Week 12

Decision tree: is also a knowledge codification technique. A decision tree is usually a hierarchically arranged semantic network.

Frame: A frame is a codification scheme used for organizing knowledge through previous experience. It deals with a combination of declarative and operational knowledge. Key elements of frames:

      Slot: A specific object being described/an attribute of an entity.

     Facet: The value of an object/slot.

Production Rule: They are conditional statements specifying an action to be taken in case a certain condition is true. They codify knowledge in the form of premise-action pairs.

Syntax: IF (premise) THEN (action)

Rules can incorporate certain levels of uncertainty. A certainty factor is synonymous with a confidence level, which is a subjective quantification of an expert's judgment. The premise is a Boolean expression that should evaluate to be true for the rule to be applied. The action part of the rule is separated from the premise by the keyword THEN. The action clause consists of a statement or a series of statements separated by AND's or comma's and is executed if the premise is true.

In case of knowledge-based systems, planning involves:

• Breaking the entire system into manageable modules.
• Considering partial solutions and liking them through rules and procedures to arrive at a final solution.
• Deciding on the programming languages.
• Deciding on the software packages.
• Testing and validating the system.
• Developing the user interface.
• Promoting clarity, flexibility; making rules clear.
• Reducing unnecessary risk.

Role of inference:

• Inference implies the process of deriving a conclusion based on statements that only imply that conclusion.
• An inference engine is a program that manages the inference strategies.
• Reasoning is the process of applying knowledge to arrive at the conclusion.

Case-Based Reasoning: Case-based reasoning is a technique that records and documents cases and then searches the appropriate cases to determine their usefulness in solving new cases presented to the expert. The aim is to bring up the most similar historical case that matches the present case. Adding new cases and reclassifying the case library usually expands knowledge. A case library may require considerable database storage as well as an efficient retrieval system.

Knowledge-Based Agents: An intelligent agent is a program code which is able to perform independent action in a appropriate manner. They can exhibit goal directed behavior by taking initiative. They can be programmed to interact with other agents or humans by using some agent communication language. In terms of knowledge-based systems, an agent can be programmed to learn from the user behavior and deduce future behavior for assisting the user.

Kulsum Raza