtagung des GI-Fachbereichs Softwaretechnik, 21. - 25. Februar 2011 in Karlsruhe}, editor = {Reussner, Ralf and Grund, Matthias and Andreas, Oberweis and Tichy, Walter}, publisher = {Gesellschaft f{\"u}r Informatik eV}, address = {Bonn}, isbn = {9783885792772}, issn = {1617-5468}, pages = {1 Seite}, year = {2011}, abstract = {Der Erfolg eines Softwarenentwicklungsprojektes insbesondere eines Systemintegrationsprojektes wird mit der Erf{\"u}llung des „Teufelsdreiecks", „In-Time", „In-Budget", „In-Quality" gemessen. Hierzu ist die Kenntnis der Software- und Prozessqualit{\"a}t essenziell, um die Einhaltung der Qualit{\"a}tskriterien festzustellen, aber auch, um eine Vorhersage hinsichtlich Termin- und Budgettreue zu treffen. Zu diesem Zweck wurde in der T-Systems Systems Integration ein System aus verschiedenen Key Performance Indikatoren entworfen und in der Organisation implementiert, das genau das leistet und die Kriterien f{\"u}r CMMI Level 3 erf{\"u}llt.}, language = {de} } @inproceedings{ElsenHawariJohnen2010, author = {Elsen, Ingo and Hawari, Asma and Johnen, Uwe}, title = {Produktkernel in der Systemintegration (Erfahrungsbericht aus der Praxis)}, series = {Vom Projekt zum Produkt - Fachtagung des GI-Fachausschusses Management der Anwendungsentwicklung und -wartung im Fachbereich Wirtschaftsinformatik (WI-MAW), 1. - 3. Dezember 2010 in Aachen}, booktitle = {Vom Projekt zum Produkt - Fachtagung des GI-Fachausschusses Management der Anwendungsentwicklung und -wartung im Fachbereich Wirtschaftsinformatik (WI-MAW), 1. - 3. Dezember 2010 in Aachen}, editor = {Pietsch, Wolfram and Krams, Benedikt}, publisher = {Gesellschaft f{\"u}r Informatik eV}, address = {Bonn}, isbn = {9783885792727}, issn = {1617-5468}, pages = {93 -- 102}, year = {2010}, abstract = {In der Vergangenheit basierten große Systemintegrationsprojekte in der Regel auf Individualentwicklungen f{\"u}r einzelne Kunden. Getrieben durch Kostendruck steigt aber der Bedarf nach standardisierten L{\"o}sungen, die gleichzeitig die individuellen Anforderungen des jeweiligen Umfelds ber{\"u}cksichtigen. T-Systems GEI GmbH wird beiden Anforderungen mit Produktkerneln gerecht. Neben den technischen Aspekten der Kernelentwicklung spielen besonders organisatorische Aspekte eine Rolle, um Kernel effizient und qualitativ hochwertig zu entwickeln, ohne deren Funktionalit{\"a}ten ins Uferlose wachsen zu lassen. Umgesetzt hat T-Systems dieses Konzept f{\"u}r Flughafeninformationssysteme. Damit kann dem wachsenden Bedarf der Flughafenbetreiber nach einer effizienten und kosteng{\"u}nstigen Softwarel{\"o}sung zur Unterst{\"u}tzung Ihrer Gesch{\"a}ftsprozesse entsprochen werden.}, language = {de} } @article{ElsenHartungHornetal.2001, author = {Elsen, Ingo and Hartung, Frank and Horn, Uwe and Kampmann, Markus and Peters, Liliane}, title = {Streaming technology in 3G mobile communication systems}, series = {Computer : innovative technology for computer professionals}, volume = {34}, journal = {Computer : innovative technology for computer professionals}, number = {9 Seiten}, editor = {Voas, Jeffrey}, publisher = {IEEE}, address = {New York}, issn = {0018-9162}, pages = {46 -- 52}, year = {2001}, abstract = {Third-generation mobile communication systems will combine standardized streaming with a range of unique services to provide high-quality Internet content that meets the specific needs of the rapidly growing mobile market.}, language = {en} } @phdthesis{Elsen2000, author = {Elsen, Ingo}, title = {Ansichtenbasierte 3D-Objekterkennung mit erweiterten selbstorganisierenden Merkmalskarten}, publisher = {VDI-Verlag}, address = {D{\"u}sseldorf}, isbn = {978-3-18-363110-0}, issn = {0341-1796}, pages = {VIII, 140 S. : Ill., graph. Darst.