• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.88-96
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• 2020

It were found that the heavyweight waste glass can be used as a construction materials including concrete from previous experimental studies. In this study, in order to evaluate the structural behavior of RC members using heavyweight waste glass as fine aggregate, a flexural behavior test was performed. And then, its results were compared with those obtained from non-linear finite element model analysis. From the results, when the heavyweight waste glass as fine aggregate in RC member, the area of compressive crushing and the number of cracks increased, however, the mean of cracking spacing decreased. Also it had reduced the ductility at high loading stage. For this reason, the same analysis method about the RC member using natural sand as fine aggregate did not predict the initial stiffness, yield load and maximum load on the flexural behavior of the RC members using heavyweight waste glass as fine aggregate. On the other hand, when it is analytically implemented the reduction of neutral axis depth due to developed compression crushing, the results of non-linear finite element analysis could be predicted the experimental results, relatively well.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.3
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• pp.277-291
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• 2020

Shield TBM is a tunnelling method that has a wider range of applications in the poor ground condition compared to conventional tunnels (Drill and Blast). Currently, a 13.3 m large-diameter slurry shield TBM is preparing for construction to pass under the Han River. Shield TBM is divided into slurry and EPB shield TBM, and management items during construction are different depending on each characteristic. In this paper, the equipment type, origin, application case and trouble case were analyzed for slurry shield TBM, which is mainly constructed in soft ground. In addition, 2D and 3D model tests were conducted on the condition of soil depth for the possibility of slurry leakage into front of the equipment, with appropriate chamber pressure. Based on this paper, it proposed to provide basic and reference data for proper excavation surface pressure and chamber pressure during construction of slurry shield TBM under soft ground conditions, and proposed measures to minimize stability and environmental decline due to slurry ejection.

• Korean Journal of Social Welfare Studies
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• v.44 no.3
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• pp.57-83
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• 2013

There has neither been enough research on how to approach the concept of active aging through an integrated view nor an examination to verify the relationship between preparation for old age and active aging in later life. Therefore, this research aims to verify that the elderly, who have prepared for their later life, affected their active aged life. In addition, by setting up self-efficacy and social support as mediator in the research model, this paper looks into the psycho-social resource mechanism of the relationship in depth. In order to verify the correlation of two variables, the Seoul welfare panel data, a mediating model structured by psycho-social resources created by Seoul welfare foundation in 2010, was used. The total sample size was a group of 1,492 elders aged over 65. When it came to our research methods, structured equation analysis was applied to verify the mediating effect and theoretical background. The results revealed that physical preparation, financial preparation, social preparation and leisure preparation directly affected their active aging level positively, thus, psycho-social resources showed a partial mediating effect between preparation for old age of the past and active aging level. The research implications are as follows. First, this research makes an effort to approach the concept of preparation for old age with an integrated perspective through making a construct by entire preparation types. Second, it will attempt to verify the relationship between preparation for old age in the past and active aging in terms of multi-dimension is meaningful. Third, this research reveals the function of psycho-social resource, self-efficacy and social support within the relationship. As far as the partial mediating effect is concerned, preparation for old age education for the middle-aged class should be modified as a decent field to enhance of the elderly.

• Journal of the Korean Geophysical Society
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• v.5 no.1
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• pp.9-18
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• 2002

We performed a long-term monitoring of self-potential(SP) using the Cu-CuSO₄non-polarizable electrode and copper-clad electrodes(CCE) in a test site in order to analyze the effects of surrounding environmental noises such as temperature, rainfall and soil moisture content on the electrodes. Analysis of the temperature dependence of the non-polarizable electrodes showed that is temperature coefficient was about +0.5 mV/°Fwhen its end was exposed to atmosphere while it was less than +0.5 mV/℃ when submerged into the subsurface, which reflects that there exists an 8 to 11 hour lag between temperatures at the depth of 15 cm and atmosphere. CCE was independent of atmospheric temperature in subsurface but showed temperature coefficient of 1.0 mV/℃ when exposed to atmosphere. Drifts of 1 to 2 mV recorded with the non-polarizable electrode directly related to the soil moisture content when it was buried in subsurface. Drift with CCE also showed similar trend to the soil moisture content, and 5 mV drift was recorded according to 5% of daily variation. The soil moisture content had strong effects on the measurement with CCE in rainfall since the flow potential is generated on the surface of the electrode.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.684-693
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• 2021

