期刊文献+
共找到6,918篇文章
< 1 2 250 >
每页显示 20 50 100
Measurement Research Based on Bayesian Structural Equation Cognitive Model
1
作者 Shuixian Fei Sanzhi Shi +4 位作者 Jixin Li Jiali Zheng Xinyi Yu Yifan Huang Xiang Li 《Journal of Applied Mathematics and Physics》 2024年第4期1163-1177,共15页
The Bayesian structural equation model integrates the principles of Bayesian statistics, providing a more flexible and comprehensive modeling framework. In exploring complex relationships between variables, handling u... The Bayesian structural equation model integrates the principles of Bayesian statistics, providing a more flexible and comprehensive modeling framework. In exploring complex relationships between variables, handling uncertainty, and dealing with missing data, the Bayesian structural equation model demonstrates unique advantages. Therefore, Bayesian methods are used in this paper to establish a structural equation model of innovative talent cognition, with the measurement of college students’ cognition of innovative talent being studied. An in-depth analysis is conducted on the effects of innovative self-efficacy, social resources, innovative personality traits, and school education, aiming to explore the factors influencing college students’ innovative talent. The results indicate that innovative self-efficacy plays a key role in perception, social resources are significantly positively correlated with the perception of innovative talents, innovative personality tendencies and school education are positively correlated with the perception of innovative talents, but the impact is not significant. 展开更多
关键词 Bayesian structural Equation Model Innovative Talents measure of Cognition Innovative Self-Efficacy Social Resources
下载PDF
Non-Kramers doublet ground state in a quaternary cubic compound PrRu_(2)In_(2)Zn_(18) investigated by ultrasonic measurements
2
作者 张化远 Kazuhei Wakiya +2 位作者 Mitsuteru Nakamura Masahito Yoshizawa Yoshiki Nakanish 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期405-411,共7页
We performed ultrasonic measurements on a quaternary cubic compound PrRu_(2)In_(2)Zn_(18) to explore the ground state properties derived from non-Kramers Γ_(3) doublet of Pr^(3+).PrRu_(2)In_(2)Zn_(18) is a quaternary... We performed ultrasonic measurements on a quaternary cubic compound PrRu_(2)In_(2)Zn_(18) to explore the ground state properties derived from non-Kramers Γ_(3) doublet of Pr^(3+).PrRu_(2)In_(2)Zn_(18) is a quaternary derivative of the ternary compound PrRu_(2)Zn_(20) that exhibits a structural phase transition at T_S=138 K.In PrRu_(2)In_(2)Zn_(18),the Zn atoms at the 16c site in PrRu_(2)Zn_(20) are selectively replaced by In atoms.A monotonic increase was observed in the temperature dependence of elastic constants C_L=(C_(11)+2C_(12)+4C_(44))/3 and C_(T)=(C_(11)-C_(12)+C_(44))/3 in the temperature range around T_(S) to which an elastic softening was observed in(C_(11)-C_(12))/2 for PrRu_(2)Zn_(20).The disappearance of the softening indicates that the structural transition in PrRu_(2)Zn_(20) is suppressed by the substitution of Zn ions by In ones with a larger ionic radius.Alternatively,the C_(T) of PrRu_(2)In_(2)Zn_(18) exhibits a precursor Curie-type elastic softening toward low temperatures being responsible for the non-Kramers Γ_(3) ground state.We discuss the ground state and the evolution of the elastic properties of the different single-crystal samples of PrRu_(2)In_(2)Zn_(18) grown under different conditions. 展开更多
关键词 ultrasonic measurements non-Kramers doublet structural phase transition crystalline electric field effect
下载PDF
Local measurement for structural health monitoring 被引量:1
3
作者 祁贵仲 郭迅 +2 位作者 齐霄斋 董伟民 P.Chang 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2005年第1期165-172,共8页
Localized nature of damage in structures requires local measurements for structural health monitoring. The local measurement means to measure the local, usually higher modes of the vibration in a structure. Three fund... Localized nature of damage in structures requires local measurements for structural health monitoring. The local measurement means to measure the local, usually higher modes of the vibration in a structure. Three fundamental issues about the local measurement for structural health monitoring including (1) the necessity of making local measurement, (2) the difficulty of making local measurement and (3) how to make local measurement are addressed in this paper. The results from both the analysis and the tests show that the local measurement can successfully monitor the structural health status as long as the local modes are excited. Unfortunately, the results also illustrate that it is difficult to excite local modes in a structure. Therefore, in order to carry structural health monitoring into effect, we must (1) ensure that the local modes are excited, and (2) deploy enough sensors in a structure so that the local modes can be monitored. 展开更多
