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12th IEEE Energy Conversion Congress and Exposition-Asia (ECCE-Asia)

作者： Zhan, Cao Zhu, Lingyu Zhang, Yaxin Ji, Shengchang Zhang, Jian Yu, Chaoyun Xi An Jiao Tong Univ State Key Lab Elect Insulat & Power Equipment Xian Peoples R China China Southern Power Grid Technol Co LTD Guangzhou Peoples R China

ISBN: (纸本)9781728163444

Thermal management and condition monitoring of power converters demand the accurate estimation of the junction temperature of insulated-gate bipolar transistor (IGBT). With existing iteration methods, the junction temperature is fed forward to calculate the power loss and derive the junction temperature of the next cycle, causing the problem of accumulated calculation error. This letter proposes a novel iterative algorithm to improve the calculation accuracy. Unlike the conventional solutions, utilizing the junction temperature of the previous moment to calculate the power losses, the proposed iteration method uses junction temperature and power losses of the same moment to tackle the accumulated error problem. Since the iterative equation has unique solution, the convergence value is the actual junction temperature and power losses. The initial power losses has no influence on the result, so it is not necessary to obtain the accurate power loss for the estimation of junction temperature. Power cycling experiment is performed to verify the advantages of the novel iterative algorithm. The novel method solves the accumulated error compared to the traditional method. The accuracy of the novel method is also verified by the result of 100mA current test during power cycling.

关键词： IGBT junction temperature iterative algorithm power loss power cycling

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Optimizing Information Transfer Through Chemical Channels in Molecular Communication

Optimizing Information Transfer Through Chemical Channels in...

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IEEE Global Communications Conference (GLOBECOM)

作者： Ratti, Francesca Harper, Colton Magarini, Maurizio Pierobon, Massimiliano Politecn Milan Dipartimento Elettron Informaz & Bioingn I-120133 Milan Italy Univ Nebraska Dept Comp Sci & Engn Lincoln NE 68588 USA

ISBN: (纸本)9781728181042

The optimization of information transfer through molecule diffusion and chemical reactions is one of the leading research directions in Molecular Communication (MC) theory. The highly nonlinear nature of the processes underlying these channels poses challenges in adopting analytical approaches for their information-theoretic modeling and analysis. In this paper, a novel iterative methodology is proposed to numerically estimate achievable information rates. Based on the Nelder-Mead optimization, this methodology does not necessitate analytical formulations of MC components and their stochastic behavior, and, when applied to well-known scenarios, it demonstrates consistent results with theoretical bounds and superior performance to prior literature. A numerical example that abstracts communications between genetically engineered cells via simulation is presented and discussed in light of possible future applications to support the design and engineering of realistic MC systems.

关键词： Molecular Communication Chemical Reaction Channel Diffusion Channel iterative algorithm Mutual Information Achievable Information Rate

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EMPIRICALLY ACCELERATING SCALED GRADIENT PROJECTION USING DEEP NEURAL NETWORK FOR INVERSE PROBLEMS IN IMAGE PROCESSING

EMPIRICALLY ACCELERATING SCALED GRADIENT PROJECTION USING DE...

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IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

作者： Lee, Byung Hyun Chun, Se Young UNIST Grad Sch AI Seoul South Korea Seoul Natl Univ INMC Dept ECE Seoul South Korea

ISBN: (纸本)9781728176055

Recently, deep neural networks (DNNs) have shown advantages in accelerating optimization algorithms. One approach is to unfold finite number of iterations of conventional optimization algorithms and to learn parameters in the algorithms. However, these are forward methods and are indeed neither iterative nor convergent. Here, we present a novel DNN-based convergent iterative algorithm that accelerates conventional optimization algorithms. We train a DNN to yield parameters in scaled gradient projection method. So far, these parameters have been chosen heuristically, but have shown to be crucial for good empirical performance. In simulation results, the proposed method significantly improves the empirical convergence rate over conventional optimization methods for various large-scale inverse problems in image processing.

关键词： scaled gradient projection deep neural network iterative algorithm convergence

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Investigation of an iterative Method for Finding of Currents, Voltages and Termination Impedances of PCB Traces Based on Phase-less Near-field Data

Investigation of an Iterative Method for Finding of Currents...

