• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.145-155
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• 1998

An $H{\infty}$ controller with a roll eccentricity filter is proposed to alleviate the effect of entry thickness variation and roll eccentricity occured in rolling stands themselves of tandem cold mills. A robust controller to the disturbances is designed by H$_{\infty}$ control techniques, which can reflect the input direction of disturbances and the knowledge of disturbance spectrum in the frequency domain. First, fundamental problems in tandem cold mills such as process transport delay inherent in the exit thickness measurement and the feedforward loading of roll eccentricity signals on the exit thickness be overcome by the roll eccentricity filtering and the compensation for the error of gaugemeter thickness estimator. And non-satndard $H{\infty}$ control problem caused by the selection of weighting function having poles on the $J{\omega}$-axis is discussed. The resultant controller composed by an $H{\infty}$ controller and an estimator for the roll eccentricity is evaluated through computer simulations. The effectiveness of the proposed control method is compared to that of the conventional LQ controller method and a feedforward controller for the roll eccentricity, which has been already studied.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.10
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• pp.999-1006
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• 2004

Recently, the ride comfort problem becomes increasingly important because of today's needs for train speedup. The railway has the track irregularities which cause vibrations, such as rail joints, turnout, level crossing, transition corves and super-elevation ramps, and variations in the track level(z-axis) and the gauge(y-axis). In Korea, the service run of the high speed train has been made since the 1st of April, 2004. The commercial high-speed trains must be run on the compound lines which are composed of high-speed line and conventional line. The high speed lines in both Kyoungbu line and Honam line have 57.5％ and 33.8％, respectively In this Paper, the ride comfort has been reviewed by the various experimental methods when the high-speed trains are operated on both Kyoungbu line and Honam line. The results show that the high-speed train has no problems from the viewpoint of the comfort ride during the operation on the high speed line and conventional line.

• The Korean Journal of Health Service Management
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• v.7 no.4
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• pp.13-22
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• 2013

The purpose of this study was to identify the influencing types of stress and coping method among College and University students. The design for this study was descriptive using self-administered questionnaires. The data was collected from 1 July to 30 July 2012. 284 students in College and University located in Gyeongsangbuk-do. This data were analyzed by SAS 9.2 program using descriptive statistics, frequency, T-test, ANOVA, and Correlation analysis. The results were as follows. First, there was a difference between male and female in the level of stress, it was statistically significant(p<0.0001). Second, there was a remarkable difference in the level of stress between University and College students(p=0.0001). Third, in the evaluation of correlation, relation between study factor and career factor was statistically significant(0.59, p<0.001). However there was no positive correlation between the five stress-induced factors and problem-based handling way of stress. On the other hand, there was strong positive correlation between the five stress-induced factors and emotional-based coping method of stress(p<0.01).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.2
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• pp.148-156
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• 2008

In this study it will be discussed how to solve the problem of discomfort from rolling motion on the fishing boats. Most discomfort is caused by the short cycle of rolling due to the light weight of the boats. The light weight is due to the FRP material which dries a boat. A way to improve the feeling of boarding by using fish hold was researched. The experiment was done on experimental fishing boat made by FRP in Jeju. An existing fish hold was designed and manufactured through the rolling test and that was used for a marine experiment. The rolling condition of the U-tank boat ideally designed was compared to that of an existing fishing boat using the same conditions. The experiments were carried out two times on the stop engine in the outward Sehwa fishing port, which the experimental data had analysed for effects of rolling reduction to compare the U - tank with the of exiting fish hold. The results were confirmed that the U-boat tank in the roll period and GoM were more safe than the existing fish hold and the average amplitude and significant of rolling angles were decreased relatively.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.3
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• pp.47-55
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• 2010

Investigations on the inundation damage and improvement measures were carried out centering around the protected horticultural complex concentrated in lowlands on the side of Geum river, in Nonsan and Buyeo, Chungnam. Most greenhouses were single-span plastic houses in this area, and tomato, strawberry and watermelon were cultivated mainly. 45.8 % of whole farmhouse were experienced in damage by inundation, and a frequency of the damage was average once in 11 years. The most urgent problem at the greenhouse culture in this area was showed in order of drainage improvement, irrigation water resources and energy saving. Consideration items in drainage improvement project for protected horticulture were showed in order of extending drain pumps, extending drain canals, using concrete flume in drain ditch. It needs to consider systematic plans that can restrain new establishment of greenhouses on the lowland paddy field in drainage area. It is difficult to remove greenhouses which are already established or prohibit cultivation. Therefore we should impose minimum duty items so that greenhouse tillers can cope with inundation. And it is thought that managing agency need to minimize farmers damage by improving drainage ability and introducing maintenance pattern that is different from rice cropping.

