• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.108-114
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• 2012

We propose a dispersive finite-difference time domain(FDTD) algorithm suitable for the electromagnetic analysis of the human body. In this work, the dispersion relation of the human body is modeled by a quadratic complex rational function(QCRF), which leads to an accurate and efficient FDTD algorithm. Coefficients(involved in QCRF) for various human tissues are extracted by applying a weighted least square method(WLSM), referred to as the complex-curve fitting technique. We also presents the FDTD formulation for the QCRF-based dispersive model in detail. The QCRFbased dispersive model is significantly accurate and its FDTD implementation is more efficient than the counterpart of the Cole-Cole model. Numerical examples are used to show the validity of the proposed FDTD algorithm.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.679-682
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• 1988

From the viewpoint of general recognition system, B-spline is introduced for the approximation and recognition of human profile contours. Profile contour is approximated to the cublic B-spline curve by least square fitting so that B-Spline nodes nearly correspond with the curvature extrema of the contour. This method is designed for the spline to be good features in recognition, and also showed good approximation compared with the variants of B-spline appraximation.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.421-424
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• 1999

Automatic human face detection in a complex background is one of the difficult problems In this paper. we propose an effective automatic face detection system that can locate the face region in natural scene images when the system is used as a pre-processor of a face recog- nition system. We use two natural and powerful visual cues, the color and the human head shape. The outline of the human head can be generally described as being roughly elliptic in nature. In the first step of the proposed system, we have tried the approach of fitting the best Possible ellipse to the outline of the head In the next step, the method based on the human skin color space by selecting flesh tone regions in color images and histogramming their r(＝R/(R＋G＋B)) and g(＝G/R＋G＋B)) values. According to our experiment. the proposed system shows robust location results

• Progress in Medical Physics
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• v.6 no.2
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• pp.83-92
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• 1995

The T1 mapping of an human anatomy may give a characteristic contrast among the various tissues and the normal/abnormal tissues. Here, the methodology of constructing T1 map out of several images with different TRs, will be described using non-linear curve fitting. The general curve fitting algorithm requires the initial trial values T1t and Mot for the variables to be fitted. Three different methods of suppling the trial T1t and Mot are suggested and compared for the efficiency and the accuracy. The curve-fitting routine was written in ANSI C and excuted on a SUN workstation. Several distilled-water phantoms with various concentrations of Gd-DTPA were prepared to examine the accuracy of the curve-fitting program. An MR image was used as the true proton density image without any random noise, and several images with different TRs were generated with the theoretical T1 relaxation times 250, 500, and 1000msec. The random noise of 1, 5, and 10％ were embedded into the simulated images. These images were used to generate the T1 map, and the resultant T1 maps for each T1 were analyzed to study the effect of the random noise on the T1 map.

• Proceedings of the KSMRM Conference
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• 2006.11a
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• pp.82-82
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• 2006

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.10
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• pp.1050-1057
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• 2012

This study helps develop a cool body armor that maintains a tight-fit configuration to the body surface and evaluates the performance of newly developed body armor in a wear test. Three types of body armor were used for evaluation. One was a tight fitting body armor that was constructed to improve the degree of fit and ease of movement for Korean soldier using 3D technology. Another was ventilating body armor with attached spacers on the shoulder to reduce the thermal stress on the soldier. The third was a prevailing body armor produced by a Korean body armor company. In order to evaluate the performance of the body armor, a human wear test, a thermal mannequin test, and computational fluid dynamics (CFD) were executed. Five subjects participated in the wear test. Subjective wear sensation, total amount of sweat and dynamic change of clothing microclimate were observed during and after exercise on a treadmill; subsequently, it was found that subjects rated tight fitting body armor and ventilating body armor lighter, drier, and easier to move than the conventional body armor (p<.05). Total amount of sweat was the least in the case of ventilating body armor. The thermal resistance and vapor resistance of the ventilating body armor were improved remarkably. In addition, the skin temperature of the ventilating body armor with spacers was lower than the tight fitting body armor by at least $1^{\circ}C$ in the CFD result. It is noted that thermal-wet comfort of the 3D body armor with ventilating feature is superior to the conventional body armor, especially when the ventilating channel is not closed due to a backpack.

