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44
Logical foundations of object-oriented and frame-based languages
- JOURNAL OF THE ACM
, 1995
"... We propose a novel formalism, called Frame Logic (abbr., F-logic), that accounts in a clean and declarative fashion for most of the structural aspects of object-oriented and frame-based languages. These features include object identity, complex objects, inheritance, polymorphic types, query methods, ..."
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Cited by 876 (65 self)
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We propose a novel formalism, called Frame Logic (abbr., F-logic), that accounts in a clean and declarative fashion for most of the structural aspects of object-oriented and frame-based languages. These features include object identity, complex objects, inheritance, polymorphic types, query methods, encapsulation, and others. In a sense, F-logic stands in the same relationship to the objectoriented paradigm as classical predicate calculus stands to relational programming. F-logic has a model-theoretic semantics and a sound and complete resolution-based proof theory. A small number of fundamental concepts that come from object-oriented programming have direct representation in F-logic; other, secondary aspects of this paradigm are easily modeled as well. The paper also discusses semantic issues pertaining to programming with a deductive object-oriented language based on a subset of F-logic.
Managing Semistructured Data With Florid: A Deductive Object-Oriented Perspective
, 1998
"... The closely related research areas management of semistructured data and languages for querying the Web have recently attracted a lot of interest. We argue that languages supporting deduction and object-orientation (dood languages) are particularly suited in this context: Object-orientation provid ..."
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Cited by 75 (21 self)
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The closely related research areas management of semistructured data and languages for querying the Web have recently attracted a lot of interest. We argue that languages supporting deduction and object-orientation (dood languages) are particularly suited in this context: Object-orientation provides a flexible common data model for combining information from heterogeneous sources and for handling partial information. Techniques for navigating in object-oriented databases can be applied to semistructured databases as well, since the latter may be viewed as (very simple) instances of the former. Deductive rules provide a powerful framework for expressing complex queries in a high-level, declarative programming style. We elaborate
FLORA-2: A Rule-Based Knowledge Representation and Inference Infrastructure for the Semantic Web
- In Second International Conference on Ontologies, Databases and Applications of Semantics (ODBASE
, 2003
"... Abstract. Flora-2 is a rule-based object-oriented knowledge base system designed for a variety of automated tasks on the Semantic Web, ranging from meta-data management to information integration to intelligent agents. The Flora-2 system integrates F-logic, HiLog, and Transaction Logic into a cohere ..."
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Cited by 66 (5 self)
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Abstract. Flora-2 is a rule-based object-oriented knowledge base system designed for a variety of automated tasks on the Semantic Web, ranging from meta-data management to information integration to intelligent agents. The Flora-2 system integrates F-logic, HiLog, and Transaction Logic into a coherent knowledge representation and inference language. The result is a flexible and natural framework that combines rule-based and object-oriented paradigms. This paper discusses the principles underlying the design of the Flora-2 system and describes its salient features, including meta-programming, reification, logical database updates, encapsulation, and support for dynamic modules. 1
Web and Semantic Web Query Languages: A Survey
"... A number of techniques have been developed to facilitate powerful data retrieval on the Web and Semantic Web. Three categories of Web query languages can be distinguished, according to the format of the data they can retrieve: XML, RDF and Topic Maps. This ar-ticle introduces the spectrum of langu ..."
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Cited by 47 (21 self)
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A number of techniques have been developed to facilitate powerful data retrieval on the Web and Semantic Web. Three categories of Web query languages can be distinguished, according to the format of the data they can retrieve: XML, RDF and Topic Maps. This ar-ticle introduces the spectrum of languages falling into these categories and summarises their salient aspects. The languages are introduced us-ing common sample data and query types. Key aspects of the query languages considered are stressed in a conclusion.
Calibrating the query optimizer cost model of IRO-DB, an object-oriented federated database system
- In Proc. of the Conf. on Very Large Data Bases (VLDB
, 1996
"... IRO-DB is an object-oriented federated database system to access multiple data sources from an ODMG compliant C++ inteqace. The system encompasses several components, including local database adapters to homogenize local data sources, a remote object access component to query and transfer collection ..."
