caa a22 4500 475799240 CHVBK 20180406123732.0 cr unu---uuuuu 170329e20000301xx s 000 0 eng 10.1023/A:1008779617939 doi (NATIONALLICENCE)springer-10.1023/A:1008779617939 Mining for Attribute Definitions in a Distributed Two-Layered DB System [Elektronische Daten] [Zbigniew Ras, Jan Żytkow] 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. Kluwer Academic Publishers, 2000 knowledge discovery nationallicence distributed knowledge systems nationallicence knowledge interchange nationallicence operational semantics nationallicence two-layered databases nationallicence Ras Zbigniew Computer Science Department, University of North Carolina, 28223, Charlotte, N.C aut Żytkow Jan Institute of Computer Science, Polish Academy of Sciences, 01-237, Warsaw, Poland aut Journal of Intelligent Information Systems Kluwer Academic Publishers 14/2-3(2000-03-01), 115-130 0925-9902 14:2-3<115 2000 14 10844 https://doi.org/10.1023/A:1008779617939 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1008779617939 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ras Zbigniew Computer Science Department, University of North Carolina, 28223, Charlotte, N.C aut NATIONALLICENCE 700 1- Żytkow Jan Institute of Computer Science, Polish Academy of Sciences, 01-237, Warsaw, Poland aut NATIONALLICENCE 773 0- Journal of Intelligent Information Systems Kluwer Academic Publishers 14/2-3(2000-03-01), 115-130 0925-9902 14:2-3<115 2000 14 10844 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer