• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.8-14
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• 2011

Japanese larch glulam was used as structural members to develop a modern engineered wood jointing system using traditional post and beam structure. For the connections comprised of traditional joining and drift-pins, structural members are processed at a pre-cut factory. As a basic study to examine and increase the whole shear performance of portal frame, pin withdrawal test and moment resistance tests were conducted on each connection. The post and beam members with specified connectors showed good bearing performance in the wood members' joining system, column-base and beam-end. Moment rigidity was a bit better in a joint with higher slenderness ratio of drift-pin, but moment resistance performances, yield moment and maximum moment, were excellent in smaller one.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.2
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• pp.13-24
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• 1988

A geometrically nonlinear analysis procedure for plane frame structures in order to study the static and dynamic post-buckling behavior of these structures subjected to circulatory forces is presented. The elastic and geometric stiffness matrices, the mass matrix and load correction stiffness matrix are derived from the extended virtual work principle, where the tangent stiffness matrix becomes non-symmetric due to the effects of non-conservative circulatory forces. The dynamic analysis of plane frame structures subjected to circulatory forces in pre- and post-buckling ranges is carried out by integrating the equations of motion directly by the numerically stable Newmark method. Numerical results are presented in order to demonstrate the vality and accuracy of the proposed procedure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.3
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• pp.57-64
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• 1989

This study presents a reliability-based optimum design of reinforced concrete frames, in which the AFOSM and SOSM methods are applied for the evaluation of the failure probabilities, and the sequential linear programming method is used as a practical approach to the system optimization. One-story two-bay reinforced concrete frame is chosen for the numerical illustration of the proposed reliability-based optimum design. As a result, it is found that the proposed procedure for the reliability-based optimization of RC frames could provide the accurate estimation of the optimal level of safety, and appears applicable to real structures with reasonable complexity. It is shown in the paper that the probability distributions of the basic random variables and the uncertainties of the applied loadings and material strengths may have great effect on the optimum design, but the AFOSM and SOSM methods do not show significant discrepancy in the optimum design results, but the former appears more realistic and time saving than the latter for this specific study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.91-105
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• 1992

For the analysis of multistory frames with sidesway, no adequate procedures can be found in the classical methods of structural analysis. Even well-known procedures such as the slope-deflection method and the moment distribution method may not be effective tools since those methods require a multiple of computational labor and/or yield results of approximate values. In this study, a direct method is developed and proposed for the analysis of multistory frames with sidesway, which is due to the lateral loads, asymmetry of the structure itself, or asymmetry of vertical loadings. The proposed method is to obtain simple forms of equations derived by a mathematical formulation of the moment distribution procedure combined with successive correction concept. Numerical illustrations show that the results obtained by the proposed method agree well with those by rigorous ones. Undoubtedly, this newly developed method can be applied more easily for the analysis of structural frames without joint translation as well as continuous beams.

• Journal of Korean Society of Steel Construction
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• v.15 no.3
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• pp.299-311
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• 2003

This paper presents a finite element procedure to estimate the ultimate strength of space frames considering spread of plasticity. The improved displacement field is introduced based on the inclusion of second-order terms of finite rotations. All the non-linear terms due to bending moment, torsional moment, and axial force are precisely considered. The concept of plastic hinges is introduced and the incremental load/displacement method is applied for elasto-plastic analyses. The initial yield surface is defined based on the residual stress, and the full plastification surface is considered under the combined action of axial forces, bending and torsional moments. The elasto-plastic stiffness matrices are derived using the flow rule and the normality condition of the limit function. Finite element solutions for the ultimate strength of space frames are compared with available solutions and experimental results.

• Journal of Broadcast Engineering
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• v.19 no.1
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• pp.83-95
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• 2014

Hand posture recognition is an important technique to enable a natural and familiar interface in HCI(human computer interaction) field. In this paper, we introduce a hand posture recognition method by using a depth camera. Moreover, the hand posture recognition method is incorporated with MPEG-U based advanced user interaction (AUI) interface system, which can provide a natural interface with a variety of devices. The proposed method initially detects positions and lengths of all fingers opened and then it recognizes hand posture from pose of one or two hands and the number of fingers folded when user takes a gesture representing a pattern of AUI data format specified in the MPEG-U part 2. The AUI interface system represents user's hand posture as compliant MPEG-U schema structure. Experimental results show performance of the hand posture recognition and it is verified that the AUI interface system is compatible with the MPEG-U standard.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.661-672
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• 2003

