By focusing on the vulnerability of the structure of marine equipments, together with considering the randomness of meta-ocean load in statistics, a kind of analytical method of fatigue characteristics of marine struc...By focusing on the vulnerability of the structure of marine equipments, together with considering the randomness of meta-ocean load in statistics, a kind of analytical method of fatigue characteristics of marine structure based on full- scale and actual measurement of prototype is proposed. On the basis of short-term field measurement results of structural response, research is carried out on the fatigue analysis of hinge joints at the upper part of the Soft Yoke single point Mooring System (SYMS) by simultaneously monitoring the environmental load and considering the design criteria of offshore structure. Through analysis of finite element modeling, the time-histories of typical stress response are obtained, and then the assessment of fatigue damage at key hinge joints is conducted. The simulation results indicate that the proposed method can accurately analyze the fatigue damage of offshore engineering structure caused by the effect of wave load. The present analytical method of fatigue characteristics can be extended on other offshore engineering structures subjected to meta-ocean load.展开更多
Background: Self-efficacy has been identified as an important determinant of youth's behavior change including physical activity(PA) participation. However, the dimensionality check of a PA self-efficacy scale has...Background: Self-efficacy has been identified as an important determinant of youth's behavior change including physical activity(PA) participation. However, the dimensionality check of a PA self-efficacy scale has rarely been conducted in China. The current study aims to examine(1) the unidimensionality of a shortened Chinese version of PA self-efficacy scale(S-PASESC);(2) the measurement invariance of S-PASESC across gender and levels of education;(3) the latent factor mean difference between gender and levels of education;(4) the direct effects of self-efficacy on PA by different gender and education levels; and(5) the comparisons of the direct effects of self-efficacy on PA across gender and education levels.Methods: The participants were 5 th through 11 th grade public school students recruited from 7 cities located in different geographic regions of China. The final data include a total of 3003 participants(49.7% boys) who have completed the scales.Results: Confirmatory factor analysis(CFA) test supported the unidimensionality of S-PASESC. The S-PASESC is invariant across gender and 3 levels of education at both configural, full metric, and full scalar levels. Findings from latent mean comparisons showed that boys reported higher PA self-efficacy than girls. Students' perceived PA self-efficacy tend to decrease from elementary to high school. Finally, self-efficacy positively related to PA by groups of different gender and education levels and the relationship between self-efficacy and PA is stronger among middle school boys than girls.Conclusion: Findings suggest S-PASESC is a valid scale for measuring Chinese students' PA self-efficacy.展开更多
Utilization of wind energy is a promising way to generate power,and wind turbine blades play a key role in collecting the wind energy effectively.This paper attempts to measure the deformation parameter of wind turbin...Utilization of wind energy is a promising way to generate power,and wind turbine blades play a key role in collecting the wind energy effectively.This paper attempts to measure the deformation parameter of wind turbine blades in mechanics experiments using a videometric method. In view that the blades experience small buckling deformation and large integral deformation simultaneously, we proposed a parallel network measurement(PNM) method including the key techniques such as camera network construction,camera calibration,distortion correction,the semi-automatic high-precision extraction of targets,coordinate systems unification,and bundle adjustment,etc. The relatively convenient construction method of the measuring system can provide an abundant measuring content,a wide measuring range and post processing.The experimental results show that the accuracy of the integral deformation measurement is higher than 0.5 mm and that of the buckling deformation measurement higher than 0.1mm.展开更多
