What is Ontology? – DATAVERSITY
entity-relationship data model. This paper presents a system for entity- relationship data model semantic evaluation that is based on comparing ontology . ontology, conceptualization and metamodel, as well as on the relations between these .. Relationship model  commits to a worldview that accounts for the. This tells us that the Explorer is the model that replaced the Bronco. This example also illustrates that the relation has a direction of.
Basic requirements for visualization module are as follows: Examples of visualization are shown in Figure 5. The classes have different colors. Class Post, which represent note on portal, has nine fields. Also, there are six instances of class Post.
The ontology model for classification and recognition of marine objects 2. Features of semantic modeling technology The main feature of semantic technology is to store and maintain the integrity of semantics meaning of knowledge separately from the contents of data files and from the code of the programs that implement them [ 4 ].
Semantic simulation technology differs from traditional methods that combine the meaning of data and the processing procedures directly in the program code.
This often leads to the need for a radical manual redevelopment of data structures and total revision of programs during their development or migrate to another platform. Semantic technologies allow obtaining logical conclusions based on the rules of conceptual models and perform automatic redesign of data structures.
Experience the semantic modeling of intelligent systems using ontologies indicates that any subject domain SD can be described considerable number of ontologies.
Therefore, it is advisable for the developer to apply such methodology and tools, which allow not only to develop an ontology model, but also to correct it in the process of mastering it, and understanding the features of its functioning, been aimed at the most correct model development. Under the term ontology, we understood a system of concepts domain, which is represented by a set of entities and their properties, interconnected relations, in order to develop knowledge bases on their basis.
Consequently, the main purpose of ontological modeling is to develop a formalized knowledge model of the domain, which is stored electronically and may further improved through a more in-depth understanding of the features of the subject domain. In this case, the semantic modeling process has been performed using the open knowledge base connectivity OKBC [ 6 ].
The formal semantics of the subject domain on the OWL describes how to obtain logical investigations, having the ontology of SD, which is to obtain facts that are not represented literally in the ontology, but logically follow from its semantics.
Methodological aspects of semantic modeling using web ontology language An applied ontology should describe concepts that depend both on the ontology of tasks and on the ontology of the subject domain. The purpose of the applied ontology is to develop an electronic model of knowledge that allows: The OWL language contains elements such as classes, properties and individuals [ 7 ]. All concepts of the subject domain are divided into classes, subclasses and instances copies. The tag describes classes as: Definition of the concepts of the subject domain, that is, the basic concepts such as classes, entities, categories Active Ontology, Entities and Classes that describe the SD; Determination of the set of properties, which describes the properties of the concepts of SD and allow in the final sense to develop a knowledge base of the domain.
This is realized through the mechanisms of axiom definition Axiom or facet Value. For example, the maximum speed for terrestrial objects is limited to the value; Formation of knowledge base using the mechanism of description of instances of the knowledge base and its filling Individual by class ; Development of typical query patterns for the knowledge base using the query language, DL Query and the output machine, Reasoner; Checking the correctness of the functioning of the ontological model of SD from the point of view of its correspondence to the initial goals and the task and finding gaps in the ontology using the OntoGraf research mechanism.
The evaluation is based on the analysis of the results of testing by various output machines Reasoner and the compilation of various types of requests; Development of a strategy for improving the ontological model of SD and carrying out the relevant work. Taking into account the complexity and ambiguity that arises in the process of describing the subject domain, modern science offers several approaches to the creation of ontology: The use of this method requires the definition of the most general concepts of the domain, with further detail of objects in the class hierarchy and the concepts of the subject domain.
Down to the top. This approach begins with the definition of detailed and specific classes the end of the tree of the hierarchyfollowed by grouping into more general concepts. Combination of the first two methods.
Ontology components - Wikipedia
First, a description of the concepts that are fully understood, then associate them into groups and develop more complex concepts of subject domain.
