해빙 위험도와 시간ㆍ비용을 고려한 강화학습 기반 북극항로 다목적 최적화
The Northern Sea Route (NSR), increasingly navigable as Arctic sea ice retreats, can substantially shorten shipping distance, but route planning is difficult because navigability and risk at a location depend on a ship's arrival time. In practice it is rarely a single-route problem: forecasts are uncertain and frequently updated, and operators must weigh many departure times and time-cost trade-offs, so a planner is queried repeatedly. Graph-search and metaheuristic methods recompute a full solution per query and become the bottleneck, while prior reinforcement learning studies on Arctic routes assume static ice and ignore arrival-time-dependent risk. This study proposes a framework in which ST-A* (Space-Time A*) generates demonstration trajectories for different time-cost weights, and DQfD (Deep Q-Learning from Demonstrations) uses them to learn weight-specific policies that produce routes for new ice conditions by inference, without the full space-time re-search. On 51 unseen test cases from 2023-2025, the learned policies reached the destination in every case with lower objective values than a baseline trained without demonstrations. Relative to ST-A*, they produced routes about 700 times faster at a mean objective 1.57 times higher, a bounded loss in per-route optimality that makes large numbers of route evaluations tractable.