• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.49-52
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• 2003

IEEE 802.11 MAC uses a distributed coordination function (DCF) known as carrier sense multiple access with collision avoidance (CSMA/CA) for medium access. Random back-off algorithm helps to avoid the collision. This paper proposes virtual back-off and modified back-off algorithm for reduce a waiting time by back-off and reduce the collision. The modified DCF is consisted of these two algorithms. We expect to reduce the average waiting time of each transmission by using the modified DCF algorithm.

• Journal of Fashion Business
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• v.21 no.5
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• pp.91-108
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• 2017

Interests in 3D virtual clothing technology and its application in online shopping malls are increasing with the advent of the Fourth Industrial Revolution. Most studies on 3D virtual clothing, however, are focused on observing drapes or ease of virtual clothing depending on fabric properties of representative clothing items. Therefore, the purpose of this study is: first, to determine if current input of typical material characteristics in 3D CLO are sufficient to formulate virtual skirts with different front and back silhouettes; second, to determine if subjective appearance evaluation matched physical shape characteristics of those skirts. In this study, appearances of typical cotton, wool, silk, rayon, and polyester skirts with different front and back pattern were compared between actual and virtual clothing depending on fabric materials. Subjective appearance evaluation was conducted by 7 experts regarding similarity between actual and virtual clothing with a 5-point scale. For objective evaluation of the both types of skirt shape, degree of roundness at the cross section, displacement of side seam, position of back waistline, and the number of folds at the skirt back were observed. In the case of cotton and wool, not the subjective appearance evaluation as well as shape characteristics of virtual skirts were well matched to the actual shape of skirts with a few material inputs. However, current material inputs for silk, rayon and polyester were insufficient to cover material differences in formation of virtual skirts with different front and back silhouettes.

• The Research Journal of the Costume Culture
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• v.30 no.3
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• pp.429-443
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• 2022

The purpose of this study is to verify how similar the virtual fit pants are to the actual fit of stretchable pants. Data is produced using a virtual model to apply movements. The results show that in the upright position, the similarity between the appearance of the actual fit and the virtual fit is high. Results are 4.47, 4.13 and 4.33 out of 5 on the front, side, and back, respectively. The base line of the front and back, and the amount of allowance in each part were well reproduced by the model. The texture of the virtual fit was evaluated and found to be similar to the actual fabric. In terms of shape and number of wrinkles with the virtual fit pants, large wrinkles were better expressed than fine wrinkles. After applying movements to the virtual model, the front and side results were similar to the actual fit, but the back results were different. As a result of multiple comparisons, the greatest difference in similarity by movements is found in the center front line. The similarity difference was lower on the side than on the front. The only significant difference after applying movements is in the hip circumference margin. According to movements, the similarity of virtual fit is lower on the back than on the front and side, and the back also has the largest similarity differences to the movements type.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.9
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• pp.940-951
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• 2012

This study evaluates the fit preference of the tailored jacket according to body types for 20's adult women through a comparison of real and virtual fit. A five point fit evaluation scale utilizing a wearer acceptability scale by Shen and Huck was used to evaluate the degree of the preference of real and virtual fit. This scale contained 23 items in three categories: front fit, back fit, and side fit. For each item, 5 responses from 'too tight' fit (1 point) to 'too loose' fit (5 point) were possible. The middle position for each fit criterion indicated a 'good' fit (3 point). The data were analyzed with a t-test using statistical program SPSS 17.0. According to the results, there were no significant differences ($p{\leq}.05$) between the real and virtual fit preference in total measurement items such as front collar, lapel and roll line, front shoulder slope, front armhole, front waist, abdomen, sideseam, hemline, front silhouette, side shoulder, side armhole, side sleeve width, side hip, side silhouette, back collar stand, upper back, back armhole, back waist, back hip, back silhouette except front bust, side waist, and back center back. The factor that caused a difference in the fit preference between the real and virtual fit evaluation was a specific body type such as Body Type A that indicated a small bust circumference and a big hip circumference.

• Fashion & Textile Research Journal
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• v.21 no.2
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• pp.189-202
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• 2019

This study develops a bodice pattern for high school girls aged 17 to 19 that use virtual garment simulation. The study developed a bodice pattern based on the fit evaluation result for two selected bodice patterns. The basic formula of the design method based on the result of 3 times of fit evaluation is as follows: waist back $length=stature/8{\times}1.85cm$, waist front length=waist back length+bust/40+0.7cm, front bust girth=bust/2+4cm, back bust girth=Chest/2+3cm, armscye depth=Chest/4+0.5cm, back interscye length=bishoulder length -1.2cm, front interscye length=back interscye length -1.2cm, front neck width=back neck width -0.3cm. The developed bodice pattern used Bishoulder Length as a criteria for the calculation formula of back interscye length, and back interscye length as a criteria for the calculation formula of front interscye length. The fit evaluation showed the relevance of the bishoulder length, front interscye length, and back interscye length based on a comparison of the calculated figure. A bodice pattern with great body suitability and fitness to high school girls was developed through 3D virtual garment simulation that calculated the application of body proportion to width. This study only analyzed the evaluation result of a virtual model only in a representative form; however, a pattern study is also proposed to compare and analyze the design methods of patterns by body type.