In the terahertz band,the dispersive characteristic of dielectric material is one of the major problems in the scaled radar cross section(RCS)measurement,which is inconsistent with the electrodynamics similitude deduc...In the terahertz band,the dispersive characteristic of dielectric material is one of the major problems in the scaled radar cross section(RCS)measurement,which is inconsistent with the electrodynamics similitude deducted according to the Maxwell’s equations.Based on the high-frequency estimation method of physical optics(PO),a scaled RCS measurement method for lossy objects is proposed through dynamically matching the reflection coefficients according to the distribution of the object facets.Simulations of the model of SLICY are conducted,and the inversed RCS of the lossy prototype is obtained using the proposed method.Comparing the inversed RCS with the calculated results,the validity of the proposed method is demonstrated.The proposed method provides an effective solution to the scaled RCS measurement for lossy objects in the THz band.展开更多
Background: Bonding disorders affect the growth and development of infants. In Japan, the Japanese version of the Mother-to-Infant Bonding Scale (MIBS-J) is widely used for early detection of bonding disorders. Repeat...Background: Bonding disorders affect the growth and development of infants. In Japan, the Japanese version of the Mother-to-Infant Bonding Scale (MIBS-J) is widely used for early detection of bonding disorders. Repeated use of a questionnaire has problems of reduced validity. In order to correctly detect bonding disorders at multiple time points, it is necessary to confirm the measurement invariance of the scale. Baba et al. reported that invariance of the MIBS-J factor structure could only be obtained by abridging the scale into three items. Purpose: The aim of this study was to 1) confirm the factor structure and measurement invariance of the MIBS-J between two measurement times and 2) to examine factors that can be used without being affected by measurement time in order to identify item that contribute to measure met invariance. Methods: We analysed the data of 1049 and 878 mothers with a neonate collected in two waves: 5 days (Wave 1) and 1 month postpartum (Wave 2). Exploratory and confirmatory factor analyses were conducted on the data randomly divided into two groups in each wave. Results: The three-item model (MIBS-J items 1, 6, and 8) was most accepted. Measurement invariance and structural invariance were confirmed in the model. This was consistent with Baba et al.’s model. Conclusion: The three MIBS-J items showed measurement invariance and structural invariance in Japanese mothers during 1 month postpartum.展开更多
In this paper, we presented a method of using the l as er scanning triangulation for the non-contact 3D surface profile measurement of large-scale object. The characteristic of large-scale object non-contact mea surem...In this paper, we presented a method of using the l as er scanning triangulation for the non-contact 3D surface profile measurement of large-scale object. The characteristic of large-scale object non-contact mea surement is analyzed and the measuring method is proposed. Main factors influenc ing measurement precision such as image distortion and accurate designation of s peckle center are analyzed and methods of solving these problems are proposed. W e designed a combined filter by which the pulse noise and the Gaussian noise of speckle image can be eliminated efficiently. Using the characteristic of intensi ty distribution of laser speckle image we proposed a new approximating method th at could locate the center of laser speckle image at sub-pixel. The auxiliary v ariables are set to linearize the relationship between the image displacement an d the distance, the accurate values of laser triangulation system parameters cou ld be calibrated accurately and the measuring precision is increased remarkabl y. Using the above techniques we designed a measuring system based on laser sc anning triangulation. The results of the experiment show that these methods can raise the measuring precision of large-scale 3D surface profile effectively.展开更多
Spatial angle measurement, especially the measurement of horizontal and vertical angle, is a basic method used for industrial large-scale coordinate measurement. As main equipments in use, both theodolites and laser t...Spatial angle measurement, especially the measurement of horizontal and vertical angle, is a basic method used for industrial large-scale coordinate measurement. As main equipments in use, both theodolites and laser trackers can provide very high accuracy for spatial angle measurement. However, their industrial applications are limited by low level of automation and poor parallelism. For the purpose of improving measurement efficiency, a lot of studies have been conducted and several alternative methods have been proposed. Unfortunately, all these means are either low precision or too expensive. In this paper, a novel method of spatial angle measurement based on two rotating planar laser beams is proposed and demonstrated. Photoelectric receivers placed on measured points are used to receive the rotating planner laser signals transmitted by laser transmitters. The scanning time intervals of laser planes were measured, and then measured point's horizontal/vertical angles can be calculated. Laser plane's angle parameters are utilized to establish the abstract