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Gleaning programs organize volunteer gleaners to harvest a variety of leftover crops that are donated by farmers for the purpose of feeding food-insecure individuals. Thus, the gleaning process simultaneously reduces food waste and food insecurity. However, the operationalization of this process is challenging because gleaning relies on two uncertain sources of input: the food and labor supplies. The purpose of this paper is to help gleaning organizations increase the (value-weighted) volume of fresh food gleaned by better managing the uncertainties in the gleaning operation. We develop a model to capture the uncertainties in food and labor supplies and seek a dynamic volunteer-staffing policy that maximizes the payoff associated with the amount of food gleaned. The exact analysis of the staffing problem seems intractable. Therefore, we resort to an approximation in the heavy traffic regime. In that regime, we characterize the system dynamics of the multicrop gleaning operation and derive the optimal staffing policy in closed form. The optimal policy is a nested threshold policy that specifies the staffing level for each class of donation (i.e., a donation of a particular crop type and donation size). The policy depends on the number of available gleaners and the backlog of gleaning donations. A numerical study using data calibrated from a gleaning organization in the Boston area shows that the dynamic staffing policy we propose can recover approximately 10% of the volume lost when the gleaning organization uses a static policy. To achieve this improvement, no capital or major process changes would be required--only some small changes to the staffing level requests. History: An earlier version of this paper was circulated with the title 'Dynamic Staffing of Volunteer Gleaning Operations' and is available from SSRN: https://ssrn.com/abstract=2873250 or http://dx.doi.org/10.2139/ssrn.2873250. Funding: This work is supported by the Neubauer Family Foundation at the University of Chicago Booth School of Business. Supplemental Material: The online appendices are available at https://doi.org/10.1287/opre.2018.1792. Keywords: gleaning * volunteer * food bank * food waste * food insecurity * dynamic control, 1. Introduction The practice of gleaning combines two societal problems to create an elegant solution for both. Gleaning dates back to ancient times when landowners allowed the poor to gather [...]

This paper studies a multiclass queueing system with endogenous abandonments where congestion affects customers' abandonment behavior, and vice versa. Our model captures this interaction by developing two closely related models: an abandonment model and a queueing model. In the abandonment model, customers take the virtual waiting time distribution as given. Class k customers receive a reward [r.sub.k] from service and incur a cost [c.sub.k] per period of waiting. Customers are forward looking and make wait or abandon decisions dynamically to maximize their expected discounted utilities. The queueing model takes the customers' abandonment time distribution as an input and studies the resulting virtual waiting time distribution. Because the multiclass queueing system is not amenable to exact analysis, we resort to an approximate analysis in the conventional heavy traffic limit (under the hazard rate scaling). Leveraging the so-called state-space collapse property, we provide a characterization of the system performance. Combining the results for the two models, we show that there exists a unique equilibrium in which the customers' abandonment time and the virtual waiting time for the various classes are consistent in the two models. Finally, we provide a computational scheme to calculate the equilibrium numerically and apply that using data from an Israeli bank call center. Supplemental Material: The online appendix is available at https://doi.org/10.1287/opre.2017.1638. Keywords: queueing systems * endogenous abandonments * heavy traffic, 1. Introduction Queueing models with abandonments have been studied extensively in the operations research literature from both the performance analysis and optimization perspectives; see Ward (2011) for a survey. In [...]

Abstract. We undertake an empirical study of the impact of delay announcements on callers' abandonment behavior and the performance of a call center with two priority classes. A Cox regression [...]

We consider a congestible system serving multiple classes of customers who differ in their delay sensitivity and valuation of service (or product). Customers are endowed with convex-concave delay cost functions. [...]

We consider the problem of designing an efficient system for allocating donated livers to patients waiting for transplantation. The trade-off between medical urgency and efficiency is at the heart of [...]

We consider a make-to-order system where customers are dynamically quoted lead times (and prices). Customers are homogenous but have general (nonlinear) disutility for delay. Because the firm is a monopolist, [...]

As a model of make-to-order production, we consider an admission control problem for a multiclass, single-server queue. The production system serves multiple demand streams, each having a rigid due-date lead [...]

A controller dynamically chooses a state-dependent transmission rate on a static, point-to-point wireless link by varying transmission power over time. The transmitter is modeled as a finite-buffer Markovian queue with [...]