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- 2019
- low-temperature electronics
- class AB operation
- optimization of analog electronic circuit
- operational amplifier
- LTspice environment
- buffer amplifier
- junction field-effect transistors
- Electronic Science and Technology
- Don State Technical University
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[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Maximum efficiency analysis in wireless power transfer
摘要： The optimum design of loosely coupled transformer is the key technique in the wireless power transfer system (WPT). An improved magnetic model based on partial element equivalent circuit (PEEC) method is proposed in this paper. All parts of magnetic flux are divided into four categories: 1) flyback to topology; 2) resonant to topology; 3) quasi-resonant to topology; and 4) self-resonant to topology. As becomes clear from previous discussion, the converter topology used must be able to tolerate the minimum copper loss and minimum number of turns in given power transformer capability. In this method, the preferred parameters are coil shape and dimension, operating frequency, and coupling coefficient. The validity of the optimization algorithm is verified by experimental results.
关键词： reluctance model,parameter optimization,partial element equivalent circuit method,wireless power transfer,Prime-Mal
更新于2025-09-23 15:22:29
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[IEEE 2017 International Conference on Computational Science and Computational Intelligence (CSCI) - Las Vegas, NV, USA (2017.12.14-2017.12.16)] 2017 International Conference on Computational Science and Computational Intelligence (CSCI) - Estimation of Illumination Map from Dermoscopy Images for Extracting Differential Structures Using Gabor Local Mesh Patterns
摘要： Melanoma is the most deadly form of skin cancer and its incidence rate is significantly increasing. The design of an assisted diagnosis system for the detection of melanoma is a challenging task involving various steps related to computer vision. Researchers have concluded that the accurate identification of melanoma requires robust preprocessing steps on dermoscopy images including hair removal, illumination correction etc., that can help in a better detection of melanoma. In this paper, we propose a novel illumination correction algorithm followed by robust feature extraction from dermoscopy images, leading to a better identification of cancer. Illumination correction is based on statistical estimation of illumination content in the images, followed by the extraction of differential structures using a combination of Gabor filtering followed by extracting local mesh patterns, which exhibit physiological significance based on various clinical rules for detecting melanoma. Our experiments show that the proposed technique outperforms all the other methods that have been considered in this paper.
关键词： Texture analysis,Optimization,Pattern recognition,Gabor filters,Melanoma
更新于2025-09-23 15:22:29
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[IEEE 2018 Digital Image Computing: Techniques and Applications (DICTA) - Canberra, Australia (2018.12.10-2018.12.13)] 2018 Digital Image Computing: Techniques and Applications (DICTA) - Inter-Subject Image Registration of Clinical Neck MRI Volumes using Discrete Periodic Spline Wavelet and Free form Deformation
摘要： This paper presents a framework for inter-patient image registration which uses a multi-thresholds, multi-similarity measures and multi-transformations based on compactly supported spline and discrete periodic spline wavelets (DPSWs) using the Gauss-Newton gradient descent (GNGD) and gradient descent (GD) optimization methods. Our primary intellectual contribution is incorporating DPSWs in the transformation while another includes fusing out-of-range concept in a surface matching technique which is implemented by a multi-transformations and multi-similarity measures. In particular, as a true deformation cannot be achieved by single combination of transformation, similarity measure (SM) and optimization of a registration process, a moving image is required to be brought within the range of a registration. On the other hand, the surface matching technique involves an edge position difference (EPD) SM in which coarse to fine surfaces are matched using multiple thresholds with a spline-based free from deformation (FFD) method. The registration experiments were performed on 3D clinical neck magnetic resonance (MR) images, with the results showing that our proposed method provides good accuracy and robustness.
