TY - JOUR A1 - Orzada, Stephan A1 - Ladd, Mark E. A1 - Bitz, Andreas T1 - A method to approximate maximum local SAR in multichannel transmit MR systems without transmit phase information JF - Magnetic Resonance in Medicine N2 - 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 Y1 - 2016 U6 - https://doi.org/10.1002/mrm.26398 SN - 1522-2594 VL - 78 IS - 2 SP - 805 EP - 811 PB - International Society for Magnetic Resonance in Medicine ER - TY - JOUR A1 - Chen, Bixia A1 - Schoemberg, Tobias A1 - Kraff, Oliver A1 - Dammann, Philipp A1 - Bitz, Andreas A1 - Schlamann, Marc A1 - Quick, Harald H. A1 - Ladd, Mark E. A1 - Sure, Ulrich A1 - Wrede, Karsten H. T1 - Cranial fixation plates in cerebral magnetic resonance imaging: a 3 and 7 Tesla in vivo image quality study JF - Magnetic Resonance Materials in Physics, Biology and Medicine N2 - 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. Y1 - 2016 U6 - https://doi.org/10.1007/s10334-016-0548-1 SN - 1352-8661 VL - 29 IS - 3 SP - 389 EP - 398 PB - Springer CY - Berlin ER - TY - JOUR A1 - Schmidt, K. A1 - Forkmann, K. A1 - Sinke, C. A1 - Gratz, M. A1 - Bitz, Andreas A1 - Bingel, U. T1 - The differential effect of trigeminal vs. peripheral pain stimulation on visual processing and memory encoding is influenced by pain-related fear JF - NeuroImage N2 - 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. Y1 - 2016 U6 - https://doi.org/10.1016/j.neuroimage.2016.03.026 SN - 1053-8119 VL - 134 SP - 386 EP - 395 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bank, Bart L. van de A1 - Orzada, Stephan A1 - Smits, Frits A1 - Lagemaat, Miriam W. A1 - Rodgers, Christopher T. A1 - Bitz, Andreas A1 - Scheenen, Tom W. J. T1 - Optimized (31) P MRS in the human brain at 7 T with a dedicated RF coil setup JF - NMR in Biomedicine Y1 - 2015 U6 - https://doi.org/10.1002/nbm.3422 SN - 1099-1492 VL - 28 IS - 11 SP - 1570 EP - 1578 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Noureddine, Yacine A1 - Bitz, Andreas A1 - Ladd, Mark E. A1 - Thürling, Markus A1 - Ladd, Susanne C. A1 - Schaefers, Gregor A1 - Kraff, Oliver T1 - Experience with magnetic resonance imaging of human subjects with passive implants and tattoos at 7 T: a retrospective study JF - Magnetic Resonance Materials in Physics, Biology and Medicine Y1 - 2015 U6 - https://doi.org/10.1007/s10334-015-0499-y SN - 1352-8661 VL - 28 IS - 6 SP - 577 EP - 590 PB - Springer CY - Berlin ER - TY - JOUR A1 - Lagemaat, Miriam W. A1 - Breukels, Vincent A1 - Vos, Eline K. A1 - B., Adam A1 - Uden, Mark J. van A1 - Orzada, Stephan A1 - Bitz, Andreas A1 - Maas, Marnix C. A1 - Scheenen, Tom W. J. T1 - ¹H MR spectroscopic imaging of the prostate at 7T using spectral-spatial pulses JF - Magnetic Resonance in Medicine N2 - Purpose To assess the feasibility of prostate ¹H MR spectroscopic imaging (MRSI) using low-power spectral-spatial (SPSP) pulses at 7T, exploiting accurate spectral selection and spatial selectivity simultaneously. Methods A double spin-echo sequence was equipped with SPSP refocusing pulses with a spectral selectivity of 1 ppm. Three-dimensional prostate ¹H-MRSI at 7T was performed with the SPSP-MRSI sequence using an 8-channel transmit array coil and an endorectal receive coil in three patients with prostate cancer and in one healthy subject. No additional water or lipid suppression pulses were used. Results Prostate ¹H-MRSI could be obtained well within specific absorption rate (SAR) limits in a clinically feasible time (10 min). Next to the common citrate signals, the prostate spectra