The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Elizabeth A. Unger - One of the best experts on this subject based on the ideXlab platform.
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Integrity in object-oriented database systems
Computers & Security, 1993Co-Authors: James M. Slack, Elizabeth A. UngerAbstract:This paper develops a model of integrity for object-oriented database management systems. The integrity system is layered over an extended object-oriented data model. The resulting model is shown to handle common state integrity constraints, including domain, key, and structural constraints. This model can enforce value-based functional dependencies from the relational model, both within an object and across object classes. A new Relationship structural constraint, Reference Relationship, is presented which generalizes 1:1, 1:N, and N:M constraints in addition to total versus partial participation.
James M. Slack - One of the best experts on this subject based on the ideXlab platform.
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Integrity in object-oriented database systems
Computers & Security, 1993Co-Authors: James M. Slack, Elizabeth A. UngerAbstract:This paper develops a model of integrity for object-oriented database management systems. The integrity system is layered over an extended object-oriented data model. The resulting model is shown to handle common state integrity constraints, including domain, key, and structural constraints. This model can enforce value-based functional dependencies from the relational model, both within an object and across object classes. A new Relationship structural constraint, Reference Relationship, is presented which generalizes 1:1, 1:N, and N:M constraints in addition to total versus partial participation.
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Object-oriented database integrity
1992Co-Authors: James M. SlackAbstract:There is a growing interest in object-oriented databases for computer aided design, engineering design, office automation, forms, and multimedia applications. Most of these applications have requirements for integrity and many have additional secrecy requirements. Integrity and secrecy mechanisms are best implemented in the database management system so they are uniformly enforced across applications. At present there is not a formal object-oriented data model which is generally agreed upon. The first result of this research is a new, simple formal model of object structure, inheritance, and method invocation for object-oriented databases. In this model, both classes and instances are objects. For better integrity and secrecy, attributes are not accessible outside their respective classes. They must be accessed through methods of the class; this is true even for descendants of a class. Therefore, the accessibility of methods determines the inheritance mechanism. The model supports multiple inheritance. Both the model and its inheritance mechanism are shown to be sound and complete. The second result of this research is a model of integrity for object-oriented database management systems based on first order predicate calculus. The formal object-oriented data model is extended with standard operators (including two aggregation operators). The integrity system is layered over this extended model. The resulting model is shown to handle common state integrity constraints, including domain, key, and structural constraints. This model can enforce value-based functional dependencies from the relational model, both within an object and across object classes. A new Relationship structural constraint, Reference Relationship, is presented which generalizes 1:1, 1:N, and N:M constraints in addition to total versus partial participation. The third result of this research is an approach to integrity and secrecy in object-oriented database systems based on protected groups. A protected group is a set of objects which will only accept messages from one or more interface objects. We show how discretionary access control, data integrity, access integrity, and the Clark-Wilson integrity model can be implemented with this approach. We also discuss how Abrams' Generalized Framework for Access Control may be implemented with this approach.
Degan Zhang - One of the best experts on this subject based on the ideXlab platform.
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DASFAA Workshops - Identifying Reference Relationship of Desktop Files Based on Access Logs.
Database Systems for Advanced Applications, 2019Co-Authors: Xun Zhang, Yuan Wang, Degan ZhangAbstract:When writing a document, people sometimes refer to other files’ information such as a picture, a phone number, an email address, a table, a document and so on, therefore Reference becomes a natural Relationship among desktop files which can be utilized to help people re-finding personal information or identifying information linage. Therefore how to identify Reference Relationship is an interesting and valuable topic. In this paper, we propose an access log-based method to identify the Relationship. Firstly we propose a method to generate access logs by monitoring user desktop operations, and implement a prototype based on the method, and collect several persons’ access logs by running it in personal computers. Then we propose an access logs-based method to identify Reference Relationship of desktop files. The experimental results verify the effectiveness and efficiency of our methods.
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identifying Reference Relationship of desktop files based on access logs
Database Systems for Advanced Applications, 2019Co-Authors: Yukun Li, Xun Zhang, Jie Li, Yuan Wang, Degan ZhangAbstract:When writing a document, people sometimes refer to other files’ information such as a picture, a phone number, an email address, a table, a document and so on, therefore Reference becomes a natural Relationship among desktop files which can be utilized to help people re-finding personal information or identifying information linage. Therefore how to identify Reference Relationship is an interesting and valuable topic. In this paper, we propose an access log-based method to identify the Relationship. Firstly we propose a method to generate access logs by monitoring user desktop operations, and implement a prototype based on the method, and collect several persons’ access logs by running it in personal computers. Then we propose an access logs-based method to identify Reference Relationship of desktop files. The experimental results verify the effectiveness and efficiency of our methods.