关键词 structure health monitoring local measurement local modes higher modes local modes EXCITATION SENSORS structural vibration
下载PDF
Problems of durability and reinforcement measures for underground structures in China 被引量:1
4
作者 Xianming Zeng Zhenyu Wang +3 位作者 Junqi Fan Lin Zhao Dalu Lin Jian Zhao 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2011年第3期250-259,共10页
In this paper, the bolt- and cable-supported structures mainly refer to anchored cables, anchored bolts, soil nails and other commonly used reinforcing and supporting structures in geotechnical engineering, as well as... In this paper, the bolt- and cable-supported structures mainly refer to anchored cables, anchored bolts, soil nails and other commonly used reinforcing and supporting structures in geotechnical engineering, as well as reinforced soil structures in permanent works. They are often used in combination, or formed into composite bolt-and cable-supported structures, with other traditional construction methods and relevant measures. Distinct characteristics of such structures are that they are most often invisible, exposed to more severe underground corrosive environments and with strict durability requirements. A number of serious durability problems of underground structures are discussed and major achievements and advances in China and abroad in terms of durability and reinforcement measures for underground structures are reviewed, followed by comprehensive analyses. Some suggestions for those problems are put forward. 展开更多
关键词 underground structures DURABILITY service life reinforcement measures
下载PDF
STRUCTURAL PARAMETERS CALIBRATION BY POSTURE MEASUREMENT ON PARALLEL 6-DOF PLATFORM 被引量:1
5
作者 Wu Jiangning Li ShilunState Key Laboratory of Fluid Power Transmission and Control, Zhejiang University,Hangzhou 310027, China 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2002年第4期334-338,343,共6页
Some approaches to measure parallel 6-degree of freedom platform's posturestatically and to calibrate the platform's actual structural parameters by measuring a series of theplatform's varying postures are... Some approaches to measure parallel 6-degree of freedom platform's posturestatically and to calibrate the platform's actual structural parameters by measuring a series of theplatform's varying postures are studied. In the case where high posture accuracy is requiredrelatively, to obtain the platform's actual structural parameters is very important. Threedimensions measurement with 2 theodolites are used to obtain the platform's postures statically andNewton iterative method is adopted to calibrate structural parameters. Some measures taken in themeasurement and the calibration are discussed in detail. And the experiment results of theplatform's posture control before and after the calibration are given. The results show that theplatform's posture control accuracy after the calibration is improved notably. 展开更多
关键词 parallel 6-DOF platform theodolite posture measurement nonlinearequation group structural parameters calibration
下载PDF
Eco-environmental Impact Assessment of the Change of Regional Industrial Structure and Regulative Measures 被引量:2
6
作者 Zhang Jian 《Chinese Journal of Population,Resources and Environment》 北大核心 2008年第2期8-17,共10页
Acting as an important driving force for the change of the regional land use,the change of industrial structure also has some influences on the ecological environment.The assessment and mechanism analysis of these inf... Acting as an important driving force for the change of the regional land use,the change of industrial structure also has some influences on the ecological environment.The assessment and mechanism analysis of these influences will be beneficial to the sustainable development of regional economy and the im- provement of relationships between man and earth.Taking Chuzhou City in Anhui Province as an example,on the basis of a qualitative analysis of the influence of the development of differ- ent industry on the regional ecological environment,this paper builds the influence factor of industrial structure on natural envi- ronment and the influence index of industrial structure on natural environment,makes a quantitative assessment of the change of the industrial structure and its comprehensive influences on the eco- logical environment in the Chuzhou City from 1974 to 1995. Studies show that,during the analysed period,Chuzhou City's industrial structure has changed markedly,having undergone two transformations.The influence of industrial structure on natural environment from 1974 to 1995 increased as a whole,while from 1996 to 2004,the influence of industrial structure on natural en- vironment decreased year-on-year.These changes indicate that the regional change of industrial structure results in better ecological effects.Finally,we propose appropriate regulatory measures ac- cording to our research results. 展开更多