exhibited high spermine signals concealing creatine and sometimes also choline. Residual lipid signals were observed at the edges of the prostate because of limitations in spectral and spatial selectivity. Conclusion It is possible to perform prostate ¹H-MRSI at 7T with a SPSP-MRSI sequence while using separate transmit and receive coils. This low-SAR MRSI concept provides the opportunity to increase spatial resolution of MRSI within reasonable scan times. Y1 - 2016 U6 - https://doi.org/10.1002/mrm.25569 SN - 1522-2594 VL - 75 IS - 3 SP - 933 EP - 945 PB - International Society for Magnetic Resonance in Medicine ER - TY - JOUR A1 - Vos, E. K. A1 - Lagemaat, M. W. A1 - Barentsz, J. O. A1 - Fütterer, J. J. A1 - Zamecnik, P. A1 - Roozen, H. A1 - Orzada, S. A1 - Bitz, Andreas A1 - Maas, M. C. A1 - Scheenen, T. W. J. T1 - Image quality and cancer visibility of T2-weighted Magnetic Resonance Imaging of the prostate at 7 Tesla JF - European Radiology N2 - 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. Y1 - 2014 U6 - https://doi.org/10.1007/s00330-014-3234-6 SN - 1432-1084 VL - 24 IS - 8 SP - 1950 EP - 1958 PB - Springer CY - Cham ER - TY - JOUR A1 - Lagemaat, Miriam W. A1 - Maas, Marnix C. A1 - Vos, Eline K. A1 - Bitz, Andreas A1 - Orzada, Stephan A1 - Weiland, Elisabeth A1 - Uden, Mark J. van A1 - Kobus, Thiele A1 - Heerschap, Arend A1 - Scheenen, Tom W. J. T1 - (31) P MR spectroscopic imaging of the human prostate at 7 T: T1 relaxation times, Nuclear Overhauser Effect, and spectral characterization JF - Magnetic Resonance in Medicine Y1 - 2015 U6 - https://doi.org/10.1002/mrm.25209 SN - 1522-2594 VL - 73 IS - 3 SP - 909 EP - 920 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Theysohn, Jens M. A1 - Kraff, Oliver A1 - Eilers, Kristina A1 - Andrade, Dorian A1 - Gerwig, Marcus A1 - Timmann, Dagmar A1 - Schmitt, Franz A1 - Ladd, Mark E. A1 - Ladd, Susanne C. A1 - Bitz, Andreas T1 - Vestibular effects of a 7 Tesla MRI examination compared to 1.5 T and 0 T in healthy volunteers JF - PLoS one N2 - 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. Y1 - 2014 U6 - https://doi.org/10.1371/journal.pone.0092104 SN - 1932-6203 VL - 9 IS - 3 PB - PLOS CY - San Francisco ER - TY - JOUR A1 - Kraff, Oliver A1 - Bitz, Andreas A1 - Breyer, Tobias A1 - Kruszona, Stefan A1 - Maderwald, Stefan A1 - Brote, Irina A1 - Gizewski, Elke R. A1 - Ladd, Mark E. A1 - Quick, Harald H. T1 - A transmit/receive radiofrequency array for imaging the carotid arteries at 7 Tesla: coil design and first in vivo results JF - Investigative Radiology N2 - 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. Y1 - 2011 U6 - https://doi.org/10.1097/RLI.0b013e318206cee4 SN - 1536-0210 VL - 46 IS - 4 SP - 246 EP - 254 PB - Wolters Kluwer CY - Köln ER - TY - JOUR A1 - El Quardi, A. A1 - Streckert, J. A1 - Bitz, Andreas A1 - Münkner, S. A1 - Engel, J. A1 - Hansen, V. T1 - New fin-line devices for radiofrequency exposure of small biological samples in vitro allowing whole-cell patch clamp recordings JF - Bioelectromagnetics N2 - 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. Y1 - 2011 U6 - https://doi.org/10.1002/bem.20621 SN - 1521-186X VL - 32 IS - 2 SP - 102 EP - 112 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Schlamann, Marc A1 - Voigt, Melanie A. A1 - Maderwald, Stefan A1 - Bitz, Andreas A1 - Kraff, Oliver A1 - Ladd, Susanne C. A1 - Ladd, Mark E. A1 - Forsting, Michael A1 - Wilhelm, Hans T1 - Exposure to high-field MRI does not affect cognitive function JF - Journal of Magnetic Resonance Imaging