关键词： Image registration,edge position difference,multi-resolution,inter-subject registration,optimization,discrete periodic spline wavelet
更新于2025-09-23 15:22:29
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[IEEE ICASSP 2018 - 2018 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) - Calgary, AB (2018.4.15-2018.4.20)] 2018 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) - A New Proximal Method for Joint Image Restoration and Edge Detection with the Mumford-Shah Model
摘要： In this paper, we propose an adaptation of the PAM algorithm to the minimization of a nonconvex functional designed for joint image denoising and contour detection. This new functional is based on the Ambrosio–Tortorelli approximation of the well-known Mumford–Shah functional. We motivate the proposed approximation, offering flexibility in the choice of the possibly non-smooth penalization, and we derive closed form expression for the proximal steps involved in the algorithm. We focus our attention on two types of penalization: ?1-norm and a proposed quadratic-?1 function. Numerical experiments show that the proposed method is able to detect sharp contours and to reconstruct piecewise smooth approximations with low computational cost and convergence guarantees. We also compare the results with state-of-the-art relaxations of the Mumford–Shah functional and a recent discrete formulation of the Ambrosio–Tortorelli functional.
关键词： Ambrosio–Tortorelli,non-smooth optimization,Segmentation,proximal algorithm,restoration
更新于2025-09-23 15:22:29
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Metric Learning for Patch-Based 3-D Image Registration
摘要： Patch-based image registration is a challenging problem in visual geometry, the crucial component of which is the selection of an appropriate similarity measure. The similarity measure participates in the objective calculation of the pose optimization, which determines the optimization convergence performance. In this paper, we propose learning a similarity metric of patches from reference and target images such that the pairwise patches with a small projection error receive high similarity scores. To achieve this objective, we designed and trained the classification, regression, and rank networks separately based on self-collected data sets. The network can directly output the projection error according to the patches, which is sensitive to the deviation of the pose transformation. We also designed evaluation criteria and validated the superior performance of the network's outputs compared with the performance of traditional methods, such as the sum of absolute difference and the sum of squared differences.
关键词： neural network,Image registration,pose optimization,metric learning
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO) - Reykjavik, Iceland (2018.8.8-2018.8.10)] 2018 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO) - Low-Cost Simulation-Driven Design of Broadband Rectifiers for Ambient RF Energy Harvesting
摘要： A steady growth of ambient RF energy density associated with a rapid increase of the number of broadcasting devices stimulates the research on broadband harvesting circuits. Such circuits can be used as energy sources for low-power sensors or Internet-of-Things devices. On the other hand, dedicated design techniques for rectifiers are lacking which results in poor performance of existing circuits. Also, their design cost is high because it involves hybrid electromagnetic (EM) and harmonic balance (HB) simulations. In this work, we propose a novel design procedure for low-cost design of broadband rectifiers. The core component of the approach is a novel equivalent-circuit-based low-fidelity model which does not involve harmonic balance (HB) simulations. The model consists of a matching circuit loaded with the RF-to-DC converter block represented using the S-parameter matrix. The latter is obtained from a single HB simulation of the converter circuit. Inaccuracy of the model is reduced using appropriate correction techniques. At the first stage of the design process, the proposed model is optimized for minimization of the in-band reflection. At the second stage, a hybrid HB-EM-based tuning oriented towards maximization of the structure efficiency is carried out. The proposed approach is demonstrated using a novel broadband rectifier operating within 0.5 GHz to 3.5 GHz band. Numerical cost of the method is 80% lower compared to direct EM-HB- based optimization of the rectifier circuit.
关键词： broadband rectifiers,constrained optimization,simulation-driven design,surrogate-based optimization,equivalent circuit model
更新于2025-09-23 15:21:21
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Material distributive topology design of UWB antenna using parallel computation of improved BPSO with FDTD
摘要： In this article, the material distributive topology-based design optimization of ultra-wide band (UWB) antenna is proposed by using improved binary particle swarm optimization (BPSO) with finite difference time domain (FDTD) method. In the improved BPSO implementation, the velocity of each particle is calculated based on complete set of bits of particle position vector. The V-shaped transfer function is employed to transform all real values of velocities to values in the interval [0,1]. The fitness function of all the particles in BPSO algorithm are computed parallely by using FDTD simulation. The usage of FDTD and the parallel computation helps in analyzing the broadband frequency characteristics of the antenna with a single simulation run. The return loss of the optimized UWB antenna obtained from FDTD, Computer Simulation Technology (CST) simulation and practical measurement are in good agreement and show good impedance matching.
