• Transactions of Materials Processing
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• v.9 no.3
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• pp.313-319
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• 2000

Finite element analysis is carried out for simulation of the multi-stage elliptic cup drawing process with the large aspect ratio. The analysis incorporates with shell elements for an elasto-plastic finite element method with the explicit time integration scheme. For the simulation, LS-DYNA3D is utilized for its wide capability of solving forming problems. The simulation result shows that the non-uniform drawing ratio at the elliptic cross section ad the small shoulder radius cause failure such as tearing and wrinkling. The result suggests the guideline to modify the tool shape for prevention of the failure during the drawing process.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1613-1617
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• 2009

As demand regarding a recent energy-saving rises, the using ratio of the aluminum plate in manufacturing of a railroad vehicle has been increasing. The aluminum structure to be applied to a railroad vehicle is divided to single skin and double skin, and the main aluminum product is mainly Al 6005 extrude and Al 5083 rolled in domestic market. The Al 6005 alloy is applied heat treatment in order to improve the strength of material. Therefore there is the disadvantage that the strength of welding zone decreases compare with base material's if you apply to fusion welding like MIG(metal inert gas) welding. In this paper we tried to apply friction stir welding to solve these problems. In this study we investigated how tensile strength and fatigue strength were changed in case of changing the shoulder diameter of thread tool.

• Journal of Korea Multimedia Society
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• v.18 no.1
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• pp.71-80
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• 2015

Many researches have been studied to overcome the weak points in authentication schemes of mobile devices such as pattern-authentication that is vulnerable for smudge-attack. Since random-pattern-lock authenticates users by drawing figure of predefined-shape, it can be a method for robust security. However, the authentication performance of random-pattern-lock is influenced by input noise and individual characteristics sign pattern. We introduce an optimization method of user input direction to increase the authentication accuracy of random-pattern-lock. The method uses the likelihood of each direction given an data which is angles of line drawing by user. We adjusted recognition range for each direction and achieved the authentication rate of 95.60%.

• The Research Journal of the Costume Culture
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• v.8 no.3
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• pp.460-476
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• 2000

The purpose of this study was, accordingly, to examine male college student's general body consciousness and their actual condition of wearing clothing, as it's assumed that clothing, which everyone must always wear, might be effective in making up for the physical defect. The findings of this study were as follows : 1. Male College Students'Body Consciousness : They expressed some dissatisfaction with their own body, and they were most discontented with their height, among their bodies. They thought of the western-style shape as an ideal one, as what's considered by them to be ideal was thinner a little than them, being taller with wider shoulder, longer legs, smaller and white face. 2. Male College Students'Characteristics of Clothing Purchasing Behavior : In purchasing clothing, male college students were slightly sensitive about the physical part with which they wasn't satisfied. The clothing pattern preferred by them was an abstract one, and their favorite color was white or black. The greatest number of them put most emphasis on design in buying clothing, and they purchased clothing mainly at special fashion shop. On the whole, they showed an affirmative response toward wearing Korean costume, and they also had a positive opinion about the purchase of reformed Korean dress for everyday life. 3. Male College Students'Characteristics of Wearing Clothing : They appeared not to consider making up for physical weakness. Male college students favored aloha shirt and trousers when they went out. Male college students purchase clothing in consideration of individual, manly, classical, tender, or comfortable factors. 4. Relationship of Body Consciousness to Wearing Behavior : The degree to which they considered covering up physical weakness in wearing clothing was examined, by dividing them into two groups : one was a group that thought their own shape normal, and the other was a group that didn't think of their own shape as normal. As a result, both groups appeared not to consider covering up physical weakness.

• Fashion & Textile Research Journal
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• v.11 no.5
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• pp.788-798
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• 2009

This study aims to develop a highly reproducible, optimal frame design algorithm using variations in the curvature of armscye circumference, which will provide the basics for remodeling the 3D human body shape with the concept of reverse design used to develop total contents for the apparel industry. 1. The results of the experiment proved that ratio value was significantly efficient than absolute value of curvature variation to extract feature points in the armscye circumference 2. For the shoulder(1st and 2nd quadrant) and front armhole(3rd quadrant) parts of the armscye circumference, frame remodeling with the positive point of inflection led to the completion of a highly reproducible frame. 3. Similarly, even for the rear armhole part(4th quadrant) in the armscye circumference, it was found that frame remodeling using the positive maximum point of inflection resulted in highly reproducible body shape with the maximum point of inflection situated within the range of split angles $305^{\circ}{\sim}330^{\circ}$, while frame remodeling using simultaneously the two largest points of inflection including maximum point of inflection led to highly reproducible body shape with the maximum point of inflection out of the range $305^{\circ}{\sim}330^{\circ}$. 4. Based upon the optimal frame design algorithm developed in this study, section-specific feature points in the armscye circumference were extracted depending on the rate of curvature variation and remodeling with spline curves was conducted. The results indicate a remarkably high reproducibility(98.6%) and suggest that the algorithm developed in this study is suitable for human body modeling.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.11
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• pp.1768-1773
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• 2009

