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International Renowned Databases and Institutions Indexing Asian Agricultural Research
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《Asian Agricultural Research》 2025年第12期52-52,共1页
Asian Agricultural Research(ISSN1943-9903),founded in 2009,is a monthly comprehensive agricultural academic journal published and approved by the Library of Congress of the United States of America.
关键词 Library Congress indexING international renowned databases monthly publication agricultural academic journal Asian agricultural research United States America
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Cache-Conscious Index Mechanism for Main-Memory Databases 被引量:5
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作者 SUN Li-mei SONG Bao-yan YU Ya-xin LI Fang-fang YU Ge 《Wuhan University Journal of Natural Sciences》 EI CAS 2006年第1期309-312,共4页
Recent studies have addressed that the cache be havior is important in the design of main memory index structures. Cache-conscious indices such as the CSB^+-tree are shown to outperform conventional main memory indic... Recent studies have addressed that the cache be havior is important in the design of main memory index structures. Cache-conscious indices such as the CSB^+-tree are shown to outperform conventional main memory indices such as the AVL-tree and the T-tree. This paper proposes a cacheconscious version of the T-tree, CST-tree, defined according to the cache-conscious definition. To separate the keys within a node into two parts, the CST-tree can gain higher cache hit ratio. 展开更多
关键词 index structure main memory database real time application cache-conscious T-tree indexing CST-tree indexing
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Spatial-temporal Analysis of Daily Air Quality Index in the Yangtze River Delta Region of China During 2014 and 2016 被引量:10
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作者 YE Lei OU Xiangjun 《Chinese Geographical Science》 SCIE CSCD 2019年第3期382-393,共12页
Urban air pollution is a prominent problem related to the urban development in China, especially in the densely populated urban agglomerations. Therefore, scientific examination of regional variation of air quality an... Urban air pollution is a prominent problem related to the urban development in China, especially in the densely populated urban agglomerations. Therefore, scientific examination of regional variation of air quality and its dominant factors is of great importance to regional environmental management. In contrast to traditional air pollution researches which only concentrate on a single year or a single pollutant, this paper analyses spatiotemporal patterns and determinants of air quality in disparate regions based on the air quality index(AQI) of the Yangtze River Delta region(YRD) of China from 2014 to 2016. Results show that the annual average value of the AQI in the YRD region decreases from 2014 to 2016 and exhibit a basic characteristic of ‘higher in winter, lower in summer and slightly high in spring and autumn'. The attainment rate of the AQI shows an apparently spatial stratified heterogeneity, Hefei metropolitan area and Nanjing metropolitan area keeping the worst air quality. The frequency of air pollution occurring in large regions was gradually decreasing during the study period. Drawing from entropy method analysis, industrialization and urbanization represented by per capita GDP and total energy consumption were the most important factors. Furthermore, population agglomeration is a factor that cannot be ignored especially in some mega-cities. Limited to data collection, more research is needed to gain insight into the spatiotemporal pattern and influence mechanism in the future. 展开更多
关键词 air quality index(AQI) spatial-temporal evolution contributing FACTORS YANGTZE RIVER Delta(YRD)
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Chinese Keyword Search by Indexing in Relational Databases
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作者 Liang Zhu Lijuan Pan Qin Ma 《Journal of Software Engineering and Applications》 2012年第12期107-112,共6页
In this paper, we propose a new method based on index to realize IR-style Chinese keyword search with ranking strategies in relational databases. This method creates an index by using the related information of tuple ... In this paper, we propose a new method based on index to realize IR-style Chinese keyword search with ranking strategies in relational databases. This method creates an index by using the related information of tuple words and presents a ranking strategy in terms of the nature of Chinese words. For a Chinese keyword query, the index is used to match query search words and the tuple words in index quickly, and to compute similarities between the query and tuples by the ranking strategy, and then the set of identifiers of candidate tuples is generated. Thus, we retrieve top-N results of the query using SQL selection statements and output the ranked answers according to the similarities. The experimental results show that our method is efficient and effective. 展开更多
关键词 RELATIONAL database CHINESE KEYWORD Search index RANKING Strategy
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Toward Exhaustive Teaching of Relational Database Indexes
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作者 Massimo Macera Paolo Rocchil 《Computer Technology and Application》 2012年第8期578-583,共6页
There are several indexing techniques that can optimize system performances. The choice of the right index type in a schema can improve the DB performances by up to 80%. Unfortunately the illustrations of the various ... There are several indexing techniques that can optimize system performances. The choice of the right index type in a schema can improve the DB performances by up to 80%. Unfortunately the illustrations of the various techniques are scattered over a number of texts and manuals, and the courses for database designers are often somewhat incomplete. The present paper shows a didactical experience which tackles this kind of limitations. In particular, the authors have prepared a textbook that includes twenty-one different index formats; it discusses advantages and disadvantages of each indexing technique, and has been positively validated during advanced courses on relational database design. 展开更多
关键词 database indexing techniques DB design non-traditional students didactical experience.
