Mining for Attribute Definitions in a Distributed Two-Layered DB System
作者:Zbigniew W. Ras, Jan M. Żytkow
摘要
Empirical equations are an important class of regularities that can be discovered in databases. We concentrate on the role of equations as definitions of attribute values. Such definitions can be used in many ways in a single database and for transfer of knowledge between databases. We present a quest for equations that can be used as definitions of an attribute in a given database. That quest triggers a discovery mechanism that specializes in searching recursively a system of databases and returns a set of partial definitions. We introduce the notion of shared operational semantics. It is founded on an equation-based system of partial definitions and it gives necessary foundations for designing local query answering systems in a distributed two-layered information system (D2LIS). The knowledge exchange between two sites of D2LIS may only improve an equation-based system of partial definitions at each of these sites. At the same time the shared operational semantics will better interpret user queries. Operational semantics augments the earlier developed semantics for rules used as attribute definitions. To put the shared operational semantics on a firm theoretical foundation we give a formal interpretation of queries which justifies empirical equations in their definitional role.
论文关键词:knowledge discovery, distributed knowledge systems, knowledge interchange, operational semantics, two-layered databases
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论文官网地址:https://doi.org/10.1023/A:1008779617939