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Space-time analysis of the changing patterns of population pressure on the ecological environment in China 被引量:1
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作者 Dongqi Sun Jinliang Jiang +2 位作者 Jianbin Xu Liang Zhou Yi Hu 《Chinese Journal of Population,Resources and Environment》 2015年第4期341-348,共8页
This paper examines the temporal change and spatial variation of population pressure on the ecological environment in China.We have collected sufficient data from the statistical yearbooks of 31 provincial administrat... This paper examines the temporal change and spatial variation of population pressure on the ecological environment in China.We have collected sufficient data from the statistical yearbooks of 31 provincial administrative areas in 1990,1995,2000,2005,and 2010.Using a geographic information system(GIS) and relevant models,we analyzed the trend of the population pressure on ecological environment and the change of the gravity center of ecological environment quality.We conclude that:(1) generally,population pressure on the ecological environment in China was becoming higher during1990-2010,especially in some areas where the population and environment were in serious imbalance and the ecological environment experienced severe pollution;(2) during a certain period,population pressure on the ecological environment was becoming lower in some areas,but the ecological environment was getting worse;(3) the areas with super-high population pressure on the ecological environment were Beijing,Tianjin,and Shanghai;(4) the gravity center of population pressure on the ecological environment and the center of ecological environment quality move differently during the study time period,but the general trend was similar- both of them were moving from west to east.Based on the analysis,this paper also provides some policy suggestions on the control of ecological environment quality. 展开更多
关键词 Chinese POPULATION ECO-ENVIRONMENT ECO-ENVIRONMENTAL pressure CHANGING TREND space-time analysis
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Genome-wide characterization and expression analysis of the cultivated peanut AhPR10 gene family mediating resistance to Aspergillus flavus
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作者 Qi Zhao Mengjie Cui +11 位作者 Tengda Guo Lei Shi Feiyan Qi Ziqi Sun Pei Du Hua Liu Yu Zhang Zheng Zheng Bingyan Huang Wenzhao Dong Suoyi Han Xinyou Zhang 《Journal of Integrative Agriculture》 2026年第1期56-67,共12页
The pathogenesis-related protein PR10 plays a vital role in plant growth,development,and stress responses.This study systematically identified and analyzed PR10 genes in cultivated peanut(Arachis hypogaea L.),examinin... The pathogenesis-related protein PR10 plays a vital role in plant growth,development,and stress responses.This study systematically identified and analyzed PR10 genes in cultivated peanut(Arachis hypogaea L.),examining their phylogenetic relationships,conserved motifs,gene structures,and syntenic relationships.The analysis identified 54 Ah PR10 genes,which were classified into eight groups based on phylogenetic relationships,supported by gene structure and conserved motif characterization.Analysis of chromosomal distribution and synteny demonstrated that segmental duplications played a crucial role in the expansion of the Ah PR10 gene family.The identified Ah PR10 genes exhibited both constitutive and inducible expression patterns.Significantly,Ah PR10-7,Ah PR10-33,and Ah PR10-41 demonstrated potential importance in peanut resistance to Aspergillus flavus.In vitro fungistatic experiments demonstrated that recombinant Ah PR10-33 effectively inhibited A.flavus mycelial growth.These findings provide valuable insights for future investigations into Ah PR10 functions in protecting peanut from A.flavus infection. 展开更多
关键词 cultivated peanut PR10 phylogenetic analysis expression pattern Aspergillus avus
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Tissue Expression Pattern and Bioinformatics Analysis of OsKMP2 Gene in Rice
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作者 Jiaqi DING Ziang YI +2 位作者 Qi QIU Chenzhong JIN Taoli LIU 《Agricultural Biotechnology》 2025年第3期1-5,共5页