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Re-engineering of the forest stand database:case study of Bilahe Forestry Bureau,Inner Mongolia of China 被引量:1
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作者 陈文波 郑蕉 《Journal of Forestry Research》 SCIE CAS CSCD 2008年第3期231-234,共4页
The forest stand database of Bilahe Forestry Bureau, Inner Mongolia of China was taken as an example to demonstrate the whole process of building a temporal geodatabase by means of reengineering. The process was compo... The forest stand database of Bilahe Forestry Bureau, Inner Mongolia of China was taken as an example to demonstrate the whole process of building a temporal geodatabase by means of reengineering. The process was composed of establishing a conceptual data model from the initial database, constructing a logical database by means of mapping, and building a temporal geodatabase with the help of Computer-Aided Software Engineering (CASE) tool and Unified Markup Language (UML). The results showed that as the reengineered forest stand geodatabase was dynamic, it could easily store the historical data and answer time related questions by Structured Query Language (SQL), meanwhile, it maintains the integrity of database and eliminates the redundancy. 展开更多
关键词 RE-ENGINEERING spatial-temporal database CASE tool forest stand
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Spatial-temporal Changes of Vegetation Cover in Guizhou Province, Southern China 被引量:27
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作者 TIAN Yichao BAI Xiaoyong +2 位作者 WANG Shijie QIN Luoyi LI Yue 《Chinese Geographical Science》 SCIE CSCD 2017年第1期25-38,共14页
Guizhou Province is an important karst area in the world and a fragile ecological area in China. Ecological risk assessment is very necessary to be conducted in this region. This study investigates different character... Guizhou Province is an important karst area in the world and a fragile ecological area in China. Ecological risk assessment is very necessary to be conducted in this region. This study investigates different characteristics of the spatial-temporal changes of vegetation cover in Guizhou Province of Southern China using the data set of SPOT VEGETATION(1999–2015) at spatial resolution of 1-km and temporal resolution of 10-day. The coefficient of variation, the Theil-Sen median trend analysis, and the Mann-Kendall test are used to investigate the spatial-temporal change of vegetation cover and its future trend. Results show that: 1) the spatial distribution pattern of vegetation cover in Guizhou Plateau is high in the east whereas low in the west. The average annual normalized difference vegetation index(NDVI) from west to east is higher than that from south to north. 2) Average annual NDVI improved obviously in the past 17 years. The growth rate of average annual NDVI is 0.028/10 yr, which is slower than that of vegetation in the country(0.048/10 yr) from 1998 to 2007. Average annual NDVI in karst area is lower than that in non-karst area. However, the growing rate of average annual NDVI in karst area(0.030/10 yr) is faster than that in non-karst area(0.023/10 yr), indicating that vegetation coverage increases more rapidly in karst area. 3) Vegetation coverage in the study area is stable overall, but fluctuates in the local scales. 4) Vegetation coverage presents a continuous increasing trend. The Hurst exponent of NDVI in different vegetation types has an obvious threshold in various elevations. 5) The proportion of vegetation cover with sustainable increase is higher than that of vegetation cover with sustainable decrease. The improvement in vegetation cover may expand to most parts of the study area. 展开更多
