• Title/Summary/Keyword: Failure capacity

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A Study on the Flexural Capacity of Reinforced Timber Beams with the Inserting Method of CFRP Plates (탄소섬유판 삽입공법으로 보강된 목재보 휨강도에 관한 연구)

  • Kwon, Ki-Hyuk;Yu, Hye-Ran;Lee, Jin-Hyuk;Choi, Min-Seok
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.1
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    • pp.1-7
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    • 2008
  • When historical or cultural buildings need to be repaired or reinforced, the changes of original features should be minimized, and the strengths of structures should be improved. Among the existing methods to reinforce historical wood structures, the carbon fiber reinforcement polymer (CFRP) installation method is one of the best ones to achieve the afore-mentioned requirements. Therefore, this study aims at investigating the reinforcing effects and failure modes of timber beams reinforced with the inserted CFRP, a part of roof trusses in modern wood structures, and at providing the fundamental test data to estimate the CFRP rein-forced timber beam in the application of this reinforcing method. The primary parameters in this study were the layout and amount of CFRP. It was observed that, when $0.3{\sim}0.7%$ of CFRP were installed, the strengths of reinforced timber beams increased up to 173% compared to its original strength, but their strengthening effects were heavily influenced by the characteristics of timber such as burls. In order to improve the applicability of this strengthening method, fundamental understandings on the characteristics of wood would be necessary, and there would be in need of researches on the non-destructive test for wood structures as well.

Mesenchymal Stem Cells Ameliorate Adriamycin Induced Proteinuric Nephropathy (Adriamycin 유발 신병증에서 중간엽 줄기세포의 완화 효과)

  • Kang, Hee-Gyung;Park, So-Yeon;Ha, Il-Soo;Cheong, Hae-Il;Choi, Yong
    • Childhood Kidney Diseases
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    • v.14 no.1
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    • pp.32-41
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    • 2010
  • Purpose : Glomerulonephropathy (GN) often manifests as proteinuria and progresses to chronic renal failure without specific therapy. Mesenchymal stem cell (MSC) has been tried as a therapeutic agent in experimental GN, and previous studies showed that administration of MSC concomitantly to the insult inducing GN or via intra-renal administration ameliorated proteinuria. The purpose of this study was to test the therapeutic potential of MSC administered via intravenous route at the time of clinically evident proteinuria. Methods : MSCs were administered intravenously via tail vain into the mice with adriamycin (ADR) induced nephropathy (ADR-GN), two weeks after ADR injection when massive proteinuria was evident. To test the capacity of MSC modulate the cytokine production in the inflammatory milieu, the concentrations of IFN-$\gamma$ and IL-10 were measured in the supernatant of in vitro mixed lymphocyte culture (MLC) with or without additional MSC. Results : MSCs administered intravenously into the proteinuric mice with ADR-GN accelerated the recovery of this experimental GN with disappearance of proteinuria in two weeks when the saline treated (control) mice still showed significant proteinuria. The mice treated with MSC also had a tendency of better survival. Addition of MSC decreased IFN-$\gamma$ and increased IL-10 in the supernatant of MLC. Conclusion : This study showed that MSC had a therapeutic potential even when administered in a more clinically relevant setting into a proteinuric glomerulonephropathy model. Further study to verify the mechanism and long-term safety of this phenomenon is required.

China's Economic Slow-down and the Middle-Income Trap Controversy (중국의 저성장과 '중진국함정론'에 근거한 위기요인 분석)

  • Kim, Eui-Dong
    • International Area Studies Review
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    • v.20 no.2
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    • pp.113-140
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    • 2016
  • This paper first extracts the main basis for the Middle-Income Trap(MIT) to apply these grounds to reality of the Chinese economy. And then confirmed crisis factors of China economy. Also discussed then the economic reforms of China in order to not fall into the MIT. After reviewing previous research extracted six factors the results will correspond to comply with the Chinese economy. Those are 'Over-investment', 'excess capacity' 'reduction of TFP continued,' 'disappearance and the aging of the population bonus', 'excessive debt and structural adjustment and financial instability of the company', 'income unequal expansion', 'low financial and information infrastructure accessibility', and 'low transparency index'. China's policy direction to avoid the MIT generally set properly, but proof that implementation process not easy, was appearing everywhere. After all, China economy should be modified now to a reforms of 'government failure' and promotion of function for ongoing restructuring system in the market. Because of the SDR incorporation from 2015, it is inevitable to face major constraints in the external aspects.

