• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.25-33
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• 2006

The purpose of this study is to develop the curve fitted equations for practicality and actual calculation during seismic performance evaluation of buried pipelines. Curve fitting for strain curve according to the wavelength of the seismic wave was produced using the non-linear least square method and the equations with the best results was suggested. In addition, a degree and coefficient of polynomial fitting equation needed to use curve fitted equation were identified. Interpreting process during the test of resistance of earthquake of buried pipelines with various end boundary conditions were provided through example questions. The results of this study were used to conduct a dynamic response analysis and a seismic performance evaluation of concrete, steel, and FRP pipes with various end boundary conditions.

• The Korean Journal of Applied Statistics
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• v.29 no.7
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• pp.1155-1163
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• 2016

This paper deals with an estimation procedure of variance components in a mixed effects model by projections. Projections are used to obtain sums of squares instead of using reductions in sums of squares due to fitting both the assumed model and sub-models in the fitting constants method. A projection matrix can be obtained for the residual model at each step by a stepwise procedure to test the hypotheses. A weighted least squares method is used for the estimation of fixed effects. Satterthwaite's approximation is done for the confidence intervals for variance components.

• Journal of Ocean Engineering and Technology
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• v.25 no.1
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• pp.67-72
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• 2011

Offshore structures, such as a platform, a buoy, or a floating vessel, are exposed to several dynamic loads, and viscoelastic damping material is used to reduce the vibration of offshore structures. It is important to know the properties of viscoelastic materials because loss factor and Young's modulus of the viscoelastic damping material are dependent on frequency and temperature. In this study, an advanced technique for obtaining accurate loss factor and Young's modulus of the viscoelastic damping material is introduced based on a multi degree of freedom curve-fitting method and the RKU (Ross-Kerwin-Ungar) equations. The technique is based on a modified experimental procedure from ASTM E 756-04. Loss factor and Young's modulus of the viscoelastic damping material are measured for different temperatures by performing the test in a temperature-controlled vibration measurement room where temperature varies from 5 to 45 degrees Celsius.

• Journal of the Korean Society of Costume
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• v.59 no.1
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• pp.94-105
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• 2009

Jeogori, Korean jacket, can be categorized into two styles. Traditional style Jeogori is based on conventional construction method for ceremonial or festive occasions. Contemporary casual style Jeogori is based on western style flat pattern making for better fitting and functionality. Traditional style Jeogori is quite flat on human body because it is not considered the grade of shoulder line and is drawn by vertical & horizontal line. This characteristic feature causes weakness in functionality and comfort compared to contemporary casual style. Apparently contemporary casual style has better wearing comfort. Yet to most Koreans, contemporary style Jeogori seems to lack of some characteristic style of its own. This study is to find out how to make Jeogori well balanced in terms of functionality, fit, comfort and traditional style. Currently used Jeogori patterns are compared in order to select the best among them. Onto the selected pattern, several alterations were tried focused on shoulder, armhole and sleeve lines to make optimal modifications. After several comparative fitting tests, the final pattern making method was suggested.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.11
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• pp.632-638
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• 2003

Modern power systems are very complex and to model them completely is impractical for electromagnetic transient studies. Therefore areas outside the immediate area of interest must be represented by some form of frequency dependent equivalent. The s-domain rational function form of frequency dependent equivalent does not need refitting if the simulation time-step is changed in the electromagnetic transient program. This is because the s-domain rational function coefficients are independent of the simulation time-step, unlike the z-domain rational function coefficients. S-domain rational function fitting techniques for representing frequency dependent equivalents have been developed using Least Squares Fitting(LSF). However it does not suffer the implementation error that exited in this work as it ignored the instantaneous term. This paper Presents the formulation for developing 1 Port Frequency Dependent Network Equivalent(FDNE) with the instantaneous term in S-domain and illustrates its use. This 1 port FDNE have been applied to the CIGRE Benchmark Rectifier test AC system. The electromagnetic transient package PSCAD/EMTDC is used to assess the transient response of the 1 port (FDNE) developed with Thevenin and Norton Equivalent network. The study results have indicated the robustness and accuracy of 1 port FDNE for electromagnetic transient studies.

• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.260-265
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• 2022

In this study, we establish hyper-elastic haptic feedback in a virtual environment using finite element analysis techniques and develop a Force Torque (FT) sensor utilization method for application in tele-operation environments. In general, regarding haptic feedback data, in a tele-operation environment, the user is provided with feedback according to the measured force data when the model is inserted through an FT sensor. Conversely, in a virtual environment, the press-fitting model can be expressed through the spring-damper system rather than an FT sensor to provide feedback. However, unlike rigid and the elastic bodies, the hyper-elastic body represented by a spring-damper system in a virtual environment is a simple impedance model using stiffness and damping coefficients; it is limited in terms of providing actual feedback. Thus, in this study, haptic feedback was implemented using the data obtained from POD-RBF analysis results during hyper-elastic press-fitting experiments. The haptic feedback mechanism developed in this study was verified by comparing the FT sensor feedback data measured and calculated through hyper-elastic press-fitting experiments with spring-damper feedback data. Subsequently, the POD-RBF analysis feedback was compared and evaluated against the feedback mechanism of each environment through the test subject, and the similarities between the POD-RBF analysis feedback and FT sensor data feedback were verified.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.3
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• pp.245-252
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• 2016