关键词 vegetation cover spatial-temporal change trends analysis normalized difference vegetation index(NDVI) Hurst exponent Guizhou Province China
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(r,QI)-Transform:Reversible Data Anonymity Based on Numeric Type of Data in Outsourced Database
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作者 Iuon-Chang Lin Yang-Te Lee Chen-Yang Cheng 《Journal of Electronic Science and Technology》 CAS CSCD 2017年第3期222-230,共9页
An outsource database is a database service provided by cloud computing companies.Using the outsource database can reduce the hardware and software's cost and also get more efficient and reliable data processing capa... An outsource database is a database service provided by cloud computing companies.Using the outsource database can reduce the hardware and software's cost and also get more efficient and reliable data processing capacity.However,the outsource database still has some challenges.If the service provider does not have sufficient confidence,there is the possibility of data leakage.The data may has user's privacy,so data leakage may cause data privacy leak.Based on this factor,to protect the privacy of data in the outsource database becomes very important.In the past,scholars have proposed k-anonymity to protect data privacy in the database.It lets data become anonymous to avoid data privacy leak.But k-anonymity has some problems,it is irreversible,and easier to be attacked by homogeneity attack and background knowledge attack.Later on,scholars have proposed some studies to solve homogeneity attack and background knowledge attack.But their studies still cannot recover back to the original data.In this paper,we propose a data anonymity method.It can be reversible and also prevent those two attacks.Our study is based on the proposed r-transform.It can be used on the numeric type of attributes in the outsource database.In the experiment,we discussed the time required to anonymize and recover data.Furthermore,we investigated the defense against homogeneous attack and background knowledge attack.At the end,we summarized the proposed method and future researches. 展开更多
关键词 index Terms--Cloud database data anonymity database privacy outsource database REVERSIBLE
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The Valvular Heart Disease-specific Age-adjusted Comorbidity Index(VHD-ACI)score in patients with moderate or severe valvular heart disease
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作者 Mu-Rong XIE Bin ZHANG +14 位作者 Yun-Qing YE Zhe LI Qing-Rong LIU Zhen-Yan ZHAO Jun-Xing LV De-Jing FENG Qing-Hao ZHAO Hai-Tong ZHANG Zhen-Ya DUAN Bin-Cheng WANG Shuai GUO Yan-Yan ZHAO Run-Lin GAO Hai-Yan XU Yong-Jian WU 《Journal of Geriatric Cardiology》 2025年第9期759-774,共16页
