ОНТОЛОГИИ - комментарии и определения

Определения

Русские руководства по онтологиям


Статьи энциклопедий
Онтология
Онтология , греч., учение о сущем; рассматривает самые общие определения, свойства и условия действительного бытия; первая часть метафизики; наз. Кантом трансцендентальной философией.- Онтологич. Новый Диск
Онтология (от греч. on, род. падеж ontos - сущее и ...логия ), раздел философии, в котором рассматриваются всеобщие основы, принципы бытия , его структура и закономерности. По своему существу О. выражает Рубрикон
ОНТОЛОГИЯ ОНТОЛОГИЯ греч. ученье о существе или о сущности, бытии, сути. Рубрикон

WHAT IS ONTOLOGY?


An ontology defines the terms used to describe and represent an area of knowledge. Ontologies are used by people, databases, and applications that need to share domain information (a domain is just a specific subject area or area of knowledge, like medicine, tool manufacturing, real estate, automobile repair, financial management, etc.). Ontologies include computer-usable definitions of basic concepts in the domain and the relationships among them (note that here and throughout this document, definition is not used in the technical sense understood by logicians). They encode knowledge in a domain and also knowledge that spans domains. In this way, they make that knowledge reusable.

The word ontology has been used to describe artifacts with different degrees of structure. These range from simple taxonomies (such as the Yahoo hierarchy), to metadata schemes (such as the Dublin Core), to logical theories. The Semantic Web needs ontologies with a significant degree of structure. These need to specify descriptions for the following kinds of concepts:

Classes (general things) in the many domains of interest
The relationships that can exist among things
The properties (or attributes) those things may have
Ontologies are usually expressed in a logic-based language, so that detailed, accurate, consistent, sound, and meaningful distinctions can be made among the classes, properties, and relations. Some ontology tools can perform automated reasoning using the ontologies, and thus provide advanced services to intelligent applications such as: conceptual/semantic search and retrieval, software agents, decision support, speech and natural language understanding, knowledge management, intelligent databases, and electronic commerce.

Ontologies figure prominently in the emerging Semantic Web as a way of representing the semantics of documents and enabling the semantics to be used by web applications and intelligent agents. Ontologies can prove very useful for a community as a way of structuring and defining the meaning of the metadata terms that are currently being collected and standardized. Using ontologies, tomorrow's applications can be "intelligent", in the sense that they can more accurately work at the human conceptual level.

Ontologies are critical for applications that want to search across or merge information from diverse communities. Although XML DTDs and XML Schemas are sufficient for exchanging data between parties who have agreed to definitions beforehand, their lack of semantics prevent machines from reliably performing this task given new XML vocabularies. The same term may be used with (sometimes subtle) different meaning in different contexts, and different terms may be used for items that have the same meaning. RDF and RDF Schema begin to approach this problem by allowing simple semantics to be associated with terms. With RDF Schema, one can define classes that may have multiple subclasses and super classes, and can define properties, which may have sub properties, domains, and ranges. In this sense, RDF Schema is a simple ontology language. However, in order to achieve interoperation between numerous, autonomously developed and managed schemas, richer semantics are needed. For example, RDF Schema cannot specify that the Person and Car classes are disjoint, or that a string quartet has exactly four musicians as members.

What I meant however was an ontology in the sense of the classic Gruber definition -- a specification of a conceptualization. In other words, what is the shared conceptualization of two trading partners as they plan their trading activities, identify each other in a market, negotiate their terms of trade, actualize their
their economic exchanges, and deal with their post actualization exceptions (I am using the ISO Open-edi phases here) ? In my mind, an ontologically-oriented team would feel incomplete if they had to walk away knowing that a significant component of this knowledge was left unspecified in their efforts (for example, "where approximately are we in this deal?"). Much of it was certainly embedded in the paper documents of years past, but simply stopping there would be (again in my mind) an incomplete effort no matter how exhaustive their levels of effort were at unearthing document-bound knowledge.

Not an operational defintion perhaps, but explained
better I hope.

Bill McCarthy

This process of making objects out of sentences and other entities is called reification. It is necessary for expressive power but again leads to complications in reasoning. It is discussed in (McCarthy 1979).