Purpose: The purpose is to establish a safe facility environment from abnormal voltages such as lightning by developing a smart land resistance measuring device that can acquire real-time land resistance data using Arduino. Method: This paper studied design models and application cases by developing a land resistance acquisition and analysis system with Arduino and a power line communication (PLC) system. Some sites in the wind power generation complex in Gyeongsangnam-do were selected as test beds, and real-time land resistance data applied with new technologies were obtained. The electrode arrangement adopted a smart electrode arrangement using a combination of a Wenner four electrode arrangement and a Schlumberger electrode arrangement. Result: First, the characteristic of this technology is that the depth of smart multi-electrodes is organized differently to reduce the error range of the acquired data even in the stratigraphic structure with specificity between floors. Second, IT convergence technology was applied to enable real-time transmission and reception of information on land resistance data acquired from smart ground electrodes through the Internet of Things. Finally, it is possible to establish a regular management system and analyze big data accumulated in the server to check the trend of changes in various elements, and to model the optimal ground algorithm and ground system design for the IT convergence environment. Conclusion: This technology will reduce surge damage caused by lightning on urban infrastructure underlying the 4th industrial era and design an optimized ground system model to protect the safety and life of users. It is also expected to secure intellectual property rights of pure domestic technology to create jobs and revitalize our industry, which has been stagnant as a pandemic in the post-COVID-19 era.

• Education of Primary School Mathematics
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• v.24 no.4
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• pp.175-187
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• 2021

The purpose of this study is to investigate the effects of solving multi-strategic mathematics problems on mathematical creativity and attitudes of the 6th grade students. For this study, the researchers conducted a survey of forty nine (26 students in experimental group and 23 students in comparative group) 6th graders of S elementary school in Seoul with 19 lessons. The experimental group solved the multi-strategic mathematics problems after learning mathematics through mathematical strategies, whereas the group of comparative students were taught general mathematics problem solving. The researchers conducted pre- and post- isomorphic mathematical creativity and mathematical attitudes of students. They examined the t-test between the pre- and post- scores of sub-elements of fluency, flexibility and creativity and attitudes of the students by the i-STATistics. The researchers obtained the following conclusions. First, solving multi-strategic mathematics problems has a positive impact on mathematical creativity of the students. After learning solving the multi-strategic mathematics problems, the scores of mathematical creativity of the 6th grade elementary students were increased. Second, learning solving the multi-strategy mathematics problems impact the interest, value, will and efficacy factors in the mathematical attitudes of the students. However, no significant effect was found in the areas of desire for recognition and motivation. The researchers suggested that, by expanding the academic year and the number of people in the study, it is necessary to verify how mathematics learning through multi-strategic mathematics problem-solving affects mathematical creativity and mathematical attitudes, and to verify the effectiveness through long-term research, including qualitative research methods such as in-depth interviews and observations of students' solving problems.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.3
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• pp.165-173
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• 2021

Purpose : Myofascial decompression is frequently mentioned as a method applied to cupping. The purpose of this study is to evaluate and compare active range of motion (AROM), muscle strength, and functional movement by applying myofascial decompression to the hamstrings. Methods : This study evaluated AROM, muscle strength, and functional movement by applying active movement myofascial decompression and static myofascial decompression to the dominant leg, respectively, in a crossover design conducted with normal adults (n=21) in their average 20s enrolled at G University in G city, Gyeongsangbuk-do. Active movement myofascial decompression was implemented for five minutes at a rate of 100 bpm to make the beats in flexion and extension respectively. Static myofascial decompression was only performed for five minutes while at rest. All of these interventions were performed at a cupping depth of two mm. After a one-week washout period, static was applied again to compare the same dependent variables. Results : Regarding AROM and muscle strength, both groups showed significant differences in the before and after results (p<.05). However, in the Functional Reach Aspect and Single Leg Hop test, the active movement myofascial decompression group showed better results. There was no statistical difference between the Active movement myofascial decompression group and Static myofascial decompression group in any dependent variable (p<.05). Conclusion : As a result of this experiment, both active movement myofascial decompression and static myofascial decompression had a positive effect on dependent variable. Therefore this study is meaningful in that it is easier and simpler to see the effect on flexibility, muscle strength, and functional movement just by implementing movement myofascial decompression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.601-610
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• 2021

