• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.04a
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• pp.7-12
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• 1992

The variable node plate bending element, ie, the element with one or two additional mid-side nodes is used in the analysis of mat foundation to generate the nearly ideal grid model in which more nodes are defined near the column location. The plate bending element used in this study is the one based on Mindlin/Reissner plate theory with substitute shear strain field and the nodal stresses of that element are obtained by the local smoothing technique. The interaction of the soil material with the mat foundation is modeled with Winkler springs connected to the nodal points in the mat model. The vertical stiffness of the soil material are represented in terms of a modulus of subgrade reaction and are computed in the same way as to the computation of consistent nodal force of uniform surface loading. Several mesh schemes were proposed and tested to find the most suitable scheme for mat foundation analysis.

• Journal of architectural history
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• v.11 no.4 s.32
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• pp.45-69
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• 2002

This study aims to find out the genetic characteristics of gridded subdivision area which has its origin from ancient local administrative city-Sangju, Jeonju, Namwon, Kwangju, Chungju. The spatial structure, based on the inter-relationship among gridded subdivision area, city wall, and topographic condition, and the morphological characteristics of gridded subdivision area are analyzed. The points of analysis on morphological characteristics of gridded subdivision area consist of the size of unit block, the organization system of unit block, the orientation of subdivision line. As a result of the analysis, three main characteristics are found. Firstly there can be found no same land subdivision rule among study areas. Secondly, the morphological features of study area were the products of cumulative process of different subdivision areas which were developed in different periods. Thirdly, the original regular gridded land subdivision seems to have been carried out in the object of a farm-land cultivation around 7th century. And there was a change of land-use from farm land to urban land-use during the later 7th century and 8th century.

• Journal of Ocean Engineering and Technology
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• v.16 no.6
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• pp.37-43
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• 2002

The calculation of earthwork plays a major role in the plan or design phase of many civil engineering projects, such as seashore reclamation; and thus, it has become very important to improve upon its accuracy. There have been common drawbacks to earlier methods of ground profiling, such as dialing with sharp corners or the grid points of any tow straight lines. In this paper, we prepose an algorithm for finding a terrain surface using the natural boundary conditions and the both direction spline method, which interpolates the given three-dimensional data by using spline. As a result of this study, the algorithm of the proposed two methods to estimate pit excavation volume should provide a better accuracy than Spot height, Chambers, Chen, or Lin method. Also, the mathematical model mentioned offers maximum accuracy in estimating the volume of a pit excavation.

• Journal of Aquaculture
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• v.14 no.1
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• pp.43-50
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• 2001

To study the effect of paddle wheel on water circulation, velocity components were measured in shrimp ponds both along the longitudinal direction from a single paddle wheel and at 25 grid points of two ponds, which have mean water depth of 1.2m and aspect ratio (length/width) 1.05 and 0.68, respectively. An analysis of factors related to water quality and circulation showed that I) a single paddle wheel has an effective distance of 33m for de-stratification, 16m for particulate suspension and 25m for removal of organic material, dispersion of DO and prevention of bed sediment disturbance and ii) with doubling the number of paddle wheels at the pond corners, the flow speed increased by 13% over the ponds, while it reduced by 8.5% around the pond centres. Contrary to expectation, increasing the number of paddle wheel did not generate strong circulation around the pond centre and improve water quality.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.12
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• pp.1-12
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• 1996

A new local path planning algorithm using DPH (distance profile histogram) is suggested in this paper. The proposed method makes a grid type world map using distance values from multiple ultrasonic sensors and genrates local points through which the mobile robot can avoid obstcles safely. The DPH (distance profile historgram) represents geometrical arrangement of obstacles around the robot in the local polar coordinate system which is assumed to be atached to the robot. To control robot's navigation, a three-layered control structure is adopted. The proposed local path planning algorithm is placed on the top level. And a point-to-point translation controller takes the middle level. The bottom level consists of a velcoity servo and sonar driver modules which take charge of driving physical hardwares. The validity of the propsoed method is demonstated through several experiments.

• 한국전산유체공학회:학술대회논문집
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• 2007.10a
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• pp.232-235
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• 2007

A comprehensive numerical study was carried out to identify the on-set condition of the cell structures of oblique detonation waves (ODWs). Mach 7 incoming flow was considered with all other flow variables were fixed except the flow turning angles varying from 35 to 38. For a given flow conditions theoretical maximum turning angle is $38.2^{\circ}$ where the oblique detonation wave may be stabilized. The effects of grid resolution were tested using grids from $255{\times}100$ to $4,005{\times}1,600$. The numerical smoked foil records exhibits the detonation cell structures with dual triple points running opposite directions for the 36 to 38 turning angles. As the turning angle get closer to the maximum angle the cell structures gets finer and the oscillatory behavior of the primary triple point was observed. The thermal occlusion behind the oblique detonation wave was observed for the $38^{\circ}$ turning angle.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.389-392
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• 2000

Gouge-free tool-path generation is an important issue in mold & die machining and researches on cutter interference avoidance can be found in many articles. One of the various methods is construction of tool-offlet surface or cutter-location (CL) surface on which the cutter-center point (CL-point) locates. Provided that the CL surface is represented in a suitable form, cutter-interference avoidance can be performed without the burden of computing CL data for every cutter-contact (CC) point. In the paper, various methods of constructing a CL surface in the z-map form are presented, where z-map is a special form of discrete nonparametric representation in which the height values at grid points on the xy-plane are stored as a 2D array z［i,j］.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.87-90
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• 2004

A numerical analysis was made for the unsteady flow fields of rotor system of a Tilt-Rotor aircraft in cruise mode. The Reynolds-averaged thin-layer Navier-Stokes equations were discretized by Roe's upwind differencing scheme and integrated in time by the LU-SGS algorithm. The computational domain of the rotor system was constructed by six multi-block Chimera grids. Simulated unsteady flow fields of rotating blades were studied in several different view points.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.41-46
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• 2006

When new weapons are introduced, the target points estimation is one of the important objectives in the flight test as well as the safe separation. The prediction methods help to design the flight test schedule. However, the incremental aerodynamic coefficients in the aircraft flow field so-called BSE are difficult to predict. Generally, the semiempirical methods such as the grid methods, IFM and Flow TGP using database are used for estimation of BSE. However, these methods are quasi-steady methods using static aerodynamic loads. Nowadays the time-accurate CFD method is often used to predict the store separation event. In the current process, the incremental aerodynamic coefficients in BSE regime are calculated directly, and the elimination of delta coefficients is checked simultaneously. This stage can be used for the initial condition of Flow TGP with freestream database. Two dimensional supersonic and subsonic store separation problems have been simulated and incremental coefficients are calculated. The results show the time when the store gets out of BSE region.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.5
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• pp.453-462
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• 2009

The differential quadrature method(DQM) is applied to the free in-plane vibration analysis of circular curved beams with varying cross-section neglecting transverse shearing deformation. Natural frequencies are calculated for the beams with various opening angles and end conditions. Results obtained by the DQM are compared with available results by other methods in the literature. It is found that the DQM gives good accuracy even with a small number of grid points. In addition, the corrected results are given for the beams not previously presented for this problem.