关键词 change of industrial structure eco-environmental effect Chuzhou City measures
下载PDF
Structural Health Monitoring by Accelerometric Data of a Continuously Monitored Structure with Induced Damages
7
作者 Giada Faraco Andrea Vincenzo De Nunzio +1 位作者 Nicola Ivan Giannoccaro Arcangelo Messina 《Structural Durability & Health Monitoring》 EI 2024年第6期739-762,共24页
The possibility of determining the integrity of a real structure subjected to non-invasive and non-destructive monitoring,such as that carried out by a series of accelerometers placed on the structure,is certainly a g... The possibility of determining the integrity of a real structure subjected to non-invasive and non-destructive monitoring,such as that carried out by a series of accelerometers placed on the structure,is certainly a goal of extreme and current interest.In the present work,the results obtained from the processing of experimental data of a real structure are shown.The analyzed structure is a lattice structure approximately 9 m high,monitored with 18 uniaxial accelerometers positioned in pairs on 9 different levels.The data used refer to continuous monitoring that lasted for a total of 1 year,during which minor damage was caused to the structure by alternatively removing some bracings and repositioning them in the structure.Two methodologies detecting damage based on decomposition techniques of the acquired data were used and tested,as well as a methodology combining the two techniques.The results obtained are extremely interesting,as all the minor damage caused to the structure was identified by the processing methods used,based solely on the monitored data and without any knowledge of the real structure being analyzed.The results use 15 acquisitions in environmental conditions lasting 10 min each,a reasonable amount of time to get immediate feedback on possible damage to the structure. 展开更多
关键词 structural health monitoring damage detection vibration measurements stochastic subspace identification
下载PDF
Multi-View Structured Light 3D Measurement System
8
作者 LU Ping ZHANG Yingjie +2 位作者 DENG Fangwei LIU Wei HUANG Shijun 《ZTE Communications》 2024年第4期53-58,共6页
Vision-based measurement technology benefits high-quality manufacturers through improved dimensional precision,enhanced geo-metric tolerance,and increased product yield.The monocular 3D structured light visual sensing... Vision-based measurement technology benefits high-quality manufacturers through improved dimensional precision,enhanced geo-metric tolerance,and increased product yield.The monocular 3D structured light visual sensing method is popular for detecting online parts since it can reach micron-meter depth accuracy.However,the line-of-sight requirement of a single viewpoint vision system often fails when hiding occurs due to the object’s surface structure,such as edges,slopes,and holes.To address this issue,a multi-view 3D structured light vi-sion system is proposed in this paper to achieve high accuracy,i.e.,Z-direction repeatability,and reduce hiding probability during mechani-cal dimension measurement.The main contribution of this paper includes the use of industrial cameras with high resolution and high frame rates to achieve high-precision 3D reconstruction.Moreover,a multi-wavelength(heterodyne)phase expansion method is employed for high-precision phase calculation.By leveraging multiple industrial cameras,the system overcomes field of view occlusions,thereby broadening the 3D reconstruction field of view.Finally,the system achieves a Z-axis repetition accuracy of 0.48µm. 展开更多
关键词 3D measurement structured light MULTI-VIEW
下载PDF
Spatial effect of environmental regulation measures on industrial structure upgrading from the empirical analysis of Beijing-Tianjin-Hebei region and its surrounding areas 被引量:1
9
作者 Guoxing Zhang Peide Zhang +2 位作者 Nana Deng Haixu Bao Jiexun Li 《Chinese Journal of Population,Resources and Environment》 2019年第3期267-277,共11页
This paper investigates the spatial effect of environmental regulation measures on the upgrading of industrial structure in the integrated development strategy of Beijing-Tianjin-Hebei region and its surrounding areas... This paper investigates the spatial effect of environmental regulation measures on the upgrading of industrial structure in the integrated development strategy of Beijing-Tianjin-Hebei region and its surrounding areas.In order to reflect the effect of the environmental regulation and different regulation measures more truly,this paper constructs indices of the environmental regulation measures through the results of policy texts quantification.On the basis of the previous research,this paper divides environmental regulation into the following types:personnel and administrative measures of command and