• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.668-682
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• 2017

Alignments of railways recently constructed in Korea have been straightened due to the advent of high-speed rail, which means increasing the numbers of tunnels and bridges. Overbreak during tunnel construction may be unavoidable, and is very influential on overall stability. Over-excavation in tunneling is also one of the most important factors in construction costs. Overbreak problems around crown areas have decreased with improvements of excavation methods, but overbreak problems around bottom areas have not decreased because those areas are not very influential on tunnel stability compared with crown areas. The filling costs of 10 cm thickness of overbreak at the bottom of a tunnel are covered under construction costs by Korea Railway Authority regulations, but filling costs for more than the covered thickness are considered losses of construction cost. The filling material for overbreak bottoms of tunnels should be concrete, but concrete and mixed granular materials with fractured rock are also used for some sites. Tunnels in which granular materials with fractured rock are used may have a discontinuous section under the concrete slab track. The discontinuous section influences the propagation of waves generated from train operation. When the bottom of a tunnel is filled with only concrete material, the bottom of the tunnel can be considered as a continuous section, in which the waves generated from a train may propagate without reflection waves. However, a discontinuous section filled with mixed granular materials may reflect waves, which can cause resonance of vibration. The filled materials and vibration propagation characteristics are studied in this research. Tunnel bottom filling materials that have ratios of granular material to concrete of 5.0 %, 11.5 %, and 18.0 % are investigated. Samples were made and tested to determine their material properties. Static numerical analyses were performed using the FEM program under train operation load; test results were found to satisfy the stability requirements. However, dynamic analysis results show that some mixed ratios may generate resonance vibration from train operation at certain speeds.

• Journal of the Korean Geotechnical Society
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• v.31 no.11
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• pp.5-13
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• 2015

For the bearing capacity evaluation, dynamic pile tests instead of static pile tests have been commonly used in embedded piles, which are known to have low noise and low vibration construction method. The objective of this study is to analyze the bearing capacity and penetration behaviors of embedded piles, which are constructed in different ground conditions, by using force and velocity signals obtained in the final blows during construction of embedded piles. For the dynamic pile analyses, the CAse Pile Wave Analysis Program (CAPWAP) and Wave Equation Analysis of Piles (WEAP) have been commonly used. In this study, the CAPWAP and WEAP are used for the analyses of the dynamic pile tests, which are conducted on embedded piles. The input values, output values, and force-velocity graphs of CAPWAP determined by analyzing the measured force-velocity signals are investigated. In addition, similar force-velocity singals are obtained from the WEAP by analyzing the input values of the WEAP. Considering the subsurface investigation results around the pile tips, if the N-value increases exponentially along the depth, toe quake value should be small, and therefore large bearing capacity is identified. On the contrary, if the N-value increases linearly, the bearing capacity is small because of large toe quake value. Furthermore, the stiffness of hammer cushion and pile cushion, which is difficult to find correct values, is recommended lower than 500 kN/mm. This study demonstrates that the results of WEAP may be similar to those of CAPWAP and the WEAP can be used to estimate the bearing capacity of embedded piles.

• Journal of The Korean Association For Science Education
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• v.34 no.5
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• pp.499-510
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• 2014

The purpose of this research is to understand interactive learning during docent-led tours in a science museum focusing on scaffolding. We developed a scaffolding framework by collating the work of other researchers in related fields. The results show that scaffolding included three dimensions: purpose, interaction, and domain. The purpose dimension, divided into six categories, is related to the intention of the scaffolder and what the scaffolding are for: strategic, social, procedural, conceptual, verbal, and metacognitive. The interaction dimension reflects students' interaction with the scaffolder in two ways: dynamic (situation specific) and static (planned in advance). The domain dimension is related to two contents: domain-general and domain-specific (such as science). The scaffolding framework was applied to dynamic interactions between docents and visitors. The data was collected from elementary school students' family visits with the guidance of two docents at the Seodaemun Museum of Natural History. The data collected consisted of surveys, interviews, video-recordings, and transcripts. The analysis shows that five guiding contexts and scaffolding phases were recognized; 1) strategic scaffolding in a poorly illustrated exhibit; 2) conceptual scaffolding in a thoroughly explanative exhibit; 3) verbal scaffolding in misleading interpretation; 4) procedural scaffolding in a manipulative exhibit; and 5) metacognitive scaffolding with inaccurate content. In addition, the results show that the docents used the dynamic and static scaffolding synthetically so that the docent-led tour was effective. In conclusion, this study presents the usefulness of understanding visitors' science learning through the scaffolding framework, as well as the how docents can scaffold actively.