Background Based on the China-VHD database,this study sought to develop and validate a Valvular Heart Disease-specific Age-adjusted Comorbidity Index(VHD-ACI)for predicting mortality risk in patients with VHD.Methods&... Background Based on the China-VHD database,this study sought to develop and validate a Valvular Heart Disease-specific Age-adjusted Comorbidity Index(VHD-ACI)for predicting mortality risk in patients with VHD.Methods&Results The China-VHD study was a nationwide,multi-centre multi-centre cohort study enrolling 13,917 patients with moderate or severe VHD across 46 medical centres in China between April-June 2018.After excluding cases with missing key variables,11,459 patients were retained for final analysis.The primary endpoint was 2-year all-cause mortality,with 941 deaths(10.0%)observed during follow-up.The VHD-ACI was derived after identifying 13 independent mortality predictors:cardiomyopathy,myocardial infarction,chronic obstructive pulmonary disease,pulmonary artery hypertension,low body weight,anaemia,hypoalbuminaemia,renal insufficiency,moderate/severe hepatic dysfunction,heart failure,cancer,NYHA functional class and age.The index exhibited good discrimination(AUC,0.79)and calibration(Brier score,0.062)in the total cohort,outperforming both EuroSCORE II and ACCI(P<0.001 for comparison).Internal validation through 100 bootstrap iterations yielded a C statistic of 0.694(95%CI:0.665−0.723)for 2-year mortality prediction.VHD-ACI scores,as a continuous variable(VHD-ACI score:adjusted HR(95%CI):1.263(1.245-1.282),P<0.001)or categorized using thresholds determined by the Yoden index(VHDACI≥9 vs.<9,adjusted HR(95%CI):6.216(5.378-7.184),P<0.001),were independently associated with mortality.The prognostic performance remained consistent across all VHD subtypes(aortic stenosis,aortic regurgitation,mitral stenosis,mitral regurgitation,tricuspid valve disease,mixed aortic/mitral valve disease and multiple VHD),and clinical subgroups stratified by therapeutic strategy,LVEF status(preserved vs.reduced),disease severity and etiology.Conclusion The VHD-ACI is a simple 13-comorbidity algorithm for the prediction of mortality in VHD patients and providing a simple and rapid tool for risk stratification. 展开更多
关键词 Valvular heart disease Age adjusted comorbidity index Mortality prediction Risk stratification China VHD database Prognostic performance
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身体圆度指数与腰痛之间的关系
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作者 王倩 马艳 +3 位作者 李梦圆 刘兴朝 张梦雨 于少泓 《颈腰痛杂志》 2026年第1期118-124,共7页
目的 本研究旨在探究身体圆度指数(BRI)与腰痛的关联,识别关键风险阈值,为内脏肥胖相关腰痛的防控提供依据。方法 基于美国国家健康与营养检查调查(NHANES)的数据,纳入10 745名20岁以上的成人。使用逻辑回归模型分析BRI(连续变量及四分... 目的 本研究旨在探究身体圆度指数(BRI)与腰痛的关联,识别关键风险阈值,为内脏肥胖相关腰痛的防控提供依据。方法 基于美国国家健康与营养检查调查(NHANES)的数据,纳入10 745名20岁以上的成人。使用逻辑回归模型分析BRI(连续变量及四分位分组)与腰痛之间的关联;利用限制性立方样条探究两者的非线性关系,通过似然比检验验证阈值效应;采取亚组分析检验代谢疾病、社会因素的交互作用。结果 BRI每增加1单位,腰痛风险显著升高7%(全模型调整后比值比(OR)=1.07, 95%CI:1.05~1.10),最高四分位组(Q4)风险较Q1增加30%(OR=1.30, 95%CI:1.16~1.46)。BRI与腰痛存在非线性关系,拐点为2.386,当BRI<2.386时风险降低53%(OR=0.47, 95%CI:0.23~0.98),当BRI≥2.386时每单位风险升高9%(OR=1.09, 95%CI:1.06~1.11),且效应在糖尿病患者、高中以下学历者及其他西班牙裔人群中增强。结论 BRI是腰痛的独立风险预测因子,二者存在非线性关系。BRI>2.386可作为早期干预的风险阈值,为肥胖相关性腰痛的风险分层提供新工具。 展开更多
关键词 身体圆度指数 内脏脂肪 中心性肥胖 腰痛 NHANES数据库 横断面研究
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AAindex数据库中傅里叶方法的多重氨基酸指数选择 被引量:1
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作者 赵剑 许金涛 《数据采集与处理》 CSCD 北大核心 2013年第5期643-649,共7页
波谱学方法研究蛋白质时,蛋白质序列的特征频率与蛋白质的位点、功能、空间结构对应。基于时间序列傅里叶变换的交叉谱原理,本文提出的"一个蛋白质关于多种氨基酸指数的一致谱"能够获取一个或多个蛋白质序列较显著的特征频率... 波谱学方法研究蛋白质时,蛋白质序列的特征频率与蛋白质的位点、功能、空间结构对应。基于时间序列傅里叶变换的交叉谱原理,本文提出的"一个蛋白质关于多种氨基酸指数的一致谱"能够获取一个或多个蛋白质序列较显著的特征频率,再由特征频率去筛选与之对应的氨基酸指数。该方法与Lazovic'的筛选方法和筛选意义不同。结果显示,筛选出的氨基酸指数对应的性质多数与蛋白质的空间结构性质有关。蛋白质特征频率也许是用于特征提取的好方法,氨基酸指数筛选可被看作蛋白质数字表达的一种优化。 展开更多
关键词 氨基酸指数数据库 傅里叶变换 特征频率 氨基酸指数筛选 信噪比
