• 제목/요약/키워드: Critical Analysis

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원통드로잉 성형에 있어서 Puckering 억제조건과 FEM-Simulation 해석 (On the Critical Tension Force and Analysis by the FEM for Puckering in the Cylindrical Cup-Drawing)

  • 후등학;임철록;정태훈
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1994년도 추계학술대회 논문집
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    • pp.80-94
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    • 1994
  • As for axisymmetirc sheet metal forming, a kind of pick-up apparatus for body-wrinkling is deviced. Experiments with both hemispherical and flat headed punches, with various clearances between punch and die, with respect to three kinds of materials each of which has two thicknesses, are performed. Firstly the process of evolution of body-wrinkling is observed. Then the critical blank-holding force (or meridional tensile force) for suppression of body-wrinkling at a specified punch-stroke is measured for all cases mentioned above. An empirical formula for it is proposed. Deformation patterns and stress distributions are analysed by the use of FEM. A simplified critical condition for body-wrinkling is formulated and introduced into the FEM program. And its effectiveness is checked by comparison with the experimental results. Using this FEM system, the governing factors of body-wrinkling are cleared up.

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현대 패션의 DE&I에 대한 비판적 담론분석 -뉴욕타임즈의 인종 기사를 중심으로- (Critical Discourse Analysis of Diversity, Equity, and Inclusion in Contemporary Fashion -Analyzing Articles on Race in The New York Times-)

  • 이명선;임은혁
    • 한국의류학회지
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    • 제47권3호
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    • pp.544-559
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    • 2023
  • Social discourses surrounding diversity, equity, and inclusion (DE&I) in the fashion industry are vital as they extend beyond language and encompass social practices. This study aimed to understand how discourses on DE&I with in the fashion industry are reconstructed and practiced in society. Therefore, this paper analyzed DE&I in the fashion industry, by focusing on the New York Times articles, employing a quantitative research model based on corpus analysis and a qualitative approach through critical discourse analysis. Results of the analysis of textual practice, showed that the New York Times emphasized black individuals as the central discourse and created a critical racial narrative regarding DE&I in the fashion industry characterized by a dichotomy of black vs. white confrontation. Furthermore, results of the discourse practice analysis revealed that the dichotomy of racial confrontation in the New York Times article tended to select the subject of discourse related to racial DE&I in the fashion industry according based on social and historical context. Thirdly, the analytical results of sociocultural practices indicated that the dichotomous racial discourse between black and white, propagated by the New York Times, spread across social media, transforming fashion from an industry to a domain where black individuals struggle for human rights.

Optimum location for the belt truss system for minimum roof displacement of steel buildings subjected to critical excitation

  • Kamgar, Reza;Rahgozar, Peyman
    • Steel and Composite Structures
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    • 제37권4호
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    • pp.463-479
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    • 2020
  • Currently, there are many lateral resisting systems utilized in resisting lateral loads being produced in an earthquake. Such systems can significantly reduce the roof's displacement when placed at an optimum location. Since in the design of tall buildings, the minimum distance between adjacent buildings is important. In this paper, the critical excitation method is used to determine the best location of the belt truss system while calculating the minimum required distance between two adjacent buildings. For this purpose, the belt truss system is placed at a specific story. Then the critical earthquakes are computed so that the considered constraints are satisfied, and the value of roof displacement is maximized. This procedure is repeated for all stories; i.e., for each, a critical acceleration is computed. From this set of computed roof displacement values, the story with the least displacement is selected as the best location for the belt truss system. Numerical studies demonstrate that absolute roof displacements induced through critical accelerations range between 5.36 to 1.95 times of the San Fernando earthquake for the first example and 7.67 to 1.22 times of the San Fernando earthquake for the second example. This method can also be used to determine the minimum required distance between two adjacent buildings to eliminate the pounding effects. For this purpose, this value is computed based on different standard codes and compared with the results of the critical excitation method to show the ability of the proposed method.

비판적 사고성향과 문제해결과정이 간호업무수행에 미치는 영향 (Influence of Nurses' Performance with Critical Thinking and Problem Solving Process)

  • 최혜란;조동숙
    • 여성건강간호학회지
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    • 제17권3호
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    • pp.265-274
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    • 2011
  • Purpose: This study determined the correlation between nurses' critical thinking disposition; problem solving process; and nursing performance. It also examined the impact of critical thinking disposition and problem solving process on nursing performance. Methods: The data was collected from 419 nurses. Descriptive statistics, t-test, ANOVA, scheffe test, pearson correlation analysis and multiple regression analysis were performed. Results: Nursing performance showed that there were differences according to age, marital status, educational level, total number of years in the career and the length of employment in the present department. The problem solving process showed differences in the educational level. Critical thinking disposition showed differences according to age, educational level and total number of years in the career. Problem solving process and nursing performance showed a positive relationship whereas critical thinking disposition and nurses' performance showed a positive relationship. Factors affecting nursing performance, were nurses' age, duration of employment in the present department, problem solving process and critical thinking disposition. This model was statistically significant and showed 22.1% of the total variance. Conclusion: The attention of nursing administrators should be drawn to the consideration that a certain amount of experience in the current department is positively related to nursing performance. Furthermore, in order to provide a improvement in professional nursing performance, educational programs towards nurses' critical thinking disposition and problem solving process should be provided.

Load-carrying capacities and failure modes of scaffold-shoring systems, Part II: An analytical model and its closed-form solution

  • Huang, Y.L.;Kao, Y.G.;Rosowsky, D.V.
    • Structural Engineering and Mechanics
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    • 제10권1호
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    • pp.67-79
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    • 2000
  • Critical loads and load-carrying capacities for steel scaffolds used as shoring systems were compared using computational and experimental methods in Part I of this paper. In that paper, a simple 2-D model was established for use in evaluating the structural behavior of scaffold-shoring systems. This 2-D model was derived using an incremental finite element analysis (FEA) of a typical complete scaffold-shoring system. Although the simplified model is only two-dimensional, it predicts the critical loads and failure modes of the complete system. The objective of this paper is to present a closed-form solution to the 2-D model. To simplify the analysis, a simpler model was first established to replace the 2-D model. Then, a closed-form solution for the critical loads and failure modes based on this simplified model were derived using a bifurcation (eigenvalue) approach to the elastic-buckling problem. In this closed-form equation, the critical loads are shown to be function of the number of stories, material properties, and section properties of the scaffolds. The critical loads and failure modes obtained from the analytical (closed-form) solution were compared with the results from the 2-D model. The comparisons show that the critical loads from the analytical solution (simplified model) closely match the results from the more complex model, and that the predicted failure modes are nearly identical.

Self Field Effect Analysis of Bi-2223 Tape-Stacked-Cable With Constant Current Density Assumption

  • Nah, Wansoo;Joo, Jinnho
    • Transactions on Electrical and Electronic Materials
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    • 제1권1호
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    • pp.12-16
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    • 2000
  • In this paper, we analyze self field effects of Bi-2223 tape-stacked cable assuming constant current density in the cross section of stacked cable. Generally, the critical current of Bi-2223 tape-stacked-cable in much less than the total summation of critical currents of each tape, which is mainly due to the self magnetic fields of the cable itself. Therefore, to predict the critical current of Bi-2223 tape-stacked-cable, we needs to analyze the self filed effects on the stacked cable as well as critical current density data(J$\_$C/) of one tape. To make it more complex, the critical current degradation of Bi-2223 tape is an-isotropic; the critical current is lower in the normal magnetic field(to the tape surface) than in the parallel field. In the paper, a novel approach to predict the critical current of a Bi-2223 tape-stacked-cable from a J$\_$C/-B curve of one tape is presented with the assumption of constant current density across the stacked cable, The approach basically includes the load analysis of the stacked tapes, and its usefulness is confirmed by the experimental data.

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비틀림 비선형성을 갖는 2차원 익형의 Critical Slowing Down 을 이용한 Limit Cycle Flutter 예측 인자 (Warning Signal for Limit Cycle Flutter of 2D Airfoil with Pitch Nonlinearity by Critical Slowing Down)

  • 임주섭;이상욱;김태욱
    • 한국항공운항학회지
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    • 제21권4호
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    • pp.47-52
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    • 2013
  • In this paper, limit cycle flutter induced by Hopf bifurcation is studied with nonlinear system analysis approach and observed for the critical slowing down phenomenon. Considering an attractor of the dynamics of a system, when a small perturbation is applied to the system, the dynamics converge toward the attractor at some rate. The critical slowing down means that this recovery rate approaches zero as a parameter of the system varies and the size of the basin of attraction shrinks to nil. Consequently, in the pre-bifurcation regime, the recovery rates decrease as the system approaches the bifurcation. This phenomenon is one of the features used to forecast bifurcation before they actually occur. Therefore, studying the critical slowing down for limit cycle flutter behavior would have potential applicability for forecasting those types of flutter. Herein, modeling and nonlinear system analysis of the 2D airfoil with torsional nonlinearity have been discussed, followed by observation of the critical slowing down phenomenon.

