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.
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
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
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
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
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
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
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
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
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
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
现有的索引选择方法存在诸多局限性.首先,大多数方法考虑场景较为单一,不能针对特定数据模态选择合适的索引结构,进而无法有效应对海量多模态数据;其次,现有方法未考虑索引选择时索引构建的代价,无法有效应对动态的工作负载.针对上述问...现有的索引选择方法存在诸多局限性.首先,大多数方法考虑场景较为单一,不能针对特定数据模态选择合适的索引结构,进而无法有效应对海量多模态数据;其次,现有方法未考虑索引选择时索引构建的代价,无法有效应对动态的工作负载.针对上述问题,提出一种面向多模态数据的智能高效索引选择模型APE-X DQN(Distributed prioritized experience replay in deep Q-network),称为AP-IS(APE-X DQN for index selection).AP-IS设计了新型索引集编码和SQL语句编码方法,该方法使AP-IS在感知多模态数据的同时兼顾索引结构本身的特性,极大地降低了索引的存储代价.APIS集成新型索引效益评估方法,在优化强化学习奖励机制的同时,监控数据库工作负载的执行状态,保证动态工作负载下AP-IS在时间和空间上的优化效果.在真实多模态数据集上进行大量实验,验证了AP-IS在工作负载的延迟、存储代价和训练效率等方面的性能,结果均明显优于最新索引选择方法.展开更多
文摘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.
基金Supported bythe National High Technology of 863Project (2002AA1Z2308 ,2002AA118030)
文摘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.
文摘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.
文摘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.
文摘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.
基金supported by the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences(No.2017-12M-3-002)the National Key R&D Program of China(No.2020YFC2008100).
文摘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.
基金Supported by Social Development Program of Lianyungang Bureau of Science and Technology,Jiangsu Province:RS-based Research on the Eco-environment Evolution of Coastal Regions in Lianyungang(SH0811)~~
文摘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.
文摘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。
基金Supported by the National Natural Science Foundation of China (the Diagnostic Points of General Syndrome Factors on the Symptomatic Units and their Clinical Characteristics,No.81001500)National Program of Science and Technology Development (the Research on Sweating Pattern Recognition of Chinese Medicine and the Development of High-Precision Detection Device,No.2012 BAI25B07)
文摘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.
文摘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.
基金supported by the Shanghai International Studies University(Grant No.:2011114061)
文摘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.
文摘现有的索引选择方法存在诸多局限性.首先,大多数方法考虑场景较为单一,不能针对特定数据模态选择合适的索引结构,进而无法有效应对海量多模态数据;其次,现有方法未考虑索引选择时索引构建的代价,无法有效应对动态的工作负载.针对上述问题,提出一种面向多模态数据的智能高效索引选择模型APE-X DQN(Distributed prioritized experience replay in deep Q-network),称为AP-IS(APE-X DQN for index selection).AP-IS设计了新型索引集编码和SQL语句编码方法,该方法使AP-IS在感知多模态数据的同时兼顾索引结构本身的特性,极大地降低了索引的存储代价.APIS集成新型索引效益评估方法,在优化强化学习奖励机制的同时,监控数据库工作负载的执行状态,保证动态工作负载下AP-IS在时间和空间上的优化效果.在真实多模态数据集上进行大量实验,验证了AP-IS在工作负载的延迟、存储代价和训练效率等方面的性能,结果均明显优于最新索引选择方法.
