In this book, Andrew Harvey sets out to provide a unified and comprehensive theory of structural time series models. Unlike the traditional ARIMA models, structural time series models consist explicitly of unobserved components, such as trends and seasonals, which have a direct interpretation. As a result the model selection methodology associated with structural models is much closer to econometric methodology. The link with econometrics is made even closer by the natural way in which the models can be extended to include explanatory variables and to cope with multivariate time series. From the technical point of view, state space models and the Kalman filter play a key role in the statistical treatment of structural time series models. The book includes a detailed treatment of the Kalman filter. This technique was originally developed in control engineering, but is becoming increasingly important in fields such as economics and operations research. This book is concerned primarily with modelling economic and social time series, and with addressing the special problems which the treatment of such series poses. The properties of the models and the methodological techniques used to select them are illustrated with various applications. These range from the modellling of trends and cycles in US macroeconomic time series to to an evaluation of the effects of seat belt legislation in the UK.

Forecasting, Structural Time Series Models and the Kalman Filter

Praise for the Third Edition: "This is one of the best books available. Its excellent organizational structure allows quick reference to specific models and its clear presentation . . . solidifies the understanding of the concepts being presented."IIE Transactions on Operations EngineeringThoroughly revised and expanded to reflect the latest developments in the field, Fundamentals of Queueing Theory, Fourth Edition continues to present the basic statistical principles that are necessary to analyze the probabilistic nature of queues. Rather than presenting a narrow focus on the subject, this update illustrates the wide-reaching, fundamental concepts in queueing theory and its applications to diverse areas such as computer science, engineering, business, and operations research.This update takes a numerical approach to understanding and making probable estimations relating to queues, with a comprehensive outline of simple and more advanced queueing models. Newly featured topics of the Fourth Edition include:Retrial queuesApproximations for queueing networksNumerical inversion of transformsDetermining the appropriate number of servers to balance quality and cost of serviceEach chapter provides a self-contained presentation of key concepts and formulae, allowing readers to work with each section independently, while a summary table at the end of the book outlines the types of queues that have been discussed and their results. In addition, two new appendices have been added, discussing transforms and generating functions as well as the fundamentals of differential and difference equations. New examples are now included along with problems that incorporate QtsPlus software, which is freely available via the book's related Web site.With its accessible style and wealth of real-world examples, Fundamentals of Queueing Theory, Fourth Edition is an ideal book for courses on queueing theory at the upper-undergraduate and graduate levels. It is also a valuable resource for researchers and practitioners who analyze congestion in the fields of telecommunications, transportation, aviation, and management science.

Fundamentals of Queueing Theory

https://ira.lib.polyu.edu.hk/bitstream/10397/1269/1/SetupSurvey-2006%28June-19%29.pdf

A survey of scheduling problems with setup times or costs

https://epublications.marquette.edu/cgi/viewcontent.cgi?article=1270&context=mgmt_fac

Qualitative case studies in operations management: Trends, research outcomes, and future research implications

Call centers are an increasingly important part of today's business world, employing millions of agents across the globe and serving as a primary customer-facing channel for firms in many different industries. Call centers have been a fertile area for operations management researchers in several domains, including forecasting, capacity planning, queueing, and personnel scheduling. In addition, as telecommunications and information technology have advanced over the past several years, the operational challenges faced by call center managers have become more complicated. Issues associated with human resources management, sales, and marketing have also become increasingly relevant to call center operations and associated academic research.

In this paper, we provide a survey of the recent literature on call center operations management. Along with traditional research areas, we pay special attention to new management challenges that have been caused by emerging technologies, to behavioral issues associated with both call center agents and customers, and to the interface between call center operations and sales and marketing. We identify a handful of broad themes for future investigation while also pointing out several very specific research opportunities.

/pdf/the-modern-call-center-a-multi-disciplinary-perspective-on-2kcrgkbqth.pdf

The Modern Call Center: A Multi-Disciplinary Perspective on Operations Management Research

This paper outlines approaches for assessing and classifying manufacturing and service operations in terms of their suitability for use of cross-trained (flexible) workers. We refer to our overall framework as agile workforce evaluation. The primary contributions of this paper are: (i) a strategic assessment framework that structures the key mechanisms by which cross-training can support organizational strategy; (ii) a tactical framework that identifies key factors to guide the selection of an architecture and worker coordination policy for implementing workforce agility; (iii) a classification of workforce agility architectures; (iv) a survey of a broad range of archetypical classes of worker coordination policies; (v) a survey of the literature with an operational perspective on workforce agility; and (vi) identification of opportunities for research and development of architectures for specific production environments.

