• KIPS Transactions on Software and Data Engineering
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• v.4 no.11
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• pp.479-486
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• 2015

Model checking method is able to check all possible cases automatically and is applicable to specifications or design before actual implementation so that some critical systems have adopted this method actively. However, the current practice of software verification is largely dependant on basic methods such as manual testing because of lack of understanding about this rigorous method and high verification cost. In this paper we conducted an experimental research for the automated verification using the SPIN model checker on an online-game server to study the applicability of the technique in this domain. The results show that we could verify major features of the online-game server party system with 5~7 GB memory and within 10 minutes execution time, and also found a hidden system error that passed existing testing process. This result shows the possibility of rigorous and effective verification with reasonable cost in comparison to manual testing.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.17 no.1
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• pp.19-26
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• 2006

Objectives : The object of this study was to examine computer game playing patterns and psychopathologies related to computer game addiction in school-age children. Methods : The subjects were 533 elementary school students (4th to 6th grade) in Kangdonggu, Seoul. We evaluated computer playing patterns of all subjects using computer game playing pattern questionnaire, and determined the risk group of computer game addiction by internet game addiction scale score. We evaluated subscale score of K-CBCL from parents of all subjects, and conducted correlation analysis and logistic regression analysis between computer game addiction and subscale score of K-CBCL. Results : In 488 responders, 10.2% of started playing computer game in preschool age, and 67.2% started at low grade of elementary school. The mean frequency of computer game play per week was 3.66 days. Mean time spent playing computer games per day was 1.89 hours. 'Simply for fun' was the most common reason far playing computer games (40.8%). Male subjects showed statistically significant differences in age of starting computer game, frequency of computer game play per week, reasons for playing computer game and computer game addiction scale scores. There were significant correlations between computer game addiction scale scores and academic performance, somatic complaints, attention problems, and internalizing problems in K-CBCL. But In logistic regression analysis, only attention problems among K-CBCL subscales showed significant predictability to computer game addiction. Conclusion : Upper grade elementary school students experienced computer game playing at the very early age, and spend much time in playing computer games. There were significant correlation and predictability between computer game addiction and attention problems.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.988-991
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• 2020

다양한 실세계 응용 분야들에서 공동의 목표를 위해 여러 에이전트들이 상호 유기적으로 협력할 수 있는 행동 정책을 배우는 것은 매우 중요하다. 이러한 다중 에이전트 강화 학습(MARL) 환경에서 기존의 연구들은 대부분 중앙-집중형 훈련과 분산형 실행(CTDE) 방식을 사실상 표준 프레임워크로 채택해왔다. 하지만 이러한 다중 에이전트 강화 학습 방식은 훈련 시간 동안에는 경험하지 못한 새로운 환경 변화가 실전 상황에서 끊임없이 발생할 수 있는 동적 환경에서는 효과적으로 대처하기 어렵다. 이러한 동적 환경에 효과적으로 대응하기 위해, 본 논문에서는 새로운 다중 에이전트 강화 학습 체계인 C-COMA를 제안한다. C-COMA는 에이전트들의 훈련 시간과 실행 시간을 따로 나누지 않고, 처음부터 실전 상황을 가정하고 지속적으로 에이전트들의 협력적 행동 정책을 학습해나가는 지속 학습 모델이다. 본 논문에서는 대표적인 실시간 전략게임인 StarcraftII를 토대로 동적 미니게임을 구현하고 이 환경을 이용한 다양한 실험들을 수행함으로써, 제안 모델인 C-COMA의 효과와 우수성을 입증한다.

• The KIPS Transactions:PartD
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• v.10D no.5
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• pp.813-820
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• 2003

This paper solves Push-Push game with the model checker NuSMY which exhaustively explores all search space to determine whether a model satisfies a property. In case a model doesn't satisfy properties to be checked, NuSMV generates a counterexample which tells where this unsatisfaction occurs. However, the algorithm for generating counterexample in NuSMV traverses a search space twice so that it is inefficient for solving the game we consider here. To save the time to be required to complete the game, we revise the part of counterexample generation so that it traverses a search space once. As a result, we obtain 62% time improvement and 11% space improvement in solving the game with modified NuSMV.

• Journal of Korea Game Society
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• v.12 no.6
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• pp.25-32
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• 2012

Due to the development of the digital technology, the digital broadcasting is changing to a multi-entertainment platform that can operate data (broadcasting) services (such as games, weather information, and stock trading services) as well as traditional broadcasting contents. Most of the data services, however, failed to get satisfactory results because of the inconvenience in operating the services using a TV remote controller and the failure of gaining the viewer's interests in the competition with the broadcasting contents. The paper introduces a survey on the viewer's modality of using a data service and, based on the survey result, proposes a design guideline that makes a data service minimally interrupt a viewer watching a broadcasting content.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.568-571
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• 2004

