Gamini Gunawardane

Dynamic versions of set covering type public facility location problems

Abstract This paper considers several multi-period public facility planning decision problems such as multi-period service coverage, multi-period service phase-out, and multi-period maximum coverage. Models for these situations and computational experience are presented.

Reliability of the internal service encounter

Purpose – Service quality has been an active area of research during the last two decades. In this research, typically, service quality is considered from the viewpoint of the customer who is the recipient of the service, i.e. the “external customer”, and the research efforts have focused on identifying the dimensions of quality in this “external service encounter”. In the majority of these studies, “reliability” has been identified as the most prominent dimension among the various dimensions of the external service encounter. In recent times, researchers have also highlighted the importance of “internal customers” and the existence of an “internal service encounter”. The objectives of the research project reported here were: to investigate whether “reliability” is perceived as an important dimension in the internal service encounter as well, and, if so, to ascertain how service managers define “reliability” in the internal service encounter; and to examine whether the perceived importance of “reliability...

Addition of Ipratropium to Nebulized Albuterol in Children with Acute Asthma Presenting to a Pediatric Office

A prospective, randomized, double-blind study was conducted to determine whether there was any benefit to the addition of ipratropium to a single nebulized albuterol treatment in infants and children with mild to moderate acute asthma presenting to a pediatric office. There were no significant differences between the albuterol group and the combined albuterolipratropium group in the relief of the respiratory distress, disposition of the patients from the office, or in the incidence of relapse. The addition of ipratropium to nebulized albuterol is of no added benefit in the treatment of infants and children with mild-to-moderate acute asthma presenting to a pediatric office.

Variations of Trypia's model for production planning

In a recent issue of this journal, Trypia presented a mixed‐integer programming model to plan production of a line of products in several departments of a firm. Strict capacity restrictions were imposed on each production facility. This paper presents three variations of Trypias model suitable for discussion in production management and mathematical modelling courses. First, it presents the uncapacitated version of Trypias problem, mainly to highlight an interesting and useful structural property in the model. Next, a more realistic version of Trypias problem, in which alternative short‐term capacity expansion strategies, such as overtime, extra shifts and sub‐contracting are available to management, is presented. Finally, the multi‐period version of Trypias problem is discussed.

Variations and extensions of Proll's integer linear programming formulation techniques for the graph partitioning problem

In a recent issue of this journal, Proll presented a graph partitioning problem to illustrate how tighter formulations of integer linear programs (ILP) result in reduced computational effort. This paper presents a large number of other problems where tighter formulations of the associated ILPs lead to similar benefits thus providing a more comprehensive framework for discussing ILP formulations in industrial engineering and mathematical modelling courses.

Mathematical modelling education in U.S. business schools

This paper reviews the role played by the required undergraduate course in Management Science/Quantitative Methods, in U.S. business and management schools, in teaching modelling concepts and techniques to business students; it also reports the findings of a survey of this course in the business schools accredited by the American Assembly of Collegiate Schools of Business (AACSB). The findings clearly show a trend towards incorporating more applications, examples, cases from functional areas (marketing, production, finance and personnel) and microcomputer usage, and an effort to design the course in line with the reported corporate use of modelling techniques.

Generalized versions and extensions of Trypia's blending problem

In a recent issue of this journal, Trypia presented a simple rule to determine the blending pattern and quantities for a multi‐product blending firm. This paper presents three variations of Trypias model suitable for discussion in production management and mathematical modelling courses. First, it presents a generalized version of Trypias problem leading to a linear programming formulation. Next a more realistic version of Trypias problem including set‐up costs is presented together with a simple method for determining production sequence and quantities. Finally, the case of sequence dependent set‐up costs is discussed.