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The reflection of hierarchical cluster analysis of co-occurrence matrices in SPSS 被引量:5
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作者 Qiuju ZHOU Fuhai LENG Loet LEYDESDORFF 《Chinese Journal of Library and Information Science》 2015年第2期11-24,共14页
Purpose: To discuss the problems arising from hierarchical cluster analysis of co-occurrence matrices in SPSS, and the corresponding solutions. Design/methodology/approach: We design different methods of using the S... Purpose: To discuss the problems arising from hierarchical cluster analysis of co-occurrence matrices in SPSS, and the corresponding solutions. Design/methodology/approach: We design different methods of using the SPSS hierarchical clustering module for co-occurrence matrices in order to compare these methods. We offer the correct syntax to deactivate the similarity algorithm for clustering analysis within the hierarchical clustering module of SPSS. Findings: When one inputs co-occurrence matrices into the data editor of the SPSS hierarchical clustering module without deactivating the embedded similarity algorithm, the program calculates similarity twice, and thus distorts and overestimates the degree of similarity. Practical implications: We offer the correct syntax to block the similarity algorithm for clustering analysis in the SPSS hierarchical clustering module in the case of co-occurrence matrices. This syntax enables researchers to avoid obtaining incorrect results. Originality/value: This paper presents a method of editing syntax to prevent the default use of a similarity algorithm for SPSS's hierarchical clustering module. This will help researchers, especially those from China, to properly implement the co-occurrence matrix when using SPSS for hierarchical cluster analysis, in order to provide more scientific and rational results. 展开更多
关键词 Co-occurrence matrices hierarchical cluster analysis SPSS Similarity algorithm The syntax editor
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Compatibility Rules of Neonatal Parenteral Nutrition Prescriptions Based on Association Rules and Hierarchical Cluster Analysis
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作者 Xinhong ZHAO Chao SUN +3 位作者 Yanwu ZHAO Ying JIN Ying WANG Zhenhua LIU 《Medicinal Plant》 CAS 2022年第1期39-43,51,共6页
[Objectives]To explore the compatibility rules of neonatal parenteral nutrition(PN)prescriptions based on association rules and hierarchical cluster analysis,thereby providing a reference for standardizing neonatal pa... [Objectives]To explore the compatibility rules of neonatal parenteral nutrition(PN)prescriptions based on association rules and hierarchical cluster analysis,thereby providing a reference for standardizing neonatal parenteral nutrition supportive therapy.[Methods]The data about neonatal PN formulations prepared by the Pharmacy Intravenous Admixture Services(PIVAS)of the Affiliated Hospital of Chengde Medical University from July 2015 to June 2021 were collected.The general information of the prescriptions and the frequency of drug use were analyzed with Excel 2019;the boxplot of drug dosing was drawn using GraphPad 8.0 software;and SPSS Modeler 18.0 and SPSS Statistics 26.0 were used to perform association rules and hierarchical cluster analysis.[Results]A total of 11488 PN prescriptions were collected from 1421 newborns,involving 18 kinds of drugs,which were divided into 11 types of nutrients.Association rules analysis yielded 84 nutrient substance combinations.The combination of fat emulsion-water-soluble vitamins-fat-soluble vitamins-glucose-amino acids had the highest confidence(99.95%).The hierarchical cluster analysis divided nutrients into 5 types.[Conclusions]The prescriptions of PN for newborns were composed of five types of nutrients:amino acids,fat emulsion,glucose,water-soluble vitamins,and fat-soluble vitamins.According to the lack of electrolytes and trace elements,appropriate drugs can be chosen to meet nutritional demands.This study provides reference basis for reasonable selection of drugs for neonatal PN prescriptions and further standardization of PN supportive therapy in newborns. 展开更多
