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Knowledge representation is an issue that arises in both cognitive science and artificial intelligence. In cognitive science it is concerned with how people store and process information. In artificial intelligence (AI) the primary aim is to store knowledge so that programs can process it and achieve the verisimilitude of human intelligence. AI researchers have borrowed representation theories from cognitive science. Thus there are representation techniques such as frames, rules and semantic networks which have originated from theories of human information processing. Since knowledge is used to achieve intelligent behavior, the fundamental goal of knowledge representation is to represent knowledge in a manner as to facilitate inferencing i.e. drawing conclusions from knowledge.
Some issues that arise in knowledge representation from an AI perspective are:
- How do people represent knowledge?
- What is the nature of knowledge and how do we represent it?
- Should a representation scheme deal with a particular domain or should it be general purpose?
- How expressive is a representation scheme?
- Should the scheme be declarative or procedural?
There has been very little top-down discussion of the KR issues and research in this area is a well aged quiltwork. There are well known problems such as "spreading activation," (this is a problem in navigating a network of nodes) "subsumption" (this is concerned with selective inheritance; e.g. an ATV can be thought of as a specialization of a car but it inherits only particular characteristics) and "classification." For example a tomato could be classified both as a fruit and a vegetable.
In the field of artificial intelligence, problem solving can be simplified by an appropriate choice of knowledge representation. Representing the knowledge using a given technique may enable the domain to be represented. For example Mycin, a diagnostic expert system used a rule based representation scheme. An incorrect choice would defeat the representation endeavor; the analogy is to make computations in Hindu-Arabic numerals or in Roman numerals; long division is simpler in one and harder in the other. Likewise, there is no representation that can serve all purposes or make every problem equally approachable. Hondas humanoid robot AI redirects here. ...
Problem solving forms part of thinking. ...
The Hindu-Arabic numeral system (also called Algorism) is a positional decimal numeral system documented from the 9th century. ...
The system of Roman numerals is a numeral system originating in ancient Rome, and was adapted from Etruscan numerals. ...
In arithmetic, long division is a procedure for calculating the division of one integer, called the dividend, by another integer called the divisor, to produce a result called the quotient. ...
History in computer science
In computer science, particularly artificial intelligence, a number of representations have been devised to structure information. Computer science, or computing science, is the study of the theoretical foundations of information and computation and their implementation and application in computer systems. ...
Hondas humanoid robot AI redirects here. ...
"Knowledge Representation" (KR) is most commonly used to refer to representations intended for processing by modern computers, and in particular, for representations consisting of explicit objects (the class of all elephants, or Clyde a certain individual), and of assertions or claims about them ('Clyde is an elephant', or 'all elephants are grey'). Representing knowledge in such explicit form enables computers to draw conclusions from knowledge already stored ('Clyde is grey'). The tower of a personal computer. ...
Many KR methods were tried in the 1970s and early 1980s, such as heuristic question-answering, neural networks, theorem proving, and expert systems, with varying success. Medical diagnosis (e.g., Mycin) was a major application area, as were games such as chess. Look up Heuristic in Wiktionary, the free dictionary. ...
A neural network is an interconnected group of neurons. ...
Automated theorem proving (currently the most important subfield of automated reasoning) is the proving of mathematical theorems by a computer program. ...
An expert system is a class of computer programs developed by researchers in artificial intelligence during the 1970s and applied commercially throughout the 1980s. ...
Mycin was an expert system developed over 5 or six years in the early 1970s at the Stanford University, written in Lisp, by Edward Shortliffe under Bruce Buchanan and others; it derived from Dendral, but considerably modified it. ...
Chess is a recreational and competitive game for two players. ...
In the 1980s formal computer knowledge representation languages and systems arose. Major projects attempted to encode wide bodies of general knowledge; for example the "Cyc" project went through a large encyclopedia, encoding not the information itself, but the information a reader would need in order to understand the encyclopedia: naive physics; notions of time, causality, motivation; commonplace objects and classes of objects. The Cyc project is managed by Cycorp, Inc.; much but not all of the data is now freely available. Cyc is an artificial intelligence project that attempts to assemble a comprehensive ontology and database of everyday common sense knowledge, with the goal of enabling AI applications to perform human-like reasoning. ...
Cycorp, Inc. ...
