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Modeling Analysis of Factors Influencing Wind-Borne Seed Dispersal: A Case Study on Dandelion
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作者 Kemeng Xue 《American Journal of Plant Sciences》 CAS 2024年第4期252-267,共16页
A weed is a plant that thrives in areas of human disturbance, such as gardens, fields, pastures, waysides, and waste places where it is not intentionally cultivated. Dispersal affects community dynamics and vegetation... A weed is a plant that thrives in areas of human disturbance, such as gardens, fields, pastures, waysides, and waste places where it is not intentionally cultivated. Dispersal affects community dynamics and vegetation response to global change. The process of seed disposal is influenced by wind, which plays a crucial role in determining the distance and probability of seed dispersal. Existing models of seed dispersal consider wind direction but fail to incorporate wind intensity. In this paper, a novel seed disposal model was proposed in this paper, incorporating wind intensity based on relevant references. According to various climatic conditions, including temperate, arid, and tropical regions, three specific regions were selected to establish a wind dispersal model that accurately reflects the density function distribution of dispersal distance. Additionally, dandelions growth is influenced by a multitude of factors, encompassing temperature, humidity, climate, and various environmental variables that necessitate meticulous consideration. Based on Factor Analysis model, which completely considers temperature, precipitation, solar radiation, wind, and land carrying capacity, a conclusion is presented, indicating that the growth of seeds is primarily influenced by plant attributes and climate conditions, with the former exerting a relatively stronger impact. Subsequently, the remaining two plants were chosen based on seed weight, yielding consistent conclusion. 展开更多
关键词 Seed Dispersal Wind Intensity Climatic Effect Factor analysis Model
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Prototyping an open environment for sharing geographical analysis models on cloud computing platform 被引量:6
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作者 Yongning Wen Min Chen +3 位作者 Guonian Lu Hui Lin Li He Songshan Yue 《International Journal of Digital Earth》 SCIE EI 2013年第4期356-382,共27页
The sharing of geographical analysis models is of crucial importance for simulating geographic processes and phenomena in the current geographical information systems(e.g.Digital Earth),but there remain some issues th... The sharing of geographical analysis models is of crucial importance for simulating geographic processes and phenomena in the current geographical information systems(e.g.Digital Earth),but there remain some issues that have not been completely resolved.The challenges include,eliminating model heterogeneity and searching for suitable infrastructures to support the open sharing and effective execution of models.Taking advantage of cloud computing,this article aims to address the above issues and develop an open environment for geographical analysis model sharing.On the basis of the analysis of the applicability of cloud computing,the architecture of the open environment is proposed.More importantly,key strategies designed for heterogeneous model description,model encapsulating as well as model deploying and transparent accessing in the cloud are discussed in detail to establish such an environment.Finally,the prototype environment is implemented,and experiments were conducted to verify the environment’s feasibility to support the sharing of geographical analysis models. 展开更多
关键词 geographical analysis models cloud computing open environment
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A bibliometric analysis of research on nursing models in countries other than China
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作者 Shi-Fan Han Rui-Fang Zhu Lin Chen 《Chinese Nursing Research》 CAS 2017年第3期117-123,共7页
Objectives" To deepen our understanding of the status quo and to identify the hot topics and develop- mental trends of research on nursing models in countries other than China in the most recent decade. Methods: The... Objectives" To deepen our understanding of the status quo and to identify the hot topics and develop- mental trends of research on nursing models in countries other than China in the most recent decade. Methods: The study subjects were the publications retrieved from the PubMed database using the MeSH terms of "Models, Nursing". Bibliographic item co-occurrence mining system (BICOMS) software was used for conventional bibliometric analysis of publications during two time periods, 2005-2009 and 2010-2014. The number of published journal articles, journal distribution, authors of publications, country of origin of journals, and language of publications were analyzed to establish a high-frequency keyword profile and co-occurrence matrix. Graphical clustering toolkit (gCLUTO) software was applied for two-way clustering analysis and visualized analysis. Results: A total of 1472 journal articles with a key theme of nursing models were retrieved for final analysis, including 771 published during 2005-2009 and 701 during 2010-2014. The bibliometric analysis revealed that publications other than China concerning nursing models were mostly concentrated in the United States and the United Kingdom and that the number of relevant publications has been