We tackle the challenge brought to urban library systems by the {holds system} -- which allows users to request books available at other branches to be transferred for local pickup. The holds system increases usage of the entire collection, at the expense of an in-person browser's experience at the source branch. We study the optimization of usage and browser experience, where the library has two levers: where a book should come from when a hold request is placed, and how many book copies at each branch should be available through the holds system versus reserved for browsers. We first show that the problem of maximizing usage can be viewed through the lens of revenue management, for which near-optimal fulfillment policies exist. We then develop a simulation framework that further optimizes for browser experience, through book reservations. We empirically apply our methods to data from the New York Public Library to design implementable policies. We find that though a substantial trade-off exists between these two desiderata, a balanced policy can improve browser experience over the historical policy without significantly sacrificing usage. Because browser usage is more prevalent among branches in low-income areas, this policy further increases system-wide equity: notably, for branches in the 25% lowest-income neighborhoods, it improves both usage and browser experience by about 15%.

翻译：我们研究了城市图书馆系统面临的"预约系统"挑战——该系统允许用户预约其他分馆的图书并调至本地分馆取书。预约系统虽能提升整体馆藏利用率，却以牺牲源分馆现场浏览者的体验为代价。本文探讨使用率与浏览体验的优化问题，图书馆可通过两个调控杠杆实现优化：处理预约请求时如何选择图书来源分馆，以及各分馆应分配多少副本用于预约系统、多少副本保留给现场浏览者。首先，我们证明最大化使用率问题可纳入收益管理理论框架，该框架下存在近似最优的履约策略。随后，我们开发了通过图书预留机制进一步优化浏览体验的仿真框架。基于纽约公共图书馆的实际数据，我们实证应用该方法设计可实施策略。研究发现：尽管两个目标之间存在显著权衡，但平衡性策略能在不明显牺牲使用率的前提下，较历史策略显著改善浏览体验。由于低收入区域分馆的现场浏览使用更为普遍，该策略进一步提升了系统整体公平性：值得注意的是，对于收入最低的25%社区分馆，该策略使使用率和浏览体验均提升约15%。