This paper proposes a novel parcel delivery system which consists of a drone and public transportation vehicles such as trains, trams, etc. This system involves two delivery schemes: drone-direct scheme referring to delivering to a customer by a drone directly and drone-vehicle collaborating scheme referring to delivering a customer based on the collaboration of a drone and public transportation vehicles. The fundamental characteristics including the delivery time, energy consumption and battery recharging are modelled, based on which a time-dependent scheduling problem for a single drone is formulated. It is shown to be NP-complete and a dynamic programming-based exact algorithm is presented. Since its computational complexity is exponential with respect to the number of customers, a sub-optimal algorithm is further developed. This algorithm accounts the time for delivery and recharging, and it first schedules the customer which leads to the earliest return. Its computational complexity is also discussed. Moreover, extensive computer simulations are conducted to demonstrate the scheduling performance of the proposed algorithms and the impacts of several key system parameters are investigated.

中文翻译：

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包含与公共交通工具互动的空中无人机的包裹递送系统的计划。

本文提出了一种新颖的包裹交付系统，该系统由无人驾驶飞机和诸如火车，电车等公共交通工具组成。该系统涉及两种交付方案：无人驾驶飞机直接交付方案，是指由无人驾驶飞机直接交付给客户和无人驾驶汽车。协作方案是指基于无人机和公共交通工具的协作来交付客户。对包括交付时间，能源消耗和电池充电在内的基本特征进行了建模，在此基础上制定了单个无人机的时间相关调度问题。它被证明是NP完全的，并且提出了一种基于动态编程的精确算法。由于其计算复杂度与客户数量成指数关系，因此进一步开发了次优算法。该算法考虑了交货和充电的时间，它首先计划了导致最早退货的客户。还讨论了其计算复杂性。此外，进行了广泛的计算机仿真，以证明所提出算法的调度性能，并研究了几个关键系统参数的影响。