• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.32-42
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• 2013

In this paper, a wave-induced swirl water chamber (SWC) for breakwater and wave power generation is introduced and its applicability to wave power generation in the coastal waters of Korea is investigated. The SWC type of wave power generation is a way to drive a turbine using the unidirectional swirl flow that is induced in the back of a curtain wall of a breakwater due to incident waves. The typical wave characteristics are obtained by analyzing the annual statistical wave data from KHOA (Korea Hydrographic and Oceanographic Administration). A numerical analysis is carried out on the variations in the SWC entrance height, wave height, and different installation conditions. For the numerical analysis, a commercial code, Fluent based on FVM, is used. As the entrance height decreases, the mass flow rate through the entrance is rarely changed, whereas the magnitude of the flow velocity of the smaller entrance height is greater than the other ones, which is better for the formation of an SWC swirl flow inside and the flow kinetic energy at the entrance. In cases of installation conditions where a wall is place behind and under SWC, it has been shown that the mass flow rate through the entrance is greater than that in the open condition, and sufficient flow kinetic energy is generated in the entrance for wave power generation. However, the swirl flow kinetic energy is relatively small. Thus, in the future, it is necessary to study the swirl flow generation, which is affected by the SWC shape.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.27-32
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• 2022

There has always been a demand for orthodontic treatment. Orthodontic treatment allows tooth to be arranged by flexible arch wire fixed with tooth-attached brackets. Arch wire generate constant pressure to tooth brackets which moves the teeth to proper place. When the bracket transmits force, the braced wing of the bracket may deform. Deformed tie wing will lead to lost tension of elastic ligature. Then, lacking grip between tie wing and ligature might delay the tooth movement. Furthermore, tooth brackets used for orthodontic treatment make contact with in direct oral surface and this cause feeling of irritation that comes from height of tooth braces. This study suggests an optimal teethe bracket design to make up for inconvenience by shorten the height of bracket and complement the shape of bracket to reduce strain rate using finite element analysis. As a result, new optimal design of teethe bracket indicates lower strain rate of the bracket wing and takes good effects of shorten body height in terms of convenience.

• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.7-12
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• 2013

Environmental measurements in the many different types of horticultural farms were carried out to evaluate the ventilation performance for multi-span plastic greenhouses according to the eaves height, the number of spans, the existence of side wall vents and the position of roof vents. Hydroponic tomatoes were being cultivated in all experimental greenhouses, and ventilation rates of the greenhouses were analyzed by the heat balance method. It showed that the ventilation rate in the greenhouse with 4 m eaves height increased about 22% compared to the greenhouse with 2 m eaves height. The ventilation rate in the greenhouse with 9 spans decreased about 17% compared to the greenhouse with 5 spans. In the greenhouse with 9 spans, if there were no side wall vents, the ventilation rate showed about a third of the case that side wall vents were open. Overall, as the eaves height was higher and the number of spans was smaller in multi-span greenhouses, the natural ventilation performance was better. And the ventilation performance was best in the greenhouse which the eaves height was high and the position of roof vents was ridge, not gutter. Therefore, in order to maximize the natural ventilation performance, multi-span plastic greenhouses need to improve their structures such as that make the eaves height higher, place the roof vents on the ridge, install the side wall vents as much as possible, and the number of spans is limited to about 10 spans.

• Journal of Environmental Science International
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• v.12 no.12
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• pp.1245-1254
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• 2003

A numerical simulation for 11 February 1996 has been done to grasp main mechanisms of the occurrence of strong downslope winds near Gangnung area. The simulation performed by using ARPS (Advanced Regional Prediction System) showed that enhanced surface winds were not related with a reflection of vertically propagating gravity waves. Froude numbers were about 1.0, 0.4 and 0.6 for the atmosphere above Daekwanryoung and above a place located 220km upstream, and above another place located 230km downstream from the Taebak mountains, respectively. This suggested that as a subcritical flow ascended the upslope side of the Taebak mountains, Froude numbers would tend to increase according to the increase in wind speed, and near the crest the flow would become supercritical and continue to accelerate as it went down the downslope side until it was adapted back to the ambient subcritical conditions in a turbulent hydraulic jump. Simulated Froude numbers corroborated the hydraulic jump nature of the strong downslope wind. In addition, the inversion was found near the mountain top height upstream of the mountains, and it was favorable for the occurrence of strong downslope winds.

• KIEAE Journal
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• v.15 no.2
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• pp.69-78
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• 2015

Purpose: The aim of this study was to analyze the elementary schoolchildren's the fear of crime in pedestrian environment of elementary school for providing the basic design resource. Method:In order to deal with that, the questionnaire survey on the elementary schoolchildren's the fear of crime were conducted in 5 elementary schools in Ilsan new town. The results of the 293 questionnaires survey were analyzed through SPSS program. Result: The main results were as follows. The level of fear of crime in pedestrian environment differed in these 5 elementary schools because of the width of pedestrian path, the concealed place around pedestrian path, the nearness of park, the height/shape/interval of trees, the number of car and the closure-watching in the school caused by fence and trees and so on. The level of fear of crime in pedestrian environment differed between that of boy groups and that of girls groups because of the number of emergency bell/telephon, the shape of pedestrian path, the number of security office, the number of car and the concealed place around pedestrian path and so on.