Kinesins are a superfamily of proteins widely present in eukaryotes,playing crucial roles in plant cell wall assembly,cell elongation regulation,gravity sensing,and fertility control.In this study,bioinformatics analy... Kinesins are a superfamily of proteins widely present in eukaryotes,playing crucial roles in plant cell wall assembly,cell elongation regulation,gravity sensing,and fertility control.In this study,bioinformatics analysis of the OsKMP2 gene(LOC_Os02g28850)was performed using online tools such as ExPASy-ProtParam,ProtScale,CD-search,and DNAMAN software.Additionally,qRT-PCR was employed to analyze the tissue expression pattern of OsKMP2.The results showed that the molecular weight of the OsKMP2 is 118.39728 kDa,and it is a hydrophilic and unstable acidic protein.Secondary structure prediction revealed that it primarily consists ofα-helices(69.45%),random coils(25.19%),and extended strands(5.36%).The gene was expressed in various rice tissues,with the highest expression level observed in leaves.These results indicate that the OsKMP2 gene exhibits high evolutionary conservation and functional diversity in rice. 展开更多
关键词 RICE OsKMP Tissue expression pattern Bioinformatics analysis
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A PRELIMINARY STUDY ON THE 3DVAR ASSIMILATION OF THE AMSU-A DATA IN SPACE-TIME MULTISCALE ANALYSIS SYSTEM 被引量:4
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作者 LIU Rui-xia XIE Yuan-fu LIU Jie 《Journal of Tropical Meteorology》 SCIE 2017年第3期314-322,共9页
Assimilating satellite radiances into Numerical Weather Prediction(NWP) models has become an important approach to increase the accuracy of numerical weather forecasting. In this study, the assimilation technique sche... Assimilating satellite radiances into Numerical Weather Prediction(NWP) models has become an important approach to increase the accuracy of numerical weather forecasting. In this study, the assimilation technique scheme was employed in NOAA's STMAS(Space-Time Multiscale Analysis System) to assimilate AMSU-A radiances data.Channel selection sensitivity experiments were conducted on assimilated satellite data in the first place. Then, real case analysis of AMSU-A data assimilation was performed. The analysis results showed that, following assimilating of AMSU-A channels 5-11 in STMAS, the objective function quickly converged, and the channel vertical response was consistent with the AMSU-A weighting function distribution, which suggests that the channels can be used in the assimilation of satellite data in STMAS. With the case of the Typhoon Morakot in Taiwan Island in August 2009 as an example, experiments on assimilated and unassimilated AMSU-A radiances data were designed to analyze the impact of the assimilation of satellite data on STMAS. The results demonstrated that assimilation of AMSU-A data provided more accurate prediction of the precipitation region and intensity, and especially, it improved the 0-6h precipitation forecast significantly. 展开更多
关键词 MULTIGRID 3DVAR space-time multiscale analysis system numerical experiments
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Space-Time Cluster Analysis of Tuberculosis Incidence in Beijing, China
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作者 Gehendra Mahara Mina Karki +3 位作者 Kun Yang Sipeng Chen Wei Wang Xiuhua Guo 《Journal of Tuberculosis Research》 2018年第4期302-319,共18页
Tuberculosis is one of the top killer diseases in the globe. The aim of this study was to explore the geographic distribution patterns and clustering characteristics of the disease incidence in terms of both space and... Tuberculosis is one of the top killer diseases in the globe. The aim of this study was to explore the geographic distribution patterns and clustering characteristics of the disease incidence in terms of both space and time with high relative risk locations for tuberculosis incidence in Beijing area. A retrospective space-time clustering analysis was conducted at the districts level in Beijing area based on reported cases of sputum smear-positive pulmonary tuberculosis (TB) from 2005 to 2014. Global and local Moran’s I, autocorrelation analysis along with Ord (Gi*) statistics was applied to detect spatial patterns and the hotspot of TB incidence. Furthermore, the Kuldorff’s scan statistics were used to analyze space-time clusters. A total of 40,878 TB cases were reported in Beijing from 2005 to 2014. The annual average incidence rate was 22.11 per 100,000 populations (ranged from 16.55 to 25.71). The seasonal incidence occurred from March to July until late autumn. A higher relative risk area for TB incidence was mainly detected in urban and some rural districts of Beijing. The significant most likely space-time clusters and secondary clusters of TB incidence were scattered diversely in Beijing districts in each study year. The risk population was mainly scattered in urban and dense populated districts, including in few rural districts. 展开更多
关键词 TUBERCULOSIS SPATIAL STATISTICS space-time analysis BEIJING China
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Correspondence Analysis on a Space-Time Data Set for Multiple Environmental Variables