关键词 Neonatal parenteral nutrition prescription Pharmacy Intravenous Admixture Services Association rules hierarchical cluster analysis
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COVID19 Outbreak:A Hierarchical Framework for User Sentiment Analysis
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作者 Ahmed F.Ibrahim M.Hassaballah +2 位作者 Abdelmgeid A.Ali Yunyoung Nam Ibrahim A.Ibrahim 《Computers, Materials & Continua》 SCIE EI 2022年第2期2507-2524,共18页
Social networking sites in the most modernized world are flooded with large data volumes.Extracting the sentiment polarity of important aspects is necessary;as it helps to determine people’s opinions through what the... Social networking sites in the most modernized world are flooded with large data volumes.Extracting the sentiment polarity of important aspects is necessary;as it helps to determine people’s opinions through what they write.The Coronavirus pandemic has invaded the world and been given a mention in the social media on a large scale.In a very short period of time,tweets indicate unpredicted increase of coronavirus.They reflect people’s opinions and thoughts with regard to coronavirus and its impact on society.The research community has been interested in discovering the hidden relationships from short texts such as Twitter and Weiboa;due to their shortness and sparsity.In this paper,a hierarchical twitter sentiment model(HTSM)is proposed to show people’s opinions in short texts.The proposed HTSM has two main features as follows:constructing a hierarchical tree of important aspects from short texts without a predefined hierarchy depth and width,as well as analyzing the extracted opinions to discover the sentiment polarity on those important aspects by applying a valence aware dictionary for sentiment reasoner(VADER)sentiment analysis.The tweets for each extracted important aspect can be categorized as follows:strongly positive,positive,neutral,strongly negative,or negative.The quality of the proposed model is validated by applying it to a popular product and a widespread topic.The results show that the proposed model outperforms the state-of-the-art methods used in analyzing people’s opinions in short text effectively. 展开更多
关键词 COVID19 COVID data sentiment analysis hierarchical clustering sentiment tree
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Determination of bioactive components in the fruits of Cercis chinensis Bunge by HPLC-MS/MS and quality evaluation by principal components and hierarchical cluster analyses 被引量:4
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作者 Yuan Hong Xiaoyan Liao Zilin Chen 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2021年第4期465-471,共7页
The fruits of leguminous plants Cercis Chinensis Bunge are still overlooked although they have been reported to be antioxidative because of the limited information on the phytochemicals of C.chinensis fruits.A simple,... The fruits of leguminous plants Cercis Chinensis Bunge are still overlooked although they have been reported to be antioxidative because of the limited information on the phytochemicals of C.chinensis fruits.A simple,rapid and sensitive HPLC-MS/MS method was developed for the identification and quantitation of the major bioactive components in C.chinensis fruits.Eighteen polyphenols were identified,which are first reported in C.chinensis fruits.Moreover,ten components were simultaneously quantified.The validated quantitative method was proved to be sensitive,reproducible and accurate.Then,it was applied to analyze batches of C.chinensis fruits from different phytomorph and areas.The principal components analysis(PCA)realized visualization and reduction of data set dimension while the hierarchical cluster analysis(HCA)indicated that the content of phenolic acids or all ten components might be used to differentiate C.chinensis fruits of different phytomorph. 展开更多
关键词 C.chinensis fruits HPLC-MS/MS POLYPHENOLS Principal components analysis hierarchical cluster analysis
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Mathematical Tools of Cluster Analysis 被引量:9
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作者 Peter Trebuna Jana Halcinova 《Applied Mathematics》 2013年第5期814-816,共3页