geometric model of transmitter. Calculating formulas of receiver's horizontal/vertical angles have been derived. Measurement equations' solvability conditions and judgment method of imaginary solutions are also presented after analyzing. Proposed method for spatial angle measurement is experimentally verified through a platform consisting of one laser transmitter and one optical receiver. The transmitters used in new method are only responsible for providing rotating light plane signals carrying angle information. Receivers automatically measure scanning time of laser planes and upload data to the workstation to calculate horizontal angle and vertical angle. Simultaneous measurement of multiple receivers can be realized since there is no human intervention in measurement process .Spatial angle measurement result indicates that the repeatable accuracy of new method is better than 10". Proposed method can improve measurement's automation degree and speed while ensuring measurement accuracy.展开更多
The global exponentially stability was studied for time-delay and time-varying measure large scale systems with impulsive effects. Firstly, the concepts are drawn for the functional category. Secondly, some sufficient...The global exponentially stability was studied for time-delay and time-varying measure large scale systems with impulsive effects. Firstly, the concepts are drawn for the functional category. Secondly, some sufficient conditions of the uniformly stability and the global exponentially stability are given for the above systems through defining a Lyapunov function of the weighting sum of the variable absolute by using the Lyapunov function method and the comparison principle. At the same time, the new conclusion of stability of these systems is more universal and contains the existing results. Finally, an example is given to illustrate the feasibility and validity of the obtained results.展开更多
Remote sensing and on-site measurement are used to determine the heat environment within a community,and are compared the differences for heat analysis. The two methods perform differently for various underlying surfa...Remote sensing and on-site measurement are used to determine the heat environment within a community,and are compared the differences for heat analysis. The two methods perform differently for various underlying surfaces. The individual methods can detect different aspects of the heat environment,which used in combination are useful for heat island research. The differences in estimated air and surface temperatures are smaller in open space and more obvious for vegetated surfaces. Ventilation does not affect the difference between air and surface temperature in open areas,and the vegetation surface and shading moderates surface temperature more effectively than the water surface; The forest is a type of underlying surface with heat comfortable,in which the feeling of air temperature is much difference to the structure of heat environment that should be survey and detected separately. The two methods can be used to study different aspects of the heat environment,thus forming a comprehensive approach for planners in urban and rural spaces.展开更多
The study examined the measurement invariance (configural,metric,scalar,and error variances) and factor mean scores equivalencies of a modified version of the Strengths and Weaknesses of ADHDSymptoms and Normal Behavi...The study examined the measurement invariance (configural,metric,scalar,and error variances) and factor mean scores equivalencies of a modified version of the Strengths and Weaknesses of ADHDSymptoms and Normal Behavior Scale (SWAN-M) across ratings provided by mothers of clinic-referred children and adolescents,diagnosed with (N = 666) and without (N = 202) ADHD. Confirmatory factor analysis (CFA) of these ratings provided support for the bi-factor model of ADHD [orthogonal general and specific factors for inattention (IA) and hyperactivity/impulsivity (HI) symptoms]. Multiple-group confirmatory factor analysis (CFA) of the bi-factor model supported full measurement invariance. Findings also showed that for latent mean scores,the ADHD group had higher scores than the non-ADHD group for the ADHD general and IA specific factors. The findings indicate that observed scores (based on maternal ratings of the SWAN-M) are comparable,as they have the same measurement properties. The theoretical,psychometric and clinical implications of the findings are discussed.展开更多
