Stereotypes: As an actor approach towards solving the problem of procedural attachment in frame theories

Abstract

This paper is a spin-off of our work on actors. We have worked out a dictionary for translating between what Minsky et.al, are saying about frames and what we are saying about actors. Using PLASMA [PLANNER-like System Modeled on Actors].we can demonstrate important relationships between the Minsky-frames and the PLANNER-like formalisms. PLASMA does not use the Q A-4 context mechanism (Rulifson et. al. 1972): instead It uses explicit tags in assertions to keep track of the state of affairs in various situations. One problem with the QA-4 context mechanism is that the problem solver is forced to attempt to propagate all changes in the situation immediately on a frame shift since otherwise inconsistent information will be inherited from the previoussituation. Another problem with Q A-4 context meclhanism is that it is sometimes difficult to reason explicitly about various Situations using it because situations [frames] are not explicitly part of the assertions and goals. Events that are Viewed from several different viewpoints [as in a murder mystery] are difficult to handle. Also It Is difficult to retrieve the appropriate prior situations from memory to aid In recognition tasks using Q A-4 contexts. However, without the example of the QA-4 contexts to guide us, we could never have realized holy to deal with these, problems using' tagged assertions. The context mechanism in' CONNIVER was modeled on the one in QA-4.