continuously decreasing. The two-way clustering analysis showed that there were mainly four types of research themes in the relevant publications in countries other than China during 2005-2009, i.e., nursing education and theoretical research, clinical nursing and psychological care, nursing administration, and models of nursing education, whereas there were five types during 2010-2014, i.e., nursing theories and clinical nursing practice, nursing administration models and assessments of nurses' knowledge and skills, community nursing administration models, nursing human resource management, and nursing education models and approaches. Conclusions: Research on nursing models in countries other than China is relatively mature and stable with a broader view, but it has shown a declining trend in recent years. It emphasizes both theory and practice, with research content tending to be structured into four modules, i.e., nursing education, administration, clinical practice, and theoretical research. Community nursing models may become a key research direction in the international research on nursing models in the future. 展开更多
关键词 Nursing models Bibliometrics Two-way clustering analysis Information visualization
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Transient pressure analysis of polymer flooding fractured wells with oil-water two-phase flow
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作者 WANG Yang YU Haiyang +2 位作者 ZHANG Jia FENG Naichao CHENG Shiqing 《Petroleum Exploration and Development》 2023年第1期175-182,共8页
The oil-water two-phase flow pressure-transient analysis model for polymer flooding fractured well is established by considering the comprehensive effects of polymer shear thinning,shear thickening,convection,diffusio... The oil-water two-phase flow pressure-transient analysis model for polymer flooding fractured well is established by considering the comprehensive effects of polymer shear thinning,shear thickening,convection,diffusion,adsorption retention,inaccessible pore volume and effective permeability reduction.The finite volume difference and Newton iteration methods are applied to solve the model,and the effects of fracture conductivity coefficient,injected polymer mass concentration,initial polymer mass concentration and water saturation on the well-test type curves of polymer flooding fractured wells are discussed.The results show that with the increase of fracture conductivity coefficient,the pressure conduction becomes faster and the pressure drop becomes smaller,so the pressure curve of transitional flow goes downward,the duration of bilinear flow becomes shorter,and the linear flow appears earlier and lasts longer.As the injected polymer mass concentration increases,the effective water phase viscosity increases,and the pressure loss increases,so the pressure and pressure derivative curves go upward,and the bilinear flow segment becomes shorter.As the initial polymer mass concentration increases,the effective water phase viscosity increases,so the pressure curve after the wellbore storage segment moves upward as a whole.As the water saturation increases,the relative permeability of water increases,the relative permeability of oil decreases,the total oil-water two-phase mobility becomes larger,and the pressure loss is reduced,so the pressure curve after the wellbore storage segment moves downward as a whole.The reliability and practicability of this new model are verified by the comparison of the results from simplified model and commercial well test software,and the actual well test data. 展开更多
关键词 fractured vertical well polymer flooding two-phase flow well test analysis model type curve influence factor
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An Application of Machine Learning to Thalassemia Diagnosis
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作者 Sitan Liu 《Journal of Computer and Communications》 2024年第2期211-230,共20页
Mediterranean anemia is a genetic disease that currently relies heavily on expert clinical experience to determine whether patients are affected. This method is overly reliant on expert experience and is not precise e... Mediterranean anemia is a genetic disease that currently relies heavily on expert clinical experience to determine whether patients are affected. This method is overly reliant on expert experience and is not precise enough. This paper proposes two modeling methods to predict whether patients have Mediterranean anemia. The first method involves using Principal Component Analysis (PCA) to reduce the dimensionality of the data, followed by logistic regression modeling (PCA-LR) on the reduced dataset. The second method involves building a Partial Least Squares Regression (PLS) model. Experimental results show that the prediction accuracy of the PCA-LR model is 87.5% (degree = 2, λ=4), and the prediction accuracy of the PLS model is 92.5% (ncomp = 4), indicating good predictive performance of the models. 展开更多
关键词 MULTICOLLINEARITY Statistical analysis models Data Mining PCA-LR PLS
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Experimental Study and Model Analysis of the Performance of IPMC Membranes with Various Thickness 被引量:12
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作者 Qingsong He Min Yu +3 位作者 Linlin Song Haitao Ding Xiaoqing Zhang Zhendong Dai 《Journal of Bionic Engineering》 SCIE EI CSCD 2011年第1期77-85,共9页
