Expressing Concern

A consultant system's main task is to provided helpful advice to the user. Consultant systems should not only find solutions to user problems, but should also inform the user of potential problems with these solutions. Expressing such potential caveats is a difficult process due to the many potential plan failures for each particular plan in a particular planning situation. A commonsense planner, called KIP, Knowledge Intensive Planner, is described. KIP is the planner for the UNIX Consultant system. KIP detect potential plan failures using a new knowledge structure termed a concern. Concerns allow KIP to detects plan failures due to unsatisfied conditions or goal conflict. KIP's concern algorithm also is able to provide information to the expression mechanism regarding potential plan failures. Concern information is passed to the expression mechanism when KIP's selected plan might not work. In this case, KIP passes information regarding both the suggested plan and the potential caveats in that plan to the expression mechanism. This is an efficient approach since KIP must make such decisions in the context of its planning process. A concern's declarative structure makes it easier to express than procedural descriptions of plan failures used by earlier systems. Marc Luria Computer Science Department Technion, Israel Institute of Technology Halfa Israel (a2) Let me know if the door is locked. (a3) Be careful walking down the stairs. (a4) Make sure to turn off the basement light. In (al), the mother has provided the child with information about the location of his shoe. The mother has also implied the use of a plan: Walk down to the basement and get your shoes. However, there are a number of problems inherent in this plan. The mother might also inform her child of these problems. The first problem, (a2), is that one of the conditions necessary to execute the plan might be unsatisfied. The door to the basement might be locked. If it is locked additional steps in the plan will be necessary. The second problem, (a3), is that executing the walk-down-the-stairs plan might result in a fall. The mother knows that this outcome is likely, due to her experience of the child's previous attempts at the walk-down-the-stairs plan. The mother wishes to prevent the child from falling, since this is a potentially dangerous and frightening experience for the child. The third problem, (a4), is that the child might forget to turn off the light in the basement. This would threaten the mothers's goal of preventing the basement light from burning out. However, the same parent might not add: