• Title/Summary/Keyword: continuum

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A Numerical Study on Safety According to the Excavation Step for Large Cross Section Tunnel (대단면 터널굴착에 있어서 굴착순서에 따른 수치해석적 안정성 검토)

  • Jung, Hee-sun;Yoon, Ji-sun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.7 no.4
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    • pp.335-341
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    • 2005
  • In construction of a large cross section NATM tunnel, to keep the tunnel face stability by the ground itself bench cut method is commonly used. In order to necessity of partial face excavation method, we have to look for more enhanced method that can maintain better stress intensity. This paper presents a stress distribution of the Center Diaphragm Method from the partial face excavation methods, with the numerical analysis, and induced the optimal face distance, which is minimizing stress concentration and the optimal excavation step. Commerical 3 dimensional continuum analyzing FLAC-3D Ver. 2.1 program is used for the analysis. Analyses were performed to investigate ground behavior for tunnels with variable bench-length varying from 2m to 40m.

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Multiple Stakeholder Perspectives on Cancer Stigma in North India

  • Gupta, Adyya;Dhillon, Preet K;Govil, Jyotsna;Bumb, Dipika;Dey, Subhojit;Krishnan, Suneeta
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.14
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    • pp.6141-6147
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    • 2015
  • Background: Cancer is a leading cause of death worldwide. A large proportion of cancer deaths are preventable through early detection but there are a range of social, emotional, cultural and financial dimensions that hinder the effectiveness of cancer prevention and treatment efforts. Cancer stigma is one such barrier and is increasingly recognized as an important factor influencing health awareness and promotion, and hence, disease prevention and control. The impact and extent of stigma on the cancer early detection and care continuum is poorly understood in India. Objectives: To evaluate cancer awareness and stigma from multiple stakeholder perspectives in North India, including men and women from the general population, health care professionals and educators, and cancer survivors. Materials and Methods: A qualitative study was conducted with in-depth interviews (IDIs) and focus group discussions (FGDs) among 39 individuals over a period of 3 months in 2014. Three groups of participants were chosen purposively - 1) men and women who attended cancer screening camps held by the Indian Cancer Society, Delhi; 2) health care providers and 3) cancer survivors. Results: Most participants were unaware of what cancers are in general, their causes and ways of prevention. Attitudes of families towards cancer patients were observed to be positive and caring. Nevertheless, stigma and its impact emerged as a cross cutting theme across all groups. Cost of treatment, lack of awarenes and beliefs in alternate medicines were identified as some of the major barriers to seeking care. Conclusions: This study suggests a need for spreading awareness, knowledge about cancers and assessing associated impact among the people. Also Future research is recommended to help eradicate stigma from the society and reduce cancer-related stigma in the Indian context.

Development of Degenerated Beam Elements Using Higher-Order Displacement Profile (고차(高次) 변위(變位)를 고려(考慮)한 요소(要素)의 해석(解析))

  • Shin, Young Shik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.2 no.3
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    • pp.75-86
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    • 1982
  • The degeneration of two classes of thick beam elements has been conducted, one (DB6) based on the conventional Timoshenko beam assumptions whereas the other (DB7) based on the assumed cubic axial displacement profile. While an adjustable shear correction factor is required for the DB 6 element to compensate for the unrealistic distribution of shear strain across the thickness, the DB 7 element assumes the more realistic quadratic profile of shear strain at the outset. With the plane-stress continuum solution as reference, solutions obtained by these two element models are compared with the analytical Timoshenko solution, the analytical thin beam solution and several available solutions of other existing beam elements. The result indicates that the performance of the higher order beam element DB 7 is consistently superior to any others. This is true for the whole range of aspect ratios of beam, in both static and free vibration analyses.