Ionic Polymer-Metal Composite (IPMC) is a new electro-active polymer, which has the advantages of light weight, flexibility, and large stroke with low driving voltage. Because of these features, IPMC can be applied ... Ionic Polymer-Metal Composite (IPMC) is a new electro-active polymer, which has the advantages of light weight, flexibility, and large stroke with low driving voltage. Because of these features, IPMC can be applied to bionic robotic actuators, artificial muscles, as well as dynamic sensors. However, IPMC has the major drawback of low generative blocking force. In this paper, in order to enhance the blocking force, the Nation membranes with thickness of 0.22 mm, 0.32 mm, 0.42 mm, 0.64 mm and 0.8 mm were prepared by casting from liquid solution. By employing these Nation membranes, IPMCs with varying thickness were fabricated by electroless plating. The elastic modulus of the casted Nation membranes were obtained by a nano-indenter, and the current, the displacement and the blocking force were respectively measured by the apparatus for actuation test. Finally, the effects of the thickness on the performance of IPMC were analyzed with an electromechanical model. Experimental study and theory analysis indicate that as the thickness increases, the elastic modulus of Nation membrane and the blocking force of IPMC increase, however, the current and the displacement decrease. 展开更多
关键词 IPMC Nation membranes electroless plating actuation test model analysis
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Comprehensive security risk factor identification for small reservoirs with heterogeneous data based on grey relational analysis model 被引量:6
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作者 Jing-chun Feng Hua-ai Huang +1 位作者 Yao Yin Ke Zhang 《Water Science and Engineering》 EI CAS CSCD 2019年第4期330-338,共9页
Identification of security risk factors for small reservoirs is the basis for implementation of early warning systems.The manner of identification of the factors for small reservoirs is of practical significance when ... Identification of security risk factors for small reservoirs is the basis for implementation of early warning systems.The manner of identification of the factors for small reservoirs is of practical significance when data are incomplete.The existing grey relational models have some disadvantages in measuring the correlation between categorical data sequences.To this end,this paper introduces a new grey relational model to analyze heterogeneous data.In this study,a set of security risk factors for small reservoirs was first constructed based on theoretical analysis,and heterogeneous data of these factors were recorded as sequences.The sequences were regarded as random variables,and the information entropy and conditional entropy between sequences were measured to analyze the relational degree between risk factors.Then,a new grey relational analysis model for heterogeneous data was constructed,and a comprehensive security risk factor identification method was developed.A case study of small reservoirs in Guangxi Zhuang Autonomous Region in China shows that the model constructed in this study is applicable to security risk factor identification for small reservoirs with heterogeneous and sparse data. 展开更多
关键词 Security risk factor identification Heterogeneous data Grey relational analysis model Relational degree Information entropy Conditional entropy Small reservoir GUANGXI
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Nonlinear Dynamic Analysis of Flexible Marine-Risers 被引量:2
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作者 Chen Jiajing and Wang Dongjiao Professor, South China University of Technology, Guangzhou PhD Student, Hong Kong Polytechnic Formerly, South China University of Technology, Guangzhou 《China Ocean Engineering》 SCIE EI 1991年第4期373-384,共12页
A nonlinear dynamic analysis model is estabilished on the basis of 'lumped mass' approach, which takes the influence of the fluid flow within the pipe into consideration. Numerical results are compared with th... A nonlinear dynamic analysis model is estabilished on the basis of 'lumped mass' approach, which takes the influence of the fluid flow within the pipe into consideration. Numerical results are compared with the published works, and the effects of internal fluid flow, internal pressure, dyanmics as well as the nonlinear characteristics on the behavior of flexible risers are discussed. From this work, some useful conclusions are drawn. 展开更多
关键词 flexible riser nonlinear dynamic analysis model irregular wave oilfield exploitation
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An Emotion Analysis Method Using Multi-Channel Convolution Neural Network in Social Networks 被引量:2
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作者 Xinxin Lu Hong Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第10期281-297,共17页
