• 한국전산구조공학회논문집
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• 제13권4호
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• pp.437-448
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• 2000

본 연구에서는 외부의 동하중에 의한 다층 지반-말뚝 상호작용계의 해석을 위한 동적 유한요소-경계요소 조합 주파수 응답해석 알고리즘을 개발하였다. 전체 상호작용계를 내부영역과 외부영역으로 나누고, 내부영역에 보요소를 도입하여 말뚝을 모형화 하고 평면변형률 요소로 모형화된 지반과 조합하였다. 말뚝머리 절점에 집중질량을 이용하여 상부구조물을 고려하므로써 전체 지반-말뚝 상호작용계의 내부영역을 형상화하였다. 외부영역에 동적 기본해를 이용한 경계요소 해석을 도입하고 유한요소로 구성된 내부영역과 조합하므로써 반무한체에 대한 방사조건을 만족시키고 내부의 복잡한 기하학적 성질과 다양한 물성의 고려가 가능한 수치해석 기법을 개발하였다. 개발된 지반-말뚝-구조물계의 상호작용 해석법에 대한 타당성을 알아보기 위해 다층반무한 지반에 근입되어진 말뚝에 조화하중을 가하여 동적 응답해석을 실시하고 기존의 연구결과 및 실험값과 비교 검증하였다. 또한 상호작용계의 주요 인자들의 변화를 통한 다양한 해석을 수행하므로써 다층 반무한 지반에 근입되어진 말뚝의 동적 특성을 고찰하였다.

• Molecules and Cells
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• 제26권1호
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• pp.100-105
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• 2008

Glycogen synthase kinase $3{\beta}$ (GSK $3{\beta}$) is a serine/threonine kinase that phosphorylates substrates such as ${\beta}$-catenin and is involved in a variety of biological processes, including embryonic development, metabolism, tumorigenesis, and cell death. Here, we present evidence that human GSK $3{\beta}$ is associated with Fe65, which has the characteristics of an adaptor protein, possessing a WW domain, and two phosphotyrosine interaction domains, PID1 and PID2. The GSK $3{\beta}$ catalytic domain also contains a putative WW domain binding motif ($^{371}PPLA^{374}$), and we observed, using a pull down approach and co-immunoprecipitation, that it interacts physically with Fe65 via this motif. In addition, we detected co-localization of GSK $3{\beta}$ and Fe65 by confocal microscopy, and this co-localization was disrupted by mutation of the putative WW domain binding motif of GSK $3{\beta}$. Finally, in transient transfection assays interaction of GSK $3{\beta}$ (wt) with Fe65 induced substantial cell apoptosis, whereas interaction with the GSK $3{\beta}$ AALA mutant ($^{371}AALA^{374}$) did not, and we noted that phosphorylation of the Tyr 216 residue of the GSK $3{\beta}$ AALA mutant was significantly reduced compared to that of GSK $3{\beta}$ wild type. Thus, our observations indicate that GSK $3{\beta}$ binds to Fe65 through its $^{371}PPLA^{374}$ motif and that this interaction regulates apoptosis and phosphorylation of Tyr 216 of GSK $3{\beta}$.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 춘계 학술발표회 논문집
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• pp.125-132
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• 2002

In this study, a numerical method is developed for nonlinear analysis for soil-pile-structure interaction system in time domain. Finite elements considering material nonlinearity are used for the near field and boundary elements for the far field. In the near field, frame elements are used for modeling a pile and plane-strain elements for surrounding soil and superstructure. In. the far field, boundary element formulation using the dynamic fundamental solution is adopted and coupled with the near field. Transformation of stiffness matrices of boundary elements into time domain is performed by inverse FFT. Stiffness matrices in the near field and far field are coupled. Newmark direct time integration method is applied. Developed soil-pile-structure interaction analysis method is verified with available literature and commercial code. Also, parametric studies by developed numerical method are performed. And seismic response analysis is performed using actual earthquake records.

• Structural Engineering and Mechanics
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• 제21권1호
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• pp.101-119
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• 2005

An efficient methodology is presented to evaluate the seismic behavior of a Fluid-Elevated Tank-Foundation/Soil system taking the embedment effects into accounts. The frequency-dependent cone model is used for considering the elevated tank-foundation/soil interaction and the equivalent spring-mass model given in the Eurocode-8 is used for fluid-elevated tank interaction. Both models are combined to obtain the seismic response of the systems considering the sloshing effects of the fluid and frequency-dependent properties of soil. The analysis is carried out in the frequency domain with a modal analysis procedure. The presented methodology with less computational efforts takes account of; the soil and fluid interactions, the material and radiation damping effects of the elastic half-space, and the embedment effects. Some conclusions may be summarized as follows; the sloshing response is not practically affected by the change of properties in stiff soil such as S1 and S2 and embedment but affected in soft soil. On the other hand, these responses are not affected by embedment in stiff soils but affected in soft soils.