control;market-oriented fiscal,taxation,financial and other economic measures;guidance measures.Spatial panel regression results show that administrative measures of command control and market-oriented fiscal measures have a significant role in promoting regional industrial structure upgrading,but not conducive to the advancement of the industrial structure of adjacent areas.Their roles in promoting and inhibition are counteracted,which causes the total effect of industrial structure upgrading of Beijing-Tianjin-Hebei and the surrounding areas are not significant.Personnel measures,financial measures,other economic measures and guidance measures do not have the short-term effect and spatial effect on the upgrading of industrial structure. 展开更多
关键词 Beijing-Tianjin-Hebei and its surrounding areas policy quantification environmental regulatory measures upgrading of industrial structure
下载PDF
ESTIMATING STRUCTURAL INERTIA PROPERTIES FROM VIBRATION MEASUREMENTS
10
作者 Zeng Qinghua(Institute of Vibration Engineering,Nanjing University of Aeronauticsand Aslronautics)Nanjing,China,210016 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1995年第2期118-124,共7页
ESTIMATINGSTRUCTURALINERTIAPROPERTIESFROMVIBRATIONMEASUREMENTSESTIMATINGSTRUCTURALINERTIAPROPERTIESFROMVIBRA... ESTIMATINGSTRUCTURALINERTIAPROPERTIESFROMVIBRATIONMEASUREMENTSESTIMATINGSTRUCTURALINERTIAPROPERTIESFROMVIBRATIONMEASUREMENTS¥... 展开更多
关键词 structurES INERTIA PROPERTIES vibration measurement
下载PDF
Estimation of Aleatory Randomness by S_(a)(T_(1))-Based Intensity Measures in Fragility Analysis of Reinforced Concrete Frame Structures
11
作者 Yantai Zhang Yongan Shi +1 位作者 Baoyin Sun ZhengWang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第1期73-96,共24页
Based on the multiple stripes analysis method,an investigation of the estimation of aleatory randomness by S_(a)(T_(1))-based intensity measures(IMs)in the fragility analysis is carried out for two typical low-and med... Based on the multiple stripes analysis method,an investigation of the estimation of aleatory randomness by S_(a)(T_(1))-based intensity measures(IMs)in the fragility analysis is carried out for two typical low-and mediumrise reinforced concrete(RC)frame structures with 4 and 8 stories,respectively.The sensitivity of the aleatory randomness estimated in fragility curves to various S_(a)(T_(1))-based IMs is analyzed at three damage limit states,i.e.,immediate occupancy,life safety,and collapse prevention.In addition,the effect of characterization methods of bidirectional ground motion intensity on the record-to-record variability is investigated.It is found that the damage limit state of the structure has an important influence on the applicability of the ground motion IM.The S_(a)(T_(1))-based IMs,considering the effect of softened period,can maintain lower record-to-record variability in the three limit states,and the S_(a)(T_(1))-based IMs,considering the effect of higher modes,do not show their advantage over S_(a)(T_(1)).Furthermore,the optimal multiplier C and exponentαin the dual-parameter ground motion IM are proposed to obtain a lower record-to-record variability in the fragility analysis of different damage limit state.Finally,the improved dual-parameter ground motion IM is applied in the risk assessment of the 8-story frame structure. 展开更多
关键词 RC frame structure intensity measure fragility analysis record-to-record variability softened period risk assessment
下载PDF
A New Technology to Measure the Thermoelectric Performance of Nanowire Array Structure 被引量:1
12
作者 王为 王惠 高建平 《Transactions of Tianjin University》 EI CAS 2002年第4期243-245,共3页
Recently, the study on one-dimensional thermoelectric materials is getting more and more attention. For those one-dimensional thermoelectric materials with nanowire array structure fabricated with alumina film as temp... Recently, the study on one-dimensional thermoelectric materials is getting more and more attention. For those one-dimensional thermoelectric materials with nanowire array structure fabricated with alumina film as template, its thickness is often in the range of 10 to several tens micrometers, and the conventional measurement cannot be used. The key difficulties of the thermoelectric performance measurement for nanowire array materials include two aspects: 1) How to heat the two sides of the specimen uniformly and keep the temperature difference constantly at the same time; 2) How to measure the temperature of the two sides of the specimen with the thickness of 10 to several tens micrometers. A new type heating and temperature measuring technology has been used, and it can be simply described as liquid heating and separate temperature measurement. According to this principle, a thermoelectric performance measurement system has been established. 展开更多
关键词 measuring technology thermoelectric performance nanowire array structure thermoelectric materials
