A Residual Frequency Offset Estimation Method Based on Range Migration Fitting

Recently,researchers have proposed an emitter localization method based on passive synthetic aperture.However,the unknown residual frequency offset(RFO)between the transmit-ter and the receiver causes the received Doppler signal to shift,which affects the localization accu-racy.To solve this issue,this paper proposes a RFO estimation method based on range migration fitting.Due to the high frequency modulation slope of the linear frequency modulation(LFM)-mod-ulation radar signal,it is not affected by RFO in range compression.Therefore,the azimuth time can be estimated by fitting the peak value position of the pulse compression in range direction.Then,the matched filters are designed under different RFOs.When the zero-Doppler time obtained by the matched filters is consistent with the estimated azimuth time,the given RFO is the real RFO between the transceivers.The simulation results show that the estimation error of azimuth distance does not exceed 20 m when the received signal duration is not less than 3 s,the pulse repe-tition frequency(PRF)of the transmitter radar signal is not less than 1 kHz,the range detection is not larger than 1000 km,and the signal noise ratio(SNR)is not less than-5 dB.

A Robust Indoor Localization Algorithm Based on Polynomial Fitting and Gaussian Mixed Model

Wireless sensor network(WSN)positioning has a good effect on indoor positioning,so it has received extensive attention in the field of positioning.Non-line-of sight(NLOS)is a primary challenge in indoor complex environment.In this paper,a robust localization algorithm based on Gaussian mixture model and fitting polynomial is proposed to solve the problem of NLOS error.Firstly,fitting polynomials are used to predict the measured values.The residuals of predicted and measured values are clustered by Gaussian mixture model(GMM).The LOS probability and NLOS probability are calculated according to the clustering centers.The measured values are filtered by Kalman filter(KF),variable parameter unscented Kalman filter(VPUKF)and variable parameter particle filter(VPPF)in turn.The distance value processed by KF and VPUKF and the distance value processed by KF,VPUKF and VPPF are combined according to probability.Finally,the maximum likelihood method is used to calculate the position coordinate estimation.Through simulation comparison,the proposed algorithm has better positioning accuracy than several comparison algorithms in this paper.And it shows strong robustness in strong NLOS environment.

Comparative Analysis of Equal and Unequal Grounding Grid Configurations by Compression Ratio and Least Square Curve Fitting Techniques

The primary aim of the power system grounding is to safeguard the person and satisfying the performance of the power systemtomaintain reliable operation.With equal conductor spacing grounding grid design,the distribution of the current in the grid is not uniform.Hence,unequal grid conductor span in which grid conductors are concentrated more at the periphery is safer to practice than equal spacing.This paper presents the comparative analysis of two novel techniques that create unequal spacing among the grid conductors:the least-square curve fitting technique and the compression ratio techniquewith equal grid configuration for both square and rectangular grids.Particle Swarm Optimization(PSO)is adopted for finding out one optimal feasible solution among many feasible solutions of equal grid configuration for both square and rectangular grids.Comparative analysis is also carried out between square and rectangular grids using the least square curve fitting technique as it results in only one unequal grid configuration.Simulation results are obtained by theMATLAB software developed.Percentage of improvement in ground potential rise,step voltage,touch voltage,and grid resistancewith variation in compression ratios are plotted.

Application of Flipped Classroom Teaching Model Based on Micro-Course in Practical Training Teaching of Contact Lens Fitting Technology

Objective:This paper aims to study the application of flipped classroom teaching model based on micro-course in the practical training teaching of contact lens fitting technology.Methods:From September 21 to July 23,120 students majoring in ophthalmology and optometry were selected and randomly divided into groups.The control group adopted the traditional teaching mode,and the study group adopted the flipped classroom teaching mode based on micro-course.Teaching scores and the skills,observation and judgment,adaptability,and communication skills were compared between the groups.Results:Statistical comparison of teaching scores under different management methods showed that the clinical thinking score and practice work quality in the study group were higher than those of the control group,and the effect of the study group was better(P<0.05).The overall scores of skills,observation and judgment,adaptability,and communication skills of the study group were better than those in the control group,and the comprehensive ability scores in the two groups were significantly different(P<0.05).Conclusion:In practical training teaching of contact lens fitting technology,the application of flipped classroom teaching based on micro-course can improve the skill scores of personnel,and the overall effect is good.This can lay the foundation for advanced ophthalmology and optometry talents with profound theoretical knowledge and professional skills.