Objective To explore the possibility of diagnosis types of acute stroke, elevating treatment quality and promoting prognosis with acute stroke clinical measuring scale . Methods To gain a measuring scale formula and s...Objective To explore the possibility of diagnosis types of acute stroke, elevating treatment quality and promoting prognosis with acute stroke clinical measuring scale . Methods To gain a measuring scale formula and simplify this formula after stepwise regression Fisher distinguish analysis to 18 clinical variable of 184 acute stroke patients and to validate its sensitivity, specificity and positive foretell value to diagnosis of acute stroke. Results We gained scale that Y=0.617×action+0.485×BP+1.241×headache+0.74×vomiting+0.955×cervical resistance-1.215×TIA-0.727×heart disease-2.78;sensitivity of this formula to diagnosis of cerebral infarction and cerebral hemorrhage was 90.5%and 70%respectively,its specificity was 70%and 90.5%respectively,positive foretell value was 71.7%and 89.7%(Y≥0 means cerebral hemorrhage,Y<0 means cerebral infarction). Simple formula is S=0.5×action+0.5×BP+1×headache+1×vomiting+1×cervical resistance-1×TIA-1×hear disease-3;its sensitivity was 89.3%and 68%,specificity was 68%and 89.3%,positive foretell value was 70.1%and 88.3%.There was no apparent difference in sensitivity; specificity and positive foretell value between two formulas. Conclusion Acute stroke clinical measuring scale can help early diagnosis, treatment and rehabilitation of cerebral stroke patients.展开更多
The Coriolis force method is a recently developed and highly regarded direct measurement technique that enables high-precision measurement of bulk materials.The operational parameters and variations thereof directly i...The Coriolis force method is a recently developed and highly regarded direct measurement technique that enables high-precision measurement of bulk materials.The operational parameters and variations thereof directly influence the measurement accuracy of the equipment.In this study,a measurement correction coefficient is introduced to improve the calculation method for mass flow rate of the materials.The DEM is employed to simulate the motion of particle groups within the Coriolis force scale under different parameters,and the effects of various structural and operational parameters on the measurement results are compared.The research findings indicate that a lower rotational speed leads to more stable instantaneous measurement results,although the measurement error is relatively large.When the rotational speed exceeds 300 rpm,the measurement error remains within 15%.For materials with a radius of 1–2 mm,the variation range of precision error is approximately 0.4%.Among the structural parameters,the radius of the measurement wheel has the most significant impact on the measurement results,wherein a larger measurement wheel radius corresponds to a smaller measurement error.The horizontal angle of the blades follows as the next influential parameter,with a clockwise rotation and a horizontal angle of 30°resulting in a measurement error below 2%.展开更多
为更加快速准确地从微震时序数据中提取微震事件,提高异常事件的捕捉效率,提出一种基于多尺度融合卷积和空洞卷积的自动编码器(multi-scale fusion convolution and dilated convolutions auto encoder,MDCAE)与融合波动率和限制窗口的...为更加快速准确地从微震时序数据中提取微震事件,提高异常事件的捕捉效率,提出一种基于多尺度融合卷积和空洞卷积的自动编码器(multi-scale fusion convolution and dilated convolutions auto encoder,MDCAE)与融合波动率和限制窗口的动态时间扭曲(constraints dynamic time warping for fusing volatility,CDTW-Vol)方法。提出MDCAE的特征提取方法,将波形信号转变为低维特征信号,引入微震波形的波动率的概念,通过改进后的DTW算法对特征信号进行相似性度量,得到的相似性矩阵进行k-medoids聚类,得到聚类结果。应用某矿区501工作面和802工作面微震监测数据集进行实验,验证所提方法的准确性和泛化性,经实验得出所提聚类方法轮廓系数89%,兰德系数90%,相比普通的k-medoids聚类算法聚类精度上升57%,为捕捉微震系统的异常事件提供了一种新方法。展开更多
The method for simulating the temporal and spatial distribution patterns of leaf area index (LAI) and biomass at landscape scale using remote sensing images and surface data was discussed in this paper. The procedure...The method for simulating the temporal and spatial distribution patterns of leaf area index (LAI) and biomass at landscape scale using remote sensing images and surface data was discussed in this paper. The procedure was: (1) annual maximum normalized difference vegetation index (NDVI) over the landscape was calculated from TM images; (2) the relationship model between NDVI and LAI was built and annual maximum LAI over the landscape was simulated; (3) the relationship models between LAI and biomass were built and annual branch, stem, root and maximum leaf biomass over the landscape were simulated; (4) spatial distribution patterns of leaf biomass and LAI in different periods all the year round were obtained. The simulation was based on spatial analysis module GRID in ArcInfo software. The method is also a kind of scaling method from patch scale to landscape scale. A case study of Changbai Mountain Nature Reserve was dissertated. Analysis and primary validation were carried out to the simulated LAI and biomass for the major vegetation types in the Changbai Mountain in 1995.展开更多
