Illarramendi, A., Blanco, J. M., and Goni, A., "A uniform approach to design a federated system using back," Proc. Terminological Logic Users Workshop, KIT--Report 95, Technische Universitat Berlin, Berlin, October, 1991, pp. 61--85.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... broader theoretical community [3, 8, 9, 27, 33] More broadly, both within and outside of medicine, description logics and their relations are being seen increasingly as the natural means of creating reusable terminological structure, or ontologies, for federating heterogeneous knowledge sources [12, 19, 25] and there is intense research on uniting description logics and object oriented databases [4, 13, 24] Transitivity and necessary statements (concept Inclusions) Two key difficulties There are two properties which are known to produce difficulties which are of particular importance for ....

A. Illarramendi, J. Blanco, A. Goni, A uniform approach to design a federated system using BACK, Terminological Logic Users Workshop , Berlin,

....terminological system with a customized persistency mechanism (though not for a very expressive language) has been described in [7] The other approach to scaling up the size of potential KBs involves some kind of coupling to external databases. This direction is pursued in the AIMS project ( 1] [6]) and recently also by [2] 4] The primary motivation here is to access large, pre existing databases transparently via a rich domain model expressed in the description logic. In practice, this is achieved by translating concepts into database queries, and by thereby loading only those instances ....

....In fact, a genuinely persistent DL system acting as a server to applications and as a client to a variety of databases and other data sources is an appealing scenario. The conceptual modelling capabilities make a DL system an ideal candidate as a front end for heterogeneous data sources (cf. [6]) In this paper we describe a method for building a persistent index on externally stored instances which has proven to be effective as an extension to a pure in core system, but would be equally useful as part of an intrinsically persistent system that accesses external data. In both cases, ....

Illarramendi, A., Blanco, J.M., and Goni, A., A Uniform Approach To Design a Federated System Using BACK. Proceedings Terminological Logic Users Workshop, KIT Report 95, Technische Universitat Berlin, October 1991

....have to represent in the same formalism parts of the information which are represented in the Relational Model, and other parts represented in an Object Oriented Model. A better formalism for this purpose seems to be a Description Logic derived from KL1 (Blanco et al. Valencia 1992; Brachman 1977; Illaramendi, Blanco, Goni 1991). Even if the expressive power has strong limitations Borgida has shown in (Borgida 1995) that a substantial fragment of FOL can be translated into a Description Logic, namely first order sentences formed with unary and binary predicates, and with no more than three distinct variables. Moreover ....

Illaramendi, A.; Blanco, J.; and Goni, A. 1991. A uniform approach to design a federated system using BACK. In Proc. Terminological Logic Users Workshop.

....of the KB, etc. Full details of their translation language were not available at the time of writing, so a close comparison with qindl is not possible. Since using descriptions as queries for external data sources is not of primary concern, safety is not discussed in [9] Illarramendi, et al., [10] describe the use of back[14] as a tool to facilitate the integration of schemas from different databases into one federated database. back s classification assists in this process. Again, the main focus there is not the use of descriptions as queries. Finally, the design of the qindl ....

Illarramendi, A., Blanco, J., Go~ni, A., A Uniform Approach to Design A Federated System Using back, Terminological Logic Users Workshop Proceedings, KIT Report 95, Technische Universitat Berlin, October, 1991.

....data models. Special versions of DLs, such as the Entity Situation model [Bergamaschi et al. 1988] have been proposed as particularly appropriate for developing conceptual database models. DLs have also been proposed as tools for integrating the schema of disparate databases [Beck et al. 1992, Illamarendi et al. 1991] in situations such as heterogeneous databases. In addition to allowing more aspects of data semantics to be captured, the logic of DLs is also helpful in schema design because one can check the schema for consistency, as follows: suppose a concept specification requires that its instances be ....

Illamarendi, A., J. Blanco, A.Goni, "A uniform approach to the design of federated systems using back", Proc. Terminological Users Workshop, Berlin, October 1991, Tech. Report KIT 95, Technische Universitat Berlin.

....in many applications where access to data is required. We summarize some of these applications of DLs, though for a fuller survey the reader is directed to [11] The present work is directly motivated by the recent use of DLs as query languages to access data stored in relational databases [16, 2, 23]. There has been considerable research on the complexity of reasoning with descriptions, especially computing the subsumption (containment) relationship between them. Surprisingly little is known about their expressive power as query languages, in comparison with well known formalisms based on ....

....was done by treating them as special concepts) especially in natural language understanding applications. Not surprisingly, DLs are therefore useful for capturing the conceptual schema of databases, i.e. as data definition languages. A number of papers have explored this aspect, including [12, 7, 8, 23]; in fact, it is shown in [9] how the Entity Relationship and DAPLEX semantic models can be expressed in a DL. The benefits of having a logic of descriptions in this case include the ability to automatically organize defined classes into the IS A hierarchy, and checking the consistency of the ....

Illamarendi, A., Blanco, J. and A.Goni, "A uniform approach to design a federated system using BACK", Proc. Terminological Logic Users Workshop, Berlin, December 1991.

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Illarramendi, A., Blanco, J. M., and Goni, A., "A uniform approach to design a federated system using back," Proc. Terminological Logic Users Workshop, KIT--Report 95, Technische Universitat Berlin, Berlin, October, 1991, pp. 61--85.

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