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Orthogonal Nelder-Mead moth flame method for parameters identification of photovoltaic modules
摘要： Defining the optimal parameters of the photovoltaic system (PV) models according to the actual real voltage and current data is a crucial process during designing, emulating, estimating, dominating, and optimizing photovoltaic systems. Therefore, it is necessary to effectively advance the optimal parameters of the models based on the proper optimization methods. For this purpose, this paper proposes an orthogonal moth flame optimization (MFO) with a local search for identifying parameters of photovoltaic cell models, which is named NMSOLMFO. The presented method is organized based on the principal exploratory and exploitative mechanisms of MFO. Also, its exploration and exploitation capability is strengthened by the orthogonal learning (OL) strategy and Nelder-Mead simplex (NMS) method, and this new scheme supports a more stable equilibrium between the central propensities. In the new MFO-based method, OL strategy can construct a healthier candidate location for the inferior agents, and then, it directs them to probe a reasonable prospective zone throughout a few rational trials. Besides, the NMS local search scheme can augment the accurateness of the global optimal solution by searching its neighborhood throughout the searching process, and the global optimum is taken as the initial point. In our study, first, the developed MFO-based approach is employed to tackle IEEE CEC 2014 benchmark cases with 30D to evaluate the effectiveness of the method in solving high dimensional and multimodal problems. Then, it is utilized to deal with parameters identification of single diode model (SDM), double diode model (DDM), and photovoltaic module model (PVM). The results and statistical studies indicate that NMSOLMFO can outperform the majority of other investigated methods concerning accuracy and convergence rapidity. The obtained results imply that the novel approach can provide a new practical tool for parameter definition in PV models, and it can be beneficial to upgrade the PV systems.
关键词： Parameter identification,Orthogonal learning,Simplex method,Moth flame optimization,Solar module
更新于2025-09-23 15:21:01
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Transiently changing shape of the photon number distribution in a quantum-dota??cavity system driven by chirped laser pulses
摘要： We have simulated the time evolution of the photon number distribution in a semiconductor quantum-dot–microcavity system driven by chirped laser pulses and compare with unchirped results. When phonon interactions with the dot are disregarded—thus corresponding to the limit of atomic cavity systems—chirped pulses generate photon number distributions that change their shape drastically in the course of time. Phonons have a strong and qualitative impact on the photon statistics. The asymmetry between phonon absorption and emission destroys the symmetry of the photon distributions obtained for positive and negative chirps. While for negative chirps transient distributions resembling thermal ones are observed, for positive chirps the photon number distribution still resembles its phonon-free counterpart but with overall smoother shapes. In sharp contrast, using unchirped pulses of the same pulse area and duration wave packets are found that move up and down the Jaynes-Cummings ladder with a bell shape that changes little in time. For shorter pulses and lower driving strength Rabi-like oscillations occur between low photon number states. For all considered excitation conditions transitions between sub- and super-Poissonian statistics are found at certain times. For resonant driving with low intensity the Mandel parameter oscillates and is mostly negative, which indicates a nonclassical state in the cavity ?eld. Finally, we show that it is possible that the Mandel parameter dynamically approaches zero and still the photon distribution exhibits two maxima and thus is far from being a Poissonian.
关键词： Mandel parameter,photon number distribution,chirped laser pulses,quantum-dot–cavity system,phonon interactions
更新于2025-09-23 15:21:01
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Modeling and parameters extraction of photovoltaic cell and modules using the genetic algorithms with lambert W-function as objective function
摘要： In this paper, a method based on genetic algorithms is proposed for improving the accuracy of solar cell parameters extracted using novel technique. We propose a computational based binary-coded genetic algorithm (GA) to extract the parameters (I0, Iph, n, Rs and Rsh) for a single diode model of solar cell from its current-voltage (I–V) characteristic. The algorithm was implemented using Matlab as a programming tool and validated by applying it to the I–V curve synthesized from the literature using reported values. The characterization, current-voltage data used was generated by simulating a one-diode solar cell model of speci?ed parameters. The new approach is based on formulating I–V equation of solar cell, with Lambert function, the parameter extraction as a search and optimization problem. Compared with other optimization techniques in literatures, the approach proposed for the determination of parameters are in good agreement.
