Frame Based System

FRAME BASED SYSTEM Frame-based systems are knowledge representation systems that use frames, as their primary means to represent domain knowledge. Knowledge is organized in the form of chunks called frames. These frames are supposed to capture the essence of concepts or stereotypical situations. For example, being in a living room or going out for dinner, by clustering all relevant information for these situations together. Frames includes information about how to use the frame, information about expectations (which may turn out to be wrong), and information about what to do if expectations are not confirmed, and so on. Collections of such frames are to be organized in frame systems in which the frames are interconnected. Features 1. Frames are organized in (tangled) hierarchies; 2. Frames are composed out of slots (attributes) for which fillers (scalar values, references

to other frames or procedures) have to be specified or computed; and 3. Properties (fillers, restriction on fillers, etc.) are inherited from superframes to subframes in the hierarchy according to some inheritance strategy. One of the most important reasoning tasks in this context is the determination of subsumption between two concepts, that is, determining whether all instances of one concept are necessarily instances of the other concept taking into account the definitions. For example, "Grandmother" is subsumed by "Parent" because everything that is a "Grandmother" is -- by definition -- also a "Parent." Similar to the subsumption task is the instance-checking task, where one wants to know if a given object is an instance of the specified concept.

Thematic Role Frames Semantic analysis uses so-called thematic-role frames to capture detailed knowledge about how acts happen. Thematic-role frames describe the action conveyed by the verbs and nouns appearing in typical declarative sentences. Much of what happens in the world involves actions, and objects undergoing change. It is natural, therefore, that many sentences in human language amount to descriptions that specify actions, identify the object undergoing change, and indicate which other objects are involved in the change.

A sample thematic role frame is given by:

THEMATIC OBJECT: The argument of a verb which is realized in object position. In ergative predicates the thematic object is not assigned case by the verb and must therefore raise to spec-IP to be assigned nominative case. Themes are typical thematic objects. For ex, in John likes Mary, the thematic object of like is ‘Mary’. A verb is a word (part of speech) that usually denotes an action, an occurrence, or a state of being. Depending on the language, a verb may vary in form according to many factors, possibly including its tense, aspect, mood and voice. An agent is either: an entity who is capable of action or someone (or something) who acts on behalf of another person. A beneficiary is a natural person or other legal entity who receives money or other benefits from a benefactor. For example: The beneficiary of a life insurance policy, is the person who receives the payment of the amount of insurance after the death of the insured. Trajectory is the solution to a dynamical system in forward and backward time passing through a specified initial condition.