Abstract: The demand for relief supplies after the sudden strike of disasters is growing at an explosive rate. Sufficient relief supplies play a vital role in guaranteeing the post-disaster relief effect and reducing economic losses. The governments, as central organizations against disasters, usually entrust one or more enterprises to reserve relief supplies prior to disasters. Once a sudden disaster occurs, those prepositioned relief supplies are immediately allocated to disaster-affected areas as soon as possible. However, in practice, the enterprises are prone to moral hazard such as laziness and slackness, because of the incomplete contract, the differences of targets, and the asymmetry of information between the governments and the enterprises. Therefore, it is difficult to guarantee adequate and available relief supplies in hand. This paper introduced the reputation effect mechanism into the prepositioning system of relief supplies, which consisted of a single government and two enterprises. It established a dynamic incentive model for the prepositioning system of relief supplies, and derived the optimal punishment-reward coefficient of the government and the optimal effort level of the enterprises. It also gave the condition for the reputation effect mechanism to play a long-term incentive role. The results show that the proposed dynamic incentive model not only improves the optimal effort level of the enterprises, but also realizes Pareto improvement of the members in the supply chain system of relief supplies under a certain condition when compared with the static incentive model. It also reduces the possibility of the moral hazard of the enterprises and is conducive to maintaining the long-term and stable cooperative relationship between the government and the enterprises.

Key words: pre-positioning of relief supplies, dynamic incentive model, reputation effect, principal-agent theory

摘要： 突发灾害发生后，应急物资需求量呈现爆发式增长，充足的应急物资对于保障灾后救援效果以及减少经济损失具有重要作用。通常情况下，政府在灾前委托一个或多家企业储备应急物资，一旦突发灾害发生，立即调拨所需物资至受灾区。但在实际情况下，由于政企合作契约的不完备及政企目标的差异与信息的不对称，企业很容易出现偷懒、消极怠工等道德风险，突发灾害发生时很难保障充足可用的应急物资。为此，在政企委托代理关系的基础上，引入声誉效应机制到政府和两个企业组成的应急物资储备系统，构建了考虑声誉效应的应急物资储备系统动态激励模型，求解了政企多期合作下政府最优奖惩系数和企业最优努力水平，给出了声誉效应机制发挥长期激励作用的条件。与不考虑声誉效应的应急物资储备系统激励模型相比，在一定条件下考虑声誉效应的应急物资储备系统动态激励模型可以提高企业努力水平，实现了供应链系统成员收益帕累托改善，降低了企业出现道德风险的可能性，有利于维护政企之间长久稳定的合作关系。

关键词: 应急物资储备, 动态激励模型, 声誉效应, 委托代理理论