• 한국시뮬레이션학회논문지
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• 제28권2호
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• pp.107-117
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• 2019

조선업은 한정된 자원을 사용하는 single-product production방식이며, 리소스를 효율적으로 관리하여 선박 공정의 생산성을 극대화 시킬 수 있는 생산관리기술이 중요하다. 때문에 많은 조선사에서는 모델링 및 시뮬레이션을 적용함으로써 현장 내 다양한 제약 조건이 고려된 선박 생산계획 및 공정에 대한 연구를 수행하고 있다. 하지만 기존 연구들은 갑작스런 일정 및 공정변경 시 정확한 생산계획을 제공하기 어려우며, 블록을 생산하는 각 공정 간의 상호연관성 파악이 어렵다. 뿐만 아니라, 블록의 세부 공정 및 일량을 고려하지 못하였기 때문에 생산계획과 현장계획에 많은 차이가 발생한다. 본 연구에서는 조선 내업공정 내 스케줄 된 전체 블록의 공정작업 순서 및 설계정보, 그리고 자원 제약을 고려하는 모델링 방법인 통합 프로세스 기반 모델 설계 방법을 제시한다. 통합 프로세스 기반 모델을 통해 사용자는 내업공정 내 블록 간의 조립관계, 정반정보 및 조립공정의 선후관계 파악이 용이하다. 또한 조선 내업공정에서 공유하는 리소스의 일량을 고려하여 부하 평준화를 진행하기 때문에 별도의 시뮬레이션 및 리소스의 모델링 절차 없이 리소스 효율을 최대화 할 수 있는 전체 생산계획을 얻을 수 있다.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.311-314
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• 2005

Supply chain optimization is one of the most important components in the optimization of a company's value chain. This paper considers the problem of designing the supply chain for a product that is represented as an assembly bill of material (BOM). In this problem we are required to identify the locations at which different components of the product arc are produced/assembled. The objective is to minimize the overall cost, which comprises production, inventory holding and transportation costs. We assume that production locations are known and that the inventory policy is a base stock policy. We first formulate the problem as a 0-1 nonlinear integer programming model and show that it can be reformulated as a 0-1 linear integer programming model with an exponential number of decision variables.

• 산업경영시스템학회지
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• 제43권2호
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• pp.72-78
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• 2020

Demand for cosmetics with functionality and eco-friendliness has increased dramatically due to recent aging, well-being trends, and increased interest in beauty. Cosmetics production in 2014 was 8,970.4 billion won, an increase of about 50% compared to 6,014.6 billion won in 2010. In the midst of this, similar companies in intense competition are pursuing differentiated strategies and innovation activities to solve quality, price and delivery problems. In particular, cosmetics packaging work is getting more difficult due to the increasing bill of materials (BOM) and difficult assembly methods. Therefore, in this study, the following problems were identified and suggestions for the improvement of the packaging Many research laboratories such as biotechnology, chemistry, and pharmaceuticals, which are undergoing various studies, are equipped with ready-made laboratory safety equipments such as bio-safety workbenches, aseptic bases, and exhaust workbenches. However, most researchers are disadvantaged in using existing safety equipment. This is because existing safety equipment can not take into account all of the unique characteristics of the research. For this reason, researchers are demanding the development of customized safety equipment that is well suited to their research needs. process of Company C, which is facing difficult situation to respond to the customer 's delivery due to the 52 - hour work week. First, we used the stopwatch to find the difficulty process in the packaging process and show ways to improve it. Second, to improve the efficiency of line balancing in the packaging process, we integrate processes, improve work methods, and perform simple automation. As a result, the prepare loss for replacement was reduced by 1 minute from 5 minutes, resulting in a 23% increase in productivity from 112 ea./hour to 137ea./ hour per person. At this time, the LOB of the packaging process was improved from 70% to 82% by operating one more production line through one person per line, total 9 people saving.

• 한국재료학회지
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• 제19권5호
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• pp.233-239
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• 2009

The electrocatalytic behavior of the PtCo catalyst supported on the multi-walled carbon nanotubes (MWNTs) has been evaluated and compared with commercial Pt/C catalyst in a polymer electrolyte membrane fuel cell(PEMFC). A PtCo/MWNTs electrocatalyst with a Pt:Co atomic ratio of 79:21 was synthesized and applied to a cathode of PEMFC. The structure and morphology of the synthesized PtCo/MWNTs electrocatalysts were characterized by X-ray diffraction and transmission electron microscopy. As a result of the X-ray studies, the crystal structure of a PtCo particle was determined to be a face-centered cubic(FCC) that was the same as the platinum structure. The particle size of PtCo in PtCo/MWNTs and Pt in Pt/C were 2.0 nm and 2.7 nm, respectively, which were calculated by Scherrer's formula from X-ray diffraction data. As a result we concluded that the specific surface activity of PtCo/MWNTs is superior to Pt/C's activity because of its smaller particle size. From the electrochemical impedance measurement, the membrane electrode assembly(MEA) fabricated with PtCo/MWNTs showed smaller anodic and cathodic activation losses than the MEA with Pt/C, although ohmic loss was the same as Pt/C. Finally, from the evaluation of cyclic voltammetry(CV), the unit cell using PtCo/MWNTs as the cathode electrocatalyst showed slightly higher fuel cell performance than the cell with a commercial Pt/C electrocatalyst.