KWTR: description logics

[edit] Contributors:

Jos de Bruijn, FUB

Please add your CV in the list of contributors

Description Logics are a family of class-based Knowledge Representation formalisms, which are subsets of first-order logic. The Lite and DL species of OWL are based on Description Logics.

• 1. CURRENT TRENDS IN SEMANTIC WEB (In the following part we intend to identify the state of the art of Semantic Web based theories, methods, applications and tools in your research field.)

• • 1.1. One or more examples (case studies) in which semantic web has been used.

  Name of the institutions:
  Industry / sector: 
  Business activities improved by the SW solutions: 
  Research Needs: 
  Name of the project:
  Tools and applications implemented in the project:

• • 1.2. The first 4 Semantic Web based tools used in your research fields.

Name: Racer
Website: http://www.racer-systems.com/
Main characteristics:  Tableaux-based Description Logic reasoner, with optimizations for instance retrieval.
Open problems: treatment of nominals is not complete; assumes uniqueness of names

Name: FaCT++
Website: http://owl.man.ac.uk/factplusplus/
Main characteristics:  Tableaux-based Description Logic reasoner; support the SROIQ description 
 logic, which underlies the OWL 1.1 proposal.
Open problems: 

Name: iCOM
Website: http://www.racer-systems.com/
Main characteristics:  Tool for conceptual (ontology) modeling, with DL reasoning support for 
 detecting inconsistencies and finding implicit information.
Open problems: 

• • 1.3. A short summary of the first 3 best papers in the field.

Reference: Franz Baader, Diego Calvanese, Deborah L. McGuinness, Daniele Nardi,
 and Peter F. Patel-Schneider, editors. The Description Logic Handbook.
 Cambridge University Press, 2003.
Short abstract: Description Logics are a family of knowledge representation languages that have been studied extensively
  in Artificial Intelligence over the last two decades. They are embodied in several knowledge-based systems and are used to 
 develop various real-life applications. The Description Logic Handbook provides a thorough account of the subject, covering all
aspects of research in this field, namely: theory, implementation, and applications. Its appeal will be broad, ranging from 
 more theoretically-oriented readers, to those with more practically-oriented interests who need a sound and modern 
 understanding of knowledge representation systems based on Description Logics. The chapters are written by some of the most 
 prominent researchers in the field, introducing the basic technical material before taking the reader to the current state of 
 the subject, and including comprehensive guides to the literature. In sum, the book will serve as a unique reference for the 
 subject, and can also be used for self-study or in conjunction with Knowledge Representation and Artificial Intelligence 
 courses.

Reference:  Ian Horrocks and Peter Patel-Schneider. Reducing OWL entailment to
 description logic satisfiability. Journal of Web Semantics, 1(4):345–357, 2004.
Short abstract: The paper shows how to reduce ontology entailment for the OWL DL and OWL Lite ontology languages to 
 knowledge base satisfiability in (respectively) the Click to view the MathML source and Click to view the MathML source 
 description logics. This is done by first establishing a correspondence between OWL ontologies and description logic 
 knowledge bases and then by showing how knowledge base entailment can be reduced to knowledge base satisfiability.

Reference: Diego Calvanese, De Giacomo, Giuseppe, Domenico Lembo, Maurizio Lenzerini and Riccardo Rosati. Tractable 
 Reasoning and Efficient Query Answering in Description Logics:  The DL-Lite Family
Short abstract: The paper proposes a new family of Description Logics, called DL-Lite, specifically tailored to capture 
 basic ontology languages, while keeping low complexity of reasoning. Reasoning here means not only computing subsumption 
 between concepts, and checking satisfiability of the whole knowledge base, but also answering complex queries (in particular,
 unions of conjunctive queries) over the instance level of the DL knowledge base. We show that, for the Description Logics of 
 the DL-Lite family, the usual DL reasoning tasks are polynomial in the size of the TBox, and query answering is LOGSPACE in 
 the size of the ABox (i.e., in data complexity). To the best of our knowledge, this is the first result of polynomial time 
 data complexity for query answering over Description Logic knowledge bases. A notable feature of our logic is to allow for a 
 separation between TBox and ABox reasoning during query evaluation: the part of the process requiring TBox reasoning is 
 independent of the ABox, and the part of the process requiring access to the ABox can be carried out by an SQL engine, thus 
 taking advantage of the query optimization strategies provided by current Data Base Management Systems. Since it can be shown
  that even slight extensions to the logics of the DL-Lite family make query answering at least NLOGSPACE in data complexity, 
 thus ruling out the possibility of using on-the-shelf relational technology for query processing, we can conclude that the 
 logics of the DL-Lite family are the maximal Description Logics supporting efficient query answering over large amounts of 
 instances.

• • 1.4. A short list of open problems in theories and methods.

These problems are currently being investigated:

- efficient query answering with large sets of data
- combining Description Logics with rules
- definition and investigation of Description Logics for which reasoning is tractable

• 2. TRENDS ON THEORIES AND METHODS, SERVICES AND APPLICATIONS

• • 2.1. Research projects in which contributors are involved, along with a general description. Moreover, suggest for each project the possible future uses and applications related to the Semantic Web, the acceptance and diffusion in each period considered, the benefits, and the problems that will be probably occur.

Name of the project: 
Type: 
Duration: 
Partners: 
Research Institution: 
Industrial Partners: 
Core activities: 
Market opportunities: 
Problems and missing tools: 
Problems – Semantic Web culture is missing: 

• • 2.2. Some topics that will not be solved in short and medium term, for each of them there is a short explanation of the main reasons and (if possible) some references.

Topics: 
Reason: 
References: none

• 3. TRENDS ON TOOLS
  • 3.1. A list of the most relevant semantic based demos in the area.

Name: 
Website: 
Description: see the web page 
References: 
Main features:
Open problems:

• • 3.2. A short description of tools that are still missing. A description of business activities and problems they should solve, will be provided.

• 4.Please fell free to add any comment or suggestion.