• 전기학회논문지
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• 제59권5호
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• pp.897-903
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• 2010

This paper presents a response surface method(RSM) with Latin Hypercube Sampling strategy, which is employed to optimize a magnet pole shape of large scale BLDC motor to minimize the cogging torque. The proposed LHS algorithm consists of the multi-objective Pareto optimization and (1+1) evolution strategy. The algorithm is compared with the uniform sampling point method in view points of computing time and convergence. In order to verify the developed algorithm, a 6 MW BLDC motor is simulated with 4 design parameters (arc length and 3 variables for magnet) and 4 constraints for minimizing of the cogging torque. The optimization procedure has two stages; the fist is to optimize the arc length of the PM and the second is to optimize the magnet pole shape by using the proposed hybrid algorithm. At the 3rd iteration, an optimal point is obtained, and the cogging torque of the optimized shape is converged to about 14% of the initial one. It means that 3 iterations aregood enough to obtain the optimal design parameters in the program.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.967-972
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• 2009

A dynamic model has been developed to investigate the operability of a single and double-effect solar energy assisted parallel type absorption chiller. In the study, main components and fluid transport mechanism were modeled. And solar radiation and the solar collector also were also modeled along with its control design. The model was run for the single mode with solar energy supply only and the solar/gas driving double effect mode. From the simulation results, it was found that the present configuration of the chiller is not capable of regulating solution flow rates according to variable solar energy input. And the issues of the excessive circulation flowrate and the mismatch between available solar power and cooling load discourages the use of the single mode, but the dual use of gas and solar power is recommendable in view of controllability and enhanced COP.

• 조명전기설비학회논문지
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• 제17권5호
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• pp.141-148
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• 2003

최근 자동제어 시스템의 다양한 분야에서 선형운동용 디지털 액튜에이터인 하이브리드형 선형 스텝핑 전동기(HLSM)의 필요성이 증대되고 있다. HLSM은 기계적인 운동변환기구가 필요하지 않는 직접 구동방식이기 때문에 효율과 경제적인 측면에서 회전형 스텝핑 전동기에 비해 매우 유리한 장점이 있다. 본 논문에서는 현재 가장 많이 연구되고 있는 자속종방향(LFM)형 HLSM의 개발을 위하여 2차원 유한요소법(FEM)으로 최적의 치 형상을 설계하고 추력과 수직력을 계산하였다. 그리고 직접 LFM형 HLSM의 시작기를 제작하고, LFM형 HLSM의 추력 특성을 실험하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 춘계 학술논문 발표대회
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• pp.147-151
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• 2008

Construction project is completed through several stages and problems of each stage affect directly not only now but also next. Defect of 2D drawings influence in construction phase, and it make many loss on project. Nowadays we practically use real Mock-up test in construction sites to solve the problems. But it also has many problems which are waste much money and time. Therefore, this study tries to analyze effect that is occurred by appling BIM Mock-up simulation instead of real Mock-up execution. These analysis is conducted by comparing two construction building site. These have same shape but one is made for BIM Mock-up, and another is real Mock-up. Comparison points of view are cost, time and operator's satisfaction. It is expect that BIM Mock-up is more effective at low cost and on shorter time. But our analysis show that each are conducted different part of function. So new Mock-up type is required. Hybrid Mock-up is combine real mock-up with BIM simulation and it can minimize risk of project.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.98-105
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• 2014

As environmentally friendly energy takes center stage, interests for Electric Vehicles/Plug in Hybrid Electric Vehicles (EVs/PHEVs) are getting increase. With this trend, there is no doubt EVs will take large portion to penetrations of total cars. Therefore, accurate EV modeling is required. Battery is one of the main components with the power system view of aspect. Hence, in this paper, reviews and discussions of some types of batteries for EV are contained by considering energy density and weight of the batteries. In addition, simulations of Li-Ion battery are accomplished with various variables such as temperature, capacity fading and charge/discharge current. It is confirmed that temperature is the main factor of capacity fading. Validation of the modeled battery is also conducted by comparing it with commercialized battery.

