Volume 5:2

Copies of these published papers may be downloaded from Informs Online

Title: "Managing Variety for Assembled Products: Modeling Component Systems Sharing"

Author(s): Kamalini Ramdas

Abstract:  Component sharing – using the same version of a component across multiple products – is an approach adopted by many assembled product manufacturers to achieve high final product variety with lower component variety and cost. This paper presents a methodology for determining which versions of a set of related components should be offered to optimally support a defined finished product portfolio. We develop optimization models that determine which versions of each component should be introduced and which of these versions each product should use so as to minimize design and production costs. This approach is appropriate for components with a relatively low impact on consumers’ perceptions about product differentiation, which can be shared across a set of products if they meet the most stringent performance requirements in the set. We illustrate our procedure on automotive braking systems, but also discuss its applicability to other components and industries. Finally, we consider organizational issues and identify three conceptually different approaches to component sharing: a coordinated projects approach that requires higher-level organizational echelons above the individual project, a project-by-project approach that does not, and a hybrid partially sequential approach.  We use our model to show that the gain from the coordinated projects approach relative to the project-by-project approach increases when there are more feasible design alternatives, but is not impacted by product demand variability.  We also use our model to highlight the risk of using simplistic heuristics to determine design sequence within a component system in a partially sequential approach.

The Consulting Senior Editor was Tim Lowe.

The manuscript was submitted on January 31, 2003.  The average review cycle time was 58 days.

Corresponding author: Kamalini Ramdas, University of Virginia, Darden Graduate School of Business, Charlotte, NC 22906, Phone: 434-243-7685, Email: ramdask@darden.virginia.edu.

Title: "Telephone Call Centers: Tutorial, Review and Research Prospects"

Author(s): Noah Gans, Ger Koole, Avishai Mandelbaum

Abstract: Telephone call centers are an integral part of a wide variety of businesses, and their place in many economies is large and growing. They are also fascinating socio-technical systems in which the behavior of customers and employees is closely intertwined with physical measures of performance. While traditional operational models are useful in this context, they must also be extended and broadened to better characterize the call-center environment.

In this article, we describe the state of research on telephone call centers. We begin with a tutorial on how call centers function and proceed to survey the academic literature on the management of call-center operations. We then outline important problems that have not been addressed, and conclude with identifying promising directions for future research.

Title: "Optimal Replenishment Policies for Multiechelon Inventory Problems Under Advance Demand Information"

Author(s): Guillermo Gallego, Özalp Özer

Abstract: Customers and downstream supply chain partners often place, or can be induced to place, orders in advance of future requirements.  We show how to optimally incorporate advance demand information into periodic-review, multiechelon, inventory systems in series.  While the state space for series systems appears to be formidably large, we decompose the problem across locations, as in Clark and Scarf (1960), and reduce the state space at each location by using modified echelon inventory positions (that nets known requirements).  We horizon problems.  We also show that myopic policies are optimal and very easy to compute when costs and demands are stationary.  We provide managerial insights into the value of advance demand information through a numerical study.

Title: "Erratum: Optimizing Strategic Safety Stock Placement in Supply Chains"

Author(s): Stephen C. Graves, Sean P. Willems

Copyright ©1996, Manufacturing & Service Operations Management,
Krannert Graduate School of Management, Purdue University