• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.3-10
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• 2004

This study set out to analyze the appropriateness of the piling distance installed in weathered layer in the auger-drilled piling method and the reasonable piling distance for the unfinished parts. For that purpose, an investigation was done of the reliability of the dynamic test, the appropriateness of the old bearing capacity formula for the auger-drilled piling, and the quality control measures for obtaining the required bearing capacity.

• 대한전자공학회논문지
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• 제26권12호
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• pp.1934-1939
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• 1989

The circular microstrip resonator which can be exactly performed with theoretical resonant frequency using the conception of dynamic effective relative dielectric constants is analyzed in this paper. The formula of exact resonant frequency of resonator, in this study, is estabilished by effective resonator dimension and dynamic relative dielectric constant. The measurement of transmission type circular resonator which fabricated by AL2O3 and Epsilam-10 is to prove that the experimental results are more agreed a well with the simulated values by this new method than the simple resonator model.

• 식품보건융합연구
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• 제8권1호
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• pp.21-30
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• 2022

This study proposed a multiple regression equation for predicting VO2max of elderly men and women using functional performance variables required to conduct daily activities. The subjects of this study were 58 elderly men (72.4±5.9 yrs) and 117 elderly women (73.4±4.5 yrs) aged 65-90 who belong to the senior welfare center. The maximal graded exercise test using a cycle ergometer and functional performance representing muscle strength, endurance, static and dynamic flexibility, mobility, and agility were measured. For statistical processing, multiple regression analysis was performed, and the statistical significance level was α = .05. As a result, the VO2max estimation formula for the elderly was 0.419 (standing up and sitting down a chair) + 0.199 (leg endurance against wall) + 5.383, and R2=0.406. In addition, the VO2max estimation formula for elderly women is - 0.737 (standing up from a supine position) - 0.144 (waking around two cones in a figure 8) - 0.135 (%body fat) + 0.042 (one leg balance with eyes open) + 29.395, R2=0.367 was calculated. The conclusion is that if the maximal graded exercise test is not available, it is considered that VO2max of the elderly can be predicted properly by using the estimation formula calculated based on the functional performance variable.

• 한국수자원학회논문집
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• 제38권12호
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• pp.1029-1037
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• 2005

본 연구는 도시 우수관망 설계 시 주어진 설계유량을 효율적이고 경제적인 단면 구성과 관망에 따른 우수배제 능력을 극대화시키기 위해 최적화 기법인 동적계획법(Dynamic Programming : DP)의 특수한 방법인 이산미분형 동적계획법(Discrete Differential Dynamic programming DDDP)를 이용해 최적화된 설계조건을 구할 수 있도록 하였다. 이산미분형 동적계획법의 기법은 설계유량과 맨홀의 위치가 결정되면 그에 따른 최적 우수시스템이 될 수 있는 관의 용량, 경사, 수위, 수심, 위험도, 회수비용 등을 결정할 수 있는 방법으로 이는 공사비용에 따를 최소비용을 목적함수로 위험도 분석을 통하여 최적화된 조건을 찾는 방법으로 모형개발을 하였다. 개발된 모형을 실제 단지계획의 합리식으로 설계된 우수관망 계획과 비교 검증하여 보다 경제적이고 효율적인 우수관망 시스템을 구축하는 모형을 제시하였다.

• 한국정밀공학회지
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• 제31권10호
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• pp.897-904
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• 2014

In this paper, two-DOF parallel manipulator has the sliders which execute a linear reciprocating motion depending on parallel guides and the end-effector which can be adjusted arbitrarily. To investigate the dynamic characteristics of the manipulator, the dynamic performance index is used. The index is able to be obtained by the relation between the Jacobian matrix and the inertia matrix. The kinematic and the dynamic analysis find these matrices. Also, the dynamic model of the manipulator is derived from the Lagrange formula. This model represents complicated nonlinear equations of motion. With the simulation results of the dynamic characteristic of the manipulator, we find that the dynamic performance index is based on the selection of the ranges for the continuous movement of the manipulator and the dynamic model derived can be used to the control algorithm development of the manipulator.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1998년도 가을 학술발표회 논문집
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• pp.191-198
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• 1998

• Steel and Composite Structures
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• 제21권1호
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• pp.109-122
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• 2016

Concrete creep, while significantly changing the static behaviors of concrete filled steel tube (CFST) structures, do alter the structures' dynamic behaviors as well, which is studied quite limitedly. The attempt to investigate the influence of concrete creep on the dynamic property and response of CFST arch bridges was made in this paper. The mechanism through which creep exerts its influence was analyzed first; then a predicative formula was proposed for the concrete elastic modulus after creep based on available test data; finally a numerical analysis for the effect of creep on the dynamic behaviors of a long-span half-through CFST arch bridge was conducted. It is demonstrated that the presence of concrete creep increases the elastic modulus of concrete, and further magnifies the seismic responses of the displacement and internal force in some sections of the bridge. This influence is related closely to the excitation and the structure, and should be analyzed case-by-case.

• 한국자동차공학회논문집
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• 제7권6호
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• pp.135-143
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• 1999

This investigation evaluates effects of notch depth, fatigue precrack length and side groove in impact specimen for estimation of a valid K1d by instrumented Charpy impact test. Specimen material is 6005-T6. for notch depth 2.0mm and 2.5mm specimens or within about 2mm fatigue precrack length with notch depth 2.0mm and 2.5mm specimens or within about 2mm fatigue precrack length with notch depth 2.0mm , dynamic fracture toughness [$K_{1d,(1)}$] obtained by crack initiation load($P_m$) should be used. Dynamic fracture toughness of side grooved specimens are overestimated to that of standard impact specimen about 15 %-20%. It is confirmed that the formula of dynamic fracture toughness obtained by impact absorbed energy is inappropriate for ductile materials.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권3호
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• pp.685-699
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• 2014

In this study, the dynamic responses of a riser under the combined excitation of internal waves and background currents are studied. A modified Taylor-Goldstein equation is used to calculate the internal waves vertical structures when background currents exist. By imposing rigid-lid boundary condition, the equation is solved by Thompson-Haskell method. Based on the principle of virtual work, a nonlinear differential equation for riser motions is established combined with the modified Morison formula. Using Newmark-${\beta}$ method, the motion equation is solved in time domain. It is observed that the internal waves without currents exhibit dominated effect on dynamic response of a riser in the first two modes. With the effects of the background currents, the motion displacements of the riser will increase significantly in both cases that wave goes along and against the currents. This phenomenon is most obviously observed at the motions in the first mode.

• Structural Engineering and Mechanics
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• 제91권4호
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• pp.403-416
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• 2024

The single-column pier girder bridge, due to its low engineering cost, small footprint, and aesthetic appearance, is extensively employed in urban viaducts and interchange ramps. However, its structural design makes it susceptible to eccentric loads, flexural-torsional coupling effects, and centrifugal forces, among others. To evaluate its anti-overturning performance reasonably, it is crucial to determine the reaction force of the support for the single-column pier girder bridge. However, due to the interaction between vehicle and bridge and the complexity of vibration modes, it poses a significant challenge to analyze the theory or finite element method of single-column pier girder bridges. The unit load bearing reaction coefficient method is proposed in this study to facilitate the static analysis. Numerous parameter analyses have been conducted to account for the dynamic amplification effect. The results of these analyses reveal that the dynamic amplification factor is independent of road surface roughness but is influenced by factors such as the position of the support. Based on parameter analysis, the formula of the dynamic amplification factor is derived by fitting.