Through such work, the difficulty of KR came to be better appreciated. In computational linguistics, meanwhile, much larger databases of language information were being built, and these, along with great increases in computer speed and capacity, made deeper KR more feasible. Computational linguistics is an interdisciplinary field dealing with the statistical and logical modeling of natural language from a computational perspective. ...
Several programming languages have been developed that are oriented to KR. Prolog developed in 1972 (see http://www.aaai.org/AITopics/bbhist.html#mod), but popularized much later, represents propositions and basic logic, and can derive conclusions from known premises. KL-ONE (1980s) is more specifically aimed at knowledge representation itself. Other listings of programming languages are: Categorical list of programming languages Generational list of programming languages Chronological list of programming languages Note: Esoteric programming languages have been moved to the separate List of esoteric programming languages. ...
Prolog is a logic programming language. ...
KL-ONE is a frame language. ...
In the electronic document world, languages were being developed to represent the structure of documents more explicitly, such as SGML and later XML. These facilitated information retrieval and data mining efforts, which have in recent years begun to relate to KR. The Web community is now especially interested in the Semantic Web, in which XML-based KR languages such as RDF, Topic Maps, and others can be used to make KR information available to Web systems. The Standard Generalized Markup Language (SGML) is a metalanguage in which one can define markup languages for documents. ...
The Extensible Markup Language (XML) is a general-purpose markup language. ...
Information retrieval (IR) is the science of searching for information in documents, searching for documents themselves, searching for metadata which describe documents, or searching within databases, whether relational stand-alone databases or hypertext networked databases such as the Internet or World Wide Web or intranets, for text, sound, images or...
Data mining (DM), also called Knowledge-Discovery in Databases (KDD) or Knowledge-Discovery and Data Mining, is the process of automatically searching large volumes of data for patterns using tools such as classification, association rule mining, clustering, etc. ...
The semantic web is an evolving extension of the World Wide Web in which web content can be expressed not only in natural language, but also in a form that can be understood, interpreted and used by software agents, thus permitting them to find, share and integrate information more easily. ...
Resource Description Framework (RDF) is a family of World Wide Web Consortium (W3C) specifications originally designed as a metadata model but which has come to be used as a general method of modeling information, through a variety of syntax formats. ...
Topic Maps are an ISO standard for the representation and interchange of knowledge, with an emphasis on the findability of information. ...
Links and structures While hyperlinks have come into widespread use, the closely related semantic link is not yet widely used. The mathematical table has been used since Babylonian times. More recently, these tables have been used to represent the outcomes of logic operations, such as truth tables, which were used to study and model Boolean logic, for example. Spreadsheets are yet another tabular representation of knowledge. Other knowledge representations are trees, by means of which the connections among fundamental concepts and derivative concepts can be shown. A hyperlink (often referred to as simply a link), is a reference or navigation element in a document to another section of the same document, another document, or a specified section of another document, that automatically brings the referred information to the user when the navigation element is selected by...
This article may be confusing for some readers, and should be edited to enhance clarity. ...
Before calculators were cheap and plentiful, people would use mathematical tables —lists of numbers showing the results of calculation with varying variables— to simplify and drastically speed up computation. ...
Babylon (in Arabic: بابل; in Syriac: Ü’Ü’Ü™Ü in Hebrew:בבל) was an ancient city in Mesopotamia (modern Al Hillah, Iraq), the ruins of which can be found in present-day Babil Province, about 50 miles (80 km) south of Baghdad. ...
Truth tables are a type of mathematical table used in logic to determine whether an expression is true or whether an argument is valid. ...
Screenshot of a spreadsheet made with OpenOffice. ...
A tree structure is a way of representing the hierarchical nature of a structure in a graphical form. ...
Visual representations, called a "plex" as developed by TheBrain Technologies are relatively new in the field of knowledge managment but give the user a way to visualise how one thought or idea is connected to other ideas enabling the possibility of moving from one thought to another in order to locate required information. The approach is not without its competitors. Other visual search tools are built by Convera Corporation, Entopia, Inc., EPeople Inc., and Inxight Software Inc.
Storage and manipulation One problem in knowledge representation consists of how to store and manipulate knowledge in an information system in a formal way so that it may be used by mechanisms to accomplish a given task. Examples of applications are expert systems, machine translation systems, computer-aided maintenance systems and information retrieval systems (including database front-ends). Personification of knowledge (Greek Επιστημη, Episteme) in Celsus Library in Ephesos, Turkey. ...
