• Journal of the Korean Society for Precision Engineering
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• v.15 no.5
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• pp.128-136
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• 1998

A mathematical model for investigating the form generation mechanism in the centerless infeed grinding process is described. For 3-D modeling of form generation, contact points are assumed to be on least squares contact lines at the grinding wheel, regulating wheel, and work-rest blade. Using force and deflection analysis, the validity of this assumption is shown. Based on the 2-D simulation model developed in the previous work and the least squares contact line assumption, a 3-D model is presented. To validate this model, simulation results were compared with the experimental works. The experiments and computer simulations were carried out using three types of cylindrical workpiece shapes with varying flat length. The experimental results agree well with the simulation. It can be seen that the effect of flat end propagated to the opposite end through workpiece reorientation.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.5
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• pp.137-144
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• 1998

A mathematical model for investigating the form generation mechanism in the centerless thrufeed grinding process is described. The length of the contact line and the magnitude of the grinding force between the grinding wheel and workpieces vary with the change of the axial location of the current workpiece during grinding. Thus, a new coordinate system and a grinding force curve of previous and/or following workpieces are introduced to treat the axial motion. Experiments and computer simulations were carried out using three types of cylindrical workpiece shapes. To validate this model. simulation results are compared with the experimental results.

• Korean Journal of Crystallography
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• v.9 no.2
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• pp.120-124
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• 1998

N-tert-Butyl-2-(1-acetoxy-2-fluoro-1-butyl)benzenesulfonamide의 분자 및 결정구조를 X-선회절법으로 연구하였다. 결정의 공간군은 P21/c이고, 단위포 상수는 a=8.583(2) , b=14.674(2) , c=14.703(2) , β=103.23(1)0, Z=4, V=1802.6(5) 3, Dc=1.27 Mgm-3이다. 회절반점들의 세기는 Rigaku AFC-5 Diffractometer로 얻었으며, graphite로 단색화한 Cu-KαX-선을 사용하였다. 분자구조는 직접법으로 풀었으며 최소자승법으로 정밀화하였다. 최종신뢰도 R값은 2472개의 회절반점에 대하여 0.069였다. 분자 내에 N(7)과 O(4)사이에 1개의 수소결합[2.990(4) ]을 갖으며, C(14)와 C(15)는 반대배열을 갖고 있다. 분자간 가장 인접한 거리는 3.465(5) [C(19) O(5)] (symmetry code: -x, y+1/2, -z+1/2)로 분자간 접촉은 van der Waals 힘에 의해 결합되어 있다.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.300-306
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• 2012

In this paper, we propose a vision based hand motion recognition method for an untouchable user interface of smart devices. First, an original color image is converted into a gray scaled image and its spacial resolution is reduced, taking the small memory and low computational power of smart devices into consideration. For robust recognition of hand motions through separation of horizontal and vertical motions, the horizontal principal area (HPA) and the vertical principal area (VPA) are defined respectively. From the difference images of the consecutively obtained images, the center of gravity (CoG) of the significantly changed pixels caused by hand motions is obtained, and the direction of hand motion is detected by defining the least mean squared line for the CoG in time. For verifying the feasibility of the proposed method, the experiments are carried out with a vision system.