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作者 Palma Monica 《International Journal of Geosciences》 2015年第10期1154-1165,共12页
Applications of the multivariate technique called correspondence analysis for environmental studies are relatively new and are limited to spatial multivariate data set. In this paper, a procedure of applying correspon... Applications of the multivariate technique called correspondence analysis for environmental studies are relatively new and are limited to spatial multivariate data set. In this paper, a procedure of applying correspondence analysis to a large space-time data set for multiple environmental variables is shown. In particular, nitrogen dioxide and carbon monoxide hourly concentrations measured during January 1999 at several monitored stations in a district of Northern Italy are analyzed. The procedure consists in transforming the continuous variables into categorical ones by the means of appropriate indicator variables, generating special contingency tables and applying correspondence analysis. The use of this classical multivariate technique allows the identification of important relationships among pollution levels and monitoring stations and/or relationships among pollution levels and observation times. 展开更多
关键词 space-time DATA INDICATOR TRANSFORM CORRESPONDENCE analysis
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Space-Time Analysis of Foot-and-Mouth Disease from 2005 to 2014 among Cattle Populations in Benin:A Retrospective Study
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作者 Nestor Noudeke Evelyne Houndje +3 位作者 Olivier Zannou Ignace Dotche Issaka Youssao Souaibou Farougou 《Open Journal of Animal Sciences》 2017年第1期30-44,共15页
Many cases of foot-and-mouth disease (FMD) are reported every year in Benin. In order to elucidate the epidemiology of this disease, a space-time analysis was carried out in all the 77 municipalities of the country ai... Many cases of foot-and-mouth disease (FMD) are reported every year in Benin. In order to elucidate the epidemiology of this disease, a space-time analysis was carried out in all the 77 municipalities of the country aiming to identify high risk areas as well as risk factors such as season and transhumance on the period of 2005 to 2014. Data were collected retrospectively from the Directory of Animal Production of Benin. The method of Kulldorff was used with the software SaTScanTM for the space-time analysis while a script was designed in the software R to generate new sizes with three different models of transhumance. From 2005 to 2014, 434 foci were recorded. Many outbreaks occurred in August, September and October. This period corresponds to the small rainy season in the South and the rainy season of the North. The municipality of Parakou was regarded as the source FMD outbreaks in Benin because it hosts one of the largest livestock markets in the country and many rivers. It was the municipality at the highest risk. The other municipalities at risk were Nikki, Pèrèrè and Kalaléas well as Karimama (hosting the national parkW), Kouandé and Toucountouna located nearby Pendjari’s national park. This study revealed that the space-time configuration is real and the main factors of persistence and dissemination of FMD virus were national parks, classified forests and the livestock market of Parakou all located in the North. The variation of the number of cattle due to their transhumance from the North to the South did not influence the zones at risk. Therefore, Northern Benin is probably at high risk of FMD. 展开更多
关键词 BENIN Foot-and-Mouth Disease Zone at Risk space-time analysis TRANSHUMANCE
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Application of support vector machine in trip chaining pattern recognition and analysis of explanatory variable effects 被引量:2
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作者 杨硕 邓卫 程龙 《Journal of Southeast University(English Edition)》 EI CAS 2017年第1期106-114,共9页
In order to improve the accuracy of travel demand forecast and considering the distribution of travel behaviors within time dimension, a trip chaining pattern recognition model was established based on activity purpos... In order to improve the accuracy of travel demand forecast and considering the distribution of travel behaviors within time dimension, a trip chaining pattern recognition model was established based on activity purposes by applying three methods: the support vector machine (SVM) model, the radial basis function neural network (RBFNN) model and the multinomial logit (MNL) model. The effect of explanatory factors on trip chaining behaviors and their contribution to model performace were investigated by sensitivity analysis. Results show that the SVM model has a better performance than the RBFNN model and the MNL model due to its higher overall and partial accuracy, indicating its recognition advantage under a smai sample size scenario. It is also proved that the SVM model is capable of estimating the effect of multi-category factors on trip chaining behaviors more accurately. The different contribution of explanatory, factors to trip chaining pattern recognition reflects the importance of refining trip chaining patterns ad exploring factors that are specific to each pattern. It is shown that the SVM technology in travel demand forecast modeling and analysis of explanatory variable effects is practical. 展开更多
