• 산업경영시스템학회지
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• 제28권2호
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• pp.117-124
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• 2005

This study tries to develop the models of measuring the level of product availability accommodated for features of specific customers dividing customers into VIP customers and general customers. Functions of costs that the models are composed of are cost of holding safety stock and cost of lost opportunities. The existing model of measuring the level of product availability which focused on cost of holding safety stock for VIP customers should be reinforced by considering cost of lost opportunities caused by general customers' quitting trades with a company. This study tries to present realistic solutions for problems in making decisions related to the total inventory. This study concludes that the model of the level of product availability meeting general customers' needs is more efficient according to increasing of a latent demand of the general customers who quit trades with a company and the cost of lost opportunities.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.311-314
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• 2005

Supply chain optimization is one of the most important components in the optimization of a company's value chain. This paper considers the problem of designing the supply chain for a product that is represented as an assembly bill of material (BOM). In this problem we are required to identify the locations at which different components of the product arc are produced/assembled. The objective is to minimize the overall cost, which comprises production, inventory holding and transportation costs. We assume that production locations are known and that the inventory policy is a base stock policy. We first formulate the problem as a 0-1 nonlinear integer programming model and show that it can be reformulated as a 0-1 linear integer programming model with an exponential number of decision variables.

• Industrial Engineering and Management Systems
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• 제13권4호
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• pp.398-407
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• 2014

Shortages and delays in a humanitarian logistics system can contribute to the pain and suffering of survivors or other affected people. Humanitarian logistics budgets should be sufficient to prevent such shortages or delays. Unlike commercial supply chain systems, the budgets for relief supply chain systems should be able to satisfy demand. This study describes a comprehensive model in an effort to satisfy the total relief demand by minimizing logistics operations costs. We herein propose a strategic model which determines the locations of distribution centers and the total inventory to be stocked for each distribution center where a flood or other catastrophe may occur. The proposed model is formulated and solved as a mixed-integer programming problem that integrates facility location and inventory decisions by considering capacity constraints and time restrictions in order to minimize the total cost of relief operations. The proposed model is then applied to a real flood case involving 47 disaster areas and 13 distribution centers in Thailand. Finally, we discuss the sensitivity analysis of the model and the managerial implications of this research.

• International Journal of Quality Innovation
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• 제9권1호
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• pp.68-93
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• 2008

The steel bars account for a high percentage of material costs for the current construction projects. At the present time, most of the construction projects for the factories of thin-film transistor liquid crystal display (TFT-LCD) complete the transactions of steel bars when the suppliers ship the steel bars to the temporary storage/processing sites. This paper applies the buy-in concept in the Theory of Constraint (TOC) on the supply chain of steel bars. In this study, suppliers are required to establish warehouses at the construction sites and complete the transactions when the formed and processed steel bars are shipped into the factory sites. The aim is to find a win-win solution to meet with the expectations from constructors as they hope that there is no need to build up inventories but supply is ready at any time. Also, this paper compares and analyzes the traditional supply/inventory model of steel bars and the Demand-Pull (D-P) model under the TOC framework. It is proved that Vendor Management Inventory (VMI) in the D-P model is able to more effectively manage steel bars as a material.

• 대한산업공학회지
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• 제33권2호
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• pp.246-253
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• 2007

All of the machines in a production line can be classified into bottleneck and non-bottleneck machines. A bottleneck is a resource whose capacity limits the throughput of the whole production facility. This paper addresses a batch sizing problem at the bottleneck machine. Traditionally, most batch sizing decisions have been made based on the EOQ (economic order quantity) model where setup and inventory costs are considered while throughput rate is assumed to be given. However, since batch size affects the capacity of the bottleneck machine, the throughput rate may not be constant. As the batch size increases, the frequency of the setup decreases. The saved setup time can be transferred to processing time, which results in higher throughput. But, the larger batch size may also result in longer lead time and larger WIP inventory level. This paper presents an alternative method to determine batch size at the bottleneck machine in a manufacturing line. A linear search algorithm is introduced to find optimal throughput rate and batch size at the same time. Numerical examples are provided to see how the proposed method works and to investigate the effects of some parameters.

• 제어로봇시스템학회논문지
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• 제18권9호
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• pp.854-862
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• 2012

The optimal design of batch-storage network by using periodic square wave model provides analytical lot sizing equations for a complex supply chain network characterized as multi-supplier, multi-product, multi-stage, non-serial, multi-customer, cyclic system including recycling and/or remanufacturing. The network structure includes multiple currency flows as well as material flows. The processes are represented by multiple feedstock/product materials with fixed composition which are very suitable for production processes. In this study, transportation processes that carry multiple materials with unknown composition are added and the time frame is changed from single period into multiple periods in order to represent nonperiodic parameter variations. The objective function of the optimization involves minimizing the opportunity costs of annualized capital investments and currency/material inventories minus the benefit to stockholders in the numeraire currency. The expressions for the Kuhn-Tucker conditions of the optimization problem are reduced to a multiperiod subproblem for average flow rates and analytical lot-sizing equations. The multiperiod lot sizing equations are different from single period ones. The effects of corporate income taxes, interest rates and exchange rates are incorporated.