N2 - 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. Y1 - 2010 U6 - https://doi.org/10.1002/jmri.22065 SN - 1522-2586 VL - 31 IS - 5 SP - 1061 EP - 1066 PB - Wiley-Liss CY - New York ER - TY - JOUR A1 - Bitz, Andreas A1 - Zhou, Yi A1 - El Quardi, Abdessamad A1 - Streckert, Joachim T1 - Occupational Exposure at Mobile Communication Base Station Antenna Sites JF - Frequenz Y1 - 2009 U6 - https://doi.org/10.1515/FREQ.2009.63.7-8.123 SN - 2191-6349 VL - 63 IS - 7-8 SP - 123 EP - 128 ER - TY - JOUR A1 - Schlamann, Marc A1 - Yoon, Min-Suk A1 - Maderwald, Stefan A1 - Pietrzyk, Thomas A1 - Bitz, Andreas A1 - Gerwig, Marcus A1 - Forsting, Michael A1 - Ladd, Susanne C. A1 - Ladd, Mark E. A1 - Kastrup, Oliver T1 - Short term effects of magnetic resonance imaging on excitability of the motor cortex at 1.5T and 7T JF - Academic Radiology N2 - 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. Y1 - 2010 U6 - https://doi.org/10.1016/j.acra.2009.10.004 SN - 1076-6332 VL - 17 IS - 3 SP - 277 EP - 281 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kraff, Oliver A1 - Bitz, Andreas A1 - Kruszona, Stefan A1 - Orzada, Stephan A1 - Schaefer, Lena C. A1 - Theysohn, Jens M. A1 - Maderwald, Stefan A1 - Ladd, Mark E. A1 - Quick, Harald H. T1 - An eight-channel phased array RF coil for spine MR imaging at 7 T JF - Investigative Radiology Y1 - 2009 U6 - https://doi.org/10.1097/RLI.0b013e3181b24ab7 SN - 1536-0210 VL - 44 IS - 11 SP - 734 EP - 740 PB - Lippincott Williams & Wilkins ER - TY - JOUR A1 - Schlamann, M. A1 - Yoon, M.-S. A1 - Maderwald, S. A1 - Pietrzyk, T. A1 - Bitz, Andreas A1 - Gerwig, M. A1 - Forsting, M. A1 - Ladd, S. C. A1 - Ladd, M. E. A1 - Kastrup, O. T1 - Auswirkungen der Magnetresonanztomografie auf die Elektrophysiologie des motorischen Kortex: eine Studie mit transkranieller Magnetstimulation T1 - Effects of MRI on the electrophysiology of the motor cortex: a TMS study JF - RöFo - Fortschritte auf dem Giebiet der Röntgenstrahlen und der bildgebenden Verfahren Y1 - 2009 U6 - https://doi.org/10.1055/s-0028-1109038 SN - 1438-9029 VL - 181 IS - 3 SP - 215 EP - 219 PB - Thieme CY - Stuttgart ER - TY - JOUR A1 - Klomp, D. W. J. A1 - Bitz, Andreas A1 - Heerschap, A. A1 - Scheenen, T. W. J. T1 - Proton spectroscopic imaging of the human prostate at 7 T JF - NMR in Biomedicine Y1 - 2009 U6 - https://doi.org/10.1002/nbm.1360 SN - 1099-1492 VL - 22 IS - 5 SP - 495 EP - 501 ER - TY - JOUR A1 - Lerchl, Alexander A1 - Krüger, Heike A1 - Niehaus, Michael A1 - Streckert, Joachim R. A1 - Bitz, Andreas A1 - Hansen, Volkert T1 - Effects of mobile phone electromagnetic fields at nonthermal SAR values on melatonin and body weight of Djungarian hamsters (Phodopus sungorus) JF - Journal of Pineal Research Y1 - 2008 U6 - https://doi.org/10.1111/j.1600-079X.2007.00522.x SN - 1600-079X VL - 44 IS - 3 SP - 267 EP - 272 ER - TY - JOUR A1 - Fiedler, Thomas M. A1 - Ladd, Mark E. A1 - Bitz, Andreas T1 - SAR Simulations & Safety JF - NeuroImage Y1 - 2017 U6 - https://doi.org/10.1016/j.neuroimage.2017.03.035 SN - 1053-8119 IS - Epub ahead of print PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Noureddine, Yacine A1 - Kraff, Oliver A1 - Ladd, Mark E. A1 - Wrede, Karsten H. A1 - Chen, Bixia A1 - Quick, Harald H. A1 - Schaefers, Gregor A1 - Bitz, Andreas T1 - In vitro and in silico assessment of RF-induced heating around intracranial aneurysm clips at 7 Tesla JF - Magnetic Resonance in Medicine Y1 - 2017 U6 - https://doi.org/10.1002/mrm.26650 SN - 1522-2594 IS - Early view PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Fiedler, Thomas M. A1 - Ladd, Mark E. A1 - Bitz, Andreas T1 - RF safety assessment of a bilateral four-channel transmit/receive 7 Tesla breast coil: SAR versus temperature limits JF - Medical Physics Y1 - 2017 U6 - https://doi.org/10.1002/mp.12034 N1 - This article is corrected by: Errata: Erratum: “RF safety assessment of a bilateral four-channel transmit/receive 7 Tesla breast coil: SAR versus tissue temperature limits” [Med. Phys. 44(1), 143–157 (2017)] Volume 44, Issue 2, 772 VL - 44 IS - 1 SP - 143 EP - 157 ER - TY - JOUR A1 - Lagemaat, Miriam W. A1 - Vos, Eline K. A1 - Maas, Marnix C. A1 - Bitz, Andreas A1 - Orzada, Stephan A1 - Uden, Mark J. van A1 - Kobus, Thiele A1 - Heerschap, Arend A1 - Scheenen, Tom W. J. T1 - Phosphorus magnetic resonance spectroscopic imaging at 7 T in patients with prostate cancer JF - Investigative Radiology N2 - 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. Y1 - 2014 U6 - https://doi.org/10.1097/RLI.0000000000000012 SN - 1536-0210 VL - 49 IS - 5 SP - 363 EP - 372 PB - Lippincott Williams & Wilkins CY - Philadelphia, Pa. ER - TY - JOUR A1 - Maas, Marnix C. A1 - Vos, Eline K. A1 - Lagemaat, Miriam W. A1 - Bitz, Andreas A1 - Orzada, Stephan A1 - Kobus, Thiele A1 - Kraff, Oliver A1 - Maderwald, Stefan A1 - Ladd, Mark E. A1 - Scheenen, Tom W. J. T1 - Feasibility of T₂-weighted turbo spin echo imaging of the human prostate at 7 tesla JF - Magnetic Resonance in Medicine N2 - 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. Y1 - 2014 U6 - https://doi.org/10.1002/mrm.24818 SN - 1522-2594 VL - 71 IS - 5 SP - 1711 EP - 1719 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Umutlu, Lale A1 - Kraff, Oliver A1 - Fischer, Anja A1 - Kinner, Sonja A1 - Maderwald, Stefan A1 - Nassenstein, Kai A1 - Nensa, Felix A1 - Grüneisen, Johannes A1 - Orzada, Stephan A1 - Bitz, Andreas A1 - Forsting, Michael A1 - Ladd, Mark E. A1 - Lauenstein, Thomas C. T1 - Seven-Tesla MRI of the female pelvis JF - European Radiology Y1 - 2013 U6 - https://doi.org/10.1007/s00330-013-2868-0 SN - 1432-1084 VL - 23 IS - 9 SP - 2364 EP - 2373 PB - Springer CY - Berlin ER - TY - JOUR A1 - Bitz, Andreas A1 - Felder, Jorg A1 - Wittig, Tilmann T1 - Designing MRI Coils with Aid of Simulation JF - Microwaves & RF Y1 - 2013 SN - 0745-2993 VL - 52 IS - 7 SP - 56 PB - Penton CY - Cleveland, Ohio ER - TY - JOUR A1 - Kraff, Oliver A1 - Wrede, Karsten H. A1 - Schoemberg, Tobias A1 - Dammann, Philipp A1 - Noureddine, Yacine A1 - Orzada, Stephan A1 - Ladd, Mark E. A1 - Bitz, Andreas T1 - MR safety assessment of potential RF heating from cranial fixation plates at 7 T JF - Medical Physics Y1 - 2013 U6 - https://doi.org/10.1118/1.4795347 SN - 2473-4209 VL - 40 IS - 4 SP - 042302-1 EP - 042302-10 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Umutlu, L. A1 - Maderwald, S. A1 - Kinner, S. A1 - Kraff, O. A1 - Bitz, Andreas A1 - Orzada, S. A1 - Johst, S. A1 - Wrede, K. A1 - Forsting, M. A1 - Ladd, M. E. A1 - Lauenstein, T. C. A1 - Quick, H. H. T1 - First-pass contrast-enhanced renal MRA at 7 Tesla: initial results JF - European Radiology Y1 - 2013 U6 - https://doi.org/10.1007/s00330-012-2666-0 SN - 1432-1084 VL - 23 IS - 4 SP - 1059 EP - 1066 PB - Springer CY - Berlin ER - TY - JOUR A1 - Umutlu, Lale A1 - Orzada, Stephan A1 - Kinner, Sonja A1 - Maderwald, Stefan A1 - Bronte, Irina A1 - Bitz, Andreas A1 - Kraff, Oliver A1 - Ladd, Susanne C. A1 - Antoch, Gerald A1 - Ladd, Mark E. A1 - Quick, Harald H. A1 - Lauenstein, Thomas C. T1 - Renal imaging at 7 Tesla: preliminary