• Journal of the Korea Fashion and Costume Design Association
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• v.13 no.2
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• pp.1-11
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• 2011

As a result of comparison analysis on body types of Korean women in their twenties and Korean women residing in Japan, the following results had been found. 1. The comparison of 49 items in physical measurements between the Korean women in their 20's and Korean women residing in Japan resulted in the differences in 33 items. 2. The comparison of the factor analysis results for physical measurements did not reveal big differences. 3. The comparison of the physical shapes according to the grouping resulted in three types each for both groups, with different features for individual types. Women residing in Korea were classified into tall and normal body, normal height with obese body, and short and thin body. Women residing in Japan showed different characteristics with tall and obese body, short and thin body and normal height with obese body. As a result of this study, identical ethnic group was found to take on different body types resulting from sociocultural differences and difference in eating habits if their place of residence differs for a long time.

• International Journal of Fluid Machinery and Systems
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• v.2 no.1
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• pp.13-20
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• 2009

The effects of positively bowed blade on the aerodynamic performance of annular compressor cascades with large camber angle were experimentally investigated under different incidences. The distributions of the exit total pressure loss and secondary flow vectors of compressor cascades were analyzed. The static pressure was measured by tapping on the cascade surfaces, and the ink-trace flow visualizations were conducted. The results show that the value of the optimum bowed angle and optimum bowed height decrease because of the increased losses at the mid-span with the increase of the caber angle. The C-shape static pressure distribution along the radial direction exists on the suction surface of the straight cascade with large r camber angles. When bowed blade is applied, the larger bowed angle and larger bowed height will further enhance the accumulation of the low-energy fluid at the mid-span, thus deteriorate the flow behavior. Under $60^{\circ}$ camber angle, flow behavior near the end-wall region of some bowed cascades even deteriorates instead of improving because the blockage of the separated flow near the mid-span keeps the low-energy fluid near the end-walls from moving towards the mid-span region, and as a result, a rapid augmentation of the total loss is easy to take place under large bowed angle. With the increase of camber angle, the choice range of bowed angle corresponding to the best performance in different incidences become narrower.

• Journal of Korean Physical Therapy Science
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• v.5 no.4
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• pp.763-775
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• 1998

Some segment or segments of the body must compensate for the heel, and the higher the heel the greater the compensation. Such compensation was once generally thought to take place in the lumbar region and therefore to increase the lumbar lordosis. The purpose of this study is to analyze changes of lumbar sagittal curvature in barefoot and 6cm 12cm high-heel stance. We selected 19 subjects(11 males, 8 females} without history of lower back pain, significant spinal abnormality. And lateral view X-ray of lumbar region from T12 to S1 was taken of each individual. On each X-ray film, lumbar lordotic angle lumbosacral angle and lumbar segmental angles were measured by Cobb method. We drew the following interpretations from the analysis of measured variables of the lumbar region. 1. In comparison of barefoot 6cm heel 12cm heel stance, lumbar lordotic angle had a tendency to decrease according as the heel height was higher. The change in lumbar lordosis measured in high-heel stance was inconsistent with clinical forkelord of hyperlordosis in wearers of high-heeled. 2. Lumbar lordotic angle from T12 to L5 showed sex difference, and was more lordotic in female(p<0.05). 3. There was no sex difference in lumbosacral angle and lumbar segmental angles(p>0.05). 4. There was a significant correlation between lumbar lordotic angle and lumbosacral angle(r>0.60).

• Journal of Korean Society of Forest Science
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• v.35 no.1
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• pp.33-35
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• 1977

The mean height growth of 1-1 Picea abies seedlings originated from two provenances, i.e., Hartz above 600m of altitude and Fichtel (Ober Pfalzer basin below 800m) were measured. The progeny from Fichtel out grew those of Harz. about 70% as fast as did tree from Hartz. The variance due to replications was greater in Fichtel than in Hartz. 1-0. Quercus borealis seedlings showed vigorous height growth. All these experiments were performed at Yangsan-gun Habuk-myeon, south-east place in Korea.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.3
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• pp.157-163
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• 2019

As the drone industry has grown greatly in recent years, drones are being used or developed in many industrial fields such as image shooting, pesticide application, delivery service, food delivery etc. In this paper, therefore, we developed a program that takes a user's desired area at a certain height using a camera-equipped drone and obtains the area of the zone the user wants through image processing. The first user selects an area or a path. Afterwards, the drone flies and takes pictures, and then measures the user's needs. A digital image taken at a constant height and with the same resolution is composed of pixels, the area can be calculated easily if we know the number of pixels in the zone the user wants. Particularly, it is easy to calculate the area of various shaped zones, not terrain shapes such as triangles and squares. In addition, the total area of specific places of the entire zone can be calculated. With the program of this paper, anyone can easily calculate the area of the place the user wants using a drone rather than calculating the area through difficult formulas or specialized equipment.