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Cited by 33 (2 self)
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IRO-DB is an object-oriented federated database system to access multiple data sources from an ODMG compliant C++ inteqace. The system encompasses several components, including local database adapters to homogenize local data sources, a remote object access component to query and transfer collections of objects from site to site, ana ’ a mediator to de$ne integrated views, decompose ana’ optimize queries, and combine results. This paper gives an overview of the IRO-DB architecture and describes in detail the cost evaluator currently under elaboration for the next version of the distributed query optimizer. The cost model is composed of a set of mathematical formulas with coejficients to estimate the cost of the search operators. The coeficients are deduced from a calibrating objectoriented database composed of linked collections of objects. A tuning application is run on each local site to adjust the cost formulas and fix the coeficients. We report on the tuning of 02 and ObjectStore. We show that the estimation is quite accurate for path traversals with the 007 benchmark on top of ObjectStore. 1.
FLORID - A Prototype for F-Logic
- In Proc. Intl. Conference on Data Engineering
, 1997
"... this paper we present FLORID ..."
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On a Declarative Semantics for Web Queries
, 1997
"... With the increasing importance of the World Wide Web as an information source, there is a growing interest for integration of Web and database technology. Several Web query languages have been presented to overcome the shortcomings of conventional search engines, most of them lacking a formal semant ..."
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Cited by 20 (5 self)
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With the increasing importance of the World Wide Web as an information source, there is a growing interest for integration of Web and database technology. Several Web query languages have been presented to overcome the shortcomings of conventional search engines, most of them lacking a formal semantics. In this paper, we propose F-logic as a means to explore, query and restructure Web information, and to integrate it with a local database. Two major advantages of this approach are its declarative semantics, based on the semantics of F-logic, and the rich modeling capabilities which make F-logic particularly suitable to handle heterogeneous data. The presented semantics directly yields a bottom-up evaluation algorithm that can be easily incorporated into the existing F-logic prototype Florid.
RDF querying: Language constructs and evaluation methods compared
- IN: REASONING WEB, SECOND INTERNATIONAL SUMMER SCHOOL 2006. VOLUME 4126 OF LNCS.
, 2006
"... This article is firstly an introduction into query languages for the Semantic Web, secondly an in-depth comparison of the languages introduced. Only RDF query languages are considered because, as of the writing of this paper, query languages for other Semantic Web data modeling formalisms, especial ..."
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Cited by 16 (5 self)
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This article is firstly an introduction into query languages for the Semantic Web, secondly an in-depth comparison of the languages introduced. Only RDF query languages are considered because, as of the writing of this paper, query languages for other Semantic Web data modeling formalisms, especially OWL, are still an open research issue, and only a very small number of, furthermore incomplete, proposals for querying Semantic Web data modeled after other formalisms than RDF exist. The limitation to a few RDF query languages is motivated both by the objective of an in-depth comparison of the languages addressed and by space limitations. During the three years before the writing of this article, more than three dozen proposals for RDF query languages have been published! Not only such a large number, but also the often immature nature of the proposals makes the focus on few, but representative languages a necessary condition for a non-trivial comparison. For this article, the following RDF query languages have been, admittedly subjectively, selected: Firstly, the “relational” or “pattern-based” query languages SPARQL, RQL, TRIPLE, and Xcerpt; secondly the reactive rule query language Algae; thirdly and last the “navigational access ” query language Versa. Although subjective, this choice is arguably a good coverage of the diverse language paradigms considered for querying RDF data. It is the authors ’ hope and expectation, that this comparison will motivate and trigger further similar studies, thus
Survey over Existing Query and Transformation Languages -- Revision 2.0
, 2006
"... A widely acknowledged obstacle for realizing the vision of the Semantic Web is the inability of many current Semantic Web approaches to cope with data available in such diverging representation formalisms as XML, RDF, or Topic Maps. A common query language is the first step to allow transparent acce ..."
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Cited by 12 (5 self)
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A widely acknowledged obstacle for realizing the vision of the Semantic Web is the inability of many current Semantic Web approaches to cope with data available in such diverging representation formalisms as XML, RDF, or Topic Maps. A common query language is the first step to allow transparent access to data in any of these formats. To further the understanding of the requirements and approaches proposed for query languages in the conventional as well as the Semantic Web, this report surveys a large number of query languages for accessing XML, RDF, or Topic Maps. This is the first systematic survey to consider query languages from all these areas. From the detailed survey of these query languages, a common classification scheme is derived that is useful for understanding and differentiating languages within and among all three areas. This revision of deliverable I4-D1 extends that deliverable by a refined version of the presented material that has been published as a chapter in the LNCS tutorial volume for the REWERSE “Reasoning Web ” 2005 summer school as well as short outlooks on further refinements of the material for upcoming tutorials