results JF - European Radiology N2 - 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. Y1 - 2011 SN - 1432-1084 VL - 21 IS - 4 SP - 841 EP - 849 PB - Springer CY - Berlin ER - TY - CHAP A1 - Alhwarin, Faraj A1 - Ferrein, Alexander A1 - Scholl, Ingrid T1 - CRVM: Circular Random Variable-based Matcher - A Novel Hashing Method for Fast NN Search in High-dimensional Spaces T2 - Proceedings of the 7th International Conference on Pattern Recognition Applications and Methods, ICPRAM 2018 Y1 - 2018 SN - 978-989-758-276-9 U6 - https://doi.org/10.5220/0006692802140221 SP - 214 EP - 221 ER - TY - CHAP A1 - Alhwarin, Faraj A1 - Schiffer, Stefan A1 - Ferrein, Alexander A1 - Scholl, Ingrid T1 - Optimized KinectFusion Algorithm for 3D Scanning Applications T2 - Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies - Volume 2: BIOIMAGING Y1 - 2018 SN - 978-989-758-278-3 U6 - https://doi.org/10.5220/0006594700500057 SP - 50 EP - 57 ER - TY - CHAP A1 - Ferrein, Alexander A1 - Schiffer, Stefan A1 - Kallweit, Stephan T1 - The ROSIN Education Concept - Fostering ROS Industrial-Related Robotics Education in Europe T2 - ROBOT 2017: Third Iberian Robotics Conference Y1 - 2018 SN - 978-3-319-70836-2 U6 - https://doi.org/10.1007/978-3-319-70836-2_31 N1 - Advances in Intelligent Systems and Computing, vol 694; (AISC, volume 694) SP - 370 EP - 381 PB - Springer CY - Cham ER - TY - CHAP A1 - Hofmann, Till A1 - Mataré, Victor A1 - Neumann, Tobias A1 - Schönitz, Sebastian A1 - Henke, Christoph A1 - Limpert, Nicolas A1 - Niemueller, Tim A1 - Ferrein, Alexander A1 - Jeschke, Sabina A1 - Lakemeyer, Gerhard T1 - Enhancing Software and Hardware Reliability for a Successful Participation in the RoboCup Logistics League 2017 Y1 - 2018 SN - 978-3-030-00308-1 U6 - https://doi.org/10.1007/978-3-030-00308-1_40 N1 - Lecture Notes in Computer Science, vol 11175 SP - 486 EP - 497 PB - Springer CY - Cham ER - TY - JOUR A1 - Schiffer, Stefan A1 - Ferrein, Alexander T1 - ERIKA—Early Robotics Introduction at Kindergarten Age JF - Multimodal Technologies Interact N2 - 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. Y1 - 2018 U6 - https://doi.org/10.3390/mti2040064 SN - 2414-4088 VL - 2 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Hüning, Felix A1 - Heuermann, Holger A1 - Wache, Franz-Josef T1 - Wireless CAN JF - Etz: Elektrotechnik & Automation N2 - In modernen elektronischen und mechatronischen Systemen, z. B. im industriellen oder automobil Bereich, kommunizieren eingebettete Steuergeräte und Sensoren vielfach über Bussysteme wie CAN oder LIN. Die Kommunikation findet in der Regel drahtgebunden statt, so dass der Kabelbaum für die Kommunikation sehr groß werden kann. Daher ist es naheliegend, Leitungen und dazugehörige Stecker, z. B. für nicht-sicherheitskritische Komfortsysteme, einzusparen und diese durch gerichtete Funkstrecken für kurze Entfernungen zu ersetzen. Somit könnten Komponenten wie ECUs oder Sensoren kabel- und steckerlos in ein Bussystem integriert werden. Zudem ist eine einfache galvanische und mechanische Trennung zu erreichen. Funkübertragung wird bei diesen Bussystemen derzeit nicht eingesetzt, da insbesondere die Echtzeitfähigkeit 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 Möglichkeit, dass sie ausspioniert werden können und so sensible Daten entwendet werden können. In dieser Arbeit wird eine alternative Realisierung zu den bestehenden Funksystemen vorgestellt, die aus wenigen Komponenten aufzubauen ist. Es ist eine protokolllose, echtzeitfähige Übertragung möglich und somit