全文增补中
Vector-intensity measure based seismic vulnerability analysis of bridge structures 被引量:8
13
作者 Li Zhongxian Li Yang Li Ning 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第4期695-705,共11页
This paper presents a method for seismic vulnerability analysis of bridge structures based on vector-valued intensity measure (viM), which predicts the limit-state capacities efficiently with multi-intensity measure... This paper presents a method for seismic vulnerability analysis of bridge structures based on vector-valued intensity measure (viM), which predicts the limit-state capacities efficiently with multi-intensity measures of seismic event. Accounting for the uncertainties of the bridge model, ten single-bent overpass bridge structures are taken as samples statistically using Latin hypercube sampling approach. 200 earthquake records are chosen randomly for the uncertainties of ground motions according to the site condition of the bridges. The uncertainties of structural capacity and seismic demand are evaluated with the ratios of demand to capacity in different damage state. By comparing the relative importance of different intensity measures, Sa(T1) and Sa(T2) are chosen as viM. Then, the vector-valued fragility functions of different bridge components are developed. Finally, the system-level vulnerability of the bridge based on viM is studied with Duunett- Sobel class correlation matrix which can consider the correlation effects of different bridge components. The study indicates that an increment IMs from a scalar IM to viM results in a significant reduction in the dispersion of fragility functions and in the uncertainties in evaluating earthquake risk. The feasibility and validity of the proposed vulnerability analysis method is validated and the bridge is more vulnerable than any components. 展开更多
关键词 bridge structure seismic vulnerability analysis vector-valued intensity measure components' correlation system vulnerability
下载PDF
Structural Design and Protective Methods for the 100 kW Shoreline Wave Power Station 被引量:7
14
作者 游亚戈 郑永红 +2 位作者 马玉久 余志 蒋念东 《海洋工程:英文版》 2003年第3期439-448,共10页
The structural design and protective methods for the 100 kW shoreline wave power station in China are described in detail. The proper structural type is designed for effective minimization of wave loads and bending st... The structural design and protective methods for the 100 kW shoreline wave power station in China are described in detail. The proper structural type is designed for effective minimization of wave loads and bending stress. Various protective devices are adopted to protect the station in the extreme conditions against excessive power of airflow, excessive torsion of the shaft, over-pressure of the chamber, over-speed of rotation, power failure, and so on. It turns out that the structural design and protective methods for the 100 kW shoreline wave power station are successful. 展开更多
关键词 wave power station structural design protective measures
下载PDF
Field Measurements of Influence of Sand Transport Rate on Structure of Wind-sand Flow over Coastal Transverse Ridge 被引量:10
15
作者 DONG Yuxiang S L NAMIKAS +1 位作者 P A HESP MA Jun 《Chinese Geographical Science》 SCIE CSCD 2008年第3期255-261,共7页
The structure of wind-sand flow under different total sand transport rates was measured with field vertical anemometer and sand trap on the crest of typical coastal transverse ridge in Changli Gold Coast of Hebei Prov... The structure of wind-sand flow under different total sand transport rates was measured with field vertical anemometer and sand trap on the crest of typical coastal transverse ridge in Changli Gold Coast of Hebei Province, which is one of the most typical coastal aeolian distribution regions in China and famous for the tall and typical coastal transverse ridges. The measurement results show that, on the conditions of approximate wind velocities and same surface materials and environments, some changes happen to the structure of wind-sand flow with the increase of total sand transport rate on the crest of coastal transverse ridge. First, the sand transport rates of layers at different heights in the wind-sand flow increase, with the maximum increase at the height layer of 4-8cm. Second, the ratios of sand trans-port rates of layers at different heights to total sand transport rate decrease at the low height layer (0-4cm), but increase at the high height layer (4-60cm). Third, the distribution of the sand transport rate in the wind-sand flow can be expressed by an exponential function at the height layer of 0-40cm, but it changes from power function model to ex-ponential function model in the whole height layer (0-60cm) and changes into polynomial function model at the height layer of 40-60cm with the increase of total sand transport rate. Those changes have a close relationship with the limit of sand grain size of wind flow transporting and composition of sand grain size in the wind-sand flow. 展开更多
