• Title/Summary/Keyword: Fill

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A Methodology for Quality Control of Railroad Trackbed Fills Using Compressional Wave Velocities : I. Preliminary Investigation (압축파 속도를 이용한 철도 토공노반의 품질관리 방안 : I. 예비연구)

  • Park, Chul-Soo;Mok, Young-Jin;Choi, Chan-Yong;Lee, Tai-Hee
    • Journal of the Korean Geotechnical Society
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    • v.25 no.9
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    • pp.45-55
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    • 2009
  • The quality of railroad trackbed fills has been controlled by field measurements of density and bearing resistance of plate-load tests. The control measures are compatible with the design procedures whose design parameter is $k_{30}$ for both ordinary-speed railways and high-speed railways. However, one of fatal flaws of the design procedures is that there are no simple laboratory measurement procedures for the design parameters ($k_{30}$ or, $E_{v2}$ and $E_{v2}/E_{v1}$) in design stage. To overcome the defect, the compressional wave velocity was adopted as a control measure, in parallel with the advent of the new design procedure, and its measurement technique was proposed in the preliminary investigation. The key concept of the quality control procedure is that the target value for field compaction control is the compressional wave velocity determined at optimum moisture content using modified compaction test, and direct-arrival method is used for the field measurements during construction, which is simple and reliable enough for practice engineers to access. This direct-arrival method is well-suited for such a shallow and homogeneous fill lift in terms of applicability and cost effectiveness. The sensitivity of direct-arrival test results according to the compaction quality was demonstrated at a test site, and it was concluded that compressional wave velocity can be effectively used as quality control measure. The experimental background far the companion study (Park et al., 2009) was established through field and laboratory measurements of the compressional wave velocity.

Characteristics of Deformation and Shear Strength of Parallel Grading Coarse-grained Materials Using Large Triaxial Test Equipment (대형삼축시험에 의한 상사입도 조립재료의 변형 및 전단강도 특성)

  • Jin, Guang-Ri;Snin, Dong-Hoon;Im, Eun-Sang;Kim, Ki-Young
    • Journal of the Korean Geotechnical Society
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    • v.25 no.12
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    • pp.57-67
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    • 2009
  • Along with the advanced construction technologies, the maximum size of coarse aggregate used for dam construction ranges from several cm to 1m. Testing the original gradation samples is not only expensive but also causes many technical difficulties. Generally, indoor tests are performed on the samples with the parallel grading method after which the results are applied to the design and interpretation of the actual geotechnical structure. In order to anticipate the exact behavior characteristics for the geotechnical structure, it is necessary to understand the changes in the shear behavior. In this study, the Large Triaxial Test was performed on the parallel grading method samples that were restructured with river bed sand-gravel, with a different maximum size, which is the material that was used to construct Dam B in Korea. And the Stress - Strain characteristics of the parallel grading method samples and the characteristics of the shear strength were compared and analyzed. In the test results, the coarse-grained showed strain softening and expansion behavior of the volume, which became more obvious as the maximum size increased. The internal angle of friction and the shear strength appeared to increase as the maximum size of the parallel grading method sample increased.

Performance of IPS Earth Retention System in Soft Clay (연약지반에 적용된 IPS 흙막이 시스템의 거동 특성)

  • Kim, Nak-Kyung;Park, Jong-Sik;Oh, Hee-Jin;Han, Man-Yop;Kim, Moon-Young;Kim, Sung-Bo
    • Journal of the Korean Geotechnical Society
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    • v.23 no.3
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    • pp.5-13
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    • 2007
  • The performance of innovative prestressed support (IPS) earth retention system applied in soft clay was investigated and presented. The IPS wale system provides a high flexural stiffness to resist the bending by lateral earth pressure, and transfers lateral earth pressure to strut supports. The IPS wale system provides a larger spacing of support than conventional braced and anchored systems. The IPS earth retention system was selected for temporary earth support in a building construction in North Busan area. The excavation was made 28.8 m wide, 52.0 m long, and 16.1 m deep through loose fill to soft clay. The IPS system consists of 650 mm thick slurry walls, and five levels of IPS wales and struts. Field monitoring data were collected including wall deflections at six locations, ground water levels at four locations, IPS wale deflections at thirty locations, and axial loads on struts at twenty locations, during construction. The IPS earth retention system applied in soft clay performed successfully within a designed criterion. Field measurements were compared with design assumptions of the IPS earth retention system. The applicability and stability of the IPS earth retention system in soft clay were investigated and evaluated.