The paper deals with cluster analysis and comparison of clustering methods. Cluster analysis belongs to multivariate statistical methods. Cluster analysis is defined as general logical technique, procedure, which allo... The paper deals with cluster analysis and comparison of clustering methods. Cluster analysis belongs to multivariate statistical methods. Cluster analysis is defined as general logical technique, procedure, which allows clustering variable objects into groups-clusters on the basis of similarity or dissimilarity. Cluster analysis involves computational procedures, of which purpose is to reduce a set of data on several relatively homogenous groups-clusters, while the condition of reduction is maximal and simultaneously minimal similarity of clusters. Similarity of objects is studied by the degree of similarity (correlation coefficient and association coefficient) or the degree of dissimilarity-degree of distance (distance coefficient). Methods of cluster analysis are on the basis of clustering classified as hierarchical or non-hierarchical methods. 展开更多
关键词 cluster analysis hierarchical cluster analysis Methods Non-hierarchical cluster analysis Methods
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A New Approach to Investigate Students’ Behavior by Using Cluster Analysis as an Unsupervised Methodology in the Field of Education
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作者 Onofrio Rosario Battaglia Benedetto Di Paola Claudio Fazio 《Applied Mathematics》 2016年第15期1649-1673,共25页
The problem of taking a set of data and separating it into subgroups where the elements of each subgroup are more similar to each other than they are to elements not in the subgroup has been extensively studied throug... The problem of taking a set of data and separating it into subgroups where the elements of each subgroup are more similar to each other than they are to elements not in the subgroup has been extensively studied through the statistical method of cluster analysis. In this paper we want to discuss the application of this method to the field of education: particularly, we want to present the use of cluster analysis to separate students into groups that can be recognized and characterized by common traits in their answers to a questionnaire, without any prior knowledge of what form those groups would take (unsupervised classification). We start from a detailed study of the data processing needed by cluster analysis. Then two methods commonly used in cluster analysis are before described only from a theoretical point a view and after in the Section 4 through an example of application to data coming from an open-ended questionnaire administered to a sample of university students. In particular we describe and criticize the variables and parameters used to show the results of the cluster analysis methods. 展开更多
关键词 EDUCATION Unsupervised Methods hierarchical clustering Not-hierarchical clustering Quantitative analysis
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Cluster Analysis Assisted Float-Encoded Genetic Algorithm for a More Automated Characterization of Hydrocarbon Reservoirs
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作者 Norbert Péter Szabó Mihály Dobróka Réka Kavanda 《Intelligent Control and Automation》 2013年第4期362-370,共9页
A genetic algorithm-based joint inversion method is presented for evaluating hydrocarbon-bearing geological formations. Conventional inversion procedures routinely used in the oil industry perform the inversion proces... A genetic algorithm-based joint inversion method is presented for evaluating hydrocarbon-bearing geological formations. Conventional inversion procedures routinely used in the oil industry perform the inversion processing of borehole geophysical data locally. As having barely more types of data than unknowns in a depth, a set of marginally over-determined inverse problems has to be solved along a borehole, which is a rather noise sensitive procedure. For the reduction of noise effect, the amount of overdetermination must be increased. To fulfill this requirement, we suggest the use of our interval inversion method, which