Ground-motion Intensity Measures (IMs) are used to quantify the strength of ground motions and evaluate the response of structures. IMs act as a link between seismic demand and seismic hazard analysis and therefore, h...Ground-motion Intensity Measures (IMs) are used to quantify the strength of ground motions and evaluate the response of structures. IMs act as a link between seismic demand and seismic hazard analysis and therefore, have a key role in performance-based earthquake engineering. Many studies have been carried out on the determination of suitable IMs in terms of effi ciency, suffi ciency and scaling robustness. The majority of these investigations focused on ordinary structures such as buildings and bridges, and only a few were about buried pipelines. In the current study, the optimal IMs for predicting the seismic demand of continuous buried steel pipelines under near-fi eld pulse-like ground motion records is investigated. Incremental dynamic analysis is performed using twenty ground motion records. Using the results of the regression analysis, the optimality of 23 potential IMs are studied. It is concluded that specifi c energy density (SED) followed by VSI[ω1(PGD+RMSd )] are the optimal IMs based on effi ciency, suffi ciency and scaling robustness for seismic response evaluation of buried pipelines under near-fi eld ground motions.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.15572072)the National Key Basic Research and Development Program(Grant Nos.2014CB046803 and 2016ZX05028-002-005)
文摘By focusing on the vulnerability of the structure of marine equipments, together with considering the randomness of meta-ocean load in statistics, a kind of analytical method of fatigue characteristics of marine structure based on full- scale and actual measurement of prototype is proposed. On the basis of short-term field measurement results of structural response, research is carried out on the fatigue analysis of hinge joints at the upper part of the Soft Yoke single point Mooring System (SYMS) by simultaneously monitoring the environmental load and considering the design criteria of offshore structure. Through analysis of finite element modeling, the time-histories of typical stress response are obtained, and then the assessment of fatigue damage at key hinge joints is conducted. The simulation results indicate that the proposed method can accurately analyze the fatigue damage of offshore engineering structure caused by the effect of wave load. The present analytical method of fatigue characteristics can be extended on other offshore engineering structures subjected to meta-ocean load.
基金supported by a grant from the National Social Science Foundation of China (No. 13CTY031)
文摘Background: Self-efficacy has been identified as an important determinant of youth's behavior change including physical activity(PA) participation. However, the dimensionality check of a PA self-efficacy scale has rarely been conducted in China. The current study aims to examine(1) the unidimensionality of a shortened Chinese version of PA self-efficacy scale(S-PASESC);(2) the measurement invariance of S-PASESC across gender and levels of education;(3) the latent factor mean difference between gender and levels of education;(4) the direct effects of self-efficacy on PA by different gender and education levels; and(5) the comparisons of the direct effects of self-efficacy on PA across gender and education levels.Methods: The participants were 5 th through 11 th grade public school students recruited from 7 cities located in different geographic regions of China. The final data include a total of 3003 participants(49.7% boys) who have completed the scales.Results: Confirmatory factor analysis(CFA) test supported the unidimensionality of S-PASESC. The S-PASESC is invariant across gender and 3 levels of education at both configural, full metric, and full scalar levels. Findings from latent mean comparisons showed that boys reported higher PA self-efficacy than girls. Students' perceived PA self-efficacy tend to decrease from elementary to high school. Finally, self-efficacy positively related to PA by groups of different gender and education levels and the relationship between self-efficacy and PA is stronger among middle school boys than girls.Conclusion: Findings suggest S-PASESC is a valid scale for measuring Chinese students' PA self-efficacy.
文摘Utilization of wind energy is a promising way to generate power,and wind turbine blades play a key role in collecting the wind energy effectively.This paper attempts to measure the deformation parameter of wind turbine blades in mechanics experiments using a videometric method. In view that the blades experience small buckling deformation and large integral deformation simultaneously, we proposed a parallel network measurement(PNM) method including the key techniques such as camera network construction,camera calibration,distortion correction,the semi-automatic high-precision extraction of targets,coordinate systems unification,and bundle adjustment,etc. The relatively convenient construction method of the measuring system can provide an abundant measuring content,a wide measuring range and post processing.The experimental results show that the accuracy of the integral deformation measurement is higher than 0.5 mm and that of the buckling deformation measurement higher than 0.1mm.
