• Advanced Composite Materials
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• v.17 no.1
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• pp.25-40
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• 2008

The research and development in soundproof materials for preventing noise have attracted great attention due to their social impact. Noise insulation materials are especially important in the field of soundproofing. Since the insulation ability of most materials follows a mass rule, the heavy weight materials like concrete, lead and steel board are mainly used in the current noise insulation materials. To overcome some weak points in these materials, fiber reinforced composite materials with lightweight and other high performance characteristics are now being used. In this paper, innovative insulation sheet materials with carbon and/or glass fabrics and nano-silica hybrid PU resin are developed. The parameters related to sound performance, such as materials and fabric texture in base fabric, hybrid method of resin, size of silica particle and so on, are investigated. At the same time, the wave analysis code (PZFlex) is used to simulate some of experimental results. As a result, it is found that both bundle density and fabric texture in the base fabrics play an important role on the soundproof performance. Compared with the effect of base fabrics, the transmission loss in sheet materials increased more than 10 dB even though the thickness of the sample was only about 0.7 mm. The results show different values of transmission loss factor when the diameters of silica particles in coating materials changed. It is understood that the effect of the soundproof performance is different due to the change of hybrid method and the size of silica particles. Fillers occupying appropriate positions and with optimum size may achieve a better effect in soundproof performance. The effect of the particle content on the soundproof performance is confirmed, but there is a limit for the addition of the fillers. The optimization of silica content for the improvement of the sound insulation effect is important. It is observed that nano-particles will have better effect on the high soundproof performance. The sound insulation effect has been understood through a comparison between the experimental and analytical results. It is confirmed that the time-domain finite wave analysis (PZFlex) is effective for the prediction and design of soundproof performance materials. Both experimental and analytical results indicate that the developed materials have advantages in lightweight, flexibility, other mechanical properties and excellent soundproof performance.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.2
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• pp.112-121
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• 2007

In occasion of soil loss happened in a basin, soil in the near of a stream may flow into the stream easily, but in case that soil is far away from the stream, sediment yield transferred to rivers by rainfall diminishes. To forecast sediment yield of a stream is an essential item for management of basins and streams. Therefore, sediment yield of soil loss produced from a basin is needed to be calculated as accurate as possible. Purpose of the present research is to calculate soil erosion amount in a basin and to forecast sediment yield flowed into a stream by rainfall and analyze sediment yield in the stream. There are various methods that analyze sediment yield of rivers. In the present study, the soil erosion amount was calculated using Revised Universal Soil Loss Equation(RUSLE) and GRID, and sediment yield was calculated using sediment delivery ratio and empirical methods. DEM data, slope of basin, soil map and landuse constructed by GIS were used for input data of RUSLE. The upstream area of the Yeongsan river basin in Gwangju metropolitan city was selected for the study area. Three methods according to the calculation of LS factor were applied to estimate the soil erosion amount. Two sediment delivery ratio methods for the respective methods were applied and, correspondingly, six occasions in sediment yield were calculated. In addition, the above results were compared by relative amount with estimation by the empirical method of Ministry of Construction & Transportation. Sediment yield calculated in the present study may be utilized for the plan, design and management of dams and channels, and evaluation of disaster impact.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.6
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• pp.367-374
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• 2019

We investigate the effect of soil-structure interaction (SSI) on the response of LNG storage tanks to vertical seismic excitation depending on the type of foundation. An LNG storage tank with a diameter of 71 m on a clay layer with a thickness of 30 m upon bedrock, was selected as an example. The nonlinear behavior of the soil was considered in an equivalent linear method. Four types of foundation were considered, including shallow, piled raft, and pile foundations (surface and floating types). In addition, the effect of soil compaction within the group pile on the seismic response of the tank was investigated. KIESSI-3D, an analysis package in the frequency domain, was used to study the SSI and the stress in the outer tank was calculated. Based on an analysis of the numerical results, we arrived at three main conclusions: (1) for a shallow foundation, the vertical stress in the outer tank is less than the fixed base response due to the SSI effect; (2) for foundations supported by piles, the vertical stress can be greater than the fixed base stress due to the increase in the vertical impedance due to the piles and the decrease in radiation damping; and (3) soil compaction had a miniscule impact on the seismic response of the outer tank.

