• ETRI Journal
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• 제33권5호
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• pp.814-817
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• 2011

In this letter, the distributions of direct current (DC) coefficients for P-frames in H.264/AVC are analyzed, and the distortion model of the Gaussian source under the quantization of the dead-zone plus-uniform threshold quantization with uniform reconstruction quantizer is derived. Experimental results show that the DC coefficients of P-frames are best approximated by the Laplacian distribution and the Gaussian distribution at small quantization step sizes and at large quantization step sizes, respectively.

• Advances in concrete construction
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• 제5권3호
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• pp.257-270
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• 2017

An experimental investigation was carried out to study the strength and behavior of reinforced cement concrete (RCC) frames with ferrocement and fiber reinforced concrete infill panel. Seven numbers of $1/4^{th}$ scaled down model of one bay-three storey frames were tested under reverse cyclic loading. Ferrocement infilled frames and fiber reinforced concrete infilled frames with varying volume fraction of reinforcement in infill panels viz; 0.20%, 0.30%, and 0.40% were tested and compared with the bare frame. The experimental results indicate that the strength, stiffness and energy dissipation capacity of infilled frames were considerably improved when compared with the bare frame. In the case of infilled frames with equal volume fraction of reinforcement in infill panels, the strength and stiffness of frames with fiber reinforced concrete infill panels were slightly higher than those with ferrocement infill panels. Increase in volume fraction of reinforcement in the infill panels exhibited only marginal improvement in the strength and behavior of the infilled frames.

• 한국안광학회지
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• 제20권1호
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• pp.9-14
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• 2015

목적: 본 논문에서는 안경테가 땀에 노출되었을 때 나타나는 변화를 알아보았다. 방법: 양백, 모넬 및 티타늄 재질의 안경테를 pH 6.5, 6.0, 5.0의 인공땀에 1주, 3주, 6주 동안 노출시킨 후 표면, 경도, 인장강도의 변화를 알아보았다. 결과: 인공땀에 의해 양백, 모넬, 티타늄 재질 안경테 표면의 부식이 유발되었으며 부식 양상은 각 재질별로 상이하였다. 인공땀의 pH와 노출시간에 비례하여 3가지 재질의 안경테 모두 경도가 감소하였으나 인장강도는 변화가 없었다. 결론: 인공땀에 의해 안경테의 표면 부식과 경도 변화가 관찰되었으므로 안경테의 일상적인 관리가 필요함을 제안한다.

• 한국지진공학회논문집
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• 제8권3호
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• pp.97-103
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• 2004

철골 중심가새골조의 경우 접합비용의 절감을 위해 가새가 설치된 스팬을 제외한 기둥들은 통상 중력기둥으로 설계된다. 따라서 중력기둥이 미치는 P-${\Delta}$ 효과를 내진성능 평가에 적절히 반영할 필요가 있다. 본 연구에서는 철골 중심가새골조의 중력기둥이 유발하는 P-${\Delta}$ 효과를 가상의 의지기둥(leaning column) 개념에 의해 간편하게 모델링할 수 있는 해석기법을 예시하였다. 역V형 가새골조를 사례로 하여 FEMA 273의 비선형정적해석법에 의한 내진성능평가를 수행하고 동적 P-Δ 증폭계수 적용에 있어서의 문제점을 지적하였다. 본 연구의 결과에 의할 때 P-${\Delta}$ 효과는 중심가새골조의 내진성능평가에 무시할 수 없는 영향이 있는 것으로 밝혀졌다. 아울러 기존연구에서 제시된 인장보강재에 의한 역V형 가새골조의 보강법은 내진성능향상에 매우 효과적임을 확인하였다.

• 국제초고층학회논문집
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• 제2권4호
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• pp.355-365
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• 2013

The paper reports results of recent studies on the effects of column support conditions on the lateral displacements of moment frames at incipient collapse. The article presents a number of exercises in the plastic theory of structures that lead to useful design formulae. It has been shown that Drift Shifting (DS) is caused due to differences in the stiffnesses of adjoining columns, and that changes in drift ratios are more pronounced at first level column joints in both fixed as well as pinned base frames. In well proportioned moment frames, DS in the upper levels could be minimized, even reduced to zero. It has been demonstrated that DS can be eliminated in properly designed fixed and grade beam supported (GBS) moment frames. Several examples, including symbolic P-delta effects, have been provided to demonstrate the validity and the applications of the proposed ideas to the design and drift control of moment frames. The proposed methodology is exact within the bounds of the theoretical assumptions and is well suited for preliminary design and teaching purposes.

