Jin-Kyung Kwak

Using an appropriate measure to assess firms’ performance is essential. We analyzed inventory turnover (IT) as a performance measure in manufacturing processes because IT ratios are critical in the manufacturing industry and publicly available objective measures. Using the data of 421 manufacturing companies in Korea from 2010 to 2018, we conducted an extensive analysis of the factors affecting IT by segment and its correlation with other financial ratios. Then, we compare performances between t

This study investigates how information errors affect supply chain performance when a retailer and a supplier share the end-customer demand information. An Enterprise Resource Planning (ERP) system, often used to share information in a supply chain, is not perfect and often contains erroneous information. Companies contemplating the use of ERP systems must evaluate the benefit of using them despite the existence of errors in the system. Our study quantifies the impact of information errors by co

Healthcare institutions generally use an appointment system. However, patients often need to receive medical services unexpectedly. If they visit a clinic without an appointment, they may have to wait for a long time, as their priority is low. In this study, we investigated whether the clinic registration system can be improved by separating the queues and resources for different types of patients. From our simulation results, we found that under a certain setup, the separation policy does not e

In this study, we investigate the effect of having express checkout lanes in retail stores. Express checkout lanes are being used to reduce expected wait time of small-buying customers, but their operational effect has not been analyzed so far. By comparing the wait time and the queue length of the two scenarios (universal checkout lanes only and separated checkout lanes with express counters) via simulation, we have found that the average wait time of the separated checkout lanes may not be sho

In this paper, we analyze the relationship between implementation of information technology and inventory turnover as a measure of operational efficiency. We build a regression model including a dummy variable that indicates whether a firm has been nominated for being good at implementing information technology. By using publicly available data, we have conducted an extensive empirical analysis and found that firms' using information technology is not likely to affect inventory turnover signific

본 연구는 한국 대학생들을 대상으로 간단한 단일기간 재고 의사결정(Newsvendor problem) 실험을 수행하여 얻은 결과를 분석하여 생산운영관리(operations management) 분야 교육의 향상을 추구하고자 하였다. 실험 참가자들은 최근1년 이내 단일기간 재고 모형을 포함한 생산운영관리 과목을 수강한 학생들로 평균 예상수요만 주어진 상태에서 원하는정보를 요청해가며 재고 의사결정을 내리게 되었다. 실험 결과 대부분의 응답자들은 최적 주문량 도출에 결정적인 주요정보를 파악하지 못하였고 특히 수요 분포에 대한 이해가 많이 부족한 것으로 나타났다. 또한 소유한 정보를 바탕으로 주문량을 결정하는 과정에서도 오류를 드러내어 최적 의사결정에 실패하였다. 본 논문에서는 이러한 실험 결과를 분석하여생산운영관리 교육의 질적 향상을 도모하였다. VPA(verbal protocol analysis) 방법론을 활용하여 학생들이 능동적으로 의사결정에 필요한 정보를 적절히 찾아낼 수 있는 능력

As decision makers do not make optimal decisions in practice despite the existence of optimal solutions in many models, there has been a rising interest in behavioral operations management recently. In this study, we aim for a comparative study to analyze the inventory decisions in Korea, America, and China, by conducting the same newsvendor experiment in Korea and compare the results with those of previous studies. From the comparative analysis, some national characteristics in decision-making

Customer satisfaction in retail stores are considerably affected by checkout services. Self-checkout counters have been installed in order to reduce waiting times at checkout in retail stores. However, it is uncertain whether the self-checkout lanes actually decrease the average waiting time of customers. Rather, there are some problems associated with self-checkout lanes such as theft or service failure due to technological problems. This study analyzes comparison between self-checkout and regu

It is important to have an appropriate amount of inventory for effective operations. This study seeks to develop a sustainable newsvendor model by incorporating environment-related costs into the existing well-known (single-period) newsvendor model. Since leftovers do more harm to environments than stockouts, the optimal order amount tends to be lower than the traditional quantity. However, this is not the case when a second buy is allowed. A second order opportunity is prevalent in industries w

In this study, we investigate the supplier’s inventory decision when facing a boundedly rational retailer. Existing literatures mostly assumed perfect rationality of decision makers, but recent studies found out that optimal decisions are not made in most cases. Su (2008) explained the behavioral aspect of newsvendor decisions by bounded rationality. Bounded rationality leads to stochastic decisions – better decisions with higher probabilities – rather than optimal ones. In particular, that stud

This dissertation focuses on how an information-enabled (i.e. there is free flow of demand information from the retailer to the supplier) supply chain utilizes the information about retailer behavior. By understanding, quantifying, and incorporating retailer behavior into the supplier's decision making process, we can significantly improve supplier performance and in some cases, the total supply chain performance as well. The three chapters in this dissertation each deal with a different aspect

This study investigates how discrete choice analysis can be applied to health care operations. Discrete choice analysis helps to understand the complex decision-making process of purchasing expensive medical equipments by identifying relative weights that decision makers impose on each attribute through simple virtual choice experiments. We also verified the usefulness of applying discrete choice analysis to the purchase of medical equipments with empirical evidence.

It has been studied that retailer's using a suboptimal (R, T) policy is often more desirable to make the best use of information flows than the locally optimal (s, S) policy in a two-stage serial supply chain. In this paper, by performing an extensive computational study, we tabulate the benefit of the retailer's using (R, T) policy instead of (s, S) policy in a supply chain with information sharing, and compare it to a maximum possible benefit that could be achieved in a centralized supply chai