The advanced analysis and optimal design of semi-rigid frame were presented. Advanced analysis can predict the combined nonlinear effects of connection, geometry, and material on the behavior and strength of semi-rigid frames. The Kishi-Chen power model was used to describe the nonlinear behavior of semi-rigid connections. Geometric nonlinearity was determined using stability functions. On the other hand, material nonlinearity was determined using the Column Research Council (CRC) tangent modulus and parabolic function. The direct search method proposed by Choi and Kim was used as optimization technique. The member with the largest unit value evaluated using the LRFD interaction equation was replaced one by one with an adjacent larger member selected from the database. The objective function was assumed as the weight of steel frame, with the constraint functions accounting for load-carrying capacities, deflections. inter-story drifts, and ductility requirement. Member sizes determined by the proposed method were compared with those derived using the conventional LRFD method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.705-708
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• 2020

공공시설에 대한 안전점검은 공공시설의 노후화에 따라 정기적인 검사의 필요성이 요구되고 있다. 기존의 안전점검 방식은 대부분 육안으로 점검하는 것에 의존하는데 이는 점검자의 숙련도에 따라 결과의 품질이 달라지게 된다. 본 논문에서는 XAI 기반의 공공시설물 건전도 안전검사 평가시스템을 제안하며, 이는 점검자의 숙련도와 무관하게 항상 같은 결과를 도출해 내며 XAI 를 통해 사용자에게 안전점검에 대한 결과를 제시해준다. 공공시설물 중 터널 시설물의 안전검사 평가시스템을 기반으로 하는 연구를 진행하였으며 이는 수정없이 교량 시설물 등 다른 공공시설물에 적용이 가능하다. 본 논문은 5 가지로 구분된다. 1) 터널 이미지와 균열에 마스크를 적용한 이미지 두 가지의 데이터 셋을 448x448 로 생성한다. 2) UNet 과 Resnet152 의 두 모델을 적용한 혼합 모델을 이용하여 생성한 데이터 셋을 훈련시킨다. 3) 훈련된 혼합 모델에서 생성된 분할 이미지에 대해 노이즈 제거 과정을 진행한다. 4) 노이즈 제거가 끝난 이미지에 스켈레톤화(Skeletonization)를 적용시켜 균열 이미지의 뼈대를 구한다. 뼈대 이미지 기반으로 균열의 길이, 두께, 위치등의 정보를 얻는다. 5) XAI 부분에서는 뼈대 이미지의 정보를 토대로 균열의 위치, 두께, 길이 등에 대해 계산을 진행한 후 사용자에게 제시해준다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.123-133
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• 2006

The main objective of this study is to develop an optimization algorithm of framed structures with rigid and various semi-rigid connections using the multilevel dynamic programming and the sequential unconstrained minimization techniques (SUMT). The second-order elastic analysis is performed for steel framed structures. The second order elastic analysis is developed based on nonlinear beam-column theory considering the bowing effect. The following semi-rigid connections are considered; double web angle, top-seat angle and top-seat angle with web angle. We considered the three connection models, such as modified exponential, polynomial and three parameter model. The total weight of the structural steel is used as the objective function in the optimization process. The dimensions of steel cross section are selected as the design variables. The design constraints consist of strength requirements for axial, shear and flexural resistance and serviceability requirements.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.4
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• pp.265-273
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• 2001

The sea urchin has been used as sea food in many countries. This species has also been an important organism of embryological studies for more than a century. In recent years, sea urchin embryos are being used as testing materials for toxicity of pollutants and toxins. Usefulness of sea urchin embryos as experimental models comes from the easiness in obtaining sea urchin samples and a lot of gametes, in rearing embryos in the laboratory, in observing the cellular movement and organ formation during the embryogenesis and in manipulating blastomeres and genetic maferials. The sea urchin in itself is a key organism for the understanding of deuterostome evolution from the protostomes and of indirect development of marine invertebrates which undergo the planktotrophic larval stage. A fertilized sea urchin egg goes through rapid cleavage and becomes a 60 cell embryo 7hr after fertilization. It then develops into a morula, a blastula, a gastrula and finally a pluteus larva approximately 70 hr after fertilization. At the 60 cell stage, the embryo comprises of five territories that express territory-speciflc genes and later form different organs. Micromeres at the vegetal pole ingress into the blastoceol and become the primary mesenchyme cells(PMCs). PMCs express genes involved in skeletogenesis such as SM30, SM37, SM50, PM27, msp130. Among the genes, SM37 and SM50 are considered to be members of a gene family which is characterized by early blastula expression, Glycine-Proline-Glutamine rich repeat structures and spicule matrix forming basic proteins. Genetic studies on the sea urchin embryos help understand the molecular basis of indirect development of marine invertebrates and also of the biomineralization common to the animal kingdom.