• Title/Summary/Keyword: 자유보

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Historical Changes of Incheon Freedom Park and Its Heritage Value Interpretation as the Historic Urban Public Park (인천 자유공원의 역사적 변천과 역사도시공원으로서의 유산 가치 해석)

  • Kim, Soon-Ki
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.41 no.4
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    • pp.30-39
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    • 2023
  • This study aims to identify the value of Incheon Freedom Park as a 'historic urban park' through the historical transition process of the park and surrounding areas. To this end, this study uses a time series analysis, as research method, based on old maps and aerial photographs to investigate the changes in the park over time and to interpret them based on the historical and cultural changes in modern and contemporary history. As a result of the study, the park not only has (1) evidence of major events in modern and contemporary history, but also (2) historical value as an urban park based on the first urban plan in Korea, and (3) very important heritage value that shows the rapidly changing civic life in modern and contemporary times. However, despite the identification of heritage values in this study, further research is needed to explore and excavate in-depth data on the park in order to more clearly identify, restore, and utilize the heritage values of the park.

Free Vibrations and Buckling Loads of Beam-Columns on Winkler-Type Foundations (Winkler형 지반위에 놓인 보-기둥의 자유진동 및 좌굴하중 해석)

  • Jeong, Jin Seob;Lee, Byoung Koo;Oh, Sang Jin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.4
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    • pp.251-258
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    • 1993
  • The main purpose of this paper is to present both the natural frequencies and the buckling loads of beam-columns on Winkler-type foundations. The ordinary differential equations governing the free vibrations and the buckling loads of beam-columns on Winkler-type foundation are derived as nondimensional forms. The Runge-Kutta method and Determinant Search method are used to perform the integration of the differential equations and to determine the eigenvalues(natural frequencies and buckling loads), respectively. Hinged-hinged and damped-clamped end constraints are applied in numerical examples. The relation between frequency parameter and elastic foundation parameter is presented in figure. The effects of axial loads on the natural frequencies of beam-columns on elastic foundations are investigated and the relation between buckling load parameter and elastic foundation parameter is also analyzed. The relation between foundation rested ratio and frequency parameter, buckling load parameter are investigated. The beam-columns on non-homogeneous elastic foundation are analyzed and typical mode shapes are also presented.

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A Study on the Vibration and Acoustic Radiation from an Elastic Free- Free Beam due to a Steel Ball Impact (강구의 충돌에 의한 양단자유 보의 진동 및 음향 방사에 관한 연구)

  • 박홍철;이효근;박윤식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.9
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    • pp.1615-1626
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    • 1992
  • In this study, vibrations and resulting acoustic radiations from an elastic beam impacted by a steel ball were studied theoretically and experimentally. First the transverse vibrations of free-free elastic beams are analysed with modal analysis technique. The impact forces are modeled with the Hertz's theory and the contanct duration is compared with the measured values. Also the calculated beam vibrations are verified with the experimental results. Then the acoustic radiations due to the beam vibration are studied numberically and experimentally. The acousticpressure is calculated assuming the beam has an elliptical cross-section. The predicted acoustic pressure is compared with the measured value. It was found that both the predicted beamvibrations using the Hertz's theory and the estimated acoustic pressure under the assumption of an elliptical cross- section are in very good agreements with the measured values.

Experimental Study on Establishment of Downstream Critical Depth in Round-Crested Weir (보 하류부 임계수심 설정에 관한 실험적 연구)

  • Yeo Hong Gu;Kang Joon Gu;Cheong Sang Hwa;Yoon Byeong Mo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2005.05b
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    • pp.1113-1117
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    • 2005
  • 보 상류의 유속 및 수심과 같은 흐름 조건은 보, 하천 형상, 그리고 하류 흐름 특성에 의해 좌우된다. 본 연구에서는 하류 조건에 따라 보 상류의 흐름 특성에 미치는 영향을 검토하였다. 이를 위해 구형단면의 수로에 하천설계지침(2002)에 따라 보를 제작하여 설치하였으며 보에서의 임계수심 및 이에 따른 유량의 변화를 파악하였으며 실험결과를 기존 문헌과 비교$\cdot$분석하였다. 또한 자유 월류로 빠른 유속을 지닌 흐름이 수로의 마찰저항과 하류 배수효과에 의해 에너지 소멸로 나타나는 도수현상을 관측하여 발생특성을 파악하였다. 도수의 발생조건은 Posey와 Hsing(1938)에 제시한 결과와 유사한 결과를 보였으며 하류영향에 따른 도수 발생 위치는 하류단 수위와 일정한 관계를 갖고 있으나 유량과는 선형적인 관계를 보이지 않는 것을 알 수 있었다. 또한 임계수심 설정에 대해 Knap(1960)이 제시한 산정식과 비교한 결과 유량이 작은 경우 거의 일치하는 결과를 보였으나 유량이 증가할수록 오차가 커졌다. 임계수심 전$\cdot$후의 유량계수를 살펴본 결과 하류 조건에 의해 임계수심을 넘으면 유량계수가 자유 월류 시보다 약 $2\%\~6.5\%의 감소를 나타냈으며 공급유량이 $0.05m^3/s$ 일 경우 유량계수의 차이가 가장 큰 것을 알 수 있다.

