• International Journal of Aeronautical and Space Sciences
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• v.9 no.1
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• pp.1-30
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• 2008

When the stagnation temperature of a perfect gas increases, the specific heats and their ratio do not remain constant any more and start to vary with this temperature. The gas remains perfect; its state equation remains always valid, except, it is named in more by calorically imperfect gas. The aim of this work is to trace the profiles of the supersonic axisymmetric Minimum Length Nozzle to have a uniform and parallel flow at the exit section, when the stagnation temperature is taken into account, lower than the dissociation threshold of the molecules, and to have for each exit Mach number and stagnation temperature shape of nozzle. The method of characteristics is used with the algorithm of the second order finite differences method. The form of the nozzle has a point of deflection and an initial angle of expansion. The comparison is made with the calorically perfect gas. The application is for air.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.91-93
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• 2005

Forming sheet metal by laser-induced thermal stresses (laser forming) has been extensively studied, and the research has focused on two-dimensional geometries using a multi-pass straight line scan. Recently there came out some useful studies or three-dimensional laser forming which is applied to doubly curved shapes. The task of 3D laser forming sheet metal is to determine a set of process parameters such as laser scanning paths, laser power and scanning speed that will make a given shape. New method for laser forming of a doubly curved surface by using geometrical information was proposed and verified by experiments. This method shows good performance in the sense of calculation time and accuracy compared to the inherent strain method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.1
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• pp.74-80
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• 2010

The purpose of reverse engineering design using 3D measurement data is an accurate reconstruction of real body. In oder to accomplish this object, it is important that creating exact extracting edges should be studying out first of all. This study used edge-based method to find out edge point from the measuring point data. The characteristics are analysed using the mean curvature block method on the fitting NURBS curve and defined edges through block removal condition. The results showed that only using the NURBS curve of maximum curvature analysis to define correct edge of real geometry is limited, but this segmentation approach provides simplified necessary condition for edge classification, and an effectiveness to classify a straight line, curves and fillets etc.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.12
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• pp.1601-1609
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• 1988

In the control of the robotic manipulators, the variable structure control method for the set point Regualation has an advantage of the insensitivity about parameter variations and disturbances. When the robotic manipulatores are controlled by a point-to-point scheme, no path constraint is considered. Thus, the variable structure control method will be effectively applied only if the trajectory of the robot hand is estimated precisely. In this paper, the joint trajectories in the joint space and the hand trajectory in the cartesian space are calculated by the variable structure control method, and an algorithm is suggested to elaborate the deviation error of the robot hand from a straight line path. The result of this study will become a base of the effective path planning about robotic manipulators with the variable structure control concept.

• The Journal of the Acoustical Society of Korea
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• v.20 no.8
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• pp.74-80
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• 2001

Because of ocean waves, swell, steering corrections, etc, the hydrophones of a towed array will not live along a straight line. However the degradation of bearing estimation performance occurs when beamforming is carried out on the hydrophone outputs of an acoustic towed array which is not straight. So it is required to estimate the shape of the array for the improved beamformer output. In this paper, an iterative array shape estimation technique is presented, which is based on the use of the least squares polynomial fitting to the data from heading sensors. The estimation error and the influence of deformations on the performance of the conventional beamformer output are investigated. Finally, the suggested method is applied to the real system in order to investigate the applicability.

• Journal of the Semiconductor & Display Technology
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• v.11 no.1
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• pp.79-83
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• 2012

We use adaptive method and determine threshold coefficient so that the algorithm could decide a suitable binarization threshold coefficient of the image to detecting a marker; therefore, we solve the light influence on the shadow area and dark region. In order to improve the speed for reducing computation we created Integral Image. The algorithm detects an outline of the image by using canny edge detection for getting damage or obscured markers as it receives the noise removed picture. The strength of the line of the outline is extracted by Hough transform and it extracts the candidate regions corresponding to the coordinates of the corners. Markers extracted using the equation of a straight edge to find the coordinates. By using the equation of straight the algorithm finds the coordinates the corners. of extracted markers. As a result, even if all corners are obscured, the algorithm can find all of them and this was proved through the experiment.

