Knowledge Object（知识物件）.PPT

Expert Systems sstseng 5.1 The meaning of Knowledge（知識） Classifications of knowledge（知識） Analogy to Wirth’s classic expression Algorithms + data structures = programs Knowledge + Inference = expert systems Levels The sequence of 12 numbers：137178007124 Without knowledge. This entire sequence may appear to be noise. Rule 1：IF Rain THEN Bring Raincoat Rule 2：IF Rain THEN Bring Umbrella Meta Rule 1：Try Rule 2 First Meta Rule 2：IF Ride a motorcycle THEN 　　　　　　Try Rule 1 First Meta knowledge is knowledge about knowledge and expertise. －would specify which knowledge base was applicable. Representation（表示法） 5.2 Backus - Naur form ( BNF ) 5.3 Ontology（本體論） Ontology一詞在90年代就開始被使用在人工智慧領域，描述知識的知識構成要素之間的關係。 Ontology的研究大致上可略為分為兩個方向： 針對特定的問題領域建立大量的Ontology 例如：建立某些領域詞彙的Ontology 研究Ontology的建構方法與表示方法 例如：利用XML（可延伸標記語言）或是RDF（資源描述格式） Ontology的發展主要是用來使知識分享和再用更為容易。 不同的研究對於Ontology的表示與描述有不同的方法，目前還未看到較一般化、通用的表示法 。 範例：使用RDF來描述適性化教材的Ontology 5.4 Semantic Network（語意網路） (Quillian 67 68) General Net A Semantic Net（語意網路） 「is a」 and 「a kind of」 5.5 PROLOG and Semantic Nets（語意網路） Essentials(本質、要素) of PROLOG Each of the statements above is a PROLOG predicate(述部) expression, or simply a predicate. 　Color(red).　　　　　　　　; red is a color 　father_of(Tom,John).　　　　 ; Tom is the father of John 　mother_of(Susan,John).　　　; Susan is the mother of John 　parents(Tom,Susan,John).　　 ; Tom and Susan are 　　　　　　　　　　　　　　 parents of John Predicates can also be expressed with relations such as the IS-A and HAS-A. 　is_a (red,color). 　has_a (John,father). 　has_a (John,mother). 　has_a (John,parents). Some additional predicates 　is_a (Tom,father). 　is_a (Susan,mother). 　is_a (Tom,parent). 　is_a (Susan,parent). Programs in PROLOG consist of facts and rules in the general form of goals. 　　　p:-p1,p2…pn. In which p is the rule’s head and the pi are the subgoals. The symbol,:-, is interpreted as an IF. parent (x,y) : - father (x,y). parent (x,y) : - mother(x,y). grandparent(x,y) :- parent (x,z) ,parent(z,y). and