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Numerical estimation for safety factors of tunnels considering the failure of supports (지보재 파괴를 고려한 터널 안전율의 수치해석적 산정 연구)

  • You, Kwang-Ho;Park, Yeon-Jun;Hong, Keun-Young;Lee, Hyun-Koo;Kim, Jea-Kwon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.7 no.1
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    • pp.37-49
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    • 2005
  • In a tunnel, failure of its supports can cause failure of the tunnel. Therefore it is important to estimate safety factor of the tunnel which the failure of its supports is taken into account. In previous studies, supports of tunnels were usually modelled as beam elements. The failure of the supports was decided by comparing the allowable stress and the calculated bending stresses inside the beam elements in estimating safety factor of the tunnel considering the failure of its supports. In this study, it is suggested how to model the supports properly. To this end, supports of a tunnel were modelled by both beam (elastic) elements and continuum (elasto-plastic) elements in two dimensional numerical analyses. Meanwhile, it was analyzed how rock mass class, coefficient of lateral pressure, shotcrete thickness, the existence of rock bolt, and excavation method had an effect on the safety factor of a tunnel.

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Embarrassment; a concept analysis (당혹감(embarrassment); 개념분석)

  • Cho, Eun-Jung;Chung, Bok-Yae
    • Korean Journal of Adult Nursing
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    • v.14 no.2
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    • pp.276-286
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    • 2002
  • Purpose: The concept of embarrassment as an unpleasant emotion is important in caring for those who are in the continuum of illness and health requiring body care and facing sexual problems. In spite of its nursing implication, embarrassment has not been focused in nursing research. Therefore, the purpose of this paper is to develope a conceptual analysis of embarrassment. This analysis would help to understand comprehensively an embarrassing situation in which an intimate relationship between nurse and patient regarding body care of the patient could develope. Futhermore, it would be a basis for developing strategies for prevention of embarrassment which could lead for both patient and nurse to emotionally vulnerable situation because of their failure of self-presentation (impression management). Method: The concept analysis model suggested by Walker and Avant (1988) is used to clarify what is meant by the term 'embarrassment'. Result: This analysis defines the attributes of embarrassment such as follows. First, embarrassment is often attributed to situational factors interrupting a smooth interaction such as intimacy, confusion, vulnerability, exposure of interaction and characteristics of audience. Second, embarrassment is closely related with cognitive factor such as fear of losing face resulted from a behaviour being out of line. Third, embarrassment is closely associated with dispositional factor such as embarrassability. Fourth, embarrassment is an unpleasant and unwanted emotion arising reactively after an interaction had occurred. Fifth, embarrassment encloses physical, physiological and behavioral aspects such as a variety of unique and easily noticeable reactions and a pattern of verbal and non-verbal behaviour for coping in an embarrassing situation. The antecedents were normally socialized adolescents with normal cognitive ability, concern of losing face, embarrassability, embarrassing events related with situational intimacy, confusion, vulnerability, exposure of interaction and characteristics of audience, physical, behavioral blunders resulting in a failure of impression management. The consequences were an emotional coping behaviour, audience's embarrassment responses, and verbal and non-verbal coping strategies of interactional participants. Conclusion: It is hoped that this analysis will stimulate further exploration of this concept and study for developing systematic assessment and nursing practice that diminishes embarrassment of interactional participants.

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Finite element analysis for 3-D self-contact problems of C.v.joint rubber boots (3차원 자체접촉을 위한 유한요소해석에 의한 등속조인트 고무부트의 변형해석)

  • Lee, H.W.;Kim, S.H.;Lee, C.H.;Huh, H.;Lee, J.H.;Oh, S.T.
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.12
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    • pp.2121-2133
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    • 1997
  • A finite element code is developed for 3-D self-contact problems, using continuum elements with a SRI(Selective Reduced Integration) scheme to prevent locking phenomenon by the incompressibility of rubber. Contact treatment is carried out in two ways : using the displacement constraints in case of rigid contact ; and imposing the same contact forces on two contact boundaries in case of self-contact. The finite element code developed is applied to the deformation analysis of C.V.joint boots which maintain lubrication conditions and protect the C.V.joint assembly from impact and dust. The boot accompanies large rotation depending on the rotation of the wheel axis and leading to the self-contact phenomena of the boot bellows. Since this contact phenomenon causes wear of the product and has great influence on the endurance life of the product, it is indispensable to carry out stress analysis of the rubber boots. In case of self-contact, various methods for determining contact forces have been suggested with an appropriate contact formulation. Especially, the types of penetration in self-contact are modularized to accelerate conputation with a contact algorithm.

