The learning algorithms of causal discovery mainly include score-based methods and genetic algorithms(GA).The score-based algorithms are prone to searching space explosion.Classical GA is slow to converge,and prone to...The learning algorithms of causal discovery mainly include score-based methods and genetic algorithms(GA).The score-based algorithms are prone to searching space explosion.Classical GA is slow to converge,and prone to falling into local optima.To address these issues,an improved GA with domain knowledge(IGADK)is proposed.Firstly,domain knowledge is incorporated into the learning process of causality to construct a new fitness function.Secondly,a dynamical mutation operator is introduced in the algorithm to accelerate the convergence rate.Finally,an experiment is conducted on simulation data,which compares the classical GA with IGADK with domain knowledge of varying accuracy.The IGADK can greatly reduce the number of iterations,populations,and samples required for learning,which illustrates the efficiency and effectiveness of the proposed algorithm.展开更多
Background The pink bollworm,Pectinophora gossypiella(Saunders),is a devastating global pest of cotton that has caused substantial economic damage to Bt Bollgard-Ⅱ~?cotton plants in recent years due to the evolution ...Background The pink bollworm,Pectinophora gossypiella(Saunders),is a devastating global pest of cotton that has caused substantial economic damage to Bt Bollgard-Ⅱ~?cotton plants in recent years due to the evolution of Bt resistance.The associated fitness cost is assumed to be one of the factors delaying the development of resistance against Bt transgenic crops.Hence,the present study was undertaken to assess the biological performance of pink bollworms by comparing the life history and demographic parameters of a resistant(Field-R)and susceptible(Lab-S)population.Results Prolonged larval duration(23.40 days in Field-R vs 18.80 days in Lab-S population),total life cycle(male=50.00 vs 42.80 days;female=53.60 vs 46.20 days),reduced fecundity(100.60 vs 154.20 eggs/female)and fertility(88.00 vs 138.00 fertile eggs/female)was observed.The demographic parameters indicated a significant reduction in the net reproductive rate(184.27 vs 276.72),innate capacity for increase in number(0.11 vs 0.15),finite rate of increase in number(1.12 vs 1.16 female progenies produced/female/day),weekly multiplication rate(2.16 vs 2.86),potential fecundity(545.06 vs 634.11 eggs),number of hypothetical F_2 females(33955.65 vs 76572.41),but longer mean length of generation(47.54 vs 37.74 days)and population doubling time(6.30 vs 4.62 days)in Field-R compared with Lab-S population.A stage-specific life to ble demonstrated the differences in survival rates between susceptible and resistant populations at various life stages,with the resistant population having higher generation mortality(0.22vs 0.19).Conclusions The study confirms the involvement of fitness costs associated with Bt resistance in P.gossypiella.Despite reduced reproductive fitness,the resistant population tried prolonging the larval stage as a compensatory mechanism to repair the damaged host tissues due to Bt intoxication and for accumulation of enough nutrient reserves for normal pupation and adult emergence.Presence of a high proportion of double Bt-resistant larvae in the field coupled with continued noncompliance with refug planting certainly favours the flaring up of this monophagous pest despite the observed fitness costs.The resistance cannot be effectively reversed unless suitable alternative management strategies are deployed.展开更多
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 unde...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.展开更多