die transparente Integration in ein Bussystem wie CAN. Y1 - 2018 SN - 0170-1711 VL - 139 IS - 10 SP - 22 EP - 26 PB - VDE-Verlag CY - Wuppertal ER - TY - JOUR A1 - Hüning, Felix T1 - Nachrüstmöglichkeiten von Dieselfahrzeugen aus technischer Sicht JF - Zeitschrift für Verkehrsrecht : NZV Y1 - 2019 IS - 1 SP - 27 EP - 32 PB - C.H.Beck ER - TY - CHAP A1 - Essingholt, Felix A1 - Meyer, Frederic A1 - Kuhn, Peter A1 - Schmidt, Philip A1 - Benkner, Thorsten A1 - Grabmaier, Anton T1 - Non-invasive heart beat measurement using microwave resonators T2 - Proceedings, Vol. 2, Eurosensors 2018 Conference, Graz, Austria, 9–12 September 2018 Y1 - 2018 U6 - https://doi.org/10.3390/proceedings2131002 SN - 2504-3900 SP - 1002 PB - MDPI CY - Basel ER - TY - CHAP A1 - Heuermann, Holger A1 - Harzheim, Thomas A1 - Mühmel, Marc T1 - A maritime harmonic radar search and rescue system using passive and active tags T2 - 2020 17th European Radar Conference (EuRAD) N2 - 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. KW - Harmonic Radar KW - Rescue System KW - Frequency Doubler KW - Transponder KW - Tag Y1 - 2021 SN - 978-2-87487-061-3 U6 - https://doi.org/10.1109/EuRAD48048.2021.00030 N1 - 17th European Radar Conference, 13th - 15th January 2021, Utrecht, Netherlands SP - 73 EP - 76 PB - IEEE CY - New York, NY ER - TY - RPRT A1 - Jaekel, C. A1 - Klein, C. A1 - Barth, R. A1 - Roskos, H. A1 - Kyas, G. A1 - Schroeer, M. A1 - Hüning, Felix T1 - Dynamik von Nichtgleichgewichtszustaenden in Hochtemperatursupraleitern Abschlussbericht N2 - 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. T2 - Dynamics of non-equilibrium states in HTSC. Final report KW - Relaxation KW - Phonons KW - Calcium oxides KW - Electron-phonon coupling Y1 - 1996 N1 - Foerderkennzeichen BMBF 13N6288; TRN: DE97FD184 ER - TY - JOUR A1 - Roepke, Rene A1 - Köhler, Klemens A1 - Drury, Vincent A1 - Schroeder, Ulrik A1 - Wolf, Martin A1 - Meyer, Ulrike T1 - A pond full of phishing games - analysis of learning games for anti-phishing education JF - Model-driven Simulation and Training Environments for Cybersecurity. MSTEC 2020 N2 - 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. Y1 - 2020 SN - 978-3-030-62433-0 U6 - https://doi.org/10.1007/978-3-030-62433-0_32020 N1 - Lecture Notes in Computer Science, vol 12512 SP - 41 EP - 60 PB - Springer CY - Cham ER - TY - CHAP A1 - Hoegen, Anne von A1 - Doncker, Rik W. De A1 - Rütters, René T1 - Teaching Digital Control of Operational Amplifier Processes with a LabVIEW Interface and Embedded Hardware T2 - 2020 23rd International Conference on Electrical Machines and Systems (ICEMS) N2 - 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. Y1 - 2020 U6 - https://doi.org/10.23919/ICEMS50442.2020.9290928 N1 - 23rd International Conference on Electrical Machines and Systems (ICEMS), 24-27 November 2020, Hamamatsu, Japan SP - 1117 EP - 1122 PB - IEEE CY - New York, NY ER - TY - CHAP A1 - Schuba, Marko A1 - Höfken, Hans-Wilhelm T1 - Cybersicherheit in Produktion, Automotive und intelligenten Gebäuden T2 - IT-Sicherheit - Technologien und Best Practices für die Umsetzung im Unternehmen Y1 - 2022 SN - 978-3-446-47223-5 SN - 978-3-446-47347-8 U6 - https://doi.org/10.3139/9783446473478.012 SP - 193 EP - 218 PB - Carl Hanser Verlag CY - München ER - TY - CHAP A1 - Engländer, Jacques A1 - Kaminski, Lars A1 - Schuba, Marko T1 - Informationssicherheitsmanagement T2 - Digitalisierungs- und Informationsmanagement N2 - Daten und Informationen sind die wichtigsten Ressourcen vieler Unternehmen und müssen