inverts simultaneously all data from a greater depth interval to estimate petrophysical parameters of reservoirs to the same interval. A series expansion based discretization scheme ensures much more data against unknowns that significantly reduces the estimation error of model parameters. The knowledge of reservoir boundaries is also required for reserve calculation. Well logs contain information about layer-thicknesses, but they cannot be extracted by the local inversion approach. We showed earlier that the depth coordinates of layerboundaries can be determined within the interval inversion procedure. The weakness of method is that the output of inversion is highly influenced by arbitrary assumptions made for layer-thicknesses when creating a starting model (i.e. number of layers, search domain of thicknesses). In this study, we apply an automated procedure for the determination of rock interfaces. We perform multidimensional hierarchical cluster analysis on well-logging data before inversion that separates the measuring points of different layers on a lithological basis. As a result, the vertical distribution of clusters furnishes the coordinates of layer-boundaries, which are then used as initial model parameters for the interval inversion procedure. The improved inversion method gives a fast, automatic and objective estimation to layer-boundaries and petrophysical parameters, which is demonstrated by a hydrocarbon field example. 展开更多
关键词 hierarchical cluster analysis GENETIC Algorithm Well-Logging INTERVAL INVERSION
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The application of fuzzy equivalence relation based on the quotient space in cluster analysis
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作者 SHEN Qin-wei ZHANG Yuan 《International Journal of Technology Management》 2014年第8期58-61,共4页
关键词 模糊等价关系 模糊聚类分析 商空间 等价关系矩阵 应用 基础 分层结构 矩阵转换
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Derringer desirability and kinetic plot LC-column comparison approach for MS-compatible lipopeptide analysis 被引量:1
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作者 Matthias D’Hondt Frederick Verbeke +3 位作者 Sofie Stalmans Bert Gevaert Evelien Wynendaele Bart De Spiegeleer 《Journal of Pharmaceutical Analysis》 SCIE CAS 2014年第3期173-182,共10页
Lipopeptides are currently re-emerging as an interesting subgroup in the peptide research field, having historical applications as antibacterial and antifungal agents and new potential applications as antiviral, antit... Lipopeptides are currently re-emerging as an interesting subgroup in the peptide research field, having historical applications as antibacterial and antifungal agents and new potential applications as antiviral, antitumor, immune-modulating and cell-penetrating compounds. However, due to their specific structure, chromatographic analysis often requires special buffer systems or the use of trifluoroacetic acid, limiting mass spectrometry detection. Therefore, we used a traditional aqueous/acetonitrile based gradient system, containing 0.1% (m/v) formic acid, to separate four pharmaceutically relevant lipopeptides (polymyxin B1, caspofungin, daptomycin and gramicidin A1), which were selected based upon hierarchical cluster analysis (HCA) and principal component analysis (PCA).In total, the performance of four different C18 columns, including one UPLC column, were evaluated using two parallel approaches. First, a Derringer desirability function was used, whereby six single and multiple chromatographic response values were rescaled into one overall D-value per column. Using this approach, the YMC Pack Pro C18 column was ranked as the best column for general MS-compatible lipopeptide separation. Secondly, the kinetic plot approach was used to compare the different columns at different flow rate ranges. As the optimal kinetic column performance is obtained at its maximal pressure, the length elongation factor λ(Pmax/Pexp) was used to transform the obtained experimental data (retention times and peak capacities) and construct kinetic performance limit (KPL) curves, allowing a direct visual and unbiased comparison of the selected columns, whereby the YMC Triart C18 UPLC and ACE C18 columns performed as best. Finally, differences in column performance and the (dis)advantages of both approaches are discussed. 展开更多
