利用算符分析的问题求解

PROBLEM SOLVING THROUGH OPERATOR ANALYSIS

将状态空间的问题求解过程变换为逐步缩小与目标状态的差异过程是一种问题的分解方式．求解差异的顺序可通过分析算符对状态的影响而作出规划，规划的原则是最大限度地在不改变最近已实现子目标的条件下实现下一子目标．为此，在问题分解时各层子目标选择的依据是让各算符有最大的可利用率，即以状态对算符最小约束传播的原则选择各层子目标；最后生成一个子目标规划层次集．问题求解过程就表现为从初始状态开始实现层次集中的某一子目标序列，其间可能涉及子目标回溯．

olving Problems through serially removing differences is a kind of problem decomposition. The order of differences to be removed can be planned based on the analysis of operators. The main idea of this plan is to attain next subgoal without undoing the last attained subgoal. Thus, during problem decomposition, those subgoals which keep the operators most usable are chosen, some what like the least constraint propagation.When a set of hierarchic subgoals is generated, the search of initial problem is to attain a serial of subgoals in the set, during which backtracking may happen.