• 한국정밀공학회지
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• 제22권6호
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• pp.135-143
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• 2005

The shoes process management monitoring system for supporting SCM is developed in this study. This system consists of a monitoring program, a conveyer system, a pneumatic unit, a controller, an USB camera, and a server and a client computer. To operate the developed system easily, the monitoring program using LabVIEW in the Windows environment is developed. This program consists of 5 modules: production management, inventory control, media management, defective management, and communication management. The developed system has several advantages: reduced time for managing process work, decreased labor costs, effective operation, and continuous work without an operator. Nowadays advanced manufacturing companies are trying to find a way to check the performance of their production equipments and plants from remote sites. Thus, to manage the developed system from remote sites, communication network is constructed. In order to evaluate the performance of the monitoring system, experiments were performed. The experimental results showed that the developed system provided a reliable performance and a stable communication.

• 경영과정보연구
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• 제26권
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• pp.27-60
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• 2008

Researches on the introduction of ERP system kept on examining the critical successful factors (CSFs) that focus on factors to achieve effectively successful projects, and trying to measuring the actual effectiveness of the introduction of ERP system. However, most of the preceding researches on the effectiveness of the introduction of ERP system that was searching devoted effects has been ceased, and actually even researches on the economical results have just done the basic cognitive evaluation of result indicators by many questionnaires instead of objective measuring values, because of the difficulty of measuring the evaluation of the result. Moreover, researches on positive effects of the introduction of ERP on enterprise results and researches that failed to give advantageous effects showed different results each other. And a part of researches reported that only a part of result indicators were partially affected. In this research, we investigated Korean large enterprises or middle-sized enterprises in manufacture industry that introduces SAP R/3 and Oracle package to compare their quantitative financial results after the introduction of ERP system, in order to measure the effects of the ERP system. First, we evaluated the difference of the quantitative financial results before and after the introduction of the ERP system. Second, we evaluated the opportunities shown by the effects after the introduction of the ERP system. Third, we removed the sample of the exchange crisis (IMF) and executed the additional analysis to reflect the average increasing and decreasing rate in the industry, so that pure evaluation can be achieved. Inherent limits of precedent researches are removed and practical effects of the pure introduction of the ERP system are evaluated, so the research of this research is significant. The result of this research is as follows. Because of the introduction of ERP, the rate of turnover of inventory property has increased and sales of preparation inventory property have decreased so that more effective inventory property management has been achieved. Moreover, preparation sales of labor costs and preparation sales of the number of employees have decreased to show the effect of the reduction of labor costs. However, it could no be concluded that we could increase the profit due to the introduction of ERP system. Due to the introduction of ERP, although we concluded that the return on assets (ROA) and the additional value of one-person employee statistically showed obvious differences and increased, the return on equity failed to show obvious differences after the process of introduction of ERP.

• Journal of Preventive Medicine and Public Health
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• 제19권2호
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• pp.213-223
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• 1986

Ratio analysis allows a hospital to evaluate its own performance over time and to compare its performance with that of other hospitals. For this study, three types of ratio analysis were conducted based on some data on hospitals in Massachusetts. First, Key ratios influencing financial performance were identified using discriminant analysis. Second, the financial structures of the teaching and the non-teaching hospitals were compared using ratios and multiple comparison method. Third, the effects of the prospective reimbursement law of the state on financial performance were examined using ratios and paired t-test. The purpose of the law is to reduce hospital costs by setting the revenue ceiling prior to the effective budget year. The findings of this study were as follows: 1) When hospitals were divided into three groups, according to their operating income, only profitability ratios showed a consistent difference among the groups. 2) In the discriminant analysis, five ratios were selected: current ratio, operating margin, return on assets, fixed assets turnover, and inventory turnover. They are the key ratios to be monitored periodically for the purpose of evaluating the financial performance of hospitals. 3) When teaching hospitals were compared with non-teaching hospitals, acid ratio, days of cash on hand, and inventory turnover were statistically significant before the law went into effect, whereas only fixed assets turnover and inventory turnover were significant afterward. Contrary to previous studies, profitability ratios of teaching hospitals were higher than those of non-teaching hospitals, although the differences were not statistically significant. 4) When the ratios between the two periods (before and after the law) were compared, three profitability ratios (operating margin, return on assets, and return on equity) were significant for teaching hospitals, whereas three activity ratios (total assets turnover, fixed assets turnover, current assets turnover) were significant for non-teaching hospitals. Furthermore, while both total operating revenue and expenses were decreased, net operating income was increased, due to a greater decrease in total operating expenses. This shows that the law can indeed, simultaneously, achieve both a reduction in costs as well as an improvement in the financial situation of hospitals.

• 한국산림과학회지
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• 제97권4호
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• pp.445-451
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• 2008

본 연구는 Tablet PC를 기반으로 정밀수치임상도 제작을 위한 현장조사용 맞춤형 시스템을 개발하는데 그 목적이 있다. 본 연구에서 개발한 FIS의 주요 개발내용 및 특징은 다음과 같다. FIS는 GPS에서 수신한 정보를 바탕으로 다양한 공간 Data에서 위치정보를 쉽게 파악할 수 있어 정보의 접근성이 용이한 장점이 있다. 또한 임상편집 뿐만 아니라 메모 및 야장도구를 통해 여러 가지 정보들을 현장에서 손쉽게 기록하고 관리할 수 있으며, 간단한 측정도구로 거리와 면적을 쉽게 산출할 수 있다. 본 연구에서 개발한 시스템을 활용하여 효율적인 현장조사가 가능하므로 현장에서 시간 및 비용을 절감할 수 있으며, 현장작업의 생산력이 향상될 것이다.