Peiqiang Zhao - One of the best experts on this subject based on the ideXlab platform.
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a social network analysis of changes in china s education policy information transmission system 1978 2013
Higher Education Policy, 2020Co-Authors: Cui Huang, Shutao Wang, Peiqiang ZhaoAbstract:This study examines the evolution of China’s education policy transmission system and analyzes its influencing factors. Data were collected from 5793 policy documents issued by the Chinese central government from 1978 to 2013. Using policy document bibliometrics and social network analysis, we studied the “citing-cited” policy Reference Relationship to undertake an in-depth characterization of the different stages of education policy and reform since China’s economic reform and opening up in 1978. We determined changing trends in the education policy transmission system through using an environment-actors-institutions framework to uncover the factors behind such trends. Results showed that China’s education policy transmission system has experienced a rapid expansion in the last few decades, and that characteristics are distinct from onetime period to another. Central governance ideologies had a relatively strong impact on the popular themes and topics of education policy in different stages. Meanwhile, the policy-issuing institutions played a significant role in the effectiveness of a certain policy measure. Additionally, the supervisory institution was an important factor that affected the degree of centrality in the evolving education policy network.
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A Social Network Analysis of Changes in China’s Education Policy Information Transmission System (1978–2013)
Higher Education Policy, 2018Co-Authors: Cui Huang, Shutao Wang, Peiqiang ZhaoAbstract:This study examines the evolution of China’s education policy transmission system and analyzes its influencing factors. Data were collected from 5793 policy documents issued by the Chinese central government from 1978 to 2013. Using policy document bibliometrics and social network analysis, we studied the “citing-cited” policy Reference Relationship to undertake an in-depth characterization of the different stages of education policy and reform since China’s economic reform and opening up in 1978. We determined changing trends in the education policy transmission system through using an environment-actors-institutions framework to uncover the factors behind such trends. Results showed that China’s education policy transmission system has experienced a rapid expansion in the last few decades, and that characteristics are distinct from onetime period to another. Central governance ideologies had a relatively strong impact on the popular themes and topics of education policy in different stages. Meanwhile, the policy-issuing institutions played a significant role in the effectiveness of a certain policy measure. Additionally, the supervisory institution was an important factor that affected the degree of centrality in the evolving education policy network.
Zhijun Yan - One of the best experts on this subject based on the ideXlab platform.
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Mining medical related temporal information from patients’ self-description
International Journal of Crowd Science, 2017Co-Authors: Lichao Zhu, Hangzhou Yang, Zhijun YanAbstract:Purpose The purpose of this paper is to develop a new method to extract medical temporal information from online health communities. Design/methodology/approach The authors trained a conditional random-filed model for the extraction of temporal expressions. The temporal relation identification is considered as a classification task and several support vector machine classifiers are built in the proposed method. For the model training, the authors extracted some high-level semantic features including co-Reference Relationship of medical concepts and the semantic similarity among words. Findings For the extraction of TIMEX, the authors find that well-formatted expressions are easy to recognize, and the main challenge is the relative TIMEX such as “three days after onset”. It also shows the same difficulty for normalization of absolute date or well-formatted duration, whereas frequency is easier to be normalized. For the identification of DocTimeRel, the result is fairly well, and the relation is difficult to identify when it involves a relative TIMEX or a hypothetical concept. Originality/value The authors proposed a new method to extract temporal information from the online clinical data and evaluated the usefulness of different level of syntactic features in this task.
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ICCSE - Extracting Temporal Information from Online Health Communities
Proceedings of the 2nd International Conference on Crowd Science and Engineering - ICCSE'17, 2017Co-Authors: Lichao Zhu, Hangzhou Yang, Zhijun YanAbstract:In order to extract structured medical information and related temporal information from online health communities, an integrate method based on syntactic parsing was proposed in this paper. We treated the extraction of medical and temporal phrases as a series tagging problem and trained two conditional random fled model respectively. The temporal relation identification is considered as a classification task and several support vector machine classifiers are built in the proposed method. For the feature engineering, we extracted some high level semantic features including co-Reference Relationship of medical concepts and the semantic similarity among tokens. The experiment results show that the proposed method has good performance in both phrase recognition and relation classification and could helped to automatically display a patient's clinical situation in chronological order.