TY  - GEN
A1  - Wiegner, J.
A1  - Volker, H.
A1  - Mainz, F.
A1  - Backes, A.
A1  - Löken, M.
A1  - Hüning, Felix
T1  - Wiegand-Effect-Powered Wireless IT Sensor Node
N2  - 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.
Y1  - 2022
N1  - PSMA International Energy Harvesting Workshop ~ 5-7 April 2022, Raleigh, NC, USA
ER  - 
TY  - JOUR
A1  - Gaigall, Daniel
T1  - On the applicability of several tests to models with not identically distributed random effects
JF  - Statistics : A Journal of Theoretical and Applied Statistics
N2  - We consider Kolmogorov–Smirnov and Cramér–von-Mises type tests for testing central symmetry, exchangeability, and independence. In the standard case, the tests are intended for the application to independent and identically distributed data with unknown distribution. The tests are available for multivariate data and bootstrap procedures are suitable to obtain critical values. We discuss the applicability of the tests to random effects models, where the random effects are independent but not necessarily identically distributed and with possibly unknown distributions. Theoretical results show the adequacy of the tests in this situation. The quality of the tests in models with random effects is investigated by simulations. Empirical results obtained confirm the theoretical findings. A real data example illustrates the application.
KW  - central symmetry test
KW  - exchangeability test
KW  - independence test
KW  - random effects
KW  - not identically distributed
Y1  - 2023
SN  - 0323-3944
U6  - http://dx.doi.org/10.1080/02331888.2023.2193748
SN  - 1029-4910
VL  - 57
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - CHAP
A1  - Tran, Ngoc Trinh
A1  - Trinh, Tu Luc
A1  - Dao, Ngoc Tien
A1  - Giap, Van Tan
A1  - Truong, Manh Khuyen
A1  - Dinh, Thuy Ha
A1  - Staat, Manfred
T1  - Limit and shakedown analysis of structures under random strength
T2  - Proceedings of (NACOME2022) The 11th National Conference on Mechanics, Vol. 1. Solid Mechanics, Rock Mechanics, Artificial Intelligence, Teaching and Training, Hanoi, December 2-3, 2022
N2  - Direct methods comprising limit and shakedown analysis is a branch of computational mechanics. It plays a significant role in mechanical and civil engineering design. The concept of direct method aims to determinate the ultimate load bearing capacity of structures beyond the elastic range. For practical problems, the direct methods lead to nonlinear convex optimization problems with a large number of variables and onstraints. If strength and loading are random quantities, the problem of shakedown analysis is considered as stochastic programming. This paper presents a method so called chance constrained programming, an effective method of stochastic programming, to solve shakedown analysis problem under random condition of strength. In this our investigation, the loading is deterministic, the strength is distributed as normal or lognormal variables.
KW  - Reliability of structures
KW  - Stochastic programming
KW  - Chance constrained programming
KW  - Shakedown analysis
KW  - Limit analysis
Y1  - 2022
SN  - 978-604-357-084-7
SP  - 510
EP  - 518
PB  - Nha xuat ban Khoa hoc tu nhien va Cong nghe (Verlag Naturwissenschaft und Technik)
CY  - Hanoi
ER  - 
TY  - JOUR
A1  - Gaigall, Daniel
ED  - AitSahlia, Farid
T1  - Allocating and forecasting changes in risk
JF  - Journal of risk
N2  - We consider time-dependent portfolios and discuss the allocation of changes in the risk of a portfolio to changes in the portfolio’s components. For this purpose we adopt established allocation principles. We also use our approach to obtain forecasts for changes in the risk of the portfolio’s components. To put the approach into practice we present an implementation based on the output of a simulation. Allocation is illustrated with an example portfolio in the context of Solvency II. The quality of the forecasts is investigated with an empirical study.
