Chapter 12. DECISION RULES AND EXPRESSIONS. 12.1 Introduction. Decision rules often are represented in one of two formats Procedures Production rules. 12.2 PROCEDURAL KNOWLEDGE. Two key features characterize this representation
FIGURE 12-1 Decision rule represented as a decision tree. The decision rule helps determine the diagnosis in a case of a patient with a sore throat based on physical examination findings.
FIGURE 12-2 Decision rule represented as production rules. This collection of production rules represents the same knowledge as the decision tree in Figure 12-1. Each rule associates a Boolean condition that evaluates to true or false with an action (in this case, a diagnosis). The terms “erythema,”“pus,” and “adenopathy” are Boolean variables that evaluate to true or false based on data available to the CDSS.
FIGURE 12-5 procedural representationExample of GELLO encoding a simple guideline. This guideline rep resents the same knowledge contained in the Arden Syntax MLM in Figure 12-4. Because GELLO was created to extract data from clinical repositories, to manipulate those data and to reason over them, it does not have an explicit syntax for sending messages to clinicians. The CELLO code would he embedded in complete guideline representation or other application for use by the CDSS.