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Improved Curved Beam Theory for Vibration and Deflection Analyses (진동 및 처짐해석을 위한 개선된 곡선보이론)

  • Kim, Nam-Il;Choi, Jung-Ho
    • Journal of Korean Association for Spatial Structures
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    • v.10 no.4
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    • pp.123-132
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    • 2010
  • To overcome the drawback of currently available curved beam theories having non-symmetric thin-walled cross sections, a curved beam theory based on centroid-shear center formulation is presented for the spatially coupled free vibration and elastic analyses. For this, the displacement field is expressed by introducing displacement parameters defined at the centroid and shear center axes, respectively. Next the elastic strain and kinetic energies considering the thickness-curvature effect and the rotary inertia of curved beam are rigorously derived by degenerating the energies of the elastic continuum to those of curved beam. In order to illustrate the validity and the accuracy of this study, FE solutions using the Hermitian curved beam elements are presented and compared with the results by centroid formulation, previous research and ABAQUS's shell elements.

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New DNA of the Korean welfare state: Towards social liberalism and freecurity (한국 복지국가의 새로운 DNA: 사회적 자유주의와 자유안정성을 향하여)

  • Choi, Young Jun
    • 한국사회정책
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    • v.25 no.4
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    • pp.39-67
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    • 2018
  • The Korean welfare state has achieved remarkable development during the last two decades, but simultaneously we have witnessed growing prevalent social conflicts and exclusion in the society. This research argues that the source of current problems lies in the nature of the Korean welfare regime, so called, 'paternalistic liberalism'. The paternalistic liberalism has been formulated by the combination of legacies of the developmental state and neo-liberalism. Paternalism with the growth-oriented and employment-centered approach has been a significant factor to restrict individuals' freedom and happiness in the Korean welfare state. It has also been embedded in the Korean welfare state such as social insurance, workfare programs, and centralized social services. In this context, this research proposes social liberalism, pursuing real freedom for all, as a new paradigm for the Korean welfare state. Breaking from the old path, Freecurity, combining freedom and security, which is argued to be the upgraded version of flexicurity, is also newly proposed as the operating model of social liberalism.

Determination of Dynamic Free Span Length for Subsea Pipelines with General Boundary Conditions (일반화된 경계조건을 갖는 해저파이프라인의 동적 자유경간 결정 방법)

  • 박한일
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.13 no.4
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    • pp.290-295
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    • 2001
  • Subsets pipelines are exposed to several potential risks of damage due to corrosion, soil instability, anchor impact and other hazards. One of the main risk factors for the safety of a subsea pipeline is its free spanning. This paper examines the safety of subsea pipelines with free span under axial compressive load. The variation of allowable lengths of dynamic free span is examined for generalized boundary conditions. The free span is modelled as a beam with an elastic foundations and the boundary condition is replaced by linear and rotational springs at each end. A dynamic free span curve is obtained with a function of non-dimensional parameters and can be used usefully for the design of subsea pipelines with a free span. A case study is carried out to introduce the application method of the curve.

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The Problem of Freedom: Merleau-Ponty and Sartre (자유의 문제: 메를로-퐁티와 사르트르)

  • Sim, Gui-yeon
    • Journal of Korean Philosophical Society
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    • v.123
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    • pp.165-187
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    • 2012
  • Our freedom is natural, however we are amazed at the fact that we don't sometimes have the freedom. we have to have a freedom and must be a freedom. But we think our life is restrained. Why do we think that? This is due to epistemological thinking. Also critic of Sartre' freedom is due to that. Especially Merleau-Ponty's researchers say that Sartre is an epistemologist on the problem of the freedom and his freedom is an absolute freedom. Aim of this paper is to find out problem of the critic. To achieve this, first we need to exmaine what absoulte freedom is. It is abstract and ideological. According to Merleau-Ponty, it dosen't exist. This paper argues that Sartre's freedom is not epistemoligical but ontological. It is going to come out in relation between '$l^{\prime}{\hat{e}}tre-en-soi$' and '$l^{\prime}{\hat{e}}tre-en-soi$'. Then, on the problem of the freedom, we can discover that Sartre and Merleau-Ponty are no different from each other. Finally, As I argue about Merleau-Ponty's freedom, I will show that it is 'a freedom of situation' and 'a freedom of choice'. Also, This freedom is Sartre's freedom. Sartre showes a situation is my freedom.

New Curved Beam Elements Including Shear Effects (전단 효과를 고려한 새로운 곡선보 요소)

  • 최종근;임장근
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.3
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    • pp.751-756
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    • 1991
  • 본 연구에서는 Ashwell이 제시한 변형률요소를 전단효과를 고려한 두꺼운 곡 선보 요소에 적용 하였다. 막 변형률, 곡률, 전단변형률 각각에 독립된 변형률 함수 를 가정하여 미분 방정식의 일반해를 구하면 정확한 강체변위의 표현은 물론, 강성과 잉현상을 피할 수 있고 얇은 곡선보에서 두꺼운 곡선보에 이르기까지 보의 해석에 있 어서, 2절점으로 구성되는 적은 자유도수에서 높은 정확도를 보여주는 간편하고도 효 율적인 요소를 개발하고자 하였다.

Free Vibration Analysis of Multi-Delaminated Beams (다층 층간분리된 적층보의 자유진동해석)

  • 이성희;박대효;백재욱;한병기
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.14 no.4
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    • pp.469-479
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    • 2001
  • In the present study, free vibration analysis of multi-delaminated beams is performed. In order to investigate the effects of mu1ti-delaminations on the dynamic characteristics of multi-delaminated beams, the general kinematic continuity conditions are derived from the assumption of constant curvature at the multi-delamination tip. Frequency equations of multi-delaminated beams are obtained by dividing the global multi-delaminated beam into beam segments and by imposing recurrence relation from the continuity conditions un each sub-beam. The comparisons between the results of numerical analysis obtained by finite element analysis and those of present analysis give good agreement with each other. It is shown that the effects of multi-delaminations on free vibration characteristics of laminated beams could be used to detect their sizes, types and locations from the results.

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