• Fashion & Textile Research Journal
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• v.19 no.1
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• pp.30-39
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• 2017

This study examines on the relationship of appearance instrumentality and appearance-related variables (appearance concern, appearance management behavior) of college students. Questionnaires were administered to 313 college students living in Daegu. The SPSS 20.0 package was utilized for data analysis which included frequency analysis, Cronbach's ${\alpha}$, factor analysis, cluster analysis, cross tabulation analysis and t-test. Three factors of appearance instrumentality(love relationship, social achievement, interpersonal relationship), two groups of appearance concern(high, low) and five factors of appearance management behavior(skin care/cosmetics usage behavior, body management behavior, plastic surgery behavior, hair management behavior, fashion management behavior) were utilized for the problem analysis of the study. The results of this study were: First, there was no significant differences in the appearance concern group according to appearance instrumentality. Second, appearance instrumentality had a significant differences on appearance management behavior. Social achievement showed a significant differences in plastic surgery behavior. And love relationship showed a significant differences on plastic surgery behavior and fashion management behavior. Third, the appearance concern had a significant differences on all of appearance management behavior. High group of appearance concern showed a higher average than low group of appearance concern in fashion management behavior, skin care/cosmetics usage behavior, hair management behavior, plastic surgery behavior, body management behavior.

• Agricultural and Biosystems Engineering
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• v.5 no.2
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• pp.40-44
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• 2004

This study was conducted to solve the problem of spinach harvesting done by manpower at the outdoor field during the cold winter season. Prototype spinach harvester was designed to dig, pick-up, and collect in a continuous operation for harvesting outdoor field-planted crawling type spinach. In the field test, two types of blades (Type A : angle of $150^{\circ}$, Type B : straight) were used for measuring the cutting loads of spinach and chain conveyor with lugs was used for picking up the root cut spinach. Prototype's vibrating blade reduced the digging power of the fixed blade by $46\%$. The loss was also very little ($0.7\%$) with a digging depth of 4 cm, an oscillation frequency of 748 rpm, and an oscillation distance of 33 mm. The working performance of the prototype spinach harvester was 38 hour/ha resulting to $96\%$ labor cost reduction compared to the conventional harvesting.

• Journal of the Korea Safety Management & Science
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• v.15 no.2
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• pp.223-232
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• 2013

Other comments on matters satisfaction survey through questionnaires typically measure by frequency analysis method is performed, the short answer for how to apply. These satisfaction surveys, however, because of the environment and atmosphere of its target at the time of the survey, personal psychological state, depending on the scale of change in business or policy of customer satisfaction feedback, there is a problem. This survey results, tangible results in terms of the feasibility of the business and policy indirectly as a result, which has been used as a material fact is. New survey method is show how the business and policy objectives than can be reflected positively in the present study, and comparing these surveys in a variety of ways for the analytical method proposed by KANO, Timko results suggested. Should be an ongoing investigation, and different survey methods for the study on the same sample the actual observed by comparing the results for the superiority of the new results presented.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.280.2-286
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• 1998

Flood is the main natural disaster mostly in the world. It is a care problem to prevent flood disaster generally. The frequency of flood disaster is high and the distributing field is wide, the 50 percent population and 70 percent properties distribute at the threaten field of flood disaster in China. Flood disaster has caused a huge amount of economical losses and these losses have an increasing trend. Along with the development of reducing natural disaster action, it has become one of the most attentive problems for monitoring flood, preventing flood and forecasting flood efficiently. Remote sensing has the characteristics of large spatial observing areas, wide spectrum ranges, and imaging far away from the targets, imaging capabilities all weather. Spatial remote sensing information, which records the full, processes of the disaster's occurrence and development in real-time. It is a scientific basis for management, planning and decision-making. Through systemic analyzing the RS monitoring theory, based on compounding RS information, the technology and method of monitoring flood disaster are studied.

• Tribology and Lubricants
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• v.18 no.5
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• pp.351-356
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• 2002

The surfaces of machine components in sliding contact such as bearing, gears and pistons etc. frequently operate under the condition of mixed lubrication due to high load, high speed and slip. These machine components often undergo the inception of scuffing in practical application. The scuffing failure is a critical problem in modern machine components, especially for the requirement of high efficiency and small size. However, it is difficult to find a universal mechanism to explain all scuffing phenomena because there are so many factors affecting the onset of scuffing. In this study, scuffing experiments are conducted using Acoustic Emission(AE) measurement by an indirect sensing approach to detect scuffing failure. Acoustic Emission(AE) signal has been widely utilized to monitor the interaction at the friction interface. Using AE signals we can get an indication about the state of the friction processes, about the quality of solid and liquid layers on the contacting surfaces in real time. The FFT(Fast Fourier Transform) analyses of the AE signal are sued to understand the interfacial interaction and the relationship between the AE signal and the state of contact is presented.