In this study, an alternative bend design is proposed to overcome the aging problem in piping bends. In this design, the foam pad is not included. Finite element analysis was performed based on the total pipe diameter. From this analysis, the shape of the Shear Control Ring (SCR) was determined. Temperature, stress, and other data of the proposed reinforced pipe were acquired and analyzed after the test was performed. The value of the thermal stress for the reinforced steel pipe satisfied the required standard without the foam pad based on the manufacturing of the reinforced fitting and construction site of the test. The reinforcement provided a shear strength level for the foam pad that resulted in maximum shear stress less than stress based on the original foam pad applied at the pipe bend. Additionally, an increasing factor of safety effect for the reinforced fitting application was discovered.

• The Research Journal of the Costume Culture
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• v.31 no.5
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• pp.640-650
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• 2023

This study aimed to suggest a suitable collar pattern by visually evaluating the appearance of the amount of collar drape by the starting position of the lapel line of a double-breasted tailored jacket using a 3d virtual fitting program. It created an avatar based on the mean size of women in their 20s (the 8th Size Korea) using clo network (double fastening: 10cm, collar width: 4.5cm, collar stand: 3cm, and lapel width: 8.5cm). The starting of the lapel twist line was waistline level, the 1/2 level of bustline and waistline, or bustline level, and collar laying amount was 4.5, 5.5, 6.5, or 7.5cm. It was evaluated by garment construction experts using 5, 6, and 4 items on the front, sides, and back, respectively. Descriptive statistics, F-test, Duncan-test, and reliability analysis were conducted using SPSS 22. When collar laying amount was 6.5cm, it was best rated regardless of the starting point. Under waist line, when collar laying amount was 6.5cm, it was best rated regardless of the starting point. When collar laying amount was large, the collar's outline length increased, resulting in unnecessary wrinkles from the neckline to the lapel, affecting the overall collar appearance. When collar laying amount was the smallest, the collar was lifted and the width was narrowed, exposing the seam connecting the collar and neckline. The length of the collar's outline varied depending on collar laying amount, which was important to make the outline sit comfortably on the body.

• Journal of the Korean Society of Costume
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• v.66 no.8
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• pp.46-60
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• 2016

Countries have different brassiere patterns, and this study produced and compared 3/4 brassiere patterns from different countries to determine the difference in patterns, and to investigate the stress distribution and shape of cross section while wearing brassieres using 3D virtual fitting system. Despite the growing interest in underwear, there is a lack of related books and research on brassiere patterns, which causes the difference in sizes and pattern drafting methods by countries. Thus, research on this is needed. 3D virtual fitting system has been introduced to compare patterns, thereby improving visible effects and reducing the loss in cost caused by underwear pattern fitting test. According to the result of pattern analysis, The Secoli type exhibited the least breast cover rate (14.9 cm), while the largest cover rate was shown in Christina and ESMOD types (17.7 cm). It is believed that the difference in pattern drafting causes the difference in the total length of a brassiere. Furthermore, the Secoli, Moda Burgo, and ESMOD brassieres drafted from basic bodice pattern were found to be longer than the Christina and Han Sunmi brassieres attained from direct pattern drafting. Moreover, the darts' volume of upper and lower cups in Christina and Han Sunmi types was similar in shape. The shapes of cradle drafted from basic bodice pattern were a straight line, while those from direct drafting formed a curved shape. In fitting multiple cross sections, the Secoli, Moda Burgo, and ESMOD brassieres had gaps between the brassieres and the body. Among these, the largest number of gaps was observed in the ESMOD type pattern. This study aimed at performing comparative analysis of various brassieres' pattern drafting types as a basic research for developing a brassiere pattern drafting type.

• Journal of the Korean Society of Costume
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• v.58 no.1
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• pp.133-150
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• 2008

The purpose of this study was to recognize of the sizing system and analyze the fitting on formal pants of the on-line shopping mall for plus-sized women. To pursue this purpose, the investigation of the sizing system was focused on 22 online companies. The formal pants of 7 companies was selected among them. And actual sizes were compared with the guidance sizes of goods. For the assessment about the fitting on formal pants of 7 online companies, these came to make on to 16 obese women with 'A' body shaped and 'O' body shaped. A data analysis used the SPSS 14.0 statistics program. To verify the difference, this study used the variance analysis and Duncan's test for the postmortem verification. The result was as follows. 1. All of 22 companies were using the symbol such as 88, 99, 100 and 110 in the present condition of sizing system. The information about products size was presenting the products size not to be the body size. the guidance sizes of products were different from actual sizes of 7 companies to be assorted. Therefore, the guidance sizes of goods could not accomplish the facility. 2. According to the fitting-tests by the sensory assessment, the obese women with 'A' body shaped, did the dissatisfaction at the items of the hip circumference, abdominal region, crotch deep and pants length. The obese women with 'O' body shaped, did the dissatisfaction at the the items of crotch deep and pants length.