• Title/Summary/Keyword: 강도한계

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The Effect of Rainfall on the Stability of Mudstone Slope in Consideration of Collapse Record (이암 절취사면의 붕괴이력을 고려한 강우침투에 따른 안정성 분석)

  • Jeon, Byeong-Chu;Lee, Su-Gon;Kim, Young-Muk;Chung, Sung-Rae
    • Journal of the Korean Geotechnical Society
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    • v.25 no.2
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    • pp.55-66
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    • 2009
  • At the mudstone slope located on the roadside of the Seokri area in Donghae-myeon, Pohang, Gyeongsangbuk-do, this study was performed to analyze the effects of rainfall on the stability of slope through seepage analysis according to the precipitation type of the mudstone slope, referring to the actual case of slope failure. For this, precise geological survey, geophysical exploration and drilling survey for the slope where the failure occurred were performed and followed by analysis of detailed soil layer. For the section where failure surface located, the durability reduction of rocks was measured through slaking/swelling tests and the permeability was measured through in-situ permeability tests for each soil layer. In addition, the change of strength parameter and process of instability were analyzed by back analysis, using Talren 97 and Slope/W programs, in the slope. By applying different precipitation conditions to the geographical conditions of the slope that had actual failure records, the slope stability was analyzed by seepage analysis according to duration of rainfall and rise of groundwater level resulting from the flow of rainfall caused by development of geological structures and the slope surface condition.

District-Level Seismic Vulnerability Rating and Risk Level Based-Density Analysis of Buildings through Comparative Analysis of Machine Learning and Statistical Analysis Techniques in Seoul (머신러닝과 통계분석 기법의 비교분석을 통한 건물에 대한 서울시 구별 지진취약도 등급화 및 위험건물 밀도분석)

  • Sang-Bin Kim;Seong H. Kim;Dae-Hyeon Kim
    • Journal of Industrial Convergence
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    • v.21 no.7
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    • pp.29-39
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    • 2023
  • In the recent period, there have been numerous earthquakes both domestically and internationally, and buildings in South Korea are particularly vulnerable to seismic design and earthquake damage. Therefore, the objective of this study is to discover an effective method for assessing the seismic vulnerability of buildings and conducting a density analysis of high-risk structures. The aim is to model this approach and validate it using data from pilot area(Seoul). To achieve this, two modeling techniques were employed, of which the predictive accuracy of the statistical analysis technique was 87%. Among the machine learning techniques, Random Forest Model exhibited the highest predictive accuracy, and the accuracy of the model on the Test Set was determined to be 97.1%. As a result of the analysis, the district rating revealed that Gwangjin-gu and Songpa-gu were relatively at higher risk, and the density analysis of at-risk buildings predicted that Seocho-gu, Gwanak-gu, and Gangseo-gu were relatively at higher risk. Finally, the result of the statistical analysis technique was predicted as more dangerous than those of the machine learning technique. However, considering that about 18.9% of the buildings in Seoul are designed to withstand the Seismic intensity of 6.5 (MMI), which is the standard for seismic-resistant design in South Korea, the result of the machine learning technique was predicted to be more accurate. The current research is limited in that it only considers buildings without taking into account factors such as population density, police stations, and fire stations. Considering these limitations in future studies would lead to more comprehensive and valuable research.

Evaluation on Laboratory Moisture Damage Characteristics of the Asphalt Mixtures using Indirect Tensile Test (간접인장시험을 이용한 아스팔트 혼합물의 실내 수분손상 특성 평가)

  • Hwang, Sung Do;Rhee, Suk Keun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.2D
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    • pp.243-248
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    • 2008
  • Moisture damage of asphalt pavements can usually occur because of the loss of adhesion and cohesion between the asphalt binder and aggregate in the asphalt mixture due to presence of water. And this is one of the causes that is effect on the main distress of asphalt pavement. The objective of this study is to find out moisture damage characteristics of asphalt pavement. Effects of this study changes of the material properties and resistance characteristics of moisture damage on the asphalt mixtures under various temperatures and repeated immersion using indirect tensile test and modify Lottman test were evaluated during this study. The asphalt mixtures were produced using straight asphalt binder, SBS modified asphalt binder and aggregates. The material properties (resilient modulus, indirect tensile strength, failure energy and $DCSE_f$) of the asphalt mixtures were generally decreased with increasing to moisture damage caused by the number of repeated immersion. The decrease ratios of material properties by repeated immersion on SBS modified asphalt mixtures were lower than those of straight asphalt mixtures at all three test temperatures. As a conclusion, current criterion for evaluation moisture damage of asphalt mixtures is difficult for using distinction standard because of the limited evaluation criterion with one time immersion and single material property. Based on this research, to evaluate long term moisture damage on asphalt mixtures, material property tests of various kinds with repeated immersion test are considered.