关键词 trip chaining patterns support vector machine recognition performance sensitivity analysis
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Quantitative Analysis of Land Use Landscape Pattern in Shihezi Desert Oasis
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作者 王玲 吕新 高秀平 《Journal of Landscape Research》 2009年第3期49-54,81,共7页
Based on the land use status map of Shihezi City,the land use landscape map of Shihezi City was made with the support of GIS then many landscape indices were selected to quantitatively analyze the landscape pattern ch... Based on the land use status map of Shihezi City,the land use landscape map of Shihezi City was made with the support of GIS then many landscape indices were selected to quantitatively analyze the landscape pattern characteristics of Shihezi Oasis from three aspects of landscape diversity index,landscape space configuration index and plaque characteristics index. The results showed that the main plaque types of the landscape in Shihezi reclamation area are arable land and water areas,which totally account for 58% of the total area; farmland,gardens,woodland,urban sites,industrial and mining land use were embedded in this oasis landscape in the form of mosaics,and their fractal index was high due to the strong impact of human activities; arable land and mining land distribution was scattered,but marshes and other uncultivated land were relatively concentrated. The dominance degree of the landscape was low because there was no advantageous type in this landscape and all patches distributed equably which was easily to be disturbed so that the whole landscape was unstable. Comprehensively speaking,the landscape in Shihezi region was rather complicate,and its diversity index,fragmentation degree and heterogeneity were high. 展开更多
关键词 Shihezi RECLAMATION area DESERT OASIS LANDSCAPE pattern LANDSCAPE index QUANTITATIVE analysis
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Gradient Analysis of Land Utilization and Landscape Pattern Based on the Buffer Zone in South Guangzhou City
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作者 曲林静 杨木壮 《Journal of Landscape Research》 2009年第9期44-47,58,共5页
Under the background of the 'Southwardly Development' of Guangzhou City,this paper chooses Panyu District as the research object and uses the 2005 land use data to quantitatively analyze the landscape layout a... Under the background of the 'Southwardly Development' of Guangzhou City,this paper chooses Panyu District as the research object and uses the 2005 land use data to quantitatively analyze the landscape layout and its change in the study area based on the support of GIS and Fragstats through combining landscape index and gradient analysis.The results show that it is feasible to show urbanization and the change of the spatial pattern of urban landscape through utilizing gradient analysis and landscape index.Over the course of 'Southwardly Development',the urbanization level of Panyu District has been enhanced unceasingly.And the landscape spatial patterns of different land uses and their variation characteristics are obviously different. 展开更多
关键词 GRADIENT analysis GIS LANDSCAPE pattern LANDSCAPE INDEX
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Lateral load pattern in pushover analysis 被引量:8
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作者 孙景江 Tetsuro Ono +1 位作者 赵衍刚 王威 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2003年第1期99-108,共10页
The seismic capacity curves of three types of buildings including frame,frame-shear wall and shear wall ob- tained by pushover analysis under different lateral load patterns are compared with those from nonlinear time... The seismic capacity curves of three types of buildings including frame,frame-shear wall and shear wall ob- tained by pushover analysis under different lateral load patterns are compared with those from nonlinear time history analy- sis.Based on the numerical results obtained a two-phase load pattern:an inverted triangle(first mode)load pattern until the base shear force reaches β times its maximum value,V_(max)followed by a(x/H)~α form,here β and α being some coeffi- cients depending on the type of the structures considered,is proposed in the paper,which can provide excellent approxima- tion of the seismic capacity curve for low-to-mid-rise shear type buildings.Furthermore,it is shown both the two-phase load pattern proposed and the invariant uniform pattern can be used for low-to-mid-rise shear-bending type and low-rise bending type of buildings.No suitable load patterns have been found for high-rise buildings. 展开更多
