MMI Paper on Semantic Mediation

Architectural OverviewThis paper serves as a basic introduction to semantic tools and mediation, an overview of MMI's semantic framework and tools, and a great citation for the MMI ORR work that has been funded by NSF and supported by MMI's staff and many volunteers.

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Architectural Overview The MMI Project is pleased to report an MMI-originated paper, Semantic mediation of vocabularies for ocean observing systems, has been published in the journal Computers & Geosciences. Co-authored by John Graybeal, Anthony Isenor, and Carlos Rueda, the paper describes why semantic mediation of vocabularies is needed for any diverse ocean observing system, and outlines the semantic framework and technologies introduced by MMI. It includes an explanation of the MMI Ontology Registry and Repository, describing many of its features, present uses, and possible future uses.

Please obtain the published source material at, or contact one of the authors (listed below) if you need a copy for your personal research.

Paper Summary


The collective terminology used in a community of interest identifies the important concepts used by that community. These concepts are related to the research activities of the community and therefore to the types of data that the community creates and uses. Such data may be obtained through direct measurement, through laboratory analysis, or through the numerical or physical modeling conducted by community members. The terminology associated with the data, collectively referred to as a vocabulary, often develops within subgroups of a larger community. When these subgroups are brought together, the disjointed nature of the vocabularies must be addressed for the data to be consolidated into a single, consistent data resource. This consolidation represents a critical challenge for the construction of an ocean observing system. The work presented here describes a semantic mediation framework, which is used to relate multiple oceanographic vocabularies, thereby allowing data consolidation. The framework is described in terms of capabilities required to manage the diverse vocabularies from the organizations that support an ocean observing system. The framework implementation then illustrates the required semantic mediation between the oceanographic vocabularies of the smaller communities, allowing an ocean observing system to appear as a coherent single system, producing coherent data resources from the originally disjoint systems.


► Semantic mediation of vocabularies is needed for any diverse ocean observing system. ► Providing community vocabulary services increases interoperability and open access. ► The MMI Ontology Registry and Repository is an existing service provider for the oceanographic community. ► Communal vocabulary creation and mapping increases sharing and synergy opportunities. ► Marine and environmental sciences will see increasing adoption of semantic services.

Keywords: Ontology; Marine; Metadata; Semantic; Interoperability

Article Outline

  1. Introduction: the problem with data terminology
  2. Definitions and requirements
    1. Definitions
    2. Requirements of the semantic framework, semantic manager, and semantic mediator layers
  3. Technologies and strategies
    1. Uniform Resource Identifier
    2. Ontologies
    3. Queries and reasoning
  4. Components of the semantic framework
    1. Data provider
    2. Semantic provider and semantic manager layers
    3. Semantic mediator
    4. Data user
  5. Sequence of operations
  6. Applications and implications of the semantic framework
    1. The marine community
    2. The system-of-systems
  7. Concluding remarks


  • John Graybeal, Monterey Bay Aquarium Research Institute (now University of California, San Diego)
  • Anthony Isenor, Defence Research and Development Canada
  • Carlos Rueda, Monterey Bay Aquarium Research Institute