953 resultados para metadata schemes


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In this paper a flexible approach to design LMS with QTI Ready component based on the e-Learning standards AICC and IMS QTI is described. This system and component permits a dynamic learning and assessment process. QTI Ready component can provide these facilities to other real world virtual learning management system.

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The U.S. National Science Foundation metadata registry under development for the National Science Digital Library (NSDL) is a repertory intended to manage both metadata schemes and schemas. The focus of this draft discussion paper is on the scheme side of the development work. In particular, the concern of the discussion paper is with issues around the creation of historical snapshots of concept changes and their encoding in SKOS. Through framing the problem as we see it, we hope to find an optimal solution to our need for a SKOS encoding of these snapshots. Since what we are seeking to model is concept change, it is necessary at the outset to make it clear that we are not talking about changes to a concept of such a nature that would require the declaration a new concept with its own URI.In the project, we avoid the use of the terms “version” and “versioning” with regard to changes in concepts and reserve their use to the significant changes of schemes as a whole. Significant changes triggering a new scheme version might include changes in scheme documentation that express a significant shift in the purpose, use or architecture of the scheme. We use the term “snapshot” to denote the state of a scheme at identifiable points in time. Thus, snapshots are identifiable views of a scheme that record the incremental changes that have occurred to concepts, relationships among concepts, and scheme documentation since the last snapshot. Aspects of concept change occur that we need to capture and make available both through the registry and through potentially in transmission of a scheme to other registries. We call these capturings “concept instances.”

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In this article, we describe the development of an exten- sion to the Simple Knowledge Organization System (SKOS) to accommodate the needs of vocabulary devel- opment applications (VDA) managing metadata schemes and requiring close tracking of change to both those schemes and their member concepts. We take a neo- pragmatic epistemic stance in asserting the need for an entity in SKOS modeling to mediate between the abstract concept and the concrete scheme. While the SKOS model sufficiently describes entities for modeling the current state of a scheme in support of indexing and search on the Semantic Web, it lacks the expressive power to serve the needs of VDA needing to maintain scheme historical continuity. We demonstrate prelimi- narily that conceptualizations drawn from empirical work in modeling entities in the bibliographic universe, such as works, texts, and exemplars, can provide the basis for SKOS extension in ways that support more rig- orous demands of capturing concept evolution in VDA.

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A description of a data item's provenance can be provided in dierent forms, and which form is best depends on the intended use of that description. Because of this, dierent communities have made quite distinct underlying assumptions in their models for electronically representing provenance. Approaches deriving from the library and archiving communities emphasise agreed vocabulary by which resources can be described and, in particular, assert their attribution (who created the resource, who modied it, where it was stored etc.) The primary purpose here is to provide intuitive metadata by which users can search for and index resources. In comparison, models for representing the results of scientific workflows have been developed with the assumption that each event or piece of intermediary data in a process' execution can and should be documented, to give a full account of the experiment undertaken. These occurrences are connected together by stating where one derived from, triggered, or otherwise caused another, and so form a causal graph. Mapping between the two approaches would be benecial in integrating systems and exploiting the strengths of each. In this paper, we specify such a mapping between Dublin Core and the Open Provenance Model. We further explain the technical issues to overcome and the rationale behind the approach, to allow the same method to apply in mapping similar schemes.

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A strong designated verifier signature scheme makes it possible for a signer to convince a designated verifier that she has signed a message in such a way that the designated verifier cannot transfer the signature to a third party, and no third party can even verify the validity of a designated verifier signature. We show that anyone who intercepts one signature can verify subsequent signatures in Zhang-Mao ID-based designated verifier signature scheme and Lal-Verma ID-based designated verifier proxy signature scheme. We propose a new and efficient ID-based designated verifier signature scheme that is strong and unforgeable. As a direct corollary, we also get a new efficient ID-based designated verifier proxy signature scheme.

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Anomalous dynamics in complex systems have gained much interest in recent years. In this paper, a two-dimensional anomalous subdiffusion equation (2D-ASDE) is considered. Two numerical methods for solving the 2D-ASDE are presented. Their stability, convergence and solvability are discussed. A new multivariate extrapolation is introduced to improve the accuracy. Finally, numerical examples are given to demonstrate the effectiveness of the schemes and confirm the theoretical analysis.