As an interdisciplinary comprehensive subject involving multidisciplinary knowledge,emotional analysis has become a hot topic in psychology,health medicine and computer science.It has a high comprehensive and practica... As an interdisciplinary comprehensive subject involving multidisciplinary knowledge,emotional analysis has become a hot topic in psychology,health medicine and computer science.It has a high comprehensive and practical application value.Emotion research based on the social network is a relatively new topic in the field of psychology and medical health research.The text emotion analysis of college students also has an important research significance for the emotional state of students at a certain time or a certain period,so as to understand their normal state,abnormal state and the reason of state change from the information they wrote.In view of the fact that convolutional neural network cannot make full use of the unique emotional information in sentences,and the need to label a large number of highquality training sets for emotional analysis to improve the accuracy of the model,an emotional analysismodel using the emotional dictionary andmultichannel convolutional neural network is proposed in this paper.Firstly,the input matrix of emotion dictionary is constructed according to the emotion information,and the different feature information of sentences is combined to form different network input channels,so that the model can learn the emotion information of input sentences from various feature representations in the training process.Then,the loss function is reconstructed to realize the semi supervised learning of the network.Finally,experiments are carried on COAE 2014 and self-built data sets.The proposed model can not only extract more semantic information in emotional text,but also learn the hidden emotional information in emotional text.The experimental results show that the proposed emotion analysis model can achieve a better classification performance.Compared with the best benchmark model gram-CNN,the F1 value can be increased by 0.026 in the self-built data set,and it can be increased by 0.032 in the COAE 2014 data set. 展开更多
关键词 Emotion analysis model emotion dictionary convolution neural network semi supervised learning deep learning pooling feature feature mapping
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Parameter identification and global sensitivity analysis of Xin'anjiang model using meta-modeling approach 被引量:12
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作者 Xiao-meng SONG Fan-zhe KONG +2 位作者 Che-sheng ZHAN Ji-wei HAN Xin-hua ZHANG 《Water Science and Engineering》 EI CAS CSCD 2013年第1期1-17,共17页
Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity ana... Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity analysis of hydrological model is a key step in model uncertainty quantification, which can identify the dominant parameters, reduce the model calibration uncertainty, and enhance the model optimization efficiency. There are, however, some shortcomings in classical approaches, including the long duration of time and high computation cost required to quantitatively assess the sensitivity of a multiple-parameter hydrological model. For this reason, a two-step statistical evaluation framework using global techniques is presented. It is based on (1) a screening method (Morris) for qualitative ranking of parameters, and (2) a variance-based method integrated with a meta-model for quantitative sensitivity analysis, i.e., the Sobol method integrated with the response surface model (RSMSobol). First, the Morris screening method was used to qualitatively identify the parameters' sensitivity, and then ten parameters were selected to quantify the sensitivity indices. Subsequently, the RSMSobol method was used to quantify the sensitivity, i.e., the first-order and total sensitivity indices based on the response surface model (RSM) were calculated. The RSMSobol method can not only quantify the sensitivity, but also reduce the computational cost, with good accuracy compared to the classical approaches. This approach will be effective and reliable in the global sensitivity analysis of a complex large-scale distributed hydrological model. 展开更多
关键词 Xin'anjiang model global sensitivity analysis parameter identification meta-modeling approach response surface model
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Accuracy Analysis and Design of A3 Parallel Spindle Head 被引量:8
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作者 NI Yanbing ZHANG Biao +1 位作者 SUN Yupeng ZHANG Yuan 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第2期239-249,共11页
As functional components of machine tools, parallel mechanisms are widely used in high efficiency machining of aviation components, and accuracy is one of the critical technical indexes. Lots of researchers have focus... As functional components of machine tools, parallel mechanisms are widely used in high efficiency machining of aviation components, and accuracy is one of the critical technical indexes. Lots of researchers have focused on the accuracy problem of parallel mechanisms, but in terms of controlling the errors and improving the accuracy in the stage of design and manufacturing, further efforts are required. Aiming at the accuracy design of a 3-DOF parallel spindle head(A3 head), its error model, sensitivity analysis and tolerance allocation are investigated. Based on the inverse kinematic analysis, the error model of A3 head is established by using the first-order perturbation theory and vector chain method. According to the mapping property of motion and constraint Jacobian matrix, the compensatable and uncompensatable error sources which affect the accuracy in the end-effector are separated. Furthermore, sensitivity analysis is performed on the uncompensatable error sources. The sensitivity probabilistic model is established and the global sensitivity index is proposed to analyze the influence of the uncompensatable error sources on the accuracy in the end-effector of the mechanism. The results show that orientation error sources have bigger effect on the accuracy in the end-effector. Based upon the sensitivity analysis results, the tolerance design is converted into the issue of nonlinearly constrained optimization with the manufacturing cost minimum being the optimization objective. By utilizing the genetic algorithm, the allocation of the tolerances on each component is finally determined. According to the tolerance allocation results, the tolerance ranges of ten kinds of geometric error sources are obtained. These research achievements can provide fundamental guidelines for component manufacturing and assembly of this kind of parallel mechanisms. 展开更多
