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Evolutionary multi-task optimization for parameters extraction of photovoltaic models
摘要： As the demand for solar energy increases dramatically, the optimization and control of photovoltaic systems become increasingly important, accurate and reliable parameter identification of photovoltaic models is always required, which proposes an urgent need for accurate and robust algorithms. To this end, many heuristic algorithms have been proposed to extract the parameters of different photovoltaic models. However, they only extract the parameters of one model in a single run, which is inconsistent with the human ability to solve multiple tasks simultaneously and ignores the useful information derived from different models. Therefore, in this paper an evolutionary multi-task optimization algorithm is proposed to extract the parameters of multiple different photovoltaic models simultaneously. To be specific, the helpful information found by the population is transferred through the cross-task crossover to improve the performance in terms of solution quality and convergence rate of the population. The proposed algorithm is evaluated by extracting the parameters of three different models simultaneously, i.e., single diode, double diode, and photovoltaic module model. Comprehensive results demonstrate that the proposed algorithm has better performance with respect to the accuracy and robustness in comparison with other state-of-the-art algorithms.
关键词： Differential evolution,Parameter extraction,Evolutionary multi-task optimization,Photovoltaic models
更新于2025-09-16 10:30:52
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Optimisation of laser beam cutting parameters of high density composite fibre cement flat board
摘要： At the beginning of the research work we encountered two major problems. First, literature for laser beam machining of fibre cement is virtually zero. This fact does not exclude the research of the subject by others, of course, but it may in any case indicate its confidentiality (technological competitive advantage). Second, the exact composition of the fibre cement material is protected, but the boards we use are available from manufacturer by code number, so the experiment can be clearly reproduced. For this reasons, we have decided to use the rigid, classic Design of Experiments method. Based on our previous experience, the effect factors were chosen in the group of Laser power, Cutting velocity, Cutting gas pressure, Focal length, Laser frequency and Cutting gas type, at a total of 17 factor levels. The necessary and sufficient conditions are met by the 2-Factor-Interaction (2FI) fractional factorial experiments, instead of full factorial 6FI experiment series. Based on our very first experiments, it was found that the high-density composite fiber cement material can be cut with laser beam technology. Experiments and related visual and measurement responses clearly define the significant effect factors. The experiments proved our zero hypotheses, the "p-values", derived from the analysis of the response parameters, were below 0.05% (the significance limit usually is 0.1%), for each responses. We answered the questions of the fastest and cheapest technology lineup, to laser beam cut a composite fibre cement board to the desired size, with the expected quality.
关键词： Fibre cement,Design of Experiments,Parameter optimizing,Laser beam cutting
更新于2025-09-16 10:30:52
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Optical properties of fluidic defect states in one-dimensional graphene-based photonic crystal biosensors: visible and infrared Hall regime sensing
摘要： Advances in biotechnology are outpacing studies into the use of graphene in photonic biosensors due to its peculiar optical properties and the successful progress in the nanoscale integration of photonic crystals. Moreover, going beyond the usual Dirac cone approximation for graphene introduces nonlinear effects in graphene’s optics. In this work, by the use of the transfer matrix method, we investigate the effect of hopping parameter on the chemical and biosensing performance of a 1D defective photonic biosensor with a micro/nano?uidic channel as a central defect cavity for biological ?uids and gas molecules to ?ow while interacting with two graphene sheet deposited on silicon dioxide layers of the device. As low-weight molecules absorption on graphene’s surface could affect hopping energy of graphene which plays a signi?cant role in its optical conductivity obtained from the tight-binding model for the visible range, it will serve as a promising tool for the detection of gas and other analytes. We also examine the sensitivity of the defect modes to the changes of the refractive index of the biological ?uids under the in?uence of quantum Hall situation for graphene in terahertz (THz) regime. It is revealed that two defective modes with relatively different sensing properties are emerged within the band stop of the device. The results of this study are not reported elsewhere to the best of our knowledge.
关键词： photonic crystal,hopping parameter,terahertz,biosensor,optical conductivity,visible light,graphene,quantum Hall effect
更新于2025-09-16 10:30:52
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Research of Multimodal Medical Image Fusion Based on Parameter-Adaptive Pulse-Coupled Neural Network and Convolutional Sparse Representation
摘要： Visual effects of medical image have a great impact on clinical assistant diagnosis. At present, medical image fusion has become a powerful means of clinical application. The traditional medical image fusion methods have the problem of poor fusion results due to the loss of detailed feature information during fusion. To deal with it, this paper proposes a new multimodal medical image fusion method based on the imaging characteristics of medical images. In the proposed method, the non-subsampled shearlet transform (NSST) decomposition is first performed on the source images to obtain high-frequency and low-frequency coefficients. The high-frequency coefficients are fused by a parameter-adaptive pulse-coupled neural network (PAPCNN) model. The method is based on parameter adaptive and optimized connection strength β adopted to promote the performance. The low-frequency coefficients are merged by the convolutional sparse representation (CSR) model. The experimental results show that the proposed method solves the problems of difficult parameter setting and poor detail preservation of sparse representation during image fusion in traditional PCNN algorithms, and it has significant advantages in visual effect and objective indices compared with the existing mainstream fusion algorithms.