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Program Development and Implementation of Landscape Pattern Indexes for Land Use Based on RS
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作者 谢宏全 戴娣 《Journal of Landscape Research》 2011年第8期26-27,46,共3页
Interpretation results of RS images were taken as the foundation, ETM RS images of July 15, 2009 as the data source, ENVI was applied for the preprocessing, Arc GIS used to finish the interpretation, master data obtai... Interpretation results of RS images were taken as the foundation, ETM RS images of July 15, 2009 as the data source, ENVI was applied for the preprocessing, Arc GIS used to finish the interpretation, master data obtained, and VB used to complete program development. 12 representative landscape pattern indexes were selected, Excel data used to create Access database, and VB used to complete the program development. Selection of landscape pattern indexes, program development process and program usage were summarized, through comparing its results with Excel calculation results, it was found that calculation results of this program were correct, the usage was convenient, so needs of most users could be satisfied. 展开更多
关键词 REMOTE SENSING LANDSCAPE PATTERN indexes database Program development
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高校建设项目造价指标库构建与应用
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作者 杨成艳 薛能资 《山西建筑》 2026年第2期178-180,193,共4页
随着高校“双一流”建设的深入,各高校呈现多校区协同发展趋势,由此带来建设项目的大幅增加,工程造价管理面临更多的挑战。构建高校建设项目造价指标库,对提高工程造价管控水平,提升资金使用效益有重要意义。基于已竣工项目造价信息搭... 随着高校“双一流”建设的深入,各高校呈现多校区协同发展趋势,由此带来建设项目的大幅增加,工程造价管理面临更多的挑战。构建高校建设项目造价指标库,对提高工程造价管控水平,提升资金使用效益有重要意义。基于已竣工项目造价信息搭建高校建设项目造价指标库框架,并以指标库为例,提出其设计及应用方法,从而推动高校建设的完善治理和科学管控,有利于后续项目投资决策、造价控制。 展开更多
关键词 高校建设项目 造价指标 造价数据库
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BioIndex:一种生物序列相似性查询的高效索引 被引量:1
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作者 邱伯仁 熊赟 朱扬勇 《计算机应用与软件》 CSCD 2009年第10期1-4,18,共5页
有效管理生物数据并提供高效的查询方法是生物信息处理的重要研究内容。BioSeg是一个新的生物序列数据模型。查询优化研究是生物数据库管理系统开发的重要内容之一。研究当前生物数据索引技术,针对BioSeg数据模型的特点和生物序列相似... 有效管理生物数据并提供高效的查询方法是生物信息处理的重要研究内容。BioSeg是一个新的生物序列数据模型。查询优化研究是生物数据库管理系统开发的重要内容之一。研究当前生物数据索引技术,针对BioSeg数据模型的特点和生物序列相似性查询需求设计了一种新的生物序列数据索引BioIndex,并设计相应的查询算法。首先,使用MEME(Multiple EM for Moeif Elicit-ation)算法挖掘生物序列集中的序列模式作为索引建立索引序列库;之后,在索引序列库中查找与查询序列最相似的索引序列,将其对应的序列集作为候选集;再在候选集中查找与查询序列最相似的序列。在真实生物序列数据集上的实验表明使用新的生物序列数据索引BioIndex的序列查询算法提高了序列查询的效率。 展开更多
关键词 索引 生物序列 生物数据库 数据模型 查询优化
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Evaluation indexes for symptom changes in Chinese medicine
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作者 Yiguo Wang Mingzhu Yu Qiming Zhang 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2014年第2期238-242,共5页
OBJECTIVE: To screen and summarize evaluation indexes for symptom changes in Chinese medicine(CM).METHODS: A case database was established based on information from subsequent patient visits from the case records of f... OBJECTIVE: To screen and summarize evaluation indexes for symptom changes in Chinese medicine(CM).METHODS: A case database was established based on information from subsequent patient visits from the case records of famous doctors since 1866.Symptom change descriptions in the database were regarded as research materials. The evaluation indexes of the symptom changes were screened and summarized.RESULTS: In total, 243 evaluation indexes for 256symptoms were summarized. Among them, common symptoms were frequency, quantity, degree,mobility, color, and correlation with fatigue.CONCLUSION: There are many aspects to evaluating the changes in a symptom. Some symptoms occur with other simultaneous symptoms. The alleviation or aggravation of simultaneous symptoms could reflect the corresponding changes in a symptom. The changes of inducing factors are important to judging changes in symptoms. 展开更多