基金supported by the National Natural Science Foundation of China(Grant Nos.61871386,61971427,62035014,and 61921001)the Natural Science Fund for Distinguished Young Scholars of Hunan Province,China(Grant No.2019JJ20022)。
文摘In the terahertz band,the dispersive characteristic of dielectric material is one of the major problems in the scaled radar cross section(RCS)measurement,which is inconsistent with the electrodynamics similitude deducted according to the Maxwell’s equations.Based on the high-frequency estimation method of physical optics(PO),a scaled RCS measurement method for lossy objects is proposed through dynamically matching the reflection coefficients according to the distribution of the object facets.Simulations of the model of SLICY are conducted,and the inversed RCS of the lossy prototype is obtained using the proposed method.Comparing the inversed RCS with the calculated results,the validity of the proposed method is demonstrated.The proposed method provides an effective solution to the scaled RCS measurement for lossy objects in the THz band.
文摘Background: Bonding disorders affect the growth and development of infants. In Japan, the Japanese version of the Mother-to-Infant Bonding Scale (MIBS-J) is widely used for early detection of bonding disorders. Repeated use of a questionnaire has problems of reduced validity. In order to correctly detect bonding disorders at multiple time points, it is necessary to confirm the measurement invariance of the scale. Baba et al. reported that invariance of the MIBS-J factor structure could only be obtained by abridging the scale into three items. Purpose: The aim of this study was to 1) confirm the factor structure and measurement invariance of the MIBS-J between two measurement times and 2) to examine factors that can be used without being affected by measurement time in order to identify item that contribute to measure met invariance. Methods: We analysed the data of 1049 and 878 mothers with a neonate collected in two waves: 5 days (Wave 1) and 1 month postpartum (Wave 2). Exploratory and confirmatory factor analyses were conducted on the data randomly divided into two groups in each wave. Results: The three-item model (MIBS-J items 1, 6, and 8) was most accepted. Measurement invariance and structural invariance were confirmed in the model. This was consistent with Baba et al.’s model. Conclusion: The three MIBS-J items showed measurement invariance and structural invariance in Japanese mothers during 1 month postpartum.
文摘In this paper, we presented a method of using the l as er scanning triangulation for the non-contact 3D surface profile measurement of large-scale object. The characteristic of large-scale object non-contact mea surement is analyzed and the measuring method is proposed. Main factors influenc ing measurement precision such as image distortion and accurate designation of s peckle center are analyzed and methods of solving these problems are proposed. W e designed a combined filter by which the pulse noise and the Gaussian noise of speckle image can be eliminated efficiently. Using the characteristic of intensi ty distribution of laser speckle image we proposed a new approximating method th at could locate the center of laser speckle image at sub-pixel. The auxiliary v ariables are set to linearize the relationship between the image displacement an d the distance, the accurate values of laser triangulation system parameters cou ld be calibrated accurately and the measuring precision is increased remarkabl y. Using the above techniques we designed a measuring system based on laser sc anning triangulation. The results of the experiment show that these methods can raise the measuring precision of large-scale 3D surface profile effectively.
基金supported by Key Program of National Natural Science Foundation of China (Grant No. 50735003)
文摘Spatial angle measurement, especially the measurement of horizontal and vertical angle, is a basic method used for industrial large-scale coordinate measurement. As main equipments in use, both theodolites and laser trackers can provide very high accuracy for spatial angle measurement. However, their industrial applications are limited by low level of automation and poor parallelism. For the purpose of improving measurement efficiency, a lot of studies have been conducted and several alternative methods have been proposed. Unfortunately, all these means are either low precision or too expensive. In this paper, a novel method of spatial angle measurement based on two rotating planar laser beams is proposed and demonstrated. Photoelectric receivers placed on measured points are used to receive the rotating planner laser signals transmitted by laser transmitters. The scanning time intervals of laser planes were measured, and then measured point's horizontal/vertical angles can be calculated. Laser plane's angle parameters are utilized to establish the abstract geometric model of transmitter. Calculating formulas of receiver's horizontal/vertical angles have been derived. Measurement equations' solvability conditions and judgment method of imaginary solutions are also presented after analyzing. Proposed method for spatial angle measurement is experimentally verified through a platform consisting of one laser transmitter and one optical receiver. The transmitters used in new method are only responsible for providing rotating light plane signals carrying angle information. Receivers automatically measure scanning time of laser planes and upload data to the workstation to calculate horizontal angle and vertical angle. Simultaneous measurement of multiple receivers can be realized since there is no human intervention in measurement process .Spatial angle measurement result indicates that the repeatable accuracy of new method is better than 10". Proposed method can improve measurement's automation degree and speed while ensuring measurement accuracy.
