• Journal of Korean Institute of Industrial Engineers
• /
• v.22 no.3
• /
• pp.473-483
• /
• 1996

For situations where there are several markets with different price/cost structures, economic complete inspection plans are developed for determining the market to ship the product to. Two complete inspection plans are considered; the plan based on the performance variable of interest, and the plan based on a variable which is correlated with the performance variable. Profit models are constructed which involve selling price, cost incurred by imperfect quality, and quality inspection cost. Methods of finding the optimal complete inspection plans are presented and a numerical example is given.

• International journal of advanced smart convergence
• /
• v.12 no.1
• /
• pp.18-30
• /
• 2023

We compared empirically the forecast accuracies of the LSTM model, and the ARIMA model. ARIMA model used auto.arima function. Data used in the model is 100 days. We compared with the forecast results for 50 days. We collected the stock closing prices of the top 4 companies by market capitalization in Korea such as "Samsung Electronics", and "LG Energy", "SK Hynix", "Samsung Bio". The collection period is from June 17, 2022, to January 20, 2023. The paired t-test is used to compare the accuracy of forecasts by the two methods because conditions are same. The null hypothesis that the accuracy of the two methods for the four stock closing prices were the same were rejected at the significance level of 5%. Graphs and boxplots confirmed the results of the hypothesis tests. The accuracies of ARIMA are higher than those of LSTM for four cases. For closing stock price of Samsung Electronics, the mean difference of error between ARIMA and LSTM is -370.11, which is 0.618% of the average of the closing stock price. For closing stock price of LG Energy, the mean difference is -4143.298 which is 0.809% of the average of the closing stock price. For closing stock price of SK Hynix, the mean difference is -830.7269 which is 1.00% of the average of the closing stock price. For closing stock price of Samsung Bio, the mean difference is -4143.298 which is 0.809% of the average of the closing stock price. The auto.arima function was used to find the ARIMA model, but other methods are worth considering in future studies. And more efforts are needed to find parameters that provide an optimal model in LSTM.

• Journal of Navigation and Port Research
• /
• v.41 no.2
• /
• pp.63-70
• /
• 2017

Despite the remarkable continual growth of the world cruise industry, studies have yet to be attempted on many revenue management problems in cruise operations. This paper suggests two schemes that can be easily applied to cruise revenue management: optimal dual pricing and passenger safety level. In optimal dual pricing, a pair of higher and lower prices is applied to cabin reservation through market segmentation. This scheme can be executed with a linear price-response function for the current unreserved cabins. A cruise line could benefit from this scheme to maximize reservation revenue while attaining full occupancy. The dual pricing scheme is also devised to produce only integer demands to suit real management practices. The life boat capacity is an additional service capacity unique to the cruise industry, catering to passengers' safety. The concept of passenger safety level is defined and computed for any passenger life boat capacity of a cruise ship. It can be used to evaluate the passenger safety of a cruise ship in operation, as well as to determine the number of life boat seats required for a new cruise ship. Hypothetical examples are used to illustrate the operation of these two schemes.

• Korea Journal of Hospital Management
• /
• v.18 no.2
• /
• pp.81-103
• /
• 2013

This study is to research cost accounting practice and to analyze propriety of patients' medical payment in artificiality kidney center. The researched cost datum of the year 2012 are as follows. - Hemodialysis medical treatment was reimbursed as much as 158,001 won in case of health insured patients, but payed-off as much as 135,810 won. - The average figure of the total hospitals and clinic center is 1,603,303 won, and one time cost of hemodialysis treatment is 154,487 won. Optimal treatment pay are suggested as follows. First, Regardless of the notified classification from MOHW(Ministry of Health and Welfare), 136,000 won of fixed price payment classification needs to be reclassified by patients, severity and tobe rearranged by fixed price payment system of hospitals. Second, Fixed payment code notified by the Ministry of Health and Welfare is recommended to be simplifies and to reflect according to contents of the medical treatment rendered to patients. Third, Establishment of artificial kidney center has to be risk managed because of its huge investment. Fourth, Cost analysis model has to be maintained as basis together with appropriate application of conversion index model mixed with SGR model.

• Korean Journal of Agricultural Science
• /
• v.24 no.2
• /
• pp.138-144
• /
• 1997

Korean agricultural and rural economics has been gotten more difficult through the introduction of economics system under the control of IMF before problems from open market system under WTO get to be settled. Export should be promoted to get the advantage of open market system and to get over today's economic crisis from shortage of foreign currency. Fortunately, Korea adjoins Japan that is largest importing country of agricultural products in a world, therefore Korean Agricultural products has advantage in export to Japan through open market system. Puyo tomato, specialized agricultural products in Chungman province, has been exported 42.2M/T to Japan from 1994 year to 1996 year. But such exported amount was so small that is less than a 1% of total tomato product in Puyo area. Reasons why export volume to Japan was so small were non standard commodities, non performance of export contract, unfavorable price condition, etc.. But it was major reason that missed optimal exporting period. Therefore this study is aimed at finding optimal period exporting Puyo mini tomato to Japan. According to result of analysis based on monthly price and carried quality data of major tomato market between Korea and Japan, it has more comparative advantage that we export tomato during Period of Dec-Feb. rather than March-May which is currently major exporting period.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.1
• /
• pp.51-59
• /
• 2018