• Korean Journal of Applied Biomechanics
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• v.23 no.1
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• pp.53-62
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• 2013

The methods of fitting a circle to measured data, geometric fit and algebraic fit, have been studied profoundly in various areas of science. However, they have not been applied exactly to a biomechanics discipline for locating the center of rotation of a human joint. The purpose of this study was to generalize the methods to fitting spheres to the points in 3-dimension, and to estimate the center of rotation of a hip joint by three of geometric fit methods(Levenberg-Marquardt, Landau, and Sp$\ddot{a}$th) and four of algebraic fit methods(Delogne-K${\aa}$sa, Pratt, Taubin, and Hyper). 1000 times of simulation experiments for flexion/extension and ad/abduction at an artificial hip joint with four levels of range of motion(10, 15, 30, and $60^{\circ}$) and three levels of angular velocity(30, 60, and $90^{\circ}$/s) were executed to analyze the responses of the estimated center of rotation. The results showed that the Sp$\ddot{a}$th estimate was very sensitive to the marker near the center of rotation. The bias of Delogne-K${\aa}$sa estimate existed in an even larger range of motion. The Levenberg-Marquardt algorithm of geometric fit and the Pratt of algebraic fit showed the best results. The combination of two methods, using the Pratt's estimate as initial values of the Levenberg-Marquardt algorithm, could be a candidate of more valid estimator.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.449-458
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• 2011

There are many functional methods for estimating the mean axis of rotation of a joint. However, it is still a controversial issue which method is superior. The purpose of this study was to compare functional methods for estimated axes of rotation from synthetic data. The comparison was made in terms of suitabilities on describing humans in sports. For a more practical situation, the axis error as well as measurement and marker movement error were applied to generated data. Simulations having 1000 times of 80 rotational displacements were performed. The functional methods used in the study were two transformation methods, two fitting methods, and one more transformation method called M. The M method is a combination of S$\ddot{o}$derk & Wedin(1993) and Mardia & Jupp(2000). Another factor of the study was angular velocity with levels of .01, .025, .05, .5 and 1 rad/s. The method M resulted in unbiased, stable, and consistent axis of rotation vectors in all levels of angular velocity except .01 rad/s. Therefore, the method M had the highest validity and reliability of all the methods. The fitting methods were very sensitive in small angular velocities and stable only in the velocities of more than .5 rad/s. The most suitable method for analyzing human motion by using marker photogrammetry is M.

• Fashion & Textile Research Journal
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• v.19 no.6
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• pp.749-758
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• 2017

The purpose of the present study is to develop a grading deviation, which is appropriate for the body type of women in thirties, by analyzing the three-dimensional body type. The materials for the study were adopted from the body measurement data of women in the age group of 30 to 39 years old, provided from Size Korea. By reflecting the factor analysis results using the three-dimensional shape measurement, deviations were derived. First, six factors influencing the changes in human body shape were derived as waist-hip length factor, bust-waist shape factor, back protrusion back shoulder factor, bust length factor, shoulder length factor, and frontal waist dart factor. The bust size and height, which can be easily utilized for the top original grading, were used for deriving a regression formula, and the deviation was set in accordance with the result. Second, by applying the deviation which reflects the changes in the body shape, the crimps which were generated due to the application of existing deviation were remarkably reduced, indicating that the grading of the present study is more fitting than the existing one. The deviation derived by the analysis of actual increase and decrease of body size was more fitting than the existing one. This was proved by actual wearing experiment, which represents the significance of this study.

• Journal of the Korean Society of Costume
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• v.56 no.7 s.106
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• pp.121-132
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• 2006

The feeling of self-confidence, the sense of well-being and of social acceptance that comes from the wearing clothes that is functional, appropriate, and attractive, is important to all the people, but to those with physical limitations, it is much more important. Finding well-fitting clothing can be a big challenge for them. This study focus on the cut of present available ready-to-wear garments and commercial patterns giving better fit and greater comfort and satisfaction. Subjects were limited to the people with body deformities caused by the brain injury. This can also meet the needs of silver groups in the aging society under the terms of human values and human rights. This study is based on the questionaires and interviews to identify the problems of ready-to-wear or commercial patterns, purchasing behaviors, and the demand for the functional clothes. This study focused on following objectives; 1) to discover what the problems are which confront the people with body deformity, 2) to find the problems in ready-to-wear garments or commercial patterns, 3) to provide information of pattern alteration f3r people with body deformities. A major limitation to the study is that the subjects numbers are limited and the distribution is not even. For the future study, large database with wide varieties of age and fitting test are suggested.