The term information system has the following meanings: 1. ...
An expert system, also known as a knowledge based system, is a computer program that contains some of the subject-specific knowledge of one or more human experts. ...
Machine translation (MT) is a form of translation where a computer program analyses the text in one language - the source text - and then attempts to produce another, equivalent text in another language - the target text - without human intervention. ...
The first computer-aided maintenance software came from DEC in the 1980s to configure VAX computers. ...
Information retrieval (IR) is the science of searching for information in documents, searching for documents themselves, searching for metadata which describe documents, or searching within databases, whether relational stand-alone databases or hypertext networked databases such as the Internet or World Wide Web or intranets, for text, sound, images or...
Semantic networks may be used to represent knowledge. Each node represents a concept and arcs are used to define relations between the concepts. One of the most expressive and comprehensively described knowledge representation paradigms along the lines of semantic networks is MultiNet (an acronym for Multilayered Extended Semantic Networks). A semantic network is often used as a form of knowledge representation. ...
A concept is an abstract idea or a mental symbol, typically associated with a corresponding representation in language or symbology, that denotes all of the objects in a given category or class of entities, interactions, phenomena, or relationships between them. ...
The relational model for database management is a database model based on predicate logic and set theory. ...
Multilayered extended semantic networks (abbreviated MultiNets) are both a knowledge representation paradigm and a language for meaning representation of natural language expressions. ...
From the 1960s, the knowledge frame or just frame has been used. Each frame has its own name and a set of attributes, or slots which contain values; for instance, the frame for house might contain a color slot, number of floors slot, etc. The 1960s decade refers to the years from January 1, 1960 to December 31, 1969, inclusive. ...
In psychology and cognitive science, a schema is a mental structure that represents some aspect of the world. ...
Using frames for expert systems is an application of object-oriented programming, with inheritance of features described by the "is-a" link. However, there has been no small amount of inconsistency in the usage of the "is-a" link: Ronald J. Brachman wrote a paper titled "What IS-A is and isn't", wherein 29 different semantics were found in projects whose knowledge representation schemes involved an "is-a" link. Other links include the "has-part" link. An expert system is a class of computer programs developed by researchers in artificial intelligence during the 1970s and applied commercially throughout the 1980s. ...
Object-oriented programming (OOP) is a computer programming paradigm in which a software system is modeled as a set of objects that interact with each other. ...
This article or section does not adequately cite its references or sources. ...
In computer science, the term inheritance may be applied to a variety of situations in which certain characteristics are passed on from one context to another. ...
Consistency has three technical meanings: In mathematics and logic, as well as in theoretical physics, it refers to the proposition that a formal theory or a physical theory contains no contradictions. ...
Ronald J. Brachman works at DARPA as a Program Director of the Cognitive Systems area. ...
Frame structures are well-suited for the representation of schematic knowledge and stereotypical cognitive patterns. The elements of such schematic patterns are weighted unequally, attributing higher weights to the more typical elements of a schema. A pattern is activated by certain expectations: If a person sees a big bird, he or she will classify it rather as a sea eagle than a golden eagle, assuming that his or her "sea-scheme" is currently activated and his "land-scheme" is not.
Frame representations are object-centered in the same sense as semantic networks are: All the facts and properties connected with a concept are located in one place - there is no need for costly search processes in the database. A semantic network is often used as a form of knowledge representation. ...
A script is a type of frame that describes what happens temporally; the usual example given is that of describing going to a restaurant. The steps include waiting to be seated, receiving a menu, ordering, etc. Toms Restaurant, a restaurant in New York made familiar by Suzanne Vega and the television sitcom Seinfeld A restaurant is an establishment that serves prepared food and beverages to order, to be consumed on the premises. ...
The different solutions can be arranged in a so-called semantic spectrum with respect to their semantic expressivity. The semantic spectrum describes a series of technologies for creating increasingly precise definitions for Data elements. ...