关键词 SYMPTOMS Medicine Chinese traditonal Evaluation index Inducing factor Subsequentvisits database
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About the Databases of Meteorological and Environmental Research
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《Meteorological and Environmental Research》 2025年第6期64-64,共1页
The journal of Meteorological and Environmental Research [ISSN: 2152-3940] has been included and stored by the following famous databases: CA, CABI, CSA, EBSCO, UPD, AGRIS, EA, Chinese Science and Technology Periodica... The journal of Meteorological and Environmental Research [ISSN: 2152-3940] has been included and stored by the following famous databases: CA, CABI, CSA, EBSCO, UPD, AGRIS, EA, Chinese Science and Technology Periodical Database, and CNKI, as well as Library of Congress, United States. 展开更多
关键词 stored library congress environmental research scientific databases journal meteorological environmental research meteorological research databases journal indexing
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A method for improving the accuracy of automatic indexing of Chinese-English mixed documents
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作者 Yan ZHAO Hui SHI 《Chinese Journal of Library and Information Science》 2012年第4期77-92,共16页
Purpose: The thrust of this paper is to present a method for improving the accuracy of automatic indexing of Chinese-English mixed documents.Design/methodology/approach: Based on the inherent characteristics of Chines... Purpose: The thrust of this paper is to present a method for improving the accuracy of automatic indexing of Chinese-English mixed documents.Design/methodology/approach: Based on the inherent characteristics of Chinese-English mixed texts and the cybernetics theory,we proposed an integrated control method for indexing documents. It consists of 'feed-forward control','in-progress control' and 'feed-back control',aiming at improving the accuracy of automatic indexing of Chinese-English mixed documents. An experiment was conducted to investigate the effect of our proposed method.Findings: This method distinguishes Chinese and English documents in grammatical structures and word formation rules. Through the implementation of this method in the three phases of automatic indexing for the Chinese-English mixed documents,the results were encouraging. The precision increased from 88.54% to 97.10% and recall improved from97.37% to 99.47%.Research limitations: The indexing method is relatively complicated and the whole indexing process requires substantial human intervention. Due to pattern matching based on a bruteforce(BF) approach,the indexing efficiency has been reduced to some extent.Practical implications: The research is of both theoretical significance and practical value in improving the accuracy of automatic indexing of multilingual documents(not confined to Chinese-English mixed documents). The proposed method will benefit not only the indexing of life science documents but also the indexing of documents in other subject areas.Originality/value: So far,few studies have been published about the method for increasing the accuracy of multilingual automatic indexing. This study will provide insights into the automatic indexing of multilingual documents,especially Chinese-English mixed documents. 展开更多
