Conceptual Modeling with DL Ehsan Pourmand 1192020 Conceptual

Conceptual Modeling with DL Ehsan Pourmand 11/9/2020 Conceptual Modeling with DL

Agenda l l l Quick Overview of Modeling Elementary DL Modeling Individuals & concepts in DL Materialization & Part-whole relationships Conceptual Modeling Methodology 11/9/2020 Conceptual Modeling with DL

Quick Overview of Modeling l l l Universe of Discourse (Uof. D) Abstracting away irrelevant details of the Uof. D Efficient states examination of the Uof. D Conceptual models offer expressive facilities for modeling applications directly and naturally including semantic terms Conceptual models Application – Artificial Intelligence Programs – DB Conceptual level Schema – All OO programs 11/9/2020 Conceptual Modeling with DL

Benefits of Conceptual Modeling It results in a structured information model, which is easier to build and maintain. l DLs further this goal : by supporting the automatic classification of concepts with respect to others, thereby revealing generalizations that may not have been recognized by the modeler l 11/9/2020 Conceptual Modeling with DL

Elementary DL Modeling l l l DL: object-centered view of the world Binary relationships are modeled directly in DLs using roles and attributes Converse relationships should capture in model Use natural language name that is asymmetric R(a, b) should be read as “a R b” – lent. To(BOOK 23, GIANNI); lent. To(GIANNI, BOOK 23) – loan(GIANNI, BOOK 23); loan(BOOK 23, GIANNI) 11/9/2020 Conceptual Modeling with DL

Fundamental DL Property support for the distinction between primitive/atomic concepts and defined concepts l Example: Borrower ⊑ (all has. Borrowed Book) Borrower ≡ (and (all has. Borrowed Book) (at-least 1 has. Borrowed)) l 11/9/2020 Conceptual Modeling with DL

Individuals in the World what constitutes a relevant individual in a Uof. D depends very much on what we want to do with the information. l A general heuristic is that if we expect certain notions to be counted, then they must be modeled as individuals. l Another heuristic is that notions that do not have an inception time are usually modeled as concepts l 11/9/2020 Conceptual Modeling with DL

Values vs. Objects l l l l Many DLs only support reasoning with objects Composite values such as dates need to be modeled as objects with attributes They are treated as distinct for the purposes of counting and identity checking Resulting in reasoning anomalies Implemented DLs such as Classic support values from the underlying programming language Others, such as ALC(D) and SHOQ(D) allow attributes to have values from so-called “concrete domains, ” concrete domains are required to have their own, independent reasoners, which are then coupled with the DL reasoner. only the highly expressive DLR languages support notions such as n-tuples and recursive fixed-point structures, from which one can build lists, trees, 11/9/2020 Conceptual Modeling with DL

Individuals vs. references to them we usually want objects to remain related, even if names are changed l General Rule: one should always deal with the individual objects l in some cases one wants to state relationships between intensional references l • head. Of(GIANNI, COMMITTEE 3) • head. Of(director. Of(NBULIBRARY), COMMITTEE 3). 11/9/2020 Conceptual Modeling with DL

Essential vs. incidental concepts l /* Option 1 — being hardcover is part of the definition */ Book. On. Loan ≡ (and Book (at-least 1 lent. To) (fills binding 'hardcover)) l /* Option 2 — being hardcover is an additional necessary condition */ Book. On. Loan ≡ (and Book (at-least 1 lent. To)) Book. On. Loan ⊑ (fills binding 'hardcover) l This distinction is also important if we consider the task of classifying concepts into a taxonomy 11/9/2020 Conceptual Modeling with DL

Reified concepts and meta-roles l No support for meta-roles in DL l Solution: Creating a separate Meta-individual 11/9/2020 Conceptual Modeling with DL

Dynamics of concept membership l When changes in the model are allowed l Rigid roles vs. transient roles l Transient property can be a subconcept of rigid one l No support in standard DL 11/9/2020 Conceptual Modeling with DL

Materialization Relation between a general notion & 0 -N more specific notion l Modeling separate individual instance? l Use predefined Materialization. Of role l It is not fully supported yet l 11/9/2020 Conceptual Modeling with DL

Part-whole aggregation l Three kinds of wholes: – Complexes (components) – Collections (members) – Masses (quantities) l Two aspect of relationship between parts & wholes: – Existence – Properties l Use has. DComponent, … relationship 11/9/2020 Conceptual Modeling with DL

Constraints & Views l No Support for Constraint in standard DL l Concept Constructors in extended DL l test date-after (due. Date lent. On) l Various views of information is needed l Material. On. Loan , Material. In. Library 11/9/2020 Conceptual Modeling with DL

Conceptual Modeling Methodology l Identify the individuals one can encounter in the Uof. D. Revisit this later considering issues such as materialization and values. l Enumerate concepts that group these values. l Distinguish independent concepts from relationship-roles. 11/9/2020 Conceptual Modeling with DL

Conceptual Modeling Methodology Develop a taxonomy of concepts. Revisit this later considering issues such as disjointness and covering for subconcepts. l Systematically search for part-whole relationships between objects, creating roles for them. l Identify other ‘properties’ of objects, and then general relationships in which objects participate. l 11/9/2020 Conceptual Modeling with DL

Conceptual Modeling Methodology l Determine local constraints involving roles such as cardinality limits and value restrictions. l Determine more general constraints on relationships, such as those that can be modelled by subroles or same-as. 11/9/2020 Conceptual Modeling with DL

Conceptual Modeling Methodology l Distinguish essential from incidental properties of concepts, as well as primitive from defined concepts. l Consider properties of concepts such as rigidity, identifiers, etc. , and use the techniques to simplify and realign the taxonomy of primitive concepts 11/9/2020 Conceptual Modeling with DL

Conclusion l DL Strenghth – Primitive and defined concepts – Concept specification – Treatment of roles l DL Weakness – Dynamic aspect of domains – Materialization – Meta-information l Biggest Problem: testing for correctness & completeness 11/9/2020 Conceptual Modeling with DL

Thanks for your attention! l Question? 11/9/2020 Conceptual Modeling with DL