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- 2019
- Distributed optical fiber sensing
- Optical frequency domain reflection
- Polynomial regression algorithm
- Nonlinear tuning compensation
- Optoelectronic Information Science and Engineering
- Hebei University of Technology
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An image features assisted line selection method in laser-induced breakdown spectroscopy
摘要： Analytical lines play a crucial role in laser-induced breakdown spectroscopy (LIBS) technology. To improve the classification performance of LIBS, an image features assisted line selection (IFALS) method which based on spectral morphology and the characteristics of Harris corners was proposed. With this method, a classification experiment for 24 metamorphic rock samples was conducted with linear discriminant analysis (LDA) algorithm. The result showed that the classification accuracy was increased from 94.38% of the conventional classification model MLS-LDA (Manual line selection-linear discriminant analysis) to 98.54% of IFALS-LDA. Furthermore, the time required for the whole classification process was decreased from 2768.38 seconds of MLS-LDA to 4.36 seconds of the proposed method, thus the classification efficiency was greatly improved. In addition, compared with the existing automatic line selection method, the convergence rate of IFALS-LDA is significantly faster than that of ASPI (Automatic Spectral Peaks Identification)-LDA. This study demonstrates that LIBS assisted with the image features in machine vision can promote the analytical performance of LIBS technology.
关键词： Laser-induced breakdown spectroscopy,metamorphic rock,image features,linear discrimination analysis,analytical line selection
更新于2025-09-23 15:19:57
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Laser cutting optimization model with constraints: Maximization of material removal rate in CO <sub/>2</sub> laser cutting of mild steel
摘要： Taking full advantage of what laser cutting technology offers in terms of achieving superb quality cuts at low cost and high production rates requires the optimization of laser cutting parameters. This implies the need to formulate and solve different laser cutting optimization problems. In this article, an optimization model for CO2 laser cutting of mild steel is developed. The laser cutting optimization problem was explicitly formulated as a single-objective optimization problem with five non-linear constraints of the equality, inequality and range type. The goal was to determine the laser cutting parameter values so as to maximize the material removal rate while simultaneously considering practical process constraints related to dross formation, kerf width, perpendicularity deviation, surface roughness and severance energy. Two crossed experimental designs of different resolutions were performed in order to define six mathematical models, which were used in the formulation of the optimization problem. For the purpose of optimization, the exhaustive iterative search algorithm was applied, since it determines solutions whose optimality is guaranteed in the given discrete space of input variable values. The practical usability of the developed laser cutting optimization model and the effectiveness of the applied optimization approach were proved while solving a real case study aimed at the optimization of laser cutting parameters for cutting parts for the furnace industry.
关键词： mild steel,CO2 laser cutting,optimization model,material removal rate,non-linear constraints
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) - Test-Based Modeling of Photovoltaic Inverter Impact on Distribution Systems
摘要： AC voltage regulation is required in both the domestic and industrial sectors to avoid undesired effects from random voltage variations of the power supply. The paper introduces an ac voltage stabilizer/converter (ACVS) that is based on a controllable autotransformer technology. The proposed ACVS offers a specified strategy of voltage regulation, less harmonics, and low cost. The paper explains the operating principle of the ACVS and derives its nonlinear mathematical model. To ensure the desired performance of the ACVS while it is subject to uncertain input voltage and load variations, an optimal control strategy is designed. It is achieved via transforming the ACVS model extending with fictive axis emulation into a rotating reference frame and the linearization of the model via specific orientation of the reference frame and introducing a linear control action. Operation of the ACVS is simulated under different disturbances due to load and grid voltage changes, and compared to voltage stabilization with application of I and PI controllers. Experimental results are presented to demonstrate the voltage regulation technology.
