Ram Ganeshan

Quantitative Models for Supply Chain Management

From the Publisher: Quantitative models and computer based tools are essential for making decisions in todays business environment. These tools are of particular importance in the rapidly growing area of supply chain management. This volume is a unified effort to provide a systematic summary of the large variety of new issues being considered, the new set of models being developed, the new techniques for analysis, and the computational methods that have become available recently. The volumes objective is to provide a self-contained, sophisticated research summary - a snapshot at this point of time - in the area of Quantitative Models for Supply Chain Management. This volume can serve as a graduate text, as a reference for researchers and as a guide for further development of this field.

MANAGING SUPPLY CHAIN INVENTORIES: A MULTIPLE RETAILER, ONE WAREHOUSE, MULTIPLE SUPPLIER MODEL

Abstract Inventories exist throughout the supply chain in various forms for various reasons. Since carrying these inventories can cost anywhere from 20 to 40% of their value a year, managing them in a scientific manner to maintain minimal levels makes economic sense. This paper presents a near-optimal (s, Q) -type inventory policy for a production/distribution network with multiple suppliers replenishing a central warehouse, which in turn distributes to a large number of retailers. The model is a synthesis of three components: (i) the inventory analysis at the retailers, (ii) the demand process at the warehouse, and (iii) the inventory analysis at the warehouse. The key contribution of the model is the seamless integration of the three components to analyze simple supply chains. The decisions in the model were made through a comprehensive distribution-based cost framework that includes the inventory, transportation, and transit components of the supply chain.

A Taxonomic Review of Supply Chain Management Research

In the previous chapters, we focused largely on quantitative approaches to solving Supply Chain Management (SCM) problems including such issues as: inventory management, supply contracts, information flow, product variety, and international operations. In this chapter, we will broaden our focus to include other approaches to SCM problems, by presenting a broad taxonomy for understanding SCM research.

The impact of inventory and flow planning parameters on supply chain performance: An exploratory study

Abstract The primary objective of this paper is to study the impact of selected inventory parameters and management techniques on the performance of an expanded and comprehensive retail supply chain. Specifically, we study the sensitivity of supply chain performance to three inventory planning parameters: (i) the forecast error, (ii) the mode of communication between echelons, and (iii) the planning frequency. We achieve this by constructing a detailed simulation model and with data adapted from a case study which we were involved with. The studies conclude that all the three parameters have a significant effect on performance. Increasing forecasting errors and the re-planning frequency decreases service, return on investment, and increases cycle time. Using a mode of communication that facilitates exchange of information between echelons in the supply chain yields a higher level of service when compared to the scenario where the entities in different echelons plan material flows independently.

Learning and Knowledge Depreciation in Professional Services

Organizational knowledge is a critical source of competitive advantage for professional service firms. Learning from experience and sustaining past knowledge are critical to the success of such knowledge-driven firms. We use learning curve theory to evaluate learning and depreciation in professional services. Our results, based on seven years of project data collected from an architectural engineering (A/E) firm, show that (a) professional services exhibit learning curves, (b) there is virtually no depreciation of knowledge and, (c) the rate of learning accelerates with experience.

Production economics and process quality: A Taguchi perspective

Abstract Although several studies have analyzed the interaction between the economics of production and process quality, most of them view quality from a very traditional perspective – reject when outside specified limits, or else accept. Recent views on quality have shown that such a definition greatly underestimates the costs of poor quality and leads to sub-optimal decisions. The primary intent in this paper is to revisit this interaction of the economics of production with process quality from a non-traditional yet more realistic “Taguchi” quality cost perspective. Specifically, we investigate the possibility of investing in a process to decrease its variance. Although such an investment reduces the proportion of defects, and when large enough, the Taguchis loss, it also increases the cost of holding inventory. Our model determines the optimal levels of inventory, and the production lot-size that minimizes the sum of inventory and quality-related costs.

The effect of information technology on learning in professional service organizations

Abstract This study examines the relationship between organizational experience and productivity in a professional service organization. The research addresses a gap in the existing literature with respect to organizational experience models in service organizations. Our findings confirm a significant, positive relationship between organizational experience and productivity. In addition, we investigate the effect of information technology on the relationship between organizational experience and productivity. The findings indicate that information technology which becomes a part of the production process is associated with productivity improvements, while information technology which merely documents or collects information is not.

DUAL SOURCED SUPPLY CHAINS: THE DISCOUNT SUPPLIER OPTION

In this paper, we examine the dynamics of a supply chain that has the option of using two suppliers - one reliable, and the other unreliable. We characterize the unreliable supplier with long lead-time mean and variance. Although the use of the unreliable supplier might potentially warrant higher inventory and transportation costs, it is attractive because of the willingness of the supplier to provide a discount on the purchase price. We analyze the cost economics of two suppliers in a broader inventory-logistics framework, one that includes in-transit inventories and transportation costs. In this broader perspective, we provide a simple heuristic and sample exchange curves to determine: (i) if the order should be split between the suppliers; and (ii) if the order is split, the amount of discount and the fraction ordered to the secondary supplier to make order-splitting a worth-while policy. ©

The Impact of Imperfect Processes on Production Run Times

This paper investigates the interaction between the economics of production and imperfections in the production process. Specifically, this paper is the first to devise a model in an attempt to provide managers with guidelines to choose the appropriate production run times to buffer against both the production of defective items and stoppages occurring due to machine breakdowns. In addition to providing several structural properties of the model, we show that a manager will always incur a cost penalty when (s)he uses the results of two oft-cited models-the EMQ (Economic Order/Manufacturing Quantity) and the NR-E (No-Resumption, Exponential machine breakdown)-to determine production run times.

By the Numbers: A Visual Chronicle of Carbon Dioxide Emissions

Carbon dioxide equivalent (CO2-eq.) emissions are now considered a de facto indicator of environmental impact. Through a series of visuals, this chapter highlights the size and scope of carbon emissions at multiple levels—countries, cities, industrial sectors and products.