Information Systems Reengineering, Integration and Normalization - Information Systems Reengineering, Integration and Normalization - page 6

User Interface

Main Processing
System

Database
Management
System

Model-base
Management
System

Standard
Supporting Tools

Database Model-base

Fig. 1.2 Fundamental structure of decision support system (DSS)

1.1.10 Expert Systems (ESs)

ESs have been widely used in our society from technical and medical to financial,
teaching, and administrative applications. They are a general term for special soft-
ware systems that preserve the knowledge of human experts and reason with it. The
basic differences between ESs and conventional software systems are:

• Conventionalsoftwaresystems are algorithmic. They produce unique and cer-
tain answers, e.g., yes or no.
• ESs,bytheirnature,areheuristic. The results that they produce are not always
unique, nor are they necessarily certain and correct, e.g., yes, no, or unknown.

In the recent years, ESs have played an important role in information systems. Their
technologies have been used in the more advanced information systems, such as
executive information systems (EIS) and executive support systems (ESS). The
purpose of EISs is to assist high-level managers with either information or knowl-
edge relating to an organization's decision processing. Most current EISs gener-
ate decision knowledge for an organization by integrating ESs with databases. The
technical term for this type of systems is called expert database systems (EDS). The
ESS often combines DSS and MIS capabilities. ESs usually are the kernel of these
types of systems.