基于Vector Fitting的光伏并网逆变器控制器参数频域辨识方法

光伏并网逆变器通常含有内外环、锁相环等不同带宽控制环节,且控制器参数往往并不可知,即存在“灰箱”问题。为准确辨识不同带宽控制器参数,提出一种基于端口导纳特性的光伏并网逆变器控制器参数频域辨识方法。首先,建立典型控制下光伏并网逆变器交流端口的dq理论导纳模型,得到其理论导纳标准式;然后,通过扫频手段获得光伏并网逆变器交流端口的测量导纳数据,并采用Vector Fitting算法对测量的端口导纳数据进行矢量拟合,得到拟合导纳标准式;最后,运用最小二乘原理使理论导纳标准式与拟合导纳标准式对应项系数差值的平方和最小,从而辨识得到光伏并网逆变器控制器参数的估计值。参数辨识实例表明,所提方法能够同时准确辨识出不同带宽控制器参数。

Prosthetic modeling for femoral head based on ellipsoid fitting

A novel modeling method which can restore the shape of the femoral head with collapse induced by ischemic necrosis is proposed. First, sequential tomograms of the hip are obtained from a CT scan; secondly, an accurate and automatic method is used to extract the profile of the acetabulum; thirdly, a hybrid method is utilized to gather fiducial marks on the acetabulum; fourthly, bulky error sampling points are removed. Finally, an ellipsoid fitting method is used to fit the ellipsoid model of the femoral head. Two male sufferers with different necrosis extents are chosen as experimental subjects for contrastive simulation. Fifty cases of different ages （from 25 to 79 years old） are utilized for statistical comparisons of matching errors. The prosthetic models highly resemble the primary shape of the femoral head in health. This new method provides not only a theoretical model for accurate operation position fixing in an orthopaedics clinic, but it is also an innovative practical means for the individual manufacture of artificial femoral heads.

FITTING CORRECTION METHOD OF RING ARTIFACTS FOR RECONSTRUCTING CONE-BEAM CT IMAGES

In high-resolution cone-beam computed tomography （CBCT） using the flat-panel detector, imperfect or defect detector elements cause ring artifacts due to the none-uniformity of their X-ray response. They often disturb the image quality. A dedicated fitting correction method for high-resolution micro-CT is presented. The method converts each elementary X-ray response curve to an average one, and eliminates response inconsistency among pixels. Other factors of the method are discussed, such as the correction factor variability by different sampling frames and nonlinear factors over the whole spectrum. Results show that the noise and artifacts are both reduced in reconstructed images

The numerical simulation and inversion fitting of radon concentration distribution in homogeneous overburden above active fault zones

Based on the convection and diffusion mechanisms of radon migration, in this paper we deduce the two-dimensional differential equation for radon transportation in the overburden above active fault zones with an unlimited extension along the strike. Making use of the finite difference method, the radon concentration distribution in the overburden above active faults is calculated and modeled. The active fault zone parameters, such as the depth and the width of the fault zone, and the value of radon concentration, can be inverted from the measured radon concentration curve. These realize quantitative interpretation for radon concentration anomalies. The inversion results are in good agreement with the actual fault zone parameters.

Detection of Broad Bean Diseases by Fourier Transform Infrared Spectroscopy Combined with Curve Fitting

