Commissioned Papers

M&SOM is pleased to announce a series of commissioned papers, written by pre-eminent scholars in their fields of study.


Title: "To Pull or not to Pull: What is the Question?"

Author(s): Mark L. Spearman and Wallace J. Hopp

Abstract: The Toyota Production System (TPS) represents the embodiment of "Lean"production. One of the foundations of the TPS is "pull production,"typified by a system known as "kanban." Researchers have studied kanban systems for years and, until recently, there was relatively little debate as to what is and what is not a pull production system. The recent "Lean" practitioner literature has led to many more implementations of pull beyond kanban and has caused a great deal of confusion of what actually drives improvement under TPS and, indeed, what is meant by pull. 

In this paper, we trace the sources of the literary threads in both the practitioner and research literatures and posit reasons for the current confusion. We offer a precise definition of pull and discuss implementation options.

This leads us to an explanation of why TPS really works and how it can be extended to more general environments.


Title: "Airline Schedule Planning Accomplishments and Opportunities"

Author(s): Cynthia Barnhart and Amy Mainville Cohn

Abstract: Optimization has played an important role in aircraft and crew schedule planning for many decades. In this survey paper, we review modeling and algorithmic approaches for the design of tight schedules, and the assignment and routing of aircraft and tight crews. We describe how approaches have evolved to take advantage of advances in optimization theory and computational speed and power. Exective modeling and algorithmic techniques, including problem structure exploitation, are detailed.  The impact of these approaches on selected airlines, both in terms of the planning processes and airline profitability, are discussed. We conclude with a description of ongoing challenges in the airline industry and future research opportunities.  

Accepted and Published in 4:1

Title: "Forecast, Solution and Rolling Horizons in Operations Management: A Classified Bibliography"

Author(s): Suresh Chand, Suresh Sethi, Vernon Hsu

Abstract: We present a classified bibliography of the literature in the area of forecast, solution, and rolling horizons primarily in operations management problems. Each of over 200 selected papers is categorized on five dimensions that identify the horizon type, the model type (deterministic or stochastic), the sources of horizon, the methods used to obtain horizon results, and the subject area of the paper. The majority of the papers treat dynamic problems in inventory management, production planning, capacity expansion, machine replacement, and warehousing.

Accepted and Published in 5:2

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.

Accepted and Published in 5:3

Title: "On the Interface between Operations and Human Resources Management"

Author(s): John Boudreau, Wallace Hopp, John McClain, and L. Joseph Thomas

Abstract: Operations management (OM) and human resources management (HRM) have historically been very separate fields.  In practice, operations managers and human resource managers interact primarily on administrative issues regarding payroll and other matters.  In academia, the two subjects are studied by separate communities of scholars publishing in disjoint sets of journals, drawing on mostly separate disciplinary foundations.  Yet, operations and human resources are intimately tied to one another in virtually all business environments.  Operations are the context that often explains the effects of human resource activities such as pay, training, communications and staffing.  Human responses to operations management systems often explain variations or anomalies that would otherwise be treated as randomness or error variance in traditional operations research models.  HRM can gain perspective and better identify key priorities by better understanding OM.  OM can better design and predict the effects of its systems by understanding how humans respond.  To date, relatively little research has been directed at understanding and exploiting this synergy.  In this paper, we probe the interface between operations and human resources by examining how human considerations affect classical OM results and how operational considerations affect classical HRM results. For example, when are “optimal” solutions not even good? When and why does human behavior cause significantly more or less productivity than predicted?  With these in mind, we propose a unifying framework for identifying new research opportunities at the intersection of the two fields.

Accepted and Published in 5:3

Title: "An Overview of Pricing Models and Revenue Management"

Author(s): Gabriel Bitran, Rene Caldentey, 

Abstract: In this paper we examine the research and results of dynamic pricing policies and their relation to Revenue Management. The survey is based on a generic Revenue Management problem in which a perishable and non-renewable set of resources satisfy stochastic price-sensitive demand processes over a finite period of time. In this class of problems, the owner (or the seller) of these resources uses them to produce and offer a menu of final products to the end customers. Within this context, we formulate the stochastic control problem of capacity that the seller faces: how to dynamically set the menu and the quantity of products and their corresponding prices in order to maximize the total revenue over the selling horizon.

Accepted and Published in 5:4

Title: "Capacity Management, Investment, and Hedging: Review and Recent Developments"

Author(s): Jan A. Van Mieghem

Abstract: This article surveys the literature on stochastic capacity investment and presents new work on hedging the risk of the investment porfolio by purposely unbalancing capacities. Capacity in this article relates to upper bounds on the production quantities of a firm resulting from limitations in its processing network. While many factors can limit production quantities, including inventory shortage, scheduling, flow time, and reliability, the discussion here will focus on the prime economic factors of production: capital and labor resources. Investment is the change of the stock of capital and labor and includes expansion and contraction. A general stochastic capacity investment model and its major properties are presented together with a discussion of important issues in the formulation of capacity problems. Recent directions in stochastic capacity investment are discussed: investment in multiple resources, investment by multiple agents, and investment that incorporates risk considerations. We focus on optimal investment and operational hedging in a portfolio of capacity types or "real assets" as opposed to financial assets. We present new results on the efficient risk-return frontier and the optimal risk-hedging capacity adjustment path. This suggests a measure for the value of operational hedging by purposely deviating from a balanced capacity  configuration (or from the risk-neutral optimal configuration as prescribed by a newsvendor network solution). An ongoing example illustrates the discussion.

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