关键词： multimodal,medical image fusion,parameter-adaptive pulse-coupled neural network,convolutional sparse representation,non-subsampled shearlet transform
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE Canadian Conference of Electrical and Computer Engineering (CCECE) - Edmonton, AB, Canada (2019.5.5-2019.5.8)] 2019 IEEE Canadian Conference of Electrical and Computer Engineering (CCECE) - Parameter Estimation of Photovoltaic System Using Real Condition Data
摘要： Phovoltaic generation have been increasing around the world as an important alternative of energy production. Therefore, studies to foresee the impact of inclusion of this type of energy in the network become necessary. For this goal, the representation of these photovoltaic generators by equivalent model and the estimation of its parameter is an important area to study. Usually manufactures of photovoltaic modules provide some information to obtain model parameters of those panels using standard test conditions. However, in real situation, rarely those conditions are similar of those where the photovoltaic modules are installed. In this research a method for parameter estimation of equivalent photovoltaic power plant model is proposed using real measuremets. The improved single diode model was select to represent the photovoltaic system and the mean-variance mapping optimization method was used to estimate the parameters. A comparison between the parameter estimated with standard test condition and with real measurements was performed in a real photovoltaic system installed in Sao Paulo University. The results have shown differences between parameters estimated with real measurement compared with stander test condition, especially a parallel and series resistances.
关键词： parameter,Photovoltaic system,MVMO,estimation
更新于2025-09-12 10:27:22
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A capacitor based fast I-V characteristics tester for photovoltaic arrays
摘要： In order to efficiently evaluate the operating status of photovoltaic (PV) arrays, a design of fast current-voltage (I-V) characteristic tester is proposed in this paper. The tester uses the dynamic capacitor charging method to quickly sweep I-V characteristic curves. Then, a new artificial bee colony and Nelder-Mead simplex (ABC-NMS) hybrid algorithm is used to extract parameters of the single diode model of PV arrays. The experimental results show that the tester can quickly measure high-quality I-V curves of PV array and achieve accurate model parameters extraction. In addition, the root mean square error (RMSE) of curve fitting can be used to effectively indicate the partial shading condition.
关键词： I-V characteristics testing,ABC-NMS algorithm,dynamic capacitor charging,PV arrays,parameter extraction,partial shading
更新于2025-09-12 10:27:22
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Exact Parameter Identification of Photovoltaic Panel by Using Datasheet Details
摘要： This paper deals with two main aspects of Photovoltaic systems. One is the analysis of Photovoltaic panel using the datasheet values provided on the PV panel and the other is to find the exact values of parameters of PV panel. Characterization of PV panels refers to the ability to predict the panel's output for given ambient conditions. To predict the exact characteristics and for exact mathematical modeling of PV panel, it is essential to find the parameters of the solar panel rather than assuming the parameters in modeling. One of the objectives of this study is to find the parameters like series resistance and shunt resistance values in single diode model by analyzing the relationship between different parameters. The analyzing process will cover the parameter estimation from the given datasheet parameters of solar panel, and mathematical algorithm involved in finding the solar panel parameters.