关键词 LIPOPEPTIDE hierarchical cluster analysis (hca Principal component analysis (PCA) LC-MS Kinetic plot Derringer desirability function
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Multivariate analysis of fluorescence and source identification of dissolved organic matter in Jiaozhou Bay, China 被引量:2
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作者 JIANG Fenghua YANG Baijuan +2 位作者 LEE Frank Sen-Chun WANG Xiaoru CAO Xuail 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2009年第2期60-72,共13页
Hierarchical clustering analysis and principal component analysis (PCA) methods were used to assess the similarities and dissimilarities of the entire Excitation-emission matrix spectroscopy (EEMs) data sets of sa... Hierarchical clustering analysis and principal component analysis (PCA) methods were used to assess the similarities and dissimilarities of the entire Excitation-emission matrix spectroscopy (EEMs) data sets of samples collected from Jiaozhou Bay, China. The results demonstrate that multivariate analysis facilitates the complex data treatment and spectral sorting processes, and also enhances the probability to reveal otherwise hidden information concerning the chemical characteristics of the dissolved organic matter (DOM). The distribution of different water samples as revealed by multivariate results has been used to track the movement of DOM material in the study area, and the interpretation is supported by the results obtained from the numerical simulation model of substance tracing technique, which show that the substance discharged by Haibo River can be distributed in Jiaozhou Bay. 展开更多
关键词 dissolved organic matter (DOM) excitation-emission matrix spectroscopy (EEMs) hierarchical cluster analysis principal component analysis (PCA) Jiaozhou Bay
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Water Quality Assessment in the Bamoun Plateau, Western-Cameroon: Hydrogeochemical Modelling and Multivariate Statistical Analysis Approach 被引量:1
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作者 Zakari Mfonka Amidou Kpoumié +7 位作者 Abdou Nasser Ngouh Oumar Farouk Mouncherou Daouda Nsangou Felaniaina Rakotondrabe Alain Fouépé Takounjou Mounira Zammouri Jules Rémy Ndam Ngoupayou Paul-Désiré Ndjigui 《Journal of Water Resource and Protection》 2021年第2期112-138,共27页
This study focuses on the geochemical and bacteriological investigation of surface and ground water in the Bamoun plateau (Western-Cameroon). During the period from September 2013 to August 2014, 71 samples were colle... This study focuses on the geochemical and bacteriological investigation of surface and ground water in the Bamoun plateau (Western-Cameroon). During the period from September 2013 to August 2014, 71 samples were collected from two springs, one borehole, four wells and the Nchi stream for analysis of major elements. In order to obtain the characteristics of the various species of bacteria, 7 samples were selected. The analytical method adopted for this study is the conventional hydrochemical technic and multivariate statistical analysis, coupled with the hydrogeochemical modelling. The results revealed that, water from the zone under study are acidic to basic, very weakly to weakly mineralized. Four types of water were identified: 1) CaMg-HCO<sub>3</sub>;2) CaMg-Cl-SO<sub>4</sub>;3) NaCl-SO<sub>4</sub> and 4) NaK-HCO<sub>3</sub>. The major elements were all listed in the World Health Organization guidelines for drinking water quality, except for nitrates which was found at a concentration > 50 mg /l <span style="white-space:nowrap;">NO<sup>-</sup><sub style="margin-left:-7px;">3</sub> </span>in the borehole F401. As for the hydrobiological aspect, the entire sample contained all the bacteriological species except for spring S301 and well P401. According to the hydrogeochemical modelling, the Gibbs model and multivariate statistical tests, the quality of surface and ground water of the Foumban locality is influenced by two important factors: 1) the natural factors characterized by the water-rock interaction, evapotranspiration/crystallization, 2) the anthropogenic factors such as: uncontrolled discharges of liquid and solid effluents of all kinds and without any prior treatment within the ground and the strong urbanization accompanied by lack of sanitation and insufficient care. 展开更多
