• Title/Summary/Keyword: stress state

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The character of teachers'and liberal teacher education (교사의 인성과 교양적 교사교육)

  • chung, Yun-Kyoung
    • (The)Korea Educational Review
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    • v.23 no.4
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    • pp.53-77
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    • 2017
  • This paper suggests that the meaning and the direction of character education should be understood and approached from a point of view which human formation is regarded as the essence of education. The best way of approach to the character education with this point of view could start from the teachers' character, because teachers are key actors for character formation of students. This study therefore places strong emphasis on the importance of teachers' character and suggesting liberal education, as a key solution, its aim is raising and developing the whole human being. The purpose of this study is to explore the possibility of liberal teacher education. With this purpose of study, the author argues the moral dimension of teaching and the importance of the teachers' role as a character builder in ch.II. In ch.III, the present state of teachers' character education is examined and is argued the necessity of liberal perspective for teacher education to stress the character formation of teachers. The liberal teacher education means that the teacher education is integrated into the quality of liberal education which emphasizes the whole human formation, transformation of personality and critical reflection for human formation. The ch. IV contains exploration of the possibility of liberal teacher education by discussing the compatibility between liberal education and vocational education. Furthermore, it covers how teacher education can reflect the quality of liberal education on the aim of teaching, contents and methods of teacher education concretely.

Martin Buber's Religious Socialism and Education (부버의 종교적 사회주의와 교육)

  • Kwak, Taejin;Kang, Sun-Bo
    • (The)Korea Educational Review
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    • v.22 no.3
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    • pp.169-192
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    • 2016
  • The purpose of this study is to investigate the relations between religious socialism and education of Martin Buber(1878~1965), a theistic existentialist. Buber suggested religious socialism as an alternative to modern capitalist society which has many problems. Buber's religious socialism is based on the communitarianism of Hasidism. Buber considered 'true' socialism must be based on decentralized associations, not based on centralized state apparatuses. For establishing this kind of socialism, human will and mind are the most important. Thus, education takes a very important role in the process of social transformation. According to Buber, education and pedagogy should contribute to overcoming modern society's problems by pursuing the construction of community(true socialist society). For Buber, education for individuals' character and education for building community are not separated but combined. That is, although education takes a main role in the social transformation, it should not be considered just as an instrument for the social transformation. This is the main distinction between Buber's thought and other key socialists' thoughts on social transformation and education, because many of socialists who stress the role of education in the process of social transformation, tend to regard education as an instrument for the social transformation. According to Buber, education can contribute to social transformation without being an instrument for the social transformation. These ideas of Buber on religious socialism and education have important implications for educators and educationalists who hope education contributes to solving problems of modern society.

Structural Behavior of Reinforced Concrete Members Subjected to Axial and Blast Loads Using Nonlinear Dynamic Analysis (비선형 동적해석을 이용한 축하중과 폭발하중을 동시에 받는 철근콘크리트 부재의 구조 거동 분석)

  • Lee, Seung-Hoon;Kim, Han-Soo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.35 no.3
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    • pp.141-148
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    • 2022
  • In this study, the structural behavior of reinforced concrete members under simultaneous axial and blast loads was analyzed. Nonlinear dynamic analysis verification was performed using the experimental data of panels under fundamental blast load as well as those of reinforced concrete columns subjected to axial and blast loads. Because Autodyn is a program designed only for dynamic analysis, an analysis process is devised to simulate the initial stress state of members under static loads, such as axial loads. A total of 80 nonlinear dynamic finite element analysis procedures were conducted by selecting parameters corresponding to axial load ratios and scaled distances ranging 0%~70% and 1.1~2.0 (depending on the equivalent of TNT), respectively. The structural behavior was compared and analyzed with the corresponding degree of damage and maximum lateral displacement through the changes in axial load ratio and scaled distance. The results show that the maximum lateral displacement decreases due to the increase in column stiffness under axial loads. In view of the foregoing, the formulated analysis process is anticipated to be used in developing blast-resistant design models where structural behavior can be classified into three areas considering axial load ratios of 10%~30%, 30%~50%, and more than 50%.

Folding Analysis of Paper Structure and Estimation of Optimal Collision Conditions for Reversal (종이구조물의 접기해석과 반전을 위한 최적충돌조건의 산정)

  • Gye-Hee Lee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.36 no.4
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    • pp.213-220
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    • 2023
  • This paper presents a model simulating the folding process and collision dynamics of "ddakji", a traditional Korean game played using paper tiles (which are also referred to as ddakji). The model uses two A4 sheets as the base materials for ddakji. The folding process involves a series of boundary conditions that transform the wing part of the paper structure into a twisted configuration. A rigid plate boundary condition is also adopted for squeezing, establishing the shape and stress state of the game-ready ddakji through dynamic relaxation analysis. The gaming process analysis involves a forced displacement of the striking ddakji to a predetermined collision position. Collision analysis then follows at a given speed, with the objective of overturning the struck ddakji--a winning condition. A genetic algorithm-based optimization analysis identifies the optimal collision conditions that result in the overturning of the struck ddakji. For efficiency, the collision analysis is divided into two stages, with the second stage carried out only if the first stage predicts a possible overturn. The fitness function for the genetic algorithm during the first stage is the direction cosine of the struck ddakji, whereas in the second stage, it is the inverse of the speed, thus targeting the lowest overall collision speed. Consequently, this analysis provides optimal collision conditions for various compression thicknesses.

