• Nuclear Engineering and Technology
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• v.19 no.4
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• pp.233-241
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• 1987

Difficulties are encountered when the behavior of complex systems (i.e., fuel failure probability) that have unreliable deterministic models is predicted. For more realistic prediction of the behavior of complex systems with limited observational data, the present study was undertaken to devise an approach of combining predictions from the deterministic model and actual observational data. Predictions by this method of combining are inferred to be of higher reliability than separate predictions made by either model taken independently. A systematic method of hierarchical pattern discovery based on the method developed in the SPEAR was used for systematic search of weighting factors and pattern boundaries for the present method. A sample calculation was performed for prediction of CANDU fuel failures that had occurred due to power ramp during refuelling process. It was demonstrated by this sample calculation that there exists a region of feature space in which fuel failure probability from the PROFIT model nearly agree with that from observational data.

• Journal of the Korean Regional Science Association
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• v.36 no.1
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• pp.37-50
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• 2020

Estimating investment profits of real estate is critical to understand real estate markets and create relevant policy as real estate market and capital market combines closely. Thus, this study applied the concept of Tobin's Q to estimate investment profits for apartments as well as row-houses and multi-family homes in Seoul from 2010 to 2018. Investment profits were estimated by two approaches: subtracting the replacement cost from the transaction price and calculating ratio of the transaction price to the replacement cost, respectively. The spatio-temporal changes in investment profits were apparent in apartments compared with row-houses and multi-family homes. As a result of analyzing the spatial econometrics models, the investment profit was higher in the area with high density and new developments regardless of the housing types. The framework and key findings would be the effective reference to understand residential investment behavior, create relevant housing policy, introduce value capture of windfall, measure regional competitiveness, and estimate housing bubble.

• Journal of Convergence for Information Technology
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• v.11 no.3
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• pp.125-131
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• 2021

The problem of determining the maintenance point which minimizes the process-related total cost is called the 'process mean shift problem'. By expanding and integrating the existing maintenance models that have been partially progressed, we present a expanded and integrated maintenance model which reflects the production site where various situations occur. To implement this, we set both the upper and lower limits of the product specification, and adopted the quality loss function for conforming items. Also, we set the process variance of the wear level as a function rather than a constant. In this study, we developed two general functions to the wear level. One is about the production volume and the other is maintenance cost. As a result, this study is expected to be a maintenance model that can be applied to various processes. In the future, this study can be developed as a profit maximization model by adding profit items from product sales, and expansion to a maintenance model that introduces failure to the model of this study can be considered.

• Journal of Intelligence and Information Systems
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• v.24 no.3
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• pp.157-176
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• 2018

The purpose of this research is to develop a detection model for companies designated as administrative issue in KOSDAQ market using financial data. Administration issue designates the companies with high potential for delisting, which gives them time to overcome the reasons for the delisting under certain restrictions of the Korean stock market. It acts as an alarm to inform investors and market participants of which companies are likely to be delisted and warns them to make safe investments. Despite this importance, there are relatively few studies on administration issues prediction model in comparison with the lots of studies on bankruptcy prediction model. Therefore, this study develops and verifies the detection model of the companies designated as administrative issue using financial data of KOSDAQ companies. In this study, logistic regression and decision tree are proposed as the data mining models for detecting administrative issues. According to the results of the analysis, the logistic regression model predicted the companies designated as administrative issue using three variables - ROE(Earnings before tax), Cash flows/Shareholder's equity, and Asset turnover ratio, and its overall accuracy was 86% for the validation dataset. The decision tree (Classification and Regression Trees, CART) model applied the classification rules using Cash flows/Total assets and ROA(Net income), and the overall accuracy reached 87%. Implications of the financial indictors selected in our logistic regression and decision tree models are as follows. First, ROE(Earnings before tax) in the logistic detection model shows the profit and loss of the business segment that will continue without including the revenue and expenses of the discontinued business. Therefore, the weakening of the variable means that the competitiveness of the core business is weakened. If a large part of the profits is generated from one-off profit, it is very likely that the deterioration of business management is further intensified. As the ROE of a KOSDAQ company decreases significantly, it is highly likely that the company can be delisted. Second, cash flows to shareholder's equity represents that the firm's ability to generate cash flow under the condition that the financial condition of the subsidiary company is excluded. In other words, the weakening of the management capacity of the parent company, excluding the subsidiary's competence, can be a main reason for the increase of the possibility of administrative issue designation. Third, low asset turnover ratio means that current assets and non-current assets are ineffectively used by corporation, or that asset investment by corporation is excessive. If the asset turnover ratio of a KOSDAQ-listed company decreases, it is necessary to examine in detail corporate activities from various perspectives such as weakening sales or increasing or decreasing inventories of company. Cash flow / total assets, a variable selected by the decision tree detection model, is a key indicator of the company's cash condition and its ability to generate cash from operating activities. Cash flow indicates whether a firm can perform its main activities(maintaining its operating ability, repaying debts, paying dividends and making new investments) without relying on external financial resources. Therefore, if the index of the variable is negative(-), it indicates the possibility that a company has serious problems in business activities. If the cash flow from operating activities of a specific company is smaller than the net profit, it means that the net profit has not been cashed, indicating that there is a serious problem in managing the trade receivables and inventory assets of the company. Therefore, it can be understood that as the cash flows / total assets decrease, the probability of administrative issue designation and the probability of delisting are increased. In summary, the logistic regression-based detection model in this study was found to be affected by the company's financial activities including ROE(Earnings before tax). However, decision tree-based detection model predicts the designation based on the cash flows of the company.

