• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.78-84
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• 2017

Compared to other types of power, hydraulic energy is the most commonly used for heavy vehicles and ships because it has fewer location and space constraints, and its controllability can be maintained even under adverse conditions. Operators have controlled a main control valve of ship winches by pushing or pulling the lever, which is directly connected to the spool. However, because of the spatial arrangement, the importance of remote control valves has emerged. In this paper, experiments of the hysteresis characteristics were performed by analyzing the remote-control valve using a valve tester and RA2300. The validity was verified by comparing with the analytical model using SimulationX as the hydraulic analysis program. This study examined the effects of the spool's notch (Non, End-mill, and Spherical) and the effects of stiffness and pre-load of the spool spring on Spool stroke, open area, and hysteresis characteristics. It is considered possible to reduce the cost and the, trial and error process in designing remote-control valves in the future.

• The Korean Journal of Applied Statistics
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• v.18 no.3
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• pp.689-699
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• 2005

We usually use $S^2=\frac{{\Sigma}^n_{i=1}(X_i-\={X})^2}{n-1}$ as sample variance. Korean high school text-books use $S^2_n=\frac{{\Sigma}^n_{i=1}(X_i-\={X})^2}{n}$as sample variance. We can compare the above two definitions of sample variance through their theoretical relationship and simulation.

• The Transactions of the Korea Information Processing Society
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• v.1 no.1
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• pp.92-98
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• 1994

The hypercube-like interconncetion network,X-hypercubes,has the same number of nodes and edges as conventional hypercubes.By slightly changing the interconneton way between nodes,however,X-hypercubes reduces the diameter by almost half.Thus the communication delay in X-hypercubes can be expected to be much lower than that in hypercubes. This paper gives a new definition of X-hypercubes establishing clear-cut condition of connection between two nodes.As appliction examples of the new definition,this paper presents simple embeddings of hypercubes in X-hypercubes and vice versa.This means that any programs written for hypercubes can be transported onto X-hypercubes and vice versa with minimal overhead.This paper also present bitonic merge sort for X-hypercubes by simulation that for hypercubes.

• Journal of the Korea Society for Simulation
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• v.27 no.2
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• pp.11-24
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• 2018

The purpose of the present study is to develop an analysis model to analyze the design parameter sensitivity of a high-power drifter suitable for implementation in Korean hydraulic drills. This study aims to establish a basis for the optimization of the impact performance and stability of a high-power drifter by investigating the effects of each design parameter on the impact performance via design parameter sensitivity analysis. To begin, an analysis model of drifter dynamics is developed, and the reliability of the analysis model is verified by comparing the analysis results to the experimental results. The drifter is then redesigned for compatibility with Korean hydraulic drills. Finally, design parameter sensitivity analysis of the redesigned drifter is conducted to determine the effects of the design parameters on the impact performance, and to extract the high-sensitivity parameters. SimulationX, which is multi-physics analysis software, is used to develop the analysis model, and EasyDesign is employed for design parameter sensitivity analysis.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.2
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• pp.244-250
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• 2015

We propose a simulation technique to estimate the reduction effect of the pressure/flow pulsation by analysis of the pulsation variables and notch shape of the valve plate of a swash-plate-type variable piston pump. First, using SimulationX$^{(R)}$, we perform a theoretical kinematic analysis according to the variable swash-plate angle and rotational velocity in order to design a single-piston pump. In designing the notch shape of the valve plate of the swash-plate-type variable piston pump as one of the pulsation variables, we investigate the effect of the pulsation by comparing two notch types (circular type and V type). Then, we extend our analysis to a nine-piston pump model. This paper not only confirms the effect of the pressure/flow pulsation according to pulsation variables but can also be applied to the development of a SimulationX$^{(R)}$-based simulation technique for notch-shape optimization for a swash-plate-type variable piston pump.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.221-225
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• 2001