关键词： Parameter identification,PV Panel,Exact modeling
更新于2025-09-12 10:27:22
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A Comparison of the Efficacy of Ablative Fractional Laser-assisted Photodynamic Therapy according to the Density of Ablative Laser Channel in the Treatment of Actinic Keratosis: A Prospective, Randomized, Controlled Trial
摘要： Photodynamic therapy (PDT) with methyl aminolevulinate (MAL) is effective in the treatment of actinic keratosis (AK). Protoporphyrin IX (PpIX) transformed from MAL is accumulated in abnormal AK cells, which are destroyed by light irradiation during PDT. However, AK hyperkeratosis is known to reduce the PDT treatment response, and pretreatment with ablative fractional laser (AFL) has been successfully used to overcome this barrier. AFL treatment creates microscopic ablation zones (MAZs), allowing easy absorption of MAL and direct evaporation of abnormal cells. We evaluated whether AFL pretreatment with different laser channel densities impacts the efficacy, PpIX accumulation, side effects, and cosmetic outcomes in AFL-PDT for facial AK. This study followed a previous study comparing the efficacy of AFL-PDT according to ablative depth for AK. Patients were randomly assigned to three different AFL density groups with other parameters being fixed. Each lesion was photographed and graded according to Olsen et al. Three hours after MAL application, fluorescence intensity was measured to assess PpIX accumulation and each area was irradiated with a red light-emitting diode lamp (peak emission 630; total light dose 37 J/cm2). Forty-seven Korean patients with 312 AK lesions completed the study (5.5-, 11-, and 22%-density AFL-PDT groups, 16 patients, n=110; 15 patients, n=96; and 16 patients, n=106, respectively). The three groups had no statistical differences in sex, age, Fitzpatrick score, number of lesions, or Olsen grade. However, the complete response (CR) rate was different between the 3 groups at months 3 and 12 (P=0.037; P=0.003, respectively) and the 22%-density AFL-PDT group showed a significantly higher CR rate than the 5.5%-density group (3 months, 88.7% vs. 80.0%; 12 months, 81.1% vs. 60.9%). The CR rate of the different laser densities was investigated for each Olsen grade, and the 22%-density group showed a significantly higher CR rate than the 5.5%-density group (3 months, 81.3% vs. 55.9%; 12 months, 68.8% vs. 38.2%) in Olsen grade III AK lesions. The fluorescence intensities measured and calculated from the photographs were not different among the three groups, and side effects and cosmetic outcomes showed no significant difference. In this study, the CR rate of AFL-PDT was different among the 3 groups, though there were no differences in PpIX accumulation. A recent study also demonstrated that PpIX accumulation showed no difference at laser densities above 5% when AFL is performed in normal skin. However, higher laser density AFL evaporates AK tissues more, and another study showed that AFL treatment temporarily reduced AKs and showed a trend toward decreased development of new lesions. This study had limitations with the small sample size in a single ethnic group, and more studies on AFL-PDT laser density, especially density > 22%, are needed. In conclusion, the group treated with AFL-PDT with higher laser density showed a better CR rate with reduced recurrence, especially for AK with higher Olsen grade. We recommend pretreatment with AFL at a higher laser density when AFL-PDT is used to treat AK with severe hyperkeratosis.
关键词： actinic keratosis,photodynamic therapy,laser parameter,ablative factional laser,laser channel density
更新于2025-09-12 10:27:22
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A new approach for parameter estimation of the single-diode model for photovoltaic cells/modules
摘要： Solar energy has become a popular renewable energy source, leading to wide use of photovoltaic (PV) cells/modules in energy production. For this reason, realistic modeling of PVs and determining the equivalent circuit parameters is of great importance in terms of planning and operation. Hence, in this study, an analytical model for identifying the single-diode equivalent circuit parameters; series resistance ( Rs ), shunt resistance ( Rp ), diode ideality factor ( a ), diode reverse-saturation current ( Io ), and photon current ( Ipv ) for PV cells/modules is developed without neglecting any term. In order to test the accuracy of the model, a number of PV modules from different manufacturers are taken into account and the results are compared with those obtained by using such analytical models given in the literature. Current-voltage (I-V ) characteristics of the PV modules, which are studied here, are also simulated by comparing with the experimental I-V curves provided by the manufacturers. Results show that the values of the parameters obtained for the PV modules are consistent with those extracted by using other analytical models. In addition, I-V curves created by using the obtained parameters are in full agreement with the experimental data. The curves also show a high degree of compatibility with the ones created by using the optimal parameters of the two-diode models given in the literature. Moreover, the proposed model provides a great advantage in estimating equivalent circuit parameters in terms of ease of use, requirements for input data, dependency on initial conditions as well as considering the parameters which are neglected in such methods given in the literature.
关键词： Photovoltaic cells/modules,single-diode model,mathematical modeling,parameter extraction
更新于2025-09-12 10:27:22
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The spectroscopic properties of the low-lying excited states and laser cooling scheme of SrBr molecule
摘要： The potential energy curves and the transition dipole moments for seven electronic states of SrBr molecule are obtained via the multi-reference configuration interaction method and the all-electron basis sets. The Davidson and relativistic corrections are also included. Based on the obtained potential energy curves, the rotational and vibrational energy levels of each electronic state are determined by solving the nuclear motion equation of the molecule. The spectroscopic parameters are fitted from the obtained energy levels by using Dunham expression. Moreover, the spin-orbit coupling splits of the A2Π state are considered to construct the optical laser cooling scheme. The Frank-Condon factors, radiation lifetimes, radiation widths between the ground electronic state and 2Π1/2, 3/2/B2Σ+ states are calculated. Then, the feasibility of laser cooling is explored and the optical scheme is proposed. The results demonstrate that the SrBr molecule is a promising candidate for laser cooling.
关键词： Frank-Condon factors,optical scheme,laser cooling,Radiative lifetime,Spectroscopic parameter
更新于2025-09-12 10:27:22