How can Computer Science contribute to

Research Publishing?

Introduction to KRR Group

Who are we?• Academics

– Ian Horrocks– A. N. Other

• Research Students– Héctor Pérez-Urbina– Rob Shearer

• Research Staff– Bernardo Cuenca Grau– Birte Glimm– Yevgeny Kazakov– Boris Motik– Rob Shearer

What Do We Do?

• Knowledge representation (obviously)

• Ontologies and ontology languages

• Description logics– Formal underpinnings of ontology languages

• Reasoning problems and algorithms

• Implementation and optimisation of reasoning systems

Relevance to Publishing?

Annotations• Key role will be played by annotations

Annotations• Key role will be played by annotations• But how can meaning be understood by software?

Now... that should clear up a few things around here

Annotation Semantics• Agree on meaning of a set of terms

• E.g., Dublin Core

– Limited flexibility and extensibility– Limited number of things can be expressed

• Agree on language used to define meanings• E.g., an ontology language

– Flexible and extensible– New terms can be formed by combining existing ones– Meaning (semantics) of such terms is formally specified

What is an Ontology?A model of (some aspect of) the world• Introduces vocabulary relevant to domain

– Often includes names for classes and relationships

• Specifies intended meaning of vocabulary– Typically formalised using a suitable logic

• Closely related to schemas in the DB world– Instantiated by set of individuals and relations– Defines constraints on possible instantiations

Supporting Ontology Engineering• Developing and maintaining quality ontolgies is very challenging

• Users need tools and services, e.g., to help check if ontology is:

– Meaningful — all named classes can have instances

Supporting Ontology Engineering• Developing and maintaining quality ontolgies is very challenging

• Users need tools and services, e.g., to help check if ontology is:

– Meaningful — all named classes can have instances

– Correct — captures intuitions of domain experts

Supporting Ontology Engineering• Developing and maintaining quality ontolgies is very challenging

• Users need tools and services, e.g., to help check if ontology is:

– Meaningful — all named classes can have instances

– Correct — captures intuitions of domain experts

– Minimally redundant — no unintended synonyms

Banana split Banana sundae

• Range of new “non-standard” services supporting, e.g.:– Error diagnosis and repair

Supporting Ontology Engineering

• Range of new “non-standard” services supporting, e.g.:– Error diagnosis and repair– Modular design and integration

• What is the effect of merging O2 into O1?

– Module Extraction• Extract a (small) module from O capturing all “relevant” information

about some vocabulary V

– Bottom-up design• Find a (small and specific) concept describing a set of individuals

Supporting Ontology Engineering

• In an Ontology based Information System (OIS),Query answering ¼ computing logical entailment– Reasoner needed in order to answer queries, e.g.:

• C is a sub-class of D iff O ² 8 x . C(x) ! D(x)• a is an instance of C iff O ² C(a)

OIS with no reasoner ¼ DBMS with no query engine

Supporting Query Answering

Information Integration• Ontologies provide unifying schema

– Bridging between different data sources

• Query answering w.r.t.ontology– Date retrieved from relevant sources

• Similar to data integration in DBs– More flexible– Deductive capabilities

Driving User Interfaces• Interface reflects structure of knowledge• Query by navigation• Semantically meaningful presentation of data

– Easier understanding

• Context aware

Research Themes

Ontology Languages• Standards crucial

– Interoperability – Tool support

• W3C OWL ontology language standard– Central role in development of OWL language– Leading development of OWL 2

• Extension to OWL driven by application requirements

• OWL 3?– Graphs– Integrity constraints– …

Scalability• Integration of DLs with DBs• Tractable ontology languages

– Lightweight languages for data-intensive applications– Reasoning can be reduced to SQL querying

• New HermiT DL reasoner– Implements optimised hypertableau algorithm– Already outperforms existing reasoners– Aim is to push the limits of “practical” reasoning

New Reasoning ServicesIntegration & extraction of modules• Algorithms and practical techniques• Incremental reasoning• Methodologies and tool support

New Reasoning Services• Conjunctive query answering• Views

– Definition and application in ontologies– Algorithms and tool support

• Information hiding and privacy– Lift/transform ideas from DB research– Reformulate as reasoning problems

Thank you for listening

Any questions?