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Sensitivity Analysis of Multifrequency MIMP SAR Data From Rice Paddies
摘要： The determination of the accurate composition ratio of scattering mechanisms (volume scattering, double-bounce scattering, and surface scattering) within a radar backscatter is essential to validate current polarimetric decomposition techniques. Multiincidence angle and multipolarimetric synthetic aperture radar (MIMP SAR) observations at the X- and L-bands were applied to rice paddies at late vegetative stage in Niigata City in Japan in 2014 and 2016, respectively. In this paper, multifrequency MIMP SAR analysis is introduced based on the observation results. The approach, combined with theoretical characterization of the data by a discrete scatterer model, showed that rice panicles affect the backscatter from rice paddies. Contrary to expectation, an effect of transmissivity by using different bands is not obvious. The similar level of copolarization (HH and VV) backscatter at X- and L-bands could be explained by the effective size of rice panicles. They are the most characteristic scatters in rice paddy field with respect to multiple frequency polarimetric sensing. In addition, HV shows a distinct sensitivity to the mean orientation angle and the size of panicles regardless of the wavelength. The mean orientation angle affects the polarimetric randomness under azimuthal symmetry, whereas the size of panicles directly affects the attenuation of the volume scattering from the grains. The multifrequency MIMP SAR analysis also indicated the importance of considering the backscatter and attenuation in the interpretation of the backscattering cross section from vegetated fields.
关键词： rice paddies.,multifrequency multiincidence angle and multipolarimetric synthetic aperture radar (MIMP SAR),Discrete scatterer model (DSM)
更新于2025-09-23 15:23:52
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Dynamic Behavioral Modeling of RF Power Amplifier Based on Time-Delay Support Vector Regression
摘要： A new, dynamic behavioral modeling technique, based on a time-delay support vector regression (SVR) method, is presented in this paper. As an advanced machine learning algorithm, the SVR method provides an effective option for behavioral modeling of radio frequency (RF) power amplifiers (PAs), taking into account the effects of both device nonlinearity and memory. The basic theory of the proposed modeling technique is given, along with a detailed model extraction procedure. Unlike traditional artificial neural network (ANN) techniques, which take time to determine the best configuration of the model, the SVR method can obtain the optimal model in short time, using the grid-search technique. An example of an optimal SVR model selection applied to an RF PA is also given; the performance of the selected model presents a big improvement when compared with the default SVR model. Experimental validation is performed using an LDMOS PA, a single device gallium nitride (GaN) PA, and a Doherty GaN PA, revealing that the new modeling methodology provides very efficient and extremely accurate prediction. Compared with traditional Volterra models, canonical piecewise linear models, and ANN-based models, the proposed SVR model gives improved performance with reasonable complexity. In addition, it is shown that the model can predict accurately the behavior of the PA under input power levels that are different from those under which it is extracted.
关键词： time delay,radio frequency (RF) power amplifiers (PAs),machine learning,Dynamic behavioral model,support vector regression (SVR)
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE PELS Workshop on Emerging Technologies: Wireless Power Transfer (WoW) - Montréal, QC, Canada (2018.6.3-2018.6.7)] 2018 IEEE PELS Workshop on Emerging Technologies: Wireless Power Transfer (Wow) - Modeling and Analysis Methods for the DWPT System Applicated in EVs Charging
摘要： The difficulty of modeling a dynamic wireless power transfer (DWPT) system for Electric Vehicles(EVs) charging is that its mutual inductance changes with the coil offset, so we have to build a dynamic model of the system. In this paper,we propose a modeling method by using equivalent circuit method and state space averaging.Moreover,based on the set of system parameters,comparing the results of the simulation experiment with the result of the model calculation.At last, the performance indexes of the system under the different buck duty cycle are observed. The simulation results of these indexes are also basically consistent with the model calculation results, which further verify the accuracy of the model.At the same time,we found that the selection of duty cycle has a great influence on the performance indexes.