Looking into Child-rearing Experience of Mothers from Multicultural Families through the Grounded Theory Paradigm Model (근거이론 패러다임 모형으로 다문화가정 어머니의 자녀양육경험 들여다보기)

  • Oh, Ok Sun ;Kim, Sung Bong
    • Korean Journal of Culture and Social Issue
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    • v.18 no.2
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    • pp.235-260
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    • 2012
  • This study was aimed at looking into and understanding child-rearing experience of mothers from multicultural families based on the grounded theory, one of the qualitative research methods. For this, twelve mothers from multicultural families were selected and data were collected through in-depth interviews with them and then analyzed through the open coding, axial coding and selective coding. The analysis suggested that main phenomena mothers from multicultural families experienced are the conflict of child-rearing and educational crisis, and the confused identity of parenting. These main phenomena had much to do with contextual factors such as economic hardship, lower level of the Korean language, cultural differences, prejudices and ignorance. The severeness of conflict and crisis of child-rearing and the intensity of identity confusion for parenting depended on arbitral conditions such as family bonds, positive expectation for the future of their children, and the help of supportive systems. Mothers were dealing with difficulties of child-rearing through action and interaction of resignation and denial, introspection and the intention to overcome difficulties, and the capacity building. As a result, mothers from multicultural families acknowledged that there is a limit to their position and roles they can play and tried to change in order to resolve problems related to their children, positioning themselves for more active lives in Korean society. Through discussion based on the findings of the study, this study can help better understand child-rearing experience of mothers from multicultural families and suggest several directions for future researches on multicultural families.

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An Exploratory Study on Work Conflict Experience (직장 내 갈등경험의 과정에 대한 탐색적 연구)

  • Dawon Rhee;Sunhee Lee;Min Han
    • Korean Journal of Culture and Social Issue
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    • v.20 no.3
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    • pp.205-233
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    • 2014
  • This study aims to identify work conflicts in Korean socio-cultural context by applying grounded theory. Survey has been conducted through in-depth interviews with 11 different employees from various occupational categories. Data collected from the survey were then analyzed based on the grounded theory of Strauss and Corbin (1998), thus resulted in a paradigm model consisting of 31 categories, 63 subcategories, and 100 concepts by open coding. Axial coding was then conducted and the results were as follows. The causal condition was the 'character of an opponent'. Contextual conditions which affect the causal condition were 'situational characteristics', 'character of an opponent', 'character of oneself', and their 'mutuality'. 'Negative feeling' was the central phenomena of work conflict and action/interaction strategies were verified to be 'avoidance', 'expression', 'effort toward solving problems' and 'increasing conflict'. Intervening conditions were 'interrelation', 'intervention', and 'group/task characteristics'. The consequences were organized as 'conflict continuance', 'personnel change' and 'positive effect'. Through selective coding, 'managing with the conflict' was derived as core-category and three different types of management were classified. Ultimately, this study shows how employees work in Korea experience the work conflicts and what kinds of socio-cultural factors have influence on the work conflicts, which can supplement previous inadequate empirical research. Also, this study can provide implications and suggestions as a fundamental integrated model for the future empirical research on work conflicts.

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Study on the Occurrence of Tunnel Damage when a Large-scale Fault Zone Exists at the Top and Bottom of a Tunnel (대규모 단층대가 터널 상하부에 존재하는 조건에서 터널 변상 사례 연구)

  • Jeongyong Lee;Seungho Lee;Nagyoung Kim
    • Journal of the Korean GEO-environmental Society
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    • v.24 no.12
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    • pp.53-60
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    • 2023
  • Recently, along with the improvement of high-speed rail and road design speed, the proportion of tunnel construction work is increasing proportionally. In particular, the construction of long tunnels is rapidly increasing due to the mountainous terrain of our country. In this way, due to the trend of tunnels becoming longer, it is difficult to design and construct tunnels by avoiding fault zones. In the case of tunnel construction in mountainous areas, ground investigation is often difficult even during design due to the topographical conditions, making precise ground investigation difficult, and as a result, the upper part of the tunnel is damaged during tunnel construction. When fault zones, which are vulnerable to weathering, exist, the stability of the tunnel during excavation is directly affected by the fault zone distribution, strength characteristics, and groundwater distribution range. In particular, when a fault zone is distributed in the upper part of a tunnel, damage such as tunnel collapse and excessive displacement may occur, and in order to prevent this in advance, countermeasures must be established through analysis of similar cases. Therefore, in this study, when a large-scale fault zone exists in the upper part of a tunnel, the relationship and characteristics of damage to the tunnel structure were analyzed.

