• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.71-78
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• 1999

The determination of the optimum biarc curve passing through a given set of points along involute curve is studied. The method adopted is that of finding the optimum number of span and the optimum length of the span such that error between the biarc curve and involute curve minimum. Iterative method is effectively used to find the optimim number and length of the span on involute curve with reduced length of NC-code.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.578-582
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• 2005

In this study, the conceptual foundation and development process of the Antecedent soil Moisture Condition(AMC) in SCS runoff curve number method are reviewed. Although the runoff volume is very sensitive with AMC condition, the AMC class limits developed in SCS(1972) are used in rainfall-runoff analysis without careful consideration. Tn this study, following the SCS curve number development process, rainfall-runoff characteristics of the Jang-Pyung subbasin subject to the Pyung-Chang River basin are analyzed to evaluate the reasonability of the AMC class limits at present. The New AMC class limits are proposed by the sensitive analysis of the antecedent rainfall - curve number value. As a result, the classification value of AMC-I with II is 22mm of antecedent 5-day rainfall amount, and the classification of AMC-II with III is 117mm in growing season. When the New AMC class limits are applied to Jang-Pyung subbasin, AMC probability distribution shows that the AMC-II has increased remarkably even though the AMC-I has a little higher value. But the AMC-III has the smallest one. According to the conceptual basis of the curve number method, the AMC probability distribution, the New AMC class limits adopted, gives reasonable results.

• Water for future
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• v.24 no.2
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• pp.97-108
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• 1991

A number of different curve numbers are estimated, and three of them are the basin or composite curve numbers (CN-II and CN-III) evaluated from hydrologic soil cover complex, the observed curve numbers computed from rainfal1-runoff observations and the basin median curve numbers as a median of the observed curve numbers. Based on the observed runoff, CM-II underestimates the effective rainfall meanwhile CN-III overestimates. Hence, for the improvement in estimating effective rainfall, a modulating curve number may be defined as a value in between CN-II and CN-III. Basin median curve numbers produces the closest result to the observed runoff and therefore it can be adopted as a representative curve number for gaged basin.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.9
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• pp.48-53
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• 1999

In this paper, a practical method for design and machining of cycloid gear was investigated. Based on the proposed method, a systematic program was developed for automatically designing the tooth profiles of epicycloid and hypocycloid gears for the case fo one difference between the number of teeth of cycloid gear and the number coordinates of tooth profiles and pressure angles. The error analysis between cycloid curve and Biarc curve was performed to show the effective method of equidistant partitioning of cycloid curve so that efficient method of Biarc curve fitting was also proposed for the partitioned curve.

• Korean Journal of Hydrosciences
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• v.4
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• pp.21-32
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• 1993

The estimates of both runoff depth and peak runoff by the basin runoff curve numbers, which are CN-II for antecedent moisture condition- II and CN -III for antecedent moisture condition-III, obtained from hydrological soil-cover complexes of 26 watersheds are investigated by making use of the observed curve numbers, which are median curve number and optimum curve number, computed from 250 rainfall-runoff records. For gaged basins the median curve numbers are recommended for the estimation of both runoff depth and peak runoff. For ungaged basin, found is that for the estimate of runoff depth CN-II is adequate and for peak runoff CN-II is suitable. Also investigated is the variation of the runoff curves during storms. By the variable runoff curve numbers, the prediction of runoff depth and peak runoff can be improved slightly.

• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.633-645
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• 2003

The techniques of GIS and remote sensing are being applied to hydrology, geomorphology and various field of studies are performed by many researcher, related those techniques. In this paper, curve number change detection is tested according to soil map and land cover in mountain area. Neural networks method is applied for land cover classification and GIS for curve number calculation. The first, sample area are selected and tested land cover classification, NN(84.1％) is superior to MLC(80.9％). So we selected NN with land cover classifier. The second, curve number from the land cover by neural network classifier(57) is compared with that(curve number) from the land cover by manual work(55). Two values are so similar. The third, curve number classified by NN in sample area was applied and tested to whole study area. As results of this study, it is shown that curve number is more exact and efficient by using NN and GIS technique than by (using) manual work.

• Korean Journal of Computational Design and Engineering
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• v.11 no.1
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• pp.1-10
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• 2006

This paper addresses B-spline curve approximation of a set of ordered points to a specified toterance. The important issue in this problem is to reduce the number of control points while keeping the desired accuracy in the resulting B-spline curve. In this paper we propose a new method for error-bounded B-spline curve approximation based on adaptive selection of dominant points. The method first selects from the given points initial dominant points that govern the overall shape of the point set. It then computes a knot vector using the dominant points and performs B-spline curve fitting to all the given points. If the fitted B-spline curve cannot approximate the points within the tolerance, the method selects more points as dominant points and repeats the curve fitting process. The knots are determined in each step by averaging the parameters of the dominant points. The resulting curve is a piecewise B-spline curve of order (degree+1) p with $C^{(p-2)}$ continuity at each knot. The shape index of a point set is introduced to facilitate the dominant point selection during the iterative curve fitting process. Compared with previous methods for error-bounded B-spline curve approximation, the proposed method requires much less control points to approximate the given point set with the desired shape fidelity. Some experimental results demonstrate its usefulness and quality.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.719-723
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• 2002

The purpose of this study is to suggest the correlation of single-number ratings for sound insulation by floor impact. As a assessment method of impact sound insulation. we selected the IIC contour of ISO, A weighted sound level. Inverse A-weighting curve and L-Index of japanese industrial standard. And we estimated the single-number ratings by application the measured data of impact sound level to each method. The results showed that the coefficients of determination between each two single-number ratings were very high (more than 0.9169). And In the condition of same assessment method, the coefficient of determination for light-weight impact sound was higher than that for heavy-weight impact sound.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.12
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• pp.1984-1994
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• 1989

Techniques for approximating digitalcurves by polygonal lines are a valuable tool for image analysis and data compression. S. Shilien proposed a method for segmenting a digital curve into digital straight line segments digital straight line segments which are not satisfied with the structural properties, and have more than one break point by Shilien's method. Here, the structural representation of digital straight lines and digital staight line segments is described. And a method for segmenting a digital curve into digital straight line segments which are not satisfied with the structural properties, and have more than one break point by Shilien's method. Here, the structural representation of digital straight lines and digital staight line segments is described. And a method for segmenting a digital curve into digital straight line segments which may be not satisfied with the structural properties is proposed. The number of break points extracted by this method is less than that by S. Shilien's method from the digital curve which includes the digital straight line segments not satisfied with the structural properties.

• Structural Engineering and Mechanics
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• v.34 no.1
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• pp.85-95
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• 2010

In this paper, numerical solution of the singular integral equation for the multiple curved branch-cracks is investigated. If some quadrature rule is used, one difficult point in the problem is to balance the number of unknowns and equations in the solution. This difficult point was overcome by taking the following steps: (a) to place a point dislocation at the intersecting point of branches, (b) to use the curve length method to covert the integral on the curve to an integral on the real axis, (c) to use the semi-open quadrature rule in the integration. After taking these steps, the number of the unknowns is equal to the number of the resulting algebraic equations. This is a particular advantage of the suggested method. In addition, accurate results for the stress intensity factors (SIFs) at crack tips have been found in a numerical example. Finally, several numerical examples are given to illustrate the efficiency of the method presented.