Jayant Rajgopal

A Classification Scheme for the Process Industry to Guide the Implementation of Lean

Abstract: Lean manufacturing has traditionally been thought of as being applicable mostly to the discrete manufacturing industries since the process sector lends itself less naturally to many lean techniques. There is, however, considerable interest in extending lean to the process industries because of its dramatic results in the discrete sector. We argue that different lean techniques can be applied in varying degrees depending on the specific characteristics of the process environment. In this article we develop a general classification scheme for the process industry, which managers of companies in this sector can use in order to identify and guide the implementation of specific lean techniques that could be applicable to them.

Optimization of indoor wireless communication network layouts

Radio Frequency Data Communications (RFDC)technology is rapidly becoming a critical component of many traditional industrial engineering functions including materials tracking, inventory control, warehousing, order processing, shipping and database management. As a means of moving information, RFDC has many attractive features, such as speed, accuracy, reliability, convenience and low operating costs. When implementing RFDC systems a major problem is to quickly and efficiently determine the locations where transceivers should be placed so that effective radio communication can take place. The research described in this paper addresses this issue by developing a computerized layout simulation system that incorporates heuristic optimization methods to solve the placement problem. The effectiveness of this unique automated layout methodology is demonstrated by comparing it with the current method of utilizing manual site surveys, as well as with other placement methods. The methodology and solutions are validated by field-testing at actual facilities.

An extension of Palmer's heuristic for the flow shop scheduling problem

We describe a simple modification of Palmers heuristic for scheduling jobs in a flow shop. While the additional computation required is relatively small, the performance of the algorithm compares very well with that of the more sophisticated and better algorithm of Campbell, et al. (1970) at a fraction of the effort required by the latter.

Single versus multi-dose vaccine vials: an economic computational model.

Single-dose vaccine formats can prevent clinic-level vaccine wastage but may incur higher production, medical waste disposal, and storage costs than multi-dose formats. To help guide vaccine developers, manufacturers, distributors, and purchasers, we developed a computational model to predict the potential economic impact of various single-dose versus multi-dose measles (MEA), hemophilus influenzae type B (Hib), Bacille Calmette-Guérin (BCG), yellow fever (YF), and pentavalent (DTP-HepB-Hib) vaccine formats. Lower patient demand favors fewer dose formats. The mean daily patient arrival thresholds for each vaccine format are as follows: for the MEA vaccine, 2 patients/day (below which the single-dose vial and above which the 10-dose vial are least costly); BCG vaccine, 6 patients/day (below, 10-dose vial; above, 20-dose vial); Hib vaccine, 5 patients/day (below, single-dose vial; above, 10-dose vial); YF vaccine, 33 patients/day (below, 5-dose vials; above 50-dose vial); and DTP-HepB-Hib vaccine, 5 patients/day (below, single-dose vial; above, 10-dose vial).

Impact of changing the measles vaccine vial size on Niger's vaccine supply chain: a computational model

BackgroundMany countries, such as Niger, are considering changing their vaccine vial size presentation and may want to evaluate the subsequent impact on their supply chains, the series of steps required to get vaccines from their manufacturers to patients. The measles vaccine is particularly important in Niger, a country prone to measles outbreaks.MethodsWe developed a detailed discrete event simulation model of the vaccine supply chain representing every vaccine, storage location, refrigerator, freezer, and transport device (e.g., cold trucks, 4 × 4 trucks, and vaccine carriers) in the Niger Expanded Programme on Immunization (EPI). Experiments simulated the impact of replacing the 10-dose measles vial size with 5-dose, 2-dose and 1-dose vial sizes.ResultsSwitching from the 10-dose to the 5-dose, 2-dose and 1-dose vial sizes decreased the average availability of EPI vaccines for arriving patients from 83% to 82%, 81% and 78%, respectively for a 100% target population size. The switches also changed transport vehicles utilization from a mean of 58% (range: 4-164%) to means of 59% (range: 4-164%), 62% (range: 4-175%), and 67% (range: 5-192%), respectively, between the regional and district stores, and from a mean of 160% (range: 83-300%) to means of 161% (range: 82-322%), 175% (range: 78-344%), and 198% (range: 88-402%), respectively, between the district to integrated health centres (IHC). The switch also changed district level storage utilization from a mean of 65% to means of 64%, 66% and 68% (range for all scenarios: 3-100%). Finally, accounting for vaccine administration, wastage, and disposal, replacing the 10-dose vial with the 5 or 1-dose vials would increase the cost per immunized patient from

Solving Posynomial Geometric Programming Problems via Generalized Linear Programming

0.47US to

The benefits of redesigning Benin's vaccine supply chain

0.71US and

Impact of introducing the pneumococcal and rotavirus vaccines into the routine immunization program in Niger

1.26US, respectively.ConclusionsThe switch from the 10-dose measles vaccines to smaller vial sizes could overwhelm the capacities of many storage facilities and transport vehicles as well as increase the cost per vaccinated child.

Optimal Reliability Allocation with Discrete Cost-Reliability Data for Components

This paper revisits an efficient procedure for solving posynomial geometric programming (GP) problems, which was initially developed by Avriel et al. The procedure, which used the concept of condensation, was embedded within an algorithm for the more general (signomial) GP problem. It is shown here that a computationally equivalent dual-based algorithm may be independently derived based on some more recent work where the GP primal-dual pair was reformulated as a set of inexact linear programs. The constraint structure of the reformulation provides insight into why the algorithm is successful in avoiding all of the computational problems traditionally associated with dual-based algorithms. Test results indicate that the algorithm can be used to successfully solve large-scale geometric programming problems on a desktop computer.

Removing the regional level from the Niger vaccine supply chain

INTRODUCTION New vaccine introductions have put strains on vaccine supply chains around the world. While increasing storage and transportation may be the most straightforward options, it is also important to consider what financial and operational benefits can be incurred. In 2012, suboptimal vaccine coverage and impending vaccine introductions prompted the Republic of Benins Ministry of Health (MOH) to explore ways to improve their vaccine supply chain. METHODS Working alongside the Beninese MOH, we utilized our computational model, HERMES, to explore the impact on cost and vaccine availability of three possible options: (1) consolidating the Commune level to a Health Zone level, (2) removing the Commune level completely, and (3) removing the Commune level and expanding to 12 Department Stores. We also analyzed the impact of adding shipping loops during delivery. RESULTS At baseline, new vaccine introductions without any changes to the current system increased the logistics cost per dose (