• Steel and Composite Structures
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• 제23권2호
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• pp.187-194
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• 2017

To reuse a broken plain concrete (PC) arch, a retrofitting method was proposed to ensure excellent structural performances, in which carbon fiber reinforced polymers (CFRPs) were applied to repair and strengthen the damaged PC arch through bonding and wrapping techniques. Experiments were carried out to reveal the deformation and the load carrying capacity of the retrofitted composite arch. Based on the experiments, repairing and strengthening effects of the CFRP retrofitted broken arch were revealed. Simplified analysing model was suggested to predict the peak load of the CFRP retrofitted broken arch. According to the research, it is confirmed that absolutely broken PC arch can be completely repaired and reinforced, and even behaves more excellent than the intact PC arch when bonded together and strengthened with CFRP sheets. Using CFRP bonding/wrapping technique a novel efficient composite PC arch structure can be constructed, the comparison between rebar reinforced concrete (RC) arch and composite PC arch reveals that CFRP reinforcements can replace the function of steel bars in concrete arch.

• 한국전산구조공학회논문집
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• 제17권2호
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• pp.131-140
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• 2004

철근콘크리트 구조물의 보수ㆍ보강 등의 유지관리를 위해서는 내구성과 내하성을 동시에 고려한 건전성평가의 의사결정기준이 절실히 요구된다. 본 논문은 CART-ANFIS을 사용하는 철근콘크리트 구조물에 대하여 효율적인 모델을 나타내었다. 철근콘크리트 구조물의 손상과 진단 등에 활용되어온 분류형 전문가시스템의 일종인 퍼지이론을 이용한 결정목 구조와 기존의 인공신경망을 이용한 결정목 구조의 건전성평가를 비교 분석한다. 손상된 철근콘크리트의 내구성 회복을 위한 보강설계 이론과 내하력 증가를 위한 보장설계 이론을 정립시켜 손상검출의 산정식을 유도하였다. 본 연구의 건전성 평가시스템 모델을 이용함으로서 보다 효율적인 철근콘크리트 유지관리 뿐만 아니라 생애주기비용 예측을 수행 할 수 있다.

• 한국환경과학회지
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• 제14권8호
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• pp.777-783
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• 2005

For the sustainable management of marine ecosystem in Masan Bay, we have to assess the carrying capacity and standard of target water quality. In this research, we assume that all pollutants loads are treated in Dukdong sewage treatment plant, then we simulate the physical-biological model for prediction water quality for the achievement of standard water quality. In 2001 year, for the achievement of COD 2.5 mg/L, we need to reduce COD $90\%$, nitrogen $30\%$, phosphate $90\%$ than that of the present value, According to these results, the water quality of sewage treatment plant is required to treat COD 13.5 mg/L, nitrogen 33.3 mg/L, phosphate 6,0 mg/L. If the sewage treatment plant will be expanded much larger in 2011, it will need to be treated in COD 6.6 mg/L, nitrogen 2.5 mg/L, phosphate 5 mg/L for the achievement of water quality standard in COD 2.5 mg/L.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권1호
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• pp.1-5
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• 1998

One cervical cancer cell line, C9, carrying human papillomavirus type 18 (HPV18) genes that is one of the major etiologic concoviruses for cervical cancer was characterized. This cell line was further characterized for its capacity related to the epithelial cell proliferation, stratification and differentiation in reconstituted artificial epithelial tissue. The in vitro construction of three dimensional artificial cervical opithelial tissue has been engineered using C9 epithelial cancer cells, human foreskin fibroblasts and a matrix made of type I collagen by organotypic culture of epithelial cells. The morphology of paraffin embedded artificial tissue was examined by histochemical staining. The artificial epithelial tissues were well developed having multilayer. However, the tissue morphology was similar to the cervical tissus having displasia induced by HPV infection. The characteristics of the artificial tissues were examined by determinining the expression of specific marker proteins. In the C9 derived artificial tissues, the expression of EGF receptor, as epithelial proliferation marker proteins for stratum basale was observed up to the stratum spinosum. Another epithelial proliferation marker for stratum spinosum, cytokerations 5/6/18, were observed well over the stratum spinosum. For the differentiation markers, the expression of involucrin and filaggrin were observed while the terminal differentiation marker, cytokeratins 10/13 was not detected at all. Therefore the reconstituted artificial epithelial tissues expressed the same types of differentiation marker proteins that are expressed in normal human cervical epithelial tissues but lacked the final differentiation capacity representing characteristics of C9 cell line as a cancer tissue devived cell line. Expression of HPV18 E6 oncoprotein was also observed in this artifical cervical opithelial tissue though the intensity of the staining was weak. Thus this artificial epithelial tissue could be used as a useful model system to examine the relationship between HPV-induced cervical oncogenesis and epithelial cell differentiation.

• 한국정밀공학회지
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• 제29권8호
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• pp.818-823
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• 2012

In order to predict necking behaviour of aluminium sheets, a crystal plasticity model is introduced in the finite element analysis of tensile test. Due to the computational limits of time and memory, only a small part of tensile specimen is subjected to the analysis. Grains having different orientations are subjected to numerical tensile tests and each grain is discretized by many elements. In order to predict the sudden drop of load carrying capacity after necking, a well-known Cockcroft-Latham damage model is introduced. The mismatch of grain orientation causes stress concentration at several points and damage is evolved at these points. This phenomenon is similar to void nucleation. In the same way, void growth and void coalescence behaviours are well predicted in the analysis. For the comparison of prediction capability of necking, same model is subjected to finite element analysis using uniform material properties of polycrystal with and without damage. As a result, it is shown that the crystal plasticity model can be used in prediction of necking and fracture behavior of materials accurately.

