# Basic Concepts

In this section, we present the basic concepts that you need to understand to use the HUGIN System. These concepts are Bayesian belief networks and influence diagrams.

The Paradigms of expert systems is a translation of a lecture note used in an introductory course on decision support systems at Aalborg University. It gives a brief overview of rule based systems, neural networks and Bayesian belief networks, and a comparison of these.

In the introduction to Bayesian belief networks, the concept of Bayesian belief networks is presented through a small example. This is done in general terms and does not consider how the network is implemented in HUGIN. In the introduction to influence diagrams the concept of influence diagrams is presented the same way.

You can also read a more detailed description of the Bayesian belief network technology used in HUGIN. Here, the concept of Bayesian belief networks with continuous nodes is presented. This section is only meant for people with a mathematical background.

Back