• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1483-1490
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• 2011

Electro-hydrostatic actuators(EHAs), which are usually composed of a direct motor-driven hydraulic pump and a cylinder, have been widely adopted as aircraft actuation systems because of their benefits in terms of improved efficiency, weight savings and the fact that they use a standalone power source. Since the recent trend in construction vehicles has been focus on energy savings in their hydraulic systems, EHAs are expected to be potential substitutes for conventional power transmission, since they are capable of energy recovery as well as highly efficient pump control. In this paper, the start and stop characteristics of EHAs were investigated through cracking pressure analysis of the pilot-operated check valve(PCV), which enables the cylinder to standstill against an external load with no holding effort from the hydraulic pump. A mathematical model that includes the load dynamics and the EHA's internal hydraulic circuit was derived for simulation with the MATLAB Simulink package. This model verified the PCV's opening and closing sequence, which in turn affects the EHA's start and stop characteristics.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.1 s.106
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• pp.40-49
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• 2006

A novel disturbance measurement method, model based disturbance observer (MBDO) for optical disk drives (ODDs), is proposed and the disturbance analysis using the proposed method is performed under various conditions. In ODDs, the quantitative and qualitative analysis for the generated disturbance during normal operation is very important to successful servo loop design. However, the disturbance measurement is difficult, and high precision measurement is necessary. Furthermore, the conventional disturbance measurement method using a LDV (laser Doppler vibrometer) has many difficulties in eccentricity direction due to the vertical movement of an optical disk. To solve this problem, the MBDO is proposed. First, the relationship between the servo loop for ODDs and the generated disturbance are briefly reviewed. Second, the principle of the MBDO is introduced, and the disturbance measurement results, which are measured by the MBDO and a LDV, are compared. In these experiments, test DVD-ROM disks are used to generate quantitative/qualitative disturbance. Then, the disturbance analysis under various conditions is performed using waterfall technique. This technique clearly shows the disturbance trend from the inner part of an optical disk to the outer part of it. Finally, the various disturbances measurement results are summarized and some remarks for it are commented.

• Structural Engineering and Mechanics
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• v.75 no.5
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• pp.571-583
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• 2020

Permeation grouting is of great significance for consolidating geo-materials without disturbing the original geo-structure. To dip into the filtration-induced pressure increment that dominates the grout penetration in permeation grouting, nonlinear filtration coefficients embedded in a convection-filtration model were proposed, in which the volume of cement particles in grout and the deposited particles of skeleton were considered. An experiment was designed to determine the filtration coefficients and verify the model. The filtration coefficients deduced from experimental data were used in simulation, and the modelling results matched well with the experimental ones. The pressure drop revealed in experiments and captured in modelling demonstrated that the surge of inflow pressure lagged behind the stoppage of flow channels. In addition, both the consideration of the particles loss in liquid grout and the number of filtrated particles on pore walls presented an ideal trend in filtration rate, in which the filtration rate first rose rapidly and then reached to a steady plateau. Finally, this observed pressure drop was extended to the grouting design which alters the water to cement (W/C) ratio so as to alleviate the filtration effect. This study offers a novel insight into the filtration behaviour and has a practical meaning to extend penetration distance.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.12
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• pp.1247-1256
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• 2012

The paper details the development of a Korean style loungewear based on traditional Korean hanbok clothing. For this, we surveyed and collected data from 3,500 adults over 20 years of age. The questions were on their preferences of hanbok for both traditional and contemporary styles as well as loungewear. The survey showed that preferences for hanbok were high for both traditional and contemporary styles. The survey also suggests how a successful mass-produced Korean style loungewear should be designed to increase its popularity. It should feature comfortably simplified silhouettes, a selection of contemporary colors from Korean symbolic colors, modernized Korean textile surface designs, and easy-to-maintain healthy fabric. Based on these results, the development direction of Korean style loungewear was set and various loungewear samples were produced. Another group of survey participants were asked to try on samples and their preferences were surveyed. At the conclusion, a version that was most preferred among the participants was obtained. We suggest one-piece style and two-piece style designs with silhouettes based on the characteristics of traditional Korean costumes. The preferred fabric for loungewear was natural and soft cotton. We suggest the necessity and effectiveness of loungewear made with environment-friendly hanji-fabric. The main colors for loungewear were selected based on survey: blue, red, white, and saekdong (color stripes). We made color combinations with the main colors then applied the textile surface designs. The traditional Korean patterns of Hangeul (Korean letters), taegeuk (yin-yang), geometric figures, and samjogo (three-legged crow) were also chosen, and then loungewear using the textile designs was developed. The results have been shown on the "Han Style Fashion Show" by Jeonju City and exhibited in the "Seoul Living Design Fair" and the "International Art & Craft Trend Fair" in COEX, Seoul.