关键词 A3 head error model sensitivity analysis tolerance allocation
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Assessment of pipeline stability in the Gulf of Mexico during hurricanes using dynamic analysis 被引量:3
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作者 Yinghui Tian Bassem Youssef Mark J.Cassidy 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2015年第2期74-79,共6页
Pipelines are the critical link between major offshore oil and gas developments and the mainland. Any inadequate on-bottom stability design could result in disruption and failure, having a devastating impact on the ec... Pipelines are the critical link between major offshore oil and gas developments and the mainland. Any inadequate on-bottom stability design could result in disruption and failure, having a devastating impact on the economy and environment. Predicting the stability behavior of offshore pipelines in hurricanes is therefore vital to the assessment of both new design and existing assets. The Gulf of Mexico has a very dense network of pipeline systems constructed on the seabed. During the last two decades, the Gulf of Mexico has experienced a series of strong hurricanes, which have destroyed, disrupted and destabilized many pipelines. This paper first reviews some of these engineering cases. Following that, three case studies are retrospectively simulated using an in-house developed program. The study utilizes the offshore pipeline and hurricane details to conduct a Dynamic Lateral Stability analysis, with the results providing evidence as to the accuracy of the modeling techniques developed. 展开更多
关键词 Pipeline On-bottom stability Dynamic lateral stability analysis Force-resultant model Hydrodynamic load
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Effects of modeling means on properties of monitoring models of spot welding quality 被引量:2
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作者 张忠典 李冬青 +1 位作者 赵洪运 于燕 《China Welding》 EI CAS 2002年第2期119-123,共5页
Analyzing and modeling the relation between monitoring information during welding and quality information of the joints is the foundation of monitoring resistance spot welding quality. According to the means of modeli... Analyzing and modeling the relation between monitoring information during welding and quality information of the joints is the foundation of monitoring resistance spot welding quality. According to the means of modeling, the known models can be divided into three large categories: single linear regression models, multiple linear regression models and multiple non linear models. By modeling the relations between dynamic resistance information and welding quality parameters with different means, this paper analyzes effects of modeling means on performances of monitoring models of resistance spot welding quality. From the test results, the following conclusions can be drawn: By comparison with two other kinds of models, artificial neural network (ANN) model can describe non linear and high coupling relationship between monitoring information and quality information more reasonably, improve performance of monitoring model remarkably, and make the estimated values of welding quality parameters more accurate and reliable. 展开更多
关键词 spot welding quality monitoring model regression analysis artificial neural networks
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Analysis of Frequency Characteristics and Sensitivity of Compliant Mechanisms 被引量:7
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作者 LIU Shanzeng DAI Jiansheng +3 位作者 LI Aimin SUN Zhaopeng FENG Shizhe CAO Guohua 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第4期680-693,共14页
Based on a modified pseudo-rigid-body model,the frequency characteristics and sensitivity of the large-deformation compliant mechanism are studied.Firstly,the pseudo-rigid-body model under the static and kinetic condi... Based on a modified pseudo-rigid-body model,the frequency characteristics and sensitivity of the large-deformation compliant mechanism are studied.Firstly,the pseudo-rigid-body model under the static and kinetic conditions is modified to enable the modified pseudo-rigid-body model to be more suitable for the dynamic analysis of the compliant mechanism.Subsequently,based on the modified pseudo-rigid-body model,the dynamic equations of the ordinary compliant four-bar mechanism are established using the analytical mechanics.Finally,in combination with the finite element analysis software ANSYS,the frequency characteristics and sensitivity of the compliant mechanism are analyzed by taking the compliant parallel-guiding mechanism and the compliant bistable mechanism as examples.From the simulation results,the dynamic characteristics of compliant mechanism are relatively sensitive to the structure size,section parameter,and characteristic parameter of material on mechanisms.The results could provide great theoretical significance and application values for the structural optimization of compliant mechanisms,the improvement of their dynamic properties and the expansion of their application range. 展开更多
