Artificial Intelligence2

Artificial Intelligence

Attribute and Value:

An attribute is a word, phrase, or symbol that names or stands for something. Examples are cell_mass, aeration_rate, Bioreactor_Number_7, foreman, name_of_foreman, George, etc. Note that these are labels and that it makes no difference if we abbreviate or complicate the label. The lines that link words are simply good computer practice because some programs would take a space as a delineator. A value is a characteristic for an attribute. For example, full could be the value for Bioreactor_Number_7. There are several ways to express a value - as a word, a number, or as a logic state (truth or false). We can often parse sentences into attributes and values as in the following:

Sentence <---------------> Attribute <---------> Value

The temperature is 81. <-----> Temperature <------> 81

You are a liar. <------------> Your_statement <--> false

George is tall and fat. <------> George <---------> fat tall

Reactor is contaminated. <----> Contaminated <----> true

A problem arises when the value has not been assigned. In a system where one stands for true and zero stands for false, using zero for a value makes it look as if the value is known and assigned. We could leave the value blank, but the computer might take this as a zero. The AI people use a special variable nil that means no value or value not assigned. This terminology is straightforward and is unlikely to cause problems. One thing to watch for in complicated systems is labeling the same thing two different ways. Unless the computer program accounts for labels that are equivalent, an attribute that is supposedly unique will be confused with the other label.

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Last update: 7-Dec-94, comments to cockbd@rpi.edu and patand@rpi.edu