• Journal of Animal Environmental Science
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• v.6 no.1
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• pp.1-14
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• 2000

The structural and environmental characteristics of typical pig houses in different growth phases were surveyed and analyzed. Based on the data for thirty nine selected farms in four provinces, Jeonbuk-do, Jeonnam-do, Gyeongbuk-do, and Gyeongnam-do, in the southern provinces, Korea, the goal is to eventually establish standard pig houses of sow and litter, nursery pigs, and growing-finishing pigs. The survey included farm scale, production specialization, structural dimensions of the houses and their ventilation systems, cooling and heating systems, and floor and pit systems related to manure collection. The survey showed 90∼98% of growing-finishing pig houses adopted the sidewall curtain systems. The sidewall curtain systems, although popular, is not well insulated which leads to excessive heating costs in winter. Regarding flooring and manure collection system of the house, 23∼35% of growing-finishing houses installed scraper systems with concrete-slat floors in Gyeongsang provinces while 52∼78% did in Jeolla provinces. The cause of a large variance in flooring between tow regions could not be academically pinpointed, rather it could be attributed to the advice of neighbors who leads local pig production circle. A general trend toward enlargement and enclosure of pig houses for all growth phases was gaining popularity in most regions in recent years. A steady shift to multisite operation from continuous operation was also observed to prevent a disease transfer. The structural design of a standard pig house with its environmental control systems including ventilation and heating/cooling system was suggested for further validation study. In-depth analysis of the survey data is presented in the Results and Discussion section.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.1
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• pp.32-39
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• 2011

When the laws about the security of ships are revised, or voyage conditions are changed, ship owners have converted rather than built new passenger ships including cruise ships recently. As conversion causes a lot of changes in principal dimension, structural strength, hydrodynamic performance, the number of passengers, and cargo capacity, detailed pre-review is needed. But any studies on conversion have not been carried out yet, this study investigated and analyzed the trend of consulting companies' reports (Delta Marine Report, 2005, 2008). As a result, it was found that lengthening conversion brought about the main changes in principal dimension, and performance. Also it was suggested that there be factors for consideration like hull scantling, hull form, and cutting point to minimize side effects when ship owners build ships having lengthening conversion in mind.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.5 s.153
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• pp.788-799
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• 2006

The purpose of this study was to analyze fashion merchandising process, to apply customer information in merchandising process and to examine customer management strategies of fashion industry in on-line and off-line channel. In depth, face to face interviews with structured questionnaires were conducted with MD and customer managers from selected 4 brands, one from each categories of men's, women's, casual and sports wear. Key findings of the study were as follows: First, they followed fashion merchandising process of 18 steps and collected trend information and sales data were applied to planning, selling/promoting process to plan season concept, design, and promotion activity. Second, commonly applied customer information types in fashion merchandising process were all from indirect information collected from sales data and forecasting companies. However, casual and sports wear conducted consumer monitoring activity f3r collecting customer data directly from customer participation. Third, in off-line channel, customers are segmented by amount of purchase they make in a specific time period and all the categories show high interest in valuable customers. However, only men's and woman's wear conducted promotion activities for valuable customers as a differentiated marketing strategy. In on-line channel, companies were interacting with the customers through internet web site to determine their demands. In conclusion, this study has significance in that it propose the necessity and strategy of differentiated customer management approaching by analyzing and comparing fashion merchandising activity process cases.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.8
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• pp.1275-1287
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• 2006

