This paper aims to reveal the effects of the K- turbulence model on the performance analysis of battery cooling system for electric vehicle. The maximum temperature, the difference of temperature, and temperature distributions on the battery module were compared with and without K- turbulence model under the different flow rate. It can be expected that the maximum temperature of K- turbulence model is corrected by using the average error rate without the result of K- turbulence model.
This work studies the variability of flatfish sales revenue. The theoretical analysis draws functions for equilibrium price and quantity using expectation hypotheses. The functions include unpredictable phenomenon with dummy variable and GARCH. The equilibrium function, using adaptive expectation hypothesis, contains the independent variables of supply and demand, while the equilibrium function, embodying rational expectation hypothesis, includes only the independent variables of supply side, because the demand side disappears by the information extraction process theoretically, if economic subjects build the expectation rational.
The empirical analysis shows: the variability of flatfish production has a spillover effect on the variability of revenue with the adaptive expectation hypothesis. In the case when the model has a rational expectation hypothesis, the variability of flatfish production has a spillover effect on the revenue (the mean equation of GARCH model). This study indicates that there is the variability in flatfish production and sales revenue, and the spillover effect between them. The result can help to build of the rational system for the fishery income stability.
As the industrial society develops, the management of the production line becomes more and more important. There are also diversifying Management methods by industry. In addition, National Competency Standards (NCS) have also been developed. As a result, It has been created standards for each job and provide education and training standards for industrial production management tasks. Customer satisfaction is an ever-growing concern of management throughout the world. In addition, Colleges are focusing on vocational education. Because of the opening of the education market, They are competing in various ways. And, To survive in this competition. They are making great efforts to improve the lecture satisfaction. If education is regarded as an industry, it can be classified as a representative service industry. Because it is formed as a perfect competition between colleges. And then in this paper, This will focus on the mechanical production Manager duties of industrial engineering department related NCS. This study also conducted empirical studies to analyze factors affecting the curriculum using the KANO analysis.
The purpose of this study is to make a generalized analytical based on the proposed experiments on reinforced concrete(RC) partially infilled frames by U-type precast concrete(PC) wall panels with openings. RC frame and PC wall panels were connected with different strengths. Therefore, we developed modified strut-tie model(STM) with two seismic retrofitting specimens and conducted a nonlinear analysis by using a computer analysis program. Based on the test results, truss member of modified STM was designed, applying the strut-tie model theory of ACI 318M-11 Appendix- A. As a result, the modified STM analysis results were very similar to the experimental results. As a result of the load-displacement curve comparison, the failure load were similar within 5∼17% of error range. In particular, the experimental results and the results of modified STM analysis show that the failure behavior almost matched.
Cyclic loading test was performed on the partially infilled reinforced concrete(RC) frames by L-type precast concrete(PC) wall panels with the connections of two different strength. Based on the results of experimental test, the nonlinear analysis was practiced with modified strut-tie model(STM) method by using a computer program. Truss member of modified STM was designed, applying the strut-tie model theory of ACI 318M-11 Appendix-A. Modified STM was designed with two ways according to the test result. PC wall panel and RC frame were assumed to composite when push loading applied. The PC and RC structures were also assumed to behave non-composite and those two structures connected with link(top connector) when pull loading applied. The connection was designed by using elastic link of program. The results of analytical modified STM process generally conform to the experimental results. The failure load and the failure mode of the specimens could be predicted using modified STM. The ratio of failure load measured in specimens to analytical values were between 0.83∼1.16. The member or connection which was failed in experiment yield in the results of modified STM. The failure mode perfectly matched.
Modified dapped end, precast prestressed double-tee slabs were considered in this research. It can facilitate insertion of service ducts at the dapped ends. The total depth of the floor slab may be reduced. In addition, the underside of the double-tee slab showed simpler appearance. Static three-point shear loading test was performed on full-scale specimens. And three modified single-tee slabs were analyzed by strut-tie model method. The specimen failed during the test in the same location as predicted by the strut-tie analytical model. The analysis of experimental results in comparison to the analysis results revealed that the experimental failure loads manifested 108% of analytical failure loads on the average.