关键词： AC–AC power conversion,electric variables control,linear-quadratic control,power quality,voltage control
更新于2025-09-23 15:19:57
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Communication A Planar Angled-Dipole Antenna With Quasi-Isotropic Radiation Pattern
摘要： Epilepsy is a brain disorder, where patients’ lives are extremely disturbed by the occurrence of sudden unpredictable seizures. This paper develops patient-independent signal processing techniques based on common spatial patterns and linear discriminant analysis to detect epileptic activities (spikes) from multi-channel brain signal recordings. In contrast to current existing studies which heavily rely on the analysis of electroencephalogram (EEG) data for the detection of epileptic activities, this research work considers magnetoencephalography (MEG) recordings for the detection of epileptic spikes. This requires careful development since unlike EEG spikes, MEG spikes do not have well-defined morphological characteristics. Due to the recent advances in MEG technology, it became possible to consider MEG signals to detect and analyze epileptic activities, but efforts to develop signal processing tools in this area are still in its outset, as compared with those devoted to EEG signal processing.
关键词： MEG,Epileptic spikes detection,linear discriminant analysis,common spatial patterns
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) - Performance Study of Lattice-Matched Multijunction Solar Cells Incorporating GaInNAsSb Junctions with 0.7 - 1.4 eV Bandgap
摘要： Parking in major cities, particularly with dense traffic, directly effects the traffic flow and people’s life. In this paper, we introduce a new smart parking system that is based on intelligent resource allocation, reservation, and pricing. The proposed system solves the current parking problems by offering guaranteed parking reservations with the lowest possible cost and searching time for drivers and the highest revenue and resource utilization for parking managers. New fair pricing policies are also proposed that can be implemented in practice. The new system is based on mathematical modeling using mixed-integer linear programming (MILP) with the objective of minimizing the total monetary cost for the drivers and maximizing the utilization of parking resources.
关键词： dynamic resource allocation,smart car parking,mixed integer linear programming (MILP),reservation,Dynamic pricing
更新于2025-09-23 15:19:57
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Effect of Secondary Emission Yield and Initial Charge of Dielectric Material on Multipactor in Parallel-Plate Dielectric-Loaded Waveguide
摘要： We present a theoretical analysis and comparison of the effect of (cid:2)1 versus (cid:2)2 regularization for the resolution of ill-posed linear inverse and/or compressed sensing problems. Our formulation covers the most general setting where the solution is speci?ed as the minimizer of a convex cost functional. We derive a series of representer theorems that give the generic form of the solution depending on the type of regularization. We start with the analysis of the problem in ?nite dimensions and then extend our results to the in?nite-dimensional spaces (cid:2)2(Z) and (cid:2)1(Z). We also consider the use of linear transformations in the form of dictionaries or regularization operators. In particular, we show that the (cid:2)2 solution is forced to live in a prede?ned subspace that is intrinsically smooth and tied to the measurement operator. The (cid:2)1 solution, on the other hand, is formed by adaptively selecting a subset of atoms in a dictionary that is speci?ed by the regularization operator. Beside the proof that (cid:2)1 solutions are intrinsically sparse, the main outcome of our investigation is that the use of (cid:2)1 regularization is much more favorable for injecting prior knowledge: it results in a functional form that is independent of the system matrix, while this is not so in the (cid:2)2 scenario.
关键词： linear inverse problems,compressed sensing,regularization,Sparsity,total variation,(cid:2)1-norm minimization
更新于2025-09-23 15:19:57
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[IEEE 2019 International Multi-Conference on Engineering, Computer and Information Sciences (SIBIRCON) - Novosibirsk, Russia (2019.10.21-2019.10.27)] 2019 International Multi-Conference on Engineering, Computer and Information Sciences (SIBIRCON) - The Use of Spread Spectrum Signals to Increase the Noise Immunity of Optical Communication Systems Based on the Effect of LED Reversibility
摘要： Data mining applications are becoming a more common tool in understanding and solving educational and administrative problems in higher education. In general, research in educational mining focuses on modeling student’s performance instead of instructors’ performance. One of the common tools to evaluate instructors’ performance is the course evaluation questionnaire to evaluate based on students’ perception. In this paper, four different classi?cation techniques—decision tree algorithms, support vector machines, arti?cial neural networks, and discriminant analysis—are used to build classi?er models. Their performances are compared over a data set composed of responses of students to a real course evaluation questionnaire using accuracy, precision, recall, and speci?city performance metrics. Although all the classi?er models show comparably high classi?cation performances, C5.0 classi?er is the best with respect to accuracy, precision, and speci?city. In addition, an analysis of the variable importance for each classi?er model is done. Accordingly, it is shown that many of the questions in the course evaluation questionnaire appear to be irrelevant. Furthermore, the analysis shows that the instructors’ success based on the students’ perception mainly depends on the interest of the students in the course. The ?ndings of this paper indicate the effectiveness and expressiveness of data mining models in course evaluation and higher education mining. Moreover, these ?ndings may be used to improve the measurement instruments.