Despite the advantages of energy arbitrage using energy storage systems (ESSs), the high cost of ESSs has not attracted storage owners for the arbitrage. However, as the costs of ESS have decreased and the price volatility of the electricity market has increased, many studies have been conducted on energy arbitrage using ESSs. In this study, the existing two-period model is modified in consideration of the ESS cost and risk-free contracts. Optimal investment strategies that maximize the sum of external effects caused by price changes and arbitrage profits are formulated by market participants. The optimal amounts of ESS investment for three types of investors in three different market structures are determined with game theory, and strategies in the form of the mixed-complementarity problem are solved by using the PATH solver of GAMS. Results show that when all market participants can participate in investment simultaneously, only customers invest in ESSs, which means that customers can obtain market power by operating their ESSs. Attracting other types of ESS investors, such as merchant storage owners and producers, to mitigate market power can be achieved by increasing risk-free contracts.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.8
• /
• pp.691-697
• /
• 2016

Remanufacturing refers to restoring a used product to an acceptable condition for resale in the market of remanufactured items. In this paper, we deal with the acquisition price and remanufacturing decision for remanufacturing systems in the case where the demand for the remanufactured product in a single period is known and the return quantity of the used product is determined by its acquisition price. The quality of the acquired used product is categorized into two classes, high and low, through inspection and different qualities incur different remanufacturing costs. The probability that the acquired used product is categorized as high class can be a constant or random variable. We derive the expected total cost functions, obtain the optimal solutions, and interpret the managerial meaning of the optimal solution for each case. The sensitivity of the optimal solution with respect to the variation of the inspection cost and uncertainty of the quality of the used product is investigated through numerical examples.

• The Journal of Society for e-Business Studies
• /
• v.17 no.2
• /
• pp.105-114
• /
• 2012

Recently, global warming, energy shortage, and environmental disruption have been serious problems in every nation. It became more and more important to reduce the emission of CO2 and to use of energy efficiently. Smart grid was also introduced using the rapidly developing information technology. It deployed the mutual communication concept between customers and the suppliers in the electricity supply. There were increasing demands to adopt the smart meter and to present incentive for efficient energy usage in many developed countries. The objective of this research was to develop the optimal real time pricing model which maximized the profit of the power retailer and reduced the usage of energy. The simulation study was given to show the usefulness of the model. Simulation considered the customer demand response rate and price elasticity rate. The price elasticity rate was compared in the condition of fixed value according to time and variable value according to the customers. The optimal price model could maximize the profit of the power retailer and reduce the energy usage of the consumers.

• International Journal of Internet, Broadcasting and Communication
• /
• v.13 no.2
• /
• pp.244-259
• /
• 2021

The economic value of personal information has its importance as an objective measure of valuation in commercial, legal, and policy areas. Until recently, however, personal information subjects have not properly recognized the economic value of personal information, which has led to the inability to exercise the right to self-determination of personal information by unconsciously agreeing to the terms and conditions of personal information service without recognizing the value of personal information provided to the service provider when subscribing to a specific service. Therefore, we will examine the methodologies for calculating the economic value of personal information and the practical guarantee of the right to self-determination of personal information and analyze the economic value of personal information through a survey. Also, we would like to propose various ways for the subject of personal information with limited cognitive resources to visually accept the economic value of personal information required by the terms and conditions and suggest the optimal visualization of personal information economic value to exercise the right to self-determination of personal information. To do so, in this paper, we have conducted two survey experiments to estimate the economic value of personal information. Based on the price of personal information by category retrieved from surveys, we have visualized the price of personal information in various forms and asked respondents to choose the optimal infographic that best represents the value of personal information visually. As a result, we have proposed an optimal usage of the infographic to 'nudge' information subjects about their right to self-determination of personal information, therefore opening the possibility of diminishing privacy paradox.

• Journal of Communications and Networks
• /
• v.18 no.6
• /
• pp.962-974
• /
• 2016

We are concerned with whether a vertically integrated broadband and content provider can unreasonably advantage itself over competing content providers, either by selling quality-of-service (QoS) to content providers at unreasonably high prices, or by refusing to provide access to QoS to competing content. We address this question by modeling the competition between one such vertically integrated provider and one over-the-top (OTT) content provider. The broadband provider decides whether to deploy QoS, and if so it also determines the QoS price if sold to either the OTT content provider or directly to users. We analytically determine when the broadband provider will sell QoS and when the OTT content provider or users will purchase QoS. We characterize the optimal QoS and video service prices. The Internet service provider (ISP)'s market share increases with the difference in the value of the two video services and decreases with the difference in the corresponding costs. Numerical results illustrate the effect of QoS price on content price, the variation of prices and profit with QoS price, and the variation of prices and market shares with the benefit of QoS. The ISP may sell QoS to users at a lower price than when QoS is sold to the OTT provider.