• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.615-622
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• 2020

Frangible bullets, which are shredded after impact on a target, reduce the possibility of both ricochet and unexpected injury in shooting training and in mission acts in dams, nuclear power plants, and cultural properties. Reducing the levels of hazardous materials in shooting ranges, such as lead, has become an important agenda for the government and environmental groups. In this study, the shape of a frangible bullet was designed for efficient shredding, and the safety and reliability were confirmed by actual firing under different process conditions. In addition, the physical characteristics, such as compaction pressure, density, and frangibility of each process, were compared by analyzing the microstructure of the sintered frangible bullet. The experiment revealed the smallest fragmentation after impact on the target under the following conditions: Cu-Sn 85:15; sintering temperature, 600℃; sintering time, one hour. Further development of the process conditions and experimental methods will contribute to the performance and environmental improvement of a frangible bullet.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.9
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• pp.469-475
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• 2016

The study is the result of an practical operation analysis for the full scale fishery product wastewater treatment plant with immersed MBR (iMBR) process. Since fishery product industries show a wide range of wastewater generation by the season, design and operation of the equalization basin are very important factor. The aeration system for the equalization basin mixing can save the chemical consumption for followed system through the restriction of acid fermentation. The concentrations of wastewater primary DAF process treated were BOD 2,291 mg/L, $COD_{Mn}$ 530 mg/L, SS 256.8 mg/L, T-N 38 mg/L, T-P 13.5 mg/L respectively. It was considered that iMBR is the most efficient biological process for high salinity content wastewater since It is irrelevant to the capability of the sludge precipitation. SADp and SADm were 0.31, $26.5m^3/hr{\cdot}m^3$ respectively. In iMBR process, the critical F/M ratio was derived at 0.08~0.10 gBOD/gMLSS by analysing the correlations between MLSS, normalized TMP and temperature. The effluent concentrations were BOD 1.8 mg/L, $COD_{Mn}$ 12.4 mg/L, SS 1.0 mg/L, T-N 7.85 mg/L, T-P 0.1 mg/L and removal efficiencies were 99.9%, 97.6%, 96.3%, 95.7%, 97.8% respectively.

• Journal of Navigation and Port Research
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• v.30 no.6 s.112
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• pp.439-446
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• 2006

In ship structures many of the structural plates have cutouts, for example, at inner bottom structure, girder, upper deck hatch, floor and dia-frame etc. In the case where a plate has a cutout it experiences reduced buckling and ultimate strength and at the same time the in-plane stress under compressive load produced by hull girder bending will be redistributed In general, actual ship structure adopted reinforcement of stiffener around the cutout in order to preventing from buckling so it need to examine a buckling and ultimate strength behaviour considering a cutout because In many ship yards used class rule for calculating buckling strength but it is difficult to evaluate perforate stiffened plate with random size. In the present paper, we investigated several kinds of perforated stiffened model from actual ship and then was performed finite element series analysis varying the cutout ratio, web height, thickness and type of cross-section using commercial FEA program(ANSYS) under compressive load.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.2
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• pp.120-125
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• 2015

With rapid urbanization, the volume of traffic in urban area has been significantly increased. This in turn led to problem which can be described as Road Traffic Noise. Currently, to alleviate the road traffic noise damage, a demand for installation of soundproofing walls is rising. Among different shapes of soundproof walls being installed, the reflection-type acoustical insulation panel is highly drawing attentions of residents due to the fact that it does not obstruct their field of vision in contrast with the opaque acoustical insulation panel. On the other hand, improving the soundproofing wall of the reflection-type acoustical insulation barrier panel needs to be focused on since it has a possibility to cause a secondary damage by reflected sounds. Therefore, in this research, study has been carried out to improve the forms in order to minimize travelling of reflected sounds through changing the frontal surface shape and geometrical shape of the reflection-type soundproofing panel. A result from comparison between the normal reflection-type soundproofing panel and the improved soundproofing panel, with reduction effects in the noise reflection, showed that the curved type of soundproofing panel has an impact on reducing the noise up to 1.5 dB. Furthermore, from the research conducted, it appears that the increase and decrease in the reflected sounds can be changeable depending on various design factors. Thus, it turns out that the study shows a potential possibility to develop a reduction technology of the reflected sounds pertaining to overall condition on the soundproofing walls.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.421-431
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• 2018

The purpose of this study is to develop a diaper hygienic care education program for caregivers and to investigate the effects of the diaper hygienic care knowledge and performance ability on diaper hygienic care. A quasi-experimental research with nonequivalent control group pretest-post test design was conducted. The subjects for the study 50 caregivers working in long-term care facilities in Y-gun, Chungcheongnam-do were selected from the 25 experimental group and the 25 control group. The collected data were analyzed using SPSS Window 22 version. diaper hygienic care education program consisted of 4 sessions in total. According to results of the education program, the diaper hygienic care knowledge increased after the post-test($M{\pm}SD=4.88{\pm}0.23$) compared to the pre-test score($M{\pm}SD=4.64{\pm}0.23$), but not be statistically significant between the two groups(t = 1.253, p = .216). The performance ability of diaper hygienic care was significantly increased ($M{\pm}SD=2.89{\pm}0.15$) compared to the pre - score($M{\pm}SD=1.86{\pm}0.18$) and there was a statistically significant difference(t = 12.694, p =. 001). Thus, the developed diaper hygienic care education program is expected to contribute to improve nursing hygienic care ability of nursing caregivers.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.115-127
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• 2007

