Handling temporal constraints with preferences in HTN planning for emergency decision-making

Article type: Research Article

Authors: Li, Minglei^{a; b; c} | Wang, Hongwei^{a; b; c; *} | Qi, Chao^{a; b; c} | Zhou, Chao^{a; b; c}

Affiliations: [a] School of Automation, Huazhong University of Science and Technology, Wuhan, China | [b] Key Laboratory of Education Ministry of Image Processing and Intelligent Control, Huazhong University of Science and Technology, Wuhan, China | [c] Hubei Collaborative Innovation Center for Early Warning and Emergency Response Technology, Wuhan, China

Correspondence: [*] Corresponding author. Hongwei Wang. Tel./Fax: +86 027 87540084; E-mail: [email protected].

Abstract: HTN (Hierarchical Task Network) planning has shown its effectiveness and potential in emergency decision-making. In realistic emergency conditions, the temporal preferences should be considered. This paper proposes a temporal HTN planner, TPHTN (Temporal Preferences HTN), to handle the temporal constraints with preferences. The planner uses STNP (Simple Temporal Networks with Preferences) to express the temporal preferences information, and extends the operator and method to express the temporal preferences information in planning domain knowledge. In the planning process, TPHTN propagates the STNP top-down, and three definitions of level consistency are proposed to estimate the quality of STNP, and a new heuristic search is designed to choose the suitable operator/method to apply based on the quality of the corresponding STNP. When the planning process is terminated, TPHTN will generate a plan satisfying the decision-makers preferences. Finally, the effectiveness and practicability of TPHTN are demonstrated with emergency logistics problems.

Keywords: HTN planning, temporal constraints with preferences, heuristic search, emergency decision-making

DOI: 10.3233/IFS-151899

Journal: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 4, pp. 1881-1891, 2016