关键词 pushover analysis performance-based seismic design lateral load pattern nonlinear time history analysis
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Performance analysis and optimal design for well patterns in anisotropic formations 被引量:6
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作者 Liu Yuetian 《Petroleum Science》 SCIE CAS CSCD 2008年第3期251-257,共7页
The mechanism of the effects of anisotropic permeability on well patterns and reservoir development are investigated by coordinate transformation, fluid flow analysis, and reservoir development concepts. Anisotropy of... The mechanism of the effects of anisotropic permeability on well patterns and reservoir development are investigated by coordinate transformation, fluid flow analysis, and reservoir development concepts. Anisotropy of permeability has reconstructive effects on well patterns. The originally designed flooding units are broken up, and new pattern units are made up of the wells that belong to different original units. The behavior possesses strong randomness, and leads to a complicated relationship among the injection and production wells, and unpredictable productivity of the formations. To prevent the break-up of well patterns, well lines should be either parallel or perpendicular to the maximum principal direction of the anisotropic permeability (i.e. the fracture direction). To optimize the development effects ofanisotropic formations, the latitudinal and longitudinal well spacing of the well network are calculated from the principal values of the anisotropic permeability. 展开更多
关键词 Fractured reservoir anisotropic permeability performance analysis well pattern design
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Recent developments in multivariate pattern analysis for functional MRI 被引量:5
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作者 Zhi Yang Fang Fang Xuchu Weng 《Neuroscience Bulletin》 SCIE CAS CSCD 2012年第4期399-408,共10页
Multivariate pattern analysis(MVPA) is a recently-developed approach for functional magnetic resonance imaging(fMRI) data analyses.Compared with the traditional univariate methods,MVPA is more sensitive to subtle ... Multivariate pattern analysis(MVPA) is a recently-developed approach for functional magnetic resonance imaging(fMRI) data analyses.Compared with the traditional univariate methods,MVPA is more sensitive to subtle changes in multivariate patterns in fMRI data.In this review,we introduce several significant advances in MVPA applications and summarize various combinations of algorithms and parameters in different problem settings.The limitations of MVPA and some critical questions that need to be addressed in future research are also discussed. 展开更多
关键词 multivariate analysis FMRI pattern recognition computational biology
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Analysis of deformation and internal flow patterns for rising single bubbles in different liquids 被引量:4
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作者 Xin Li Pan Zhang +2 位作者 Jianlong Li Weiwen Wang Guanghui Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第4期745-758,共14页
Gas–liquid multiphase flow is a significant phenomenon in chemical processes. The rising behaviors of single bubbles in the quiescent liquids have been investigated but the internal flow patterns and deformation rule... Gas–liquid multiphase flow is a significant phenomenon in chemical processes. The rising behaviors of single bubbles in the quiescent liquids have been investigated but the internal flow patterns and deformation rules of bubbles, which influence the mass transfer efficiency to a large extent, have received much less attention. In this paper, the volume of fluid method was used to calculate the bubble shapes, pressure, velocity distributions,and the flow patterns inside the bubbles. The rising behavior of the bubbles with four different initial diameters,i.e., 3 mm, 5 mm, 7 mm and 9 mm was investigated in four various liquids including water, 61.23% glycerol,86.73% glycerol and 100% glycerol. The results show that the liquid properties and bubble initial diameters have great impacts on bubble shapes. Moreover, flow patterns inside the bubbles with different initial diameters were analyzed and classified into three types under the condition of different bubble shapes. Three correlations for predicting the maximum internal circulation inside the bubbles in 86.73% glycerol were presented and the R-square values were all bigger than 0.98. Through analyzing the pressure and velocity distributions around the bubbles, four rules of bubble deformation were also obtained to explain and predict the shapes. 展开更多