• Coupled systems mechanics
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• 제3권4호
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• pp.385-403
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• 2014

In this paper, the forced vibration problem of an Euler-Bernoulli beam that is joined with a semi-infinite field of a compressible fluid is considered as a boundary value problem (BVP). This BVP includes two partial differential equations (PDE) and some boundary conditions (BC), which are introduced comprehensively. After that, the closed-form solution of this fluid-structure interaction problem is obtained in the frequency domain. Some mathematical techniques are utilized, and two unknown functions of the BVP, including the beam displacement at each section and the fluid dynamic pressure at all points, are attained. These functions are expressed as an infinite series and evaluated quantitatively for a real example in the results section. In addition, finite element analysis is carried out for comparison.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.106-113
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• 2002

In this study, a numerical analysis method for soil-pile interaction in frequency domain problem is presented. The total soil-pile interaction system is divided into two parts so called near field and far field. In the near field, beam elements are used for a pile and plain strain finite elements for soil. In the far field, dynamic fundamental solution for multi-layered half planes based on boundary element formulation is adopted for soil. These two fields are coupled using FE-BE coupling technique In order to verify the proposed soil-pile interaction analysis, the dynamic responses of pile on multi-layered half planes are simulated and the results are compared with the experimental results. Also, the dynamic response analyses of interface spring elements are performed. As a result, less spring stiffness makes the natural frequency decrease and the resonant amplitude increase.

• 제어로봇시스템학회논문지
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• 제12권5호
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• pp.457-463
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• 2006

Recently proposed control scheme for a stable teleoperation, which was based on two-port time-domain passivity approach[21], has been successful for a contact with high stiffness environments. However, we found several conservatisms during the contact with deformable environments and unconstrained motion. The two-port time-domain passivity controller was excessively dissipating energy even though it was not necessary for some cases of an unconstrained motion and soft contact. The main reason of those conservatisms was on the fact that the two-port time-domain passivity controller was activated without considering the amount of energy dissipation at the master and slave manipulators. Especially, the exclusion of the slave manipulator from the two-port was the dominant reason of the conservatisms. In this paper, we consider the amount of energy dissipation at slave manipulator for designing the time-domain passivity observer and controller. The measured interaction force between slave manipulator and environment allow the time-domain passivity observer to include the amount of energy dissipation at the slave manipulator. Based on the modified passivity observer, reference energy following method[24] is applied to satisfy the passivity condition in real-time. The feasibility of the developed methods is proved with experiments. Improved performance is obtained for an interaction with deformable environments and an unconstrained motion.

• 한국비블리아학회지
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• 제30권2호
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• pp.145-166
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• 2019

정보행태 연구 커뮤니티에서 그간 다수의 이용자 관련 모형들이 제시되어온바, 본 연구의 출발점은 정보검색 상호작용 모형을 포함한 대부분의 모형들이 포괄적 영역을 제시하는 다(多)영역 모형이라는 점이다. 본 연구는 다 영역 모형의 제한점을 논의한 후, 새로운 모형 유형 제시의 필요성을 제기한다. 이와 관련, 연구 커뮤니티내의 핵심 모형 네 가지를 분석 고찰한 후, 특정영역 초점 모형화(Specific Domain Focus Modeling - SDFM)에 기반한 새로운 모형 유형을 제시한다. 이러한 모형화의 예로써, 본 연구는 필자의 시스템-자료 군 연계정도 기반 정보검색 상호작용 모형을 제시한다.

• 한국지진공학회논문집
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• 제14권5호
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• pp.1-12
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• 2010

본 연구에서는 얕은 연약지반에서 구조물-지반 상호작용의 영향을 받는 구조물의 비탄성거동을 정확히 나타낼 수 있는 유한요소해석 방법을 연구하였다. 이를 위하여, 국내의 지반특성을 반영한 얕은 연약지반과 단자유도 구조물로 2차원 유한요소모델을 구성하고, 다양한 지진파와 지반에 대해 OpenSees 해석프로그램을 이용한 비선형 시간이력해석을 수행하였다. 연약지반의 비선형거동을 반영하기 위하여 일반적으로 흔히 사용되는 등가선형 주파수영역 해석 결과와 비선형 시간이력 유한요소해석 결과의 차이를 검토하였다. 그 비교결과는 등가선형강성을 사용하고 지반-구조물 상호작용을 고려하지 않는 주파수영역해석은 단주기영역의 구조물의 응답스펙트럼을 과대평가할 수 있음을 보여주었다. 응답스펙트럼에 대한 지반-구조물 상호작용의 영향은 기초크기와 구조물의 질량의 변화와 큰 관계 없이 일정하게 나타났다.

• BMB Reports
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• 제33권6호
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• pp.519-524
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• 2000

NF1 proteins are a family of DNA binding proteins which consist of two separate domains, N-terminal DNA binding domain and C-terminal transcription activation domain. The N-terminal 220 amino acids are highly conserved and are also known to mediate dimerization of NF1 proteins. The C-terminal regions of different type of NF1 proteins are heterogeneous and responsible for transcriptional activation. In this study, we tested the interaction between different domains of rat NF1-A protein by yeast two hybrid analysis and observed the interaction between C-terminal regions of NF1-A which do not contain the N-terminal dimerization domain. Our results showed that the C-terminal region of rat NF1-A between residues 231 and 509 strongly interacted not only with itself, but also with human NF1/CTF1 which is a different type of NF1. When the C-terminal region was divided into two fragments, one from residue 231 to 447 and the other from 448 to 509, the two fragments were able to interact with the C-terminal region of NF1-A significantly. This indicates that both fragments contain independent interaction domains. Analysis of the interactions with alanine substituted fragments showed that substitutions of the heptasequence, SPTSPTY of NF1-A, affected interaction between NF1 proteins. Our results strongly suggest that C-terminal regions may also be important for the formation of homo- and heterodimers in addition to the N-terminal dimerization domain. Also, the heptasequence motif may play some roles in dimer formation.