• 대한수학회지
• /
• 제49권5호
• /
• pp.893-905
• /
• 2012

Kirsi Majava and Xue-Cheng Tai [12] proposed a modified level set method for solving a free boundary problem associated with unilateral obstacle problems. The proximal bundle method and gradient method were applied to solve the nonsmooth minimization problems and the regularized problem, respectively. In this paper, we extend this approach to solve the bilateral obstacle problems and employ Rung-Kutta method to solve the initial value problem derived from the regularized problem. Numerical experiments are presented to verify the efficiency of the methods.

• 한국GIS학회:학술대회논문집
• /
• 한국GIS학회 1999년도 추계학술대회 발표요약문
• /
• pp.1-4
• /
• 1999

This study was performed to develop an information processing system for the sound conservation of soil and groundwater resources. The system contains the geographic information system, and the numerical model of groundwater flow and contamination. Numerical models (MODFLOW,MOC3D) and GIS (ArcView) were integrated for the construction of an integrated management system of subsurface environment. The developed system was applied to the management of three mineral water companies located in clean mountain area. The impact of pumping over the overall catchment basin was modeled using the developed system for the decision of future management criteria.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.1513-1517
• /
• 2010

Recently, the important of Progress Management is being emphasized because construction have become more complex and increasingly specialized. The existing progress control method needs to be changed because only numerical information is being provided and is very difficult to understand all poor progress. To resolve these problem, this study suggests a simulation method for progress management by using 4D CAD System because 4D CAD system has effective functions to convert numerical information to visualized information. The suggested simulation method not only are reviewed an application of railway construction but enables managers to understand problems in managing this system for verifying the suggested simulation method.

• 산업기술연구
• /
• 제19권
• /
• pp.287-291
• /
• 1999

This study was performed to develop an information processing system for the sound conservation of soil and groundwater resources. The system contains the geographic spatial information system(GSIS), and the numerical model of groundwater flow and contamination. Numerical models (MODFLOW, MOC3D, MT3D, PMPATH, PEST, UCODE) and GSIS(ArcView) were integrated for the construction of an integrated management system of subsurface environment. The developed system was applied to the management of three mineral water companies located in clean mountain area. The impact of pumping over the overall catchment basin was modeled using the developed system for the decision of future management criteria.

• 한국전산유체공학회지
• /
• 제19권2호
• /
• pp.8-16
• /
• 2014

Two-dimensional prediction capability of several analysis codes, such as XFOIL, MSES, and KFLOW, is compared and analyzed based on computational results of airfoil flows. To this end the transition transport equations are coupled with the Navier-Stokes equations for the prediction of the natural transition and the separation-induced transition. Experimental data of aerodynamic coefficients are used for comparison with numerical results for the transitional flows. Numerical predictions using the transition transport model show a good agreement with experimental data. Discrepancies have been found in the prediction of the pressure drag are mainly caused by the difference in the far-field circulation correction methods.

• Journal of Mechanical Science and Technology
• /
• 제15권3호
• /
• pp.281-290
• /
• 2001

Particle contamination has been an ongoing problem affecting the reliability of the magnetic hard disk drives. Especially the recent use of MR head requires much tighter control of particle contamination due to thermal asperity (TA) phenomenon. In this study, the effects of slider air bearing surface design of TA reduction capability were investigated by manufacturing two types of sliders. Numerical methods were used to simulate the motion of particles in the head/media interface. Experiments were conducted to verify the results predicted by the numerical simulation. Drives were built and exposed to particle contamination using a particle injection chamber, which turned out to be a very simple and reliable particle generation method over conventional aerosol technique. Then the number of TA generated in the drives was recorded and compared. Also the contacts between slider and particles were investigated by acoustic emission study. It was found that a new ABS design, which has aerodynamic U-shaped rail and central flow passage, was beneficial in reducing the particle contamination on the slider.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제14권10호
• /
• pp.4007-4024
• /
• 2020

It is tremendously important to construct decision trees to use as a tool for knowledge representation from a given decision table. However, the usual algorithms may split the decision table based on each value, which is not efficient for numerical attributes. The methodology of this paper is to split the given decision table into binary groups as like the CART algorithm, that uses binary split to work for both categorical and numerical attributes. The difference is that it uses split for each attribute established by the directed acyclic graph in a dynamic programming fashion whereas, the CART uses binary split among all considered attributes in a greedy fashion. The aim of this paper is to study the effect of binary splits in comparison with each value splits when building the decision trees. Such effect can be studied by comparing the number of nodes, local and global misclassification rate among the constructed decision trees based on three proposed algorithms.

• International Journal of Control, Automation, and Systems
• /
• 제6권4호
• /
• pp.515-525
• /
• 2008

In this paper, the problem of delay-dependent stabilization for singular systems with multiple internal and external incommensurate constant point delays is investigated. The condition when a singular system subject to point delays is regular independent of time delays is given and it can be easily test with numerical or algebraic methods. Based on Lyapunov-Krasovskii functional approach and the descriptor integral-inequality lemma, a sufficient condition for delay-dependent stability is obtained. The main idea is to design multiple memoryless state feedback control laws such that the resulting closed-loop system is regular independent of time delays, impulse free, and asymptotically stable via solving a strict linear matrix inequality (LMI) problem. An explicit expression for the desired memoryless state feedback control laws is also given. Finally, a numerical example illustrates the effectiveness and the availability for the proposed method.

• ETRI Journal
• /
• 제36권6호
• /
• pp.968-978
• /
• 2014

Autonomous vehicle technology based on information technology and software will lead the automotive industry in the near future. Vehicle localization technology is a core expertise geared toward developing autonomous vehicles and will provide location information for control and decision. This paper proposes an effective vision-based localization technology to be applied to autonomous vehicles. In particular, the proposed technology makes use of numerical maps that are widely used in the field of geographic information systems and that have already been built in advance. Optimum vehicle ego-motion estimation and road marking feature extraction techniques are adopted and then combined by an extended Kalman filter and particle filter to make up the localization technology. The implementation results of this paper show remarkable results; namely, an 18 ms mean processing time and 10 cm location error. In addition, autonomous driving and parking are successfully completed with an unmanned vehicle within a $300m{\times}500m$ space.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2005년도 춘계종합학술대회
• /
• pp.685-688
• /
• 2005

대표적인 이중곡면 산란체인 타원체를 표준 구조물로 설정하여 역방향(backscattering)에서의 고주파 전자파 산란 해석을 위한 creeping wave을 구하는 방법에 대해 알아보았다. 타원체는 비행기나 미사일 형태의 몸체를 모델링하는 기본 구조물이다. 시뮬레이션으로 타원체 표면에서의 geodesic path의 결과를 제시하였다.