关键词： Dynamic Wireless Power Transfer (DWPT),Equivalent Circuit Method,Electric Vehicles(EVs),State Space Averaging,Dynamic Model
更新于2025-09-23 15:23:52
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[IEEE 2018 XIV International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) - Novosibirsk, Russia (2018.10.2-2018.10.6)] 2018 XIV International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) - Universal Control System of a Semiconductor Electric Energy Converter on Programmable Logic Devises
摘要： The article presents the results of the development of a universal control system for semiconductor power converters based on a programmable logic devices (PLD). As a result of the work done, shared functional modules for the various control systems of semiconductor converters were determined, the features of implementing modules on programmable logic were considered, and the algorithms for controlling converters on mathematical models were studied. The principal circuit diagram of the universal control system of the converter is synthesized on the basis of a combination of programmable logic devises and a microcontroller. The topologies of printed circuit boards and their layout in a single module of the universal control system of the converter are developed; the built-in microcontroller software was written and debugged in the assembler language. An experimental sample of the control system was made and its joint tests with a prototype of a low-power three-phase inverter equipped with a load simulator were carried out, oscillograms of control pulses and output voltage were obtained in various modes of inverter control.
关键词： digital control system,programmable logic device,algorithm,semiconductor power converter,model
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Hybrid Parametric - Nonparametric Target Detector for Hyperspectral Images
摘要： In this work a novel target detector is proposed that is nonparametric in terms of conditional probability density function (pdf) estimation and parametric with respect to the target strength of the additive model it relies upon. The variable bandwidth kernel density estimator is employed to estimate the conditional pdfs, whereas the target strength is estimated via the Maximum Likelihood approach. Experimental results over real hyperspectral data show that the detector succeeds in detecting target objects embedded in a complex background and in providing reasonable estimates for the target strengths.
关键词： nonparametric approach,kernel density estimation,additive model,target detection,Hyperspectral imaging
更新于2025-09-23 15:23:52
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Spectral analysis for photoacoustic pressure sensor designs: Theoretical model improvement and experimental validation
摘要： In the pulsed laser photoacoustic (PA) detection and spectroscopy applications, the fundamental frequency of the PA signal produced, and the sensor resonance frequency should be as close as possible to each other so that analyzes from the obtained signals can be performed effectively. In order to determine the fundamental frequency of the PA wave, a theoretical model approach based on the development of the frequency domain solution of the PA wave equation is presented for use in the PA pressure sensor designs. For the validation of the theoretical model approach, a PA experimental setup was established, and measurements were made in distilled water. The theoretical and experimental PA frequency spectra were determined to be very compatible with each other. Thus, the theoretical model approach was experimentally validated. According to the theoretical model approach, fundamental frequency values obtained from the experimental measurement results were determined with an average accuracy of ? 4.212%. Furthermore, it has been determined that this value has fallen to ?0.267% in the measurements. With the obtained results from the theoretical model approach, we propose that PA pressure sensors with the more selective and narrower band can be designed for more sensitive detection. Moreover, in this study the effects of different laser parameters such that pulse duration, and laser beam width, on the spectral content of the obtained PA signal are analyzed. These analyses will shed light on the vision of acoustic pressure sensor design by helping to select the most optimum parameters for PA detection.
关键词： Theoretical model approach,Photoacoustic wave equation,Acoustic pressure sensor,Frequency domain solution,Pulsed laser photoacoustic method,Spectroscopy
更新于2025-09-23 15:23:52
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Finite Element Analysis to the Constitutive Behavior of Sintered Silver Nanoparticles Under Nanoindentation
摘要： Finite element (FE) simulation is adopted as a fundamental tool to evaluate the mechanical reliability of packaging structures for electronic devices. Nevertheless, the determination of mechanical properties of sintered silver nanoparticles (AgNP) remains challenging as the traditional tensile test is difficult to be performed at a limited size. In the current study, spherical nanoindentation is utilized to measure the applied load-penetration depth responses of sintered AgNP reinforced by SiC microparticles at various weight ratios (0.0, 0.5, 1.0 and 1.5 wt.%). To describe the elasto-plastic behavior of this heterogeneous material, FE analysis is performed to simulate the indentation behavior and determine the parameters in the modified power-law model by fitting the average applied load-penetration depth responses. To overcome the uniqueness problem, the Young’s modulus is directly determined by continuous stiffness measurement technique and the proposed constitutive model can provide a reasonably accurate mechanical estimation of sintered AgNP. The effect of SiC content on sintered AgNP is discussed by correlating the morphology observed by scanning electron microscope (SEM) and the constitutive parameters obtained from the FE simulations.