Particle Charging and Collection in Two-Stage, Parallel-Plate Electrostatic Precipitators (2단 평행판 정전식 집진기에서의 입자하전 및 포집)

  • 오명도;유경훈;이준식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.2
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    • pp.432-445
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    • 1994
  • From a theoretical analysis point of view, the 2-stage precipitator is decomposed into two units: charging cell and collecting cell. Collection efficiency predictions of the two-stage parallel-plate electrostatic precipitator have been performed theoretically incorporating with the charging and the collecting cells. Particle trajectorise passing the charging cell have been modeled as a simple one. Particle charge distribution at the outlet of the charging cell is calculated through integration of the present unipolar combined charging rate along the entire particle trajectory, and average charge of particles at the outlet of the charging cell is obtained from the particle charge distribution. As for the collecting cell, the diminution of particle concentration along the longitudinal direction of the collecting cell is investigated considering the conventional Deutsch's theory and the laminar theory. One should note that the collection efficiency formula derived is based on monodisperse aerosols. It has been confirmed through the analysis that predictions of particle charge by applying White's unipolar diffusion charging theory overpredict actual cases in the continuum regime, while predictions by Fuch's unipolar diffusion charging theory indicate the reasonable result in the same regime. Theoretical predictions of collection efficiency are also compared with the available experimental results. Comparisons show that the experimental results are consistently located in the collection efficiency region bounded by the two limits, the Deutsch and the laminar collection efficiencies. Finally design parameters of the 2-stage electrostatic precipitator have been investigated systematically through the one-variable-at-a-time method in terms of collection efficiency. Applied voltages on the corona wire of the charging cell and the plate of the collecting cell, and the average air velocity have been selected as the design parameters.

Meaning Analysis (의미 분석)