关键词： Photovoltaic solar cell,genetic algorithm,optimization,parameter extraction,Lambert function
更新于2025-09-23 15:21:01
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Rapid and Low-Cost Detection of Thyroid Dysfunction Using Raman Spectroscopy and an Improved Support Vector Machine
摘要： This study presents a rapid and low-cost method to detect thyroid dysfunction using serum Raman spectroscopy combined with support vector machine (SVM). The serum samples taken from 34 thyroid dysfunction patients and 40 healthy volunteers were measured in this study. Tentative assignments of the Raman bands in the measured serum spectra suggested specific biomolecular changes between the groups. Principal component analysis (PCA) was used for feature extraction and reduced the dimension of high-dimension spectral data; then, SVM was employed to establish an effective discriminant model. To improve the efficiency and accuracy of the SVM discriminant model, we proposed artificial fish coupled with uniform design (AFUD) algorithm to optimize the SVM parameters. The average accuracy of 30 discriminant results reached 82.74%, and the average optimization time was 0.45 s. The results demonstrate that the serum Raman spectroscopy technique combined with the AFUD-SVM discriminant model has great potential for the detection of thyroid dysfunction. This technique could be used to develop a portable, rapid, and low-cost device for detecting thyroid function to meet the needs of individuals and communities.
关键词： Raman spectroscopy,support vector machine (SVM),optical diagnosis,thyroid dysfunction,parameter optimization
更新于2025-09-23 15:21:01
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Robust Radial Velocity Estimation Based on Joint-Pixel Normalized Sample Covariance Matrix and Shift Vector for Moving Targets
摘要： The clutter suppression and target radial velocity estimation are essential in the ground moving target indication processing with multichannel synthetic aperture radar (SAR) systems. In reality, the heterogeneous clutter, the image coregistration error, and channel mismatch will remarkably decline the estimation performance of the target radial velocity. To address these issues, a robust radial velocity estimation algorithm is proposed in this letter. Based on the joint-pixel signal model, the joint-pixel normalized sample covariance matrix (JPNSCM) is employed to mitigate the effect of heterogeneous clutter, and the shift vector determined by JPNSCM is used to obtain the actual target steering vector. Then, the adaptive matched ?ltering algorithm is adopted to estimate the target radial velocity. Compared with traditional estimation algorithms, the proposed method obtains better performance in both simulations and real SAR data experiments.
关键词： Ground moving target indication (GMTI),synthetic aperture radar (SAR),parameter estimation
更新于2025-09-23 15:21:01
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Multi-objective Parameter Auto-tuning for Tissue Image Segmentation Workflows
摘要： We propose a software platform that integrates methods and tools for multi-objective parameter auto-tuning in tissue image segmentation workflows. The goal of our work is to provide an approach for improving the accuracy of nucleus/cell segmentation pipelines by tuning their input parameters. The shape, size, and texture features of nuclei in tissue are important biomarkers for disease prognosis, and accurate computation of these features depends on accurate delineation of boundaries of nuclei. Input parameters in many nucleus segmentation workflows affect segmentation accuracy and have to be tuned for optimal performance. This is a time-consuming and computationally expensive process; automating this step facilitates more robust image segmentation workflows and enables more efficient application of image analysis in large image datasets. Our software platform adjusts the parameters of a nuclear segmentation algorithm to maximize the quality of image segmentation results while minimizing the execution time. It implements several optimization methods to search the parameter space efficiently. In addition, the methodology is developed to execute on high-performance computing systems to reduce the execution time of the parameter tuning phase. These capabilities are packaged in a Docker container for easy deployment and can be used through a friendly interface extension in 3D Slicer. Our results using three real-world image segmentation workflows demonstrate that the proposed solution is able to (1) search a small fraction (about 100 points) of the parameter space, which contains billions to trillions of points, and improve the quality of segmentation output by × 1.20, × 1.29, and × 1.29, on average; (2) decrease the execution time of a segmentation workflow by up to 11.79× while improving output quality; and (3) effectively use parallel systems to accelerate parameter tuning and segmentation phases.