关键词： nanoindentation,finite element analysis.,constitutive model,SiC microparticle,Sintered silver nanoparticle
更新于2025-09-23 15:23:52
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Proposal of Novel Optical Model for Light-Diffusing Film Having Alternating Polymer Layers with Different Refractive Indices
摘要： We have proposed the novel optical model for layer structure film to precisely control light diffusion angle range. By introducing structure characteristics to the phase grating model, we successfully constructed the novel optical model. In addition, we clarified that difference of refractive indices of layer structure and layer width are important factors for precisely control of light diffusion angle range.
关键词： diffraction,light-diffusing film,optical model,refractive index,layer structure
更新于2025-09-23 15:23:52
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Improved three-vector based dead-beat model predictive direct power control strategy for grid-connected inverters
摘要： Since only one inverter voltage vector is applied during each duty cycle, traditional model predictive direct power control (MPDPC) for grid-connected inverters (GCIs) results in serious harmonics in current and power. Moreover, a high sampling frequency is needed to ensure satisfactory steady-state performance, which is contradictory to its long execution time due to the iterative prediction calculations. To solve these problems, a novel dead-beat MPDPC strategy is proposed, using two active inverter voltage vectors and one zero inverter voltage vector during each duty cycle. Adoption of three inverter vectors ensures a constant switching frequency. Thus, smooth steady-state performance of both current and power can be obtained. Unlike the traditional three-vector based MPDPC strategy, the proposed three vectors are selected based on the power errors rather than the sector where the grid voltage vector is located, which ensures that the duration times of the selected vectors are positive all the time. Iterative calculations of the cost function in traditional predictive control are also removed, which makes the proposed strategy easy to implement on digital signal processors (DSPs) for industrial applications. Results of experiments based on a 1 kW inverter setup validate the feasibility of the proposed three-vector based dead-beat MPDPC strategy.
关键词： Grid-connected inverter,Model predictive control,Constant switching frequency,Power errors,Direct power control,Three vectors
更新于2025-09-23 15:23:52
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Protein-Protein Interactions of Highly Concentrated Monoclonal Antibody Solutions via Static Light Scattering and Influence on the Viscosity
摘要： The ability to design and formulate mAbs to minimize attractive interactions at high concentrations is important for protein processing, stability and administration, particularly in subcutaneous delivery, where high viscosities are often challenging. The strength of protein-protein interactions (PPI) of an IgG1 and IgG4 monoclonal antibody (mAb) from low to high concentration were determined by static light scattering (SLS) and used to understand viscosity data. The PPI were tuned using NaCl and five organic ionic co-solutes. The PPI strength was quantified by the normalized structure factor S(0)/S(0)HS and Kirkwood-Buff integral G22/G22,HS (HS = hard sphere) determined from the SLS data, and also by fits with (1) a spherical Yukawa potential and (2) an interacting hard sphere (IHS) model, which describes attraction in terms of hypothetical oligomers. The IHS model was better able to capture the scattering behavior of the more strongly-interacting systems (mAb and/or co-solute) than the spherical Yukawa potential. For each descriptor of PPI, linear correlations were obtained between the viscosity at high concentration (200 mg/mL) and the interaction strengths evaluated both at low (20 mg/mL) and high concentration (200 mg/mL) for a given mAb. However, the only parameter that provided a correlation across both mAbs was the oligomer mass ratio (moligomer/mmonomer+dimer) from the IHS model, indicating the importance of self-association (in addition to the direct influence of the attractive PPI) on the viscosity.
关键词： Protein-protein interactions,static light scattering,co-solutes,monoclonal antibody,viscosity,interacting hard sphere model,Yukawa potential
更新于2025-09-23 15:23:52