• Korean Journal of Applied Biomechanics
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• v.28 no.2
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• pp.93-100
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• 2018

Objective: The purpose of this study is to analyze the kinematic characteristics of the national speed skaters in the curve phase of 500-m race. Method: Seven national skaters participated in the study. Race images were acquired using a high - speed camera, and the three-dimensional motion was analyzed. Results: For skaters, whose average velocity in the curve phase is high, the velocity of entry into the straight phase was also fast. The fast skaters showed a larger maximum angle of extension of the knee joints than the relatively slow skaters, and the trunk ROM was smaller. Fast skaters tended to match the timing of the movement of the lower limb with the pelvis, while slow skaters tended to rotate the left pelvis backward. The velocity of the curve phase did not show a clear relationship with stroke time, average trunk angle, and lap time. Conclusion: It is important to skate close to the inner line, keep the trunk ROM below 10 degrees, extend the knee angle to over 160 degrees, and match the movement of the pelvis and lower limb to accelerate in the curve phase. The average velocity of the curves was fast for many athletes, but the competition rankings were low. Therefore, it is possible to improve the performance by optimizing the start technique, the running characteristics of the straight phase, and the physical factors.

• Fashion & Textile Research Journal
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• v.20 no.3
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• pp.266-278
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• 2018

This study investigated the transformation of the Chanel jacket by looking at clothing design and constructional components. This study explored Chanel jacket's designs from 2001 S/S to 2016-17 F/W, and collected designs from Samsung Design Net and Vogue. The study used 690 designs with the following results. First, in the silhouette of the Chanel jacket, straight silhouette and hourglass silhouette had the most; in addition, in the length, hip line and under hip line were in order. Second, in case of collar and neckline, the form of a non-collar was the most and revealed the persistence of round neckline which is the basic style of a Chanel jacket. Third, in the shape of sleeves, the loose-fit straight sleeves, wide sleeves, and cocoon sleeves appeared most often. In method of closure, button, zipper were in order, and snaps or without closure appeared. Fourth, in the form of braids, various forms such as twisted yarns, leashes, or lace were used, and patch pockets were mainly used in pockets. Chanel maintains its original design by using various methods. Chanel tried to improve activity and functionality through silhouettes, lengths, necklines, and sleeves. The unchanging expression of the world of Chanel will continue to display and inherit future value. This study can provide Chanel's unique characteristics and new ideas that can transform their origins for jacket design.

• Journal of the Korea Fashion and Costume Design Association
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• v.12 no.3
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• pp.57-71
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• 2010

This study is to understand the actual condition of design and material of peanut-shaped diaper with looking at the types and characteristics of baby cloth diapers and domestic peanut-shaped diapers registered in the Patent Office. Furthermore, it is to suggest the basic data for designing more functional and comfortable cloth diapers. Here are the research result on the actual condition of design and material of baby cloth diapers. Firstly, 11 cloth diapers registered in the Patent Office can be divided into panty-shaped and straight line-shaped diapers. There are 7 kinds of panty-shaped cloth diapers which satisfy both the convenience of a disposable diaper and sanitation of a cloth diaper, and 4 kinds of straight line-shaped cloth diapers that minimize the weaknesses of existing cloth diapers. Secondly, domestic peanut-shaped cloth diapers can be divided into peanut-shaped, inserted, winged, velcro-attached diapers. Among 23 kinds of peanut-shaped cloth diapers from 16 companies, there are 12 kinds of peanut-shaped diapers which consist of layers of cloth to make peanut shape. There are 6 kinds of inserted diapers that insert extra diapers or handkerchiefs in between two sheets of cloth diapers and 3 kinds of winged diapers designed to shorten drying time with sawing only one side of several layered sheets. Also, there are 2 kinds of velcro-attached diapers that are removable according to the amount of excreta. Commonly used materials are cotton woven of diamond jacquard and knit of diamond Hole Stitch or Plain Stitch. And for handing the edge of diaper, the method of wrapping up the edge with cotton woven or knit bias is used.

• Journal for History of Mathematics
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• v.31 no.2
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• pp.73-91
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• 2018

This study begins with the awareness of problem that the education of mathematics teachers has failed to link the limit and the infinite set conceptually. Thus, this study analyzes the historical and reciprocal development of the limit and the infinite set, and discusses how to improve the education of these concepts and their relation based on the outcome of this analysis. The results of the study confirm that the infinite set is the historical tool of linking the limit and the real numbers. Also, the result shows that the premise of 'the component of the straight line is a point.' had the fundamental role in the construction of the real numbers as an arithmetical continuum and that the moral certainty of this premise would be obtained through a thought experiment using an infinite set. Based on these findings, several proposals have been made regarding the teacher education of awakening someone to the fact that 'the theoretical foundation of the limit is the real numbers, and it is required to introduce an infinite set for dealing with the real numbers.' in this study. In particular, by presenting one method of constructing the real numbers as an arithmetical continuum based on a thought experiment about the component of the straight line, this study opens up the possibility of an education that could get the limit values psychologically connected to the infinite set in overcoming the epistemological obstacle related to the continuum concept.