Artificial Intelligence and Soft Computing: Behavioral ... - Arteimi.info

control of data and knowledge is unique, depending on their position in the
program.
21.4.4 Maintaining Security in Knowledge
Based Systems
‘Security’ [5], like other software, is equally useful in expert systems. It
prevents unauthentic use / change of system resources. For instance, if there is
no password check, anyone can change the knowledge base. A clever
programmer may also affect the inference engine. Thus while updating
knowledge, maintaining the security is a fundamental requirement in expert
systems technology.
21.5 Conclusions
Performance evaluation of knowledge base systems is a fundamental issue of
knowledge management. In this chapter we discuss different means for
verifying the knowledge base. The key issues of knowledge verification are to
keep the knowledge base free from incompleteness and inconsistency. For
verifying non-monotonic systems the most important issue is to rank the level
of the ab predicates in the same knowledge base. In my opinion, here the
binary logic fails to yield a stable inference. In fact, multi-level logic may be
used to overcome this difficulty of non-monotonic systems. Currently, special
emphasis is given on the maintenance of the knowledge-based systems. This
is useful as every year around 800-1000 new pieces of knowledge [7] are
being added to expert systems. While augmenting the knowledge base,
checking for inconsistency should be carried out to keep the system running
smoothly over several years. Security of knowledge based systems should
also be maintained to prohibit the unauthorized access to the system
resources.
Exercises
1. Given the following knowledge base R, determine which of the rules in
set R is dangling. R = {IF A, B THEN C, IF C THEN D}, Database =
{A, C}.
2. Which is the useless conclusion in problem 1? Is there any isolated rule in
the above system?
3. Determine the type of inconsistencies in the following knowledge bases
(KB)