Fourier transform infrared （FTIR） spectroscopy was used to study diseased leaves in broad bean. Results showed that the infrared spectra of different broad bean diseased leaves were similar, which were mainly made up of the vibrational absorption bands of protein,lipid and polysaccharide.There were minor differences in-cluding the spectral peak position, peak shape and the absorption intensity in the range of 1 800-1 300 cm-1. There were obvious differences among their second derivative spectra in the range of 1 800-1 300 cm-1. After the procedure of the Fourier self-deconvolution and curve fitting of health bean leaves and broad bean diseased leaves in the range of 1 700-1 500 cm-1, three sub-peaks were obtained at 1 550 cm-1 （protein amide Ⅱ band）, 1 605 cm-1 （lignin） and 1 650 cm-1 （protein amide I band）.The ratios of relative areas of the bands of amide Ⅱ, lignin, and amide I were 38.86%, 28.68% and 32.47% in the spectra of healthy leaves, respec-tively. It was distinguished from the diseased leaves （chocolate spot leaf： 15.42%, 42.98% and 41.61%, ring spot leaf：32.39%, 35.63% and 31.98%, rust leaf： 13.97%, 46.40% and 39.65%, yel owing leaf curl disease leaf： 24.01%,36.55% and 39.44%）. For sub-peak area ratios （A1 563/A1 605, A1 650/A1 605 and A1 563/A1 654）, those of four kinds of diseased leaves were smal er than that of healthy leaves, and there were also differences among four kinds of diseased leaves. The results proved that FTIR combining with curve fitting might be a potential y useful tool for detecting different kinds of broad bean diseases.

CAN总线转网络化井下遥传仪器通讯系统设计

为了解决采用网络化架构设计的测井地面系统与采用CAN总线接口设计的井下仪器的互联通讯问题,设计开发了专用的井下遥传COM转接板,其硬件系统基于ARM+DSP双控制芯片架构设计,同时实现TCP/IP网络接口与CAN接口;板级程序基于嵌入式实时操作系统实现,采用模块化的方式实现协议互转,模块开发相对独立且耦合程度低。该COM转接板目前已经大量应用于快速成像过钻具测井系统(FITS)中,实现了FITS地面控制系统与井下各仪器之间实时、可靠的数据传输。

Effects of a school-based karate intervention on academic achievement,psychosocial functioning,and physical fitness:A multi-country cluster randomized controlled trial

Purpose:To examine the effects of a school-based karate intervention on academic achievement,psychosocial functioning,and physical fitness in children aged 7-8 years.Methods:Twenty schools in 5 different European countries(2 second-grade classrooms per school)participated in a cluster randomized controlled trial(Sport at School trial).Participants were assigned to either a control group,which continued with their habitual physical education lessons,or to an intervention group,which replaced these lessons with a 1-year karate intervention(Karate Mind and Movement program).A total of 721 children(344 girls and 377 boys,7.4±0.5 years old,mean±SD)completed the study,of which 333 and 388 were assigned to the control group and intervention group,respectively.Outcomes included academic performance(average grade),psychosocial functioning(Strengths and Difficulties Questionnaire for parents),and different markers of physical fitness(cardiorespiratory fitness,balance,and flexibility).Results:The intervention provided small but significant benefits compared to the control group for academic achievement(d=0.16;p=0.003),conduct problems(d=-0.28;p=0.003),cardiorespiratory fitness(d=0.36;p<0.001),and balance(d=0.24;p=0.015).There was a trend towards significant benefits for flexibility(d=0.24;p=0.056).No significant benefits were observed for other variables,including psychosocial difficulties,emotional symptoms,hyperactivity/inattention,peer problems,or prosocial behaviour(all p>0.05).Conclusion:A 1-year school-based karate intervention was effective in improving academic achievement,conduct problems,and physical fitness in primary school children.The results support the inclusion of karate during physical education lessons.

A New Method for Deriving High-Vertical-Resolution Wind Vector Data from the L-Band Radar Sounding System in China

High-vertical-resolution radiosonde wind data are highly valuable for describing the dynamics of the meso-and microscale atmosphere. However, the current algorithm used in China's L-band radar sounding system for calculating highvertical-resolution wind vectors excessively smooths the data, resulting in significant underestimation of the calculated kinetic energy of gravity waves compared to similar products from other countries, which greatly limits the effective utilization of the data. To address this issue, this study proposes a novel method to calculate high-vertical-resolution wind vectors that utilizes the elevation angle, azimuth angle, and slant range from L-band radar. In order to obtain wind data with a stable quality, a two-step automatic quality control procedure, including the RMSE-F(root-mean-square error F) test and elemental consistency test are first applied to the slant range data, to eliminate continuous erroneous data caused by unstable signals or radar malfunctions. Then, a wind calculation scheme based on a sliding second-order polynomial fitting is utilized to derive the high-vertical-resolution radiosonde wind vectors. The evaluation results demonstrate that the wind data obtained through the proposed method show a high level of consistency with the high-resolution wind data observed using the Vaisala Global Positioning System and the data observed by the new Beidou Navigation Sounding System. The calculation of the kinetic energy of gravity waves in the recalculated wind data also reaches a level comparable to the Vaisala observations.