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IEEE International Joint Symposium on Electromagnetic Compatibility (EMC), Signal and Power Integrity (SIPI) and EMC Europe

作者： Nowak, Robert Frei, Stephan TU Dortmund Univ On Board Syst Lab Dortmund Germany

ISBN: (纸本)9781665448888

The evaluation of near-field data can be an effective way to analyze EMI sources. In contrast to antenna measurements, near-field techniques can determine the emitted field without special requirements on the measurement environment. Moreover, critical sources can be found when current distributions can be identified. Therefore, current reconstruction methods for PCB traces were developed. With additional voltage information the termination impedances of the traces can be found. The known phase-less approaches suffers from different limitations, e.g., non-unique reconstruction results. In this paper, the necessary conditions for a unique reconstruction are discussed by investigating simulated phase-less near-field data. Based on these findings, measured near-field data of a PCB trace is evaluated, and the successful retrieval of the phase information is shown. Additionally, reconstructed voltage distributions are presented and compared to measurement data.

关键词： EMI near-field source reconstruction iterative algorithm phase retrieval current reconstruction method

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Numerical Evaluations for Multiplicative Algebraic Reconstruction Technique

Numerical Evaluations for Multiplicative Algebraic Reconstru...

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Biomedical Imaging and Sensing Conference

作者： Aoyagi, Tomohiro Ohtsubo, Kouichi Toyo Univ Fac Informat Sci & Arts 2100 Kujirai Kawagoe Shi Saitama 3508585 Japan

ISBN: (数字)9781510647206

ISBN: (纸本)9781510647206;9781510647190

Image reconstruction can be formulated by the Fredholm equation of the first kind The method of projections onto convex sets (POCS) is an iterative algorithm for solving the equation. Multiplicative algebraic reconstruction techniques (MART) is one of POCS for solving a system of simultaneous equation. By discretizing the image reconstruction problem, we applied the MART to the problems and evaluate the image quality in computer simulations. We also investigated the normalized mean square error of reconstructed images with respect to the variations of the number of detectors and views, the relaxation parameters.

关键词： image reconstruction MART POCS iterative algorithm tomography

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PRIVACY-ACCURACY TRADE-OFF OF INFERENCE AS SERVICE

PRIVACY-ACCURACY TRADE-OFF OF INFERENCE AS SERVICE

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IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

作者： Jin, Yulu Lai, Lifeng Univ Calif Davis Dept ECE Davis CA 95616 USA

ISBN: (纸本)9781728176055

In this paper, we propose a general framework to provide a desirable trade-off between inference accuracy and privacy protection in the inference as service scenario. Instead of sending data directly to the server, the user will preprocess the data through a privacy-preserving mapping, which will increase privacy protection but reduce inference accuracy. To properly address the trade-off between privacy protection and inference accuracy, we formulate an optimization problem to find the optimal privacy-preserving mapping. Even though the problem is non-convex in general, we characterize nice structures of the problem and develop an iterative algorithm to find the desired privacy-preserving mapping.

关键词： statistical inference privacy-preserving privacy-accuracy trade-off iterative algorithm

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Source Localization using TDOA and FDOA Measurements with Sensor Information Uncertainties 40

Source Localization using TDOA and FDOA Measurements with Se...

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40th Chinese Control Conference (CCC)

作者： Qu, Xiaomei Liu, Tao Southwest Minzu Univ Key Lab Comp Syst State Ethn Affairs Commiss Chengdu 610041 Sichuan Peoples R China

ISBN: (纸本)9789881563804

This paper explores the source localization problem using the time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements when sensor location information suffers from random uncertainties. The analysis of the Cramer-Rao lower bound (CRLB) illustrates that the sensor uncertainties can considerably deteriorate the localization accuracy, so we fully incorporate the sensor location information uncertainties into the problem formulation. An iterative source localization algorithm is proposed to recursively solve the formulated problem, where the sensor information uncertainties is incorporated in each iteration to improve the localization performance.

