• 한국전산구조공학회논문집
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• 제12권3호
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• pp.385-396
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• 1999

최근 공학분야에서 다루어지고 있는 문제의 규모가 대형화하고 있으며 이러한 대형구조물의 구조설계는 부재의 강도설계 및 절점의 변위조절을 위하여 많은 수의 구조해석을 요구한다. 한 대의 개인용 컴퓨터에 의한 대형구조물의 구조해석은 대용량의 기억장치와 많은 계산 시간이 요구되므로 반복적 해석이 필요한 대형구조물의 설계에 효율적으로 이용되기 어려운 실정이다. 따라서, 본 논문에서는 이러한 문제에 대한 대안으로 다수의 개인용 컴퓨터들을 네트워크로 연결하여 고성능 병렬연산시스템을 구성하고 이에 적합한 두 가지 형태의 분산구조방정식해법들을 반복법인 PCG 알고리즘을 이용하여 개발하였다. 대형구조물을 위한 분산구조해석법은 구조해석 과정에 요구되는 각 컴퓨터 상호 간의 통신회수와 통신량을 최소화할 수 있도록 개발되었다. 분산구조해석법의 성능은 대규모 3차원 트러스 구조물 및 144층 가새 튜브구조물의 구조해석에 적용하여 분석하였다.

• 한국기계가공학회지
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• 제15권1호
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• pp.122-128
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• 2016

The purpose of this study was to develop improved strength of an arm and a boom on over-load environment, which causes damage in the initial design statement. To develop improved strength of an excavator front group, we calculated load conditions using the MATLAB program, and using these conditions, we performed a structural analysis of an excavator front group for the maximum digging force condition. Finally we performed a topology optimization to reduce weights of an arm and a boom, and we re-modeled an arm and a boom based on the topology design results and re-performed the structural analysis. The strength of the re-design is higher than the initial design but its weight is almost the same as the initial design.

• 한국대기환경학회지
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• 제33권4호
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• pp.297-305
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• 2017

In this study, the activity and structural properties of catalysts prepared by mechanochemical method under dry condition were studied. A dry milling was used as a mechanochemical method. The precursors of vanadium were $NH_4VO_3$ and $V_2O_5$. The activity and characterization of the catalysts prepared by dry milling were compared with those prepared by impregnation. In addition, the correlation between the catalytic activity and the structural characteristics was observed through XRD, Raman, and $H_2$-TPR analysis. As a result, the monomeric vanadate species exhibited excellent redox characteristics, which were confirmed to be related to the catalytic activity.

• Structural Engineering and Mechanics
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• 제59권4호
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• pp.739-759
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• 2016

The failure of civil engineering systems is a consequence of decision making under uncertain conditions. Generally, buried flexible pipes are designed for their transversal behavior to prevent from the important failure mode of buckling. However, the interaction effects between soil and pipe are neglected and the uncertainties in their properties are usually not considered in pipe design. In this regard, the present research paper evaluates the effects of these uncertainties on the uncertainty of the critical buckling hoop force of flexible pipes shallowly buried using the subgrade reaction theory (Winkler model) and First-Order Second-Moment (FOSM) method. The results show that the structural uncertainties of the studied pipes and those of the soil properties have a significant effect on the uncertainty of the critical buckling hoop force, and therefore taking into account these latter in the design of the shallowly flexible pipes for their buckling behavior is required.

• 한국환경복원기술학회지
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• 제8권1호
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• pp.52-62
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• 2005

The objectives of this research is searching for the improvement scheme of spacial use of the Nature Environmental Conservation and its Utilization Facility through the analysis of those existing facilities from the structural and operational view points. In this study, firstly, analysis is commencing with the distinction of lawful and operational concepts of Nature Environmental Conservation and its Utilization Facility. In law, the concept is defined as an individual facility, while practical use of the concept has been understood as a collective space itself. Secondly, frequency tables in regard to the duration of the construction, types of location and objectives, and facility numbers are prepared on the basis of 53 cases of completed and under construction facilities. Conclusively, through the comparisons of facilities of Korea, United Kingdom and Germany, the future considerations on the improvement of the facilities in light of structural and operational aspects has been recommended. In structural view, ecological conservation aspect should be considered from the planning stage of the facility. And at the operational stage, various considerations should be given to the employment of facility experts and development of educational programs respectively.

