• Structural Engineering and Mechanics
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• 제65권5호
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• pp.505-511
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• 2018

Recently, a new foundation model called "Dynamic foundation model" was proposed for the dynamic analysis of structures on the foundation. This model includes a linear elastic spring, shear layer, viscous damping and the special effects of mass density parameter of foundation during vibration. However, the relationship of foundation property parameters with the experimental parameter of the influence of foundation mass also has not been established in previous research. Hence, the purpose of the paper presents a simple experimental model in order to establish relationships between foundation properties such as stiffness, depth of foundation and experimental parameter of the influence of foundation mass. The simple experimental model is described by a steel plate connected with solid rubber layer as a single degree of freedom system including an elastic spring connected with lumped mass. Based on natural circular frequencies of the experimental models determined from FFT analysis plots of the time history of acceleration data, the experimental parameter of the influence of foundation mass is obtained and the above relationships are also discussed.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2018년도 추계학술대회
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• pp.290-290
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• 2018

• 한국의류산업학회지
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• 제9권6호
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• pp.651-657
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• 2007

This study was carried out to analyse body configuration and to observe any space between skin and foundation. A special 3D scanner was used to analyze this foundation. Experimental foundations were brassiere, girdle, and all-in-one. Four subjects volunteered, each subject was scanned while wearing foundation and not wearing foundation. Body shape variations were analyzed with an Auto CAD and ScanWax program which analyzes cross section of the skin surface to look for any changes. Height was increased all parts of body, circumference was increased in breast and bust while wearing the foundation. The hip thickness was not increased with wearing the foundation. Therefore this foundation makes people have a different appearance due to unexpected body shape variations. The effects of this foundation should be classified by observing height, circumference, and thickness changes in the body.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.221-228
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• 2005

The economic growth brought the demand of bridge connected to island and land increasingly in Korea. Therefore, Civil engineer has faced a lot of problem to be considered such as structural stability, economic feasibility and constructional method. At the bridge site to be constructed, the depth of water is about 24m, the thickness of weathered rock overlaying bed rock is thicker than 36m. If open caisson foundation is supported in bed rock, the hight of foundation is about 60m. It is difficult to construct in these conditions. If open caisson foundation is supported in weathered rock, the size of the foundation should be increased. And If we apply the pile foundation, the higher construction cost will be needed. Under the circumstances, we need a new foundation type-composite foundation that is consisted of open caisson and cast-in-place piles. Because the design concept of composite foundation is not presented in Korea Bridge Design Standard, we are willing to clear the bearing behavior of composite foundation by numerical analysis in this paper.

• Geomechanics and Engineering
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• 제24권1호
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• pp.15-28
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• 2021

Digging well foundation has been widely used in railway bridges due to its good economy and reliability. In other instances, bridges with digging well foundation still have damage risks during earthquakes. However, there is still a lack of knowledge of lateral behavior of digging well foundation considering the soil-foundation interaction. In this study, scaled models of bridge pier-digging well foundation system are constructed for quasi-static test to investigate their lateral behaviors. The failure mechanism and responses of the soil-foundation-pier interaction system are analyzed. The testing results indicate that the digging foundations tend to rotate as a rigid body under cyclic lateral load. Moreover, the depth-width ratio of digging well foundation has a significant influence on the failure mode of the interaction system, especially on the distribution of foundation displacement and the failure of pier. The energy dissipation capacity of the interaction system is discussed by using index of the equivalent viscous damping ratio. The damping varies with the depth-width ratio changing. The equivalent stiffness of soil-digging well foundation-pier interaction system decreases with the increase of loading displacement in a nonlinear manner. The absolute values of the interaction system stiffness are significantly influenced by the depth-width ratio of the foundation.

• Earthquakes and Structures
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• 제21권6호
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• pp.641-652
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• 2021

Digging well foundation has been widely used in railway bridges due to its good economy and reliability. In other instances, bridges with digging well foundation still have damage risks during earthquakes. In this study, a new type of digging well foundation with prefabricated roots was proposed to reduce earthquake damage of these bridges. Quasi-static tests were conducted to investigate the failure mechanism of the root digging well foundation, and then to analyze seismic behaviors of the new type well foundation. The testing results indicated that these prefabricated roots could effectively limit the rotation and uplift of the digging well foundation and increase the lateral bearing capacity of the digging well foundation. The elastic critical load and ultimate load can be increased by 69% and 36% if prefabricated roots were added in the digging well foundation. The prefabricated roots drived more soil around the foundation to participate in working, the stiffness of the bridge pier with root digging well foundation was improved. Moreover, the root participation could improve the energy dissipation capacity of soil-foundation-pier interaction system. The conclusions obtained in this paper had important guiding significance for the popularization and application of the digging well foundation with prefabricated roots in earthquake-prone zones.