KW  - portfolio risk
KW  - allocation
KW  - forecast
KW  - covariance principle
KW  - conditional expectation principle
Y1  - 2023
U6  - http://dx.doi.org/10.21314/JOR.2022.048
SN  - 1755-2842
SN  - 1465-1211
VL  - 25
IS  - 3
SP  - 1
EP  - 24
PB  - Infopro Digital Risk
CY  - London
ER  - 
TY  - JOUR
A1  - Wiegner, Jonas
A1  - Volker, Hanno
A1  - Mainz, Fabian
A1  - Backes, Andreas
A1  - Loeken, Michael
A1  - Hüning, Felix
T1  - Energy analysis of a wireless sensor node powered by a Wiegand sensor
JF  - Journal of Sensors and Sensor Systems (JSSS)
N2  - This article describes an Internet of things (IoT) sensing device with a wireless interface which is powered by the energy-harvesting method of the Wiegand effect. The Wiegand effect, in contrast to continuous sources like photovoltaic or thermal harvesters, provides small amounts of energy discontinuously in pulsed mode. To enable an energy-self-sufficient operation of the sensing device with this pulsed energy source, the output energy of the Wiegand generator is maximized. This energy is used to power up the system and to acquire and process data like position, temperature or other resistively measurable quantities as well as transmit these data via an ultra-low-power ultra-wideband (UWB) data transmitter. A proof-of-concept system was built to prove the feasibility of the approach. The energy consumption of the system during start-up was analysed, traced back in detail to the individual components, compared to the generated energy and processed to identify further optimization options. Based on the proof of concept, an application prototype was developed.
Y1  - 2023
U6  - http://dx.doi.org/10.5194/jsss-12-85-2023
SN  - 2194-878X
N1  - Corresponding author: Felix Hüning
VL  - 12
IS  - 1
SP  - 85
EP  - 92
PB  - Copernicus Publ.
CY  - Göttingen
ER  - 
TY  - CHAP
A1  - Thoma, Andreas
A1  - Stiemer, Luc
A1  - Braun, Carsten
A1  - Fisher, Alex
A1  - Gardi, Alessandro G.
T1  - Potential of hybrid neural network local path planner for small UAV in urban environments
T2  - AIAA SCITECH 2023 Forum
N2  - This work proposes a hybrid algorithm combining an Artificial Neural Network (ANN) with a conventional local path planner to navigate UAVs efficiently in various unknown urban environments. The proposed method of a Hybrid Artificial Neural Network Avoidance System is called HANNAS. The ANN analyses a video stream and classifies the current environment. This information about the current Environment is used to set several control parameters of a conventional local path planner, the 3DVFH*. The local path planner then plans the path toward a specific goal point based on distance data from a depth camera. We trained and tested a state-of-the-art image segmentation algorithm, PP-LiteSeg. The proposed HANNAS method reaches a failure probability of 17%, which is less than half the failure probability of the baseline and around half the failure probability of an improved, bio-inspired version of the 3DVFH*. The proposed HANNAS method does not show any disadvantages regarding flight time or flight distance.
Y1  - 2023
U6  - http://dx.doi.org/10.2514/6.2023-2359
N1  - AIAA SCITECH 2023 Forum, 23-27 January 2023, National Harbor, MD & Online
PB  - AIAA
ER  - 
TY  - JOUR
A1  - Dickhoff, Jens
A1  - Horikawa, Atsushi
A1  - Funke, Harald
T1  - Hydrogen Combustion - new DLE Combustor Addresses NOx Emissions and Flashback
JF  - Turbomachinery international : the global journal of energy equipment
Y1  - 2021
SN  - 2767-2328
SN  - 0149-4147
VL  - 62
IS  - 4
SP  - 26
EP  - 27
PB  - MJH Life Sciences
CY  - Cranbury
ER  - 
TY  - CHAP
A1  - Horikawa, Atsushi
A1  - Ashikaga, Mitsugu
A1  - Yamaguchi, Masato
A1  - Ogino, Tomoyuki
A1  - Aoki, Shigeki
A1  - Wirsum, Manfred
A1  - Funke, Harald
A1  - Kusterer, Karsten
T1  - Combined heat and power supply demonstration of Micro-Mix Hydrogen Combustion Applied to M1A-17 Gas Turbine
T2  - Proceedings of ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition (GT2022) (Volume 3A)
N2  - Kawasaki Heavy Industries, Ltd. (KHI), Aachen University of Applied Sciences, and B&B-AGEMA GmbH have investigated the potential of low NOx micro-mix (MMX) hydrogen combustion and its application to an industrial gas turbine combustor. Engine demonstration tests of a MMX combustor for the M1A-17 gas turbine with a co-generation system were conducted in the hydrogen-fueled power generation plant in Kobe City, Japan.