• The Korean Journal of Applied Statistics
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• v.28 no.3
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• pp.429-442
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• 2015

Volatility forecasting in financial markets is an important issue because it is directly related to the profit of return. The volatility is generally modeled as time-varying conditional heteroskedasticity. A generalized autoregressive conditional heteroskedastic (GARCH) model is often used for modeling; however, it is not suitable to reflect structural changes (such as a financial crisis or debt crisis) into the volatility. As a remedy, we introduce the Markov regime switching GARCH (MRS-GARCH) model. For the empirical example, we analyze and forecast the volatility of the daily Korea Composite Stock Price Index (KOSPI) data from January 4, 2000 to October 30, 2014. The result shows that the regime of low volatility persists with a leverage effect. We also observe that the performance of MRS-GARCH is superior to other GARCH models for in-sample fitting; in addition, it is also superior to other models for long-term forecasting in out-of-sample fitting. The MRS-GARCH model can be a good alternative to GARCH-type models because it can reflect financial market structural changes into modeling and volatility forecasting.

• Journal of Intelligence and Information Systems
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• v.16 no.2
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• pp.1-17
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• 2010

Association rules among product items by association analysis suggest sales effect among products. These are useful for marketing strategies such as cross-selling and product display etc. However, if we evaluate more practical product values reflecting cross-selling effects, they will be also more useful for the decisions of companies such as product item selection for product assortment and profit maximization etc. This study proposes product value evaluation models with the concept of effective value based on single-item association chain and itemset association chain. In addition to that, we performed experiments with transaction data related to clothing of an online shopping mall in Korea to show the performances of our models. In result, we confirmed that some items increased in effective values compared with their pure values while the others decreased in effective values.

• Journal of Space Technology and Applications
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• v.1 no.2
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• pp.178-198
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• 2021

The Solar Space Environment Division of the Korean Society of Space Science (KSSS) has recently conducted a survey among the domestic researchers affiliated with academia, national research institutes, and for-profit institutes of how the data and models in their professional research field are produced, maintained, and utilized. The primary purpose of this survey is to increase the awareness and utilization of the space environment data and models as well as to promote constructive collaborations among the domestic and international researchers. The models and data surveyed are categorized into three sub-fields: the solar and interplanetary space, the (terrestrial) magnetosphere, and the ionosphere and upper atmosphere. The present paper reports the survey results in the "Magnetosphere" category. The survey shows that the domestically produced data in this category are far less than the data produced in other categories. This can be understood in part as follows: Magnetospheric research relies heavily on the in-situ observations but the development and operation of space-hardened satellites require a significant investment. Nevertheless, the recent publications show an increasing trend of research using the data from the ground stations and the recently launched domestic space missions. In the modeling front, there are first-principles physics models covering from the magnetospheric scale to the sub-ion scale and the models geared towards the space weather prediction. The detailed survey results can be accessed from the KSSS website (http://ksss.or.kr/).

