• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1063-1069
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• 2016

• KSBB Journal
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• 제9권1호
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• pp.40-47
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• 1994

Fructosyltransferase와 glucose oxidase의 혼합효소계를 이용한 고순도 fructo-oligosaccharides 생산반응에서의 수학적 모델을 제안하고 실험적으로 검증한 결과 실험치와 모델 값이 서로 잘 일치하였다. 혼합 효소계에서 두 효소의 kinetic parameters를 구한 결과, fructosyltransferase 단일 효소계에서의 값들에 비해 $K_m$ 값들은 감소하였고, $K_m,\;V_{max}$값들은 증가하였다. 혼합 효소계의 반응메카니즘은 전체적으로 Michaelis-Menten kinetics로 표현할 수 있었고, 제안된 모델을 이용하여 고순도 fructo-oligosaccharides 생산에 이상적인 설탕농도를 예측할 수 있었다.

• 한국시뮬레이션학회논문지
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• 제32권4호
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• pp.11-18
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• 2023

본 연구는 자동차 공장의 혼류생산을 위한 자동창고시스템에서 저장과 반출 작업을 수행하는 트윈크레인 간 협업(Handshake) 위치 시뮬레이션 분석을 수행한다. Handshake 운영은 트윈크레인의 작업영역 구분을 통해 경로 간섭과 각 크레인의 이동 거리를 개선한다. 그러나 Handshake 위치로 구분된 작업영역 간 부품 이송을 위해 Handshake 위치에서 추가적인 부품 적재와 하역 작업이 발생한다. 그러므로 저장 및 반출 요청 응답시간을 개선하기 위한 효과적인 Handshake 위치 결정이 필요하다. 시뮬레이션 실험을 통해 최적 Handshake 위치를 결정하였으며 평균 입고 요청 응답시간이 87% 개선됨을 확인하였다.

• 한국항해학회지
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• 제22권4호
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• pp.15-19
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• 1998

This paper concerns a bulk or semibulk cargo ship scheduling problem with a single loading port. This type of ship scheduling problem is frequently needed in real world for carrying minerals or agricultural produce from a major single production zone to many destinations scattered over a large area of the world. The first optimization model for this problem was introduced by Ronen (1986) as a nonlinear mixed integer program. The model developed in this paper is an improvement of his model in the sense that nonlinearities and numerous unnecessary integer variables have been eliminated. By this improvement we could expect real world instances of moderate sizes to be solved optimal solutions by commercial integer programming software. Similarity between the ship scheduling model and the capacitated facility location model is also discussed.

• Industrial Engineering and Management Systems
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• 제13권4호
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• pp.369-382
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• 2014

This paper introduces a new multi-product multi-period multi-objective aggregate production planning problem. The proposed problem is modeled using multi-objective mixed-integer mathematical programming. Three objective functions, including minimizing total cost, maximizing customer services level, and maximizing the quality of end-product, are considered, simultaneously. Several constraints such as quantity of production, available time, work force levels, inventory levels, backordering levels, machine capacity, warehouse space and available budget are also considered. Some parameters of the proposed model are assumed to be qualitative and modeled using fuzzy sets. Then, a fuzzy goal programming approach is proposed to solve the model. The proposed approach is applied on a real-world industrial case study of a color and resin production company called Teiph-Saipa. The approach is coded using LINGO software. The efficacy and applicability of the proposed approach are illustrated in the case study. The results of proposed approach are compared with those of the existing experimental methods used in the company. The relative dominance of the proposed approach is revealed in comparison with the experimental method. Finally, a data dictionary, including the way of gathering data for running the model, is proposed in order to facilitate the re-implementation of the model for future development and case studies.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2001년도 추계학술발표회
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• pp.137-144
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• 2001

A Plankton ecosystem model was developed to investigate effects of hydrodynamic processes including advection and diffusion on size-structured phytoplankton dynamics in the mesohaline zone of the York River estuarine system, Virginia, USA. The model included 12 state variables representing the distribution of carbon and nutrients in the surface mixed layer. Groupings of autotrophs and heterotrophs were based on cell site and ecological hierarchy Forcing functions included incident radiation, temperature, wind stress, mean How and tide which includes advective transport and turbulent mixing. The ecosystem model was developed in FORTRAN using differential equations that were solved using the 4th order Runge-Kutta technique. The model showed that microphytoplankton blooms during winter-spring resulted from a combination of vertical advection and diffusion of phytoplankton cells rather than in-situ production in the lower York River estuary.

