• Journal of Korean Society for Quality Management
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• v.37 no.3
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• pp.74-82
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• 2009

This article presents a six sigma project for improving purchase conversion rate in mobile game site. The project was carried out based on DMAIC process. First, a defect rate is defined as low purchase conversion rate. In addition, 60-days purchase data was analyzed and it is shown that the defects level was 2.48 sigma level. In this study, in order to raise the sigma level, six personalization services were used in the mobile game site. Six factors were determined based on FDPM(Functional Deployment Process Map), fishbone chart, linear regression analysis, effort-performance matrix, and so on. The sigma level of defects has improved from 2.48 to 2.93.

• Communications of Mathematical Education
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• v.21 no.4
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• pp.597-612
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• 2007

For finding the optimal strategy in Blackout game which was introduced in the homepage of popular movie "Beautiful mind", we have developed and generalized a mathematical proof and an algorithm with a couple of softwares. It did require only the concept of basis and knowledge of basic linear algebra. Mathematical modeling and analysis were given for the square matrix case in(Lee,2004) and we now generalize it to a generalized $m{\times}n$ Blackout game. New proof and algorithm will be given with a visualization.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.46
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• pp.51-58
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• 1998

In this paper a bimatrix game with imprecise values in its matrix of payoffs is considered. We propose a method for its solution based on the establishment of a linear complementary problems for two players. To solve the problems we use the auxiliary models resulting from the methods for ranking fuzzy numbers.

• Journal of Korea Game Society
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• v.13 no.5
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• pp.43-54
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• 2013

With the consistent development of the 3D application technique, visuals are available at more realistic quality and are utilized in many applications like game. In particular, interacting with 3D objects in virtual environments, 3D graphics have led to a substantial development in the augmented reality. This study proposes a 3D user interface to control objects in 3D space through virtual two-view method using only one camera. To do so, homography matrix including transformation information between arbitrary two positions of camera is calculated and 3D coordinates are reconstructed by employing the 2D hand coordinates derived from the single camera, homography matrix and projection matrix of camera. This method will result in more accurate and quick 3D information. This approach may be advantageous with respect to the reduced amount of calculation needed for using one camera rather than two and may be effective at the same time for real-time processes while it is economically efficient.

• Proceedings of the KIEE Conference
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• summer
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• pp.710-712
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• 2004

Generation companies(Genco) submit the supply functions as a bidding function to a bid market in a competitive electricity market. The profits of Gencos vary in accordance with the bid functions, so the selection of a bidding function plays a key role in increasing their profits. This paper presents an analysis of the selection of the supply function from the viewpoint of Nash equilibrium(NE). Four types of bidding function parameters are used for analizing the electricity market. The competition of selecting bidding parameters is modeled as subgame and overall game in this research. The NEs in both game are computed by using analytic method and payoff matrix method. It is verified in case studies for the NE of overall game to satisfy the equilibrium condition.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.768-770
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• 2013

We propose a symmetric key based cryptography algorithm to encode and decode the text data with limited length using 3-dimensional magic square matrix. To encode the plain text message, input text will be translated into an index of the number stored in the key matrix. Then, Caesar's shift with pre-defined constant value is fabricated to finalize an encryption algorithm. In decode process, Caesar's shift is applied first, and the generated key matrix is used with 2D magic squares to replace the index numbers in ciphertext to restore an original text.

• Journal of Korea Multimedia Society
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• v.12 no.6
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• pp.785-793
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• 2009

This paper proposes a signature using dominant singular values for video sequence matching. By considering the input image as matrix A, a partition procedure is first performed to separate the matrix into non-overlapping sub-images of a fixed size. The SVD(Singular Value Decomposition) process decomposes matrix A into a singular value-singular vector factorization. As a result, singular values are obtained for each sub-image, then k dominant singular values which are sufficient to discriminate between different images and are robust to image size variation, are chosen and normalized as the signature for each block in an image frame for matching between the reference video clip and the query one. Experimental results show that the proposed video signature has a better performance than ordinal signature in ROC curve.

• Journal of Korea Game Society
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• v.11 no.2
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• pp.13-18
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• 2011

Sid Meier said, "A game is a series of interesting choices." This means the interesting choices make the game funny. In this paper, we define the no interesting options in the gameplay as strategic errors of the gameplay and suggest a detection method of these errors of the gameplay. The suggested method detects the strategic errors of the gameplay by the inspection of the payoff matrices. This method can detect the options of no strategies of the opponent, dominant options, dominated options, similar options with almost same payoffs in the case of the inspection of the payoff matrices. Additionally it can detect the options of the expected payoff with excessively high, the options of the expected payoff with excessively low, the options of the usage probability with excessively high, and the options of the usage probability with excessively low in the case of the inspection of the payoff matrices with the corresponding frequency rates.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.4
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• pp.77-83
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• 2013

This study is to develop a mathematical analysis model to grasp the behaviors of cartels. Cartels are formed tacitly and cause tremendous damage to consumers in modern society which is composed of advanced industry structure. The government authorities have instituted the leniency programs to respond cartels. However, cartels will continue unless there are legal sanctions against cartels based on an accurate analysis of leniency programs. The proposed cartel equilibrium analysis model is a mathematical behavior model which is based on the existing methods and the prison's dilemma of game theory. Therefore, the model has a form of pay off matrix of two players. We use a iterated polymatrix approximation (IPA) method to deduct a Nash equilibrium point. The model is validated by an empirical analysis as well.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.10
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• pp.616-623
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• 2003

Competition among electric generation companies is a major goal of restructuring in the electricity industry, The trading system in an electricity market has been one of the most important issues in deregulated electricity market. This paper deals with comparisons of the major two types of the trading system: compulsory pool market and bilateral contract market. The two trading systems are compared quantitatively from the viewpoint of consumer's surplus and social welfare, This paper, also, proposes a unified model of Cournot and Bertrand for analyzing the mixed trading system of pool market and bilateral contract market. Nash equilibrium of the unified model is derived by criteria for participating in bilateral contract market. Numerical results from a sample case show that a mixed trading system of pool market and price-competitive bilateral market is beneficial to consumer from the view points of consumer's surplus.