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반응면기법을 이용한 PBMR 기체냉각형 고온가스로 상층부의 최적설계
이상문(S.M. Lee),김광용(K.Y. Kim) 한국전산유체공학회 2010 한국전산유체공학회지 Vol.15 No.3
Shape optimization of an upper plenum of a PBMR type gas cooled nuclear reactor has been performed by using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) analysis and surrogate modeling technique. The objective function is defined as a linear combination of uniformity of flow distribution in the core and pressure drop in the upper plenum and the core. The ratio of thickness of slot to diameter of rising channels, ratio of height of upper plenum to diameter of rising channels, and ratio of height of the slot at inlet to outlet, are used as design variables for optimization. Design points are selected through Latin-hypercube sampling. The optimal point is determined through surrogate-based optimization method which uses 3-D RANS analyses at design points. The results show that the optimum shape represent remarkably improved performance in flow uniformity and friction loss than the reference shape.
이상문(S. M. Lee) 대한전기학회 2012 전기학회논문지 Vol.61 No.7
This paper considers a model predictive control problem of discrete-time constrained systems with time-varying delay. For this problem, a delay dependent state feedback control approach is used to achieve asymptotic stabilization of systems with input constraints. Based on Lyapunov stability theory, a new stability condition is obtained via linear matrix inequality formulation to find cost monotonicity condition of the model predictive control algorithm which guarantee the closed loop stability. Finally, the proposed method is applied to a numerical example in order to show the effectiveness of our results.
반응면기법을 이용한 PBMR 기체냉각형 고온가스로 상층부의 최적설계
이상문(S.M. Lee),김광용(K.Y. Kim) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5
Shape optimization of an upper plenum of a PBMR type gas cooled nuclear reactor has been performed by using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) analysis and surrogate modeling technique. The objective function is defined as a linear combination of uniformity of flow distribution in the core and pressure drop in the upper plenum and the core. The ratio of thickness of slot to diameter of rising channels, ratio of height of upper plenum to diameter of rising channels, and ratio of height of the slot at inlet to outlet, are used as design variables for optimization. Design points are selected through Latin-hypercube sampling. The optimal point is determined through surrogate-based optimization method which uses 3-D RANS analyses at design points. The results show that the optimum shape represent remarkably improved performance in flow uniformity and friction loss than the reference shape.
유기 조사료 급여 농가의 영양소 균형 및 유생산성 평가
나영준,신기문,임종수,방제용,이상락,Na, Y.J.,Shin, K.M.,Rim, J.S.,Bang, J.W.,Lee, S.R. 한국초지조사료학회 2016 한국초지조사료학회지 Vol.36 No.2
전라북도 고창 조사 지역 내 유기 낙농 농가 수는 연도가 지남에 따라 증가하지 않았지만, 전체적인 사육규모와 사육두수는 증가하였다. 연 평균 유량은 국내 검정 농가 평균에 비해 유기 낙농가가 최대 9 kg/d가 낮았지만 유지방과 유단백 함량에서는 큰 차이를 보이지 않았다. NRC (2001)의 사양표준 프로그램을 이용하여 영양소 공급 수준을 평가한 결과, 급여 사료의 에너지 비율 특히 비구조탄수화물의 비율을 감소시킬 필요가 있으며, 또한 대사단백질 및 섬유소 비율을 증가시켜 전체적인 영양소 공급 수준을 조정한다면 착유우의 건강상태 및 유생산성이 개선될 것으로 생각된다. This study was conducted to evaluate the milk productivity and nutrient balance in organic dairy farms located at Gochang-gun of Korea with different feed sources. The total number of organic dairy farms was 12 in 2012, 13 in 2013, and 14 in 2014. The numbers of farms and dairy herds were increased each year. The average milk yields in 2012, 2013, and 2014 were 25.5, 24.6, and 24.4 kg/d, respectively. The average milk fat contents in 2012, 2013, and 2014 were 3.5%, 3.6%, and 3.7%, respectively. The average milk protein contents in 2012, 2013, and 2014 were 3.3%, 3.4%, and 3.4% in 2012, 2013, and 2014, respectively. Although the average milk yield of organic dairy farms was 9 kg/cows/d less than the average milk yield of other dairy farms in Korea, milk fat and protein contents of organic dairy farms were higher than those of other dairy farms. Alfalfa hay, oat hay, corn silage, rye grass silage, Sudan grass silage, rice straw, and barley silage were commonly used as forage sources in organic dairy farms. The average silage intake (15.6 kg/cow/d) of organic dairy farms in 2013 was higher (P < 0.05), while the average hay intake (5.1 kg/cow/d) in 2014 was higher (P < 0.05) than that of other feed intake. Net energy for lactation ($NE_L$) and metabolizable protein (MP) were calculated in accordance with NRC (2001). Net energy for lactation intake was higher (P < 0.05) while MP intake was lower (P < 0.05) than NRC recommendation values in 2013 and 2014. These results indicate that domestic organic dairy farms should use feed considering energy and protein balance recommended by NRC.
구간 시변 지연을 고려한 전환 멀티-에이전트 시스템에 대한 일치 제어
박명진(M. J. Park),권오민(O. M. Kwon),이상문(S. M. Lee),박주현(Ju H. Park),차은종(E. J. Cha) 제어로봇시스템학회 2012 제어·로봇·시스템학회 논문지 Vol.18 No.5
This paper considers multi-agent systems with interval time-varying delays and switching interconnection topology. By construction of a suitable Lyapunov-Krasovskii"s functional, new delay-dependent consensus control conditions for the systems are established in terms of LMIs (Linear Matrix Inequalities) which can be easily solved by various effective optimization algorithms. One numerical example is given to illustrate the effectiveness of the proposed methods.
Fe2O3 후막을 이용한 alcohol sensor 제작 및 감응특성
이윤수(Y . S . Lee),송갑득(K . D . Song),이상문(S . M . Lee),심창현(C . H . Shim),최낙진(N . J . Choi),주병수(B . S . Joo),이덕동(D . D . Lee),허증수(J . S . Huh) 한국센서학회 2002 센서학회지 Vol.11 No.2
In order to get low cost and portability, semiconductor gas sensor need to have low operating temperature and high sensitivity. Fe_2O_3 based sensors which were doped with metal oxidecatalysts(MoO_3, V_2O_5, TiO_2, and CdO) were fabricated by screen printing method. To improve electrical stability of sensors, the Fe_2O_3 sensors were annealed in N_2 at 700 ℃ for 2 hours. The V_2O_5 doped Fe_2O_3 sensor showed about 80 ~ 90 % sensitivity at alcohol 1,000 ppm and have good selectivity to hydrocarbon gas and tobacco odors. The fabricated sensor and PIC-chip were employed for portable alarm system.