• Journal of the Korean Geotechnical Society
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• v.36 no.7
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• pp.15-28
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• 2020

As the skin friction of an embedded pile is produced by the cement paste injected into the borehole, the skin friction cannot be evaluated by the end of initial driving test, which is conducted before the cement paste is cured. In addition, the total resistance of an embedded pile may not be properly evaluated during the restrike test if the base resistance is not fully mobilized because of the insufficient driven energy. The objective of this study is to suggest a new load-settlement curve of embedded piles by combining the results of the end of initial driving and restrike tests. Test piles are installed at fields by using the embedded pile method, and the results of the dynamic pile tests are analyzed using CAse Pile Wave Analysis Program (CAPWAP) after the end of initial driving and restrike tests are conducted. A new load transfer curve, which combines the behaviors of the pile base at the end of initial driving and of the pile shaft at the restrike, is suggested, and a new load-settlement curve is obtained. Subsequently, the resistances of the test piles are evaluated using the combined load-settlement curve, and compared with the results from the end of initial driving and restrike tests. The results showed that the resistances, which are evaluated using the combined load-settlement curve, may overcome the underestimation of the resistance because of the insufficient driven energy. In addition, the resistance resulted from the combined load-settlement curve may be more similar to that from the static load test because the suggested load transfer curve is closer to the behavior of the embedded pile compared to the results of end of initial driving and restrike tests. Therefore, this study demonstrates that the combined load-settlement curve may be effectively used for the evaluation of the bearing capacity of embedded piles.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.3
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• pp.139-148
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• 2000

In this paper, the interaction of oblique incident waves with a bottom-mounted and fluid-filled flexible membrane structure is investigated in the frame of linear hydro-elastic theory. The static shape of a membrane structure containing the fluid of a specific density is initially unknown and must be calculated before the hydrodynamic analysis. To solve hydrodynamic problem, the fluid domain is divided into the inner and outer region. The inner solution based on discrete membrane dynamic model and simple-source distribution over the entire fluid boundaries is matched to the outer solution ba~ed on an eigenfunction expansion method. The numerical results were compared to a series of Ohyama's experimental results. The measured reflection and tran¬smission coefficients reasonably follow the trend of predicted values. Using the computer program developed, the performance of a bottom-mounted and fluid-filled flexible membrane strocture is tested with various system parameters (membrane shape, internal pressure, density ratio) and wave characteristics (wave frequencies, incident wave angle). It is found that a bottom-mounted and fluid-filled flexible membrane structure can be an effel;tive wave barrier if properly designed.

• The Journal of Korean society of community based occupational therapy
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• v.2 no.1
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• pp.25-35
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• 2012

Objective : This study conducted in rural areas, elderly services voucher business and leisure satisfaction survey based on data from the use of community-dwelling older people considering service needs was to find ways to take advantage of leisure time. Methods : Buyeo county residents in this study 71 patients were elderly, the characteristics of elderly gender, the presence of spouse, health status, education level, monthly living expenses, number of children, occupation, and the variables were included. Subjects' self-esteem, life satisfaction, quality of life, program satisfaction questionnaire for the survey were used, t-test and correlation analysis using the correlation between each factor were analyzed. Results : In a survey of participants in leisure activities, TV watching, meeting friends, such as phone calls to static and time-consuming activities were surveyed about satisfaction of the voucher business, the elderly oral health care services, health screening services, sports massage such as health-related services is relatively high degree of satisfaction. Conclusion : The results of this study of elderly people in rural communities through meaningful leisure time were utilized to determine what is lacking, a strong desire for health-related services that could be confirmed. Therefore, further experience and knowledge about activities by providing opportunities for meaningful leisure time needs to improve, and it based on a variety of programs to meet the needs of the elderly should be provided.

• Journal of Convergence for Information Technology
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• v.10 no.5
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• pp.206-215
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• 2020

This study sought to find out the need for NCS education, Education awareness, and class satisfaction among professors and learners of nail art classes based on NCS. From April 21, 2017, to May 31, 2017, the questionnaire of 70 professors and 290 learners using NCS education located in Seoul and Gyeonggi Province was finally analyzed using the SPSS WIN 20.0 program. Analysis result, Professionals have a sense of self-efficiency (r=.466, p<.01), and appropriateness (r=.474, p<.01) has been confirmed. The learners identified static (+) relationships in the necessity of education (r=.338, p<.01), recognition (r=.193, p<.01), and self-efficiency (r=.586, p<.01), and appropriateness (r=.609, p<.01). Through this study, it is believed that NCS education necessity, Education awareness, and class satisfaction of professors and learners can be utilized as basic data.

• The Journal of the Korea Contents Association
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• v.11 no.3
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• pp.281-292
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• 2011

In this study, for examining an effect of lower limbs' muscle activity on balance capability when applying sprinter pattern among the PNF, the experiment was conducted as followed. Under the object of 24 people diagnosed by hemiplegia, they were divided into control group and experimental group and the experiment was conducted on the experimental group, three times per a week for six weeks. Experimental group received Sprinter pattern of combined PNF upper extremity and lower extremity pattern. For the lower limbs' muscle activity, effective values of Vastus medialis laterails, medial lateral hamstrings, lateral gastrocnemius' action potential were analyzed. The balance ability tests was conducted with FICSIT-4, FSST and MTD-Balance system. For the significance test of control group and experimental group for measuring time by exercise application method, two-way repeated measure ANOVA was conducted and for the significance test among the groups by each measuring time, independent t-test was conducted. Also, for examining the correlation among the measuring item, pearson correlation was used for the analysis. As the result, the application of sprinter pattern increased muscle activity of lower limbs in paretic side and improve static and dynamic balance ability effectively. Therefore, it will be necessary to develop new intervention by combining active application of the therapeutic intervention program for lower limbs' effective muscle mobilizing in paretic side with various exercising patterns.

• Journal of Convergence for Information Technology
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• v.10 no.7
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• pp.98-107
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• 2020

Job satisfaction is an important part of social workers who strive to improve the quality of life and independence of their clients. The goal of this study was to reveal the correlation between social workers' self-efficacy, job satisfaction, and supervision to determine whether supervision regulated the effect of social worker's self-efficacy on job satisfaction. In addition, the effect of social worker's self-efficacy on job satisfaction was grasped, and the control effect of supervision regarding the process of social worker's self-efficacy on job satisfaction was identified. For the study, 150 social workers at 10 community welfare centers in Gyeonggi-do and North Seoul area were surveyed, and the statistical program PASW (SPSS) 25.0 was used for data analysis. As a result of the study, it was confirmed that the social worker's self-efficacy had a significant effect on job satisfaction, and that the social worker's self-efficacy had a significant static effect on job satisfaction. In addition, in the process of social worker's self-efficacy affecting job satisfaction, the mediating effect of the supervision function (administrative, educational, and supportive) was found to be significant, so it turned out that the supervision function for social workers was crucial to enhance self-efficacy.

• The Journal of Korean Obstetrics and Gynecology
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• v.18 no.1
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• pp.128-141
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• 2005

Objective : This study was undertaken to investigate the effects of Eucommiae Cortex on the osteoporosis in ovariectomized rats. Materials and Methods : We used Sprague-Dawley female rats in 8-week-old. They were divided into three groups. Sample group was ovariectomized and administered with 10 mg/100 g/day Eucommiae Cortex extract solution for 10 weeks. Control group was ovariectomized and sham group was conducted by sham's operation. And control group and sham group were administered with normal saline as the same way. We measured rats's body and uterus weight and also measured the serum levels of Ca, phosphorus and ALP. We stained the specimens of rat's tibial bones with Goldner's modified Masson's Trichrome and then examined bone histomorphometry with Bioquant computer program of image analysis system. We measured the thickness of osteoid and callus as static parameters and measured bone volume and mineral apposition rate as dynamic parameters. We observed the expressions of RANKL and OPG mRNA of the tibial bone by RT-PCR. Results : The body weight was significantly (p<0.05) increased in control and sample groups compared with sham group, respectively. The uterus weight was significantly (p<0.05) decreased in control and sample group compared with sham group. In the change of Ca, phosphorus and ALP there were no significant changes among three groups. There were no significant changes of trabecula cortical and osteoid bones' thickness and volume. But trabecula mineral apposition rate (MAR) was significantly (p<0.05) increased in sham and sample group compared with control group. In the expression of RANKL mRNA, sample group was decreased compared with control group, and in that of OPG mRNA, sample group was increased compared with control group. Conclusion : This study shows that Eucommiae Cortex has the beneficial effects on bone histomorphometry and metabolism in the ovariectomized rats. We suggest that Eucommiae Cortex be useful for the treatment of osteoporosis.