• Journal of the Korean Data and Information Science Society
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• 제27권6호
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• pp.1661-1671
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• 2016

Risk analysis is a systematic study of uncertainties and risks we encounter in business, engineering, public policy, and many other areas. Value at Risk (VaR) is one of the most widely used risk measurements in risk management. In this paper, the Korean Composite Stock Price Index data has been utilized to model the VaR employing the classical ARMA (1,1)-GARCH (1,1) models with normal, t, generalized hyperbolic, and generalized pareto distributed errors. The aim of this paper is to compare the performance of each model in estimating the VaR. The performance of models were compared in terms of the number of VaR violations and Kupiec exceedance test. The GARCH-GPD likelihood ratio unconditional test statistic has been found to have the smallest value among the models.

• 대한산업공학회지
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• 제25권3호
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• pp.336-341
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• 1999

The problem of jointly determining the optimum process mean and screening limits for each market is considered in situations where there are several markets with different price/cost structures. The quality characteristic is assumed to be a normal distribution with unknown mean and known variance. A quadratic loss function is utilized for developing the economic model. Methods of finding the optimum process mean and screening limits are presented and a numerical example is given.

• 한국경영과학회지
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• 제1권1호
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• pp.139-145
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• 1976

To evaluate the composite composed of Shell-Oil Co. itself and its sub-sidiary companies, the account data for 10 years from 1964 to 1973 was analyzed. Before analyzing, the formula needed to it was deduced and by synthesizing the deduced formula, the price earning ratio (R) was computed as the trial and error method. Resultantly the earning power (ic) was less than 5% ie. R=17.03. So this company showed the normal company earnings and allotment from 1964 to 1968. From 1968 to 1970, the allotment was increased but the earnings was decreased. And in spite of the successive increase of the allotment from 1970 to 1973, the company showed that it was the stable and profitable one with stable increase of earnings. In conclusion, this company showed the stable trend of increase in the allotment of earnings and earnings itself.

• 산업경영시스템학회지
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• 제33권3호
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• pp.10-21
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• 2010

Promotion system can be used as strategical management weapon to enhance the sales power. Planned order system has some similarities with promotion system to create purchasing power and to supply the service parts with low price on purpose. The only difference is whether it is prearranged event or not. The effectiveness of forecasting has increased with normal state of ordering process. However, the accuracy of forecasting has diminished with irregular state of ordering, such as demand occurrences by unexpected climate change or intended planned order by the company. A planned order system is examined through the process of computing the effectiveness on the basis of forecasting in this paper. And it is suggested that how to increase the accuracy of forecasting capability under the planned order system.

• 한국유통학회:학술대회논문집
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• 한국유통학회 2000년도 추계학술대회 발표논문집
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• pp.91-105
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• 2000

Results of a study of the coordination effect in stocking and promotional markdown policies for a supply chain consisting of a retailer and a discount outlet (DCO) are reported here. We assume that the products are sold in two consecutive periods: Normal Sales Period (NSP) and subsequent Promotional Sales Period (PSP). When managers in the two periods coordinate, they share information on the demand forecast and jointly decide the stocking quantity, markdown time schedule, and markdown price to maximize mutual profit. In the absence of coordination, decisions are decentralized to optimize the individual party's objective function. Optimal coordination policy for the retailer/DCO problem setting is analyzed, and the coordination policy is compared with the uncoordinated policy to explore factors that make coordination an effective approach.

• 품질경영학회지
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• 제28권2호
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• pp.161-175
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• 2000

The problem of jointly determining the optimum process mem and screening limits for each market is considered in situations where there are several markets with different price/cost structures. Two inspection procedures are considered; an inspection based on the quality characteristic of interest, and an inspection based on a surrogate variable which is highly correlated with the quality characteristic. The quality characteristic is assumed to be a normal distribution with unknown mean and known variance. A Taguchi's quadratic loss function is utilized for developing the economic model for determining the optimum process mean and screening limits. A numerical example is given.

• 산업경영시스템학회지
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• 제21권45호
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• pp.201-213
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• 1998

We address the problem of choosing the most economic mean value for an automatic filling operation on a production line through the sampling inspection. If quality characteristic of a unit is less than inspection specification then the goods is not accepted. Otherwise, it is accepted. The lots that the numbers of non-conforming units in a sample are larger than the allowable number of non-conforming units are rejected. The non-conforming units in the rejected lots are separated by the screening inspection. The non-conforming units separated are sold in discount price. We assume that quality characteristic is larger-the-better characteristic, the distribution of quality characteristic is normal distribution, and the standard deviation of the distribution is known. This paper presents total expected profit function model considering sales revenue, inspection costs, and material costs. The manufacturing process mean value maximizing total expected profit is determined, and the results of the process target value and total expected profit is analyzed as coefficients change.

• 농업과학연구
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• 제37권2호
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• pp.315-321
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• 2010

Decision-makings or the related policies regarding domestic grape production heavily depends upon the known market price data and official statistics periodically announced by government, at national level. However, usual adaption of the 'simple means' from these data may bring seriously biased decision-makings when the original data are biased, especially when the data are not convinced to be normal distributions to decision makers. In this regards, this study employs Monte Carlo simulation technique to overcome the limitations, based on the decision makers' subjective assumptions on the known data, and, tries to come up with flexible range of business information regarding grape-producing farm income. The approach used in this study also provides possibility that it may be useful when adapting subjective assumptions from various statistical distributions.

• 한국자기공명학회논문지
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• 제6권2호
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• pp.142-154
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• 2002

One of the oldest, still unsolved, and often ignored problems in magnetic resonance remains the issue of how to observe undistorted, normal one-dimensional spectra where the frequencies and their relative intensities represent faithfully the distribution of spins and sites in the sample within the magnet. Often distortions in these parameters are accepted, as the price of sensitivity enhancement, or because it is unclear just how these distortions might be avoided. Surprisingly enough, the problem is exacerbated by the use of modern techniques of pulsed Fourier transform NMR. Noise spectroscopy is an approach to solving the problem of distorted NMR spectra, which is largely under appreciated; it promises virtually "unlimited" distortionless bandwidths without costly hardware investments. Nonetheless, its exploitation remains limited. We will discuss why noise spectroscopy belongs in the arsenal of tricks spectroscopists should be aware of, show examples where its use is essential if accurate, quantitative NMR is to be expected, and discuss some recent approaches which extend its applicability yet further, particularly in solid state NMR and in applications to quadrupolar nuclear spins.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.100-106
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• 2000

Recently, the population of vehicles using LPG as fuel has been increasing due to relatively low fuel price and low tax. Although gasoline engine oils we usually used to lubricate LPG engines, some troubles such as oil thickening and TBN depletion were found in them under severe operating condition. In order to investigate the deterioration mechanism of lubricants in LPG engine, field trials were performed. The results from the field trials showed that the deterioration of oils in LPG engine is different from that in normal gasoline engine. LPG engine oil was deteriorated mainly through oxidation and nitration at high temperature rather than contamination of fuel combustion products.