To analyze the influence of time synchronization error,phase synchronization error,frequency synchronization error,internal delay of the transceiver system,and range error and angle error between the unit radars on th...To analyze the influence of time synchronization error,phase synchronization error,frequency synchronization error,internal delay of the transceiver system,and range error and angle error between the unit radars on the target detection performance,firstly,a spatial detection model of distributed high-frequency surface wave radar(distributed-HFSWR)is established in this paper.In this model,a method for accurate extraction of direct wave spectrum based on curve fitting is proposed to obtain accurate system internal delay and frequency synchronization error under complex electromagnetic environment background and low signal to noise ratio(SNR),and to compensate for the shift of range and Doppler frequency caused by time-frequency synchronization error.The direct wave component is extracted from the spectrum,the range estimation error and Doppler estimation error are reduced by the method of curve fitting,and the fitting accuracy of the parameters is improved.Then,the influence of frequency synchronization error on target range and radial Doppler velocity is quantitatively analyzed.The relationship between frequency synchronization error and radial Doppler velocity shift and range shift is given.Finally,the system synchronization parameters of the trial distributed-HFSWR are obtained by the proposed spectrum extraction method based on curve fitting,the experimental data is compensated to correct the shift of the target,and finally the correct target parameter information is obtained.Simulations and experimental results demonstrate the superiority and correctness of the proposed method,theoretical derivation and detection model proposed in this paper.展开更多
This work introduces a novel method for measuring thin film thickness,employing a multi-wavelength method that significantly reduces the need for broad-spectrum data.Unlike traditional techniques that require sev⁃eral...This work introduces a novel method for measuring thin film thickness,employing a multi-wavelength method that significantly reduces the need for broad-spectrum data.Unlike traditional techniques that require sev⁃eral hundred spectral data points,the multi-wavelength method achieves precise thickness measurements with data from only 10 wavelengths.This innovation not only simplifies the process of spectral measurement analysis but also enables accurate real-time thickness measurement on industrial coating production lines.The method effectively reconstructs and fits the visible spectrum(400-800 nm)using a minimal amount of data,while maintaining measurement error within 7.1%.This advancement lays the foundation for more practical and efficient thin film thickness determination techniques in various industrial applications.展开更多
基于锻炼心理学领域中的"从无活动到保持活动的4步骤模型"(Four Steps from In-activity to Activity;FIT模型),以3 807名大学生为研究对象,探讨了大学生身体活动阶段变化与健康状况变量(身体体质、主观良好感、健康满意度和...基于锻炼心理学领域中的"从无活动到保持活动的4步骤模型"(Four Steps from In-activity to Activity;FIT模型),以3 807名大学生为研究对象,探讨了大学生身体活动阶段变化与健康状况变量(身体体质、主观良好感、健康满意度和不适感)之间的关系。研究结果表明,处于活动阶段的个体,其健康状况水平均好于处于不活动阶段的个体;在3个活动阶段上,处于保持期(即长期保持规律性身体活动)的个体,其健康状况水平均好于处于探索期和波动期的个体;人口统计学变量和健康状况变量共同解释了17.6%的阶段方差变异(F=108.48,P<0.05)。验证了FIT模型中大学生身体活动阶段变化与健康状况之间的相关关系,为今后运用FIT模型诊断大学生身体活动变化阶段及其相应健康状况提供了实证依据。展开更多
本文基于锻炼心理学领域中的"从无活动到保持活动的四步骤模型"(Four Steps from Inactivity to Activity;FIT模型),以3807名大学生为研究对象,考察了大学生身体活动变化阶段与各阶段对应的每周能耗量之间的关系。研究结果表...本文基于锻炼心理学领域中的"从无活动到保持活动的四步骤模型"(Four Steps from Inactivity to Activity;FIT模型),以3807名大学生为研究对象,考察了大学生身体活动变化阶段与各阶段对应的每周能耗量之间的关系。研究结果表明:(1)大学生各阶段平均每周身体活动能耗量依次为:前考虑期188.30千卡、考虑期319.30千卡、准备期586.84千卡、波动期1270.73千卡、探索期1604.44千卡和保持期1862.59千卡。变化阶段与能耗的相关性有统计学意义(r=0.627,P<0.001)。(2)不同阶段、不同年级大学生的每周身体活动能耗量存在显著性差异。低年级大学生在考虑期、准备期和波动期的每周能耗量均显著高于高年级,男大学生在保持期和波动期的每周能耗量均显著高于女大学生。(3)每两个相邻阶段的能耗量均有显著性差异,且前考虑期、考虑期和准备期三个不活动阶段的每周身体活动能耗水平均显著小于800千卡(世界卫生组织欧洲地区身体活动推荐最低标准)。波动期、探索期和保持期三个活动阶段的每周身体活动能耗水平均显著大于800千卡。本研究验证了身体活动变化阶段与每周能耗量的对应关系,为考察FIT模型身体活动阶段测量的效度提供了初步的实证性支持。展开更多
从无活动到保持活动的四步骤模型(Four Steps from Inactivity to Activity,FIT模型)将个体的身体活动变化过程划分为六个阶段:前考虑期,考虑期,准备期,探索期,波动期和保持期。其中前三个阶段为不活动期,后三个阶段为活动期。本研究基...从无活动到保持活动的四步骤模型(Four Steps from Inactivity to Activity,FIT模型)将个体的身体活动变化过程划分为六个阶段:前考虑期,考虑期,准备期,探索期,波动期和保持期。其中前三个阶段为不活动期,后三个阶段为活动期。本研究基于FIT模型,采用横断性研究设计,考查了1206名成年人(27～55岁)身体活动变化阶段与健康变量(身体体质、积极/消极主观良好感、健康满意度、不适感和BMI)之间的关系。研究结果表明,除BMI之外,健康变量在身体活动变化阶段上的主效应均显著,处于活动阶段的个体健康水平均好于处于不活动阶段的个体;处于保持期(即长期保持规律性身体活动)的个体身体体质、积极主观良好感和健康满意度水平均高于探索期和波动期,其消极主观良好感和身体不适感均低于探索期和波动期。此外,性别、年龄和教育程度不同程度调节了变化阶段与健康变量之间的关系。本研究验证了FIT模型中成年人身体活动变化阶段与健康变量之间的相关关系,为今后运用FIT模型诊断成年人身体活动变化阶段及其相应健康状况提供了实证性依据。展开更多
基金supported by the National Social Science Fund of China(2022-SKJJ-B-084).
