TY - JOUR A1 - Fibich, Christian A1 - Schmitt, Patrick A1 - Höller, Roland A1 - Rössler, Peter T1 - Open-Source Ethernet MAC IP Cores for FPGAs: Overview and Evaluation JF - International Journal of Reconfigurable Computing KW - Ethernet KW - FPGA KW - Design Reuse KW - IP Core KW - Open Source Y1 - U6 - http://dx.doi.org/https://doi.org/10.1155/2023/9222318 VL - 2023 SP - Article ID 9222318 ER - TY - JOUR A1 - Himmelstoss, Felix T1 - Design of State-Space Controllers with the Help of Signal Flow Graphs Shown for a Buck Converter JF - WSEAS Transactions on Power Systems, Volume 21, 2022, pp. 421-429 KW - DC/DC converter KW - Buck converter KW - modelling KW - simulation KW - state space controller Y1 - U6 - http://dx.doi.org/10.37394/23202.2022.21.46 VL - Volume 21 SP - 421 EP - 429 ER - TY - JOUR A1 - Himmelstoss, Felix A1 - Votzi, Helmut T1 - Simple Chargers for a Small DC Micro-Grid for a Home Emergency Power System JF - Electricity KW - micro-grid KW - Buck converter KW - Boost converter KW - hysteresis control Y1 - U6 - http://dx.doi.org/https://doi.org/10.3390/electricity4030013 VL - 4 IS - 3 SP - 216 EP - 234 ER - TY - JOUR A1 - Himmelstoss, Felix T1 - Quasi Resonant Zero Current Switching Modified Boost Converter (QRZCSMBC) JF - WSEAS Transactions on Power Systems KW - DC/DC converter KW - modified boost converter KW - inrush current KW - zero current switching ZCS KW - simulation Y1 - U6 - http://dx.doi.org/10.37394/23201.2023.22.8 VL - Volume 22 SP - 55 EP - 62 ER - TY - JOUR A1 - Himmelstoss, Felix T1 - Third order converters with current output for driving LEDs JF - WSEAS Transactions on Power Systems KW - DC/DC converters KW - current output KW - limited duty cycle converter KW - simulation KW - modeling Y1 - U6 - http://dx.doi.org/10.37394/232016.2022.17.40 VL - Volume 17 SP - 402 EP - 409 ER - TY - JOUR A1 - Marc, Zobel A1 - Knapp, Bernhard A1 - Nateqi, Jama A1 - Martin, Alistair T1 - Correlating global trends in COVID-19 cases with online symptom checker self-assessments JF - PLOS ONE N2 - Background Online symptom checkers are digital health solutions that provide a differential diagnosis based on a user’s symptoms. During the coronavirus disease 2019 (COVID-19) pandemic, symptom checkers have become increasingly important due to physical distance constraints and reduced access to in-person medical consultations. Furthermore, various symptom checkers specialised in the assessment of COVID-19 infection have been produced. Objectives Assess the correlation between COVID-19 risk assessments from an online symptom checker and current trends in COVID-19 infections. Analyse whether those correlations are reflective of various country-wise quality of life measures. Lastly, determine whether the trends found in symptom checker assessments predict or lag relative to those of the COVID-19 infections. Materials and methods In this study, we compile the outcomes of COVID-19 risk assessments provided by the symptom checker Symptoma (www.symptoma.com) in 18 countries with suitably large user bases. We analyse this dataset’s spatial and temporal features compared to the number of newly confirmed COVID-19 cases published by the respective countries. Results We find an average correlation of 0.342 between the number of Symptoma users assessed to have a high risk of a COVID-19 infection and the official COVID-19 infection numbers. Further, we show a significant relationship between that correlation and the self-reported health of a country. Lastly, we find that the symptom checker is, on average, ahead (median +3 days) of the official infection numbers for most countries. Conclusion We show that online symptom checkers can capture the national-level trends in coronavirus infections. As such, they provide a valuable and unique information source in policymaking against pandemics, unrestricted by conventional resources. KW - Online symptom checkers KW - coronavirus disease Y1 - U6 - http://dx.doi.org/https://doi.org/10.1371/journal.pone.0281709 VL - 18 IS - 2 ER - TY - CHAP A1 - Himmelstoss, Felix A1 - Windisch, Michael T1 - A capacitor-free