• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.1
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• pp.114-130
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• 2016

This research provides practical data to develop UV protection masks and dust protection masks. It surveyed uncomfortable factors and significant characteristics for masks. It used 653 subjects 20-79 years old and performed the research from April to May in 2014. Wearing masks at outdoor activities is not widely popular yet, but golf players, mountaineers and old people were quite interested in masks. People mainly wore a basic shape mask, but main age group of each mask shape was different. People usually prioritized the protection function and comfort of wearing over design; however, women, young generation and people attending to outdoor activities longer than 1 hour considered design quite important. People going on picnic or camping consider mask characteristics most important. Therefore, various mask shapes and protective functions should be developed to reflect consumer needs. Meanwhile, the discomfort levels of masks were not too high, but old people felt more discomfort than young people. The most discomfort factors were 'other's eye', 'distracting face movement' and 'feeling of foreign object'. They also mentioned falling problem of C shape mask and short-rib shape mask, and asked for a 'tighter fit' at the ear.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.501-507
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• 2010

In this study, we evaluate the anti-microbiological activity of paraben in eye shadows that are composed of pigments and oil binders using various analytical methods and microbiological tests. Paraben does not show the microbiological activity properly when it was used with Nylon SP$^{(R)}$ 10, Talc RF SSA$^{(R)}$, OMC Talc AS$^{(R)}$ and $BaSO_4$. In the test of fungi, Nylon SP$^{(R)}$ 10 causes the decrease of microbiological activity regardless of the type of oil binders. The pigment of Mango violet also causes the decrease of microbiological activity when ester oil binder was used. Regardless of the type of oil binder, samples containing nylon SP 10, 0.15% of methyl paraben and 0.05% of propyl paraben had not been able to maintain microbiological activity only if the concentration of parabens were increased. Trace amounts of metal ions present in pigments reduced the activity of preservatives by inactivation of hydroxyl group of paraben. It is thought that swollen nylon SP 10 in ester oil increase the absorption or interaction of parabens and swollen nylon powder causes the inactivation of paraben.

• Transactions on Electrical and Electronic Materials
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• v.8 no.4
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• pp.166-169
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• 2007

In applying LCD to TV application, one of the most significant factors to be improved is image sticking on the moving picture. LCD is different from CRT in the sense that it's continuous passive device, which holds images in entire frame period, while impulse type device generate image in very short time. To reduce image sticking problem related to hold type display mode, we made an experiment to drive TN-LCD like CRT. We made articulate images by turn on-off backlight, and we realized the ratio of Back Light on-off time by counting between on time and off time for video signal input during 1 frame (16.7 ms). Conventional CCFL (cold cathode fluorescent lamp) cannot follow fast on-off speed, so we evaluated new fluorescent substances of light source to improve residual light characteristic of CCFL. We realized articulate image generation similar to CRT by CCFL blinking drive and TN-LCD overdriving. As a result, reduced image sticking phenomenon was validated by naked eye and response time measurement.

• 전자공학회논문지 IE
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• v.48 no.1
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• pp.16-24
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• 2011

In this paper, we developed a auto sorting system for T type welding nut using a vision inspector. We used edge and thread detection with histogram of image which is captured by machine vision camera. We also used a binary morphology operation for a detection of spot. As a result we performed numeric inspection of 0.1mm accuracy. This is impossible in old sorting system and inspector with naked eye. Also, we reduced the manufacturing unit cost to 25% and improved a production efficiency to 330%.

• Journal of the Korea Safety Management & Science
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• v.24 no.1
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• pp.91-98
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• 2022

Since cranes are a kind of complex human-machine systems, it is almost impossible to completely secure safety with current technologies. Therefore, managerial interventions to prevent human errors are needed for safely operating a crane. The Occupational Safety and Health law states that cabin-type crane operators should have crane drivers' licence and crane-related operators (e.g., pendent-type crane operators, slinging workers) should take a special safety training. However, statistics on industrial accidents showed that fatalities due to crane accidents (185 accidents occurred during 2013~2017) were the highest among hazardous machinery and equipment. To effectively control the crane-related accidents, voices of crane workers need to be analyzed to investigate the current status. This study surveyed perceived causes of crane accidents and status of special safety training for crane workers of 387. The survey revealed that 24.3% of the respondents experienced crane accidents and 31.4% eye-witnessed crane accidents. 79% of the respondents pointed human errors such as improper crane operation and improper slinging as the first cause. Lastly, only 16.7% of the respondents took a professional special safety training; but the rest took lecture-based or incomplete education. The findings of the present study can be applied to improve crane-related policies and special safety training systems.