关键词 Chinese-English mixed documents String matching Accuracy of automatic indexing CYBERNETICS Dedicated hepatitis B virus(HBV) database
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Learned Index和B-Tree在不同分布数据上的性能对比及优化
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作者 沈怡琪 蔡鹏 刘松灵 《计算机应用》 CSCD 北大核心 2023年第S01期100-106,共7页
Learned Index是一种通过训练模型来建立输入数据和存储位置之间映射关系的索引,它能学习到数据间分布的信息,而不同的数据分布将影响模型训练准确率和模型复杂度之间的平衡。为了探索Learned Index适用的场景,使用不同分布、不同数据... Learned Index是一种通过训练模型来建立输入数据和存储位置之间映射关系的索引,它能学习到数据间分布的信息,而不同的数据分布将影响模型训练准确率和模型复杂度之间的平衡。为了探索Learned Index适用的场景,使用不同分布、不同数据量的数据对它和加以优化的可更新的自适应学习索引(ALEX)进行性能测试,并与B-Tree进行对比,最终发现Learned Index构建大批量数据的索引时间比B-Tree短,读操作性能、存储空间大小有明显的优势,但写操作性能较差,因此得出Learned Index更适用于大数据情景下的在线分析处理(OLAP)数据库,用于静态数据的存储和查询操作的结论。基于B-Tree的索引结构,对初版Learned Index的结构进行了优化和调整,最终使优化后Learned Index在大批量数据的读写操作性能上有明显提高,其中读操作最高达到原版Learned Index的2倍,写操作最高达到原版的3倍。 展开更多
关键词 Learned index B-TREE 可更新的自适应学习索引 在线分析处理数据库 静态数据 优化调整
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一种基于MongoDB的分布式存储与查询方法
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作者 李俊杰 范冲 +2 位作者 赵丹丹 李盘盘 胡海立 《海洋测绘》 北大核心 2025年第4期78-82,共5页
针对MongoDB数据库面对海量海洋环境数据访问时,存在数据查询效率偏低的问题,本文提出了一种基于MongoDB分布存储模型与索引构建的方法,用于提升海洋环境数据的查询效率。首先基于MongoDB数据库分片分区策略,将不同类型的海洋环境数据... 针对MongoDB数据库面对海量海洋环境数据访问时,存在数据查询效率偏低的问题,本文提出了一种基于MongoDB分布存储模型与索引构建的方法,用于提升海洋环境数据的查询效率。首先基于MongoDB数据库分片分区策略,将不同类型的海洋环境数据进行分布存储,然后针对海洋环境数据的时空特征,提出了一种索引结构,该结构利用S2算法和Hilbert曲线,进行数据维度的降低,进而提高海量海洋环境数据的查询效率。实验结果表明,本文方法相较于MongoDB利用复合索引在点查询时效率提升1.65倍,在范围查询时效率提升5倍,能够有效提升海洋环境数据查询效率。 展开更多
关键词 分布式存储 MongoDB数据库 索引构建 S2算法 HILBERT曲线
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基于国家健康与营养调查数据库研究全身免疫炎症指数与慢性肾脏病患者肌少症的关联
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作者 黄家懿 汪思 +1 位作者 吴志山 丁悦凤 《临床肾脏病杂志》 2025年第11期929-935,共7页
目的基于国家健康与营养调查(national health and nutrition examination survey,NHANES)数据库探索全身免疫炎症指数(systemic immune-inflammation index,SII)与慢性肾脏病(chronic kidney disease,CKD)患者肌少症的关系。方法收集1... 目的基于国家健康与营养调查(national health and nutrition examination survey,NHANES)数据库探索全身免疫炎症指数(systemic immune-inflammation index,SII)与慢性肾脏病(chronic kidney disease,CKD)患者肌少症的关系。方法收集1999年至2006年、2011年至2018年美国NHANES网站公开的数据,共纳入CKD患者4742例。将CKD患者根据SII四分位数分为SII Q1组、SII Q2组、SII Q3组、SII Q4组,比较组间年龄、种族等指标及肌少症患病率的差异。采用Logistic回归分析SII与肌少症的相关性,行趋势分析并分析性别、种族与SII的交互作用。采用限制性立方样条图(restricted cubic spline,RCS)分析SII与肌少症风险的潜在连续关系。结果本研究共纳入CKD患者4742例。SII Q1组、SII Q2组、SII Q3组、SII Q4组CKD患者年龄、种族、性别、教育情况、体重指数、吸烟、高血压、糖尿病、心血管疾病比例、三酰甘油(triglycerides,TG)、总胆固醇(total cholesterol,TC)、尿白蛋白、尿肌酐、血清白蛋白、C反应蛋白(C-reactionprotein,CRP)、血红蛋白比较,差异有统计学意义(P<0.05)。整体肌少症患病率为20.60%,SII Q1组(17.20%)、SII Q2组(18.65%)、SII Q3组(21.01%)、SII Q4组(25.55%)差异有统计学意义(χ^(2)=29.007,P<0.001)。调整年龄、种族等混杂因素后,SII与CKD相关肌少症仍显著相关(OR=2.426,95%CI:1.913~3.076,P<0.05);与SII Q1组相比,SII Q2组(OR=1.290,95%CI:1.007~1.653)、SII Q3组(OR=2.898,95%CI:2.241~3.748)、SII Q4组(OR=4.629,95%CI:3.543~6.048)肌少症风险仍显著增高(P<0.05),且OR值呈增加趋势(P_(趋势)<0.05)。在不同性别、种族亚组中,CKD患者肌少症风险均随SII的增加而增加(P_(趋势)<0.001,P_(交互)>0.05)。RCS分析显示,在CKD患者中,SII与肌少症风险呈非线性相关性(P_(非线性)=0.003),当SII>483.42×10^(9)/L时,SII越高,肌少症风险越高。结论在CKD患者中SII与肌少症风险密切相关,当SII>483.42×10^(9)/L时,SII越高,肌少症风险越高。 展开更多
关键词 慢性肾脏病 肌少症 全身免疫炎症指数 国家健康与营养调查数据库
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