• 한국조경학회지
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• 제32권6호
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• pp.23-35
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• 2005

Korean goral (Nemorhaedus caudatus raddeanus) is an endangered species in Korea, and the rugged terrain of the Sorksan National Park $(373km^2)$ is a critical habitat for the species. Since the goral population is threatened by habitat fragmentation, it is essential to establish a reserve for the isolated goral population. The objective of this study was to propose a reserve for Korean goral in the national Park We employed habitat suitability model, habitat capability model, and the concept of minimum viable population. The results of the study were as follows. First, the carrying capacity and optimal density of gorals in the national park were projected to be 449 gorals, and 251 gorals, respectively Second, since only one patch was projected to satisfy the criteria of minimum viable population (50 individuals/during 50 years), the long term extinction possibility of gorals in the site would be very high. Finally, the patch that satisfy the minimum viable population of goral was proposed as the core zone of the goral reserve and adjacent patches were included as buffer zones.

• Computers and Concrete
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• 제26권1호
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• pp.95-106
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• 2020

Castellated beams fabricated from standard I-sections are being used for several structural applications such as commercial and industrial buildings, multistory buildings, warehouses and portal frames in view of numerous advantages. The advantages include enhanced moment of inertia, stiffness, flexural resistance, reduction in weight of structure, by passing the used plate girders, the passage of service through the web openings etc. In the present study, experimental and numerical investigations were carried out on concrete encased steel castellated beams with hexagonal openings under flexural loading. Various positions of openings such as along the neutral axis, above the neutral axis and below the neutral axis were considered for the study. From the experimental findings, it has been observed that the load-carrying capacity of the castellated beam with web opening above neutral axis is found to be higher compared to other configurations. Nonlinear finite element analysis was performed by using general purpose finite element software ABAQUS considering the material nonlinearities. Concrete damage plasticity model was employed to model the nonlinearity of concrete and elasto-plastic model for steel. It has been observed that FE model could able to capture the behaviour of concrete encased steel castellated beams and the predicted values are in good agreement with the corresponding experimental values.

• Structural Engineering and Mechanics
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• 제61권5호
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• pp.593-603
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• 2017

A high-efficiency simplified modelling approach is proposed for investigating the nonlinear responses of reinforced concrete linings of shield tunnels. Material and geometric nonlinearities are considered in the analysis of the lining structures undergoing large deformation before ultimately losing the load-carrying capacity. A beam-spring element model is developed to capture the force-transfer mechanism between lining segments and radial joints. The developed model is validated by comparing analyzed results to experimental results of a single-ring lining structure under two loading conditions: the ground overloading and the lateral unloading respectively. The results show that the lining structure under the lateral unloading due to excavation on the both sides of the tunnel is more vulnerable compared to the case of ground overloading on the top of the tunnel. A parameter study is conducted and results indicate that the lateral pressure coefficient has the greatest influence on the behaviour of the lining structure.

• Korean Journal of Hydrosciences
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• 제8권
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• pp.31-40
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• 1997

Flow carrying capacity of water distribution systems is getting reduced by deterioration of pipes in the systems. The objective of this paper is to present a managerial decision-making model for the rehabilitation of water distribution systems with a mininum cost. The decisions made by the model also satisfy the requirements for discharge and pressure at demanding nodes in the systems. Replacement cost, pipe break repair cost, and pumping cost are considered in the economic evaluation of the decision along with the break rate and the interest rate to determine the optimal replacement time for each pipe. Then, the hydraulic integrity of the water distribution system is checked for the decision by a pipe network simulator, KYPIPE, if discharge and pressure requirements are satisfied. In case the system does not satisfy the hydraulic requirements, the decision made for the optimal replacement time is revised until the requirments are satisfied. The model is well applied to an existing water distribution system, the Seoul Metropolitan Water Supply System (1st Phase). The results show that the decisions for the replacement time determined by the economic analysis are accepted as optimal and hydraulic integrity of the system is in good condition.

• 디지털융복합연구
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• 제14권10호
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• pp.195-203
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• 2016

본 논문은 정보화전략계획 수립에서의 환경 분석 단계를 빠르게 수행하여, 결과물에 대한 품질을 향상시킬 수 있는 기반을 마련할 수 있는 방법을 제안한다. 기존의 환경 분석 방법은 외부 환경 분석, 내부 역량 분석, 정보화 방향 도출 활동으로 구성되어 있다. 환경 분석 첫 번째 단계에 현황파악, 주요 프로젝트 이해관계자와 인터뷰 준비, 인터뷰 수행을 통하여 초기 정보화 방향을 획득하기 위한 활동들을 추가하였다. 그리고 외부 환경 분석, 내부 역량 분석을 위한 핵심 질문 중심의 융복합 시나리오 기반 분석 모형을 적용하였다. 분석모형으로 외부 환경 분석, 내부 역량 분석 활동을 수행하여, 도출된 정보화 방향을 초기에 설정한 정보화 방향과 검증할 수 있도록 하였다. 연구 결과는 실제 프로젝트 현장에 적용하여, 빠르게 프로젝트를 수행할 수 있었고, 프로젝트 결과물에 대한 품질을 향상시킬 수 있었다.