29,032 research outputs found
Evaluating Knowledge Representation and Reasoning Capabilites of Ontology Specification Languages
The interchange of ontologies across the World Wide Web (WWW) and the cooperation among heterogeneous agents placed on it is the main reason for the development of a new set of ontology specification languages, based on new web standards such as XML or RDF. These languages (SHOE, XOL, RDF, OIL, etc) aim to represent the knowledge contained in an ontology in a simple and human-readable way, as well as allow for the interchange of ontologies across the web. In this paper, we establish a common framework to compare the expressiveness of "traditional" ontology languages (Ontolingua, OKBC, OCML, FLogic, LOOM) and "web-based" ontology languages. As a result of this study, we conclude that different needs in KR and reasoning may exist in the building of an ontology-based application, and these needs must be evaluated in order to choose the most suitable ontology language(s)
Query inseparability by games
We investigate conjunctive query inseparability of description logic knowledge bases (KBs) with respect to a given signature, a fundamental problem for KB versioning, module extraction, forgetting and knowledge exchange. We develop a game-theoretic technique for checking query inseparability of KBs expressed in fragments of Horn-ALCHI, and show a number of complexity results ranging from P to ExpTime and 2ExpTime. We also employ our results to resolve two major open problems for OWL 2 QL by showing that TBox query inseparability and the membership problem for universal UCQ-solutions in knowledge exchange are both ExpTime-complete for combined complexity
Research Strategies: Bibliographic Instruction for Undergraduates
published or submitted for publicatio
A knowledge-based approach to VLSI-design in an open CAD-environment
A knowledge-based approach is suggested to assist a designer in the increasingly complex task of generating VLSI-chips from abstract, high-level specifications of the system. The complexity of designing VLSI-circuits has reached a level where computer-based assistance has become indispensable. Not all of the design tasks allow for algorithmic solutions. AI technique can be used, in order to support the designer with computer-aided tools for tasks not suited for algorithmic approaches. The approach described in this paper is based upon the underlying characteristics of VLSI design processes in general, comprising all stages of the design. A universal model is presented, accompanied with a recording method for the acquisition of design knowledge - strategic and task-specific - in terms of the design actions involved and their effects on the design itself. This method is illustrated by a simple design example: the implementation of the logical EXOR-component. Finally suggestions are made for obtaining a universally usable architecture of a knowledge-based system for VLSI-design
Conjunctive query inseparability in OWL2QL is ExpTime-hard
We settle an open question on the complexity of the following problem: given two OWL2QL TBoxes and a signature, decide whether these TBoxes return the same answers to any conjunctive query over any data formulated in the given signature. It has been known that the complexity of this problem is between PSpace and ExpTime. Here we show that the problem is ExpTime-complete and, in fact, deciding whether two OWL2QL knowledge bases (each with its own data) give the same answers to any conjunctive query is ExpTime-hard
Semantic Technologies for Manuscript Descriptions — Concepts and Visions
The contribution at hand relates recent developments in the area of the World Wide
Web to codicological research. In the last number of years, an informational extension
of the internet has been discussed and extensively researched: the Semantic Web. It
has already been applied in many areas, including digital information processing of
cultural heritage data. The Semantic Web facilitates the organisation and linking of
data across websites, according to a given semantic structure. Software can then process
this structural and semantic information to extract further knowledge. In the area
of codicological research, many institutions are making efforts to improve the online
availability of handwritten codices. If these resources could also employ Semantic
Web techniques, considerable research potential could be unleashed. However, data
acquisition from less structured data sources will be problematic. In particular, data
stemming from unstructured sources needs to be made accessible to SemanticWeb tools
through information extraction techniques. In the area of museum research, the CIDOC
Conceptual Reference Model (CRM) has been widely examined and is being adopted
successfully. The CRM translates well to Semantic Web research, and its concentration
on contextualization of objects could support approaches in codicological research.
Further concepts for the creation and management of bibliographic coherences and
structured vocabularies related to the CRM will be considered in this chapter. Finally, a
user scenario showing all processing steps in their context will be elaborated on
Mill on logic
Working within the broad lines of general consensus that mark out the core features of John Stuart Mill’s (1806–1873) logic, as set forth in his A System of Logic (1843–1872), this chapter provides an introduction to Mill’s logical theory by reviewing his position on the relationship between induction and deduction, and the role of general premises and principles in reasoning. Locating induction, understood as a kind of analogical reasoning from particulars to particulars, as the basic form of inference that is both free-standing and the sole load-bearing structure in Mill’s logic, the foundations of Mill’s logical system are briefly inspected. Several naturalistic features are identified, including its subject matter, human reasoning, its empiricism, which requires that only particular, experiential claims can function as basic reasons, and its ultimate foundations in ‘spontaneous’ inference. The chapter concludes by comparing Mill’s naturalized logic to Russell’s (1907) regressive method for identifying the premises of mathematics
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