关键词 compliant mechanism pseudo-rigid-body model frequency characteristic sensitivity analysis finite element analysis
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Association between Macroscopic-factors and Identified HIV/AIDS Cases among Injecting Drug Users: An Analysis Using Geographically Weighted Regression Model 被引量:1
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作者 XING Jian Nan GUO Wei +5 位作者 QIAN Sha Sha DING Zheng Wei CHEN Fang Fang PENG Zhi Hang QIN Qian Qian WANG Lu 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2014年第4期311-318,共8页
Drug use (DU), particularly injecting drug use (IDU) has been the main route of transmission and spread of Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDSJ among injecting drug use... Drug use (DU), particularly injecting drug use (IDU) has been the main route of transmission and spread of Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDSJ among injecting drug users (IDUs)[1]. Previous studies have proven that needles or cottons sharing during drug injection were major risk factors for HIV/AIDS transmission at the personal level[z4]. Being a social behavioral issue, HIV/AIDS related risk factors should be far beyond the personal level. Therefore, studies on HIV/AIDS related risk factors should focus not only on the individual factors, but also on the association between HIV/AIDS cases and macroscopic-factors, such as economic status, transportation, health care services, etc[1]. The impact of the macroscopic-factors on HIV/AIDS status might be either positive or negative, which are potentially reflected in promoting, delaying or detecting HIV/AIDS epidemics. 展开更多
关键词 AIDS HIV An analysis Using Geographically Weighted Regression Model
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An empirical analysis on community residents' perception and major influencing factors of rural tourism development 被引量:2
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作者 WEI Lang-jie YAN Zhao-nan +1 位作者 LI Kai-li GU Ya-qing 《Ecological Economy》 2021年第3期176-185,共10页
With the rapid development of rural tourism in China,community residents,as important stakeholders in the development of rural tourism,their perceptions and attitudes directly affect the sustainable and healthy develo... With the rapid development of rural tourism in China,community residents,as important stakeholders in the development of rural tourism,their perceptions and attitudes directly affect the sustainable and healthy development of local rural tourism.Taking the community residents of Xiaogucheng Village in Hangzhou as the research object,using the methods of field interviews and questionnaires,a multiple regression model was established to conduct an empirical analysis on the perception and main factors affecting the development of rural tourism of community residents.The results show that the development of rural tourism in villages with better economic development is not as popular as expected;Where community residents have made ideological progress and are willing to participate in tourism development,the development effect of rural tourism is remarkable;In addition,community residents also hope that their personal abilities can be combined with rural tourism for common development;The destruction of community environment has a slight impact on the development of rural tourism,which shows that the attention is not enough.Finally,based on the analysis conclusion,it provides new ideas and inspiration for the sustainable development of rural tourism:improving the community residents’participation in rural tourism system,establishing the guidance mechanism of community residents’tourism vocational education,and consolidating the achievements of community ecological environment management. 展开更多
关键词 rural tourism community residents’perception multiple regression analysis model
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Safety analysis of wheel brake system based on STAMP/STPA and Monte Carlo simulation 被引量:7
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作者 HU Jianbo ZHENG Lei XU Shukui 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第6期1327-1339,共13页
The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with ... The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with traditional probability techniques based on the linear chain of events. However, it could not comprehensively analyze system safety problems, especially in operating environment, interaction of subsystems, and human factors. Thus,we consider system safety as a control problem based on the system-theoretic accident model, the processes(STAMP) model and the system theoretic process analysis(STPA) technique to compensate the deficiency of traditional techniques. Meanwhile,system safety simulation is considered as system control simulation, and Monte Carlo methods are used which consider the range of uncertain parameters and operation deviation to quantitatively study system safety influence factors in control simulation. Firstly,we construct the STAMP model and STPA feedback control loop of the wheel brake system based on the system functional requirement. Then four unsafe control actions are identified, and causes of them are analyzed. Finally, we construct the Monte Carlo simulation model to analyze different scenarios under disturbance. The results provide a basis for choosing corresponding process model variables in constructing the context table and show that appropriate brake strategies could prevent hazards in aircraft landing taxiing. 展开更多
