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Subsumption Relation
In knowledge representation, object-oriented programming and design (see object-oriented program architecture), is-a (is_a or is a) is a subsumption relationship between abstractions (e.g. types, classes), wherein one class ''A'' is a subclass of another class ''B'' (and so ''B'' is a superclass of ''A''). In other words, type A is a subtype of type B when A's specification implies B's specification. That is, any object (or class) that satisfies A's specification also satisfies B's specification, because B's specification is weaker. The ''is-a'' relationship is to be contrasted with the ''has-a'' (''has_a'' or ''has a'') relationship between types (classes); confusing the relations ''has-a'' and ''is-a'' is a common error when designing a model (e.g., a computer program) of the real-world relationship between an object and its subordinate. The ''is-a'' relationship may also be contrasted with the '' instance-of'' relationship between objects (instances) and types (classes) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knowledge Representation
Knowledge representation and reasoning (KRR, KR&R, KR²) is the field of artificial intelligence (AI) dedicated to representing information about the world in a form that a computer system can use to solve complex tasks such as diagnosing a medical condition or having a dialog in a natural language. Knowledge representation incorporates findings from psychology about how humans solve problems and represent knowledge in order to design formalisms that will make complex systems easier to design and build. Knowledge representation and reasoning also incorporates findings from logic to automate various kinds of ''reasoning'', such as the application of rules or the relations of sets and subsets. Examples of knowledge representation formalisms include semantic nets, systems architecture, frames, rules, and ontologies. Examples of automated reasoning engines include inference engines, theorem provers, and classifiers. History The earliest work in computerized knowledge rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type–token Distinction
The type–token distinction is the difference between naming a ''class'' (type) of objects and naming the individual ''instances'' (tokens) of that class. Since each type may be exemplified by multiple tokens, there are generally more tokens than types of an object. For example, the sentence " A rose is a rose is a rose" contains three word types: three word tokens of the type ''a'', three word tokens of the type ''rose'', and two word tokens of the type ''is''. The distinction is important in disciplines such as logic, linguistics, metalogic, typography, and computer programming. Overview The type–token distinction separates ''types'' (abstract descriptive concepts) from ''tokens'' (objects that instantiate concepts). For example, in the sentence "''the bicycle is becoming more popular''" the word ''bicycle'' represents the abstract concept of bicycles, and is thus a type, whereas in the sentence "''the bicycle is in the garage''", it represents a particular object, and is ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subtype Polymorphism
In programming language theory, subtyping (also subtype polymorphism or inclusion polymorphism) is a form of type polymorphism in which a subtype is a datatype that is related to another datatype (the supertype) by some notion of substitutability, meaning that program elements, typically subroutines or functions, written to operate on elements of the supertype can also operate on elements of the subtype. If S is a subtype of T, the subtyping relation (written as , , or ) means that any term of type S can ''safely be used'' in ''any context'' where a term of type T is expected. The precise semantics of subtyping here crucially depends on the particulars of how ''"safely be used"'' and ''"any context"'' are defined by a given type formalism or programming language. The type system of a programming language essentially defines its own subtyping relation, which may well be trivial, should the language support no (or very little) conversion mechanisms. Due to the sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Instance (computer Science)
In a computer system, any time a new context is created based on some model, it is said that the model has been instantiated. In practice, this instance usually has a data structure in common with other instances, but the values stored in the instances are separate. Changing the values in one instance will then not interfere with the values of some other instance. A compute instance can be software or hardware which can run code, for example a CPU, GPU or a virtual machine. Computer graphics In computer graphics, a polygonal model can be instantiated in order to be drawn several times in different locations in a scene. This is a technique that can be used to improve the performance of rendering, since the work needed to display each instance overlaps. Object-oriented programming In object-oriented programming (OOP), an instance is a concrete occurrence of any object, existing usually during the runtime of a computer program. Formally, "instance" is synonymous with "object" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Container (abstract Data Type)
In computer science, a container is a class or a data structureEntry ''data structure'' in the Encyclopædia Britannica (2009Online entryAccessed 4 Oct 2011. whose instances are collections of other objects. In other words, they store objects in an organized way that follows specific access rules. The size of the container depends on the number of objects (elements) it contains. Underlying (inherited) implementations of various container types may vary in size, complexity and type of language, but in many cases they provide flexibility in choosing the right implementation for any given scenario. Container data structures are commonly used in many types of programming languages. Function and properties Containers can be characterized by the following three properties: * ''access'', that is the way of accessing the objects of the container. In the case of arrays, access is done with the array index. In the case of stacks, access is done according to the LIFO (last in, first o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Containment (computer Programming)