关键词： Parameter auto-tuning,Cancer,Cell morphology,Computer-assisted image analysis,Digital pathology
更新于2025-09-23 15:21:01
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Nanosecond-pulsed laser welding of metallic glass
摘要： This study explores nanosecond-pulsed (ns-pulsed) laser welding on the metallic glass (MG) ribbons of four compositions: Fe78Si9B13, Zr65Cu15Ni10Al10, La55Ni20Al25 and Ce65Al10Cu20Co5. All MGs can be welded in the air by the ns-pulsed laser, and the crystallization of the welding joints can be avoided by proper control of the laser parameters. By varying the travel speed, pulse duration and repetition frequency, the critical crystallization time of MG can be quickly detected in a high-throughput way by ns-pulsed laser welding. At the optimal processing conditions, 70–90% of the tensile strength of the parent melt-spun ribbon can be preserved in the welded MG ribbons. The mechanical strength is well linked to the pro?le of the welding joint, which suggests a simple method to evaluate the welding quality. A welding parameter map has been established based on the experiments, and it is concluded that the laser power-density per sample thickness and the interaction time are the key factors that control the crystallization and strength of the welding joints. The map is valid for a broad range of MG compositions of all sample thickness, and thus the optimal processing conditions may be extended to all MGs with equivalent glass-forming ability.
关键词： Strength,Metallic glass,Thickness,Laser welding,Welding parameter map
更新于2025-09-23 15:19:57
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Equivalent Circuit Parameters of Hybrid Quantum-Dot Solar Cells
摘要： We experimentally investigate the equivalent circuit parameters of hybrid quantum-dot (QD) solar cells consisted of InAs/GaAs and GaSb/GaAs QDs. The hybrid QD solar cell samples are fabricated by stacking one pair and three pairs of InAs/GaAs and GaSb/GaAs QD layers. Four equivalent circuit models are applied to fit the experimentally obtained current-voltage characteristics of the investigated samples. The relevant circuit parameters are photocurrent, reverse saturation current, diode ideality factor, series resistance, and shunt resistance. The best fitted model of all samples contains both series and shunt resistances. According to the fitting result, the diode ideality factor of 2, which indicates the dominant recombination current, is always obtained. Comparing the extracted parameters from two single-pair hybrid QD solar cells, the effects of structural stacking sequence can be discussed in term of light absorption and carrier storage properties. We have found that an increase of stacking number from one pair to three pairs deteriorates the solar cell performance. This might be caused by an excessive total QD layer thickness or a presence of dislocation defects in that sample.
关键词： Parameter Extraction,Current-Voltage Characteristics,Solar Cell,Quantum Dot
更新于2025-09-23 15:19:57
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Asymmetric photoelectron emission from chiral molecules using a high repetition rate laser
摘要： In the chiro-optical phenomenon known as photoelectron circular dichroism, the angular distribution of electrons ionized from chiral molecules by circularly polarized light pulses has been found to be anti-symmetric with respect to the direction of the light propagation. To study this phenomenon, chiral molecules were multiphoton ionized with a femtosecond laser in our laboratory. Using a simple stereo-detection setup, direct measurements of the asymmetry for the exemplar aromatic chiral molecule 1-phenylethanol were made using 260 nm pulses produced at a rate of 1 MHz. It was found that the asymmetry had a linear dependence on Stokes’ S3 parameter indicating that the photoelectron circular dichroism is due to a single photon process from the excited state of the molecule. This is in contrast to previous and new results for camphor where a more complex dependence on S3 suggested that selective excitation of molecules with certain orientations was influential.
关键词： photoelectron circular dichroism,circularly polarized light,asymmetry,Stokes’ S3 parameter,chiral molecules
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Design and Fabrication of AlGaAs-based 1.8eV Schottky Solar Cell
摘要： Most sensitivity analysis studies of optimization algorithm control parameters are restricted to a single objective function evaluation (OFE) budget. This restriction is problematic because the optimality of control parameter values (CPVs) is dependent not only on the problem’s fitness landscape, but also on the OFE budget available to explore that landscape. Therefore, the OFE budget needs to be taken into consideration when performing control parameter tuning. This paper presents a new algorithm tuning multiobjective particle swarm optimization (tMOPSO) for tuning the CPVs of stochastic optimization algorithms under a range of OFE budget constraints. Specifically, for a given problem tMOPSO aims to determine multiple groups of CPVs, each of which results in optimal performance at a different OFE budget. To achieve this, the control parameter tuning problem is formulated as a multiobjective optimization problem. Additionally, tMOPSO uses a noise-handling strategy and CPV assessment procedure, which are specialized for tuning stochastic optimization algorithms. Conducted numerical experiments provide evidence that tMOPSO is effective at tuning under multiple OFE budget constraints.
关键词： Control parameter tuning,multiobjective optimization,objective function evaluation (OFE) budget.
更新于2025-09-23 15:19:57