• Geomechanics and Engineering
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• 제34권6호
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• pp.649-664
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• 2023

Structural inertial interaction is a representative the effect of dynamic soil-foundation-structure interaction (SFSI), which leads to a relative displacement between soil and foundation, period lengthening, and damping increasing phenomena. However, for a system with a significantly heavy foundation, the dynamic inertia of the foundation influences and interacts with the structural seismic response. The structure-to-foundation mass ratio (MR) quantifies the distribution of mass between the structure and foundation for a structure on a shallow foundation. Although both systems exhibit the same vertical factor of safety (FS_v), the MR and corresponding seismic responses attributed to the structure and foundation masses may differ. This study explored the influence of MR on the permanent deformation and seismic response of soil-foundation-structure system considering SFSI via numerical simulations. Given that numerous dimensionless parameters of SFSI described its influence on the structural seismic response, the parameters, except for MR and FS_v, were fixed for the sensitivity analysis. The results demonstrated that the foundation inertia of heavier foundations induced more settlement due to sliding behavior of heavily-loaded systems. Moreover, the structural inertia of heavier structures evidently exhibited foundation rocking behavior, which results in a more elongated natural period of the structure for lightly-loaded systems.

• 벤처창업연구
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• 제9권1호
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• pp.51-67
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• 2014

본 연구는 우리나라 창업연구의 역사와 흐름의 파악을 통해 창업연구의 의미를 정확히 하는 것을 목적으로 하고 있다. 분석 기간은 IMF 이후 우리나라에 처음으로 벤처창업 붐이 일었던 1998년부터 가장 최근 논문인 2013년 9월까지이며 온라인으로 제공되고 있는 총 382편의 논문을 대상으로 종합적 메타분석 방법을 사용하였다. 분석은 창업연구분야, 창업지원분야, 창업단계분야, 창업기업형태분야, 창업가의 인구통계적 특성 등을 대상으로 실시하였으며 분석결과 다음과 같은 결론을 얻을 수 있었다. 첫째, 창업연구는 경영경제학 분야에서 활발히 전개되고 있으며 또한 산업 전반에 걸쳐 연구 대상이 되고 있다. 특히 IT산업분야, 외식산업분야, 콘텐츠산업분야 등은 창업에 대한 관심이 높게 나타나고 있다. 둘째, 창업지원 분야 중 주로 연구 대상이 되고 있는 것은 창업자, 창업교육, 외부환경 등이다. 셋째, 창업연구의 문제점으로 창업을 전략적, 세부적으로 파악하기보다 포괄적 관점에서 판단하고 있는 것이다. 넷째, 주요 창업연구 대상으로 기업형태로는 창업연구 발원기에 벤처기업 중심 연구가 주요 대상이었다가 최근에는 소상공인 창업 중심 연구가 활발히 진행되고 있으며, 창업자 특성 측면에서는 전 기간에 걸쳐 대학생을 포함한 청년 창업이 주된 연구 대상이 되고 있는 상황에서 최근 시니어 창업에 대한 관심이 높아지고 있다. 이상의 연구를 바탕으로 향후 창업연구 활성화를 위해 창업연구는 보편적 창업연구의 활성화, 산업적 특수성이 반영된 창업연구, 융합연구의 활성화 등이 이루어져야 한다.

• Structural Engineering and Mechanics
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• 제59권6호
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• pp.1019-1035
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• 2016

This paper proposes a new foundation model called "Dynamic foundation model" for the dynamic analysis of plates on foundation subjected to a moving oscillator. This model includes a linear elastic spring, shear layer, viscous damping and the special effects of mass density parameters of foundation during vibration. By using finite element method and the principle of dynamic balance, the governing equation of motion of the plate travelled by the oscillator is derived and solved by the Newmark's time integration procedure. The accuracy of the algorithm is verified by comparing the numerical results with the other numerical results in the literature. Also, the effects of mass and damping ratio of system components, stiffness of suspension system, velocity of moving oscillator, and dynamic foundation parameters on dynamic responses are investigated. A very important role of these factors will be shown in the dynamic behavior of the plate.

• Coupled systems mechanics
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• 제12권1호
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• pp.83-102
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• 2023

First introduced in 2016, the dynamic foundation model is an interesting topic in which the foundation is described close to reality by taking into account the influence of the foundation mass in the calculation of oscillation and is an important parameter that should be considered. In this paper, a follow-up investigation is conducted with the object of the Mindlin plate on a nonlinear dynamic foundation under moving loads. The base model includes nonlinear elastic springs, linear Pasternak parameters, viscous damping, and foundation mass. The problem is formulated by the finite element analysis and solved by the Newmark-β method. The displacement results at the center of the plate are analyzed and discussed with the change of various parameters including the nonlinear stiffness, the foundation mass, and the load velocity. The dynamic response of the plate sufficiently depends on the foundation mass.