基金Project (60674020) supported by the National Natural Science Foundation of ChinaProject (Z2006G11) supported by Specialized Natural Science Fund of Shandong Province,China
文摘The global exponentially stability was studied for time-delay and time-varying measure large scale systems with impulsive effects. Firstly, the concepts are drawn for the functional category. Secondly, some sufficient conditions of the uniformly stability and the global exponentially stability are given for the above systems through defining a Lyapunov function of the weighting sum of the variable absolute by using the Lyapunov function method and the comparison principle. At the same time, the new conclusion of stability of these systems is more universal and contains the existing results. Finally, an example is given to illustrate the feasibility and validity of the obtained results.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51208389)the Fundamental Research Funds for the Central Universities+1 种基金the State Key Lab of Subtropical Building Science,South China University of Technology(Grant No.2010ZA01)the "Eleven-Five" Science and Technology Supporting Project in China
文摘Remote sensing and on-site measurement are used to determine the heat environment within a community,and are compared the differences for heat analysis. The two methods perform differently for various underlying surfaces. The individual methods can detect different aspects of the heat environment,which used in combination are useful for heat island research. The differences in estimated air and surface temperatures are smaller in open space and more obvious for vegetated surfaces. Ventilation does not affect the difference between air and surface temperature in open areas,and the vegetation surface and shading moderates surface temperature more effectively than the water surface; The forest is a type of underlying surface with heat comfortable,in which the feeling of air temperature is much difference to the structure of heat environment that should be survey and detected separately. The two methods can be used to study different aspects of the heat environment,thus forming a comprehensive approach for planners in urban and rural spaces.
文摘The study examined the measurement invariance (configural,metric,scalar,and error variances) and factor mean scores equivalencies of a modified version of the Strengths and Weaknesses of ADHDSymptoms and Normal Behavior Scale (SWAN-M) across ratings provided by mothers of clinic-referred children and adolescents,diagnosed with (N = 666) and without (N = 202) ADHD. Confirmatory factor analysis (CFA) of these ratings provided support for the bi-factor model of ADHD [orthogonal general and specific factors for inattention (IA) and hyperactivity/impulsivity (HI) symptoms]. Multiple-group confirmatory factor analysis (CFA) of the bi-factor model supported full measurement invariance. Findings also showed that for latent mean scores,the ADHD group had higher scores than the non-ADHD group for the ADHD general and IA specific factors. The findings indicate that observed scores (based on maternal ratings of the SWAN-M) are comparable,as they have the same measurement properties. The theoretical,psychometric and clinical implications of the findings are discussed.
文摘Objective To explore the possibility of diagnosis types of acute stroke, elevating treatment quality and promoting prognosis with acute stroke clinical measuring scale . Methods To gain a measuring scale formula and simplify this formula after stepwise regression Fisher distinguish analysis to 18 clinical variable of 184 acute stroke patients and to validate its sensitivity, specificity and positive foretell value to diagnosis of acute stroke. Results We gained scale that Y=0.617×action+0.485×BP+1.241×headache+0.74×vomiting+0.955×cervical resistance-1.215×TIA-0.727×heart disease-2.78;sensitivity of this formula to diagnosis of cerebral infarction and cerebral hemorrhage was 90.5%and 70%respectively,its specificity was 70%and 90.5%respectively,positive foretell value was 71.7%and 89.7%(Y≥0 means cerebral hemorrhage,Y<0 means cerebral infarction). Simple formula is S=0.5×action+0.5×BP+1×headache+1×vomiting+1×cervical resistance-1×TIA-1×hear disease-3;its sensitivity was 89.3%and 68%,specificity was 68%and 89.3%,positive foretell value was 70.1%and 88.3%.There was no apparent difference in sensitivity; specificity and positive foretell value between two formulas. Conclusion Acute stroke clinical measuring scale can help early diagnosis, treatment and rehabilitation of cerebral stroke patients.