Development and Verification of Large Triaxial Testing System for Dynamic Properties of Granular Materials (조립재료 동적물성 산정을 위한 대형삼축압축시험장비 구축 및 검증)

  • Lee, Sung-Jin;Kim, Yun-Ki;Choo, Yun-Wook;Lee, Sei-Hyun;Kang, Tae-Ho
    • Journal of the Korean Geotechnical Society
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    • v.26 no.12
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    • pp.5-17
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    • 2010
  • Coarse granular material is used as important fill material in most of large embankments such as railway, road, dam and so on. Therefore, the accurate design parameters of the coarse granular material are necessarily required in design and construction. The behavior of the coarse granular material was not well understood because of the lack of large testing equipment capable of coarse granular material. A large triaxial testing system was developed in this research, capable of large specimens of 500 mm, 300 mm and 150 mm in diameter. In the new large triaxial testing system, the load cell is installed inside the triaxial cell and axial displacement is measured locally on a specimen in order to improve control and measurement in small strain level. Urethane specimens of 300 mm and 50 mm in diameter were prepared. The large triaxial tests were performed on the 300 mm diameter urethane specimens while RC/TS and impact echo tests on the 50 mm diameter urethane specimens to verify this testing system. In this verification test results, we could ascertain the reasonable test results of the KRRI large triaxial testing system.

A Study on the Relationship between Self-Determination Motivation, Exercise Satisfaction, and Exercise Continuation Intention in High School Students (고등학생의 자기결정성 동기, 운동만족, 운동지속의도의 관계)

  • Young-Jin Choi;Se-Hee Choi
    • Journal of the Korean Applied Science and Technology
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    • v.40 no.2
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    • pp.233-243
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    • 2023
  • The purpose of this study is to analyze the relationship between self-determination motivation of high school students on exercise satisfaction and exercise continuation intention. To this end, as of March 2022, an online questionnaire was distributed to 440 male students attending high schools in Seoul and Gyeonggi Province, and they were asked to fill out the questionnaire through self-assessment. 346 copies were selected as a valid sample, excluding 94 copies of insincere responses such as responses of the same pattern and incomplete responses. For data processing, frequency analysis, confirmatory factor analysis, and correlation analysis were conducted using SPSS 24.0 and IBM AMOS 18.0 statistical programs, and the following results were derived through structural equation model analysis to identify the structural relationship between factors. First, among self-determination motivation factors, competence and relatedness had a positive (+) effect on exercise satisfaction, but autonomy had a negative (-) effect on exercise satisfaction. Second, there was no relationship between self-determination motivation and exercise continuation intention in high school students. Third, it was found that the relationship between exercise satisfaction and exercise continuation intention had a positive (+) effect.

Cross-sectional perception studies of children's monosyllabic word by naive listeners (일반 청자의 아동 발화 단음절에 대한 교차 지각 분석)

  • Ha, Seunghee;So, Jungmin;Yoon, Tae-Jin
    • Phonetics and Speech Sciences
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    • v.14 no.1
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    • pp.21-28
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    • 2022
  • Previous studies have provided important findings on children's speech production development. They have revealed that essentially all aspects of children's speech shift toward adult-like characteristics over time. Nevertheless, few studies have examined the perceptual aspects of children's speech tokens, as perceived by naive adult listeners. To fill the gap between children's production and adults' perception, we conducted cross-sectional perceptual studies of monosyllabic words produced by children aged two to six years. Monosyllabic words in the consonant-vowel-consonant form were extracted from children's speech samples and presented aurally to five listener groups (20 listeners in total). Generally, the agreement rate between children's production of target words and adult listeners' responses increases with age. The perceptual responses to tokens produced by two-year old children induced the largest discrepancies and the responses to words produced by six years olds agreed the most. Further analyses were conducted to identify the sources of disagreement, including the types of segments and syllable structure. This study makes an important contribution to our understanding of the development and perception of children's speech across age groups.