Fuel consumption in fisheries is a primary concern due to environmental effects and costs to fishermen. Much research has been carried out to reduce the fuel consumption related to fishing operations. The fuel consumption of fishing gear in fishing operation is generally related to hydrodynamic resistance on the gear. This research is to propose a low drag generated midwater trawl in terms of the gear design improvement using simulations. The results from the simulation were verified with results that mirrored the model experiments. From the results, the resistance force of the proposed gear decreased to 29% compared to that of the current gear. Furthermore, the gear performance also improved with increased gear mouth compared to the current one. Therefore, the proposed gear will be helpful to reduce the greenhouse gases from fishing operation. It will also contribute to the fishing industry by saving fuel.
오탁방지막이 바닷물 속에 설치되어 있을 때 조류와 파도가 변할 때 움직임과 앵커 파주력을 초과하는 유체력이 작용할 경우의 이동 메카니즘을 질량-스프링법으로 해석하였다. 설치 위치는 전남 진도군 임회면 굴포리 동령개 포구 해역이다. 앵커의 파주력을 초과하는 장력은 0.05 m/s에서는 318초 후에 도달하였고, 0.15 m/s에서는 77초, 0.25 m/s에서는 43초, 0.3 m/s에서는 37초 후에 앵커가 움직이기 시작하여, 조류 속도가 0.01 m/s로 증가함에 따라서 평균 11.2 초 정도, 앵커 이동시작 시간이 단축되고 있었다. 조류만 작용할 때와 파랑이 추가될 때의 차이점은 유속이 느릴 경우, 앵커의 이동이 시작되는 시간의 차이가 7.6 % 정도 발생하였으나, 유속이 빠른 경우는 4.3 %미만으로 큰 차이가 없이 앵커 이동이 시작되는 것을 알 수 있었다. 조류 속도가 0.13 m/s를 초과하고 파도의 방향이 일치하면 주변의 해저 구조물과의 충돌로 인해 오탁방지막 성능이 정상적으로 작동하지 않을 수 있으니, 오탁방지막을 바다에 설치할 때 해수의 흐름 상황 등을 질량-스프링 방법으로 면밀하게 검토해야 한다.
This study concerned the analysis on the efficiency of the conversion of water tank type supply system to direct water supply system to examine the feasibility of the conversion, as well as the calculation of optimal conversion range that enables the supply of safe, high-quality water at stable pressure in accordance with the standards of water supply facility. The results of this research showed that when converting water supply system from water tank type supply system to direct water supply system, more nodal points could be properly converted and more reduction of electricity usage was expected in case water pressure rather than residence time was fixed. This means that higher efficacy can be obtained by fixing water pressure when converting water supply system. However, since the number of the locations that received on-spot inspection was small and the electricity usage measured was not exclusively by water supply facility, it is difficult to judge that such reduction of electricity usage accurately represents reduced electricity usage by water supply facility alone. therefore, after having secured on-spot information about a larger number of locations in apartment complexes that have converted water supply system, and utilizing information about electricity usage exclusively by water supply facility, the proposed method of this research could be applied to accurately deducing expected reduction of electricity usage by water supply facilities of various other apartment complexes. It is also considered possible to deduce an effective operation method of water supply system by finding out an area that shows low pressure or low residual chlorine concentration in the optimal conversion range of water supply, followed by estimating the proper location of pumping station or the proper chlorine dosage at the power purification plant that supply water to the target area.
이 연구에서는 지표 관측 자료와 위성 자료 그리고 GWNU 단층 복사 모델을 이용하여 맑은 상태의 전천 일사 량을 계산하였으며, 전운량에 따라 관측 및 모델의 일사량 값을 비교 분석하였다. 연구 자료는 2012년 강릉원주대학교 복사 관측소의 전천 일사량, 기온, 기압, 습도, 에어로졸 등의 관측 자료와 OMI 센서의 오존전량 자료 그리고 구름의 유무 및 전운량을 판단하기 위하여 자동 전운량 장비인 Skyview 자료를 이용하였다. 전운량이 0 할인 맑은 날의 경우 관측 값과 모델 값이 0.98로 높은 상관계수를 나타내었으나 RMSE가 36.62Wm−2로 비교적 높게 나타났다. 이는 Skyview 장비가 얇은 구름이나 박무 및 연무 등의 기상상태를 판단하지 못하였기 때문이다. 흐린 날의 경우 구름의 영 향을 보정하기 위해 전운량과 두 값의 차에 대한 비율을 이용한 회귀식을 복사 모델에 적용하였으며, 장비의 오탐지를 제외한 경우 상관계수가 0.92로 높은 상관성을 보였으나 RMSE가 99.50 Wm−2으로 높은 값을 보였다. 더 정확한 분석 을 위해서는 직달 성분의 차폐 유무 및 구름 광학 두께를 포함한 다양한 구름 요소의 추가적인 분석이 요구된다. 이 연구결과는 분 또는 시간에 따른 일사량을 산출하여 일사량이 관측되지 않는 지역에서 유용하게 사용될 수 있다.
