Disjunction

In general, both the preconditions and conclusions can have conjunctions (AND), disjunctions (OR), and negations (NOT). Conjunctions make a rule more specific, whereas disjunctions make a rule more general. A rule with a disjunction is equivalent to two separate rules with the same conclusion. 

Thus certainty factors express the intuitive notion that the certainty of a conclusion should be lower than the certainty of the data and knowledge involved in arriving at the conclusion. Certainty factor theory also allows for combining the CFs of conjunctions, disjunctions, and negations ... 

To illustrate the power of the object-oriented style of representation, consider the reactor diagnosis example used eadier in the discussion of rules. Assume that there are several reactors, R-101, R-102, etc, each served by a common cooling system. Relating coolant malfunctions to the temperature in each reactor would need multiple rules, or rules with multiple disjunctions. Instead, if rules are used in combination with the object representation described above, a single general rule can be written to cover all the specific instances, as follows. 

Selection 3 from the FTAPSUIT menu (Figure 6.4-3) runs FTAPlus to prepare input for the postprocessor (Figure 6.4-5). To print the contents of the block file, the postprocessor input must contain either the command PRTDNF or FRMBLK (selections 2 and 3 respectively). The command PRTDNF (print equation in disjunctive normal form) allows you to display the contents of a punch file in readable form. FRMBLK (form block) is required to generate an FTAP input file. The... 

A logical clause is a disjunction of terms, and a horn clause is one where, at most, one term is positive. In propositional logic, where only literals are allowed horn clauses have the following form ... 

A study of Cladonia cervicornis (Achar.) Flotow from two widely disjunct populations in California, one from coastal Mendocino County and one from the foothills of the Sierra Nevada in Amador County, revealed a difference in the frequency of occurrence of the depside atranorin [245] (see Fig. 2.76) (Hammer and Ahti, 1990). The compound, considered to be a primitive feature of this lichen species, was present in 80% of the... 

Some years ago, Breckon and Barbour (1974) published a review of beach vegetation for the North American Pacihc Coast that contains detailed information on a wide variety of strand taxa. A number of taxa discussed in their work have disjunct distributions, involving other continental beaches suggesting other taxa worthy of detailed phytogeographic study. 

The availability of North American specimens of Glehnia made it possible to compare coumarin and acetylene profiles of this widely disjunct system (Hiraoka et al., 2002). Analysis of plant material collected from four widely separated sites, that is, northern California, central Oregon, northern Washington, and northeastern Queen Charlotte Islands, British Columbia, revealed a profile characterized by low levels of furanocoumarins and a comparatively high level of panaxynol. The results are similar to those that characterize the southern Japanese form. The North American... 

Table 4.4 Flavonoid profiles of the disjunct species of Tiarella (from Soltis and Bohm, 1984)...

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