• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.2
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• pp.163-169
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• 1995

A two-dimensional numerical tidal model is formulated to reproduce tides in the Southwestern Sea of Korea. Tidal charts and ellipses of eight major tidal constituents (M$_2$, S$_2$, K$_1$, O$_1$, N$_2$, K$_2$, P$_1$, Q$_1$) are presented. Model results show that the semi-diurnal tides are dominant in this area. Maximum transport by tides in the Cheju Strait is about 4.2${\times}$10$\^$6/ ㎥/sec which is greater by eight times than that by residual current.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.8 no.2
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• pp.35-43
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• 1990

In this paper a two dimensional network adjustment theory is developed to analyze the plane trilateration network of single triangle network, of quadrilateral network, of polygon trilateration network and of combined network. The characteristics of error were analysed by developing an error propagation equation for each form of plane trilateration network. In case of combined network, the result of error analysis was represented by error ellipses and gross error detection was carried out by data snooping method.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.2
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• pp.151-171
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• 1993

The review presented herein covers most of previous works on tidal models of the East China Sea and the Yellow Sea performed over past two decades including some earlier efforts. General description of tides in the region is given based on both numerically derived tidal charts, current ellipses and intelligently drawn empirical tidal charts. Some aspects of bottom tidal dissipation, tidal mixing, tidal sedimentation and tidal circulation utilizing the numerical tidal models are presented, and further discussions on inherent problems and development of the models are also given.

• Bulletin of the Society of Naval Architects of Korea
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• v.5 no.2
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• pp.45-50
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• 1968

The added mass and the added moment of inertia of a hard chine hull for heave and pitch were calculated by strip method. For the $k_2$ coefficients, Hwang's values for the straight-framed sections were used and for $k_2$ coefficients Porter's values for ellipses were used in the calculation. Comparisons on added mass and added moment of inertia of hard chine hull with those of ordinary hull form were briefly discussed. The results of the calculation for hard Chine hull give greater valves than ordinary ships at zero Froude Number. Beam draft ratio seems to be much influenced on the added mass and added moment of inertia.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.6 no.4
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• pp.421-438
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• 1994

Vertical distribution of tidal currents in the Korea Strait is computed by a tree-dimensional tidal model. The results are presented in the from of tidal charts (coamplitude and cophase chart) and (tidal ellipses charts for eight tidal constituents (M$_2$, S$_2$, $N_2$, $K_2$, $K_1$, $O_1$, P$_1$, Q$_1$) and of harmonic constants for predictions of tides and tidal currents during specified duration in the region. The computed tides were in general agreement with coastal observations and observation-based tidal charts of Odamaki (1989). Comparison between model computation and current observation by RIAM were also presented.

• Journal for History of Mathematics
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• v.27 no.6
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• pp.395-402
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• 2014

When the circle inscribed in a square is projected to a picture plane, one sees, in general, an ellipse in a convex quadrilateral. This ellipse is poorly described in the works of Alberti and Durer. There are one parameter family of ellipses inscribed in a convex quadrilateral. Among them only one ellipse is the perspective image of the circle inscribed in the square. We call this ellipse "the projected ellipse." One can easily find the four tangential points of the projected ellipse and the quadrilateral. Then we show how to find the center of the projected ellipse. Finally, we describe a pair of conjugate vectors for the projected ellipse, which finishes the construction of the desired ellipse. Using this algorithm, one can draw the perspective image of the squared-circle tiling.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.3
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• pp.168-177
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• 1992

Some features of tidal energy horizontal flux in the ocean are considered. using the concept of “energy flux ellipses” which is a hodograph of momentary fluxes over a tidal semi-period. A number of characteristics of this ellipse are considered as well as some peculiarities of energy flux field in different types of tidal waves and their combinations (plane, Kelvin, Sverdrup, Poincare, amphidromic system). For forced tidal waves in equatorial channels some results are obtained explaining the dependence of energy flux direction on the channel dimensions.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.1
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• pp.29-37
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• 1991

A two-dimensional numerical model. using finite element method. was applied to calculation of the tides and tidal currents of four major tidal constituents($M_2, ;S_2, ;K_1, ;O_1$) in the southern part of the East Sea. The model results were compared with the observed data and with the existing tidal charts. and the computed results showed good agreement with the observation. As a result, the detailed tidal charts for four major tidal constituents and the tidal current ellipses of the M$_2$and $K_1$tides were produced respectively. The results indicate that the amphidromic point of diurnal tide locates near Korean coastal lines closer than that of the chart drawn by Nishida(1980).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.909-912
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• 2012

An automated cell tracking system is automatically to analyze and track changes of cell behaviors in time-lapse cell images acquired from microscope in the cell culture. In this paper, we proposed and developed an ellipse fitting based algorithm for separating very small size overlapping cells in a cell image consisted of thousands or ten thousands cells. We were extracted contours of clusters and divided them into line segments and then produced their fitted ellipses for each line segment. By experimentations, our algorithm was separated clusters with average 91% precision for two overlapping cells and average 84% precision for three overlapping cells respectively.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.772-777
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• 2003

A vision-based tool position estimation system for the inspection and maintenance manipulator working inside the steam generator bowl of nuclear power plants can help human operators ensure that the inspection probe or plug are inserted to the targeted tube. Some previous research proposed a simplified tube position verification system that counts the tubes passed through during the motion and displays only the position of the tool. In this paper, by using a general camera calibration approach, tool orientation is also estimated. In order to reduce the computation time and avoid the parameter bias problem in an ellipse fitting, a small number of edge points are collected around the large section of the ellipse boundary. Experiment results show that the camera calibration parameters, detected ellipses, and estimated tool position are appropriate.