Knowledge Representation and Validation in a Decision Support System: Introducing a Variability Modelling Technique - Efficient Decision Support Systems: Practice and Challenges from Current to Future - page 34

Fig. 1. Variability in Reward System: Upper layer representation
3.1.1 Upper layer representation of the proposed method (FM-OVM)
In this layer, we combined FM diagram with OVM notations. Figure 1 represents the upper
layer of our proposed method. Optional and mandatory constraints are defined in Figure 1
by original FM notations [9], and constraint dependency rules are described using OVM
notations. OVM and FM can easily become very complex for validating a medium size
system, i.e., several thousands of decision points and choices are needed. This reason
motivates us to develop an intelligent method for representing and validating variability in
DSS.
3.1.2 Lower layer of the proposed method
Decision points, choices, and constraint dependency rules are used to describe variability
[20]. Constraint dependency rules are: decision point requires or excludes decision point,
choice requires or excludes choice, and choice requires or excludes decision point. In this
sub-section, decision points, choices, and dependency constraint rules are described using
predicates as a low level of the proposed method. Examples are based on Figure 1. Terms
beginning with capital letters represent variables and terms beginning with lower letter
represent constants. Table 2 shows the representation of Negative Performance decision point
using the lower layer of the proposed method.