• Journal of the Korean Society of Food Culture
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• v.21 no.3
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• pp.344-350
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• 2006

The study aims to examine whether regular leisure activity of the elderly with active and passive types has a beneficial effect to enhance their health condition. The elderly subjects of 164 (82 of elderly who do active leisure and 82 of elderly who do passive leisure) aged over 60 years in Suwon area were employed. Survey questionnaires were administered to investigate general characteristics, life style, and health status along with anthropometric measurement. From the findings, the elderly who do active leisure were highly educated and better in living status. The elderly who do passive leisure showed higher drinking and smoking rates as well as higher obesity and overweight rates in comparison to the other counterpart. Furthermore, the elderly who do passive leisure were poor in health status. 'Painful knee and eye', 'lower back pain', and 'fatigue' were the most prevalent among subjective symptoms of the elderly. In conclusion, the elderly with active leisure activity seemed to have better life style and maintain good health status. Therefore, it is critically important to establish the health program combined with various leisure activity for the seniors to promote and energize the later years of life.

• Journal of IKEEE
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• v.13 no.4
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• pp.70-74
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• 2009

In this paper, We propose the visible light communication(VLC) link based on white light emitting diode (LED) and Photo detector(PD). The proposed architecture is demonstrated experimentally and its performance is verified through the experimental results of quality-factor(Q-factor) and eye pattern of 10Mb/s PRBS signal. The ambient light effect from a typical type fluorescent lamp source was also analyzed. when the distance between the LED and the PD is about 1m, error free wireless transmission of the LED was achieved up to 10Mb/s data rate. Under the condition with ambient light, low BER, data transmission of the VLC link is achieved up to 5Mb/s data rate at 1m. Also, when the PD is placed away from the center, low BER data transmission of the VLC link is achieved up to 1Mb/s at 10cm and 10Mb/s at 5cm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.10
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• pp.1012-1015
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• 2011

The decision-directed blind equalization algorithm is often used due to its simplicity and good convergence property when the eye pattern is open. However, in a channel where the eye pattern is closed, the decision-directed algorithm is not guaranteed to converge. Hence, a modified Bussgang-type algorithm using a hyperbolic tangent function for zero-memory nonlinear(ZNL) function has been proposed and applied to avoid this problem by Filho et al. But application of this algorithm includes the calculation of hyperbolic tangent function and its derivative or a look-up table which may need a large amount of memory due to channel variations. To reduce the computational and/or hardware complexity of Filho's algorithm, in this paper, an improved method for the decision-directed algorithm is proposed. In the proposed scheme, the ZNL function and its derivative are respectively set to be the original signum function and a narrow rectangular pulse which is an approximation of Dirac delta function. It is shown that the proposed scheme, when it is combined with decision-directed algorithm, reduces the computational complexity drastically while it retains the convergence and steady-state performance of the Filho's algorithm.

• The Korean Journal of Food And Nutrition
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• v.13 no.6
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• pp.602-610
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• 2000

Taekukkwon was practiced far health previously. The experimental group consisted of undergraduate and graduate students practising in the above disciplines at Myong Ji University. The group consisted of three female and three male students and the aim of this research was to measure the brain wave change for opened and closed eyes. The result of this research are as follows. Firstly, when students were subjected to basic open eye brain wave tests, beta-waves displayed for all regions of the brain. In the frontal region fast beta-waves were displayed and in the central region alpha-waves were displayed. Secondly, in the closed eye brain wave tests, the control group displayed beta-waves in some regions and alpha waves in external and internal regions. For all students\` brain-wave patterns, the amplitude of the alpha-wave was low and the frequency was high. In some students theta-waves were displayed. Taekukkwon practice relaxes the mind and body and helps relieve social stress which shows that taichichuan practices is beneficial. Finally, characteristics of the subjects were mostly type A so the personalities of the subjects were fast and aggressive. This research shows a definite link between personality and personal relationships with beta-waves emissions. So, further research is required in the future to investigate this relationship. The subjects consumed too large amount of foods so it was necessary to change their dietary habits taking into consideration on total calories, fats, and protein. It was also necessary to carrying out nutrition education to the students in emphasizing appropriate attitudes in general health and dietary behavior.

• Korean Journal of Ichthyology
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• v.20 no.2
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• pp.97-104
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• 2008

Comparative study of retinal structure in two Korean endemic freshwater fishes, Zacco koreanus and Pseudobagrus koreanus, was carried out by light and scanning electron microscopy. In the visual cell layer comprised of cone cells and rod cells, the cone cells showed a distinct difference between both species. Z. koreanus had two types of cone cells, single cone cells including a long single and short single cone cells, and double cone cells, whereas P. koreanus had only one type of single cone cells having no its short single and long single cones. Meanwhile, the cone cells of Z. koreanus were arranged in more compact-rowed pattern, but it was more loose and irregular in P. koreanus. Based on field observation, Z. koreanus is mainly a epipelagic or sometimes benthopelagic and a diurnal fish with a round and large eye, while P. koreanus is a demersal and nocturnal fish with an oval and small eye. Therefore, the difference in the retinal structure of two species seems to be closely related to their ecological habitats.