}, year = {2000}, language = {de} } @inproceedings{ViehmannLimpertHofmannetal.2023, author = {Viehmann, Tarik and Limpert, Nicolas and Hofmann, Till and Henning, Mike and Ferrein, Alexander and Lakemeyer, Gerhard}, title = {Winning the RoboCup logistics league with visual servoing and centralized goal reasoning}, series = {RoboCup 2022: Robot World Cup XXV}, booktitle = {RoboCup 2022: Robot World Cup XXV}, editor = {Eguchi, Amy and Lau, Nuno and Paetzel-Pr{\"u}smann, Maike and Wanichanon, Thanapat}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-28468-7 (Print)}, doi = {https://doi.org/10.1007/978-3-031-28469-4_25}, pages = {300 -- 312}, year = {2023}, abstract = {The RoboCup Logistics League (RCLL) is a robotics competition in a production logistics scenario in the context of a Smart Factory. In the competition, a team of three robots needs to assemble products to fulfill various orders that are requested online during the game. This year, the Carologistics team was able to win the competition with a new approach to multi-agent coordination as well as significant changes to the robot's perception unit and a pragmatic network setup using the cellular network instead of WiFi. In this paper, we describe the major components of our approach with a focus on the changes compared to the last physical competition in 2019.}, language = {en} } @inproceedings{NeugebauerBrutschyMeyeretal.2014, author = {Neugebauer, Georg and Brutschy, Lucas and Meyer, Ulrike and Wetzel, Susanne}, title = {Privacy-preserving multi-party reconciliation secure in the malicious model}, series = {DPM 2013, SETOP 2013: Data Privacy Management and Autonomous Spontaneous Security}, booktitle = {DPM 2013, SETOP 2013: Data Privacy Management and Autonomous Spontaneous Security}, editor = {Garcia-Alfaro, Joaquin and Lioudakis, Georgios and Cuppens-Boulahia, Nora and Foley, Simon and Fitzgerald, William M.}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-642-54567-2 (Print)}, doi = {10.1007/978-3-642-54568-9_12}, pages = {178 -- 193}, year = {2014}, abstract = {The problem of fair and privacy-preserving ordered set reconciliation arises in a variety of applications like auctions, e-voting, and appointment reconciliation. While several multi-party protocols have been proposed that solve this problem in the semi-honest model, there are no multi-party protocols that are secure in the malicious model so far. In this paper, we close this gap. Our newly proposed protocols are shown to be secure in the malicious model based on a variety of novel non-interactive zero-knowledge-proofs. We describe the implementation of our protocols and evaluate their performance in comparison to protocols solving the problem in the semi-honest case.}, language = {en} } @inproceedings{NethSchubaBrodkorbetal.2023, author = {Neth, Jannik and Schuba, Marko and Brodkorb, Karsten and Neugebauer, Georg and H{\"o}ner, Tim and Hack, Sacha}, title = {Digital forensics triage app for android}, series = {ARES '23: Proceedings of the 18th International Conference on Availability, Reliability and Security}, booktitle = {ARES '23: Proceedings of the 18th International Conference on Availability, Reliability and Security}, publisher = {ACM}, isbn = {9798400707728}, doi = {10.1145/3600160.3605017}, pages = {6 Seiten}, year = {2023}, abstract = {Digital forensics of smartphones is of utmost importance in many criminal cases. As modern smartphones store chats, photos, videos etc. that can be relevant for investigations and as they can have storage capacities of hundreds of gigabytes, they are a primary target for forensic investigators. However, it is exactly this large amount of data that is causing problems: extracting and examining the data from multiple phones seized in the context of a case is taking more and more time. This bears the risk of wasting a lot of time with irrelevant phones while there is not enough time left to analyze a phone which is worth examination. Forensic triage can help in this case: Such a triage is a preselection step based on a subset of data and is performed before fully extracting all the data from the smartphone. Triage can accelerate subsequent investigations and is especially useful in cases where time is essential. The aim of this paper is to determine which and how much data from an Android smartphone can be made directly accessible to the forensic investigator - without tedious investigations. For this purpose, an app has been developed that can be used with extremely limited storage of data in the handset and which outputs the extracted data immediately to the forensic workstation in a human- and machine-readable format.