The general objective of this thesis is the development of an adaptive technique for extracting knowledge in large databases. Nowadays, technology allows storing huge volumes of information. For this reason, the availability of techniques that allow, as a first stage,…

The aim of this work is to relate two apparently independent concepts as belief revision and relevance. We propose a formal characterization for the notion of (ir)relevance by means of a set of postulates. Then we define (ir)relevance using change…

There exists a large amount of knowledge representation models. But most of them have significant limitations at the epistemic level. They do not have explanatory power. Most of them do not have means to represent some functional needs to work…

Fish disease diagnosis is a complicated process and requires high level of expertise, an expert system for fish disease diagnosis is considered as an effective tool to help fish farmers. However, many farmers have no computers and are not able…

To find a good termination criterion for genetic algorithms is a difficult and frequently ignored task. In most instances the practitioner stops the algorittm after a predefined number of generations or function evaluations. How this number is established? This stop…

The development of isolated agents involves the manipulation of components such as actions, mental attitudes and decisions. Multi-agent systems have to deal with these components from different agents, without to forget the privacy and autonomy of each agent. For programming…

The development of systems with the ability to reason about change notion and actions has been of great importance for the artificial intelligence community. The definition and implementation of systems capable of managing defeasible, incomplete, unreliable, or uncertain information has…

We identify different kinds of relevance relations between formulas that emerge in the process of belief revision. Informal definitions for alternative notions of relevance are suggested and a set of schemas and intuitive postulates for formalizing these notions are proposed.

Classical methods for representing and reasoning with knowledge rely on the assumption that the available information is complete, certain and consistent. In real-world problems this is usually not the case, and Al has long dealt with the issue of finding…

Most unsupervised indigenous knowledge (IK) are known to be very useful in combating critical health issues as well as being dangerous if the administration is abused. Despite the fact that these locally prepared herbal medicine are not encouraged to be…