Computer Science 431

Exam #2 review:

Disclaimer: I have attempted to be comprehensive in the following, but important items may have been omitted by mistake. If you see such an omission, please let me know, but you are responsible for all of the lecture material to date.

The second hour exam will be on Thursday, Nov. 7, and will cover

Textbook:  Chapters  4 and 6, including material on resolution in the propositional calculus, more in-depth material on searching (A* search),

Course Notes:  KRSurvey.ppt, Lisp02.ppt

(NEW) Newell and Simon paper

• Be able to describe the role of heuristics in search, and to describe in some detail the workings of A* search..
• Be able to write basic algorithms (in lisp) for  A* search. I will not give you a problem that involves printing out a path - only the very basic search algorithms will be explored (so most of the machinery in the homework programs can be tossed out).
• Be able to write expressions in the propositional calculus, construct truth-tables, distinguish between valid, satisfiable, and unsatisfiable, and do resolution theorem proving in the propositional calculus. Know the basic identities and definitions (contrapositive, necessary condition, etc.)
• Be able to describe the basic knowledge representation schemes.
  • Slot and filler structures: Be able to describe "weak" slot-and-filler structures (such as the deftemplate in CLIPS and the "strong" slot-and-filler structures (such as scripts)
  • network structures: including "ISA" hierarchies (default reasoning) and semantic networks (there is some additional information on the SNePS home page).
  • productions: CLIPS would serve as a good example
  • logic: including the propositional calculus we have already started to study. Material on the predicate calculus will be on the next exam (after we have spent some more time with it).
• Be able to give a general description of rule-based expert systems.
• Be able to write simple templates and rules in CLIPS.  Be able to print things out and assert facts (including those contained in initial-facts).  Because we are still working on a programming problem, the material on CLIPS will be limited to the level of those things done in class.
• (NEW) Be able to describe the physical symbol system hypothesis and explain what it means.  Be able to discuss the role of search in the physical symbol system hypothesis.

Any questions?  Please ask!

-Bob