文摘The learning algorithms of causal discovery mainly include score-based methods and genetic algorithms(GA).The score-based algorithms are prone to searching space explosion.Classical GA is slow to converge,and prone to falling into local optima.To address these issues,an improved GA with domain knowledge(IGADK)is proposed.Firstly,domain knowledge is incorporated into the learning process of causality to construct a new fitness function.Secondly,a dynamical mutation operator is introduced in the algorithm to accelerate the convergence rate.Finally,an experiment is conducted on simulation data,which compares the classical GA with IGADK with domain knowledge of varying accuracy.The IGADK can greatly reduce the number of iterations,populations,and samples required for learning,which illustrates the efficiency and effectiveness of the proposed algorithm.
基金the award of the DST-INSPIRE fellowship(IF190948)by the Department of Science and Technology,Government of India。
文摘Background The pink bollworm,Pectinophora gossypiella(Saunders),is a devastating global pest of cotton that has caused substantial economic damage to Bt Bollgard-Ⅱ~?cotton plants in recent years due to the evolution of Bt resistance.The associated fitness cost is assumed to be one of the factors delaying the development of resistance against Bt transgenic crops.Hence,the present study was undertaken to assess the biological performance of pink bollworms by comparing the life history and demographic parameters of a resistant(Field-R)and susceptible(Lab-S)population.Results Prolonged larval duration(23.40 days in Field-R vs 18.80 days in Lab-S population),total life cycle(male=50.00 vs 42.80 days;female=53.60 vs 46.20 days),reduced fecundity(100.60 vs 154.20 eggs/female)and fertility(88.00 vs 138.00 fertile eggs/female)was observed.The demographic parameters indicated a significant reduction in the net reproductive rate(184.27 vs 276.72),innate capacity for increase in number(0.11 vs 0.15),finite rate of increase in number(1.12 vs 1.16 female progenies produced/female/day),weekly multiplication rate(2.16 vs 2.86),potential fecundity(545.06 vs 634.11 eggs),number of hypothetical F_2 females(33955.65 vs 76572.41),but longer mean length of generation(47.54 vs 37.74 days)and population doubling time(6.30 vs 4.62 days)in Field-R compared with Lab-S population.A stage-specific life to ble demonstrated the differences in survival rates between susceptible and resistant populations at various life stages,with the resistant population having higher generation mortality(0.22vs 0.19).Conclusions The study confirms the involvement of fitness costs associated with Bt resistance in P.gossypiella.Despite reduced reproductive fitness,the resistant population tried prolonging the larval stage as a compensatory mechanism to repair the damaged host tissues due to Bt intoxication and for accumulation of enough nutrient reserves for normal pupation and adult emergence.Presence of a high proportion of double Bt-resistant larvae in the field coupled with continued noncompliance with refug planting certainly favours the flaring up of this monophagous pest despite the observed fitness costs.The resistance cannot be effectively reversed unless suitable alternative management strategies are deployed.
基金Science and Technology Project of Fire Rescue Bureau of Ministry of Emergency Management(Grant No.2022XFZD05)S&T Program of Hebei(Grant No.22375419D)National Natural Science Foundation of China(Grant No.11802160).
文摘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.
基金supported by the National Natural Science Foundation of China(61701140).
文摘To analyze the influence of time synchronization error,phase synchronization error,frequency synchronization error,internal delay of the transceiver system,and range error and angle error between the unit radars on the target detection performance,firstly,a spatial detection model of distributed high-frequency surface wave radar(distributed-HFSWR)is established in this paper.In this model,a method for accurate extraction of direct wave spectrum based on curve fitting is proposed to obtain accurate system internal delay and frequency synchronization error under complex electromagnetic environment background and low signal to noise ratio(SNR),and to compensate for the shift of range and Doppler frequency caused by time-frequency synchronization error.The direct wave component is extracted from the spectrum,the range estimation error and Doppler estimation error are reduced by the method of curve fitting,and the fitting accuracy of the parameters is improved.Then,the influence of frequency synchronization error on target range and radial Doppler velocity is quantitatively analyzed.The relationship between frequency synchronization error and radial Doppler velocity shift and range shift is given.Finally,the system synchronization parameters of the trial distributed-HFSWR are obtained by the proposed spectrum extraction method based on curve fitting,the experimental data is compensated to correct the shift of the target,and finally the correct target parameter information is obtained.Simulations and experimental results demonstrate the superiority and correctness of the proposed method,theoretical derivation and detection model proposed in this paper.