/pdf/agile-workforce-evaluation-a-framework-for-cross-training-1ay4oehvee.pdf

Agile workforce evaluation: a framework for cross-training and coordination

To gain insight into the potential logistical benefits of worker cross-training and agile workforce policies, we study simple models of serial production systems with flexible servers operating under a constant work-in-process (CONWIP) release policy. Two important and interrelated issues are: (a) how to decide which skill(s) are strategically most desirable for workers to gain, and (b) how to coordinate these workers to respond dynamically to congestion. We address these by considering two cross-training strategies: a straightforward capacity-balancing approach, which we call cherry picking (CP), and an innovative overlapping zone strategy that we call skill chaining . Our comparison shows that skill-chaining strategies have the potential to be robust and efficient methods for implementing workforce agility in serial production lines.

Benefits of Skill Chaining in Serial Production Lines with Cross-Trained Workers

In this paper, we present a new perspective on flexibility in manufacturing and service operations by exploring a type of operational flexibility that we term "structural flexibility (SF)." We focus on strategic-level issues of how flexibility can be created by using multipurpose resources such as cross-trained labor, flexible machines, or flexible factories. The proposed structural flexibility method uses the structure of the capability pattern to generate indices that quantify the ability of a system to respond to variability in its environment. Simulations of serial and parallel queueing networks provide evidence that this index is useful in predicting the performance rank of alternative designs for implementing multifunctionality in the face of variability. The proposed methodology supports managerial insight into structural design of manufacturing and service systems at the strategic level.

http://users.iems.northwestern.edu/~iravani/Structural_Flexibility.pdf

Structural Flexibility: A New Perspective on the Design of Manufacturing and Service Operations

To gain insight into the potential logistical benefits of worker cross-training and agile workforce policies, we study simple models of flexible workers in serial production systems. The primary control issue is how to assign workers to jobs/stations over time. Under assumptions of complete worker flexibility and collaborative work, we prove that a simple expedite policy minimizes along each sample path the cycle time (delay) for each job. Therefore, the expedite policy also minimizes work in process and maximizes throughput along every sample path. We also compute the performance improvement opportunity achievable using flexible workers as opposed to the optimal static allocation of workers. This enables us to examine the factors that make workforce agility a potentially attractive strategy. We also consider the intuitive analog of the expedite policy for the noncollaborative work environment, which we call the pick-and-run policy; however, we demonstrate by counterexample that it is not always optimal. Finally, we extend some of our insights from the demand-constrained environment to a capacity-constrained environment operating under a CONstant WIP (CONWIP) protocol.

Performance opportunity for workforce agility in collaborative and noncollaborative work systems

Crisis-level overcrowding conditions in emergency departments EDs have led hospitals to seek out new patient-flow designs to improve both responsiveness and safety. One approach that has attracted attention and experimentation in the emergency medicine community is a system in which ED beds and care teams are segregated and patients are “streamed” based on predictions of whether they will be discharged or admitted to the hospital. In this paper, we use a combination of analytic and simulation models to determine whether such a streaming policy can improve ED performance, where it is most likely to be effective, and how it should be implemented for maximum performance. Our results suggest that the concept of streaming can indeed improve patient flow, but only in some situations. First, ED resources must be shared across streams rather than physically separated. This leads us to propose a new “virtual-streaming” patient flow design for EDs. Second, this type of streaming is most effective in EDs with 1 a high percentage of admitted patients, 2 longer care times for admitted patients than discharged patients, 3 a high day-to-day variation in the percentage of admitted patients, 4 long patient boarding times e.g., caused by hospital “bed-block”, and 5 high average physician utilization. Finally, to take full advantage of streaming, physicians assigned to admit patients should prioritize upstream new patients, whereas physicians assigned to discharge patients should prioritize downstream old patients.

/pdf/patient-streaming-as-a-mechanism-for-improving-54a77c8rp3.pdf

Mark P. Van Oyen

Papers

Agile workforce evaluation: a framework for cross-training and coordination

Benefits of Skill Chaining in Serial Production Lines with Cross-Trained Workers

Structural Flexibility: A New Perspective on the Design of Manufacturing and Service Operations

Performance opportunity for workforce agility in collaborative and noncollaborative work systems

Patient Streaming as a Mechanism for Improving Responsiveness in Emergency Departments