DCMI Abstract Model Analysis Resource Model Jorge Morato– Information Ingeneering Universidad Carlos III de Madrid

INTRODUCTION DCAM: What is: an abstract model for metadata schemes (scheme validation, concept interoperability and understanding). It is a recommendation Importance: Universal metadata scheme model reference.

MOTIVATION Importance of DCAM To make easy its understanding To contribute with our experience in UML Review DCAM concepts improving notation and representation to facilitate their interpretation

OBJECTIVES To review the graphic model representation from a 1.5 UML point of view [j ust resource model due to extension reasons ] To adecuate the graphic representation to UML standard, using a CASE modelling tool [umlCAKE] Analyze abstract resource model concepts -> Propose alternative representations and revised textual definitions.

Resource Model. Aspect 1 Textual definition in DCAM ''Each resource may be a member of one or more classes'' 0..n means zero or more classes The graph means: a class could be part of a resource

Resource Model. Proposal 1 Textual definition as the right one (“each resource may be a member of 1..n classes…”). The contrary, not in text, could be true Minimum multiplicity is set to zero. A resource may not belong to any class (gloss. “a resource is something that have an identity”) Other aspects: [gloss.] a resource can include “a collection of other resources” resource 0..* class resource

Resource Model. Aspect 2 and proposal Multiplicity is not specified Property/value is used to describe a resource, thus: An instance of property/value belongs only to one resource, and have sense only if this resource exists, therefore it is not an aggregation but a composition *

Resource Model. Aspect 3 and proposal Multiplicity is completed Checking composition: - Instances of value and property have not sense without property/value - Value or property belongs only to one property/value pair  Composition 1..1 {and} To clarify, a constraint may be defined between the relationships (it is not necessary with 1 as minimum)

Resource Model. Proposal 4 In Metadata world, semantics may be shared (ie. from an ontology) or defined locally The local semantics may include concepts defined externally Note that semantics is an abstract class To be part of the scheme a shared semantic should be associated to an instance of local semantics Semantic overlapping among should be avoided This solution improve interoperability even with applications unable to interpret the proportioned semantic from a shared resource

Resource Model. Proposal 4 We analyzed aggregation/composition, taken into account the previous approach

Resource Model. Aspect 5 In generalization child classes inherit attributes, operations and associations declared in the parent class. Specialization is obtained by defining a subclass So the association class “refines class semantics” it is not necessary because has the same meaning than the generalization relationship

Resource Model. Proposal 5 Class has a local semantics Subclass by means of specialization inherits its own local semantics The same solution may be applied to property semantics

UML Notation Aspects In UML to express zero or more is employed “0..*” in the DCAM is used the E/R notation “0..n” To differentiate classes for other elements the first letter may be in capitals Every association may be named in order to facilitate model understanding Resource Atribute/Value Pair Value Property Semantics Class Shared Semantics Subclass Subproperty Local Semantics 0..* * * 1..1 {complete}

Conclusions Facilitate the interpretation and use of the DCMI abstract model, presenting it with a formal notation and making clear those concepts susceptible to revision in relation to its definition and representation. Next steps: though it has not been included for extension reasons, the analysis of the description model, also included in the DCMI abstract model, is being developed.

DCMI Abstract Model Analysis Resource Model Jorge Morato– Information Ingeneering Universidad Carlos III de Madrid

REFERENCES DCMI (Dublin Core Metadata Initiative). DCMI Abstract Model Disponible en OMG (Object Managment Group). Unified Modeling Language, version 1.5. Disponible en Reuse Company. umlCAKE: Herramienta CASE de modelado con UML Disponible en