Language and notation Some people think it would be best to represent knowledge in the same way that it is represented in the human mind, which is the only known working intelligence so far, or to represent knowledge in the form of human language. Richard L. Ballard Ph.D., for example, has developed a theory-based semantics system that is language independent, which claims to capture and reason with the same concepts and theory as people. The formula underlying theory-based semantics is: Knowledge=Theory+Information. Most all conventional applications and database systems are language-based. Unfortunately, we don't know how knowledge is represented in the human mind, or how to manipulate human languages the same way that the human mind does it. One clue is that primates know how to use point and click user interfaces; thus the gesture-based interface appears to be part of our cognitive apparatus, a modality which is not tied to verbal language, and which exists in other animals besides humans. The mind is the term most commonly used to describe the higher functions of the human brain, particularly those of which humans are subjectively conscious, such as personality, thought, reason, memory, intelligence and emotion. ...
Intelligence is the mental capacity to reason, plan, solve problems, think abstractly, comprehend ideas and language, and learn. ...
The term natural language is used to distinguish languages spoken by humans for general-purpose communication from constructs such as computer-programming languages or the languages used in the study of formal logic, especially mathematical logic. ...
Point and click describes the simple action of a computer user moving a cursor to a certain location on a screen (point) and then clicking a mouse button, usually the left one (click), or other pointing device. ...
In music, modality is the subject concerning certain diatonic scales known as modes (e. ...
Animalia redirects here. ...
Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are bipedal primates belonging to the mammalian species Homo sapiens (Latin: wise man or knowing man) under the family Hominidae (the great apes). ...
For this reason, various artificial languages and notations have been proposed for representing knowledge. They are typically based on logic and mathematics, and have easily parsed grammars to ease machine processing. They usually fall into the broad domain of ontologies. An artificial or constructed language (known colloquially as a conlang among aficionados), is a language whose vocabulary and grammar were specifically devised by an individual or small group, rather than having naturally evolved as part of a culture as with natural languages. ...
The term notation can be used in several contexts. ...
Logic, from Classical Greek λόγος logos (the word), is the study of the principles and criteria of valid inference and demonstration. ...
Euclid, Greek mathematician, 3rd century BC, as imagined by by Raphael in this detail from The School of Athens. ...
For the surname, see Grammer. ...
Computation can be defined as finding a solution to a problem from given inputs by means of an algorithm. ...
In both computer science and information science, an ontology is a data model that represents a domain and is used to reason about the objects in that domain and the relations between them. ...
Notation The recent fashion in knowledge representation languages is to use XML as the low-level syntax. This tends to make the output of these KR languages easy for machines to parse, at the expense of human readability. The Extensible Markup Language (XML) is a general-purpose markup language. ...
// Information processing In information processing, output is the process of transmitting information by an object (verb usage). ...
In grammar and linguistics, parsing is the process by which a person makes sense of a sentence, usually by breaking it down into words or phrases. ...
// In the sciences, readability is a measure of an instruments ability to display incremental changes in its output value. ...
First-order predicate calculus is commonly used as a mathematical basis for these systems, to avoid excessive complexity. However, even simple systems based on this simple logic can be used to represent data that is well beyond the processing capability of current computer systems: see computability for reasons. First-order predicate calculus or first-order logic (FOL) permits the formulation of quantified statements such as there exists an x such that. ...
Complexity in general usage is the opposite of simplicity. ...
Computation can be defined as finding a solution to a problem from given inputs by means of an algorithm. ...
Examples of notations:
DATR is a language for lexical knowledge representation. ...
Look up lexicon in Wiktionary, the free dictionary. ...
Resource Description Framework (RDF) is a family of World Wide Web Consortium (W3C) specifications originally designed as a metadata model but which has come to be used as a general method of modeling information, through a variety of syntax formats. ...
The term notation can be used in several contexts. ...
In philosophy, an object is a thing, an entity, or a being. ...
Languages Examples of artificial languages used primarily for knowledge representation include: An artificial or constructed language (known colloquially as a conlang among aficionados), is a language whose vocabulary and grammar were specifically devised by an individual or small group, rather than having naturally evolved as part of a culture as with natural languages. ...
- CycL
- IKL
- KIF
- Loom
- OWL
- KM : the Knowledge Machine (frame-based language used for knowledge representation work)
CycL was originally a frame language used by Doug Lenats Cyc Artificial Intelligence project. ...
Knowledge Interchange Format was created to serve as a syntax for first order logic that is easy for computers to process. ...
Loomâ„¢ is a knowledge representation language developed by researchers in the Artificial Intelligence research group at the University of Southern Californias Information Sciences Institute. ...