This paper aims to reveal the effects of the K-ε turbulence model on the performance analysis of battery cooling system for electric vehicle. The maximum temperature, the difference of temperature, and temperature distributions on the battery module were compared with and without K- ε turbulence model under the different flow rate. It was found that there was no need to apply K-ε turbulence model when the flow rate is over 500m3/h because the difference of maximum temperature is under the 6℃.
Many studies are conducted in several fields for fragility analysis of structures or elements which is a probabilistic seismic safety analysis in consideration with uncertainty of seismic loading. It is hard to directly conduct fragility analysis for an infrastructure with social importance due to its size. Therefore, a fragility analysis for an infrastructure mainly conducted in element level or conducted with scaled model built in accordance with similarity law. In this article, fragility analysis for prototype and scaled model of reinforced concrete column was conducted with numerical models which had been updated by the results of shaking table test and pseudo dynamic test. As a result, response stress from the numerical analysis result of prototype model was higher than that from scaled model due to different stiffness ratios between steel and concrete. However, the probability of failure for scaled model was higher than that for prototype model because failure criteria for scaled model was down due to similarity law. Also it was evaluated that probability of failure by using log normal standard deviation of response stresses by spectrum matched accelerograms was more reliable than probability of failure by using existing coefficient of variation normally used.
UPS system in the liquefied natural gas(LNG) receiving terminal is one of the fundamental equipment that need to sustain operation during earthquake. In this study, modal identification test of UPS system was performed based on IEEE Std. 693-2005 and natural frequencies and modal damping, mode shapes had been identified. In addition, tri-axial time history test was performed to check the behavior and stress of the equipment during earthquake. Eigenvalue analysis was performed and analysis model was modified by reflecting the results of the test. Static analysis by dead weight and response spectrum analysis were performed to compare the combined stresses with the stress results of test. Dynamic characteristics and combined stresses under seismic load condition of the improved analysis model were similar to the test results and in this regard the compatibility was proved.
최근 전 세계적으로 오픈소스 소프트웨어에 대한 관심이 증가함에 따라 다양한 분야에 오픈소스 소프트웨어가 도입되고 있으며 그 활용도 증가하고 있는 추세이다. 이러한 현상은 공간정보 분야에도 유사하여, 전 세계적으로 오픈소스 공간정보 소프트웨어에 대한 관심이 증가하고 있고, 국내에서도 최근 들어 관심이 급증하고 있는 실정이다. 그러나 국내 공간정보산업 사업체 중에서 오픈소스 소프트웨어 관련 기업의 수는 매우 적을 뿐만 아니라 오픈소스를 통한 비즈니스 모델의 발달도 미약한 수준이다. 본 연구에서는 오픈소스 소프트웨어 비즈니스 모델 선행연구 분석을 통해 오픈소스 공간정보 소프트웨어와 관련하여 어떠한 비즈니스 모델이 가능한지를 살펴보고, 국내 오픈소스 공간정보 소프트웨어 관련 기업의 오픈소스 활용현황과 비즈니스를 분석한 후 기업의 유형별로 어떠한 오픈소스 소프트웨어 비즈니스 모델이 가능한 지를 전략적으로 제시함으로써 오픈소스 공간정보 소프트웨어 관련 기업의 활성화를 도모하고, 나아가 국내 오픈소스 공간정보 소프트웨어 생태계를 활성화하는 기반을 마련하고자 한다.
Abstract: In this study, finite element analysis modeling is proposed to evaluate middle- and low-rise steel-frame buildings constructed in South Korea. Two steel-frame joint specimens with welding joint parts were constructed and evaluated. Two types of displacement load, monotonic and cyclic, were used to evaluate the steel-frame joint specimens. According to the experimental results, the maximum moment of the cyclic test results was 80% smaller than that of the monotonic test results. Local buckling was observed in the compression area of the H-beam flange. A finite element analysis model based on the experimental results was proposed to analyze the steel-frame joint specimens. The numerical results predicted the experimental behavior of the steel-frame joint specimens well. Therefore, it is possible to use the proposed finite element analysis model to evaluate middle- and low-rise steel-frame buildings constructed in South Korea.