关键词： linear discriminant analysis,Arti?cial neural networks,support vector machines,decision trees,classi?cation algorithms,performance evaluation
更新于2025-09-23 15:19:57
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A Report on Growth And Spectroscopic Studies on The L-Tartaric Acid Doped Potassium Dihydrogen Phosphate Non-Linear Optical Single Crystals
摘要： In recent years study of non-linear optical (NLO) materials is gaining rapid momentum due to their needs in several device applications. Potassium Dihydrogen Phosphate (KDP) is a well-known NLO material, whose non-linearity is enhanced by doping with amino acids. In this present study, single crystal of L-Tartaric acid doped potassium Dihydrogen phosphate (LTKDP) have been grown by slow evaporation method at room temperature. Good quality transparent crystals were obtained with 27-30 days. The crystallinity and cell parameters were characterized by X-ray diffraction analysis (XRD), the shifts in frequency assignments of various functional groups of KDP due to the addition of L-Tartaric acid was analysed by Fourier transform infrared (FTIR) and Fourier transform Raman spectroscopic studies. The dielectric constant and the dielectric loss of the single crystals were studied as a function of frequency. Kurtz- Perry power technique was employed to determine the Second Harmonic Generation (SHG) efficiency of LTKDP single crystal.
关键词： X-ray diffraction,SHG efficiency,L-Tartaric acid,slow evaporation method,FT-Raman,Potassium Dihydrogen Phosphate,FTIR,non-linear optical materials
更新于2025-09-23 15:19:57
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A fluorometric aptasensor for bisphenol a based on the inner filter effect of gold nanoparticles on the fluorescence of nitrogen-doped carbon dots
摘要： An aptamer-based fluorometric assay is described for the determination of bisphenol A (BPA). The aptamer against BPA is first attached to the surface of the red AuNPs, and this prevents the AuNPs from salt-induced formation of a blue-colored aggregate. Hence, the blue fluorescence of added nitrogen-doped carbon dots (NCDots) is quenched via an inner filter effect (IFE) caused by the red AuNPs. After addition of BPA, the BPA/aptamer complex is formed, and the AuNPs are no longer stabilized agains aggregation. This weakens the IFE and results in the recovery of the fluorescence of the NCDots which is measured best at excitation/emission wavelengths of 300/420 nm. The recovered fluorescence increases linearly in the 10 to 250 nM and 250 to 900 nM BPA concentration ranges, and the detection limit is 3.3 nM. The method was successfully applied to the determination of BPA in spiked environmental tap water samples.
关键词： Wide linear range,Quick response,Salt-induced aggregation,Tap water,Low detection limit,BPA/aptamer complexes,Aggregated AuNPs,Environmental-friendly,Fluorescence quenched,Fluorescence recovery
更新于2025-09-23 15:19:57
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Performance Analysis of Mixed Carrier-pulse Width Modulation Scheme
摘要： This study deals with the performance analysis of Pulse Width Modulation (PWM) scheme for three phase voltage source inverter though intermingling of multiple carriers. The proposed PWM scheme using two groups of carriers (inverted Sine wave and Triangle wave), each group having carrier and its 90° shifted. The arbitrary selection of these carriers is based on the linear feedback shift registers value (‘0’ or ‘1’). This random carrier selection is serving to improve the spectral quality of the output of the inverter. This improved waveform has been derived from third harmonic injected sine PWM technique. Simulation results confirm the effectiveness of the proposed scheme in providing very less harmonic noises with minimum distortion and satisfactory fundamental component. This study also shows the implementation compatibility of the work with Field Programmable Gate Array environment.
关键词： Harmonic spread factor,voltage source inverter,linear feedback shift register,random pulse width modulation,pseudo random binary sequence
更新于2025-09-23 15:19:57