This study determines the body size of preteen children and conducts questionnaire investigations into the awareness of real purchasers or parents of and satisfaction with children's clothes and fit, in order to provide the basic data for planning and setting up the size range for the preteens market in which the sales of children clothes are gradually increasing. The findings of this study are as follow: Analyzing the obesity of the children against the Rohrer index showed that almost 30% of the subjects were obese children and that it is necessary to research the sizes of the clothes for obese children. It was also found that older children selected a more appropriate clothe size. Investigations into the awareness of children on their body image found that there was a significant difference in the perception of body shape, body weight, shoulder breath, arm thickness, chest girt, waist girth, hip girth, and thigh thickness. Slim or standard type children had the greatest consideration for the length of clothes to purchase while obese children had the greatest consideration for bosom size and waist girth. However, in terms of the association between fitness and size selection, obese children did not select a bigger size but an appropriate one for their body. The findings show that it is imperative to develop appropriate size clothes for obese children.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.06a
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• pp.55-60
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• 2006

Draw-bead is applied to control the material flow in a stamping process and improve the product quality by controlling the draw-bead restraining force (DBRF). Actual die design depends mostly on the trial-and-error method without calculating the optimum DBRF. Die design with the predicted value of DBRF can be utilized at the tryout stage effectively reducing the cost of the product development. For the prediction of DBRF, a simulation-based prediction model of the circular draw-bead is developed using the Box-Behnken design with selected shape parameters such as the bead height, the shoulder radius and the sheet thickness. The value of DBRF obtained from each design case by analysis is approximated by a second order regression equation. This equation can be utilized to the calculation of the restraining force and the determination of the draw-bead shape as a prediction model. For the evaluation of the prediction model, the optimum design of DBRF in sheet metal forming is carried out using response surface methodology. The suitable type of the draw-bead is suggested based on the optimum values of DBRF. The prediction model of the circular draw-bead proposes the design method of the draw-bead shape. The present procedure provides a guideline in the tool design stage for sheet metal forming to reduce the cost of the product development.

• Fashion & Textile Research Journal
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• v.16 no.2
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• pp.255-265
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• 2014

This study developed and proposed a pattern that can fit the body and compensate for the defects of the body type by applying shoulder princess line to the torso pattern and including formative characteristics of each object on the study of body shape's change in 40-59 year old middle aged women. The results of this study are as follows; First, according to the analysis of 'Size Korea 2010' such as average, standard deviation, minimum value, and maximum value of 48 items, women showed increase in most of the items except height as they became aged. Second, factor analysis was made to understand the shape component factors of middle aged women and to use them for the body type classification. Third, cluster analysis was made according to the shape of front and sides which should be considered in pattern production based on the factor analysis results, and the body type with the measurement values most similar to the average of direct measurement of 'Size Korea 2010' was set as standard. Fourth, in designing torso patterns through the $1^{st}$ and the $2^{nd}$ wearing experiments according to the body type, body shapes such as Chest Circumference, Waist Circumference, Hip Circumference, and Waist Back Length were considered in pattern design, goodness-of-fit was enhanced with difference in margin according to body type and different margins in front and back, and fitting satisfaction was improved by applying princess line.

• Fashion & Textile Research Journal
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• v.14 no.1
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• pp.109-121
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• 2012

This study aims at developing ergonomics patterns for the sleeve of structural firefighting protective clothing through 3D motion analysis in order to ensure efficiency and safety of firefighters who are exposed to harmful environment at work. A new research pattern was developed by applying the total results of 3D motion analysis, changes of body surface length measurements, and 2D data on 3D body shape analysis on the size 3 patterns of the existing coat sleeve. For the sleeves, we used the body surface length of the range of shoulder's flexion and the joint angle of the range of wrist's ulnar deviation. And for the production of structural firefighting protective clothing using the research pattern, we recruited a recognized producer of structural firefighting protective clothing designated by KFI. Unlike everyday clothes, structural firefighting protective clothing should be able to fully protect the wearers from the harmful environment that threatens their lives and should not cause any restrictions on their movement. Therefore, the focus of research and development of such protective clothing should be placed on consistent development of new technologies and production methods that will provide protection and comfort for the wearer rather than production cost reduction or operational efficiency. This study is meaningful as it applied 3D motion analysis instead of the existing methods to develop the patterns. In particular, since 3D motion analysis enables the measurement of the range of motion, there should be continuous research on the development of ergonomics patterns that consider workers' range of motion.

• Fashion & Textile Research Journal
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• v.25 no.5
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• pp.603-614
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• 2023

Body shape is the most influential factor in determining the quality of clothing fit. Women's body shape begins to change significantly in their mid-30s; therefore, this study aimed to classify and analyze the torso shapes of women aged 35-54 years. This study selected 200 3D body scans of women from the 8th Size Korea Survey database (2021). Using the Grasshopper algorithm developed in a previous study, 17 landmarks were automatically detected and 57 measurement values were generated. Using principal component analysis, 11 components (overall body size, upper body length, back protrusion, upper body slope, neck position, neck inclination, hip length, bust prominence, abdominal prominence, shoulder slope, and buttock prominence) were extracted. Three torso types were identified using K-means cluster analysis. The three body types were significantly different on nine component scores. Among the three torso types, Type 1 (37.5%) has the longest upper body and the flattest back and hips. Type 2 (31.0%) has the most curved back and forward upper body. Its abdomen is the flattest, and its shoulders are the most sloped. Type 3 (31.5%) has the shortest upper body, the most protruding hips, and the largest overall body size. This paper proposes two discriminant functions for identifying a new person's torso type.