• Korean Journal of Health Education and Promotion
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• v.26 no.5
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• pp.97-113
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• 2009

Objectives: This study was conducted to identify the intervention effects on health efficacy and health knowledge related to health behaviors for improving cardiovascular health in elementary school children. Methods: A repeated measure, pre-post-test design was used to identify the intervention effect on health efficacy and health knowledge among 5th grade school children. Intervention consisted of a curriculum classroom intervention and parent intervention. Health efficacy, health knowledge, and perceived parental monitoring were measured for testing intervention effect. A sample of 219 participants completed a baseline pre-test and two tests during intervention and after intervention from March to July 2004. Results: Mental health efficacy improved significantly from baseline test to the test after intervention (F = 32.88, p < 0.0001). Physical health efficacy also significantly increased during intervention (F = 50.51, p < 0.0001), but did not significantly change after parent intervention. Health knowledge increased significantly from baseline test to the test after education (F =10.23, p < 0.0001), but decreased after parent intervention. Perceived parental monitoring had a significant impact on mental health efficacy and physical health efficacy. Conclusion: The findings support school-based cardiovascular health promotion intervention as effective in improving health efficacy and health knowledge. Parental influence should also be considered to maintain improved health efficacy and health knowledge by thinking process in the intervention for elementary school children.

• Journal of the Korea Convergence Society
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• v.11 no.9
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• pp.261-266
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• 2020

The purpose of the Convergence study is to analyze the impact of students' satisfaction and educational performance through research on overall educational service quality factors for beauty academies. The subjects of the study were conducted from March 29 to April 12, 2020 for those in their 10s and 40s attending beauty academies in Seoul, Gyeonggi-do and Incheon, and 377 surveys were analyzed and used for research. Multiple regression analysis was performed using the SPSSWIN 21.0 program for research purposes. As a result of the study, the higher the level of empathy, reliability, responsiveness, type, and certainty of educational service quality, the higher the satisfaction level of the class. The higher the satisfaction level, the higher the educational performance. Based on these research results, measures to improve the quality of education services that can enhance the satisfaction and educational performance of beauty academies should be improved by diversifying educational methods and contents and enhancing the quality of education and service expertise. The expertise of education should be strengthened to improve competitiveness. Therefore, follow-up research is needed to develop various programs to enhance future course satisfaction and educational performance and to develop education methods to enhance the quality of beauty education services.

• Journal of Korean Physical Therapy Science
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• v.18 no.1
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• pp.21-32
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• 2011