Fish mortality is the most important success factor in aquaculture management. To analyze the effect of mortality considering biological and economic condition is a important problem in land-based aquaculture. This study is aimed to analyze the effect of mortality for duration of cultivation in land-based aquaculture. This study builds the mathematical model that finds the value of decision variable to minimize cost that sums up the water pool usage cost, sorting cost, fingerling cost and feeding cost under critical standing corp constraint. The proposed mathematical model involves many aspects, both biological and economical: (1) number of fingerlings (2) timing and number of batch splitting event, based on (3) fish growth rate, (4) mortality, and (5) several farming expense. Numerical simulation model presented here in. The objective of numerical simulation is to provide for decision makers to analyse and comprehend the proposed model. When extensive biological and cost data become available, the proposed model can be widely applied to yield more accurate results.
현재 항로표지시설에 대한 객관적 지표 및 평가기준에 따른 적정성 및 효용성 등 사후평가는 설치 이후 항만 운영 중 변경될 수 있는 위험요소 및 환경 변화를 고려하여 이루어지지 않고 있는 실정이다. 항로표지시설에 대한 객관적 지표를 설계하여 모든 항로표지시설에 공통된 평가기준 및 분석모델을 적용하여 환경 및 항만 여건 변화에 따른 적정성 및 효용성을 분석할 필요성을 인식하고, 이 연구에서는 우선적으로 항로표지시설 중 전국 37기가 운영 중인 유인등대를 중심으로 20개의 기능평가 지표를 설계하고 적용하였다. 객관적 평가지표에 따라 기능평가 후 계층분석과정(AHP, Analytic Hierarchy Process) 기법을 통해 항만 운영의 특성, 국가정책, 전문가 의견 등을 반영하였으며, 항로표지시설의 특수성 평가를 위해 리커트척도(Likert scale)를 적용하여 사후평가 하였다. 효용성분석 결과 전체 37기 중 영도등대, 가거도등대, 거문도등대, 죽변등대의 기능 및 효용성이 높은 것으로 분석되었으며, 울릉도등대, 가사도등대, 송대말등대, 울기등대의 경우 세부적인 적정성분석이 이루어질 필요가 있는 것으로 분석되었다. 이러한 항로표지시설 효용성분석은 항로표지시설의 관리체계의 효율성 향상, 항로표지의 재배치 및 정책결정을 위한 기초자료 등으로 활용할 수 있을 것이다.
이 연구에서는 2014년 6월 10일 일산에서 발생한 용오름에 대해 구름분해모델(CReSS)를 활용하여 재현실험을 수행하고 발생 메커니즘을 분석하였다. 종관적으로는 대기 상층의 한랭하고 건조한 공기가 남하하였으며, 대기 하층에서는 온난하고 습윤한 공기의 이류가 있었다. 이로 인해 대기 상 하층 기온의 큰 차이가 발생하면서 강한 대기 불안정을 야기 시켰다. 19시 20분에 일산 지역에서 스톰이 발달하기 시작하여 10분 만에 최성기에 도달하였다. 재현 실험 결과 이 때 발달한 스톰의 높이는 9 km이었으며, 스톰 후면으로 갈고리 에코(hook echo)가 나타났다. 일산 주변으로 발달 한 스톰 내부에서는 활강 기류가 발생하는 것으로 모의 되었다. 모의된 하강기류가 지면에서 발산되어 수평 흐름으로 변하게 되었고, 이 흐름은 스톰의 후면에서 상승류로 전환 되었다. 이 때 후면에서 강한 하강기류가 발생하였는데 이 하강류가 전환된 상승류를 지면까지 끌어내려 지면에서 소용돌이도가 발달하게 되었다. 그 이후 이 소용돌이도가 연직으로 신장되면서 용오름이 모의되었다. 모의된 용오름에서 발달한 저기압성 소용돌이도는 360 m 고도에서 3×10−2 s−1이 었으며, 용오름의 직경은 900 m 고도에서 1 km로 추정되었다.