• Journal of Navigation and Port Research
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• v.32 no.8
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• pp.577-582
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• 2008

In order to ascertain the effect of ship's speeds, in maneuver under the condition of strong cross current in the breakwater channel of Busan port, this paper is to deal with the analyses of vessel proximity measures, vessel controllability measures, and ship handlers' subjective evaluation measures of simulated maneuvers, which were carried out by 76 ship handlers who conned Panamax bulk carrier of 60,000 DWT, The set and drift of current are southwesterly and 2 knots. The speeds of the model ship are 5 knots & 10 knots respectively. The followings are concluded. ${(1)}$ In the approaches of the breakwater of Busan port, ship handlers psychologically tend not to give the drift angle of more than $10^{\circ}$ bemuse ship's head points out of the entrance. ${(2)}$ Ship handlers' subjective evaluation, vessel proximity and controllability measures are relatively larger under the speed of 5 knots than under that of 10 knots. due to direct pressure of strong current. ${(3)}$ A single index of controllability measures was suggested, by removing their units.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2001.03a
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• pp.59-61
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• 2001

• Journal of the Korean Mathematical Society
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• v.30 no.2
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• pp.371-383
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• 1993

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.1
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• pp.43-50
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• 2010

The 200mesh screen was tensioned and fixed on a frame. When applied tension to 5N and 10N per unit area, a side length of opening of the screen was 163.223${\mu}m$ and 168.224${\mu}m$, respective. But side length not tensioned was 158.879${\mu}m$. We knew that a side length of opening of the screen rarely changes with tension applied to the screen. The appearances that a side length of opening of the screen expand little are due to a decreasing diameter of thread by means of tension. In a thickness measurement of screen, While the high density mesh screen that had a lot of knots that crossed a line of latitude and longitude per unit area appeared a higher numerical value, the low density mesh screen that had a few knots appeared a low numerical value.

• Journal of the Korean Mathematical Society
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• v.52 no.2
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• pp.389-402
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• 2015

A symmetric union is a diagram of a knot, obtained from diagrams of a knot in the 3-space and its mirror image, which are symmetric with respect to an axis in the 2-plane, by connecting them with 2-tangles with twists along the axis and 2-tangles with no twists. This paper presents an invariant of knots with symmetric union presentations, which is called the minimal twisting number, and the minimal twisting number of $10_{42}$ is shown to be two. This paper also presents a sufficient condition for non-amphicheirality of a knot with a certain symmetric union presentation.

• Journal of Institute of Convergence Technology
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• v.6 no.2
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• pp.9-13
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• 2016

Robot usually requires spline motion to move through multiple knots. In this paper, catmull-rom spline method is applied to the trajectory planning of industrial robot in task space. Centripetal catmull-rom is selected to avoid self-intersection and slow motion which can be occurred in uniform and chordal spline. The method to set two control points are proposed to satisfy velocity conditions of initial and final knots. To optimize robot motion, time scaling method is presented to minimize margin between real robot value and maximum value in velocity and acceleration. The simulation results show that the proposed methods are applied to trajectory planning and robot can follow the planned trajectory while robot motion does not exceed maximum value of velocity and acceleration.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.75.1-75.1
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• 2014

We present the result of a long-slit spectroscopic study of DG Tau, which is known to emanate parsec-scale outflows. To study the kinematics and physical properties of the jet, we obtained the optical emission lines of $H{\alpha}$, [OI], [NII], and [SII] from HH 158 and HH 702 using the long-slit spectrograph at Bohyunsan Optical Astronomical Observatory. HH 158 shows the peak radial velocity in a range of ~ - 270 to - 30 km s-1. HH 702, located at 11' away from DG Tau shows the velocity of ~ - 80 km s-1. The proper motion velocities of detected knots are estimated through the comparisons with the locations of those knots in the previous studies. We also examine the variations of physical parameters depending on the velocity distribution and the distance from the source using line ratio maps derived from obtained forbidden emission lines.

• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.221-226
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• 1997

This study was carried out for the hull form development of G/T 340ton class high speed fishery patrol ship by Chosun University at the Circulating Water Channel cooperatively with Korea Maritime Service. Same size of 15knots class fishery patrol ship was selected as a parent form (Model number : CU-015), and modified fore and after body to be suitable for the operation at 20 knots. To minimize the breaking wave in the vicinity of fore body at high speed zone, high bulb nose and slender fore body hull form was chosen as an initial condition. Meanwhile, to ensure the engine room space keeping high resistance-propulsion performance, U-type stern hull form was developed.

• Journal of the Korean Mathematical Society
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• v.51 no.4
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• pp.817-836
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• 2014

We develop a topological model of site-specific recombination that applies to substrates which are the connected sum of two torus links of the form T(2, n)#T(2, m). Then we use our model to prove that all knots and links that can be produced by site-specific recombination on such substrates are contained in one of two families, which we illustrate.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.3
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• pp.222-226
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• 2005

A series of model tests carried out at the CWC of WJFEL for the purpose of prediction of resistance for the performance and improvement of resistance by attaching appendage for the ship of 50 knots class planing hull. The resistance performance evaluation has been carried out for the bare hull and for the appendage hull with two different depth of vertical type wedges. In the bare model test, trim and sinkage is calculated for the planing hull and the resistance is calculated. For minimizing the resistance, wedge appendage is attached and tested. Analysis and tests shows that for a 12.5mm wedge, resistance is minimum and overall power tallied to 5636ps.