• Journal of Korea Game Society
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• v.18 no.1
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• pp.95-104
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• 2018

This study analyzes the system of Loot Box in Overwatch, FPS genre game produced by an American company Blizzard. Currently, one of the most controversial issues in the recent industry is "Probability-Type Item" that game users purchase high-end game items as a form of lottery. As this study examines a foreign case of Loot Box that is similar to Probability-Type Item, it would show how it is constructed and does legal approaches. Throughout this, it not only analyzes pros and cons of the Loot Box system, but also provides thought-provoking messages for the issue of the Probability-Type Item.

• The Journal of Korean Association of Computer Education
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• v.23 no.1
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• pp.29-36
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• 2020

Various items were used as evaluation tools that identify the student's abilities accurately to confirm the completion of learning. Among them, the multiple choice item has the advantages of high objectivity and reliability in scoring, but it cannot remove the factor of guessing. In this paper, the multiple choice items are classified into two types according to the relationship between the questionnaire and the choices. One is the type used in the classical test theory with the probability of guessing 1/k for k choices and the other is the novel proposed type which introduces the concept of partial knowledge. In the proposed type, the probability of guessing when the number of knowledge i is (i+1)/k for k choices. Based on the assumptions of the previous theories about multiple choice items, we derive the guessing parameter about the proposed type. And we analyzed the effect of the guess on the correct answer in the existing type and the proposed type. This shows that the proposed type has more question guessing than the existing type.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.60
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• pp.11-22
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• 2000

The main objective of this research is to analyze an order point and an order quantity of a distribution center and each branch to attain a target service level in multi-level inventory distribution system. In case of product item, we use the item with low volume of average monthly demand. Under the continuous review method, the distribution center places a particular order quantity to an outside supplier whenever the level of inventory reaches an order point, and receives the order quantity after elapsing a certain lead time. Also, each branch places an order quantity to the distribution center whenever the level of inventory reaches an order point, and receives the quantity after elapsing a particular lead time. When an out of stock condition occurs, we assume that the item is backordered. For considering more realistic situations, we use generic type of probability distribution of lead times. In the variable lead time model, the actually achieved service level is estimated as the expected service level. Therefore, this study focuses on the analysis of deciding the optimal order point and order quantity to achieve a target service level at each depot as a expected service level, while the system-wide inventory level is minimized. In addition, we analyze the order level as a maximum level of inventory to suggest more efficient way to develop the low demand item model.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.85-86
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• 2018

최근 들어 가챠 시스템이 없는 게임을 찾기 어려울 만큼 많은 게임들이 가챠 시스템을 사용하고 있다. 그중에서도 가챠 시스템이 메인 콘텐츠라고 할 수 있을 만큼 큰 비중을 차지하고 있는 게임이 있고, 반대로 메인 콘텐츠가 따로 있어 부가적인 요소로 사용하는 게임이 있다. 본 연구에서는 현재 게임에서 사용되고 있는 가챠 시스템의 현황과 규제 및 개발사의 대안에 대해 알아보고, 이로 인해 생기는 문제점을 분석한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.209-211
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• 2022

국내 게임 시장 규모는 2021년 21조원을 넘으며 시장이 빠르게 성장하고 있다. 이러한 매출 규모에 큰 비중을 차지하는 상품은 확률형 가챠 아이템이 매출에 많은 부분을 담당하고 있다. 본 논문에서는 현재 게임 산업에서 사용되는 가챠 시스템에 대한 문제점을 소개하고 한계선이 없는 가챠 시스템에 대한 내용을 제시하면서, 최근 업계에서 한계선이 없는 가챠에 대한 대처법으로 출시하고 있는 천장 시스템에 대하여 소개와 천장 시스템의 성공 사례 및 앞으로 천장 시스템이 어떤 방향으로 개선 되야하는지에 대한 내용을 제시한다.

• The Korean Journal of Applied Statistics
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• v.21 no.1
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• pp.95-107
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• 2008

Survey on the rural living indicators was the statistic approved from National Statistical Office and the survey executed by rural resources development institute. This study was used the raw data of survey on the rural living indicators in 2005. After editing procedure for raw data, we were studied 1,582 households which is acquired through elimination of case included nonresponses, and imputed a nonresponses of 15 item selected from 146 item. The imputation methods and efficiency of imputation for simulation was adapted differently from type of data. For continuous data, we imputed the nonresponses with mean imputation, regression imputation, adjusted grey-based k-NN imputation(DU, DW, WU, WW) and compared the results with RMSE. For categorical data, we imputed the nonresponses with mode method, probability imputation, conditional mode method, conditional probability method, hot-deck imputation, and compared the results with Accuracy. By the results, regression imputation and adjusted grey-based k-NN imputation appropriated for continuous data and hot-deck imputation appropriated for categorical data.

• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.2
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• pp.35-51
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• 2016

This paper proposes a new approximate approach to calculate the order fill rate and the probability of filling an entire customer order immediately from the shelf in a business environment under purchase dependence characterized by customer purchase patterns observed in such areas as marketing, manufacturing systems, and distribution systems. The new approximate approach divides customer orders into item orders and calculates fill rates of all order types to approximate the order fill rate. We develop a greed iterative search algorithm (GISA) based on the Gauss-Seidel method to avoid dimensionality and prevent the solution divergence for larger instances. Through the computational analysis that compares the GISA with the simulation, we demonstrate that the GISA is a dependable algorithm for deriving the stationary joint distribution of on-hand inventories in the type-K pure system. We also present some managerial insights.

• Korean Management Science Review
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• v.31 no.2
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• pp.1-13
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• 2014

In almost all of the organizations, the cost for acquiring and maintaining the inventory takes a considerable portion of the management budget, and thus a certain constraint is set upon the budget itself. The previous studies on inventory control for each item that aimed to improve the fill rate, backorder, and the expenditure on inventory are fitting for the commercially-operated SCM, but show some discrepancies when they are applied to the spare parts for repairing disabled systems. Therefore, many studies on systematic approach concept considering spare parts of various kinds simultaneously have been conducted to achieve effective performance for the inventory control at a lower cost, and primarily, METRIC series models can be named. However, the past studies were limited when dealing with the probability distributions for representing the situation on demand and transportation of the parts, with the (S-1, S) inventory control policy, and so on. To address these shortcomings, the Continuous Time Markov Chain (CTMC) model, which considers the phase-type distributions and the (s, Q) inventory control policies to best describe the real-world situations inclusively, is presented in this study. Additionally, by considering the cost versus the system availability, the optimization of the inventory level, based on this model, is also covered.

• Journal of the Korean Data and Information Science Society
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• v.25 no.6
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• pp.1591-1598
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• 2014

The reviews of the balance sheet of commercial banks showed that loan item constitutes the largest portion of bank's assets. Although the sector has highest rate of profit, it possesses the greatest risk. Identifying factors that can contribute in lifting-up the loan repayment rate of customers of Hawassa district commercial bank is the major goal of this study. A sample of 183 customers who took loan from October, 2005 to April, 2012 was taken from the bank record. Kaplan-Meier estimation method and univariate Cox proportional hazard model were applied to identify factors affecting bank loan repayment rate. The result from Kaplan-Meier survival estimation revealed that the loan repayment rate is significantly related with loan type, and previous loan experience, educational level and mode of repayment. The log-rank test indicates that the survival probability of loan customers is not statistically different in repaying the loan among groups classified by sex. Moreover, the univariate Cox proportional hazard model result portrayed that educational level, having previous loan experience, mode of repayment, collateral type and purpose of loan are significantly related with loan repayment rate of customers commercial bank. Hence, banks should design loan strategies giving special emphasis on the significant factors while they are giving loans to their customers.

• Journal of the Korean Society of Costume
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• v.63 no.3
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• pp.17-32
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• 2013

This study examined the visual elements of the Trompe l'oeil design and the combination conditions of each element in order to deduce the form generation diagrams of Trompe l'oeil fashion design. The following is what the study found: First, Trompe l'oeil fashion design can be divided into two based on its subject: 'the combination of internal elements of dress' and 'the combination of external elements of dress'. Looking at the visual components of each type, depending on the subject, 'the combination of internal elements of dress' design was achieved by combining internal dress elements: including textile, detail, item, accessory, layering, etc.. In case of 'the combination of external elements of dress' design, the object of Trompe l'oeil was expanded in scope to environment, which includes the actions of a wearer. Second, as for Trompe l'oeil fashion design through the combination of external dress elements, the condition to combined visual components of the work in the process of creation was related to 'the popularity of object', 'the similarity of shapes and sizes', and 'the probability of location'. Third, deriving a form generation diagrams of Trompe l'oeil fashion design was very effective in delineating specific relationships and conditions, directions among elements combined in fashion design.