Developed countries, especially in road construction and management fields, introduce new road porjects such as National Scenic Byways Program(NSBP program) in USA and the Eco-road project in Japan. This study develops a conceptual model for deploying new road projects in Korea. The four step approach is suggested to create new road projects, including foundation of an act based on the existing Road Act, creation of new road project ideas, development of evaluation process and guidelines, and enhancement of an administrative scheme. To create new road projects, three different ways are devised; (1) designation of national roads having uniqueness in overall spectrum, (2) designation of roads having intrinsic values in a different aspect, (3) designation of single structures of engineering outcomes such as bridges, tunnels, new design techniques, considerable Value Engineering output, and well analyzed Life Cycle Cost Analysis practices. For the evaluation process, NSBP program of USA and/or Sustainable City Award program of Korea would be recommended. An administrative scheme and integrated funding process for the new road projects are also suggested based on evaluation of tasks of each team or division of Korea Ministry of Construction and Transportation.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.1-19
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• 2008

This research is to analyze the force on landing 3 Type of Halfpipe Curves(Ellipse, Circle, Brachistochrone) based on the mechanical calculation of normal force on a sloping surface. Jumping off a platform on a bard horizontal surface, the flexing of the legs, the softness of the snow, the angle of the landing surface, initial velocity and the forward motion of the snowboarder can contribute to reducing the force on landing. But halfpipe is significantly determined by the curvature of surface. It is definitely verified that the Brachistochrone curve is more safety than others. However currently using the Ellipse curve is mostly safe too. If we consider the efficiency of construction, we can easily think there is no use of another curves except normal ellipse curved halfpipe. It would better that geometrically verity curved halfpipe should be designed for improving fluent skills to snowboarders. This methode of research can be a model of scientifical research on sports safety how can sportsman reduce critical injury by designing optimal halfpipe facilities and manual.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1327-1334
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• 2014

Linear form of public works such as roads, railways and rivers, generally used as long work crossing administrative districts, can be several hundreds km length and narrow. These linear forms use SCM sheets, which do not include the quadrangle shape, to make a public announcement of topographical drawing in order to get the work approval. the Integrated measurement channel investigation and cadastral act that are established in 2009 apply the ITRF for the composition of design and construction books and coordinates of topographical map in order to get the work approval. However according to the article 5 of additional clause, while the cadastre is maintaining local coordinates, if there is a technical error in the content of the Public Announcement of Topographical Drawing that used the SCM, the question of responsibility of land borders and the efficacy or not of the announcement is raised as an administrative measure. After analysing the causes and enforcing coordinate conversion and correction taking into account linear form work's features, the result was reflected in the existing SCM. As a conclusion, the present study proposes the improvement of the procedures of the Public Announcement of Topographical Drawing.

• Journal of Digital Convergence
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• v.16 no.6
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• pp.213-222
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• 2018

This study purposed to verify the effects of knee balance taping therapy on knee pain and knee range of motion in the elderly with knee pain. The Quasi-experimental design, nonequivalent control group pretest-posttest was used in this study. Data collected from December 5 to 10, 2014. The participants were older than 60 with knee pain visiting senior community centers. Non-medicated elastic tapes were applied around the knee in the experimental group(n=21) and were not applied in the control group(n=19). Knee pain and range of motion were measured 3 times (before, after 1 hour, after 24 hours). Data were analyzed using ${\chi}^2$ test, Fisher's exact test, Mann-Whitney test, t-test, Repeated measure ANOVA with the SPSS version 21.0 program. The experimental group showed significantly decreased knee pain (F=34.03, p<.001) and increase in knee range of motion (F=7.83, p=.006). The results of this study confirm that knee balance taping therapy is an effective intervention for reducing pain and improving range of motion in elderly with knee pain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.1
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• pp.49-60
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• 2017

In this paper, we presented the result of the study on high-power handling capability of the X-band circular waveguide cavity filter configured at the output of high power amplifier(120 W) for geostationary satellites. The dual mode circular waveguide cavity filter with 6th order is selected and the physical model of the filter is designed after determination of the size of resonator from mode chart. Multipactor margin analysis is performed by the SEM method and the VMF method. The result shows that the VMF method predicts lower multipactor breakdown thresholds than the SEM method. Evaluating the multipactor margin obtained by the VMF method to ECSS criteria, we could decide to perform multipactor test. The multipactor test conducted in ESA facility shows that multipactor did not occur even until the RF power increased up to 540 W. In consequence, by both analysis and test, we could verify that the X-band circular waveguide cavity filter has the sufficient high-power handling capability to operate on orbit.