20,668 research outputs found
FP-tree and COFI Based Approach for Mining of Multiple Level Association Rules in Large Databases
In recent years, discovery of association rules among itemsets in a large
database has been described as an important database-mining problem. The
problem of discovering association rules has received considerable research
attention and several algorithms for mining frequent itemsets have been
developed. Many algorithms have been proposed to discover rules at single
concept level. However, mining association rules at multiple concept levels may
lead to the discovery of more specific and concrete knowledge from data. The
discovery of multiple level association rules is very much useful in many
applications. In most of the studies for multiple level association rule
mining, the database is scanned repeatedly which affects the efficiency of
mining process. In this research paper, a new method for discovering multilevel
association rules is proposed. It is based on FP-tree structure and uses
cooccurrence frequent item tree to find frequent items in multilevel concept
hierarchy.Comment: Pages IEEE format, International Journal of Computer Science and
Information Security, IJCSIS, Vol. 7 No. 2, February 2010, USA. ISSN 1947
5500, http://sites.google.com/site/ijcsis
The Contextual Database of the Generations and Gender Program
The increasing recognition that the study of human behaviors has to take into account the multiple contexts in which they occur has opened a promising research avenue in social sciences. It also presents new challenges, e.g., to complement micro-level surveys with the collection of meaningful contextual data within a common conceptual framework. The Contextual Database of the Generations and Gender Program aims at responding to the new data demands by providing a comparative collection of around 210 variables on a national and sub-national level, thus complementing the individual-level data collected in the Generations and Gender Survey.World, comparative analysis, data banks
The contextual database of the Generations and Gender Program: overview, conceptual framework and the link to the Generations and Gender Survey
This paper follows two aims. First it intends to give an overview of the contextual database of the Generations and Gender Program and how it is linked to the Generations and Gender Survey. Secondly, it provides a documentation of the approaches taken towards the conceptual definition and construction of the database. The document consists of two parts. The first gives a brief description of the underlying ideas of the database and the approach taken in order to develop its conceptual framework and construct the database. The second part is a note on the link between the Generations and Gender Survey and the contextual database. Starting from the GGS questionnaire, the main interfaces between micro data and contextual domains are investigated.data collection
Authorization and access control of application data in Workflow systems
Workflow Management Systems (WfMSs) are used to support the modeling and coordinated execution of business processes within an organization or across organizational boundaries. Although some research efforts have addressed requirements for authorization and access control for workflow systems, little attention has been paid to the requirements as they apply to application data accessed or managed by WfMSs. In this paper, we discuss key access control requirements for application data in workflow applications using examples from the healthcare domain, introduce a classification of application data used in workflow systems by analyzing their sources, and then propose a comprehensive data authorization and access control mechanism for WfMSs. This involves four aspects: role, task, process instance-based user group, and data content. For implementation, a predicate-based access control method is used. We believe that the proposed model is applicable to workflow applications and WfMSs with diverse access control requirements
Logical Foundations of Multilevel Databases
International audienceIn this paper, we propose a formal model for multilevel databases. This model aims at being a generic model, that is it can be interpreted for any kind of database (relational, object-oriented...). Our model has three layers. The first layer corresponds to a model for a non-protected database. The second layer corresponds to a model for a multilevel database. In this second layer, we propose a list of theorems that must be respected in order to build a secure multilevel database. We also propose a new solution to manage cover stories without using the ambiguous technique of polyinstantiation. The third layer corresponds to a model for a MultiView database, that is, a database that provides at each security level a consistent view of the multilevel database. Finally, as an illustration, we interpret our 3-layer model in the case of an object-oriented database
An object-oriented approach to security policies and their access controls for database management
The constructs of the object-oriented data model seem to be good candidates for the specifications of the need-to-know and multilevel security policies and their respective access control requirements. This report demonstrates such specifications. The implication of this demonstration may be profound, since for the first time multiple security policies and their respective access controls may be realized and supported in a single object- oriented database management systemhttp://archive.org/details/objectorientedap00hsiaN
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