  • 이건원
    • Proceedings of the Korean Society for Cognitive Science Conference
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    • 2000.06a
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    • pp.419-423
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    • 2000
  • 성공적인 의사소통의 경우에 성(性)이, 이(理)와 명(命)으로 나타난 것이 같다. 진리(aletheia)가, 언어(logos)와 운명(moira)으로 나타난 것들이 일치하는 것이 성공적인 언화행위가 된다. 측정대상(melos)과 본체(ousia)가 구분되는 것은 언어와 운명의 괴리가 있을 수 있기 때문이다. 체계적인 언어처리의 지식기반을 측정대상에 한정한다. (1) 철학의 시작은 더 옳은 언어표현의 정의(definition)로 이전의 잘못 사용된 언어처리를 대체시키는 것으로 소크라테스는 보았다. [R. Crossman] (2)잘못을 지적하는 등에(Tabanidae)의 역할과 옳은 지식의 상기를 돕는 산파법(maieutics)이 소크라테스의 의미분석의 방법이다. [R. Crossman] (3) 언어를 통하여 진리를 추구한다는 입장(via language)에서 한 언어표현이 그 진리의 운명으로 나타남과 어긋날 때, 운명을 택하는 것은 조화 보다 더 안정의 우위를 인정하는 논리적인 입장으로 합리성 보다 실용(pragma)의 우위를 인정하는 것이다. [W. Quine] (4) 공동체의 공통규범의 추구는 그 언어 속의 공통의 형식 또는 법칙의 추구에 기초하는 것이 자연스럽다. 여기에서 그 언어사용은 그 기저의 법칙(underlying rule)에 개입한다는 입장에 기초한다. [J. Searle] (5) 진리의 언어표현과 운명적인 사태들 사이의 괴리를 처리하기 위하여 체계적인 언어표현의 대상(The Young Tableaux)과 실제(The continuum)의 구분을 수용한다. [AMS(2000)]언어표현의 대상은 나타난 것(顯)이고 실제에는 나타나지 않은 것도 있다. [伊川, 明道] (6) 이 나타난 것과 나타나지 않은 것에 간격이 없다는 것(顯微無間)은 그 의사소통이 성공적인 것이라는 것을 말한다. 따라서 그 언어의 표현완전성(functional completeness)은 언화행위가 성공적이라는 것이다. [J. Searle] (7) 수로 쓰인 것(象數)과 시로 쓰인 것(義理)이 하나인 것은 그 나타난 것과 나타나지 않은 것들 사이에 어떠한 틈도 없음을 말한다. [成中英] (8) 공통의 규범의 공통성 속에 규범적인 측면이 벌써 있다. 공통성에서 개인적이 아닌 공적인 규범으로의 전이는 규범, 가치, 규칙, 과정, 제도로의 전이라고 본다. [C. Morrison] (9) 우리의 언어사용에 신비적인 요소를 부인할 수가 없다. 넓은 의미의 발화의미(utterance meaning) 속에 신비적인 요소나 애정표시도 수용된다. 의미분석은 지금 한글을 연구하고, 그 결과에 의존하여서 우리의 실제의 생활에 사용하는 $\boxDr$한국어사전$\boxUl$등을 만드는 과정에서, 어떤 의미에서 실험되었다고 말할 수가 있는 언어과학의 연구의 결과에 의존하여서 수행되는 철학적인 작업이다. 여기에서는 하나의 철학적인 연구의 시작으로 받아들여지는 이 의미분석의 문제를 반성하여 본다.

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Dynamic Analysis of Geometric Nonlinear Behavior of Suspension Bridges under Random Wind Loads (랜덤풍하중에 대한 현수교의 기하학적 비선형 거동의 동적해석)

  • Yun, Chung Bang;Hyun, Chang Hun;Yoo, Je Nam
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.8 no.2
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    • pp.185-196
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    • 1988
  • In this study, a method of nonlinear dynamic analysis of suspension bridges subjected to random wind loads is pre.sented. The nonlinearity considered is the one due to the interaction between the motion of the bridge girder and the tertsion variation of the main cables. The equation of motion is formulated using a continuum approach. The coupling between the vertical and torsional motions are included in the analysis. The equation of motion is solved by using the mode superposition method. The analysis is carried out in the frequency domain utilizing the stochastic linearization technique on to the modal equations. In the linearization procedure, the nonlinear terms are approximated as linear ones with constant terms. The verification of the method has been performed on a case with four modal degrees of freedom. Example analyses are carried out on two suspension bridges for various wind speeds and wind force parameters. Numerical results indicate that, by including the nonlinearity into the analysis, the dynamic responses of the bridges, particularly in the vertical direction, change considerably.

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A Nonlinear Finite Element Formulation for Very Large Deformation based on Updated Material Reference Frame (변화되는 재료의 기준 물성치에 근거한 매우 큰 변화에 대한 비선형 유한요소의 정식화)

  • Yun, Young Muk;Park, Moon Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.3
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    • pp.25-37
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    • 1992
  • A nonlinear finite element formulation which has the capability of handling very large geometrical changes is presented. The formulation is based on an updated material reference frame and hence true stress-strain test can be directly applied to properly characterize properties of materials which are subjected to very large deformation. For the large deformation, a consistent formulation based on the continuum mechanics approach is derived. The kinematics is referred to an updated material frame. Body equilibrium is also established in an updated geometry and the second Piola-Kirchhoff stress and the updated Lagrangian strain tensor are used in the formulation. Numerical examples for very large deformation of framed structures and plane solids are analyzed for verification purposes. The numerical solutions are obtained by an incremental numerical procedure. The importance of handing material properties properly is also demonstrated.

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