• Water Engineering Research
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• 제3권1호
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• pp.23-30
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• 2002

A numerical model for the solution of two-dimensional dam break problems using fractional step method is developed on unstructured grid. The model is based on second-order Weighted Averaged Flux(WAF) scheme with HLLC approximate Riemann solver. To control the nonphysical oscillations associated with second-order accuracy, TVD scheme with SUPERBEE limiter is used. The developed model is verified by comparing the computational solutions with analytic solutions in idealized test cases. Very good agreements have been achieved in the verifications.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.443-445
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• 2005

In this paper, we propose an MVA mode cell structure with improved optical characteristics. Our MVA cell has an electrode with fine-slits. Optical characteristics of our proposed structure were compared with those without fine-slits. Moreover, we varied the interval as well as the widths of fine-slits in order to appreciate the effect of fine-slits. Optical characteristics of these cells were calculated with 3DFEM solver, TechWiz LCD. It was confirmed that the transmittance can be improved by more than 7% with fine-slits.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.439-442
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• 2005

In this paper, we propose a cell structure to improve transmittance and aperture ratio with FFS(Fringe Field Switching) mode. As an exemplary cell, we selected conventional FFS cell with dual domain. Optical transmittance and aperture ratio were calculated with 3DFEM numerical solver, TechWiz LCD. The simulation results revealed that transmission increases by more than 10% while aperture ratio increases by more than 4% when compared to conventional FFS mode.

• 대한조선학회논문집
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• 제42권3호
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• pp.249-258
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• 2005

Recently, the vibration reduction at a local structure such as compass deck has been continuously requested by ship owner and shipbuilder. Because crews are afflicted with vibration, severe vibration problems even bring about a damage of structure. This study conducted to get an optimized stiffener size of compass deck to reduce the vibration level and decrease the weight of structure in ship. NASTRAN external call type optimization software (OptShip) which makes use of NASTRAN as a solver is used as an optimization tool. The results indicate that the optimum design is promising for real applications.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.436-441
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• 2001

In this paper, stacker crane is modeled as rigid elements and discrete flexible beam connections by kinematics & dynamics solver package program instead of deriving the equations of motion which describes the total dynamics of the system. For the simulation of structural dynamics, ADAMS, a software for the simulation of multiple rigid body dynamics, is used. Some kinds of works are fulfilled to examine the dynamic characteristics of system. In order to verify the analysis method, the results of simulation and experiment are compared.

• Journal of the Korean Physical Society
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• 제73권9호
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• pp.1269-1278
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• 2018

Using the thawed Gaussian wave packets [E. J. Heller, J. Chem. Phys. 62, 1544 (1975)] and the adaptive reinitialization technique employing the frame operator [L. M. Andersson et al., J. Phys. A: Math. Gen. 35, 7787 (2002)], a trajectory-based Gaussian wave packet method is introduced that can be applied to scattering and time-dependent problems. This method does not require either the numerical multidimensional integrals for potential operators or the inversion of nearly-singular matrices representing the overlap of overcomplete Gaussian basis functions. We demonstrate a possibility that the method can be a promising candidate for the time-dependent $Schr{\ddot{o}}dinger$ equation solver by applying to tunneling, high-order harmonic generation, and above-threshold ionization problems in one-dimensional model systems. Although the efficiency of the method is confirmed in one-dimensional systems, it can be easily extended to higher dimensional systems.

• 로봇학회논문지
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• 제12권4호
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• pp.385-394
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• 2017

Side scanning sonar (SSS) provides valuable information for robot navigation. However using the side scanning sonar images in the navigation was not fully studied. In this paper, we use range data, and side scanning sonar images from UnderWater Simulator (UWSim) and propose measurement models in a feature based simultaneous localization and mapping (SLAM) framework. The range data is obtained by echosounder and sidescanning sonar images from side scan sonar module for UWSim. For the feature, we used the A-KAZE feature for the SSS image matching and adjusting the relative robot pose by SSS bundle adjustment (BA) with Ceres solver. We use BA for the loop closure constraint of pose-graph SLAM. We used the Incremental Smoothing and Mapping (iSAM) to optimize the graph. The optimized trajectory was compared against the dead reckoning (DR).

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.515-518
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• 2005

In this paper, we report on our theoretical study on the effect of surface anchoring. Molecular dynamics as well as optical characteristics of PVA cell are computer-simulated with 3D-FEM numerical solver, TechWiz $LCD^{(R)}$. Although simulation parameters are the same except for the consideration of surface anchoring, the simulation reveals that optical transmittance is improved by more than 8% for the weak anchoring case with comparison to the strong anchoring case. Moreover, capacitance between pixel and common electrode is 7% lower for the strong anchoring than that for the weak anchoring. This implies that there exists an appreciable difference between the strong anchoring case and the weak anchoring case. It is very important to take the effect of surface anchoring into account in order to figure out the optical characteristics of an LCD cell more accurately.

• 청정기술
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• 제18권3호
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• pp.320-324
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• 2012

본 연구에서는 리튬이온전지의 방전특성에 따른 열발생 속도를 계산하여 전지의 특성을 평가하였다. 이를 위하여 Butler-Volmer 식을 지배방정식으로 하여, 유사 2차원 모델링을 적용하고, 편미분 연산자인 FEMLAB을 이용하여 전산모사를 수행하였다. 전류밀도를 5 $A/m^2$에서 25 $A/m^2$까지 증가시켜 계산을 수행한 결과, 전류밀도가 증가함에 따라 전극표면에서 고체상 리튬의 소모량이 증가되는 것으로 나타났다. 이로 인한 확산제한의 발생시점이 단축되었으며, 동시에 리튬이온전지의 내부 전위가 컷오프 전위에 도달하는 시점에서 열발생 속도가 급격하게 증가되는 현상을 보여주었다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.281-285
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• 2008

Effective use of available energy sources is of general concern along with the issues of global warming and unstable oil price. As one of the effort to recover waste heat from industrial facilities effectively, researchers have interest in a technology called organic Rankine cycle(ORC), in which the working fluid is some organic liquid instead of water. Known to have poor efficiency already, this old technology is considered to give an innovative solution to utilizing low grade energy sources, by improving the efficiency. Nano fluidics, coatings and the use of additives are the examples of these efforts. In the present study, we present simulated performance of a horizontal tube type condenser geometry. N-hexanr and isopentane are compared to water vapor case under 1 atm and the inet cooling water temperature of $20^{\circ}C$. EES(Engineering Equations Solver) is used for the present work.