关键词 Foumban Surface and Ground Water Water-Rock Interaction Bacteriological Parameters hierarchical clustering analysis Principal Component analysis
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Analyzing the Urban Hierarchical Structure Based on Multiple Indicators of Economy and Industry: An Econometric Study in China 被引量:1
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作者 Jing Cheng Yang Xie Jie Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第6期1831-1855,共25页
For a city,analyzing its advantages,disadvantages and the level of economic development in a country is important,especially for the cities in China developing at flying speed.The corresponding literatures for the cit... For a city,analyzing its advantages,disadvantages and the level of economic development in a country is important,especially for the cities in China developing at flying speed.The corresponding literatures for the cities in China have not considered the indicators of economy and industry in detail.In this paper,based on multiple indicators of economy and industry,the urban hierarchical structure of 285 cities above the prefecture level in China is investigated.The indicators from the economy,industry,infrastructure,medical care,population,education,culture,and employment levels are selected to establish a new indicator system for analyzing urban hierarchical structure.The factor analysis method is used to investigate the relationship between the variables of selected indicators and obtain the score of each common factor and comprehensive scores and rankings for 285 cities above the prefecture level in China.According to the comprehensive scores,285 cities above the prefecture level are clustered into 15 levels by using K-means clustering algorithm.Then,the hierarchical structure system of the cities above the prefecture level in China is obtained and corresponding policy implications are proposed.The results and implications can not only be applied to the urban planning and development in China but also offer a reference on other developing countries.The methodologies used in this paper can also be applied to study the urban hierarchical structure in other countries. 展开更多
关键词 Urban planning hierarchical structure prefecture-level city factor analysis method K-means clustering algorithm China
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Air Traffic Operation Complexity Analysis Based on Metrics System
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作者 Xie Hua Cong Wei +1 位作者 Hu Ming hua Liu Sifeng 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2016年第4期461-468,共8页
In order to quantitatively analyze air traffic operation complexity,multidimensional metrics were selected based on the operational characteristics of traffic flow.The kernel principal component analysis method was ut... In order to quantitatively analyze air traffic operation complexity,multidimensional metrics were selected based on the operational characteristics of traffic flow.The kernel principal component analysis method was utilized to reduce the dimensionality of metrics,therefore to extract crucial information in the metrics.The hierarchical clustering method was used to analyze the complexity of different airspace.Fourteen sectors of Guangzhou Area Control Center were taken as samples.The operation complexity of traffic situation in each sector was calculated based on real flight radar data.Clustering analysis verified the feasibility and rationality of the method,and provided a reference for airspace operation and management. 展开更多
关键词 operation complexity traffic metrics kernel primary component analysis hierarchical clustering
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Description and Classification of Leather Defects Based on Principal Component Analysis
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作者 丁彩红 黄浩 杨延竹 《Journal of Donghua University(English Edition)》 EI CAS 2018年第6期473-479,共7页