关键词 MULTIPHASE FLOW Bubble Interface DEFORMATION analysis INTERNAL FLOW pattern RISING behavior
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International patterns in incidence and mortality trends of pancreatic cancer in the last three decades: A joinpoint regression analysis 被引量:9
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作者 Irena Ilic Milena Ilic 《World Journal of Gastroenterology》 SCIE CAS 2022年第32期4697-4714,共18页
BACKGROUND Pancreatic cancer,as the one of most fatal malignancies,remains a critical issue in the global burden of disease.AIM To estimate trends in pancreatic cancer incidence and mortality worldwide in the last thr... BACKGROUND Pancreatic cancer,as the one of most fatal malignancies,remains a critical issue in the global burden of disease.AIM To estimate trends in pancreatic cancer incidence and mortality worldwide in the last three decades.METHODS A descriptive epidemiological study was done.Pancreatic cancer incidence and mortality data were obtained from the database of the World Health Organization.Analysis of pancreatic cancer incidence and mortality during 2020 was performed.The age-standardized rates(ASRs,expressed per 100000)were presented.To estimate trends of incidence and mortality of pancreatic cancer,joinpoint regression analysis was used:the average annual percent change(AAPC)with the corresponding 95%confidence interval(95%CI)was calculated.Additionally,analysis was performed by sex and age.In this paper,the trend analysis included only countries with high and medium data quality.RESULTS A total of 495773(262865 male and 232908 female)new cases and 466003(246840 male and 219163 female)deaths from pancreatic cancer were reported worldwide in 2020.In both sexes,most of the new cases(191348;38.6%of the total)and deaths(182074;39.1%of the total)occurred in the Western Pacific Region.In both sexes,the highest ASRs were found in the European Region,while the lowest rates were reported in the South-East Asia Region.The general pattern of rising pancreatic cancer incidence and mortality was seen across countries worldwide in observed period.Out of all countries with an increase in pancreatic cancer incidence,females in France and India showed the most marked rise in incidence rates(AAPC=+3.9%and AAPC=+3.7%,respectively).Decreasing incidence trends for pancreatic cancer were observed in some countries,but without significance.Out of all countries with an increase in pancreatic cancer mortality rates,Turkmenistan showed the most marked rise both in males(AAPC=+10.0%,95%CI:7.4–12.5)and females(AAPC=+6.4%,95%CI:3.5–9.5).The mortality trends of pancreatic cancer were decreasing in both sexes only in Canada and Mexico.CONCLUSION Further research is needed to explain the cause of large international differences in incidence and mortality trends of pancreatic cancer in last three decades. 展开更多
关键词 Pancreatic cancer INCIDENCE MORTALITY Joinpoint analysis International pattern
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Review of Remotely Sensed Imagery Classification Patterns Based on Object-oriented Image Analysis 被引量:9
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作者 LIU Yongxue LI Manchun +2 位作者 MAO Liang XU Feifei HUANG Shuo 《Chinese Geographical Science》 SCIE CSCD 2006年第3期282-288,共7页
With the wide use of high-resolution remotely sensed imagery, the object-oriented remotely sensed informa- tion classification pattern has been intensively studied. Starting with the definition of object-oriented remo... With the wide use of high-resolution remotely sensed imagery, the object-oriented remotely sensed informa- tion classification pattern has been intensively studied. Starting with the definition of object-oriented remotely sensed information classification pattern and a literature review of related research progress, this paper sums up 4 developing phases of object-oriented classification pattern during the past 20 years. Then, we discuss the three aspects of method- ology in detail, namely remotely sensed imagery segmentation, feature analysis and feature selection, and classification rule generation, through comparing them with remotely sensed information classification method based on per-pixel. At last, this paper presents several points that need to be paid attention to in the future studies on object-oriented RS in- formation classification pattern: 1) developing robust and highly effective image segmentation algorithm for multi-spectral RS imagery; 2) improving the feature-set including edge, spatial-adjacent and temporal characteristics; 3) discussing the classification rule generation classifier based on the decision tree; 4) presenting evaluation methods for classification result by object-oriented classification pattern. 展开更多