Definition of the depth and scope of the subject domain It is advisable to start developing an ontology with the purpose of determining its scope and scale. That is, the answer to a few basic questions: Which SD will cover the ontology? What types of questions should answer information in ontology be? Some examples of classes: Vehicle, the class of all vehicles, or the abstract object that can be described by the criteria for being a vehicle. Car, the class of all cars, or the abstract object that can be described by the criteria for being a car.
Class, representing the class of all classes, or the abstract object that can be described by the criteria for being a class. Thing, representing the class of all things, or the abstract object that can be described by the criteria for being a thing and not nothing. Ontologies vary on whether classes can contain other classes, whether a class can belong to itself, whether there is a universal class that is, a class containing everythingetc. Sometimes restrictions along these lines are made in order to avoid certain well-known paradoxes.
- Ontologies and Data Models – are they the same? » TopQuadrant, Inc
- Ontology components
- What is Ontology?
The classes of an ontology may be extensional or intensional in nature. A class is extensional if and only if it is characterized solely by its membership. More precisely, a class C is extensional if and only if for any class C', if C' has exactly the same members as C, then C and C' are identical. If a class does not satisfy this condition, then it is intensional. While extensional classes are more well-behaved and well understood mathematically, as well as less problematic philosophically, they do not permit the fine grained distinctions that ontologies often need to make.
For example, an ontology may want to distinguish between the class of all creatures with a kidney and the class of all creatures with a heart, even if these classes happen to have exactly the same members.
Examples of Ontology Model Usage in Engineering Fields
In most upper ontologies, the classes are defined intensionally. Intensionally defined classes usually have necessary conditions associated with membership in each class. Some classes may also have sufficient conditions, and in those cases the combination of necessary and sufficient conditions make that class a fully defined class. Importantly, a class can subsume or be subsumed by other classes; a class subsumed by another is called a subclass or subtype of the subsuming class or supertype.
For example, Vehicle subsumes Car, since necessarily anything that is a member of the latter class is a member of the former.
The subsumption relation is used to create a hierarchy of classes, typically with a maximally general class like Anything at the top, and very specific classes like Ford Explorer at the bottom. The critically important consequence of the subsumption relation is the inheritance of properties from the parent subsuming class to the child subsumed class.What is an Ontology
Thus, anything that is necessarily true of a parent class is also necessarily true of all of its subsumed child classes. In some ontologies, a class is only allowed to have one parent single inheritancebut in most ontologies, classes are allowed to have any number of parents multiple inheritanceand in the latter case all necessary properties of each parent are inherited by the subsumed child class.
Thus a particular class of animal HouseCat may be a child of the class Cat and also a child of the class Pet. A partition is a set of related classes and associated rules that allow objects to be classified by the appropriate subclass. The rules correspond with the aspect values that distinguish the subclasses from the superclasses.
For example, to the right is the partial diagram of an ontology that has a partition of the Car class into the classes 2-Wheel Drive Car and 4-Wheel Drive Car. The partition rule or subsumption rule determines if a particular car is classified by the 2-Wheel Drive Car or the 4-Wheel Drive Car class.
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If the partition rule s guarantee that a single Car cannot be in both classes, then the partition is called a disjoint partition. If the partition rules ensure that every concrete object in the super-class is an instance of at least one of the partition classes, then the partition is called an exhaustive partition.
Attributes[ edit ] Objects in an ontology can be described by relating them to other things, typically aspects or parts. These related things are often called attributes, although they may be independent things.
Each attribute can be a class or an individual. The kind of object and the kind of attribute determine the kind of relation between them. A relation between an object and an attribute express a fact that is specific to the object to which it is related.
For example, the Ford Explorer object has attributes such as: Ontologies are only true ontologies if concepts are related to other concepts the concepts do have attributes. If that is not the case, then you would have either a taxonomy if hyponym relationships exist between concepts or a controlled vocabulary. These are useful, but are not considered true ontologies. Relationships[ edit ] Relationships also known as relations between objects in an ontology specify how objects are related to other objects.