This was to confirm the Web-SFAS and street Fashion trend 2005. Korea women's street fashion in 2005 S/S was analyzed by using the Web-SFAS(Street Fashion Analysis System) that was developed and completed in the earlier research. Total 270 women who were sensitive to the fashion were surveyed around in 5 nationwide cities and 9 commercial zones. The analysis results of the questionnaire and image survey in 2005 S/S for each commercial zone is shown as follows: 1. The sequence of care with most interest in producing fashionable shape is in the order of clothes>accessory>hair style>make up>shoes, and it was found that the proper reason for visiting the commercial zone is to meet with friends than shopping. 2. Most preferred item for tops were shirts and T-shirts, while for bottoms were blue jeans of denim material in various colors and designs. The color had the clear winner in white color with the pink or yellow line of colors preferred in all commercial zones. The blue jeans and skirt items were the most dominant with the preference on the blue color. The color and image were diversely favored with light, natural, modern, elegance and warm images. 3. The semi-formal image was preferred in women's street fashion, 2005 S/S in Apgujeong-dong, Hapseong-dong, Myeong-dong, Hongik University area, Dongseong-ro, and the active comfort casual image was preferred by womens in Seo-myeon, Nampo-dong and Sangnam-dong. However the retro image were represented in Daehak-ro specially. The tendency of street fashion for women had the difference of their own trends for each commercial zone, rather then the regional differences for each city with the conspicuous preference of color for the items.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.1
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• pp.92-103
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• 2009

The study is interested in the consumer's mixed choice of the internet and the offline stores. Therefore the purpose of study is to investigate if the clothing shopping orientation of consumers varies when they shop internet and offline, instead of classifying consumers into internet shoppers and offline shoppers. For the purpose, quantitative survey was carried out using 201 questionnaires from men and women in their twenties. The data were analyzed using factor analysis, Pearson's correlation analysis, Spearman's rank order correlation coefficient, t-test, and frequency analysis. The results are as following. First, the clothing shopping orientation structures of offline and internet stores were different each other. As the result of factor analysis, positive, brand oriented, economic, convenient conformity, convenient impulsive factors were extracted from offline store and rational, enjoying, goal oriented, conformity, brand oriented, convenient impulsive purchase factors were extracted from internet store respectively. Second, as the results of investigating the relationship between the clothing shopping orientation structures of offline and internet stores, positive(off)-enjoying(on), brand oriented(off)-brand oriented(on), convenient conformity(off)-conformity(on) had strong correlation s and the rest were peculiar to the each store type. Specifically, the goal oriented factor peculiar to the internet store was noticeable. Third, as the results of investigating the differences between clothing shopping orientation of offline and internet stores, the ranks of strong orientation dimension were different between two channels. As well, the mean differences were significant in goal oriented, conformity, brand oriented, and convenient impulsive purchase dimensions. This study has the significance that it investigated the variance of clothing shopping orientation according to the mixed selection trend of internet/offline.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.8
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• pp.1202-1210
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• 2007

The purpose of this study was to identify factors of shopping orientation and factors of preferred stores for female shoppers aged from 45 to 64. Also women's markets for these ages were segmented based on their shopping orientation, and consumer groups were compared in terms of demographics and preferred store characteristics. Data from 238 women aged between 45-64 were collected by survey method and used for statistical analyses. Factor analysis, cluster analysis, $X^2$ test, F test, Duncan test were done. The results were as follows. First, five shopping orientation factors, such as high involvement, fashion orientation, brand orientation, other people orientation, and economic orientation were found. Second, five factors of preferred store characteristics were identified. They were store environment, product characteristics, trend and brand, accessibility, and sales personnel factors. Four consumer groups of brand pursuing, fashion pursuing, other-dependent, and high-involvement were classified. Those consumer groups showed significant differences in terms of demographics and preferred store characteristics. In conclusion, Korean women aged 45-64 were shown to have some differences in their shopping orientation compared with young women and to differ in preferred store factors among their groups.