The accurate extraction and classification of leather defects is an important guarantee for the automation and quality evaluation of leather industry. Aiming at the problem of data classification of leather defects,a ... The accurate extraction and classification of leather defects is an important guarantee for the automation and quality evaluation of leather industry. Aiming at the problem of data classification of leather defects,a hierarchical classification for defects is proposed.Firstly,samples are collected according to the method of minimum rectangle,and defects are extracted by image processing method.According to the geometric features of representation, they are divided into dot,line and surface for rough classification. From analysing the data which extracting the defects of geometry,gray and texture,the dominating characteristics can be acquired. Each type of defect by choosing different and representative characteristics,reducing the dimension of the data,and through these characteristics of clustering to achieve convergence effectively,realize extracted accurately,and digitized the defect characteristics,eventually establish the database. The results showthat this method can achieve more than 90% accuracy and greatly improve the accuracy of classification. 展开更多
关键词 DEFECT detection hierarchical classification principal component analysis REDUCE DIMENSION clustering model
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基于PCA-HCA模型的我国节水分区
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作者 邓晰元 郑锦涛 +4 位作者 周晓辉 马涛 郑皓 梁秀 王国庆 《南水北调与水利科技(中英文)》 CAS CSCD 北大核心 2023年第1期137-147,共11页
为因地制宜地推进我国节水工作,以我国31个省(自治区、直辖市)为基础单元,按照领域协同、统筹兼顾、区划完整、有效衔接的原则,从水资源状况、社会经济条件、农业用水特征、工业用水特征和生活用水特征5个方面选取14项指标,构建节水分... 为因地制宜地推进我国节水工作,以我国31个省(自治区、直辖市)为基础单元,按照领域协同、统筹兼顾、区划完整、有效衔接的原则,从水资源状况、社会经济条件、农业用水特征、工业用水特征和生活用水特征5个方面选取14项指标,构建节水分区指标体系。采用主成分分析(principal component analysis,PCA)和系统聚类分析(hierarchical clustering analysis,HCA)相结合的方法,将31个省(自治区、直辖市)划分成为东北地区、华北地区、西北地区、东南沿海地区、华中地区和西南地区6大节水分区。节水分区特征分析结果表明,各分区间水资源、经济社会和分领域用水指标差异显著,水资源短缺和经济社会发展对节约用水具有显著促进作用。 展开更多
关键词 节水分区 主成分分析 系统聚类分析 指标体系 特征分析
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A Multi-Agent School Simulation Based on Hierarchical Social Networks
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作者 Yu Zhang Jiang Wu Lizhu Ma 《Intelligent Information Management》 2014年第4期196-210,共15页
The quality of K-12 education has been a very big concern for years. Previous methods studied only one or two factors, such as school choice, or teacher quality, on school performance. Therefore the results they provi... The quality of K-12 education has been a very big concern for years. Previous methods studied only one or two factors, such as school choice, or teacher quality, on school performance. Therefore the results they provide can be limited. We propose a multi-agent approach to integrate multiple actors in a school system. These actors include teachers, students, supporting staffs and administrators. The interactions among these actors compose a hierarchical school social network. We first detect the hierarchical community structure in this school network by using an agglomerative hierarchical algorithm. Existing agglomerative hierarchical algorithms usually calculate similarity or dissimilarity between two clusters by using some measure of distance between pairs of observations. We, however, develop a method that calculates similarity based on social interactions between interactions is essential in multi-agent systems. Our algorithm is applied to 15 school districts in Bexar County, Texas, and it provides satisfying results on generating the hierarchical structure of all school districts. We then use the detected structure of the social network to evaluate the school system’s organization performance. We design and implement a funding evaluation model to decompose the funding policy task into subtasks and then evaluate these subtasks by using funding distribution policies from past years and looking for possible relationships between student performances and funding policies. Experiments in the 15 school districts in Bexar County show no significant correlation between student performance and the amount of the funding a school district received. 展开更多