This paper presents the results of the commissioning test and the combined heat and power (CHP) supply demonstration. In the commissioning test, grid interconnection, loading tests and load cut-off tests were successfully conducted. All measurement results satisfied the Japanese environmental regulation values. Dust and soot as well as SOx were not detected. The NOx emissions were below 84 ppmv at 15 % O2. The noise level at the site boundary was below 60 dB. The vibration at the site boundary was below 45 dB.
During the combined heat and power supply demonstration, heat and power were supplied to neighboring public facilities with the MMX combustion technology and 100 % hydrogen fuel. The electric power output reached 1800 kW at which the NOx emissions were 72 ppmv at 15 % O2, and 60 %RH. Combustion instabilities were not observed. The gas turbine efficiency was improved by about 1 % compared to a non-premixed type combustor with water injection as NOx reduction method. During a total equivalent operation time of 1040 hours, all combustor parts, the M1A-17 gas turbine as such, and the co-generation system were without any issues.
KW  - industrial gas turbine
KW  - combustor development
KW  - fuels
KW  - hydrogen
KW  - emission
Y1  - 2022
SN  - 978-0-7918-8599-4
U6  - http://dx.doi.org/10.1115/GT2022-81620
N1  - ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition
June 13–17, 2022 Rotterdam, Netherlands
PB  - American Society of Mechanical Engineers
CY  - Fairfield
ER  - 
TY  - CHAP
A1  - Möhren, Felix
A1  - Bergmann, Ole
A1  - Janser, Frank
A1  - Braun, Carsten
T1  - On the determination of harmonic propeller loads
T2  - AIAA SCITECH 2023 Forum
N2  - Dynamic loads significantly impact the structural design of propeller blades due to fatigue and static strength. Since propellers are elastic structures, deformations and aerodynamic loads are coupled. In the past, propeller manufacturers established procedures to determine unsteady aerodynamic loads and the structural response with analytical steady-state calculations. According to the approach, aeroelastic coupling primarily consists of torsional deformations. They neglect bending deformations, deformation velocities, and inertia terms. This paper validates the assumptions above for a General Aviation propeller and a lift propeller for urban air mobility or large cargo drones. Fully coupled reduced-order simulations determine the dynamic loads in the time domain. A quasi-steady blade element momentum approach transfers loads to one-dimensional finite beam elements. The simulation results are in relatively good agreement with the analytical method for the General Aviation propeller but show increasing errors for the slender lift propeller. The analytical approach is modified to consider the induced velocities. Still, inertia and velocity proportional terms play a significant role for the lift propeller due to increased elasticity. The assumption that only torsional deformations significantly impact the dynamic loads of propellers is not valid. Adequate determination of dynamic loads of such designs requires coupled aeroelastic simulations or advanced analytical procedures.
Y1  - 2023
U6  - http://dx.doi.org/10.2514/6.2023-2404
N1  - AIAA SCITECH 2023 Forum, 23-27 January 2023, National Harbor, MD & Online
PB  - AIAA
ER  - 
TY  - CHAP
A1  - Hille, Sebastian
A1  - Stumpf, Eike
A1  - Mayntz, Joscha
A1  - Dahmann, Peter
T1  - Prediction of sound exposure caused by a landing motor glider with recuperating propellers
T2  - AIAA SCITECH 2023 Forum
N2  - This paper presents an approach to predicting the sound exposure on the ground caused by a landing aircraft with recuperating propellers. The noise source along the trajectory of a flight specified for a steeper approach is simulated based on measurements of sound power levels and additional parameters of a single propeller placed in a wind tunnel. To validate the measured data/measurement results, these simulations are also supported by overflight measurements of a test aircraft. It is shown that the simple source models of propellers do not provide fully satisfactory results since the sound levels are estimated too low. Nevertheless, with a further reference comparison, margins for an acceptable increase in the sound power level of the aircraft on its now steeper approach path could be estimated. Thus, in this case, a +7 dB increase in SWL would not increase the SEL compared to the conventional approach within only 2 km ahead of the airfield.
Y1  - 2023
U6  - http://dx.doi.org/10.2514/6.2023-0211
N1  - AIAA SCITECH 2023 Forum, 23-27 January 2023, National Harbor, MD & Online
PB  - AIAA
ER  -