关键词 object-oriented image analysis remote sensing classification pattern
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An unsupervised pattern recognition methodology based on factor analysis and a genetic-DBSCAN algorithm to infer operational conditions from strain measurements in structural applications 被引量:7
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作者 Juan Carlos PERAFAN-LOPEZ Julian SIERRA-PEREZ 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2021年第2期165-181,共17页
Structural Health Monitoring(SHM) suggests the use of machine learning algorithms with the aim of understanding specific behaviors in a structural system. This work introduces a pattern recognition methodology for ope... Structural Health Monitoring(SHM) suggests the use of machine learning algorithms with the aim of understanding specific behaviors in a structural system. This work introduces a pattern recognition methodology for operational condition clustering in a structure sample using the well known Density Based Spatial Clustering of Applications with Noise(DBSCAN) algorithm.The methodology was validated using a data set from an experiment with 32 Fiber Bragg Gratings bonded to an aluminum beam placed in cantilever and submitted to cyclic bending loads under 13 different operational conditions(pitch angles). Further, the computational cost and precision of the machine learning pipeline called FA + GA-DBSCAN(which employs a combination of machine learning techniques including factor analysis for dimensionality reduction and a genetic algorithm for the automatic selection of initial parameters of DBSCAN) was measured. The obtained results have shown a good performance, detecting 12 of 13 operational conditions, with an overall precision over 90%. 展开更多
关键词 CLUSTERING DBSCAN Factor analysis FBGs pattern recognition Strain field
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Spatio-Temporal Variations in Co-Occurrence Patterns of Fish Communities in Haizhou Bay, China: Null Model Analysis 被引量:2
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作者 WANG Jiao ZHANG Chongliang +3 位作者 XUE Ying CHEN Yong REN Yiping XU Binduo 《Journal of Ocean University of China》 SCIE CAS CSCD 2019年第6期1497-1506,共10页
Co-occurrence pattern of fish species plays an important role in understanding the spatio-temporal structure and the stability of fish community.Species coexistence may vary with time and space.The co-occurrence patte... Co-occurrence pattern of fish species plays an important role in understanding the spatio-temporal structure and the stability of fish community.Species coexistence may vary with time and space.The co-occurrence patterns of fish species were examined using the C-score under fixed-fixed null model for fish communities in spring and autumn over different years in the Haizhou Bay,China.The results showed that fish assemblages in the whole bay had non-random patterns in spring and autumn over different years.However,the fish co-occurrence patterns were different for the northern and southern fish assemblages in spring and autumn.The northern fish assemblage showed structured pattern,whereas the southern assemblage were randomly assembled in spring.The co-occurrence patterns of fish communities were relatively stable over different years,and the number of significant species pairs in northern assemblage was more than that in the southern assemblage.Environmental heterogeneity played an important role in determining the distributions of fish species that formed significant species pairs,which might affect the co-occurrence patterns of northern and southern assemblages further in the Haizhou Bay. 展开更多
关键词 FISH COMMUNITY Haizhou BAY NULL model analysis SPECIES CO-OCCURRENCE pattern
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Spatial pattern analysis for quantification of landscape structure of Tadoba-Andhari Tiger Reserve,Central India 被引量:3
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作者 Ambica Paliwal Vinod Bihari 《Journal of Forestry Research》 SCIE CAS CSCD 2014年第1期185-192,共8页