The tidal current patterns at Keum River Estuary before and after the construction of coastal structures were compared according to the CASES. The depth-integrated and tidal difference treatment applied FLOW2DH numerical model was used for the tidal current predictions. The test conditions consisted of before construction of coastal structures (CASE1), after construction of coastal structures (CASE2), and the addition of watergate operation(CASE1Q and CASE2Q), and present (CASE3). CASE1 showed a stable tidal current pattern, such as a natural estuary. In CASE2, the tidal current velocities and directions of the Keum River Estuary were changed due to the installed coastal structures. In particular, the tidal current velocities of the Gaeya open channel sections (P5~P9) in CASE2 were calculated to be 10~30% larger than that of CASE1. In the case of the Gunsan Inner Harbor (P4), which is closest to the Geum River Estuary, the ebb flow rate was approximately 250~300% faster than that of other CASEs due to the discharge of the watergate operation for 2.7 hours during the ebb of CASE1Q and CASE2Q. This will affect sediment transport, and it is predicted to lead to seabed changes. CASE3 is considered to be entering the stabilization stage according to the simulation of the tidal current velocities and directions of the Keum River Estuary and the surrounding coastal area.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.304-313
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• 2018

Agricultural land reclamation in Saemangeum tidal land project is mostly planned to be completed by 2020. Irrigation water for the land is required to be prepared by that time. However, water quality for the irrigation sources is barely meet the target concentration. This paper described the reduction effect of and policy consideration for best management practices (BMPs) which were fertilizer prescription by soil test (SO#1), mixed application of SO#1 and 3 (SO#2), drainage gate control (SO#3), time-release fertilizer application (SO#4), and control (CT). Reduction of paddy runoff was relatively higher in SO#3 (25%) and SO#1 (27%) while lower in SO#4 (9%) and SO#2 (7%) than that in CT. In addition, farmers promised to follow the BMP guidelines but they didn't because of the several problems caused for the BMPs implementation. Thus, it recommended developing an automated control of irrigation gate and paddy water depth and supporing farmers for NPS pollution control and irrigation water reduction.

• Journal of dental hygiene science
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• v.18 no.6
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• pp.374-379
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• 2018

This study attempted to identify factors work environment that affect job satisfaction in dental hygienists. This study was conducted between August 29 and September 28, 2017, as part of an in-depth study of the 'Survey on the Working Environment of Clinical Dental Hygienists' of the Korean Dental Hygienists Association. To get the responses, the questionnaire was posted on the website of the Korean Dental Hygienists Association, and of the respondents, 4,663 were selected and analyzed. An independent t-test and one way ANOVA analysis were used to make a comparison of job satisfaction according to the general characteristics, salary, and tasks. Logistic regression analysis was conducted to identify factors affecting job satisfaction. The significance level was 0.05. In regard to salary information, the job satisfaction was found to be high (p<0.001) in cases where the salary was considered appropriate, when incentives were provided, when rewards or vacation expenses were supported, and when overtime and nightly work allowances were paid. In regard to job information, the job satisfaction was found to be high (p<0.001) when the volume of work was considered appropriate, when there were sufficient numbers in the workforce, and when the division of labor among the other personnel was clear. As a factor affecting job satisfaction of dental hygienists, the case of thinking that 'workload is appropriate' was found to be 2.052 times, showing the highest score. Job satisfaction in dental hygienists affects the turnover and has a significant effect on the performance of the organization. Therefore, it is believed, that it is urgent to improve the working environment such as salary and clear division of duties affecting job satisfaction of dental hygienists.