In computer science, object composition and object aggregation are closely related ways to combine objects or data types into more complex ones. In conversation the distinction between composition and aggregation is often ignored. Common kinds of compositions are objects used in object-oriented programming, tagged unions, sets, sequences, and various graph structures. Object compositions relate to, but are not the same as, data structures. Object composition refers to the logical or conceptual structure of the information, not the implementation or physical data structure used to represent it. For example, a sequence differs from a set because (among other things) the order of the composed items matters for the former but not the latter. Data structures such as arrays, linked lists, hash tables, and many others can be used to implement either of them. Perhaps confusingly, some of the same terms are used for both data structures and composites. For example, " binary tree" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object Composition
In computer science, object composition and object aggregation are closely related ways to combine objects or data types into more complex ones. In conversation the distinction between composition and aggregation is often ignored. Common kinds of compositions are objects used in object-oriented programming, tagged unions, sets, sequences, and various graph structures. Object compositions relate to, but are not the same as, data structures. Object composition refers to the logical or conceptual structure of the information, not the implementation or physical data structure used to represent it. For example, a sequence differs from a set because (among other things) the order of the composed items matters for the former but not the latter. Data structures such as arrays, linked lists, hash tables, and many others can be used to implement either of them. Perhaps confusingly, some of the same terms are used for both data structures and composites. For example, "binary tree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Part-of
In linguistics, meronymy () is a semantic relation between a meronym denoting a part and a holonym denoting a whole. In simpler terms, a meronym is in a ''part-of'' relationship with its holonym. For example, ''finger'' is a meronym of ''hand'' which is its holonym. Similarly, ''engine'' is a meronym of ''car'' which is its holonym. Holonymy () is the converse of meronymy. A closely related concept is that of mereology, which specifically deals with part–whole relations and is used in logic. It is formally expressed in terms of first-order logic. A meronymy can also be considered a partial order. Meronym and holonym refer to ''part'' and ''whole'' respectively, which is not to be confused with hyponym which refers to ''type''. For example, a holonym of ''leaf'' might be ''tree'' (a leaf is a part of a tree), whereas a hyponym of ''oak tree'' might be ''tree'' (an oak tree is a type of tree). See also * Has-a * Hyponymy and hypernymy * Is-a * Mereological nihilism * S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Composition (object-oriented Programming)
In computer science, object composition and object aggregation are closely related ways to combine objects or data types into more complex ones. In conversation the distinction between composition and aggregation is often ignored. Common kinds of compositions are objects used in object-oriented programming, tagged unions, sets, sequences, and various graph structures. Object compositions relate to, but are not the same as, data structures. Object composition refers to the logical or conceptual structure of the information, not the implementation or physical data structure used to represent it. For example, a sequence differs from a set because (among other things) the order of the composed items matters for the former but not the latter. Data structures such as arrays, linked lists, hash tables, and many others can be used to implement either of them. Perhaps confusingly, some of the same terms are used for both data structures and composites. For example, " binary tre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aggregation (object-oriented Programming)
In computer science, object composition and object aggregation are closely related ways to combine objects or data types into more complex ones. In conversation the distinction between composition and aggregation is often ignored. Common kinds of compositions are objects used in object-oriented programming, tagged unions, sets, sequences, and various graph structures. Object compositions relate to, but are not the same as, data structures. Object composition refers to the logical or conceptual structure of the information, not the implementation or physical data structure used to represent it. For example, a sequence differs from a set because (among other things) the order of the composed items matters for the former but not the latter. Data structures such as arrays, linked lists, hash tables, and many others can be used to implement either of them. Perhaps confusingly, some of the same terms are used for both data structures and composites. For example, " binary tre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meronym
In linguistics, meronymy () is a semantic relation between a meronym denoting a part and a holonym denoting a whole. In simpler terms, a meronym is in a ''part-of'' relationship with its holonym. For example, ''finger'' is a meronym of ''hand'' which is its holonym. Similarly, ''engine'' is a meronym of ''car'' which is its holonym. Holonymy () is the converse of meronymy. A closely related concept is that of mereology, which specifically deals with part–whole relations and is used in logic. It is formally expressed in terms of first-order logic. A meronymy can also be considered a partial order. Meronym and holonym refer to ''part'' and ''whole'' respectively, which is not to be confused with hyponym which refers to ''type''. For example, a holonym of ''leaf'' might be ''tree'' (a leaf is a part of a tree), whereas a hyponym of ''oak tree'' might be ''tree'' (an oak tree is a type of tree). See also * Has-a * Hyponymy and hypernymy * Is-a * Mereological nihilism * Synec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holonym
In linguistics, meronymy () is a semantic relation between a meronym denoting a part and a holonym denoting a whole. In simpler terms, a meronym is in a ''part-of'' relationship with its holonym. For example, ''finger'' is a meronym of ''hand'' which is its holonym. Similarly, ''engine'' is a meronym of ''car'' which is its holonym. Holonymy () is the converse of meronymy. A closely related concept is that of mereology, which specifically deals with part–whole relations and is used in logic. It is formally expressed in terms of first-order logic. A meronymy can also be considered a partial order. Meronym and holonym refer to ''part'' and ''whole'' respectively, which is not to be confused with hyponym which refers to ''type''. For example, a holonym of ''leaf'' might be ''tree'' (a leaf is a part of a tree), whereas a hyponym of ''oak tree'' might be ''tree'' (an oak tree is a type of tree). See also * Has-a * Hyponymy and hypernymy * Is-a * Mereological nihilism * Synec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
