certainty factor a numeric measure of the degree of belief in a proposition. In EMYCIN, the CF ranges from -1 (false) to 1 (true).
character macro in Lisp, a macro that is invoked by a single character in the source code.
[edit] Certainty factors
The MYCIN rule-based expert system introduced a quasi-probabilistic approach called certainty factors, whose rationale is explained below.
MYCIN's Certainty Factors
Uncertainty in Rule-Based Systems. See Chs 10-13 of the book on experiments with the Mycin system.
3.6 Certainty factors theory and evidential reasoning 74
3.7 FORECAST: an application of certainty factors 80
3.8 Comparison of Bayesian reasoning and certainty factors 82 ...
Originally we attached probabilistic weights -- that is, numerical certainty factors -- to each sentence we gave CYC.
uncertainty_rule d_1 if input1 is not high and input2 is not high then output is high with certainty factor -0.9 . uncertainty_rule d_2 if input1 is not high and input2 is high then output is high with certainty factor 0.1 .
Second, the rules had to reflect the uncertainty called certainty factors which seemed (at the time) to fit well with how doctors assessed the impact of evidence on the diagnosis ' (Russel & Norvig, 2003).
 See also: Expert system, Knowledge, Artificial intelligence, Inference, AI
  
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