Quasi Random Sampling for Operations Management

We look at the benefits of using a kind of quasi-random numbers to obtain more accurate results for a given number of simulation runs. We explore a sampling method with enhanced independence in multidimensional simulations by combining the ideas of stratified sampling and Latin Hypercube sampling. We test the new sampling method by comparing it with traditional stratified sampling and Latin Hypercube sampling applied to various operations management problems

Object-Oriented Simulation Model for Tandem Tollbooth Operations using Pro-Model

This paper presents a new object-oriented simulation model to describe tandem tollbooth system in order to evaluate the operational performance of toll plaza facilities. This microscopic traffic simulation model is used to enhance planning, design, operations, and management of traffic operation at toll plazas. Computational result shows that lower reaction time ratio increases the throughput capacity of tandem tollbooth.This paper would not have been possible unless there is no support from IOE department at the University of Michigan. This research was supported by the Institute of Management Research Institute at Seoul National University

Leader's Role in Fostering Creativity: The Creativity Creation Model at KT AIT

To achieve innovation, constraints that block the effect of a company's creative culture on innovation and creativity in the organization have to be removed. We propose the creativity creation model that takes account of these constraints and suggest that, to cultivate an innovative climateleaders should receive feedback from innovation performance. To improve creativity and achieve successful innovation, leaders should be involved in every procedure of the model. We explore the three main procedures of the model and present a practical application to the case of a Korean telecommunications company's research and development institute, KT AIT. [ABSTRACT FROM AUTHOR] Copyright of Seoul Journal of Business is the property of Seoul National University, College of Business Administration and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)This research was supported by the Institute of Management Research at Seoul National University

Structural, magnetic and transport properties in the Cu-doped manganites La0.85Te0.15Mn1-xCuxO3 (0 \leq x \leq 0.20)

The effect of Cu-doping at Mn-site on structural, magnetic and transport properties in electron-doped manganites La0.85Te0.15Mn1-xCuxO3 has been investigated. Based on the analysis of structural parameter variations, the valence state of the Cu ion in Cu-doped manganites is suggested to be +2. All samples undergo the paramagnetic-ferromagnetic (PM-FM) phase transition. The Curie temperature decreases and the transition becomes broader with increasing Cu-doping level, in contrast, the magnetization magnitude of Cu-doping samples at low temperatures increase as x \leq 0.15. The insulator-metal (I-M) transition moves to lower temperatures with increasing Cu-doping content and disappears as x > 0.1. In addition, the higher temperature resistivity r peak in double-peak-like r(T) curves observed in no Cu-doping sample is completely suppressed as Cu-doping level x = 0.1 and r(T) curve only shows single I-M transition at the low temperature well below . The results are discussed according to the change of magnetic exchange interaction caused by Cu-doping.Comment: 17 pages, 5 figures. Phys.Rev.B (to be published

Conditions that cause risk pooling to increase inventory

We say product A is a partial substitute for product B if a fraction of the customers who prefer B are willing to accept A when B is out of stock. When demand is uncertain, it is intuitive and true that a larger "willing to substitute" fraction implies larger expected profits. A higher "willing to substitute" fraction allows one to pool the risk of individual products. It may also be intuitive that a larger "willing to substitute" fraction might result in lower optimal total inventory. For the full substitution structure, several researchers have shown that for certain distributions such as the exponential, this latter intuition is not true. We show that this full substitution anomaly can occur with any right skewed demand distribution. We assume i.i.d. demand distributions unless we indicate otherwise. We also show that the anomaly can occur for a number of realistic situations of partial substitution with commonly used demand distributions such as Normal, exponential, Poisson, and uniform. We also demonstrate the anomaly for more than one period, with backlogging, lost sales, more than two products, and with setup costs.Inventory Demand substitution Risk pooling

Does Reduction of Material and Energy Consumption Affect to Innovation Efficiency? The Case of Manufacturing Industry in South Korea

“Reduction of material and energy consumption„ (RMEC) exists as a major objective of innovation and it is proved to affect positively to innovation performance from previous literature. Though innovation should be measured in efficiency rather than performance itself, however, the relationship between material and energy reduction on innovation efficiency is still unanswered. In this paper, we analyzed the effect of RMEC on innovation efficiency considering both innovation inputs and outputs. We utilized data of 388 manufacturing enterprises in Korea, and performed data envelopment analysis (DEA) and tobit regression analysis. According to the result, firms show difference by industry type in terms of innovation efficiency and RMEC. Moreover, the effect of RMEC on innovation efficiency turned out to be negative. The result indicates a possibility that input used for innovation might overweigh the output yielded when firms pursue innovation for the RMEC