• Journal of the Korea Society for Simulation
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• v.26 no.3
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• pp.23-34
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• 2017

This paper is to study the simulation model of depot maintenance system that analyzes logistics supportability such as component availability and cost of target equipment. A depot maintenance system could repair or maintain multiple components simultaneously. The key performance indicators of this system are component availability, repair cycle time, and maintenance cost. The simulation model is based on the engine maintenance process of army aviation depot. This study combines the NOLH(Nearly Orthogonal Latin Hypercube) experimental design method, to composes 33 scenarios, with a multiple regression analysis to find out major factors that influence on key performance indicators. This study is significant in providing a cost-effectiveness analysis on depot maintenance system that is capable of maintaining multiple components at the same time.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.383-387
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• 2006

자기유사(self-similar)과정은 인터넷 트래픽을 보다 정확하게 분석하는데 꼭 필요한 확률과정이다. 본 연구는 계산이 간편하고 다양한 시간범위의 종속성을 반영할 수 있는 M/G/${\infty}$에 모형을 기반으로 하여 자기유사과정을 생성하는 방법을 채택하고 G를 파레토 분포로 표준화하여 적용 가능성을 다양하게 실험한다. 시뮬레이션에서 이산화를 매 단위시점으로 설정하지 않고 대기열에서의 도착, 이탈시점으로 설정하여 시뮬레이션의 속도를 높이고 보다 정확한 성능측정이 이루어지도록 시도한다.

• Proceedings of the Korea Society for Simulation Conference
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• 2000.11a
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• pp.6-10
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• 2000

In regression model we estimate the unknown parameters using various methods. There are the least squares method which is the most general, the least absolute deviation, the regression quantile and the asymmetric least squares method. In this paper, we will compare each others with two case: to begin with the theoretical comparison in the asymptotic sense, and then the practical comparison using Monte Carlo simulation for a small sample size.

• The Journal of the Korea Contents Association
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• v.21 no.11
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• pp.77-86
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• 2021

A method of constructing a war simulation based on Bayesian Inference was proposed as a method of constructing heterogeneous historical war data obtained with a time difference into a single model. A method of applying a linear regression model can be considered as a method of predicting future battles by analyzing historical war results. However it is not appropriate for two heterogeneous types of historical data that reflect changes in the battlefield environment due to different times to be suitable as a single linear regression model and violation of the model's assumptions. To resolve these problems a Bayesian inference method was proposed to obtain a post-distribution by assuming the data from the previous era as a non-informative prior distribution and to infer the final posterior distribution by using it as a prior distribution to analyze the data obtained from the next era. Another advantage of the Bayesian inference method is that the results sampled by the Markov Chain Monte Carlo method can be used to infer posterior distribution or posterior predictive distribution reflecting uncertainty. In this way, it has the advantage of not only being able to utilize a variety of information rather than analyzing it with a classical linear regression model, but also continuing to update the model by reflecting additional data obtained in the future.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.50.3-50.3
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• 2015

고립된 은하쌍 내의 두 은하의 스핀 각운동량의 각도 차이의 분포를 구하고 이를 통계적으로 분석한 결과를 관측 데이터와 수치 시뮬레이션 데이터 간에 비교함으로써 ${\Lambda}CDM$ 모형이 아닌 다른 우주 모형의 주요 변수를 규제할 수 있다. 이 연구에서는 결합된 암흑 에너지 (coupled dark energy, cDE) 모형의 주요 변수인 결합 함수를 규제하기 위해 서로 다른 조건의 cDE 모형과 ${\Lambda}CDM$ 모형에 따라서 생성한 수치 데이터의 스핀 정렬을 Argudo-Fernandez et al. (2015) 에서 인용한 관측 데이터의 스핀 정렬과 비교하였고, ${\Lambda}CDM$ 모형과 대부분의 cDE 모형의 수치 데이터는 관측 데이터와 부합하나 일부 cDE 모형은 부합하지 않아서 제외될 가능성이 높음을 확인하였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.203-210
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• 2003