}, language = {en} } @inproceedings{ArndtConzenElsenetal.2023, author = {Arndt, Tobias and Conzen, Max and Elsen, Ingo and Ferrein, Alexander and Galla, Oskar and K{\"o}se, Hakan and Schiffer, Stefan and Tschesche, Matteo}, title = {Anomaly detection in the metal-textile industry for the reduction of the cognitive load of quality control workers}, series = {PETRA '23: Proceedings of the 16th International Conference on PErvasive Technologies Related to Assistive Environments}, booktitle = {PETRA '23: Proceedings of the 16th International Conference on PErvasive Technologies Related to Assistive Environments}, publisher = {ACM}, isbn = {9798400700699}, doi = {10.1145/3594806.3596558}, pages = {535 -- 542}, year = {2023}, abstract = {This paper presents an approach for reducing the cognitive load for humans working in quality control (QC) for production processes that adhere to the 6σ -methodology. While 100\% QC requires every part to be inspected, this task can be reduced when a human-in-the-loop QC process gets supported by an anomaly detection system that only presents those parts for manual inspection that have a significant likelihood of being defective. This approach shows good results when applied to image-based QC for metal textile products.}, language = {en} } @inproceedings{ZaehlTheisWolfetal.2023, author = {Z{\"a}hl, Philipp M. and Theis, Sabine and Wolf, Martin and K{\"o}hler, Klemens}, title = {Teamwork in software development and what personality has to do with it - an overview}, series = {Virtual, Augmented and Mixed Reality}, booktitle = {Virtual, Augmented and Mixed Reality}, editor = {Chen, Jessie Y. C. and Fragomeni, Gino}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-35633-9 (Print)}, doi = {10.1007/978-3-031-35634-6_10}, pages = {130 -- 153}, year = {2023}, abstract = {Due to the increasing complexity of software projects, software development is becoming more and more dependent on teams. The quality of this teamwork can vary depending on the team composition, as teams are always a combination of different skills and personality types. This paper aims to answer the question of how to describe a software development team and what influence the personality of the team members has on the team dynamics. For this purpose, a systematic literature review (n=48) and a literature search with the AI research assistant Elicit (n=20) were conducted. Result: A person's personality significantly shapes his or her thinking and actions, which in turn influences his or her behavior in software development teams. It has been shown that team performance and satisfaction can be strongly influenced by personality. The quality of communication and the likelihood of conflict can also be attributed to personality.}, language = {en} } @incollection{EggertZaehlWolfetal.2023, author = {Eggert, Mathias and Z{\"a}hl, Philipp M. and Wolf, Martin R. and Haase, Martin}, title = {Applying leaderboards for quality improvement in software development projects}, series = {Software Engineering for Games in Serious Contexts}, booktitle = {Software Engineering for Games in Serious Contexts}, editor = {Cooper, Kendra M.L. and Bucchiarone, Antonio}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-33337-8 (Print)}, doi = {10.1007/978-3-031-33338-5_11}, pages = {243 -- 263}, year = {2023}, abstract = {Software development projects often fail because of insufficient code quality. It is now well documented that the task of testing software, for example, is perceived