关键词 hierarchical clusterING K-12 Education MULTI-AGENT Systems SOCIAL Network analysis
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谢宾斯基分形结构声散射特性与视觉偏好评价
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作者 徐洪澎 谭令舸 +1 位作者 吴健梅 康健 《应用声学》 CSCD 北大核心 2024年第2期321-329,共9页
声扩散界面设计应兼顾声学和美学需求。结合参数化设计方法,谢宾斯基分形的模块化结构具有灵活生成个性化界面的潜力。然而,针对分形结构声学特性与视觉效益尚缺乏综合的量化研究。根据谢宾斯基分形的构造规则提出了一种宽频的扩散结构... 声扩散界面设计应兼顾声学和美学需求。结合参数化设计方法,谢宾斯基分形的模块化结构具有灵活生成个性化界面的潜力。然而,针对分形结构声学特性与视觉效益尚缺乏综合的量化研究。根据谢宾斯基分形的构造规则提出了一种宽频的扩散结构设计方法,分别从声学性能与视觉偏好的角度,研究模块形状、模块高度和随机排布程度对性能的影响。采用边界元素法的数值仿真与实测验证,结合虚拟仿真技术的主观调查,以及多目标综合分析,探究分形设计要素的作用机制和最佳阈值范围。结果表明,与相同体量的传统二次残差扩散体相比,具有不同平面尺寸和高度模块的分形结构改善了扩散性能,特别是在1 kHz以下的中低频范围。此外,发现在室内使用中高复杂度(迭代3次)、低随机排布、谢宾斯基三角截锥分形结构,有助于提高居住者对环境的偏好度。 展开更多
关键词 谢宾斯基分形 声扩散体 扩散系数 视觉偏好 层次分析
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基于土地利用结构的河流岸带生态系统服务簇识别
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作者 徐慧 高雨慧 +3 位作者 周强 闫怀春 蔡晨茵 刘志杰 《水生态学杂志》 CSCD 北大核心 2024年第3期52-59,共8页
为识别河流岸带土地利用与生态服务价值的空间结构,从河流岸带保护角度选取水资源保护、净化环境、水文调节、土壤保持、维持养分循环、生物多样性6项生态服务功能,基于遥感影像解译的土地利用数据,运用修正的当量因子法估算得到生态服... 为识别河流岸带土地利用与生态服务价值的空间结构,从河流岸带保护角度选取水资源保护、净化环境、水文调节、土壤保持、维持养分循环、生物多样性6项生态服务功能,基于遥感影像解译的土地利用数据,运用修正的当量因子法估算得到生态服务价值的空间分布规律,进而进行层次聚类分析识别河流岸带生态服务簇,并应用于太湖流域湖西区溧阳市县级河流——竹箦河作为实例研究。结果表明:(1)竹箦河河岸带6项生态服务价值呈现出显著的空间异质性和聚集性;(2)竹箦河河岸带可划分为5大类生态服务簇,分别为水源涵养型、绿色多元型、经济生态型、生态脆弱型以及耗水污染型;(3)各类服务簇的生态系统服务特点与空间布局分异明显,与岸带实际土地利用结构相协调,揭示了竹箦河河岸带生态服务功能普遍较薄弱的现状。研究结果可为竹箦河及类似平原地区骨干河流岸带功能区划分以及河岸带生态保护与修复方案的制定提供理论参考。 展开更多
关键词 河岸带 土地利用结构 生态系统服务簇 层次聚类分析
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Analysis of genetic diversity in banana cultivars(Musa cvs.) from the South of Oman using AFLP markers and classification by phylogenetic,hierarchical clustering and principal component analyses 被引量:2
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作者 Umezuruike Linus OPARA Dan JACOBSON Nadiya Abubakar AL-SAADY 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2010年第5期332-341,共10页
Banana is an important crop grown in Oman and there is a dearth of information on its genetic diversity to assist in crop breeding and improvement programs.This study employed amplified fragment length polymorphism(AF... Banana is an important crop grown in Oman and there is a dearth of information on its genetic diversity to assist in crop breeding and improvement programs.This study employed amplified fragment length polymorphism(AFLP) to investigate the genetic variation in local banana cultivars from the southern region of Oman.Using 12 primer combinations,a total of 1094 bands were scored,of which 1012 were polymorphic.Eighty-two unique markers were identified,which revealed the distinct separation of the seven cultivars.The results obtained show that AFLP can be used to differentiate the banana cultivars.Further classification by phylogenetic,hierarchical clustering and principal component analyses showed significant differences between the clusters found with molecular markers and those clusters created by previous studies using morphological analysis.Based on the analytical results,a consensus dendrogram of the banana cultivars is presented. 展开更多
关键词 MUSA Genetic diversity Amplified fragment length polymorphism(AFLP) PHYLOGENETICS Principal component analysis(PCA) hierarchical clustering analysis(hca) Oman
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UPLC-MS/MS法同时测定透骨香中6种成分的含量
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作者 金林 周祖英 +4 位作者 周家华 迟明艳 郑林 黄勇 黄闻 《中成药》 CAS CSCD 北大核心 2024年第1期22-28,共7页
目的建立UPLC-MS/MS法同时测定透骨香中原儿茶酸、表儿茶素、绿原酸、槲皮苷、白珠树苷、滇白珠苷A的含量。方法分析采用Waters BEH C_(18)色谱柱(2.1 mm×100 mm,1.7μm);流动相水(含0.1%甲酸)-乙腈(含0.1%甲酸),梯度洗脱;体积流量... 目的建立UPLC-MS/MS法同时测定透骨香中原儿茶酸、表儿茶素、绿原酸、槲皮苷、白珠树苷、滇白珠苷A的含量。方法分析采用Waters BEH C_(18)色谱柱(2.1 mm×100 mm,1.7μm);流动相水(含0.1%甲酸)-乙腈(含0.1%甲酸),梯度洗脱;体积流量0.3 mL/min;柱温40℃;电喷雾离子源;正负离子扫描;多反应监测模式。采用层次聚类分析(HCA)、主成分分析(PCA)筛选影响药材质量的重要成分。结果6种成分在各自范围内线性关系良好(r≥0.9982),平均加样回收率98.76%~101.88%,RSD 1.0%~2.5%。透骨香根、地上部分所含成分有较大差异,白珠树苷、表儿茶素、原儿茶酸是质量标志成分。结论该方法准确、高效,可用于透骨香的质量控制。 展开更多
关键词 透骨香 化学成分 含量测定 UPLC-MS/MS 层次聚类分析(hca) 主成分分析(PCA)
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