• The KIPS Transactions:PartD
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• v.17D no.5
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• pp.371-382
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• 2010

One of the advantages of the mobile internet is that it is accessible everywhere. However, producing the mobile internet contents is hard because the standards of the contents are different depending on the telecommunications companies and the mobile phone terminals. Because of this, mobile contents production has not been activated and profit models are rarely found. In order to vitalize the mobile contents, we developed the Mobile UCC (User Created Contents) Phone Page Service with which general users can produce and provide the mobile phone pages easily. In addition, we began to provide advertisement on the UCC phone pages as a profit model. However, as mentioned already, the contents that meet each of the standards should be prepared in advance to be compatible with the different standards. For this reason, only one advertisement could be provided on one UCC phone page. Previous studies were focused on the standardization of different standards by integrating them. Though the standardization may be applicable to the mobile phones that will be newly released, it is hardly applied to the conventional mobile phones. To solve the abovementioned problems and improve the drawbacks of the conventional studies, we proposed in this article the technology to synthesize the phone page contents and independent advertisement at the moment when the UCC phone page prepared by the users is provided in real time. This technology allows to provide various advertisement on one UCC phone page and administrate the start, end and frequency of specific advertisements. This method was applied in this study to vitalize the mobile contents and improve the profit model.

• Journal of Distribution Science
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• v.13 no.10
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• pp.109-114
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• 2015

Purpose - The movie market has the characteristics of being a perfectly competitive market as well as a pure monopolistic market at the same time. This is because there are competitors in the industry but prices, although not fixed, have not changed a lot. Price competition may not have spread, but the competition is focused on artistic value, and the degree of box office success is most important. The artistic value is determined in the course of the production process. However, the degree of box office success is dependent upon the marketing manager. The marketing strategy represents the difference in the standard or quality of the movie. Inherently, the marketing manager adopts the entertainment strategy based on the quality of the foundation of the completed movie. At this time, the marketing manager knows the pertinent information (high quality/low quality) regarding the movie. This research study tries to reveal what should be the reasonable movie marketing expense, dependent on the quality of the movie. Research design, data, and methodology - Using a game scenario with different market players, the goal of the research analysis is to find out the following. First, the marketing expense is determined to maximize the profits after film production. Second, after the production costs are already committed, the manufacturer gets to choose the marketing level. At this time, there will be a profit maximization point, considering the competition. The premise of the research is as follows: if it is a good movie of quality, positive word of mouth increasing the audience continuously slows down the speed of the demand curve. If the movie quality is bad, the negative word of mouth decreasing the audience gradually hastens the speed of the demand curve. On the marketing side, when the manufacturer invests heavily in the marketing expense of the movie, consumer expectations increase to drive up the audience numbers. On the other hand, it is difficult to improve the profits excessively. When the manufacturer invests in marketing a little bit, the marketing expense is only relatively committed, therefore a lot of demand cannot be gained. Results - If a fixed market share is in a competitive situation, a low quality manufacturer expends relatively more marketing expense. If the situation assumes two manufacturers spend the same for the cost of production, the high quality manufacturer takes more profit. If the manufacturer expends less marketing budget to save costs, the optimum profit cannot be achieved since the other party (opponent) grabs the initial market share. Conclusions - In conclusion, investment is essential for market share to increase. We must refrain from a zero-sum game and have models where the game participants pursue the creative profits together. In the current film industry, there is the dominating logic of winner and loser but we have to create a film industry environment where the participants can be altogether satisfied and live together.

• Korea Journal of Hospital Management
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• v.7 no.4
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• pp.1-23
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• 2002

This study examined the influence of the separation of prescribing and dispensing roles(SPD) policy implemented in Korea in July 2000, especially on the change in the net profit of medical institutions. Using the data set from the Korea's National Health Insurance and the previous research, this study elicited the following main results. First, tertiary care institutions was estimated to lose about 631 billion won after the SPD policy. Second, general hospitals and hospitals gained about 557 billion and 564 billion won, respectively. Third, it is shown that clinics also gained 389-659 billion won. Finally, however, the change in net profit of medical institutions after the SPD policy largely depends on different estimation models. Moreover, it also varies from the assumptions on the price differential of a reimbursable drug which worked as cross-subsidy to insufficient physician's fee before the SPD policy. Despite such limitations as lack of data outside of the National Health Insurance's coverage, this study differs from others. This is the first research to explore the effect of the SPD policy on different types of medical institutions and to attempt to purely focus on the SPD policy. In this study, we can draw the policy implication that preparing for a policy change, the government should set up the policy evaluation system to collect the concerned data and develop the methodologies in advance to the policy implementation.