Recently, high accuracy and high precision are required in various industrial fields that are composed of semiconductor manufacturing apparatus and ultra precision positioning apparatus and information system and so on. The positioning technology is a very important one among them. This technology has been rapidly developed, its field needs for positioning accuracy to high as submicron. It is expected that accuracy with 10 nm in precision working and accuracy with 1 nm in ultra precision working are reached at the beginning of 2000s. Recently, to accomplish this positioning technology, many researches are concerned about it and make efforts it. This paper contain design technology of ultra precision 2-axis(X-Y Delta) stage for materialize to positioning accuracy with submicron, where, Delta stage is design as optimum against load and disturbance. And computer simulation is performed for stability and dynamic characteristic of Delta stage.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.11a
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• pp.73-77
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• 2002

이 논문은 빠른 ASIP(application specific instruction processor) 시뮬레이션을 위한 재적응성을 가진 컴파일드 시뮬레이션 기법에 대해 이야기 한다. 다양한 응용분야에서의 설계 요구사항을 충족시키는 ASIP의 빠른 개발을 위해서, 건전한 설계 방법론 및 고성능의 시뮬레이터가 필요하다. 본 논문에서는 HiX$R^2$라는 ADL(architecture description language)을 이용하여 인스트럭션 수준에서 컴파일드 시뮬레이터를 자동 생성하였다. 컴파일드 시뮬레이션은 시뮬레이션 수행 시 반복되는 인스트럭션 페칭 및 디코딩 부분을 시뮬레이션 런-타임 이전에 미리 수행함으로서 일반적으로 사용되는 인터프리티브 시뮬레이션에 비하여 큰 성능향상을 얻을 수 있다. HiX$R^2$에 기반 한 컴파일드 시뮬레이션은 ARM9 프로세서와 CalmRISC32 프로세서 예제들로 수행하였고, 결과로서 인터프리티브 방식에 비해 150배 이상의 성능향상이 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.523-526
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• 2002

This paper presents the simulation of Au / $Ba_{x}$S $r_{1-x}$ Ti $O_3$(BSTO) / Magnesium oxide (MgO) multi-layered and electrically tunable band-pass filters (BPFs) by using high frequency structure simulator (HFSS). This model is a two-pole microstrip edge coupled filter. The filter was designed fur a center frequency about 5.8 GHz. The tunabillity of the filter is achieved using the nonlinear dc electric-field dependence on the relative dielectric constant of BSTO frroelectric thin film. This work seems very promising for future wireless communication systems....

• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.202-209
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• 1999

한국전력공사 전력연구원 로봇 원격제어기술과 가상현실기술을 접목하는 과정의 일환으로 로봇작업을 3-D 그래픽으로 시뮬레이션하는 연구를 수행하였다. 본 논문에서는 로봇언어를 이용하여 이동경로를 생성하고 이동된 로봇의 위치와 자세정보를 그래픽변수와 연결하여 가시화하는 일련의 과정을 다룬다. 개발된 시뮬레이션 패키지는 실시간으로 로봇의 움직임을 관찰하는 목적 이외에 로봇작업경로의 생성과 로봇설계 등의 엔지니어링 목적으로도 활용할 수 있는 기능을 갖추고 있다. 이 시스템은 사용자의 편이성과 로봇의 신뢰성 및 가격적인 면 등을 고려하여 팬티엄-II급 산업용 PC와 Windows NT로 구성되어 있고, 그래픽 툴로는 Microsoft가 멀티미디어용으로 개발한 DirectX를 활용하였다. DirectX는 다양한 예제 프로그램을 포함하고 있는 Software Design Tool을 제공하므로 소프트웨어 개발시간을 단축시키는 장점을 가지고 있다.

• Journal of the Korean Data and Information Science Society
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• v.8 no.2
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• pp.143-152
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• 1997

In this paper, we obtain maximum likelihood estimators for $P(X_{1}\;<\;X_{2})$ in the Marshall and Olkin's bivariate exponential model with bivariate censored data. The asymptotic normality of the estimator is derived. Also we propose approximate testing for $P(X_{1}\;<\;X_{2})$ based on the M.L.E. We compare the test powers under vsrious conditions through Monte Carlo simulation.