Bond Behavior of Epoxy Coated Reinforcement Using Direct Pull-out Test and Beam-End Test (직접인발시험과 보-단부 시험을 이용한 에폭시 도막 철근의 부착특성)

  • Kim, Jee-Sang;Kang, Won Hyeak
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.3
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    • pp.271-278
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    • 2019
  • The corrosion of reinforcements embedded in concrete causes severe deterioration in reinforced concrete structures. As a countermeasure, epoxy coated reinforcements are used to prevent corrosion of reinforcements. When epoxy coated bars are used, the resistance of corrosion is excellent, but epoxy coating on the bars have a disadvantage of reduction in bond capacity comparing to that of normal bars. Therefore, it is necessary to confirm the bond performance of epoxy coated reinforcements through experimental and analytical methods. Bond behaviors of epoxy coated bars for various diameters of 13 and 19mm and thicknesses of cover concrete of 3 types(ratio of cover to bar diameter) are examined. As the diameters of the epoxy coated bars increase, the difference of bond strength between epoxy coated and uncoated bars also increases and damage patterns showed pull out failure. In addition, finite element analysis was performed based on the bond-slip relationship obtained by direct pullout test and compared with the flexural test results. It is considered that flexural member test is more useful than pullout test for simulating the behavior of actual structure.

A Study on the Analysis of Monitoring Settlement Considering the History of the Groundwater Level in the Dredged Landfill Area Affected by Algae (조류의 영향을 받는 준설매립지역에서 지하수위 이력을 고려한 계측침하 분석에 관한 연구)

  • Jang, Ji-Gun;Son, Su-Won;Hong, Seok-Woo
    • Journal of the Korean Geotechnical Society
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    • v.37 no.7
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    • pp.13-23
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    • 2021
  • If roads, bridges, buildings, etc. are built on the ground with soft clay or organic soil, there may be a lot of problems in geotechnical engineering such as settlement and stability due to the large settlement and lack of bearing capacity. In extreme cases, it may appear due to shear failure or collapse of the constructed structure, so a ground improvement method is indispensable to increase the strength of the ground and to suppress settlement. In this study, the settlement according to each groundwater level condition was analyzed using the measurement results for the groundwater level conditions, one of the important factors in predicting the settlement in dredged and reclaimed ground, and the groundwater level conditions applied to the settlement analysis were proposed by comparing it with settlement generated 5 years after construction. As a result of the analysis, it is judged that it is reasonable to apply the measured groundwater level during construction and the low water ordinary neap tide (L.W.O.N.T) during load application for the groundwater level in the settlement analysis. In addition, in the case of the dredged and reclaimed ground, it is estimated that the water pressure acting on the clay layer is nonlinear, as the result of the observations of the head of water at the observation points above and below the in-situ clay layer were different.

A Study on the Automation of MVDC System-Linked Digital Substation (MVDC 시스템연계 디지털변전소 자동화 연구)

  • Jang, Soon Ho;Koo, Ja Ik;Mun, Cho Rong
    • KIPS Transactions on Computer and Communication Systems
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    • v.10 no.7
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    • pp.199-204
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    • 2021
  • Digital substation refers to a substation that digitizes functions and communication methods of power facilities such as monitoring, measuring, control, protection, and operation based on IEC 61850, an international standard for the purpose of intelligent power grids. Based on the intelligent operating system, efficient monitoring and control of power facilities is possible, and automatic recovery function and remote control are possible in the event of an accident, enabling rapid power failure recovery. With the development of digital technology and the expansion of the introduction of eco-friendly renewable energy and electric vehicles, the spread of direct current distribution systems is expected to expand. MVDC is a system that utilizes direct current lines with voltage levels and transmission capacities between HVDCs applied to conventional transmission systems and LVDCs from consumers. Converting existing lines in substations, where most power equipment is alternating current centric, to direct current lines will reduce transmission losses and ensure greater current capacity. The process bus of a digital substation is a communication network consisting of communication equipment such as Ethernet switches that connect installed devices between bay level and process level. For MVDC linkage to existing digital substations, the process level was divided into two buses: AC and DC, and a system that can be comprehensively managed in conjunction with diagnostic IEDs as well as surveillance and control was proposed.