Impact of Franchisor Leadership and Franchisee Marketing Efforts on Franchisee Dissatisfaction and Switching Intentions (프랜차이즈 가맹본부 리더십과 가맹점 마케팅 노력이 가맹점 불만족과 전환의도에 미치는 영향)

  • Han, In-Su;Lee, Phil-Soo;Park, Heung-Jin
    • The Korean Journal of Franchise Management
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    • v.7 no.1
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    • pp.31-44
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    • 2016
  • Purpose - This study aims to examine different impacts of franchisor's leadership and franchisee's marketing efforts on franchisee dissatisfaction and switching intentions, and to investigate how franchisee dissatisfaction plays a mediating role in the relationship between these constructs. This study attempted to fill the gap in the literature by treating the franchisee dissatisfaction as a mediator in the relationship between these constructs, identify how franchisor's leadership and franchisee's marketing efforts have effects on franchisee dissatisfaction, in turn, reduce switching intentions, and provide the managerial implications for building a long-term relationship to achieve mutual goals between franchisors and franchisees Research design, data, and methodology - In order to test the hypotheses, the data were collected from franchisees in Seoul and Gyeonggi Province. The franchisee owners were informed about the purpose of this study by the trained interviewers. The respondents received a letter introducing the purpose of this study and another letter that the owners wrote to encourage their active participation. Among the 300 questionnaires distributed, 260 (86.7%) questionnaires were returned. Of those collected questionnaires, 6 uncompleted responses were excluded, and 254 questionnaires with an effective response rate of 84.7% were coded and analyzed using frequency, confirmatory factor analysis, and correlations analysis, and structural equation modeling with SPSS 21.0 and SmartPLS 3.0. Results - The findings of the study are as follows. First, franchisor leadership had a negative effect on franchisee dissatisfaction, but franchisee marketing efforts did not have a significant effect on franchisee dissatisfaction. Second, franchisee dissatisfaction had a positive effect on switching intentions. Third, franchisor leadership had a negative effect on switching intentions, but franchisee marketing efforts did not have a significant effect on switching intentions. Conclusions - This study researched the franchisor's leadership as a single factor of transformational leadership. Thus, it may have limits in measuring leadership. Future studies shall include emotional, loyal, and transactional leadership. In addition, the future studies shall also research the effect of franchisor's leadership and franchisees' marketing efforts on dissatisfaction and switching intentions. For example, the franchisor's relationship-oriented efforts can be a crucial parameter that reduces dissatisfaction and switching intentions.

Experimental Analysis of Large Size Concrete-Filled Glass Fiber Reinforced Composite Piles Subjected to the Flexural Compression (대구경 콘크리트 충전 복합소재 파일의 휨-압축 거동에 대한 실험적 분석)

  • Lee, Sung Woo;Choi, Sokhwan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.5A
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    • pp.519-529
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    • 2009
  • Fiber reinforced composite materials have various advantages in mechanical and chemical aspects. Not only high fatigue and chemical resistance, but also high specific strength and stiffness are attained, and therefore, damping characteristics are beneficial to marine piles. Since piles used for marine structures are subjected to compression and bending as well, detailed research is necessary. Current study examine the mechanical behavior under flexural and/or compressive loads using concrete filled fiber reinforced plastic composite piles, which include large size diameter. 25 pile specimens which have various size of diameters and lengths were fabricated using hand lay-up or filament winding method to see the effect of fabrication method. The inner diameters of test specimens ranged from 165 mm to 600 mm, and the lengths of test specimens ranged from 1,350 mm to 8,000 mm. The strengths of the fill-in concrete were 27 and 40 MPa. Fiber volumes used in circumferential and axial directions are varied in order to see the difference. For some tubes, spiral inner grooves were fabricated to reduce shear deformation between concrete and tube. It was observed that the piles made using filament winding method showed higher flexural stiffness than those made using hand lay-up. The flexural stiffness of piles decreases from the early loading stage, and this phenomenon does not disappear even when the inner spiral grooves were introduced. It means that the relative shear deformation between the concrete and tube wasn't able to be removed.