as uninteresting and rather boring, leading to poor software quality and major challenges to software development companies. One promising approach to increase the motivation for considering software quality is the use of gamification. Initial research works already investigated the effects of gamification on software developers and come to promising. Nevertheless, a lack of results from field experiments exists, which motivates the chapter at hand. By conducting a gamification experiment with five student software projects and by interviewing the project members, the chapter provides insights into the changing programming behavior of information systems students when confronted with a leaderboard. The results reveal a motivational effect as well as a reduction of code smells.}, language = {en} } @article{KowalewskiBragardHueningetal.2023, author = {Kowalewski, Paul and Bragard, Michael and H{\"u}ning, Felix and De Doncker, Rik W.}, title = {An inexpensive Wiegand-sensor-based rotary encoder without rotating magnets for use in electrical drives}, series = {IEEE Transactions on Instrumentation and Measurement}, journal = {IEEE Transactions on Instrumentation and Measurement}, publisher = {IEEE}, issn = {0018-9456 (Print)}, doi = {10.1109/TIM.2023.3326166}, pages = {10 Seiten}, year = {2023}, abstract = {This paper introduces an inexpensive Wiegand-sensor-based rotary encoder that avoids rotating magnets and is suitable for electrical-drive applications. So far, Wiegand-sensor-based encoders usually include a magnetic pole wheel with rotating permanent magnets. These encoders combine the disadvantages of an increased magnet demand and a limited maximal speed due to the centripetal force acting on the rotating magnets. The proposed approach reduces the total demand of permanent magnets drastically. Moreover, the rotating part is manufacturable from a single piece of steel, which makes it very robust and cheap. This work presents the theoretical operating principle of the proposed approach and validates its benefits on a hardware prototype. The presented proof-of-concept prototype achieves a mechanical resolution of 4.5 ° by using only 4 permanent magnets, 2Wiegand sensors and a rotating steel gear wheel with 20 teeth.}, language = {en} } @inproceedings{AlhaskirTschescheLinkeetal.2023, author = {Alhaskir, Mohamed and Tschesche, Matteo and Linke, Florian and Schriewer, Elisabeth and Weber, Yvonne and Wolking, Stefan and R{\"o}hrig, Rainer and Koch, Henner and Kutafina, Ekaterina}, title = {ECG matching: an approach to synchronize ECG datasets for data quality comparisons}, series = {Proceedings of the 68th Annual Meeting of the German Association of Medical Informatics, Biometry, and Epidemiology e.V. (gmds) 2023}, volume = {307}, booktitle = {Proceedings of the 68th Annual Meeting of the German Association of Medical Informatics, Biometry, and Epidemiology e.V. (gmds) 2023}, editor = {R{\"o}hrig, Rainer and Grabe, Niels and Haag, Martin and H{\"u}bner, Ursula and Sax, Ulrich and Schmidt, Carsten Oliver and Sedlmayr, Martin and Zapf, Antonia}, publisher = {IOS Press}, isbn = {978-1-64368-428-4 (Print)}, doi = {10.3233/SHTI230718}, pages = {225 -- 232}, year = {2023}, abstract = {Clinical assessment of newly developed sensors is important for ensuring their validity. Comparing recordings of emerging electrocardiography (ECG) systems to a reference ECG system requires accurate synchronization of data from both devices. Current methods can be inefficient and prone to errors. To address this issue, three algorithms are presented to synchronize two ECG time series from different recording systems: Binned R-peak Correlation, R-R Interval Correlation, and Average R-peak Distance. These algorithms reduce ECG data to their cyclic features, mitigating inefficiencies and minimizing discrepancies between different recording systems. We evaluate the performance of these algorithms using high-quality data and then assess their robustness after manipulating the R-peaks. Our results show that R-R Interval Correlation was the most efficient, whereas the Average R-peak Distance and Binned R-peak Correlation were more robust against noisy data.