关键词： UWB antenna,finite difference time domain (FDTD) method,topology optimization,Binary particle swarm optimization (BPSO)
更新于2025-09-23 15:21:21
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GWDWT-FCM: Change Detection in SAR Images Using Adaptive Discrete Wavelet Transform with Fuzzy C-Mean Clustering
摘要： Change detection in remote sensing images turns out to play a significant role for the preceding years. Change detection in synthetic aperture radar (SAR) images comprises certain complications owing to the reality that it endures from the existence of the speckle noise. Hence, to overcome this limitation, this paper intends to develop an improved model for detecting the changes in SAR image. In this model, two SAR images captivated at varied times will be considered as the input for the change detection process. Initially, discrete wavelet transform (DWT) is employed for image fusion, where the coefficients are optimized using improved grey wolf optimization (GWO) called adaptive GWO (AGWO) algorithm. Finally, the fused images after inverse transform are clustered using fuzzy C-means (FCM) clustering technique and a similarity measure is performed among the segmented image and ground truth image. With the use of all these technologies, the proposed model is termed as adaptive grey wolf-based DWT with FCM (AGWDWT-FCM). The similarity measures analyze the relevant performance measures such as accuracy, specificity and F1 score. Moreover, the performance of the AGWDWT-FCM in change detection model is compared to other conventional models, and the improvement is noted.
关键词： Filter coefficient,Adaptive discrete wavelet transform,Grey wolf optimization,Synthetic aperture radar,Fuzzy C-means clustering
更新于2025-09-23 15:21:21
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Submodularity issues in value-of-information-based sensor placement
摘要： The value of information represents a rational metric for guiding the optimization of sensing efforts to support infrastructure system management under uncertainty. Unfortunately, this metric lacks the property of submodularity. Submodularity can be intuitively understood as a diminishing returns property, whereby the incremental benefit of a specific measurement is higher when the set of other available measures is smaller. Metrics which exhibit this property can be optimized using efficient greedy approaches, with certain guarantees on the near-optimality of the results. In this paper, we examine the issue of submodularity related to the optimization of sensor monitoring schemes using the value of information metric. We illustrate how greedy optimization approaches using value of information can lead to sub-optimal solutions for sensing in certain situations. We also examine how one potential heuristic approach involving a submodular surrogate metric (e.g. the conditional entropy) might be used to avoid some of these shortcomings.
关键词： Entropy,Value of Information,Optimization,Submodularity
更新于2025-09-23 15:21:21
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Coulomb interaction-induced jitter amplification in RF-compressed high-brightness electron source ultrafast electron diffraction
摘要： We have theoretically and experimentally demonstrated an RF compression-based jitter-amplification effect in high-brightness electron source ultrafast electron diffraction (UED), which degrades the temporal resolution significantly. A detailed analysis and simulations reveal the crucial role of the longitudinal and transverse Coulomb interaction for this jitter-amplification effect, which accord very well with experimental results. An optimized compact UED structure for full compression has been proposed, which can suppress the jitter by half and improve the temporal resolution to sub-100 fs. This Coulomb interaction-induced jitter amplification exists in nearly the whole ultrafast physics field where laser-electron synchronization is required. Moreover, it cannot be suppressed completely. The quantified explanation for the mechanism and optimization provides important guidance for photocathode accelerators and other compression-based ultrashort electron pulse generation and precise control.
关键词： system optimization,jitter amplification,RF compression,high-brightness electron source,ultrafast electron diffraction,Coulomb interaction
更新于2025-09-23 15:21:21