• 인문언어
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• 제5권
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• pp.7-36
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• 2003

In this paper I am arguing in favour of more vigilance on the part of the Korean linguistics' melieu and, if deemed necessary, a more solid epistemological foundation of the Korean Linguistics. The purpose of this work consist in providing some epistemological inquiry on the major orientations and tendencies which are manifested in the reception of western linguistic theories. I might call this point of view as a critical approach to the philosophy and history of Korean linguistics. In the first section, I gave a short description of the model of the linguistic historiography which can be applied to the history of the Korean linguistics. In the second section, I am concerned with the comparative epistemology of the development of linguistic ideas produced in the West and East. In the final section, I made some critical reflections on the limits of Korean linguistics.

• Composites Research
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• 제27권6호
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• pp.207-212
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• 2014

The shape optimization of composite flexbeam sections of a bearingless helicopter rotor is studied using a finite element (FE) sectional analysis integrated with an efficient evolutionary optimization algorithm called particle swarm assisted genetic algorithm (PSGA). The sectional optimization framework is developed by automating the processes for geometry and mesh generation, and the sectional analysis to compute the elastic and inertial properties. Several section shapes are explored, modeled using quadratic B-splines with control points as design variables, through a multiobjective design optimization aiming minimum torsional stiffness, lag bending stiffness, and sectional mass while maximizing the critical strength ratio. The constraints are imposed on the mass, stiffnesses, and critical strength ratio corresponding to multiple design load cases. The optimal results reveal a simpler and better feasible section with double-H shape compared to the triple-H shape of the baseline where reductions of 9.46%, 67.44% and 30% each are reported in torsional stiffness, lag bending stiffness, and sectional mass, respectively, with critical strength ratio greater than 1.5.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.801-804
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• 2006

The purpose of this paper is to investigate the stability of stepped cantilever columns with a tip mass of rotatory inertia and a translational spring at one end. The column model is based on the Bernoulli-Euler theory which neglects the effects of rotatory inertia and shear deformation. The governing differential equation for the free vibration of columns with stepwise variable cross-section and subjected to a subtangential follower force is solved numerically using the corresponding boundary conditions. And the bisection method is used to calculate the critical divergence/flutter load. The frequency and critical divergence/flutter load for the stepped column with a single step are presented as functions of various non-dimensional system parameters: the segmental length parameter, the section ratio, the subtangential parameter, the mass, the moment of inertia of the mass, and the spring parameter.

• 한국방재학회 논문집
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• 제2권4호
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• pp.131-141
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• 2002

지하주차장을 PC화할 때 각각의 부재 접합상태에 따라 설계방법 및 시공방법에 많은 차이가 발생하게 된다. 특히 PC 벽체를 상호 연결하기 위한 접합부에서 수평철근을 겹침이음 방법에 의해 접합하는 경우, 수평철근의 이음길이를 충분히 확보하여야 하기 때문에 시공성이 저하되는 문제점이 있다. 따라서, PC 벽체 수평철근의 돌출길이를 최소화하기 위하여 철근 비부착 기법 및 철근 절단 기법을 적용하는 것을 본 연구의 목적으로 하고 있다. 즉, 철근 콘크리트 부재에서의 위험단면의 위치는 일반적으로 부재의 단부가 되고, 철근의 정착길이는 이 위험단면으로부터의 길이가 된다. 그런데 위험단면의 위치를 비부착 철근 공법 및 철근 절단 공법을 사용하여 부재 안쪽으로 이동함으로서, 수평철근의 정착길이를 최소화시킬 수 있다. 본 연구에서는 철근 비부착 기법 및 철근 절단 기법의 적용 가능성을 파악하기 위해 5개의 실험체를 실물크기로 제작하여 실험적 연구를 실시하고, 절단 철근 및 비부착 철근이 시험체의 거동에 미치는 영향을 비교 및 분석한 결과, 위험단면의 이동을 위하여 철근 비부착 기법 및 철근 절단 기법의 사용이 가능한 것으로 판단된다.