}, language = {en} } @book{Heuermann2023, author = {Heuermann, Holger}, title = {Hochfrequenztechnik. Komponenten und Mess-, Funk-, RFID- sowie Lokalisierungssysteme}, edition = {4}, publisher = {Springer Fachmedien}, address = {Wiesbaden}, isbn = {978-3-658-37825-7 (Print)}, pages = {XV, 453 Seiten}, year = {2023}, abstract = {Dieses Lehr- und Fachbuch vermittelt anschaulich die Grundlagen der HF-Technik, gibt konkrete Beschreibungen f{\"u}r den Entwurf von linearen Komponenten aus Bauteilen wie auch Leitungen f{\"u}r High-Speed- und HF-Schaltungen. Dem Leser wird vermittelt, wie Bauteile modelliert und Schaltungen synthetisiert und optimiert werden. Mit Hilfe frei verf{\"u}gbarer Simulationssoftware k{\"o}nnen GHz-Schaltungen selbst entwickelt werden. Viele {\"U}bungsbeispiele erm{\"o}glichen die Eigenkontrolle des Wissensstandes. Weiterhin werden komplexe nichtlineare Komponenten wie Hochfrequenzmischer, Oszillatoren und Synthesegeneratoren in ihrer Funktionalit{\"a}t dargestellt. Die neuen Mixed-Mode-Streuparameter sowie deren Leitungs- und Schaltungstechnik f{\"u}r Anwendungen der schnellen Digital- und der modernen HF-Technik sind ausf{\"u}hrlich beschrieben. Es wird auf Systeme f{\"u}r folgende Bereiche eingegangen: Streuparametermesstechnik, verschiedene Funktechniken, UHF-RFID und Lokalisierung- und Ortung. Dem Leser wird somit erm{\"o}glicht, komplexe GHz-Schaltungen insbesondere mit Halbleiter-, SMD- und LTCC-Schaltungen zu entwickeln.}, language = {de} } @book{Heuermann2023, author = {Heuermann, Holger}, title = {Mikrowellentechnik : Feldsimulation, nichtlineare Schaltungstechnik, Komponenten und Subsysteme, Plasmatechnik, Antennen und Ausbreitung}, edition = {2. Auflage}, publisher = {Springer Vieweg}, address = {Wiesbaden}, isbn = {978-3-658-41286-9}, doi = {10.1007/978-3-658-41287-6}, pages = {XVI, 394 Seiten}, year = {2023}, abstract = {Das Lehrbuch behandelt alle Aspekte, die den aktuellen Stand der GHz-Technik betreffen. Das Buch behandelt die verschiedenen numerischen Feldsimulationsverfahren. Mit vielen modernen Themen.}, language = {de} } @inproceedings{EichenbaumNikolovskiMuelhensetal.2023, author = {Eichenbaum, Julian and Nikolovski, Gjorgji and M{\"u}lhens, Leon and Reke, Michael and Ferrein, Alexander and Scholl, Ingrid}, title = {Towards a lifelong mapping approach using Lanelet 2 for autonomous open-pit mine operations}, series = {2023 IEEE 19th International Conference on Automation Science and Engineering (CASE)}, booktitle = {2023 IEEE 19th International Conference on Automation Science and Engineering (CASE)}, publisher = {IEEE}, isbn = {979-8-3503-2069-5 (Online)}, doi = {10.1109/CASE56687.2023.10260526}, pages = {8 Seiten}, year = {2023}, abstract = {Autonomous agents require rich environment models for fulfilling their missions. High-definition maps are a well-established map format which allows for representing semantic information besides the usual geometric information of the environment. These are, for instance, road shapes, road markings, traffic signs or barriers. The geometric resolution of HD maps can be as precise as of centimetre level. In this paper, we report on our approach of using HD maps as a map representation for autonomous load-haul-dump vehicles in open-pit mining operations. As the mine undergoes constant change, we also need to constantly update the map. Therefore, we follow a lifelong mapping approach for updating the HD maps based on camera-based object detection and GPS data. We show our mapping algorithm based on the Lanelet 2 map format and show our integration with the navigation stack of the Robot Operating System. We present experimental results on our lifelong mapping approach from a real open-pit mine.}, language = {en} }