关键词 safety analysis landing taxiing system-theoretic accident model and processes(STAMP) model and system theoretic process analysis(STPA)(STAMP/STPA) feedback control loop Monte Carlo simulation
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Analysis of sp Pillar Stability Experiment: Continuous thermo-mechanical model development and calibration 被引量:1
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作者 R. Blaheta P. Byczanski +5 位作者 M. ermák R. Hrtus R. Kohut A. Kolcun J. Malík S. Sysala 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2013年第2期124-135,共12页
The paper describes an analysis of thermo-mechanical (TM) processes appearing during the Aspo Pillar Stability Experiment (APSE). This analysis is based on finite elements with elasticity, plasticity and dam- age ... The paper describes an analysis of thermo-mechanical (TM) processes appearing during the Aspo Pillar Stability Experiment (APSE). This analysis is based on finite elements with elasticity, plasticity and dam- age mechanics models of rock behaviour and some least squares calibration techniques. The main aim is to examine the capability of continuous mechanics models to predict brittle damage behaviour of gran- ite rocks. The performed simulations use an in-house finite element software GEM and self-developed experimental continuum damage MATLAB code. The main contributions are twofold. First, it is an inverse analysis, which is used for (1) verification of an initial stress measurement by back analysis of conver- gence measurement during construction of the access tunnel and (2) identification of heat transfer rock mass properties by an inverse method based on the known heat sources and temperature measurements. Second, three different hierarchically built models are used to estimate the pillar damage zones, i.e. elas- tic model with Drucker-Prager strength criterion, elasto-plastic model with the same yield limit and a combination of elasto-plasticity with continuum damage mechanics. The damage mechanics model is also used to simulate uniaxial and triaxial compressive strength tests on the ,Aspo granite. 展开更多
关键词 In situ pillar stability experiment Continuous mechanics Damage of granite rocks Model calibration by back analysis Finite element method (FEM)
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Parameters Sensitivity Analysis and Correction for Concrete Damage Plastic Model 被引量:1
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作者 Yaqin Jiang Pengfei Xu +1 位作者 Chengzhi Wang Dianshu Liu 《Journal of Beijing Institute of Technology》 EI CAS 2018年第1期103-108,共6页
In order to understand the effect of hardening ductility parameters and softening ductility parameters of the concrete damage plastic model in LS-DYNA,a sensitivity and reliability analysis of these parameters through... In order to understand the effect of hardening ductility parameters and softening ductility parameters of the concrete damage plastic model in LS-DYNA,a sensitivity and reliability analysis of these parameters through a convenient cube unit test was conducted. The results showed that the peak strength strain was independent of the hardening ductility parameter DH,but affected by AH,BH,and CH. The softening ductility was mainly related to the softening ductility parameter AS,but not affected by the damage ductility exponent BS. In case that the model with default parameters failed to match the AS-controlled damage softening phase,an optimized model with an AS correction was developed. The corrected model with the AS value of 2 matched well with the code model,and exhibited good feasibility in predicting the stress-strain curve of different grades of concrete. Moreover,the practicability of the corrected model was further validated by the conventional triaxial test. The simulated curve exhibited favorable consistence with the trial curve. Therefore,the model with parameter correction could provide a prospective reference for predicting the mechanical properties of concrete. 展开更多
关键词 damage-plastic model concrete sensitivity analysis parameter correction
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A Multifractal Detrended Fluctuation Analysis of the Ising Financial Markets Model with Small World Topology 被引量:1
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作者 张昂辉 李晓温 +1 位作者 苏桂锋 张一 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第9期13-16,共4页
We present a multifractal detrended fluctuation analysis (MFDFA) of the time series of return generated by our recently-proposed Ising financial market model with underlying small world topology. The result of the M... We present a multifractal detrended fluctuation analysis (MFDFA) of the time series of return generated by our recently-proposed Ising financial market model with underlying small world topology. The result of the MFDFA shows that there exists obvious multifractal scaling behavior in produced time series. We compare the MFDFA results for original time series with those for shuffled series, and find that its multifractal nature is due to two factors: broadness of probability density function of the series and different correlations in small- and large-scale fluctuations. This may provide new insight to the problem of the origin of multifractality in financial time series. 展开更多
关键词 A Multifractal Detrended Fluctuation analysis of the Ising Financial Markets Model with Small World Topology
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