Microscopic defects formation and dynamic mechanical response analysis of Q345 steel plate subjected to explosive load

As the basic protective element, steel plate had attracted world-wide attention because of frequent threats of explosive loads. This paper reports the relationships between microscopic defects of Q345 steel plate under the explosive load and its macroscopic dynamics simulation. Firstly, the defect characteristics of the steel plate were investigated by stereoscopic microscope(SM) and scanning electron microscope(SEM). At the macroscopic level, the defect was the formation of cave which was concentrated in the range of 0-3.0 cm from the explosion center, while at the microscopic level, the cavity and void formation were the typical damage characteristics. It also explains that the difference in defect morphology at different positions was the combining results of high temperature and high pressure. Secondly, the variation rules of mechanical properties of steel plate under explosive load were studied. The Arbitrary Lagrange-Euler(ALE) algorithm and multi-material fluid-structure coupling method were used to simulate the explosion process of steel plate. The accuracy of the method was verified by comparing the deformation of the simulation results with the experimental results, the pressure and stress at different positions on the surface of the steel plate were obtained. The simulation results indicated that the critical pressure causing the plate defects may be approximately 2.01 GPa. On this basis, it was found that the variation rules of surface pressure and microscopic defect area of the Q345 steel plate were strikingly similar, and the corresponding mathematical relationship between them was established. Compared with Monomolecular growth fitting models(MGFM) and Logistic fitting models(LFM), the relationship can be better expressed by cubic polynomial fitting model(CPFM). This paper illustrated that the explosive defect characteristics of metal plate at the microscopic level can be explored by analyzing its macroscopic dynamic mechanical response.

Determination of Material Parameters of EVA Foam under Uniaxial Compressive Testing Using Hyperelastic Models

The objective of this research was to determine the mechanical parameter from EVA foam and also investigate its behavior by using Blatz-Ko,Neo-Hookean,Mooney model and experimental test.The physical characteristic of EVA foam was also evaluated by scanning electron microscopy(SEM).The results show that Blatz-Ko and Neo-Hookean model can fit the curve at 5%and 8%strain,respectively.The Mooney model can fit the curve at 50%strain.The modulus of rigidity evaluated from Mooney model is 0.0814±0.0027 MPa.The structure of EVA foam from SEM image shows that EVA structure is a closed cell with homogeneous porous structure.From the result,it is found that Mooney model can adjust the data better than other models.This model can be applied for mechanical response prediction of EVA foam and also for reference value in engineering application.

Comparison of engineering failures and seismic responses of 500 kV transformer-bushing systems in the 2022 Luding earthquake

Cemented and mechanically clamped types of end fittings(fitting-C and fitting-M)are commonly used in transformer bushings.During the Luding Ms 6.8 earthquake that occurred in China on September 5,2022,all transformer bushings with the two types of end fittings in a 500 kV substation were damaged.Post-earthquake field investigations were conducted,and the failures of the two types of bushings were compared.Two elementary simulation models of the transformer-bushing systems were developed to simulate the engineering failures,and further compute their seismic responses for comparison.The results indicate that the hitch lugs of the connection flange are structurally harmful to seismic resistance.Fitting-M can decrease the bending stiffness of the bushing due to the flexible sealing rubber gasket.Since it provides a more flexible connection that dissipates energy,the peak accelerations and relative displacements at the top of the bushing are significantly lower than those of the bushing with fitting-C.Compared with fitting-C,fitting-M transfers the high-stress areas from the connection flange to the root of the porcelain,so the latter becomes the most vulnerable component.Fitting-M increases the failure risk of the low-strength porcelain,indicating the unsuitability of applying it in high-intensity fortification regions.