Raising Critical Awareness of Watching American TV Cartoons in an ESL Context

  • Suh, Young-Mee;Jung, Yoosun
    • 영어어문교육
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    • 제18권3호
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    • pp.223-242
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    • 2012
  • The study focused on exploring the ways that young ESL learners can cultivate media literacy by asking critical questions about the messages embedded in popular American TV cartoons. The participants in the study were five Korean children who came from three different families that had been living in a Midwestern college-town in the U. S. for less than two years. Research methods include analysis of interviews, video-taped sessions and photos of children's drawings. The children were asked about their American cartoon viewing habits as well as critical questions after watching two episodes of their favorite cartoons-Pok$\acute{e}$mon and SpongeBob. The analysis revealed that on one hand popular culture played an important role in helping children to adjust to a new culture and in motivating them to learn English. Further, the children believed that watching American cartoons was helping them improve their English skills. On the other hand, it appeared that they were not accustomed to being asked critical questions and thinking critically while watching American cartoons. Participation in the study increased the children's familiarity with critical questions and critical thinking to varying degrees. Pedagogical implications and suggestions for teachers are discussed.

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중환자실 간호사의 인간중심 간호 측정도구 개발 (Development and Validation of a Measurement to Assess Person-centered Critical Care Nursing)

  • 강지연;조영신;정연진;김수경;윤선영;심미영
    • 대한간호학회지
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    • 제48권3호
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    • pp.323-334
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    • 2018
  • Purpose: The purpose of this study was to develop a scale to measure person-centered critical care nursing and verify its reliability and validity. Methods: A total of 38 preliminary items on person-centered critical care nursing were selected using content validity analysis of and expert opinion on 72 candidate items derived through literature review and qualitative interviews. We conducted a questionnaire survey with 477 nurses who worked in intensive care units. The collected data were analyzed using exploratory factor analysis (EFA) and confirmative factor analysis (CFA) with SPSS and AMOS 24.0 program. Results: EFA was performed with principal axis factor analysis and Varimax rotation. The 15 items in 4 factors that accounted for 50.8% of the total variance were identified by deleting the items that were not meet the condition that the commonality should be .30 or more and the factor loading over .40. We named the factors as compassion, individuality, respect, and comfort, respectively. The correlation coefficient between this scale and the Caring Perception Scale was r=.57 (p<.001), which determined concurrent validity. The item-total correlation values ranged from .39 to .63, and the internal consistency for the scale was Cronbach's ${\alpha}=.84$. Conclusion: The reliability and validity of the 15 item person-centered critical care nursing scale were verified. It is expected that the use of this scale would expand person-centered care in critical care nursing.

임계전류, 임계온도 및 회복시간을 고려한 초전도 전력케이블의 EMTDC 모델 컴포넌트 개발 (Development of EMTDC model component for HTS power cable considering critical current, critical temperature and recovery time)

  • 방종현;김재호;심기덕;조전욱;윤재영;박민원;유인근
    • 한국초전도ㆍ저온공학회논문지
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    • 제8권1호
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    • pp.39-44
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    • 2006
  • Before applying HTS power cable to the real utility. system analysis should be carried out by some simulation tools . Hereby the electrical power system analysis is very important for practical use of HTS devices. Nowadays PSCAD/EMTDC simulation tool is one of the most popular and useful analysis tool for the electrical power system analysis. Unfortunately the model component for HTS power cable is not provided in the PSCAD/EMTDC simulation tool In this paper. the EMTDC model component for HTS power cable has been developed considering critical current, critical temperature and recovery time constant that depend on the sorts of HTS wire. The numerical model of HTS Power cable in PSCAD/EMTDC was designed by using the real experimented data obtained from the real HTS 1G wire test. The utility application analysis of HTS power cable was also performed using the developed model component and the parameters of the real utility network in this study. The author's got good results. The developed model component for HTS power cable could be variously used when the power system includes HTS power cable, especially it will be readily analyzed by PSCAD/EMTDC in order to obtain the data for the level of fault current power flow, and power losses, and so on.