Analysis on the Rigid Connections of the Drilled Shaft with the Cap for Multiple Pile Foundations (현장타설말뚝을 적용한 다주식 기초에서 말뚝과 캡의 강결합에 대한 분석)

  • Cho, Sung-Min
    • Journal of the Korean Geotechnical Society
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    • v.24 no.7
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    • pp.61-73
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    • 2008
  • Piles of a bridge pier are connected with the column through the pile cap (footing). Behavior of the pile foundation can be different according to the connection method between piles and the pile cap. Connection methods between pile heads and the pile cap are divided into two groups : rigid connections and hinge connections. Domestic design code has been specified to use rigid connection method for the highway bridge. In the rigid connection method, maximum bending moment of a pile occurs at the pile head and this helps the pile to prevent the excessive displacement. Rigid methods are also good to improve the seismic performance. However, some specifications prescribe that conservative results through investigations of both the fixed-head condition and the free-head condition should be reflected in the design. This statement may induce an over-estimated design for the bridge which has high-quality structures with casing covered drilled shafts and the PC-house contained pile cap. Because the assumption of free-head conditions (hinge connections) is unreal for the elevated pile cap system with multiple piles of the long span sea-crossing bridges. On the other hand, elastic displacement method to evaluate the pile reactions under the pile cap is not suitable for this type of bridges due to impractical assumptions. So, full modeling techniques which analyze the superstructure and the substructure simultaneously should be performed. Loads and stress state of the large diameter drilled shaft and the pile cap for Incheon Bridge which will be the longest bridge of Korea were investigated through the full modeling for rigid connection conditions.

Cannabidiol Inhibits Lipogenesis by Regulating Akt/AMPK-SREBP-1 Pathway in Sebocytes (피지세포에서 Akt/AMPK-SREBP-1 경로를 통한 CBD의 피지 합성 억제 효능)

  • Yoon Gyung Kwon;Ji Young Yoon;Hanon Lee;Dong Hyo Kim;Jun Hyo Lee;Diane M Thiboutot;Dae Hun Suh;Byoung Jun Park
    • Journal of Life Science
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    • v.33 no.4
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    • pp.343-348
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    • 2023
  • Acne is one of the most common skin diseases, mainly occurring in adolescence. The pathophysiology of acne involves not only hormonal, genetic and environmental factors, but also other factors including hyperseborrhea, inflammation, over-keratinization of follicular keratinocytes and overgrowth of Cutibacterium acnes (C. acnes). Cannabidiol (CBD) is known to relieve pain, stress and inflammation. Moreover, cannabis extracts containing CBD have been reported to be effective in treating acne. However, the therapeutic effect of CBD on acne remains unclear. Therefore, this study aimed to investigate the effect and mechanism of CBD on lipogenesis in SEB-1 sebocytes. We treated sebocytes with CBD and found that it not only inhibited lipid synthesis, but also inhibited cell proliferation by inducing apoptosis. We then demonstrated that sterol response element-binding protein-1 (SREBP-1) mediates the inhibitory effect of CBD on lipogenesis. Furthermore, Akt and adenosine monophosphate-activated protein kinase (AMPK), upstream regulators of SREBP-1, were regulated by CBD treatment. Taken together, our studies demonstrate that CBD inhibits adipogenesis by regulating the Akt/AMPK-SREBP-1 signaling pathway, providing potential for use as a therapeutic agent for acne. Further research is needed to confirm the effect of CBD on inflammation caused by hyperkeratosis, which will increase the possibility of using CBD for acne treatment.

The Prediction Method of the Small Strain Shear Modulus for Busan Clay Using CPT and DMT (CPT와 DMT를 이용한 부산점토의 최대전단탄성계수 추정방법에 관한 연구)

  • Hong, Sung-Jin;Yoon, Hyung-Ko;Lee, Jong-Sub;Lee, Woo-Jin
    • Journal of the Korean Geotechnical Society
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    • v.25 no.6
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    • pp.5-16
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    • 2009
  • The is study is to evaluate the small strain shear modulus ($G_{max}$) of Busan clay using in-situ penetration tests. A series of dilatometer tests (DMT) and piezocone penetration tests (CPTu) are performed at Busan newport and Noksan sites, and hybrid oedometer tests are also carried out on the specimens obtained from both sites. The $G_{max}$ is evaluated from the shear wave velocity ($V_s$) measured by the bender elements installed at the boundary of oedometer cell. By analyzing these data, the relationship of $G_{max}$ and state variables, such as confined stress and void ratio, is developed. The analysis of lab and in-situ test results reveals that the ratio of $G_{max}$ to $q_t$ is inversely proportional to the plasticity index while the ratio of $G_{max}$ to $E_D$ has a linear relationship with ($I/I_D$)$(p_a/{\sigma}'_v)^{0.5}$. Two correlations suggested in this study, based on CPT and DMT results, appear to provide reasonable predictions of the small strain shear modulus.

