Loom is a knowledge representation language developed by researchers in the

artificial intelligence Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech r ...

research group at the

University of Southern California , mottoeng = "Let whoever earns the palm bear it" , religious_affiliation = Nonsectarian—historically Methodist , established = , accreditation = WSCUC , type = Private research university , academic_affiliations = , endowment = $8.1 ...

Information Sciences Institute The USC Information Sciences Institute (ISI) is a component of the University of Southern California (USC) Viterbi School of Engineering, and specializes in research and development in information processing, computing, and communications techn ...

. The leader of the Loom project and primary architect for Loom was Robert MacGregor. The research was primarily sponsored by the Defense Advanced Research Projects Agency (DARPA). Loom is a frame-based language in the tradition of

KL-ONE KL-ONE (pronounced "kay ell won") is a knowledge representation system in the tradition of semantic networks and frames; that is, it is a frame language. The system is an attempt to overcome semantic indistinctness in semantic network represen ...

. As with KL-ONE, Loom has a formal semantics that maps declarations in Loom to statements in

set theory Set theory is the branch of mathematical logic that studies sets, which can be informally described as collections of objects. Although objects of any kind can be collected into a set, set theory, as a branch of mathematics, is mostly conce ...

and

First Order Logic First-order logic—also known as predicate logic, quantificational logic, and first-order predicate calculus—is a collection of formal systems used in mathematics, philosophy, linguistics, and computer science. First-order logic uses quantifie ...

. This formal semantics enables a type of theorem prover engine called a classifier. The classifier can analyze Loom models (known as

ontologies In computer science and information science, an ontology encompasses a representation, formal naming, and definition of the categories, properties, and relations between the concepts, data, and entities that substantiate one, many, or all domains ...

) and deduce various things about the model. For example, the classifier can discover new classes or change the subclass/superclass relations in the model. The classifier can also detect inconsistencies in the model declaration. This is a very powerful and fairly unusual capability in that it is capable of doing analysis at the ontology level, the level of declarations rather than at the implementation level as most inference engines do. The Loom project's goal is the development and fielding of advanced tools for

knowledge representation and reasoning 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 medic ...

in artificial intelligence. Specifically to enable code to be generated from provably valid domain models. Loom is a language and environment for constructing intelligent applications. At its heart is a

system that combines a Frame-based language with an automatic classifier engine.

Declarative knowledge In epistemology, descriptive knowledge (also known as propositional knowledge, knowing-that, declarative knowledge, or constative knowledge) is knowledge that can be expressed in a declarative sentence or an indicative proposition. "Knowing-that" c ...

in Loom consists of definitions, rules, facts, and default rules. A deductive engine called a classifier utilizes

forward chaining Forward chaining (or forward reasoning) is one of the two main methods of reasoning when using an inference engine and can be described logically as repeated application of ''modus ponens''. Forward chaining is a popular implementation strategy ...

, semantic unification, and object-oriented truth maintenance technologies in order to compile the declarative knowledge into a network designed to efficiently support on-line deductive query processing. The Loom system implements a logic-based pattern matcher that drives a production rule facility and a pattern-directed method dispatching facility that supports the definition of

object-oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of " objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form of p ...

methods. The high degree of integration between Loom's declarative and procedural components permits programmers to utilize logic programming, production rule, and object-oriented programming paradigms in a single application. Loom can also be used as a deductive layer that overlays an ordinary

CLOS Clos may refer to: People * Clos (surname) Other uses * CLOS, Command line-of-sight, a method of guiding a missile to its intended target * Clos network, a kind of multistage switching network * Clos (vineyard), a walled vineyard; used in Fran ...

(Common Lisp Object System) network. In this mode, users can obtain many of the benefits of using Loom without impacting the function or performance of their CLOS-based applications. Loom has recently been succeeded by PowerLoom.

References

External links

Loom
Knowledge representation languages Declarative programming languages Common Lisp (programming language) software Ontology (information science) {{compu-lang-stub