daher entsprechend geschützt werden. Getrieben durch die erhöhte Vernetzung von Informationstechnologie, die höhere Offenheit infolge datengetriebener Dienstleistungen und eine starke Zunahme an Datenquellen, rücken die Gefahren von Informationsdiebstahl, -manipulation und -verlust in den Fokus von produzierenden Unternehmen. Auf dem Weg zum lern- und wandlungsfähigen Unternehmen kann dies zu einem großen Hindernis werden, da einerseits zu hohe Sicherheitsanforderungen neue Entwicklungen beschränken, andererseits wegen des Mangels an ausreichenden Informationssicherheitskonzepten Unternehmen weniger Innovationen wagen. Deshalb bedarf es individuell angepasster Konzepte für die Bereiche IT-Security, IT-Safety und Datenschutz für vernetzte Produkte, Produktion und Arbeitsplätze. Bei der Entwicklung und Durchsetzung dieser Konzepte steht der Faktor Mensch im Zentrum aller Überlegungen. 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, über 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 für die Informationssicherheit festlegen können. KW - Informationssicherheitsmanagement KW - Cybersicherheit KW - Cybersecurity KW - Informationssicherheit KW - IT-Sicherheit Y1 - 2022 SN - 978-3-662-63757-9 SN - 978-3-662-63758-6 U6 - https://doi.org/10.1007/978-3-662-63758-6_15 SP - 373 EP - 398 PB - Springer Vieweg CY - Berlin ER - TY - CHAP A1 - Schuba, Marko A1 - Höfken, Hans-Wilhelm A1 - Linzbach, Sophie T1 - An ICS Honeynet for Detecting and Analyzing Cyberattacks in Industrial Plants T2 - 2021 International Conference on Electrical, Computer and Energy Technologies (ICECET) N2 - 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 KW - Conpot KW - honeypot KW - honeynet KW - ICS KW - cybersecurity Y1 - 2022 SN - 978-1-6654-4231-2 SN - 978-1-6654-4232-9 U6 - https://doi.org/10.1109/ICECET52533.2021.9698746 N1 - 2021 International Conference on Electrical, Computer and Energy Technologies (ICECET). 09-10 December 2021. Cape Town, South Africa. PB - IEEE ER - TY - CHAP A1 - Christian, Esser A1 - Montag, Tim A1 - Schuba, Marko A1 - Allhof, Manuel T1 - Future critical infrastructure and security - cyberattacks on charging stations T2 - 31st International Electric Vehicle Symposium & Exhibition and International Electric Vehicle Technology Conference (EVS31 & EVTeC 2018) Y1 - 2018 SN - 978-1-5108-9157-9 SP - 665 EP - 671 PB - Society of Automotive Engineers of Japan (JSAE) CY - Tokyo ER - TY - JOUR A1 - Heuermann, Holger A1 - Emmrich, Thomas A1 - Bongartz, Simon T1 - Microwave spark plug to support ignitions with high compression ratios JF - IEEE Transactions on Plasma Science N2 - 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◦. KW - Automotive application KW - ignition KW - microplasma KW - microwave (MW) plasma KW - plasma jet Y1 - 2022 U6 - https://doi.org/10.1109/TPS.2022.3183690 SN - 1939-9375 IS - Early Access SP - 1 EP - 6 PB - IEEE ER - TY - CHAP A1 - Nees, Franz A1 - Stengel, Ingo A1 - Meister, Vera G. A1 - Barton, Thomas A1 - Herrmann, Frank A1 - Müller, Christian A1 - Wolf, Martin T1 - 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 Müller, Martin R. Wolf N2 - Tagungsbeiträge aus den Bereichen KI, Prozessorganisation und Plattformen für Geschäftsprozesse, Sicherheit und Datenschutz sowie Prototypen und Modelle. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-13840 SN - 978-3-944330-66-2 N1 - 33. AKWI-Jahrestagung am 14.09.2020, ausgerichtet von der Hochschule Karlsruhe - Wirtschaft und Technik PB - mana-Buch CY - Heide ER - TY - CHAP A1 - Wolf, Martin A1 - Barton, Thomas A1 - Herrmann, Frank A1 - Meister, Vera G. A1 - Müller, Christian A1 - Seel, Christian T1 - Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung vom 15.09.2019 bis 18.09.2019 an der Fachhochschule für Angewandte Wissenschaften Aachen / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian Müller, Christian Seel N2 - Tagungsbeiträge aus den Bereichen Projektmanagement, Didaktik in der Wirtschaftsinformatik, IT-Sicherheit, Anwendungsfälle, Reifegradmodelle, Plattformen für Geschäftsprozesse und Prototypen. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-13026 SN - 978-3-944330-62-4 PB - mana-Buch CY - Heide ER - TY - CHAP A1 - Moll, Florian A1 - Köhler, Klemens A1 - Wolf, Martin T1 - Konzeption von IT-Sicherheitslösungen unter ethischen Gesichtspunkten am Beispiel einer Monitoring-App für mobile Endgeräte T2 - Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung N2 - Die steigende Popularität von mobilen Endgeräten im privaten und geschäftlichen Umfeld geht mit einem Anstieg an Sicherheitslücken und somit potentiellen Angriffsflächen einher. Als ein Element der technischen und organisatorischen Maßnahmen zum Schutz eines Netzwerkes können Monitoring-Apps dienen, die unerwünschtes Verhalten und Angriffe erkennen. Die automatisierte Überwachung von Endgeräten ist jedoch rechtlich und ethisch komplex. Dies in Kombination mit einer hohen Sensibilität der Nutzer und Nutzerinnen dieser Geräte in Bezug auf Privatsphäre, kann zu einer geringen Akzeptanz und Compliance führen. Eine datenschutzrechtlich und ethisch einwandfreie Konzeption solcher Apps bereits im Designprozess führt zu höherer Akzeptanz und verbessert so die Effizienz. Diese Analyse beschreibt Möglichkeiten zur Umsetzung. Y1 - 2019 SN - 978-3-944330-62-4 SP - 61 EP - 72 PB - mana-Buch CY - Heide ER - TY - CHAP A1 - Becker, Willi A1 - Wolf, Martin T1 - Entwicklung eines Einführungskonzepts für IT-Service-Management in KMU T2 - Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian Müller, Christian Seel N2 - Obwohl es eine Vielzahl von Einführungskonzepten für ITSM gibt, hat sich bisher keines dieser Konzepte auf breiter Linie durchgesetzt. Das gilt in erhöhtem Maße für ITSM-Einführungskonzepte für KMU, wohl nicht zuletzt aufgrund der Tatsache, dass der Mehrwert von ITSM für KMU aufgrund der geringeren Größe der IT-Organisationen nur entsprechend schwieriger generiert werden kann. Mit diesem Beitrag wird ein Einführungskonzept für ITSM in KMU systematisch hergeleitet. Dafür wurden zunächst 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 Einführungskonzept abgeleitet werden, welches insbesondere die positiven Effekte unterstützt bzw. verstärkt. Y1 - 2019 SN - 978-3-944330-62-4 SP - 129 EP - 137 PB - mana-Buch CY - Heide ER - TY - CHAP A1 - König, Johannes Alexander A1 - Kaiser, Steffen A1 - Wolf, Martin T1 - Entwicklung und Evaluierung eines Regeleditors für die grafische Erstellung von „Smart Living Environment“-Services T2 - Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian Müller, Christian Seel N2 - In diesem Paper wird die Entwicklung und Evaluation eines grafischen Regeleditors für das Erstellen von „Smart Living Environments“-Services vorgestellt. Dafür werden zunächst die Deduktion und Implementierung des grafischen Regeleditors erläutert. Anschließend wird eine Probandenstudie vorgestellt, in welcher der Mehrwert bezogen auf die Aspekte Zeit, Fehleranfälligkeit und Gebrauchstauglichkeit festgestellt wird. Y1 - 2019 SN - 978-3-944330-62-4 SP - 234 EP - 243 PB - mana-Buch CY - Heide ER -