Objective: This study was conducted to describe physical therapists' attitudes and beliefs towards Korean Government's National Long Term Care Insurance Program implemented last July 2008. Design: A survey research. Methodology: Participants were 143 physical therapists working in General Hospitals or University Hospitals in Busan, Korea. Each of the participants completed a questionnaire which was comprised of 22 questions. Among the 22 questions, 7 of these were independent variables such as gender, age, career, etc. while 15 of these questions were dependent variables such as the subject's expectations and reactions on the said program, opinions of the participants on the impact of the program to old people's families and relatives, participant's sentiments on social effects of this program to the society, etc. Data collection was conducted from the $20^{th}$ of July to the $5^{th}$ of August, 2008. Data were analyzed by Chi-square test, frequency and cross tabs using SPSS/PC program. Results: Based on the survey conducted, it showed that 50.3% were female respondents, 53.8% were on their twenties, 31.5% of the total respondents were married and that a percentage of 82.4% had working experiences below 10 years. About 80.4% of respondents were satisfied of their jobs and 32.4%of the respondents graduated from three - year college degree, 49.3% of the respondents graduated from four-year college degree. 95.1% of the total respondents knew the existence of the national long term care insurance program of the government and almost 78% got the information of the said program via internet, news paper or T.V. About 86% of the respondents believe that there will be future improvements in the quality of life in Korea through the said program and 82% said that there will be an increase sense of responsibility among family members to take care of their old relatives. 67.2 % of respondents believe that problems regarding old people will be solved through the government's national long term care insurance program. In aspect of Physical Therapy, 50% of the respondents expected generation of more jobs especially to physical therapists and 95% of the respondents want to work in any position in the said program especially those are more experienced ones. Conclusion: Physical Therapists in Korea are aware of the existence of the National Long Term Care Insurance Program of the Korean Government. Based on the gathered results from the survey, many experienced physical therapists of the country wanted to acquire positions in the said program especially that their expertise are needed in the said field. Through this study, it is evident that many physical therapists of the country have positive vibes on the said program and are optimistic on the outcomes of the said insurance program.

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.288-293
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• 2016

Purpose: The purpose of this study was to investigate the key factors in designing a three-wheeled two-row soybean reaper (riding type) that is suitable for soybean production, and ensure worker safety by proposing optimal work conditions for the prototype of the designed machine in relation to the slope of the road. Methods: A three-wheeled two-row soybean reaper (riding type) was designed and its prototype was fabricated based on the local soybean-production approach. This approach was considered to be closely related to the prototype-designing of the cutter and the wheel driving system of the reaper. Load distribution on the wheels of the prototype, its minimum turning radius, static lateral overturning angle, tilt angle during driving, and The working and rear overturning (back flip) angle were measured. Based on the gathered information, investigations were conducted regarding optimal work conditions for the prototype. The investigations took into account driving stability and worker safety. Results: The minimum ground clearance of the prototype was 0.5 m. The blade height of the prototype was adjusted such that the cutter was operated in line with the height of the ridges. The load distribution on the prototype's wheels was found to be 1 (front wheel: F): 1.35 (rear-left wheel: RL): 1.43 (rear-right wheel: RR). With the ratio of load distribution between the RL and RR wheels being 1: 1.05, the left-to-right lateral loads were found to be well-balanced. The minimum turning radius of the prototype was 2.0 m. Such a small turning radius was considered to be beneficial for cutting work on small-scale fields. The sliding of the prototype started at $25^{\circ}$, and its lateral overturning started at $39.3^{\circ}$. Further, the critical slope angle for the worker to drive the prototype in the direction of the contour line on an incline was found to be $12.8^{\circ}$, and the safe angle of slope for the cutting was measured to be less than $6^{\circ}$. The critical angle of slope that allowed for work was found to be $10^{\circ}$, at which point the prototype would overturn backward when given impact forces of 1,060 N on its front wheel. Conclusions: It was determined that farmers using the prototype would be able to work safely in most soybean production areas, provided that they complied with safe working conditions during driving and cutting.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.1
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• pp.81-88
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• 2020

Flight data recorder is a equipment that records data required for investigation of aircraft accidents and should be developed in compliance with the ED-112A standard. Unlike general data storage device, flight data recorder must be able to recover data after an aircraft accident, requiring a housing and a memory board to protect data in extreme environments. To attain this performance, we designed a housing that can withstand the test by analyzing the physical environment of the impact, shear/tensile, penetration resistance and static crush test of the crash survival test and minimized the size and weight compared to the existing one in consideration of the installation of the aircraft in this paper. Insulation material and thermal block material were applied to endure high and low temperature fire so that the internal temperature does not rise above 150℃ even in 260℃, 10 hour environment. In addition, the memory board is designed to minimize the size and we devise a hoping programming method to prevent continuous data loss of more than 16 seconds. Through this, Crash protected memory module that satisfies ED-112A was completed.

