• Journal of Power System Engineering
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• v.17 no.6
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• pp.25-32
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• 2013

Biodiesel is technically competitive with it and offers technical advantages over conventional petroleum diesel fuel. Biodiesel is an environment friendly alternative liquid fuel that can be used in any diesel engine without modification. In this study, (dP/dCA)max and heat release, emission characteristics with different fuel injection timings are compared between diesel fuel and biodiesel in the D.I. diesel engine with T/C. The engine was operated at five different fuel injection timings from BTDC 6deg to 14deg at 2deg intervals and with four different loads at engine speed of 1800rpm. The experiments in a test engine showed that ranges between low and high of (dP/dCA)max got narrower, as the engine load increased, BD blend rate increased, and fuel injection timing was delayed. Cumulative heat release increased with the advanced fuel injection timing. NOX emissions decreased with the delays of fuel injection timing.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.2
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• pp.359-364
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• 2008

Using multi beam echo sounder, side scan sonar and scuba diving equipment, ceramic type, uneven type and semicircle-ramus type reefs into sandy bottom were ascertained, the depth of submersion in 7.2-10.3m on the coast of Gangneung, East of Korea, forty uneven type artificial reefs(AR) were totally buried into the sandy bottom. Two of five semicircle-ramus type ARs had only of their top area exposed. For most of the 45 ceramic reefs, only the upper 25-150cm of ARs were visible. The burial pattern is different in west and east side of the reefs, where the east side is deeply buried compared to the west side. From these results. it is recommended that sufficient analysis of bottom structure and materials especially in the sandy sea area should be undertaken in order to determine the best type of artificial reefs to be deployed and the best location for depoloyment.

• Korean Journal of Pharmacognosy
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• v.40 no.4
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• pp.376-381
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• 2009

The compositional analysis and the peroxynitrite ($ONOO^-$) scavenging assay were undertaken to demonstrate beneficial dietary effect of lettuce (Lactuca sativa L., Compositae). Quinic acid derivatives of the seven cultivars were qualitatively and quantitatively analyzed by HPLC to lead to the finding of 3,4-di-O-caffeoyquinic acid and 3-O-p-coumaroylquinic acid and their contents ranged over 2.72-4.47 mg/g and 8.97-23.26 mg/g, respectively. A cultivar Hacheong had the highest quantity of quinic acid derivatives. The peroxynitrite scavenging effect of the five cultivars (Jangsu, Gosina 27, Gopung, Yeolpungjeogchima, and Mipungjeogchugmyeon) were ranged over 7.45-8.26${\mu}g$/ml as $IC_{50}s$ while those of Hacheong and Mihong had less effect ($IC_{50}$ >10 ${\mu}g$/ml).

• Journal of the Korean Society of School Health
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• v.23 no.2
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• pp.256-265
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• 2010

Purpose: The purpose of this study was to identify the psychological problems of the children in early stage and provide basic data for develop the children's mental health promotion programs. Methods: There were 270 subjects who were fist and forth grade of elementary school and the data was collected through their parents. This study use Child Problem-Behavior Screening Questionnaire that was divided into five sub-scales, including internal problems, external problems, cognitive problems, abuse problems and psychosomatic problems. Each sub-scales have one cutting points, children whose scores above the cutting points means abnormal in correspond subscale. Results: 1) The most appearing problems was psychosomatic problems with 10.8% of subjects and next internal problems with 8.6% of subjects in elementary school student. 2) For distribution of mental behavior development according to gender, there was significant difference in psychosomatic problems between male and female (p =.009). 3) For distribution of mental behavior development according to grade, the results showed that significant difference in internal problems (p =.000) and total scores of CPSQ (p =.012) between first grade and forth grade. Conclusion: When we develop children's mental health promotion program, it is necessary to considerate the gender and grade characteristics.

• ALGAE
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• v.26 no.1
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• pp.61-71
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• 2011

Thirty populations of Chondrus crispus Stackhouse from Nova Scotia were collected during the years 1993 to 2011. Taken from estuaries, wave exposed open coasts, high intertidal rock pools and shallow subtidal habitats, the populations were evaluated for relative abundance of tetrasporophytic and gametophytic life history phases. Over 2,800 thalli were characterized using the resorcinol-acetal test to distinguish the kappa- and lambda-carrageenan containing fronds of gametophytes and tetrasporophytes, respectively. These populations had $77{\pm}5%$ gametophytes (mean ${\pm}95%$ confidence interval), with most populations having gametophyte : sporophyte ratios ranging from 2 : 1 to 9 : 1. No population had a dominance of tetrasporophytes, although two populations had 1 : 1 ratios. A meta-analysis of our data along with previously published accounts showed no significant changes in gametophyte dominance with respect to hypothesized gradients of wave exposure, salinity, or water depth. Significant changes occurred in ratios at five sites where replicate sampling occurred in different years. We conclude that C. crispus in Maritime Canada has a natural ratio of 3 : 1 or greater in stable conditions, and that lower ratios represent recovery from disturbance in which bare substratum is created that is subsequently colonized by carpospores from remaining gametophytic thalli.