关键词： Source localization Sensor information uncertainties Cramer-Rao lower bound iterative algorithm

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iterative algorithms for the input and state recovery from the approximate inverse of strictly proper multivariable systems

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MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2018年 101卷 320-337页

作者： Chen, Liwen Xu, Qiang Lamar Univ Dan F Smith Dept Chem Engn POB 10053 Beaumont TX 77710 USA

This paper proposes new iterative algorithms for the unknown input and state recovery from the system outputs using an approximate inverse of the strictly proper linear time invariant (LTI) multivariable system. One of the unique advantages from previous system inverse algorithms is that the output differentiation is not required. The approximate system inverse is stable due to the systematic optimal design of a dummy feedthrough D matrix in the state-space model via the feedback stabilization. The optimal design procedure avoids trial and error to identify such a D matrix which saves tremendous amount of efforts. From the derived and proved convergence criteria, such an optimal D matrix also guarantees the convergence of algorithms. Illustrative examples show significant improvement of the reference input signal tracking by the algorithms and optimal D design over non-iterative counterparts on controllable or stabilizable LTI systems, respectively. Case studies of two Boeing-767 aircraft aerodynamic models further demonstrate the capability of the proposed methods. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： Approximate inverse Dummy D matrix iterative algorithm Stability Strictly proper

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Numerical and Experimental correlation on Electro-Hydro Dynamic system for Small Aircraft propulsion

Numerical and Experimental correlation on Electro-Hydro Dyna...

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AIAA Propulsion and Energy Forum / IEEE Electric Aircraft Technologies Symposium (EATS)

作者： Loehrmann, Antoine Rivenc, Jean Peres, Gilles Dufour, Guillaume Rogier, Francois Kourtzanidis, Konstantinos Airbus SAS Cent Res & Technol Div 18 Rue Marius Terce FR-31025 Toulouse France Off Natl Etud & Rech Aerosp French Aerosp Lab F-31000 Toulouse France Ctr Res & Technol Hellas Chem Proc & Energy Resources Inst Thessaloniki Greece Airbus Cent R&T Toulouse France

ISBN: (数字)9781624106118

ISBN: (纸本)9781624106118

In this study, we explored numerical and experimental tools, in order to study phenomena linked toEHD (Electro Hydro Dynamics), for the purpose of thrust applications for MAV (Micro Air Vehicles). A canonical case was considered, namely a wire of 50µm radius with a DC positive voltage, in front of a NACA 2412 profile at ground *** numerical approach consisted of self-consistently solving the ionization and drift phases, by combining a Poisson solver, for the electric field computation, and a plasma-fluid solver in an iterative process, until steady state was reached. The code COPAIER, developed by ONERA, was used for this *** discharge current was computed for several voltages between the electrodes, and the EHD force was injected into a CFD solver, in order to retrieve the ionic wind characteristics. An experimental study was also performed, by measuring the current-voltage characteristics. The latter was compared to numerical results. A deviation of less than 20% was obtained, as long as the discharge remained in the corona regime. Given the complexity of the studied phenomena, this result was better than our expectation. The corona to streamer transition was not studied, but could be taken into account by COPAIER. At last, the effect of pressure was experimentally studied, in the range between atmospheric pressure and 700mbars. The derating factor was evaluated between these two conditions: in our case, it was necessary, either to reduce the voltage by 10%, or to increase the electrodes gap by 30%.

关键词： Micro Air Vehicle NACA 2412 Aircraft Propulsion Electro Hydro Dynamics Numerical Modeling Poisson's Equation Finite Element Formulation Velocity Profiles Dielectric Barrier Discharge iterative algorithm

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An iterative model-free feature screening procedure: Forward recursive selection

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KNOWLEDGE-BASED SYSTEMS 2022年 246卷

作者： Xia, Siwei Yang, Yuehan Civil Aviat Flight Univ China Sch Sci Deyang Peoples R China Cent Univ Finance & Econ Sch Stat & Math Beijing Peoples R China

Many researchers have studied the combinations of machine learning techniques and traditional statistical strategies, and proposed effective procedures for complicated data sets. Yet, there is still some lack of running time and prediction accuracy. In this paper, we propose an iterative feature screening procedure, named forward recursive selection. We combine the random forest and forward selection to address the model-based limitations and the related requirements. We also use the forward strategy with a limited number of iterations to improve the computational efficiency. To provide the theoretical guarantees of this method, we calculate functions of the permutation importance of this algorithm in different models and data with group structures. Numerical comparisons and empirical analysis support our results, and the proposed procedure works well. (c) 2022 Elsevier B.V. All rights reserved.

关键词： Random forest Forward selection iterative algorithm Statistical modeling

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