• The Research Journal of the Costume Culture
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• v.19 no.2
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• pp.245-254
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• 2011

The purpose of this study was to develop uniform pattern of obese junior-high school girls by using the virtual twin and 3D virtual garment simulation system. The results were as follows; first, by using 3D virtual garment simulation, new uniform pattern considered obese junior-high school girls was development. The basic numerical formula were as follows; bust girth=B/2+2.5, armhole depth=B/4, front waist girth=W/4+1.8, back waist girth=W/4+1, front hip girth=H/4+1, back hip girth=H/4+1, chest width=chest width+1.5, back width=back width+1 and back neck width 8cm. Second, according to the results of the new uniform pattern's appearance evaluation, it estimated more highly than existing pattern in silhouette and ease amount, confirming that new uniform pattern is appropriate for the obese junior-high school girls. Also, new uniform pattern was evaluated to allow proper space length of bust, waist, abdomen and hip. Virtual models production through 3D body scan data, pattern draft and virtual garment digital program were applied to prototypic design method so as to enhance the fitness of ready-made garments. This study is expected to serve as one of important basic data for ensuing studies that may utilize 3D virtual garment simulation system with 2D patterns, and also for future 3D pattern production program development.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.894-899
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• 2008

Measured sensor datum from a quadruped robotics is commonly used for recognizing physical environment information which controls the posture of robotics. We can advance the ambulation with this sensed information and need to synthesize various sensors for obtaining accurate data, but most of these sensors are expensive and require excessive load for the operation. Those defects can be serious problem when it comes to the prototype's practicality and mass production, and maintenance of the system. This paper suggests virtual sensor technology for avoiding previous defects and presents ways to apply a theory to a walking robotics through virtual sensor information which is trained with several kinds of actual sensor information from the prototype system; the general algorithm is initially based on the neural network theory of back propagation. In specific, we verified a possibility of replacing the virtual sensor with the actual one through a reaction force measurement experiment.

• Fashion & Textile Research Journal
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• v.21 no.1
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• pp.59-66
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• 2019

The purpose of this study was to develop slacks pattern of elderly women aged over 60s by using the virtual twin and 3D virtual garment simulation system. The results were as follows; first, By using 3D Virtual Garment Simulation, new slacks pattern considered elderly women was development. The basic numerical formula were as follows, front waist girth W/4+2+1.5, back waist girth W/4+1.5+0.5, front hip girth H/4+0.75, back hip girth H/4+1.5, front crotch extension H/16-0.5, back crotch extension H/8-1.3, front dart amount 2 and back dart amount 1.5. Second, according to the results of the new slacks pattern's appearance evaluation, it estimated more highly than existing pattern in silhouette and ease amount, confirming that new slacks pattern is appropriate for the elderly women. Also, new slacks pattern was evaluated to allow proper space length of waist, abdomen and hip. Virtual models production through 3D body scan data, pattern draft and virtual garment digital program were applied to prototypic design method so as to enhance the fitness of ready-made garments. The use of the virtual twin made it impossible to comprehend the appearances and ease correspondent to motions. In order to evaluate wearing fitness, therefore, the system should be improved so as to change arm positions and perform various motions.

• Fashion & Textile Research Journal
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• v.12 no.1
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• pp.86-93
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• 2010

The purpose of this study was to develop torso pattern of Middle-aged obese women by using the virtual twin and 3D virtual garment simulation system. The results were as follows; 1. By using 3D Virtual Garment Simulation, new torso pattern considered obese women was development. The basic numerical formula were as follows ; bust girth B/2+5, armhole depth B/6+5, front waist girth W/4+2+0.5, back waist girth W/4+1-0.5, front hip girth H/4+1+0.5, back hip girth H/4+2-0.5, chest width B/6+2.5, back width B/6+2.5 and back neck width B/20+2.5. 2. According to the results of the new torso pattern's appearance evaluation, it estimated more highly than existing pattern in silhouette and ease amount, confirming that new torso pattern is appropriate for the obese women. Also, new torso pattern was evaluated to allow proper space length of bust, waist, abdomen and hip. Virtual models production through 3D body scan data, pattern draft and virtual garment digital program were applied to prototypic design method so as to enhance the fitness of ready-made garments. This study is expected to serve as one of important basic data for ensuing studies that may utilize 3D Virtual Garment Simulation System with 2D patterns, and also for future 3D Pattern Production Program development.

• The Research Journal of the Costume Culture
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• v.19 no.5
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• pp.1009-1018
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• 2011

The purpose of this study was to develop slacks patterns for middle-aged abdomen-obese adult males by using the 3D virtual-twin and virtual-garment simulation system. The criteria for subjects in this study were males who had over $25kg/m^2$ of BMI, over 90cm of waist, and over 0.90 of WHR. A total of 211 adult males who met these criteria were enrolled. The results were as follows: first, a new slacks pattern considerate of abdomen-obese men was development. The basic numerical formula were as follows: front and back hip girth H/4+3.5, front waist girth W/4+1+0.5, back waist girth W/4+1-0.5, front crotch extension H/16, back crotch extension H/8-0.5, front pleats amount 2.7, and back dart amount 1.5. Second, according to the results of the new slacks patterns appearance evaluation, the new slacks pattern scored more highly than the existing pattern in silhouette and ease amount, confirming that the new slacks pattern is appropriate for the abdomen-obese men. Also, the new slacks pattern was evaluated allowing proper space length of waist, abdomen and hip. Virtual models of production through data from a 3D body scan, pattern draft and virtual garment digital program were applied to a prototypic design method in order to enhance the fitness of ready-made garments. The use of the virtual twin made it impossible to comprehend the appearances and ease correspondent to motions. In order to evaluate wearing fitness, therefore, the system should be improved so as to change arm positions and perform various motions.