• The Korean Journal of Pain
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• v.14 no.1
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• pp.19-25
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• 2001

Background: Transcutaneous electrical nerve stimulation (TENS) has been used widely, but its effects are controversial. This is probably due to the varying intensity and type of pain. We designed a study to assess the effects of the TENS on the RIII nociceptive flexion reflex as the resting pain level and the temporal summation as a repeated, movement related pain in 7 normal volunteer subjects. Methods: High frequency (80 Hz), non-noxious TENS was applied over the left popliteal fossa for 20 minutes. Ipsilateral RIII reflexes induced by single electrical stimulus and temporal summation of pain responses to repeated stimuli (five stimuli at 2 Hz) were recorded before, during (just before stopping), and subsequently at 20 minutes after TENS. Results: R (III) nociceptive flexion reflex activity during and after TENS was more significantly decreased than before treatment. However, the temporal summation threshold was not changed. Conclusions: We conclude that high frequency, non-noxious TENS could be effective on resting pain relief in the same segment but not on the movement related pain.

• The Journal of Korea Robotics Society
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• v.15 no.2
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• pp.124-130
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• 2020

This paper designed modular agricultural robotic platform capable of a variety of agricultural tasks to address the problems caused by a decline in agricultural populations and an increase in average age. We propose a modular robotic platform that can perform many tasks required in field farming by replacing only work modules with common robotic platforms. This platform is capable of steering while driving on four wheels in an upland environment where farm work is performed, and an attitude control module is attached to each drive module to control the attitude of the platform. In addition, the width of the platform is designed to be variable in order to operate in various ridges according to the crop cultivation method. Finally, we evaluated five items: variable width, gradient, attitude control angle, step and road speed in order to carry out the farming industry while maintaining a stable posture.

• Korean Institute of Interior Design Journal
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• v.22 no.2
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• pp.140-148
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• 2013

The purpose of this study is to examine the current status of allergic diseases associated with the housing environment and the psychological attitude of residents towards relevant risk factors. This study surveyed 1,200 people. In the first round, 200 participants were questioned through direct survey methods, while 1,000 participants filled out an online survey in the second round. Selected study subjects consisted of allergic diseases known to be closely related to housing environment factors. With advice from medical experts, the analysis included the examination of the prevalence status regarding five types of allergy-related diseases-allergic conjunctivitis, allergic rhinitis, allergic dermatitis, asthma and headache-with the range of disease incidence set within the past ten years. The survey was conducted on all age groups except those nine years old and younger, and the findings are as follows. Allergic diseases were found to be more prevalent among women than men. Residents identified effective methods for the alleviation and treatment of allergic diseases as ventilation, use of environmentally-friendly finishing materials, maintenance of a clean living space through cleaning or washing, and sunlight exposure. Residents' understanding of allergic diseases varied depending on their experience with such diseases and residential characteristics.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2019-2024
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• 2014

This paper presents a method to optimize the design of a planar-type antenna and reduce the number of design parameters for rapid computation. The electromagnetic characteristics of the structure are analyzed, and Taguchi method is used to identify critical design parameters. Adaptive particle swarm optimization, which has a faster convergence rate than particle swarm optimization, is used to achieve the design goal effectively. A compact dual-band USB dongle antenna is tested to verify the advantage of the proposed method. In this case, we can use only five selected geometrical parameters instead of eighteen to accelerate the optimization of the antenna design. The 10 dB bandwidth for return loss ranges from 2.3 GHz to 2.7 GHz and from 5.1 GHz to 5.9 GHz, covering all the WiBro, Bluetooth, WiMAX, and 802.11 b/g/n WLAN bands in both simulation and measurement. The optimization process enables the antenna design to achieve the required performance with fewer design parameters.

• Korean Journal of Human Ecology
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• v.15 no.1
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• pp.71-81
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• 2006

The purpose of this study is to examine the differences in young children's multiple intelligence and social behaviors based not only on Montessori and general programs of day care centers but also on their gender and social- demographic factors. The subjects were 329 young children (182 boys and 147 girls aged from four to five) from two day care centers in Cheongju city. The instruments used in this study were HAPI (Hillside assessment of Perceived Intelligence) to measure the surveyee's multiple intelligence and Park & Lee's scale to measure their social behaviors. The frequencies, percentiles, mean, standard deviations, Cronbach a, t-teat, F and LSD were used to analyze the collected data through SPSS WIN program. The results of this study are as follows: 1) As for young children's multiple intelligence, there are differences according to young children's gender, order of birth, parents' level of education and teacher's working period out of social-demographic factors. 2) As for the young children's social behavior, there are differences according to young children's gender, mother's level of education and teacher's working period out of social-demographic factors.