Case study of dramatherapy for a bulmina nervosa patient (폭식증 환자의 연극치료 사례)

  • Lee, Hyowon
    • Journal of Korean Theatre Studies Association
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    • no.52
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    • pp.359-397
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    • 2014
  • This paper describes dramatherapy with a bulmina nervosa patient. She was in her early 20s and has been under the various psychotherapies for cure of deep depression since 2005. We had 24 sessions and 3 persons - the patient, the therapist, and the assist-therapist- participated in dramatherapy. I found there's a big collision between her important roles in the course of initial interview and diagnosis. Those roles are 'a good daughter of mom' and 'an independent adult'. Therefore I defined her bulmina nervosa as 'an symbolic behavior repeats compulsively the failure of separation from her mother.' And I set the general goals, the separation from her mother, the awareness and expression of negative emotions, and the diminuation of overeating and vomiting. To attain these object, we had many different dramatic experiences in dramatherapy. We made a self-portrait, the mask of bulmina nervosa, family sculpture, figure work, the past I and the present I, psychodramatic scene and several stories. In order to objective assessment, I used behavioral observation and 6PSM(6 Pieces Story Making) analysis. First of all the most noticeable change was a rapid decrease in over-eating and vomiting. Before the dramatherapy she had overeaten 30 times per week. At the closure it has fallen off to 1 time per week. Another behavioral changes were shift of outward appearance, not going church, working for living, and having a date with only one. She made 3 stories on 1th session, 13th session, and 23th session. And I comparatively analysed those stories with both qualitative and quantitative method. For qualitative analysis, I classified 5 structures according to the substantial similrarity. On protagonist structure, there's no difference. Three protagonists are dead things. The type of task structure is changed from an escape, a traveling, to metamorphosis. The type of obstruction structure is changed from the protagonist to an outside object. The type of closure structure is changed from an exaggerated happy ending, sad ending to probable happy ending. To quantitify the aspects of transformation, I developed an assesment tool using likert scale. It is composed of 4 sub-categories-reality testing, imagination, ego-strength, optimism problem-solving. In reality testing category, a shift of score was 9-11-15, imagination 2-5-5, ego strength 3-2-2, optimism 6-3-7, and total score 20-21-29. This change of score reflects the growth of problem solving capacity. Viewed in this light, dramatherapy with this girl was successful on the whole. The thing had significant effect on it was psycho-dynamic approach focused on separation from her mother and defence mechanism to avoid negative emotion. And assessment method used in this case will be full of suggestions to researches to come.

The Effects of Entrepreneur Competence Characteristics on Start-Up Performance: Focusing on the Mediating Effect of the Start-Up Support System (창업가 역량 특성이 창업성과에 미치는 영향에 관한 연구: 창업지원제도 매개효과 중심으로)