A statistical analysis of the Kappa-type energy spectrum distribution of radiation belt electrons observed by Van Allen Probes

The energy spectrum of energetic electrons is a key factor representing the dynamic variations of Earth’s Van Allen radiation belts.Increased measurements have indicated that the commonly used Maxwellian and Kappa distributions are inadequate for capturing the realistic spectral distributions of radiation belt electrons.Here we adopt the Kappa-type(KT)distribution as the fitting function and perform a statistical analysis to investigate the radiation belt electron flux spectra observed by the Van Allen Probes.By calculating the optimal values of the key KT distribution parameters(i.e.,κandθ2)from the observed spectral shapes,we fit the radiation belt electron fluxes at different L-shells under different geomagnetic conditions.In this manner,we obtain typical values of the KT distribution parameters,which are statistically feasible for modeling the radiation belt electron flux profiles during either geomagnetically quiet or active periods.A comparison of the KT distribution model results with those using the Maxwellian or Kappa distribution reveals the advantage of the KT distribution for studying the overall properties of the radiation belt electron spectral distribution,which has important implications for deepening the current understanding of the radiation belt electron dynamics under evolving geomagnetic conditions.

Resistance development,cross-resistance,and fitness costs associated with Aphis gossypii resistance towards sulfoxaflor and acetamiprid in different geographical regions

Aphis gossypii has become increasingly difficult to manage due to its strong insecticide resistance.In the laboratory,we established sulfoxaflor-resistant and acetamiprid-resistant strains in two A.gossypii populations with different basal insecticide resistance levels,and evaluated the effects of basal insecticide resistance on the resistance development and cross-resistance,as well as differences in fitness.Under the same selection pressure,Yarkant A.gossypii(with low basal insecticide resistance)evolved resistance to sulfoxaflor and acetamiprid more quickly than Jinghe A.gossypii(with high basal insecticide resistance),and the evolution of A.gossypii resistance to sulfoxaflor developed faster than acetamiprid in both Yarkant and Jinghe,Xingjiang,China.The sulfoxaflor-resistant strains selected from Yarkant and Jinghe developed significant cross-resistance to acetamiprid,imidacloprid,thiamethoxam and pymetrozine;while the acetamiprid-resistant strains developed significant cross-resistance to sulfoxaflor,imidacloprid,thiamethoxam,pymetrozine,and chlorpyrifos.The relative fitness of A.gossypii decreased as the resistance to sulfoxaflor and acetamiprid developed.The relative fitness levels of the sulfoxaflor-resistant strains(Yarkant-SulR and Jinghe-SulR)were lower than those of the acetamipridresistant strains(Yarkant-AceR and Jinghe-AceR).In addition,the relative fitness levels of sulfoxaflor-and acetamiprid-resistant strains were lower in Jinghe than in Yarkant.In summary,basal insecticide resistance of A.gossypii and insecticide type affected the evolution of resistance to insecticides in A.gossypii,as well as cross-resistance to other insecticides.The sulfoxaflor-and acetamiprid-resistant A.gossypii strains had obvious fitness costs.The results of this work will contribute to the insecticide resistance management and integrated management of A.gossypii.

Associations between health-related fitness and patient-reported symptoms in newly diagnosed breast cancer patients

Background:Newly diagnosed breast cancer patients experience symptoms that may affect their quality of life,treatment outcomes,and survival.Preventing and managing breast cancer-related symptoms soon after diagnosis is essential.The purpose of this study was to investigate the associations between health-related fitness(HRF)and patient-reported symptoms in newly diagnosed breast cancer patients.Methods:This study utilized baseline data from the Alberta Moving Beyond Breast Cancer Cohort Study that were collected within 90 days of diagnosis.HRF measures included peak cardiopulmonary fitness(peak volume of oxygen consumption(VO_(2peak))),maximal muscular strength and endurance,flexibility,and body composition.Symptom measures included depression,sleep quality,and fatigue.Adjusted multivariable logistic regression was performed for analyses.Results:Of 1458 participants,51.5%reported poor sleep quality,26.5%reported significant fatigue,and 10.4%reported moderate depression.In multivariable-adjusted models,lower relative VO_(2peak)was independently associated with a greater likelihood of all symptom measures,including moderate depression(p<0.001),poor sleep quality(p=0.009),significant fatigue(p=0.008),any symptom(p<0.001),and multiple symptoms(p<0.001).VO_(2peak)demonstrated threshold associations with all symptom measures such that all 3 lower quartiles exhibited similar elevated risk compared to the highest quartile.The strength of the threshold associations varied by the symptom measure with odds ratios ranging from-1.5 for poor sleep quality to-3.0 for moderate depression and multiple symptoms.Moreover,lower relative upper body muscular endurance was also independently associated with fatigue in a dose-response manner(p=0.001),and higher body weight was independently associated with poor sleep quality in an inverted U pattern(p=0.021).Conclusion:Relative VO_(2peak)appears to be a critical HRF component associated with multiple patient-reported symptoms in newly diagnosed breast cancer patients.Other HRF parameters may also be important for specific symptoms.Exercise interventions targeting different HRF components may help newly diagnosed breast cancer patients manage specific symptoms and improve outcomes.