격자망식 전선배치에 의한 전기비저항 측정기법을 이용한 침출수 누출감지시스템을 개발하여 그 적용성을 평가하기 위하여 현장모형시험을 수행하였다. 현장모형시험을 수행한 결과 침출수 누출지점에서 전기비저항이 크게 감소하여 누출지점을 정확하게 감지할 수 있었다. 격자망식 전선배치에 의한 전기회로적인 효과로 인하여 전기비저항이 감소된 지점과 동일 전선상에 연결된 다른 센서에서의 측정값도 다소 감소하는 경향을 나타내었다. 이를 보정하기 위하여 P-SPICE를 이용하여 전기회로 시뮬레이션을 수행하여 전기회로 효과를 정량적으로 평가하였다 P-SPICE 시뮬레이션의 결과를 토대로 보정계수를 도출하여 현장모형시험결과를 보정하였으며, 보정된 겉과에 의하면 전기회로적 특성에 의한 영향을 효과적으로 제거되어 누출지점에서의 전기비저항 감소가 명확하게 나타났다.

• Proceedings of the Korean System Dynamics Society
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• 2002.11a
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• pp.59-100
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• 2002

This study examines the effect that the prepaid trust has in saving the troubled business through the development of a formal system dynamics model. Building on existing case studies of corporate turnaround. we develop a mathematical model on the relationship between the prepaid trust and turnaround. With it. we build a system dynamics model in order to show how the prepaid trust can shift an organizational system from fragile condition of a firm to resilient condition of a firm. The model, which is oriented by attribution theory and problem-sharing by crisis communication. is developed in the aspect of the process from 'clouds' to 'evaporating clouds' This study offers a new characterization of the conditions under which organizations may be recovered the performance by prepaid trust through simulations of the model, and provides both theoretical insights into the corporate turnaround and practical suggestions for those charged with corporate turnaround.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.3
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• pp.140-154
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• 1997

On November 15, 1994 at 03:17 local time, an earthquake of surface magnitude (M$_{s}$) 7.0 occurred on the northern coast of the Mindoro in Philippine. A major tsunami was generated by this earthquake, extremely large tsunami waves engulfed the Mindoro and the Verde islands. This tsunami caused tremendous casualities and damage. The tsunami propagated to the Luzon island and felt at the Batangas after 10 minutes. The present paper intends to understand the propagation and inundation this tsunami with the aid of numerical computation model and computer graphic aided video animation.n.

• Journal of Cadastre & Land InformatiX
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• v.53 no.2
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• pp.53-66
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• 2023

Recently, there has been a significant interest in the development of autonomous driving simulation environment based on digital twin. In the development of such digital twin-based simulation environment, many researches has been conducted not only performance and functionality validation of autonomous driving, but also generation of virtual training data for deep learning. However, such digital twin-based autonomous driving simulation system has the problem of requiring a significant amount of time and cost for the system development and the data construction. Therefore, in this research, we aim to propose a method for rapidly designing and implementing a digital twin-based autonomous driving simulation system, using only the existing 3D models and high-definition map. Specifically, we propose a method for integrating 3D model of FBX and NGII HD Map for the Busan EDC area into CARLA, and a method for adding and modifying CARLA functions. The results of this research show that it is possible to rapidly design and implement the simulation system at a low cost by using the existing 3D models and NGII HD map. Also, the results show that our system can support various functions such as simulation scenario configuration, user-defined driving, and real-time simulation of traffic light states. We expect that usability of the system will be significantly improved when it is applied to broader geographical area in the future.

• Journal of the Korea Society for Simulation
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• v.23 no.3
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• pp.1-9
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• 2014

Traditional workflow time analyses have been performed treating an activity as an independent M/M/1queueing system. Using the general forms of performance measures in the M/M/1 system, various aspects of analyses can be performed. Especially, on the time analysis of an AND structure in a workflow system, the mean system sojourn time can be formalized by applying the performance measures of M/M/1 system. In the real workflow system, the AND structure cannot be described correctly under the assumption of independent M/M/1 systems. To overcome this limitation, this research makes the assumption that the all activities for a task starts simultaneously. In this situation, the theoretical solution can be derived using the performance measures of the M/G/1 system. In addition, the simulation modeling method will be proposed to analyze the AND structure of a real workflow system. Finally, some numerical results from the theoretical solutions and simulation models will be provided for verification. The main performance measures used in this research are mean queueing time and mean sojourn time.