본 논문의 목적은 벤처캐피탈(Venture Capitalist)의 투자전략을 게임이론을 통해 분석하고 이해하자는 것이다. 벤처캐피탈은 성장가능성은 높지만 불확실한 벤처기업에 투자하는 전문투자자이다. 벤처캐피탈은 이익을 극대화하기 위해서 성장가능성이 크고 위험관리가 가능한 기업에 투자를 하여야 한다. 하지만, 벤처캐피탈은 일반적으로 제한된 시간과 벤처기업의 속성 때문에 기업에 대한 정보가 부족한 상태에서 투자결정을 내려야 하는 경우가 대부분이다. 투자가 이루어진 후 벤처캐피탈은 벤처기업의 운영 및 기업활동을 감시(Monitor)하고 자문활동(Consulting Activity)을 수행하면서 차츰 기업에 대한 정보를 습득하게 되고 기업의 가치를 판단할 수 있게 된다. 본 논문은 앞에서 기술한 바와 같은 정보 불확실성 상태에서 창업자의 효용(utility)와 벤처캐피탈의 가치평가(value evaluation)를 바탕으로 벤처캐피탈의 투자전략을 게임이론을 통해 분석하였다. 본 논문은 벤처캐피탈이 전환사채형태의 투자를 하는 논거를 밝혀내었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.113-116
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• 2013

최근 방송, 의료, 우주산업, 게임, UCC, 핸드폰 등 여러 사업 분야에 걸쳐 실제에 근접한 영상을 요구하고 있고 이것은 3D와 Ultra High Definition (UHD) 영상의 출현으로 현실화 되고 있다. UHD 급에 걸맞는 압축률을 위해 Joint Collaborative Team on Video Coding (JCT-VC) 에서는 MPEG-4 Part 10 AVC/H.264를 뒤이을 차세대 코덱으로 High Efficiency Video Coding (HEVC) 를 개발을 시작했다. HEVC는 기존 MPEG-4 Part 10 AVC/H.264코덱과 비교해 40%이상의 압축률을 나타내지만 복잡도 역시 상승했다. 특히 복호화기에서 복잡도는 중요한 요소이며, 역 코사인변환 (Inverse Discrete Cosine Transform, IDCT) 은 전체 복호화시간의 8% ~ 16%를 차지하는 알고리즘이다. 본 논문에서는 IDCT 의 수행시간을 줄이기 위해 병렬프로그래밍 중의 하나인 SIMD명령어를 사용하여 효율적으로 병렬화 프로그래밍을 하는 기법들을 제안한다. 본 제안 기법은 IDCT 수행시간을 평균 59% 단축하는 결과를 보였다.

• The KIPS Transactions:PartB
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• v.10B no.2
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• pp.213-218
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• 2003

In this paper, we implement a crossword game, which operate by speech. The CAA (Cross Array Algorithm) produces the crossword array randomly and automatically using an domain-dictionary. For producing the crossword array, we construct seven domain-dictionaries. The crossword game is operated by a mouse and a keyboard and is also operated by speech. For the user interface by speech, we use a speech recognizer and a speech synthesizer and this provide more comfortable interface to the user. The efficiency evaluation of CAA is performed by estimating the processing times of producing the crossword array and the generation ratio of the crossword array. As the results of the CAA's efficiency evaluation, the processing times is about 10ms and the generation ratio of the crossword array is about 50%. Also, the recognition rates were 95.5%, 97.6% and 96.2% for the window sizes of "$7{\times}7$", "$9{\times}9$," and "$11{\times}11$" respectively.}11$" respectively.vely.

• Journal of Korea Game Society
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• v.13 no.2
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• pp.99-110
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• 2013

As volume rendering has been applied for computer game, the visualization of volume data with surface data in one scene has been required. Though a hybrid rendering of volume and surface data have been developed using the GPGPU functionality, computer games which run on low-level hardware are difficult to perform the hybrid rendering. In this paper, we propose a new hybrid rendering based on DirectX 9.0 and general hardware. We generate the layered depth images from surface data using a new method to reduce the depth complexity and generation time. Then, we perform the hybrid rendering using the layered depth images. In the rendering process, we suggest a new method to transform the coordinate system from a surface coordinate to a volume coorinate and propose an accelerated rendering technique. As the result, we can perform volume-surface hybrid rendering in an efficient way.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.37-43
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• 2013

Purpose: The present study was conducted to investigate whether the directions of eye movement in playing computer games for certain period affected the change of near point of convergence (NPC) and fusional reserve (FR) or not. Methods: Total 40 subjects in 20s who have the visual acuity of 1.0 or higher without any ocular disease and accommodative dysfunction were asked to successively play computer games. After the subjects were moving eyes in horizontal and vertical directions for 40 and 90 minutes, their horizontal fusional reserves, vertical fusional vergence and near point of convergence were measured. Results: The near point of convergence showed a tendency to be receded after computer gaming in the horizontal and vertical directions, and both of horizontal and vertical fusional reserves were significantly reduced. The range of declined fusional reserves and receded near point of convergence after computer gaming for 90 minutes was smaller than those after computer gaming for 40 minutes. The change of binocular vision was affected by the horizontal eye movement rather than the vertical movement when analyzed by the direction of eye movement. Conclusions: This study revealed that the change in FR and NPC was different along with dominant direction of eye movement during visual display terminal (VDT) tasks. Therefore, the adjustment of VDT working time is required to prevent the dysfunction of binocular vision according to the dominant direction of eye movement during VDT task.