• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.12
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• pp.3741-3747
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• 1996

This paper presents a method for the inverse dynamic anlaysis of mechanical systems. Actuating forces(or torques) depending on the driving constraints are analyzed in the relative coordinate space using the velocity transformation technique. A systematic method to compose the inverse velocity transformation matrix, which is used to determine the joint reaction forces, is proposed. Two examples are taken to verify the method developed here.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.373-378
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• 2003

This study deals with development of transformation tool for transformation of digital map coordinates systems using by the best fit transformation parameters which are determined between the local geodetic datum and geocentric datum (ITRF2000) in Korea and distortion modelling derived from collocation method. We used 107 control points as a common points. For analyzing the derived parameters, another 83 common points are tested. Finally, the best fit parameters are determined from Molodensky-Badekas model after considering the RMSE, maximum value, minimum values, and 95% confidence interval of residuals. after transformation of best fit parameters and distortion modelling, we could develop transformation tools with advenced accuracy. so it is possible to perform on transformation of digital map with scale 1:5,000. and we tested accuracy eveluation through analysis between transformation results and field results of GPS observation.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.3
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• pp.10-16
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• 1994

This study aimed at measuring the latent heat of phase transformation of S45C carbon steel in quenching and at conducting the analytical researches into the calculation of cooling curves including the latent heat. The temperature of phase transformation of steel and its latent heat are dependant upon the cooling rates at the temperature of A1 phase transformation point. The effect of the latent heat of phase transformation is especially manifest at the cooling curve of center of specimens. The higher the cooling rates became, the lower fell the temperature region of phase transformation. In the figures of cooling rates, the phenomena of cooling rate dropping into zero was caused by the latent heat of phase transformation.

• The Mathematical Education
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• v.40 no.1
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• pp.93-102
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• 2001

The world we live in is called the age of information. Thus communication and computers are doing the central role in it. When one studies the mathematical problem, the use of tools such as computers, calculators and technology is available for all students, and then students are actively engaged in reasoning, communicating, problem solving, and making connections with mathematics, between mathematics and other disciplines. The use of technology extends to include computer algebra systems, spreadsheets, dynamic geometry software and the Internet and help active learning of students by analyzing data and realizing mathematical models visually. In this paper, we explain concepts of transformation, linear transformation, congruence transformation and homothety, and introduce interesting, meaningful and visual models for teaching of a plane transformation geomeoy which are obtained by using Mathematica. Moreover, this study will show how to visualize linear transformation for student's better understanding in teaching a plane transformation geometry in classroom. New development of these kinds of teaching-learning methods can simulate student's curiosity about mathematics and their interest. Therefore these models will give teachers the active teaching and also give students the successful loaming for obtaining the concept of linear transformation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.809-814
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• 2006

In this paper, the modified direct method employing beam transformation technique is proposed in order to efficiently calculate hydroelastic responses of floating structure. Since the proposed method expresses the displacements of three-dimensional structure with those of transformed beam which leads to small number of equations of motion, the method is numerically efficient compared to the conventional direct method. To verify the efficiency of the proposed method a 500 m-long floating structure under wave loads is considered in numerical example. Displacements, bending moments, torsion moments and shear forces are calculated and computing tine is examined. The results are also compared with those of the conventional direct method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.1 s.118
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• pp.17-23
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• 2007

In this paper, the modified direct method employing beam transformation technique is proposed in order to efficiently calculate hydroelastic responses of floating structure. Since the proposed method expresses the displacements of three-dimensional structure with those of transformed beam which leads to small number of equations of motion, the method is numerically efficient compared to the conventional direct method. To verify the efficiency of the proposed method, a 500 m-long floating structure under wave loads is considered in numerical example. Displacements, bending moments, torsion moments and shear forces are calculated and computing time is examined. The results are also compared with those of the conventional direct method.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.265-265
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• 2000

In this paper the systematic modeling method of general wheeled mobile robot is proposed. First we show how to describe kinematics properties of wheeled mobile robot in the method formulating constraint equations using Basic Homogeneous Transform(BHT) which is used mainly the kinematics modeling of manipulator, and, under assumption it's provided part of nullvector in given constraint equations, find kinematics model of mobile robot related to actuators in real robot.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.690-695
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• 2003

The main purpose of this paper is to apply differential transformation method to vibration analysis of Euler-Bernoulli beam with open cracks on elastic foundation. The governing equation of motion of beam with open cracks on elastic foundation is derived. The concept of differential transformation is briefly introduced. The cracks are modeled by massless substitute spring. The effects of the crack location, size and the foundation constants, on the natural frequencies of the beam, are investigated.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.3
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• pp.79-85
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• 2008

This study aims to derive a practical coordinate transformation method for the existing geographic information database. After analyzing the status and problems of existing 1/1,000 digital base map and GIS application database, the transformation parameters are estimated and the accuracy of the transformation is determined based on the transformed coordinates. We analyzed the accuracy of a transformation using the published national transformation coefficients as well as the estimated local transformation coefficients using national and urban control points in a study area. In addition, the 1/1,000 digital base map from aerial triangulation is compared with respect to the coordinates of urban control points. Based on the comparison, the biases on the national control points which were used at the time of digital map generation was analyzed. Then, the accuracy of transformed coordinates based on the world geodetic system using local transformation coefficients estimated from urban control points are determined. We also analyzed the transformation accuracy of underground infrastructure database using the same transformation method as the case of 1/1,000 digital base map. Through this study, it was found that the estimation of transformation coefficients by Molodensky-Badekas using urban control points was suitable for a local government. Furthermore, it was obvious that the accuracy of a 2-dimensional affine transformation was comparable to that of 7 parameter transformation for a local area. Applying the coordinate transformation and bias correction, we could transform GIS application database which was built by an offset surveying based on digital base map within the transformation accuracy of 10 cm. Therefore, it was judged that there will not be a big problem on the transformation of the GIS DB to the world geodetic system.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.255-258
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• 2003

This paper defines Normalized Term Frequency Weighting method for automatic text categorization by using Box-Cox, and then it applies automatic text categorization. Box-Cox transformation is statistical transformation method which makes normalized data. This paper applies that and suggests new term frequency weighting method. Because Normalized Term Frequency is different from every term compared by existing term frequency weighting method, it is general method more than fixed weighting method such as log or root. Normalized term frequency weighting method's reasonability has been proved though experiments, used 8000 newspapers divided in 4 groups, which resulted high categorization correctness in all cases.