The Generalized Production Rule System (GPRS)

Abstract

In decision making, a fairly precise knowledge of the values of all relevant situational variables is necessary. We call open variables (OVs) those that can be observed and measured at any space and time point while the values of hidden variables (HVs) can be obtained only intermittently, at certain points of space and time. The following examples should clarify this issue:

• Atmospheric conditions. The OVs are measured continuously at the Earth’s surface whereas high-altitude variables, such as stratospheric wind velocity and air temperature, are HVs and can be observed only when, for example, balloon-borne instruments and a radio transmitter are sent up to the “right” altitude and location.

• Material testing. Inexpensive and non-destructive testing of some material or product can be performed at any desired time but costly or destructive tests are carried out only sparingly.

• Oil and mineral exploration. The evaluation of satellite photographs, seismic experiments, geological surface studies and deep-drill work can produce OVs or HVs, depending on the associated factors of cost and difficulty.

• Earthquake prediction. In addition to seismographical data, a number of different OVs have been proposed and used that are likely to be correlated with the near-future occurrence of earthquakes. The HVs can be, for example, the location of the epicenter and the intensity of an earthquake to come.

• The training of specialists. The (controlled) OVs may be the length and intensity of training or the frequency of given exercises, while the level of actual performance under certain rare conditions represents an HV.