Neural Network-Based Prediction of Dynamic Properties (인공신경망을 활용한 동적 물성치 산정 연구)

  • Min, Dae-Hong;Kim, YoungSeok;Kim, Sewon;Choi, Hyun-Jun;Yoon, Hyung-Koo
    • Journal of the Korean Geotechnical Society
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    • v.39 no.12
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    • pp.37-46
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    • 2023
  • Dynamic soil properties are essential factors for predicting the detailed behavior of the ground. However, there are limitations to gathering soil samples and performing additional experiments. In this study, we used an artificial neural network (ANN) to predict dynamic soil properties based on static soil properties. The selected static soil properties were soil cohesion, internal friction angle, porosity, specific gravity, and uniaxial compressive strength, whereas the compressional and shear wave velocities were determined for the dynamic soil properties. The Levenberg-Marquardt and Bayesian regularization methods were used to enhance the reliability of the ANN results, and the reliability associated with each optimization method was compared. The accuracy of the ANN model was represented by the coefficient of determination, which was greater than 0.9 in the training and testing phases, indicating that the proposed ANN model exhibits high reliability. Further, the reliability of the output values was verified with new input data, and the results showed high accuracy.

An Experimental Study on NOx Emissions with Hydrogen and Natural gas Co-firing for EV burner of GT24 (GT24 가스터빈용 EV 버너의 수소혼소에 따른 질소산화물 배출 특성에 대한 실험적 연구)

  • Jeongjae Hwang;Won June Lee;Kyungwook Min;Do Won Kang;Han Seo Kim;Min Kuk Kim
    • Journal of the Korean Institute of Gas
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    • v.27 no.4
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    • pp.85-91
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    • 2023
  • In this study, an experimental study was conducted on the flame behavior, combustion dynamics, and NOx emission characteristics for hydrogen co-firing with the EV burner which is the first stage combustor of GT24. It was confirmed that as the hydrogen co-firing rate increases, the NOx emission increases. This change was elucidate to be the result of a combination of changes in penetration depth due to changes in fuel density, reduction in fuel mixing due to changes in flame position due to increased flame propagation speed, and oscillation of fuel mixedness due to combustion instability. Through pressurization tests in the range of 1.3 to 3.1 bar, NOx emission characteristics under high-pressure operating conditions were predicted, and based on this, the hydrogen co-firing limits of the EV burner was evaluated.

The Impact of Childhood Abuse Experience on Adults' Disconnection/Rejection Schemas: A Comparison of Moderating Effects of Inhibition and Reinterpretation (아동기 학대 경험이 성인의 단절/거절도식에 미치는 영향 :억제와 재해석의 조절효과 비교)

  • HANNAH PARK
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.3
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    • pp.165-172
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    • 2024
  • This study illuminates the relationship between childhood abuse experiences and early maladaptive schemas, and compares the moderating effects of expressive suppression and cognitive reappraisal within this relationship. Conducting a self-report survey among 220 graduate students in Daejeon and Chungcheong regions, data from 210 participants were analyzed. The results notably revealed that the interaction effect of suppression, but not cognitive reappraisal, significantly moderates the relationship between childhood abuse experiences and disconnection/rejection schemas. Specifically, high levels of expressive suppression were associated with a decrease in the negative impact of childhood abuse on disconnection/rejection schemas, whereas low levels of suppression increased this negative impact. This suggests that for individuals with long-standing early maladaptive schemas, which have solidified over time akin to personality traits, cognitive reappraisal strategies may be less effective in inducing change. Conversely, expressive suppression strategies may more effectively reduce the intensity of disconnection/rejection schemas, among other early maladaptive schemas. These findings provide important implications for understanding the long-term effects of childhood abuse and developing intervention strategies to mitigate its resultant maladaptive schemas. Based on the outcomes of this study, suggestions for future research are discussed, along with the potential applicability and limitations of suppression and reappraisal strategies in psychological interventions.

Limitations in Using JCR Impact Factor Rankings for LIS Journals (JCR의 영향력지수 순위를 활용한 문헌정보학 분야 학술지 평가의 한계)

  • Eun-Ja Shin
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.35 no.3
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    • pp.57-76
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    • 2024
  • JCR's categorization significantly impacts the evaluation of research achievements in the field, particularly in information science and library science (IS & LS). Publishing in prestigious IS & LS journals often leads to lower evaluations due to their lower impact factor rankings. In contrast, publishing in higher-ranked Management Information Systems (MIS) journals classified under the IS & LS category is evaluated more favorably. Accordingly, this study analyzed the intersection of Library and Information Science (LIS) and MIS through an analysis of journal authors. This analysis was based on previous research that identified detailed subject areas of academic journals categorized under the IS & LS category in the JCR. As a result of the analysis, the intersection between the subfields of LIS and MIS was not substantial, and the strength of the connection was weak. Additionally, approximately 55% of universities in Seoul with LIS departments use JCR's journal rankings by subject category to assess research achievements. The findings suggest that JCR's subject category classification may negatively influence researchers' evaluations and potentially distort the academic publishing landscape. In the future, the issues with research achievement evaluation standards will need to be supplemented and improved. The results of this study are expected to serve as valuable fundamental data for policy improvement.