基金Supported by National Key R&D Program of China(2021YFA0715500)National Natural Science Foundation of China(NSFC)(12227901)+2 种基金Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB0580000)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Chinese Academy of Sciences President's International Fellowship Initiative(2021PT0007).
文摘This work introduces a novel method for measuring thin film thickness,employing a multi-wavelength method that significantly reduces the need for broad-spectrum data.Unlike traditional techniques that require sev⁃eral hundred spectral data points,the multi-wavelength method achieves precise thickness measurements with data from only 10 wavelengths.This innovation not only simplifies the process of spectral measurement analysis but also enables accurate real-time thickness measurement on industrial coating production lines.The method effectively reconstructs and fits the visible spectrum(400-800 nm)using a minimal amount of data,while maintaining measurement error within 7.1%.This advancement lays the foundation for more practical and efficient thin film thickness determination techniques in various industrial applications.
文摘基于锻炼心理学领域中的"从无活动到保持活动的4步骤模型"(Four Steps from In-activity to Activity;FIT模型),以3 807名大学生为研究对象,探讨了大学生身体活动阶段变化与健康状况变量(身体体质、主观良好感、健康满意度和不适感)之间的关系。研究结果表明,处于活动阶段的个体,其健康状况水平均好于处于不活动阶段的个体;在3个活动阶段上,处于保持期(即长期保持规律性身体活动)的个体,其健康状况水平均好于处于探索期和波动期的个体;人口统计学变量和健康状况变量共同解释了17.6%的阶段方差变异(F=108.48,P<0.05)。验证了FIT模型中大学生身体活动阶段变化与健康状况之间的相关关系,为今后运用FIT模型诊断大学生身体活动变化阶段及其相应健康状况提供了实证依据。
文摘本文基于锻炼心理学领域中的"从无活动到保持活动的四步骤模型"(Four Steps from Inactivity to Activity;FIT模型),以3807名大学生为研究对象,考察了大学生身体活动变化阶段与各阶段对应的每周能耗量之间的关系。研究结果表明:(1)大学生各阶段平均每周身体活动能耗量依次为:前考虑期188.30千卡、考虑期319.30千卡、准备期586.84千卡、波动期1270.73千卡、探索期1604.44千卡和保持期1862.59千卡。变化阶段与能耗的相关性有统计学意义(r=0.627,P<0.001)。(2)不同阶段、不同年级大学生的每周身体活动能耗量存在显著性差异。低年级大学生在考虑期、准备期和波动期的每周能耗量均显著高于高年级,男大学生在保持期和波动期的每周能耗量均显著高于女大学生。(3)每两个相邻阶段的能耗量均有显著性差异,且前考虑期、考虑期和准备期三个不活动阶段的每周身体活动能耗水平均显著小于800千卡(世界卫生组织欧洲地区身体活动推荐最低标准)。波动期、探索期和保持期三个活动阶段的每周身体活动能耗水平均显著大于800千卡。本研究验证了身体活动变化阶段与每周能耗量的对应关系,为考察FIT模型身体活动阶段测量的效度提供了初步的实证性支持。
文摘从无活动到保持活动的四步骤模型(Four Steps from Inactivity to Activity,FIT模型)将个体的身体活动变化过程划分为六个阶段:前考虑期,考虑期,准备期,探索期,波动期和保持期。其中前三个阶段为不活动期,后三个阶段为活动期。本研究基于FIT模型,采用横断性研究设计,考查了1206名成年人(27～55岁)身体活动变化阶段与健康变量(身体体质、积极/消极主观良好感、健康满意度、不适感和BMI)之间的关系。研究结果表明,除BMI之外,健康变量在身体活动变化阶段上的主效应均显著,处于活动阶段的个体健康水平均好于处于不活动阶段的个体;处于保持期(即长期保持规律性身体活动)的个体身体体质、积极主观良好感和健康满意度水平均高于探索期和波动期,其消极主观良好感和身体不适感均低于探索期和波动期。此外,性别、年龄和教育程度不同程度调节了变化阶段与健康变量之间的关系。本研究验证了FIT模型中成年人身体活动变化阶段与健康变量之间的相关关系,为今后运用FIT模型诊断成年人身体活动变化阶段及其相应健康状况提供了实证性依据。