  • Ahn, Tae-Uk;Han, Dong-heuy;Kang, Tae-Won
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.14 no.1
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    • pp.73-83
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    • 2019
  • As the awareness of the importance of Start-up increases, the number of entrepreneurs who decide to start their career is gradually increasing. However, the rate of start-up failure is still high and the qualitative level is very low due to lack of start-up performance. In this study, we analyzed the effect of entrepreneurship capability and start-up support system on start-up performance. To that end, 361 valid data were collected from businesses that were established less than seven years ago in Jeollabuk-do on August 1, 2018 and used for study verification through SPSS 21 and AMOS 21. First, the entrepreneurial competence (entrepreneurial competence, managerial competency) has a positive effect on the start-up support system and the technical competency has no significant effect. Second, entrepreneurial competence (entrepreneurial competence, managerial competency, technical competency) has a significant effect on entrepreneurial performance. However, entrepreneurial competence has a meaningful effect on the start-up performance of entrepreneurs with a negative (-) effect. Third, it was found that the start - up support system had a positive effect on the start - up performance. Finally, the start - up support system proved to have mediating effect between entrepreneurial competence and start - up performance. The implications of this study are as follows. In order to increase the start-up performance of the start-up companies, it is proved that increasing the capacity of the start-ups is an important factor. In addition, empirical studies have proved that the use of start-up support system is an important factor that directly or indirectly has a significant effect on start-up performance, We have made meaningful implications that actively supporting and utilizing entrepreneurship is necessary to enhance start-up performance.

A Case Study on Earthquake-induced Deformation of Quay Wall and Backfill in Pohang by 2D-Effective Stress Analysis (2차원 유효응력 해석에 의한 지진시 포항 안벽구조물의 변형 사례 분석)

  • Kim, Seungjong;Hwang, Woong-Ki;Kim, Tae-Hyung;Kang, Gi-Chun
    • Journal of the Korean Geotechnical Society
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    • v.35 no.7
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    • pp.15-27
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    • 2019
  • The purpose of this study is to investigate the mechanism about damages occurring at quay wall and backfill in Youngilman Port during Pohang earthquake (M5.4) on November 15, 2017. In the field investigation, the horizontal displacement of the caisson occurred between 5 cm and 15 cm, and the settlement at backfill occurred higher than 10 cm. 2D-effective Stress Analysis was performed to clarify the mechanism for the damage. The input earthquake motion used acceleration ($3.25m/s^2$) measured at bedrock of Pohang habor. Based on a numerical analysis, it was found that the effective stress decreased due to the increase of excess pore pressure in the backfill ground and the horizontal displacement of the caisson occurred by about 14 cm, and the settlement occurred by about 3 cm. In backfill, the settlements occurred between 6 cm and 9 cm. This is similar to field investigation results. Also, it was found that the backfill soil was close to the Mohr-Coulomb failure line due to the cyclic loading from the effective stress path and the stress-strain behavior. It may be related to decreasing of bearing capacity induced by the reduction of effective stress caused by the increase of the excess pore water pressure.

Exploring the Transnational Mobility and Work Experience of Young Koreans in Singapore (초국적 이동성과 일 경험: 한국 청년들의 싱가포르 해외취업 사례 연구)

  • YUK, Joowon
    • The Southeast Asian review
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    • v.28 no.3
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    • pp.111-158
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    • 2018
  • This paper pays attention to the recent increase of young Koreans working in the low-skilled service sector in Singapore. Such rapid increase largely results from the Korean government's initiatives to promote labour migration of young people and the concurrent proliferation of migration agencies, against the background of growing youth unemployment in South Korea. By exploring the motivations and trajectories of young people's labour migration to Singapore, this study examines to what extent they think their expectations have been met and how they interpret their migration and work experiences. There has been little research that examines the actual voices of young migrants as part of migration studies, whilst the majority of previous research focuses on the evaluation of government support programmes based on job matching rates, surveys of participant satisfaction and etc. Young people who went to Singapore to improve their English language skills and qualifications for future employment in Korea have become frustrated due to low-skilled service jobs that consist of low pay and high labour intensity. Their credentials are devalued and they experience deskilling through this migration process. Most of them were discontent with the Korean migration agencies they used and critical about programmes offered by government institutions and universities/colleges. Despite being subject to deskilling, they did try to actively cope or resist this situation. This study focuses on the various ways these migrants attempted to manage the gap between their initial expectations and reality. It also demonstrates how these migrants interpreted their work experiences after returning to Korea: whilst most of them did not cash off their Singapore work experience for a decent job after returning to Korea, they did not define their experience as a complete failure. Adding to cultural, social capital they gained through this experience, they acquired 'mobility capital' which includes confidence, the desire to move, and capacity to control one's own movement.