The Web Ontology Language (OWL) is a language for defining and instantiating Web ontologies. ...
KM, the Knowledge Machine, is a frame-based language used for knowledge representation work. ...
Frame language is a metalanguage. ...
Formalisms and Methods Knowledge representation formalisms and methods is the name of section I.2.4 of the ACM Computing Classification System. The ACM Computing Classification System is a subject classification system for computer science devised by the Association for Computing Machinery. ...
This section lies under:
- The top-level category, I Computing Methodologies, and
- The second-level category, I.2 Artificial Intelligence.
It comprises the following topics: - frames and scripts
- Modal logic
- Predicate logic
- Relation systems
- Representation languages
- Representations (procedural and rule-based)
- Semantic networks
- Temporal logic
Frame language is a metalanguage. ...
Scripts were developed in the early AI work by Roger Schank and his research group, and are a method of representing procedural knowledge. ...
In philosophical logic, a modal logic is any logic for handling modalities: concepts like possibility, impossibility, and necessity. ...
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A semantic network is often used as a form of knowledge representation. ...
In logic, the term temporal logic is used to describe any system of rules and symbolism for representing, and reasoning about, propositions qualified in terms of time. ...
See also To meet Wikipedias quality standards, this article or section may require cleanup. ...
Knowledge management comprises a range of practices used by organisations to identify, create, represent, and distribute knowledge for reuse, awareness, and learning across the organisations. ...
Data mining, also known as knowledge-discovery in databases (KDD), is the practice of automatically searching large stores of data for patterns. ...
Hondas humanoid robot AI redirects here. ...
Computability logic is a formal theory of computability, introduced by Giorgi Japaridze in 2003. ...
Description logics (DL) are a family of knowledge representation languages which can be used to represent the terminological knowledge of an application domain in a structured and formally well-understood way. ...
Douglas B. Lenat (born in 1950) is the CEO of Cycorp, Inc. ...
Cyc is an artificial intelligence project that attempts to assemble a comprehensive ontology and database of everyday common sense knowledge, with the goal of enabling AI applications to perform human-like reasoning. ...
Metadata is data about data. ...
Multilayered extended semantic networks (abbreviated MultiNets) are both a knowledge representation paradigm and a language for meaning representation of natural language expressions. ...
Cyc is an artificial intelligence project which attempts to assemble a comprehensive ontology and database of everyday common-sense knowledge, with the goal of enabling AI applications to perform human-like reasoning. ...
The semantic web is an evolving extension of the World Wide Web in which web content can be expressed not only in natural language, but also in a form that can be understood, interpreted and used by software agents, thus permitting them to find, share and integrate information more easily. ...
Scientific modeling is the process of generating abstract or conceptual models. ...
Morphological analysis is a technique developed by Fritz Zwicky (1966, 1969) for exploring all the possible solutions to a multi-dimensional, non-quantified problem complex. ...
Topic Maps are an ISO standard for the representation and interchange of knowledge, with an emphasis on the findability of information. ...
References - Amaravadi, C. S., “Knowledge Management for Administrative Knowledge,” Expert Systems, 25(2), pp 53-61, May 2005.
- Ronald J. Brachman; What IS-A is and isn't. An Analysis of Taxonomic Links in Semantic Networks; IEEE Computer, 16 (10); October 1983 [1]
- Jean-Luc Hainaut, Jean-Marc Hick, Vincent Englebert, Jean Henrard, Didier Roland: Understanding Implementations of IS-A Relations. ER 1996: 42-57 [2]
- Hermann Helbig: Knowledge Representation and the Semantics of Natural Language, Springer, Berlin, Heidelberg, New York 2006
- Arthur B. Markman: Knowledge Representation Lawrence Erlbaum Associates, 1998
- Michael Negnevitsky: Artificial Intelligence, A Guide to Intelligent Systems, Pearson Education Limited, 2002
- John F. Sowa: Knowledge Representation: Logical, Philosophical, and Computational Foundations. Brooks/Cole: New York, 2000
- Adrian Walker, Michael McCord, John F. Sowa, and Walter G. Wilson: Knowledge Systems and Prolog, Second Edition, Addison-Wesley, 1990
Ronald J. Brachman works at DARPA as a Program Director of the Cognitive Systems area. ...
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