Cost-optimal and Net-benefit Planning : A Parameterised Complexity View

Cost-optimal planning (COP) uses action costs and asks for a minimum-cost plan. It is sometimes assumed that there is no harm in using actions with zero cost or rational cost. Classical complexity analysis does not contradict this assumption; planning is PSPACE-complete regardless of whether action costs are positive or non-negative, integer or rational. We thus apply parameterised complexity analysis to shed more light on this issue. Our main results are the following. COP is W[2]-complete for positive integer costs, i.e. it is no harder than finding a minimum-length plan, but it is para-NPhard if the costs are non-negative integers or positive rationals. This is a very strong indication that the latter cases are substantially harder. Net-benefit planning (NBP) additionally assigns goal utilities and asks for a plan with maximum difference between its utility and its cost. NBP is para-NP-hard even when action costs and utilities are positive integers, suggesting that it is harder than COP. In addition, we also analyse a large number of subclasses, using both the PUBS restrictions and restricting the number of preconditions and effects

最良優先探索のための探索非局在化手法

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 Fukunaga Alex, 東京大学教授 山口 和紀, 東京大学准教授 田中 哲朗, 東京大学准教授 金子 知適, 東京大学准教授 森畑 明昌University of Tokyo(東京大学