Living Arrangements and Psychological Distress among Older Korean Immigrants and older Koreans (미주한인 노인이민자와 한국노인의 동거형태와 심리적 고통에 관한 연구)

  • Chang, Miya
    • 한국노년학
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    • v.39 no.3
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    • pp.635-652
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    • 2019
  • A few studies have examined the relationship between living arrangements and mental health status among older Korean immigrants in the United States and older Koreans in South Korea. This study attempts to fill this gap by conducting a comparative study to understand the relationship between living arrangements and psychological distress. Survey data from older Koreans between the ages of 60 and 79 from the two countries (N= 480) was analyzed descriptively and in hierarchical multiple regressions. This study found that among older Korean immigrants in the United States 26.4 % of those living alone and 7.3 % of those living with a spouse only reported 'severe' psychological distress while their counterparts in South Korea 20.0 % of those living alone and 20.6 % of those living with a spouse only reported 'severe' psychological distress. The hierarchical multivariate analysis reveled that older Koreans living alone are not significant predictor of psychological distress in both countries. Interestingly, older Korean immigrants living with a spouse only and living with others are significant predictors of psychological distress. This study also contributes to the existing literature by searching for diverse conditions that lead to mental health problems among older Koreans in both countries.

A New Challenge to Korean American Religious Identity: Cultural Crisis in Korean American Christianity

  • Ro, Young-Chan
    • Journal of the Daesoon Academy of Sciences
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    • v.18
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    • pp.53-79
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    • 2004
  • This paper explores the relationship between Korean immigrants to the United States and their religious identity from the cultural point of view. Most scholarly studies on Korean immigrants in the United States have been dominated by sociological approach and ethnic studies in examining the social dimension of the Korean immigrant communities while neglecting issues concerning their religious identity and cultural heritage. Most Korean immigrants to America attend Korean churches regardless their religious affiliation before they came to America. One of the reasons for this phenomenon is the fact that Korean church has provided a necessary social service for the newly arrived immigrants. Korean churches have been able to play a key role in the life of Korean immigrants. Korean immigrants, however, have shown a unique aspect regarding their religious identity compared to other immigrants communities in the United States. America is a nation of immigrants, coming from different parts of the world. Each immigrant community has brought their unique cultural heritage and religious persuasion. Asian immigrants, for example, brought their own traditional religions such as Hinduism, Buddhism. People from the Middle Eastern countries brought Islamic faith while European Jews brought the Jewish tradition. In these immigrant communities, religious identity and cultural heritage were homo genously harmonized. Jewish people built synagogue and taught Hebrew, Jewish history, culture, and faith. In this case, synagogue was not only the house of worship for Jews but also the center for learning Jewish history, culture, faith, and language. In short, Jewish cultural history was intimately related to Jewish religious history; for Jewish immigrants, learning their social and political history was indeed identical with leaning of their religious history. The same can be said about the relationship between Indian community and Hinduism. Hindu temples serve as the center of Indian immigrantsin providing the social, cultural, and spiritual functions. Buddhist temples, for that matter, serve the same function to the people from the Asian countries. Chinese, Japanese, Vietnamese, Tibetans, and Thais have brought their respective Buddhist traditions to America and practice and maintain both their religious faith and cultural heritage. Middle Eastern people, for example, have brought Islamic faith to the United States, and Mosques have become the center for learning their language, practicing their faith, and maintaining their cultural heritage. Korean immigrants, unlike any other immigrant group, have brought Christianity, which is not a Korean traditional religion but a Western religion they received in 18th and 19th centuries from the West and America, back to the United States, and church has become the center of their lives in America. In this context, Koreans and Korean-Americans have a unique situation in which they practice Christianity as their religion but try to maintain their non-Christian cultural heritage. For the Korean immigrants, their religious identity and cultural identity are not the same. Although Korean church so far has provides the social and religious functions to fill the need of Korean immigrants, but it may not be able to become the most effective institution to provide and maintain Korean cultural heritage. In this respect, Korean churches must be able to open to traditional Korean religions or the religions of Korean origin to cultivate and nurture Korean cultural heritage.

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