• 한국수자원학회논문집
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• 제48권1호
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• pp.23-35
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• 2015

본 연구에서는 3차원 수치모형을 이용하여 염수 대수층 내 담수 주입량에 따른 주입정과 양수정 사이의 담수체의 거동을 수치적으로 분석하였다. 대수층 내에 8개의 주입정이 동심원 상에 등간격으로 배열되어 있으며, 동심원 중심에 한 개의 양수정이 위치해 있다. 주입량이 상대적으로 작은 경우 주입정 주변의 담수체는 인근의 주입정에서의 담수체와 서로 혼합되지 않고 독립적으로 분포한다. 그러나 주입량이 증가함에 따라 담수체의 크기는 점차적으로 증가하며, 주입정과 주입정 사이에 염수와 담수가 혼합되어 있는 영역이 나타난다. 혼합되는 정도는 주입량이 증가함에 따라 증가되며, 이러한 현상은 양수정 주변에서도 동일하게 나타난다. 또한주입량이 증가할수록 양수정 주변 및 내에서의 염수비율이 점차적으로 감소하는 경향을 나타내었다.

• 전기학회논문지
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• 제57권4호
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• pp.692-699
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• 2008

Semiconductor research and development(R&D) fabs are very different than production fabs in many ways such as the scales of production, job priority, production methods, and performance measures. Efficient operations of R&D fabs are very important to the development of new product, process stability, high yield, and ultimately company competitiveness. This paper proposes the fab-wide scheduling method for operational optimization of the R&D fabs. Most scheduling systems of semiconductor fabs have only focused on maximizing throughput of each separated areas without considering WIP(works in process) flows of entire fab. In this paper, we proposes the a fab-wide scheduling system which schedules all lots to entire fab equipment at once. We develop the MIP(mixed integer programing) model which allocates the lots to production equipment considering many constraints of all processes and the CP(constraint programming) model which determines the sequences of the lots in the production equipment. The proposed FAB-wide scheduling model is applied to the newly constructed R&D fab. As a result, we have accomplished the system based automated job reservation, decrease of the hot lot delay, increase of the queue time satisfaction, the high throughput by maximizing the batch sizes, decrease of the WIP TAT(Turn Around Time).

• 대한산업공학회지
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• 제25권3호
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• pp.310-320
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• 1999

A mixed model assembly line (MMAL) is a special type of production line where a variety of product models similar in product characteristics are assembled. Determining the model sequence is an important problem for the efficient use of MMALs. This paper considers interactive multiobjective decision making problems for MMAL sequencing. Evolution program is employed as an underlying framework. In this study, a way of approximating the linear utility function is first studied. To improve its search efficiency to the solution space preferred by a decision maker, some modifications of a standard evolution program are made: operating several subpopulations instead of a single population and merging two or more subpopulations to a single subpopulation, and using a Pareto pool. Extensive computational experiments are carried out to verify the performance of the proposed approach. The computational results show that our approach is promising in solution quality.

• 한국약용작물학회지
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• 제18권1호
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• pp.15-21
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• 2010

This study was conducted to investigate the effects of Lycii fructus and Astragalus membranaceus mixed extracts on immunomodulators and prevention in a streptozotocin-induced diabetes rat model. A total of 28 male rats were divided into four dietary groups and fed a commercial diet (A), commercial diet plus induced diabetes by a streptozotocin (STZ) injection (B), induced diabetes by STZ plus medicinal crop extracts(I&$H^{(R)}$) diet (C), and medicinal crop extracts (I&$H^{(R)}$) diet (D). Immunoblotting analyses revealed cytokine expression, and ELISA analyses revealed immunoglobulin E and nitric oxide production. As a results, the tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and inducible nitric oxide synthase (iNOS) as a inflammatory cytokine were decreased. Interleukin-6 (IL-6) and signal transducer and activation of transcription 3 (STAT3) cytokine related in diabetes expression through JAK/STAT3 pathway were also decreased. Furthermore, immunoglobulin E and nitric oxide production were decreased in the serum and lens, respectively. These results suggest that Lycii fructus and Astragalus membranaceus mixed extracts provide positive effects on immunomodulators and prevention in diabetes and eye disease complications.