• Journal of the Korean Society of Safety
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• v.34 no.6
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• pp.13-21
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• 2019

Leakage accidents in businesses dealing with hazardous chemicals can have a great impact on the workers inside the workplace, as well as residents outside the workplace. In fact, there were cases where hazardous chemicals leaked from many businesses. As a result, the Chemicals Control Act(CCA) was enacted in 2015, the Ministry of Environment introduced an Off-site Risk Assessment(ORA). The purpose of the ORA is to secure safety from the installation of the design of the workplace facilities so that chemical accidents of hazardous chemical handling facilities do not cause human or physical damage outside the workplace. In general, the ORA qualitatively determines where a protected facility is within the scope of the accident scenario. However, elderly who belong to the sensitive group is more sensitive than the general group under the same chemical accident effect, and the extent of the damage is serious. According to data from the Korea National Statistic Office, the number of elderly people is expected to increase steadily. Therefore, a quantitative risk analysis considering the elderly is necessary as a result of a chemical accident. In this study, accident scenarios for 14 locations were set up to perform emergency evacuation due to toxic gas leakage of Cl₂(Chlorine) and HF(Hydrogen Fluoride), and the effects of exposure were analyzed based on the evacuation velocity difference of age 20s and 60s. The ALOHA(Areal Locations of Hazardous Atmospheres) program was used to calculate the concentration for assessing the effects. The time of exposure to toxic gas was calculated based on the time it took for the evacuation to run from the start point to the desired point and a methodology was devised that could be applied to the risk calculation. As a result of the study, the relative risk of the elderly, the sensitive group, needs to be determined.

• Hwankyungkyoyuk
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• v.20 no.2
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• pp.93-107
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• 2007

Livestock agriculture plays an essential role Hongsung's economy. Unfortunately, if manure is manage properly it can contaminate water and pollute the air. The purposes of this study were to provide awareness of environmental impact and to design educational programs with sustainable agriculture. I used the specific steps of processes. First, collecting informations through survey on environmental awareness of livestock farmers in Hongsung-gun and recognizing the tendencies. Second, analyzing on educational status of livestock farmers. Third, finding objectives of environmental educational programs. At the end of processes, establishing programs which concerning on environmental education. I used two research methods to gather and analyze the data for developing an environmental education program. The first one is a general survey among 50 livestock farmers from Hongseong-gun, Chungcheongnam-do. The second one is the in-depth interviews with specialists in environmental education and government officials from the central government - the Ministry of Agriculture and Forestry - and the local government - Hongsung-gun who are in charge of livestock farming. I found the following results from this research. First, most livestock farmers replied with 'highly likely' to the five items on the recognition of the necessity of environment preservation, whereas only 38.7% answered with 'likely' to the item on the environmental pollution caused by livestock farming. This shows the tendency that they have less recognition of the reality than necessary. Second, most of the contents among 5 areas(knowledge, recognition, function, attitude, and participation) are the knowledge areas. That results are analyzed training materials for livestock farmers made by Hongsung-gun in 2004 and in 2005 by using goal categories suggested in the Tbilisi Resolution. Third, after analyzing the survey and in-depth interviews, I found that the need for education to recognize the environmental pollution, environmental protection and recycling of the livestock waste. We can summarize conclusions from this research. First, we need on educational program improve the livestock farmers' recognition of importance in environmental protection. Second, it is necessary to develop educational program with the viewpoint that livestock waste is not one of the culprits of the environmental pollution, but a recyclable resource. Third, contents of the environmental education program, should include all the educational elements, namely, knowledge, recognition, attitude, function and participation. The education for livestock farmers requires a research on the environmental education program that can be used with crop farmers who can use the resources recycled from the livestock waste from the viewpoint of recycling resources. This research is focused on the collection and analysis of the basic data for developing an environmental education program and the composition of the program. A further research on the implementation and assessment of this program is required.