Association between baseline levels of muscular strength and risk of stroke in later life:The Cooper Center Longitudinal Study

Background:Muscular strength is an important component of physical fitness.We evaluated the relationship between baseline muscular strength and risk of stroke among adults who were aged≥65 years during follow-up.Methods:We included 7627 healthy adults(mean age=43.9 years,86.0%male)underwent a baseline physical examination between 1980 and 1989.Muscular strength was determined by 1-repetition maximum measures for bench press and leg press and categorized into age-and sex-specific tertiles for each measure.Cardiorespiratory fitness(CRF)was assessed via a maximal treadmill exercise test.Those enrolled in fee-for-service Medicare from 1999 to 2019 were included in the analyses.Associations between baseline strength and stroke outcomes were estimated using a modified Cox proportional hazards model.In a secondary analysis,we examined stroke risk by categories of CRF where Quintile 1=low,Quintiles 2-3=moderate,and Quintiles 4-5=high CRF based on age and sex.Results:After 70,072 person-years of Medicare follow-up,there were 1211 earliest indications of incident stroke.In multivariable analyses,the hazard ratio(95%confidence interval(95%CI))for stroke across bench press categories were 1.0(referent),0.96(0.83-1.11),and 0.89(0.77-1.04),respectively(p trend=0.14).The trend across categories of leg press was also non-significant(p trend=0.79).Adjusted hazard ratio(95%CI)for stroke across ordered CRF categories were 1.0(referent),0.90(0.71-1.13),and 0.72(0.57-0.92)(p trend<0.01).Conclusion:While meeting public health guidelines for muscular strengthening activities is likely to improve muscular strength as well as many health outcomes in older adults,performing such activities may not be helpful in preventing stroke.Conversely,meeting guidelines for aerobic activity is likely to improve CRF and lower stroke risk.

Development,validation,and transportability of several machine-learned,non-exercise-based VO_(2max)prediction models for older adults

Background:There exist few maximal oxygen uptake(VO_(2max))non-exercise-based prediction equations,fewer using machine learning(ML),and none specifically for older adults.Since direct measurement of VO_(2max)is infeasible in large epidemiologic cohort studies,we sought to develop,validate,compare,and assess the transportability of several ML VO_(2max)prediction algorithms.Methods:The Baltimore Longitudinal Study of Aging(BLSA)participants with valid VO2_(max)tests were included(n=1080).Least absolute shrinkage and selection operator,linear-and tree-boosted extreme gradient boosting,random forest,and support vector machine(SVM)algorithms were trained to predict VO_(2max)values.We developed these algorithms for:(a)the overall BLSA,(b)by sex,(c)using all BLSA variables,and(d)variables common in aging cohorts.Finally,we quantified the associations between measured and predicted VO_(2max)and mortality.Results:The age was 69.0±10.4 years(mean±SD)and the measured VO_(2max)was 21.6±5.9 mL/kg/min.Least absolute shrinkage and selection operator,linear-and tree-boosted extreme gradient boosting,random forest,and support vector machine yielded root mean squared errors of 3.4 mL/kg/min,3.6 mL/kg/min,3.4 mL/kg/min,3.6 mL/kg/min,and 3.5 mL/kg/min,respectively.Incremental quartiles of measured VO_(2max)showed an inverse gradient in mortality risk.Predicted VO_(2max)variables yielded similar effect estimates but were not robust to adjustment.Conclusion:Measured VO_(2max)is a strong predictor of mortality.Using ML can improve the accuracy of prediction as compared to simpler approaches but estimates of association with mortality remain sensitive to adjustment.Future studies should seek to reproduce these results so that VO_(2max),an important vital sign,can be more broadly studied as a modifiable target for promoting functional resiliency and healthy aging.