• Korean Journal of Mathematics
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• 제7권2호
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• pp.235-244
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• 1999

We will derive some identities related to p-scalars, p-vectors, and non-holonomic frames in a generalized 2-dimensional Riemannian manifold $X_2$.

• 한국강구조학회 논문집
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• 제17권3호통권76호
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• pp.347-356
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• 2005

최근 들어 강구조 공장건축은 상당부분 P.E.B.시스템으로 지어지고 있으나 관련기술이 대부분 외국에서 수입된 것으로 전용프로그램(예, MBS, LTI 등)에만 의존하고 있고 국내의 설계지침이 없어서 AISC-ASD에 의해 설계하고 있다. 또한 P.E.B.골조의 구조적 거동을 검토한 연구 및 H형강을 이용한 요소기술 개발이 부족한 실정에 있다 특히, 기둥-보(rafter) 접합부는 Extended type end plate에 의한 접합에만 의존하여 과다설계의 경향이 있으므로. 접합부에 대한 구조적 검토가 필요하다. 따라서 이 연구에서는 P.E.B.시스템 공장건물에서 H형강-보(rafter)의 접합부(Extended/Flush type)의 구조성능을 실험적으로 평가하여 구조적, 경제적으로 우수한 P.E.B. 시스템 골조의 설계를 위한 기초자료를 제공하고자 한다.

• 한국지진공학회논문집
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• 제18권1호
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• pp.37-43
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• 2014

In current seismic design code, steel moment frames are classified into ordinary, intermediate, and special moment frames. In the case of special moment frames which have large R-factor, economic design is possible by reducing the design lateral force. However, there is difficulty for practical application due to constraints such as strong column-weak beam requirement. This study evaluated if steel intermediate moment frame could maintain enough seismic capacity when the R-factor is increased from 4.5 to 6. As for the analytical models, steel moment frames of 3 and 5 stories were categorized into four performance groups according to seismic design category. Seismic performances of the frames were evaluated through the procedure based on FEMA P695. FEMA P695 utilizes nonlinear static analysis(pushover analysis) and nonlinear dynamic analysis(incremental dynamic analysis, IDA). In order to reflect the characteristics of Korean steel moment frames on the analytical model, the beam-column connection was modeled as weak panel zone where the collapse of panel zone was indirectly considered by checking its ultimate rotational angle after an analysis is done. The analysis result showed that the performance criteria required by FEMA P695 was satisfied when R-factor increased in all the soil conditions except $S_E$.

• Steel and Composite Structures
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• 제6권6호
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• pp.513-529
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• 2006

This paper deals with the dynamic behaviour of cold-formed steel hollow frames with different connection stiffnesses. An analytical model of a semi-rigid frame was developed to study the influence of connection stiffnesses on the fundamental frequency and dynamic response of the frames. The flexibilities of the connections are modeled by rotational springs. Neglect of semi-rigidity leads to an artificial stiffening of frames resulting in shorter fundamental period, which in turn results in a significant error in the evaluation of dynamic loads. In the seismic design of structures, of all the principal modes, the fundamental mode of translational vibration is the most critical. Hence, experiments were conducted to study the influence of the connection stiffnesses on the fundamental mode of translational vibration of the steel hollow frames. From the experimental study it was found that the fundamental frequency of the frames lie in the semi-rigid region. From the theoretical investigation it was found that the flexibly connected frames subjected to lateral loads exhibit larger deflection as compared to rigidly connected frames.

• 대한수학회지
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• 제56권5호
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• pp.1285-1307
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• 2019

For a multiplication R-module M we consider the Zariski topology in the set Spec (M) of prime submodules of M. We investigate the relationship between the algebraic properties of the submodules of M and the topological properties of some subspaces of Spec (M). We also consider some topological aspects of certain frames. We prove that if R is a commutative ring and M is a multiplication R-module, then the lattice Semp (M/N) of semiprime submodules of M/N is a spatial frame for every submodule N of M. When M is a quasi projective module, we obtain that the interval ${\uparrow}(N)^{Semp}(M)=\{P{\in}Semp(M){\mid}N{\subseteq}P\}$ and the lattice Semp (M/N) are isomorphic as frames. Finally, we obtain results about quantales and the classical Krull dimension of M.