关键词 sand transport rate coastal transverse ridge structure of wind-sand flow field measurement
下载PDF
A comparison of summer precipitation structures over the South China Sea and the East China Sea based on tropical rainfall measurement mission 被引量:3
16
作者 LI Jiangnan YANG Chaofeng +2 位作者 LI Fangzhou HE Qihua LI Weibiao 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第11期41-49,共9页
The three-dimensional structures of summer precipitation over the South China Sea (SCS) and the East China Sea (ECS) are investigated based on tropical rainfall measurement mission (TRMM). The primary results ar... The three-dimensional structures of summer precipitation over the South China Sea (SCS) and the East China Sea (ECS) are investigated based on tropical rainfall measurement mission (TRMM). The primary results are as follows. First, both the convective and stratiform precipitation rates in the SCS are much higher than those of the ECS. The contribution of the convective cloud precipitation to the surface precipitation is primarily over the SCS and the ECS with a proportion of about 70%, but the contribution of convective cloud precipitation is slightly larger in the SCS than the ECS. The contribution of stratus precipitation is slightly larger in the ECS than that in the SCS. Second, the content of cloud particles and precipitation particles in the ECS in June was greater than that in the SCS, while in July and August, the content of cloud and precipitation particles in the ECS was less than that in the SCS. Third, the latent heat profile of the ECS is quite different from that of the SCS. In June, the peak values of evaporation and condensation latent heating rates in the ECS are greater than those in the SCS. In July and August, however, the peak values of evaporation and condensation latent heating rates in the ECS are about 0.05°/h less than those in the SCS. 展开更多
关键词 PRECIPITATION three-dimensional structures tropical rainfall measurement mission SouthChina Sea East China Sea
下载PDF
Analysis on Structural Control of Coal Distribution in the Northern Qaidam Basin,NW China 被引量:3
17
作者 LIU Tianji WANG Tong ZHAN Wenfeng 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2008年第3期690-696,共7页
The distribution of the Jurassic coal measures in the northern Qaidam Basin is obviously controlled by the regional structures. Based on the existing data of coalfield exploration and combined with the analysis of coa... The distribution of the Jurassic coal measures in the northern Qaidam Basin is obviously controlled by the regional structures. Based on the existing data of coalfield exploration and combined with the analysis of coalfield basement structures, features of the main faults, and the distribution of coal measures, this paper brings forward a scheme of coalfield tectonic divisional units and the definition of the coal-controlling structural styles in the northern Qaidam Basin. The structure control of the distribution of coal measures is further discussed. Several stages of regional tectonic activities since the Indosinian has led to the distribution of coal measures into the characteristics of zonation from the north to south and block from east to west. The results indicate that the structural deformations are the most intense in the front of the three uplifted belts, which are characterized by the combination of thrusts. The coal measures are uplifted to the shallow formations, and are easy to be exploited, but the scale of mines is small because of serious damages by the coal distribution. On the contrary, the stress and strain are weak in the three depressions, with the coal-controlling structural styles being mainly the thrust-fold and thrust-monocline combinations. The distribution of coals in the depressions is relatively stable. The shallower part of the depression will become the key areas for exploration and development of coal resources in the northern Qaidam Basin. 展开更多
关键词 northern Qaidam Basin tectonic units coal-controlling structural styles distribution regularity of coal measures
下载PDF
MEASURING STRUCTURE COMPLEXITY OF UML CLASS DIAGRAMS 被引量:6
18
作者 Zhou Yuming Xu Baowen (Dept. of Computer Science & Eng., Southeast Univ., Nanjing 210096) (State Key Laboratory of Software Engineering, Wuhan University, Wuhan 430072) (Jiangsu Key Lab. of Computer Info. Proc. Tech., Soochow Univ., Suzhou 215006) 《Journal of Electronics(China)》 2003年第3期227-231,共5页
To provide system designer a valid measure to evaluate the structure complexityof class diagrams objectively, this letter first proposes a method to transform a class diagramsinto a weighted class dependence graph, th... To provide system designer a valid measure to evaluate the structure complexityof class diagrams objectively, this letter first proposes a method to transform a class diagramsinto a weighted class dependence graph, then presents a structure complexity measure for classdiagrams based on entropy distance. 展开更多
