Computation Of Categorial Expressions Directed By Phrasal Structures

In such a society as now with exploding information, processing naturallanguages becomes more and more necessary. In contrast to traditional methods, wedo not guest the content of natural language texts with statistical methods, but withdefinitely computing methods;not study how to say,but what to say;not explore thedeep meaning, but the literal meaning. In short, we definitely compute what to be saidliterally in a natural language text.To achieve this goal, we need to analyze what entities and what relations to besaid in a text, and how they are organized. however, some researchers focus purely onthe syntactic relations, but ignore the literal meaning;some researchers are consciousof the importance of studing the literal meaning,but are lack of a deep understandingof it;some researchers see that the entities and relations and the organization of themcan be described by semantic types and semantic nets,but they don't provide anycorresponding intact computing theory of semantic types and any mechanicallyconstructiong method of semantic nets,.....To overcome the shortcomings above, we provide the theory of computation ofcategorical expressions directed by phrasal structures. This theory uses hierarchialmethod to describe and interpret language phenomena.The phrasal structures in thesyntactic layer provide relevant information to help th computing of categorialexpressions and the constructing of semantic nets;Based on the basic semantic types,categorial expressions describe the entities, relations and the organization ofthem.What's more, the organization of entities and relations can be built by thecomputing of categorial expressions;On the base of the computing of categorialexpressions,we study the mechanical constructing method of semantic nets.The following is the major contents of this dissertation:(1)The definition of generalized categorial expressions.The order of words, theequation of sentence components, the mode of language, the transformation oflanguage, the coordination and so on are all the phenonema concerned by linguistsand computational linguists. Based on the basic semantic type hierarchy, thedefinition of generalized categorial expressions is given step by step to describe andinterpret these phenomena.(2)The computing of categorial expressions. Categorial expressions are stricterand abstracter than generalized categorial expressions.We formalize a categorialexpression as a directed acyclic graph and difine the reduction and unificationcalculus of categorial expressions.(3)The definition and mechanical construction of semantic net.A semantic net isa graph composed of nodes and edges. We study the principles of constuctingsemantic nets and and provide the mechanical method of constructing static semanticnets and dynamic semantic nets.(4)The tagging of words and rules and the investigation of languagephenomena.Words and rules are the base of the theory of computing categorialexpressions directed by phrasal structres. We study the form and method of taggingthe pronouns, nouns, verbs, adjectives and so on. During investigating the commontypical languange phenomena, the tagging method of rules is studied. It is proved thetheory is strong in interpretting ability and feasible in practice.(5)The investigation of ambiguities and semantic orientions.There areambiguities in some sentences. The semantic orientions of the components of asentence may not correspond to its syntactic structure.It is difficult for linguistists andcomputational linguistist to interpret those phenomena. The theory of computation ofcategorial expressions directed by phrasal structures provides new way to decomposeand cut ambiguities and determine the semantic oriention.