• Structural Engineering and Mechanics
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• 제43권4호
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• pp.459-473
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• 2012

Post-tensioned concrete voided slab girders are widely used in highway bridge constructions. To obtain greater section hollow rate and reduce the self-weight, the plate thickness of slab girders are designed to be small with the adoption of flat anchorage system. Since large prestress is applied to the anchor end section, it was found that longitudinal shear cracks are easy to occur along the voided slab girder. The reason is the existence of great shearing effect at the junction area between web and bottom (top) plate in the anchor end section. This paper focuses on the longitudinal anti-cracking problem at the anchor end of post-tensioned concrete voided slab girders. Two possible models for longitudinal anticracking analysis are proposed. Differential element analysis method is adopted to derive the solving formula of the critical cracking state, and then the practical analysis method for longitudinal anti-cracking is established. The influence of some factors on the longitudinal anti-cracking ability is studied. Results show that the section dimensions (thickness of bottom, web and top plate) and prestress eccentricity on web plate are the main factors that influence the anti-cracking ability. Moreover, the proposed method is applied into three engineering examples to make longitudinal anti-cracking verification for the girders. According to the verification results, the design improvements for these girders are determined.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.447-452
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• 2000

In this study, the design of Free-Fall Simulator was carried out using concept of vertical wind tunnel. Free-Fall Simulator is not an experimental equipment but a training equipment. Therefore Free-Fall Simulator needs a large training section compared with test section of wind tunnel and has critical limit of height. These limits bring about the difficulty of design for a return passage. Due to small area ratio, the downstream flow of training section with high speed is not decelerated adequately to the fan section. High-speed flow leads to great losses in the small area ratio diffuser and corner. So design of diffusers and corners located between training section and fan section has a great effect on the Free-Fall Simulator performance. This study used an estimation method of subsonic wind tunnel performance. It considered each section of Free-Fall Simulator as an independent section. Therefore loss of one section didn't affect loss of other sections. Because losses of corner with vane and $1^{st}$ diffuser are most parts of overall Free-Fall Simulator, this study focused on the design of these sections.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.963-968
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• 2006

The main purpose of this paper is to investigate the stability of water tower with a relatively small footing. The water tower is modeled that the column carrying a container is supported by a rotational spring at the base and is of constant cross-section, with a weight per unit length of column axis. The column model is based on the Bernoulli-Euler beam theory. The Runge-Kutta method and Determinant Search method are used to perform the integration of the governing differential equation and to determine the critical values(critical own weight. and critical buckling load), respectively. The critical buckling loads are calculated over a range of system parameters: the rotational stiffness parameter, the dimensionless radius of container and the own weight parameter of the column. The relation between the rotational stiffness parameter and the critical own weight parameter of the column is analyzed.

• International Journal of Reliability and Applications
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• 제15권2호
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• pp.99-110
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• 2014

Based on the kernel function, a new test is presented, testing $H_0:\bar{F}$ is exponential against $H_1:\bar{F}$ is UBACT and not exponential is given in section 2. Monte Carlos null distribution critical points for sample sizes n = 5(5)100 is investigated in section 3. The Pitman asymptotic efficiency for common alternatives is obtained in section 4. In section 5 we propose a test statistic for censored data. Finally, a numerical examples in medical science for complete and censored data using real data is presented in section 6.

• Wind and Structures
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• 제6권4호
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• pp.263-278
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• 2003

This study investigates the effects of a bridge deck's width-to-depth (B/H) ratio and turbulence on buffeting response and flutter critical wind speed of long-span bridges by conducting section model tests. A streamlined box section and a plate girder section, each with four B/H ratios, were tested in smooth and turbulent flows. The results show that for the box girders, the response increases with the B/H ratio, especially in the vertical direction. For the plate girders, the vertical response also increases with the B/H ratio. However, the torsional response decreases as the B/H ratio increases. Increasing the B/H ratio and intensity of turbulence tends to improve the bridge's aerodynamic stability. Experimental results obtained from the section model tests agree reasonably with the calculated results obtained from a numerical analysis.

• Steel and Composite Structures
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• 제18권3호
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• pp.603-621
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• 2015

In this study, theoretical models and design procedures of the behavior of thin-walled simply supported steel beams with an open cross section under a large torsional effect are presented. I-sections were chosen as the cross section types. Firstly, the widely used differential equations for the lateral buckling for the pure bending moment effect in a beam element were adopted for the various moment distributions along the span of the beam. This solution was obtained for both mono-symmetric and bisymmetric sections. The buckling loads were then obtained by using the energy method. When using the energy method to solve the problem, it is possible to locate the load not only on the shear center but also at several points of the section depth. Buckling loads were obtained for six different load types. Results obtained for different load and cross section types were checked with ABAQUS software and compared with several standard rules.