• 대한간호학회지
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• 제43권3호
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• pp.399-408
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• 2013

Purpose: The study was done to construct and test a structural model to explain primipara breastfeeding behavior. Methods: The participants were 213 primiparas on postpartum wards. Data were analyzed using the PASW 18.0 and AMOS 19.0 programs. Results: Fitness statistics for the hypothetical model were appropriate ($x^2$=38.50, p=.070, GFI=.96, RMSEA=.05, AGFI=.93, NFI=.95, TLI=.97, CFI=.98, PNFI=.57, $x^2/df$=1.43). Breastfeeding behaviors were directly influenced by intention to breastfeed, perceived effectiveness of breastfeeding, and the amount of supplementary feeding. The amount of supplementary feeding had the largest direct impact on breastfeeding behavior. The largest total effect on breastfeeding behavior was intention to breastfeed. The environment of the maternity hospital indirectly influenced breastfeeding behavior. These factors explained 18.9% of variance in the primipara breastfeeding behavior. Conclusion: The results of the study indicate that in order to promote primipara breastfeeding the amount of supplementary feeding immediately after the birth should be limited and an environment that encourages exclusive breastfeeding in the hospital should be provided. The results also suggest it is necessary to provide nursing interventions that increase the intention to breastfeed and the perceived effectiveness of breastfeeding.

• 디지털융복합연구
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• 제7권4호
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• pp.127-140
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• 2009

This dissertation aims to empirically analyze the factors that determine the market competitiveness that would enable SaaS enterprises to survive. The contents of this dissertation includes; (l)analysis of factors that determine market competitiveness of domestic SaaS enterprises, (2)structural analysis of factors that determine the market competitiveness of SaaS enterprises on the their performance. Results of analysis of this dissertation are as follows. First, the factors that determine market competitiveness of SaaS enterprises were found to include (l)enterprise management competence, (2)competence for technological possession, (3)reliability and safety, (4)customer management competence, and (S)competence to cope with external environment of the enterprise. Second, the outcome of structural analysis of factors that determine the market competitiveness of SaaS enterprises on the their performance illustrated that (l)enterprise management competence and (2)competence for technological possession has structural relationship of imparting influence on the (6)enterprise performance by the full medium of (3)reliability and safety, (4)customer management competence, and (5)competence to cope with external environment of enterprise.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.993-996
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• 2008

현재 건설현장에서 구조체 콘크리트 강도는 구조체에서 채취한 코어공시체 강도가 가장 신뢰성이 높다고 알려져 있다. 그러나 코어 채취시 구조체의 손상이나 배근의 절단에 의해서 구조체 성능의 지장을 줄 우려가 있고 공시체 채취후의 보수 등에 몇 가지 문제가 있다. 또한 비파괴 검사에 의한 경우 결과값을 추정하는 방법이기 때문에 신뢰도가 매우 저하되는 단점을 가지고 있다. 본 연구 개발의 목표는 접합 분리 시험체 및 콘크리트의 코어채취에 의한 직접적인 강도 측정방법과 계절별 관리용 공시체 강도를 비교분석하여 보다 발전된 구조체 콘크리트의 성능 평가방법을 제시하여 합리적이고 실용적인 구조체 콘크리트의 시공 품질관리 기법을 제안 하는데 목적이 있다.

• 한국표면공학회지
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• 제49권1호
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• pp.32-39
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• 2016

In this study, Al and Zn arc thermal spray coatings were carried out onto the substrate of SS400 steel to improve corrosion resistance and durability of hull structural steel for ship in marine environment. Therefore cavitation-erosion test was conducted to evaluate the durability of painted and thermal spray coated specimens. And then the damaged surface morphology and weight loss were obtained to compare with each other, respectively. As a result, the painted specimen was the poorest cavitation resistance characteristics because surface damage behavior appeared to be exfoliated in bulk shape during the cavitation experiment. And Zn thermal spray coating layer presented the significant surface damage depth due to relatively low surface hardness and local cavitation damage tendency. On the other hand, as a result of the weight loss analysis, the painting layer presented the poorest cavitation resistance and the Al thermal spray coating layer relatively showed the best results after cavitation experiment.

• Structural Engineering and Mechanics
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• 제88권4호
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• pp.323-334
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• 2023

The submerged floating tunnel (SFT) infrastructure has been regarded as an emerging technology that efficiently and safely connects land and islands. The SFT route problem is an essential part of the SFT planning and design phase, with significant impacts on the surrounding environment. This study aims to develop an optimization model considering transportation and structure factors. The SFT routing problem was optimized based on two objective functions, i.e., minimizing total travel time and cumulative strains, using NSGA-II. The proposed model was applied to the section from Mokpo to Jeju Island using road network and wave observation data. As a result of the proposed model, a Pareto optimum curve was obtained, showing a negative correlation between the total travel time and cumulative strain. Based on the inflection points on the Pareto optimum curve, four optimal SFT routes were selected and compared to identify the pros and cons. The travel time savings of the four selected alternatives were estimated to range from 9.9% to 10.5% compared to the non-implemented scenario. In terms of demand, there was a substantial shift in the number of travel and freight trips from airways to railways and roadways. Cumulative strain, calculated based on SFT distance, support structure, and wave energy, was found to be low when the route passed through small islands. The proposed model helps decision-making in the planning and design phases of SFT projects, ultimately contributing to the progress of a safe, efficient, and sustainable SFT infrastructure.