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					Ontology (1)
On the Ontology of the translation and definition
- Ontology Ontology is the theory
- 1991/Neches such as: paper constitutes the basic terms of vocabulary and
relationships, and the use of these terms and relations constitute the extension of the
provisions of these terms the definition of the rules;
- 1993/Gruber: a clear conceptual model specification;
- 1997/Borst: shared conceptual model of formal specification;
- 1998/Studer: shared conceptual model of a clear formal specification
1998/Studer: shared conceptual model of a clear formal specification
l 1. Conceptual model (conceptualization)
- Abstract of the objective world by some phenomena (Phenomenon) are related
concepts and models, meaning that independent of their specific environmental
conditions
l 2. Clear (explicit)
- The use of the concept and use of these concepts have a clear definition of the
constraints
l 3. Formal (formal)
- Ontology is a computer-readable.
l 4. Sharing (share)
- Ontology is reflected in the common recognition of knowledge, and reflecting the
related areas recognized set of concepts, it is aimed at groups rather than individuals.
Ontology of the target
l Ontology goal is to capture the knowledge of related fields, providing a common
understanding of knowledge in this area, determine the areas of common recognition
of words, and from different levels of formal models of these terms given in (terms)
and the Lexicon clear definition of mutual relations.
Why Ontology?
l Because of the cross-system knowledge reuse and sharing of interest increases, the
result of the surge of interest in Ontology.
l knowledge-sharing problems: description of the different areas of the system when
using different concepts and terminology. It is difficult to extract knowledge from one
system to another system in use.
l Development of Reusable Ontology to Ontology promote sharing and reuse is an
important research goal.
l development support construction, consolidation and translation Ontology tool is
another objective of the study.
Ontology to support clear
l shared understanding between people
l interoperability between tools
l Engineering
l reusability
l definitions and concepts Thesaurus
l mathematics in physics playing the role of (content theories)
l adequate definition of the necessary concepts and "method"
l theory of common knowledge
Ontology as a product of engineering artificial
l Now, Ontology has gone beyond the scope of philosophy, but rather, and information
technology (such as: object-oriented systems) and artificial intelligence are closely
related.
l In this way, the field of artificial intelligence and information systems research on
Ontology and it must be made how to build and maintain Ontology practical useful
advice.
l a very practical point of view: Ontology is a need to construct the artificial product.
l many artificial products have a strong smell of Ontology, for example: glossary,
terminology, dictionaries, encyclopedias, knowledge base, database schema.
Comparison of Ontology and Knowledge Base
l some basic questions:
- Knowledge of the expression of a consensus yet?
- The terms used are clearly defined it?
- Easy to express the terminology used it?
- To facilitate knowledge reuse it?
- It stable?
- It is the starting point of a new project?
?The difference between Ontology and Knowledge Base
l Ontology for the Knowledge Base of a basic structure;
l Ontology provides a set of concepts and terminology to describe a particular area,
and for the concept of the nature of the field structure;
l These are accomplished through Ontology analysis;
l Then, the knowledge base can be used to express the reality of these terms or correct
knowledge of the virtual world.
Ontology analysis
l Ontology is the explicit knowledge of the structure. For a given field, it's
Ontology constitute any knowledge of the area, said core of the system. If there is no
support or knowledge of the Ontology concept system, then there would be no
knowledge of the vocabulary that exists. Therefore, the design of an effective
knowledge representation system and vocabulary of the first step is the effective area
of Ontology analysis, Ontology analysis did not do a good job will lead to
inconsistent knowledge base.
Knowledge representation language and knowledge base are created based on
Ontology analysis:
l Ontology of the terms and concepts and associated link; then
l Design of grammar, use of these concepts and relationships encoded knowledge.
Analogy
l database system design, software system design, are needed before the actual
implementation of the system analysis and design, the same way, knowledge-based
systems also need these steps.
Ontology and the "object-oriented" (OO) Methods
l Ontology design process and create the process of object-oriented software similar.
Objects, object properties and their processing application software-related mapping
various aspects of the field. Object-oriented system contains a useful analysis of the
field, are often reused in different applications.
Fundamental differences
l program class (Class) and target (Object) is on the data structure and, therefore,
object-oriented programming (OOP) may undermine the basic principles of Ontology.
l Ontology classes and objects must reflect the actual structure of the world.
l objects, relationships, status, events and processes that constitute a system, but it
itself does not explain what type of real-life existence of the entity, which is the field
of modeling personnel tasks.
Ontology analysis of the benefits
l we can express that knowledge in this area have similar needs to share this
knowledge on behalf of the language, thus avoiding the duplication of knowledge of
processes. Ontology sharing expertise in the areas that formed the basis of language.
Ontology modeling primitives
l Perez Ontology and others that can be organized according to classification, he
concludes Ontology contains five basic modeling primitives (Modeling Primitive).
These primitives are: class (classes), relations (relations), functions (functions),
axioms (axioms) and instance (instances). Usually the classes written concepts.
Concept
l very broad meaning of the concept, can refer to anything, such as job description,
function, behavior, strategy and reasoning and so on.
Relationship
l represents the relationship between the concepts in the field of interaction. Formally
defined as the n-dimensional subset of the Cartesian product: R: C1 × C2 × ? × Cn.
l such as: sub-class relations (subclass-of).
Function
l function is a special relationship. In this relationship before the n - 1 elements can be
only determined by the first n elements. Formal definition is as follows: F: C1 × C2
× ? × Cn-1 → Cn.
l such as Mother-of relations is a function, in which Mother-of (x, y) that y is
x's mother, obviously x can only determine his mother y.
Axiom
l never really asserted on behalf of justice, such as the concept of concept B is a
range.
Examples
l Representative examples of elements.
?l from the semantic analysis, that is an instance of an object, and the concept
expressed is a collection of objects, relations corresponding to the set of object tuples.
Commonly used definition of the concept frame (frame) structure, including the name
of the concept, and the relationship between the set of other concepts, as well as
natural language description of the concept.
l have four kinds of basic relations: part-of, kind-of, instance-of and attribute-of.
?
l In the actual application, not necessarily strictly in accordance with the above five
categories primitives to construct the Ontology. At the same time relations between
the concepts listed above are not limited to four kinds of basic relations, according to
the specific circumstances of a particular area of the relationship between the
definition of appropriate, to meet the application needs.
Ontology and Semantic Web
l as a tool for knowledge representation, Ontology and Semantic Web are very similar.
l They are expressed in the form of knowledge, and all can be flagged to indicate a
directed graph, suitable for logical reasoning.
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