Behavior of Asphalt Pavement Subjected to a Moving Vehicle I: The Effect of Vehicle Speed, Axle-weight, and Tire Inflation Pressure (이동하중에 의한 시험도로 아스팔트 포장의 거동 분석)

  • Seo, Young Gook;Lee, Kwang-Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.5D
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    • pp.831-838
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    • 2006
  • An experimental/analytic study has been conducted to understand the adverse effects of low vehicle speed, high axle load and high tire pressure on the performance of asphalt pavements. Of 33 asphalt sections at KHC test road, two sections having different base layer thickness (180 mm versus 280 mm) are adopted for rollover tests. During the test, a standard three-axle dump truck maintains a steady state condition as moving along the wheel path of a passing lane, and lateral offsets and real travel speed are measured with a laser-based wandering system. Test results suggest that vehicle speed affects both longitudinal and transverse strains at the bottom of asphalt layer (290 mm and 390 mm below the surface), and even slightly influences the measured vertical stresses at the top of subbase and subgrade due to the dynamic effect of rolling vehicle. Since the anisotropic nature of asphalt-aggregate mixtures, the difference between longitudinal and transverse strains appears prominent throughout the measurements. As the thickness of asphalt pavement increases, the measured lateral strains become larger than its corresponding longitudinal strains. Over the limited testing conditions, it is concluded that higher axle weight and higher tire pressures induce more strains and vertical stresses, leading to a premature deterioration of pavements. Finally, a layered elastic analysis overestimates the maximum strains measured under the 1st axle load, while underestimating the maximum vertical stress in both pavement sections.

Probabilistic Risk Assessment of a Cable-Stayed Bridge Based on the Prediction Method for the Combination of Failure Modes (붕괴모드 조합 예측법에 의한 PSC사장교의 위험도평가)

  • Park, Mi-Yun;Cho, Hyo-Nam;Cho, Taejun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.4A
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    • pp.647-657
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    • 2006
  • Probabilistic Risk Assessment considering statistically random variables is performed for the preliminary design of a Cable Stayed Bridge, which is Prestressed Concrete Bridge consisted of cable and plate girders, based on the method of Working Stress Design and Strength Design. Component reliabilities of cables and girders have been evaluated using the response surface of the design variables at the selected critical sections based on the maximum shear, positive and negative moment locations. Response Surface Method (RSM) is successfully applied for reliability analyses for this relatively small probability of failure of the complex structure, which is hard to obtain through Monte-Carlo Simulations. or through First Order Second Moment Method that can not easily calculate the derivative terms of implicit limit state functions. For the analysis of system reliability, parallel resistance system consisting of cables and plate girder is changed into series connection system and the result of system reliability of total structure is presented. As a system reliability, the upper and lower probabilities of failure for the structural system have been evaluated and compared with the suggested prediction method for the combination of failure modes. The suggested prediction method for the combination of failure modes reveals the unexpected combinations of element failures in significantly reduced time and efforts compared with the previous permutation method or system reliability analysis method, which calculates upper and lower bound failure probabilities.

Response Analysis of Nearby Structures with the Consideration of Tunnel Construction and Ground Conditions (터널시공 및 지반조건을 반영한 인접구조물의 거동분석)

  • Son, Moorak;Yun, Jongcheol
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.6C
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    • pp.255-263
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    • 2010
  • This paper investigates the effects of tunnelling-induced ground movements on nearby structures, considering soil-structure interactions of different construction (ground loss) and soil characteristics. The response of four-story block structures, which are subjected to tunnelling-induced ground movements, has been investigated in different construction (ground loss) and soil conditions using numerical analysis. The structures for numerical analysis has been modelled using Discrete Element Method (DEM) to have real cracks when the shear and tensile stress exceed the maximum shear and tensile strength. The response of four-story block structures has been investigated with a ground movement magnitude and compared in terms of construction (ground loss) and soil conditions considering the magnitude of deformations and cracks in structures. In addition, the damage levels, which are possibly induced in structures, has been provided in terms of construction (ground loss) and soil conditions using the state of strain damage estimation criterion (Son and Cording, 2005). The results of this study will provide a background for better understandings for controlling and minimizing building damage on nearby structures due to tunnelling-induced ground movements.