• 한국식물병리학회지
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• 제13권2호
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• pp.95-99
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• 1997

To obtain a basic information of breeding for resistance to clubroot in Chinese cabbage, disease incidence, pathogenicity, and varietal response to the pathogen were studied. Incidence of clubroot was observed at 3 districts in Gyeonggi-Do, 2 districts in Kangwon-Do, and 1 district each in Gyeongnam, Geongbuk and Jeonbuk, respectively. Disease infection rate and diseased ara were most severe in northern part of Gyeonggi-Do. The isolates of clubroot collected from 8 different districts were not different in their virulence one another in view of their infection rate and disease severity in Chinese cabbage. The clubroot fungus had a wide host range for the cruciferous vegetables. Disease severity was high in rape, turnip and mustard, moderate in Chinese cabbage and broccoli, and low in kale and cauliflower. All of Korean hybrids of Chinese cabbage tested were highly susceptible to clubroot, but Japanese varieties were resistant to the highly pathogenic isolate (EJ-93) which was isolated from the Chinese cabbage in Korea. The hybrid(F1) between clubroot resistant line(930WG) and the susceptible line(332MS) showed completely resistant reaction, which indicated that clubroot resistance was governed by a dominant gene.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4372-4388
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• 2014

Robotic sensor network (RSN) contains mobile sensors and robots providing feasible solution for many multi-agent applications. One of the most critical issues in RSN and its application is how to effectively assign tasks. This paper presents a novel connectivity preserving hybrid task allocation strategy to answer the question particularly for RSN. Firstly, we model the task allocation in RSN to distinguish the discovering and allocating processes. Secondly, a fully distributed simple Task-oriented Unoccupied Neighbor Algorithm, named TUNA, is developed to allocate tasks with only partial view of the network topology. A connectivity controller is finally developed and integrated into the strategy to guarantee the global connectivity of entire RSN, which is critical to most RSN applications. The correctness, efficiency and scalability of TUNA are proved with both theoretical analysis and experimental simulations. The evaluation results show that TUNA can effectively assign tasks to mobile robots with the requirements of only a few messages and small movements of mobile agents.

• 천문학회보
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• 제36권2호
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• pp.92.2-92.2
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• 2011

In view of the planned NASA's and ESA's Solar Probe Plus and Solar Orbiter missions, respectively, to probe the inner heliosphere and the Sun's corona, it is timely to investigate outstanding problems associated with the solar wind. Among them is the temperature anisotropy problem. As the solar wind expands into the interplanetary space, the density and magnetic field decreases radially, thus leading to temperature anisotropy ($T_{\parallel}{\gg}T_{\perp}$). However, the measured temperature anisotropy can at times be characterized by $T_{\perp}$ > $T_{\parallel}$, while at other times the measured $T_{\parallel}/T_{\perp}$ is much milder than predicted by adiabatic theory. Physical reasons remain poorly understood. This notwithstanding, it is known from plasma physics that for $T_{\perp}$ > $T_{\parallel}$ electromagnetic ion-cyclotron (EMIC) and mirror instabilities are excited, while for $T_{\parallel}$ > $T_{\perp}$, fire-hose instability is excited. By constructing the threshold conditions for various instabilities, one may construct a closure relation that may be useful for modeling the solar wind. In the present paper we discuss theoretical construction of the anisotropy-beta relation by means of quasi-linear theories of these instabilities. The present work complements previous efforts on the basis of linear theory, hybrid simulations, and empirical fits of observations.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.540-545
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• 2008

An atrium has great potential in natural ventilation aided by buoyance effect. Architectural design of an atrium is very critical to maximize the effect. However, it is not easy of an atrium to have optimum shape for natural ventilation, from the aesthetic and economic point of view. Admitting this condition, we suggested a strategy to promote natural ventilation, which can be adopted only with small design change. At first, we installed BIPV on the top of an atrium to strengthen buoyancy effect, and combine forced ventilation by low pressure fan. To evaluate the performance of the measure, CFD simulation and Energy-Airflow analysis were achieved.

• Plant Resources
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• 제5권1호
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• pp.45-50
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• 2002

Korean cultivars of buckwheat(Fagopyrum esculentum Moench.) was crossed with Canadian cultivars in order to improve seed yield as well as leaf production of buckwheat for using as food and medicine. The agronomic characteristics and rutin contents of F$_2$ hybrids are investigated for further selection of superior lines. Dry weight per plant was the highest in a line 1110(6.71g) and leaf weight per plant was the highest in a line 1110(1.91g). Hybrid seeds were 0.55 - 0.70cm long and 0.37 - 0.47cm wide on average. 100 seeds weight ranged from 2.57g to 3.58g. Line 1076 produced the longest seeds(0.70cm) and line 1186 was the longest in seed width. Line 1196 showed the highest 100 seeds weight(3.58g). The highest frequency of the LWR(length/width rate) was 0.66~0.70, indicating that seed shape of the hybrids was mostly oval. Line 1087 showed the highest contents of rutin(77.26ppm). Lines 1090 and 1181 contained respectively rutin of 54.76ppm and 54.35ppm in the seeds. From the yield and rutin point of view, the most superior lines was line 1087 among the lines used for this study.