driving stage for light emitting diodes T2 - 21th International Conference on Renewable Energies and Power Quality (ICREPQ’23) Madrid (Spain), 24th to 26th May 2023 N2 - Electrolytic capacitors have the disadvantage of pronounced aging. Non-electrolytic capacitors are therefore used in applications where long-life is important. In this paper we present a driving stage for LEDs without any capacitive elements. The basic topology is a Buck converter with one coil, one active, and one passive switch. Instead of the output capacitor, series connections of one or more LEDs and an active switch are connected. An additional diode is connected between the output and the input to achieve a current path, when all LED- paths are off. A nonlinear hysteresis controller is used to achieve a robust control. A system with three switchable LED-strings is analyzed. Design hints are given and the function is proved with the help of LTSpice simulations. The system can be used for lighting purposes with the possibility to change the chrominance. The potentiality to transmit data is also treated. KW - DC-to-DC converter KW - stray inductance KW - recuperation KW - active snubber Y1 - U6 - http://dx.doi.org/10.24084/repqj21.278 VL - Vol. 21 SP - 220 EP - 225 ER - TY - CHAP A1 - Himmelstoss, Felix A1 - Windisch, Michael T1 - Tapped inductor Boost with exploitation of the stray energy T2 - Proceedings of 2022 IEEE 20th International Power Electronics and Motion Control Conference (PEMC 2022), Brasov, Rumania, Sep. 25-29 N2 - Tapped inductor DC-to-DC converters are interesting circuits, the winding ratio of the two windings mounted on the same core change the voltage transformation ratio compared to the untapped inductor. The tapped inductor converters are especially useful, when high or low voltage transformation ratios have to be realized. The disadvantage of this concept is that the coupling between the two windings is not total and can be described by the stray or leakage inductance. This stray inductance leads to a high overvoltage at the active switch, and therefore also across other elements of the converter. After a short summery of the ideal tapped Boost converter, the design of an RCD snubber which limits the overvoltage is explained. To improve the efficiency of the converter two active snubber networks are treated, which feed the energy stored in the snubber capacitor into the input source or into the output circuit. Simulations are used to prove these considerations. KW - DC/DC converter KW - stray inductance KW - recuperation KW - active snubber Y1 - U6 - http://dx.doi.org/10.1109/PEMC51159.2022.9962849 SP - 75 EP - 80 ER - TY - CHAP A1 - Himmelstoss, Felix A1 - Votzi, Helmut T1 - Two-Stage Step-up Converter with Different Voltage Transformation Ratios depending on the Duty Cycle T2 - 20th International Conference on Renewable Energies and Power Quality (ICREPQ’22) Vigo (Spain), 27th to 29th July 2022 N2 - A two-stage converter with high output voltage ratio and reduced current stress of the inductors and partly reduced voltage stress is discussed. The function is explained with the help of voltage and current diagrams. The voltage transformation ratio changes between a quadratic step-up for duty cycles lower 0.5 and a double Boost converter for duty cycles higher than 0.5. Dimensioning hints, the control law for feed-forward controls, the transient when the supply is turned on is discussed and some simulations are given. A comparison to other two-stage converters is also treated. KW - Quadratic boost KW - double boost converter KW - feed-forward control KW - start-up Y1 - U6 - http://dx.doi.org/10.24084/repqj20.218 VL - Vol. 20 SP - 66 ER - TY - CHAP A1 - Fibich, Christian A1 - Horauer, Martin A1 - Obermaisser, Roman T1 - Bitstream-Level Interconnect Fault Characterization for SRAM-based FPGAs T2 - Proceedings of the 2023 Design, Automation & Test in Europe Conference & Exhibition (DATE 2023), pp. 1-2, 16-18 April 2023, Antwerp, Belgium KW - FPGA KW - Fault Injection KW - Interconnect Fault Y1 - U6 - http://dx.doi.org/10.23919/DATE56975.2023.10136911 ER -