[工学]浙江大学研究生《人工智能引论》课件.ppt

What’s Knowledge Representation? Knowledge representation is the application of logic and ontology to the task of constructing computable models for some domain. Knowledge representation is a multidisciplinary subject that applies theories and techniques from three other fields: Logic provides the formal structure and rules of inference. Ontology defines the kinds of things that exist in the application domain. Computation supports the applications that distinguish knowledge representation from pure philosophy. 知识表示 ＝ 逻辑＋本体论＋可计算模型 Logic, Ontology, and Computation Logic（逻辑） Analyzing a problem Logic is pure form（逻辑是一种“纯形式”，可与“内容”脱开来研究） Without logic, a knowledge representation is vague, with no criteria for determining whether statements are redundant or contradictory. Ontology（本体论） Identifying the kinds of things Ontology provides the content that is expressed in that form Without ontology, the terms and symbols are ill-defined, confused, and confusing. （本体论是 “形式＋内容”的有机结合体） Computation（计算） Mapping logic and ontology to a computable form. Without computable models, the logic and ontology cannot be implemented in computer programs. （计算是将 “逻辑”和“本体论”映射成可计算的形式） Philosophical Background: part one Heraclitus（赫拉克里特） In the sixth century B.C., the Greek philosopher Claimed that all things flow, as his famous saying, “One cannot step twice into the same river.” (人不能两次跨入同一条河流) Emphasized the intangible logos – translated variously as word, speech, or reason: “all things (panta) come into being according to this logos.” (万物都是藉着“道”logos而造的) Logos可翻译成中文的“道”、“律”等。 Philosophical Background: part four Plato adopted Heraclitus’s distinction between the ever-changing flow of all things and the intangible logos that determines that flow. In analyzing the concepts underlying the logos, Plato proposed the intangible, unchanging mathematical forms or ideas as the true reality, which is reflected in the changeable, illusory flow of physical things. Aristotle’s Categories – part one Aristo