关键词 Class diagrams structure complexity measurE Entropy distance DEPENDENCE
下载PDF
Comparison of satellite images with different spatial resolutions to estimate stand structural diversity in urban forests 被引量:1
19
作者 Ulas Yunus Ozkan Ibrahim Ozdemir +2 位作者 Tufan Demirel Serhun Saglam Ahmet Yesil 《Journal of Forestry Research》 SCIE CAS CSCD 2017年第4期805-814,共10页
The structural diversity in urban forests is highly important to protect biodiversity. In particular, fruit trees and bush species, cavity-bearing trees and coarse, woody debris provide habitats for animals to feed, n... The structural diversity in urban forests is highly important to protect biodiversity. In particular, fruit trees and bush species, cavity-bearing trees and coarse, woody debris provide habitats for animals to feed, nest and hide. Improper silvicultural practices, intensive recreational use and illegal harvesting lead to a decline in the structural diversity in forests within larger metropolitan cities. It is important to monitor the structural diversity at definite time intervals using effective technologies with a view to instituting the necessary conservation measures. The use of satellite images seems to be appropriate to this end. Here we aimed to identify the associations between the textural features derived from the satellite images with different spatial resolutions and the structural diversity indices in urban forest stands (Shannon-Wiener index, complexity index, dominance index and density of wildlife trees). RapidEye images with a spatial resolution of 5 m × 5 m, ASTER images with a spatial resolution of 15 m × 15 m and Landsat-8 ETM satellite images with a spatial resolution of 30 m × 30 m were used in this study. The first-order (standard deviation of gray levels) and second order (GLCM entropy, GLCM contrast and GLCM correlation) textural features were calculated from the satellite images. When associations between textural features in the images and the structural diversity indices were assessed using the Pearson correlation coefficient, very high associations were found between the image textural features and the diversity indices. The highest association was found between the standard deviation of gray levels (SDGL<sub>RAP</sub>) derived from RVI<sub>RAP</sub> of RapidEye image and the Shannon-Wiener index (H <sub>h</sub>) calculated on the basis of tree height (R <sup>2</sup> = 0.64). The findings revealed that RapidEye satellite images with a spatial resolution of 5 m × 5 m are most suitable for estimating the structural diversity in urban forests. 展开更多
关键词 BIODIVERSITY Satellite image structural diversity Texture measures Urban forests
下载PDF
Assess Medical Screening and Isolation Measures Based on Numerical Method for COVID-19 Epidemic Model in Japan 被引量:3
20
作者 Zhongxiang Chen Huijuan Zha +2 位作者 Zhiquan Shu Juyi Ye Jiaji Pan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第2期841-854,共14页
This study aims to improve control schemes for COVID-19 by a numerical model with estimation of parameters.We established a multi-level and multi-objective nonlinear SEIDR model to simulate the virus transmission.The ... This study aims to improve control schemes for COVID-19 by a numerical model with estimation of parameters.We established a multi-level and multi-objective nonlinear SEIDR model to simulate the virus transmission.The early spread in Japan was adopted as a case study.The first 96 days since the infection were divided into five stages with parameters estimated.Then,we analyzed the trend of the parameter value,age structure ratio,and the defined PCR test index(standardization of the scale of PCR tests).It was discovered that the self-healing rate and confirmed rate were linear with the age structure ratio and the PCR test index using the stepwise regression method.The transmission rates were related to the age structure ratio,PCR test index,and isolation efficiency.Both isolation measures and PCR test medical screening can effectively reduce the number of infected cases based on the simulation results.However,the strategy of increasing PCR test medical screening would encountered a bottleneck effect on the virus control when the index reached 0.3.The effectiveness of the policy would decrease and the basic reproduction number reached the extreme value at 0.6.This study gave a feasible combination for isolation and PCR test by simulation.The isolation intensity could be adjusted to compensate the insufficiency of PCR test to control the pandemic. 展开更多
关键词 SEIDR epidemic model multi-level and multi-objective problem PCR test index age structure isolation measure
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部