基金Natural Science Foundation of jilin Province(grant No.20230101329JC).
文摘The Coriolis force method is a recently developed and highly regarded direct measurement technique that enables high-precision measurement of bulk materials.The operational parameters and variations thereof directly influence the measurement accuracy of the equipment.In this study,a measurement correction coefficient is introduced to improve the calculation method for mass flow rate of the materials.The DEM is employed to simulate the motion of particle groups within the Coriolis force scale under different parameters,and the effects of various structural and operational parameters on the measurement results are compared.The research findings indicate that a lower rotational speed leads to more stable instantaneous measurement results,although the measurement error is relatively large.When the rotational speed exceeds 300 rpm,the measurement error remains within 15%.For materials with a radius of 1–2 mm,the variation range of precision error is approximately 0.4%.Among the structural parameters,the radius of the measurement wheel has the most significant impact on the measurement results,wherein a larger measurement wheel radius corresponds to a smaller measurement error.The horizontal angle of the blades follows as the next influential parameter,with a clockwise rotation and a horizontal angle of 30°resulting in a measurement error below 2%.
文摘为更加快速准确地从微震时序数据中提取微震事件,提高异常事件的捕捉效率,提出一种基于多尺度融合卷积和空洞卷积的自动编码器(multi-scale fusion convolution and dilated convolutions auto encoder,MDCAE)与融合波动率和限制窗口的动态时间扭曲(constraints dynamic time warping for fusing volatility,CDTW-Vol)方法。提出MDCAE的特征提取方法,将波形信号转变为低维特征信号,引入微震波形的波动率的概念,通过改进后的DTW算法对特征信号进行相似性度量,得到的相似性矩阵进行k-medoids聚类,得到聚类结果。应用某矿区501工作面和802工作面微震监测数据集进行实验,验证所提方法的准确性和泛化性,经实验得出所提聚类方法轮廓系数89%,兰德系数90%,相比普通的k-medoids聚类算法聚类精度上升57%,为捕捉微震系统的异常事件提供了一种新方法。
基金One Hundred Talents Program of CAS No.CXIOG-C00-01+1 种基金 National Natural Science Foundation of China No.39970613
文摘The method for simulating the temporal and spatial distribution patterns of leaf area index (LAI) and biomass at landscape scale using remote sensing images and surface data was discussed in this paper. The procedure was: (1) annual maximum normalized difference vegetation index (NDVI) over the landscape was calculated from TM images; (2) the relationship model between NDVI and LAI was built and annual maximum LAI over the landscape was simulated; (3) the relationship models between LAI and biomass were built and annual branch, stem, root and maximum leaf biomass over the landscape were simulated; (4) spatial distribution patterns of leaf biomass and LAI in different periods all the year round were obtained. The simulation was based on spatial analysis module GRID in ArcInfo software. The method is also a kind of scaling method from patch scale to landscape scale. A case study of Changbai Mountain Nature Reserve was dissertated. Analysis and primary validation were carried out to the simulated LAI and biomass for the major vegetation types in the Changbai Mountain in 1995.
文摘Ground-motion Intensity Measures (IMs) are used to quantify the strength of ground motions and evaluate the response of structures. IMs act as a link between seismic demand and seismic hazard analysis and therefore, have a key role in performance-based earthquake engineering. Many studies have been carried out on the determination of suitable IMs in terms of effi ciency, suffi ciency and scaling robustness. The majority of these investigations focused on ordinary structures such as buildings and bridges, and only a few were about buried pipelines. In the current study, the optimal IMs for predicting the seismic demand of continuous buried steel pipelines under near-fi eld pulse-like ground motion records is investigated. Incremental dynamic analysis is performed using twenty ground motion records. Using the results of the regression analysis, the optimality of 23 potential IMs are studied. It is concluded that specifi c energy density (SED) followed by VSI[ω1(PGD+RMSd )] are the optimal IMs based on effi ciency, suffi ciency and scaling robustness for seismic response evaluation of buried pipelines under near-fi eld ground motions.