Landscape structure is often regarded as an important factor that governs the distribution and abundance of species. Therefore it is critical to understand the landscapes and their dynamics. Patterns of landscape elem... Landscape structure is often regarded as an important factor that governs the distribution and abundance of species. Therefore it is critical to understand the landscapes and their dynamics. Patterns of landscape elements strongly influence the ecological characteristics. This study was designed to document and map the current status of the tropi-cal dry deciduous forest of the Tadoba-Andhari Tiger Reserve (TATR), Central India, (using IRS P6 LISS IV data) and to describe its landscape structure at three levels of organization viz. landscape, class, and patch. The study area was classified into 10 land cover classes that include 6 vegetation classes. The landscape structure was analyzed using FRAG-STATS using 12 set of indices. The TATR landscapes have a total of 2,307 patches with a mean patch size of 25.67 ha and patch density of 1.7 patches per km2. Amongst all land cover classes, mixed bamboo forest is dominant-it occupied maximum area (77.99%)-while riparian forest is least represented (0.32%). Mixed forest has maximum number of patches among all vegetation classes. Results have shown that despite being dominant in the area, mixed bamboo forest has low patch density (0.25/100 ha). Dominance of mixed bamboo forest is attributed to large patch sizes and not to the number of patches. This study has focussed on the approach of integrating satellite forest classification and forest inven-tory data for studying forest landscape patterns. 展开更多
关键词 Spatial pattern analysis landscape structure FRAGSTATS IRS P6 LISS IV.
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Population structure and spatial pattern analysis of Quercus aquifolioides on Sejila Mountain,Tibet,China 被引量:2
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作者 Zhiqiang Shen Jie Lu +4 位作者 Min Hua Xiaoqin Tang Xingle Qu Jingli Xue Jiangping Fang 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第2期400-409,共10页
Understanding population structure provides basic ecological data related to species and ecosystems.Our objective was to understand the mechanisms involved in the maintenance of Quercus aquifolioides populations.Using... Understanding population structure provides basic ecological data related to species and ecosystems.Our objective was to understand the mechanisms involved in the maintenance of Quercus aquifolioides populations.Using a 1 ha permanent sample plot data for Q.aquifolioides on Sejila Mountain,Tibet Autonomous Region(Tibet),China,we analyzed the population structure of Q.aquifolioides by combining data for diameter class,static life table and survival curve.Simultaneously,the spatial distribution of Q.aquifolioides was studied using Ripley’s L Function in point pattern analysis.The results showed:(1) Individuals in Q.aquifolioides populations were mainly aggregated in the youngest age classes,that accounted for94.3% of the individuals; the older age classes had much smaller populations.Although the youngest age classes(ClassesⅠ and Ⅱ) had fewer individuals than Class Ⅲ,the total number of individuals in classes Ⅰ and Ⅱ was also greater than in classes Ⅳ to Ⅸ.In terms of tree height,fewsaplings,more medium-sized saplings and few large-sized trees were found.The diameter class structure of Q.aquifolioides populations formed an atypical ‘pyramid’type; the population was expanding,but growth was limited,tending toward a stable population.(2) Mortality of Q.aquifolioides increased continuously with age; life expectancy decreased over time,and the survivorship curve was close to a Deevey I curve.(3) The spatial distribution pattern of Q.aquifolioides varied widely across different developmental stages.Saplings and medium-sized tree showed aggregated distributions at the scales of 0–33 m and 0–29 m,respectively.The aggregation intensities of saplings and medium-sized trees at small scales were significantly stronger than that of large-sized trees.However,large-sized trees showed a random distribution at most scales.(4) No correlation was observed among saplings,medium-and large-sized trees at small scales,while a significant and negative association was observed as the scale increased.Strong competition was found among saplings,medium-and large-sized trees,while no significant association was observed between medium-and largesized trees at all scales.Biotic interactions and local ecological characteristics influenced the spatial distribution pattern of Q.aquifolioides populations most strongly. 展开更多
关键词 Point pattern analysis Population structure Quercus aquifolioides Sejila Mountain Spatial distribution pattern
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