• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.120-125
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• 2002

In this paper, we propose a new ordering model for the mixed parts transportation problem with multi-items based on the depot system. Order scale are used as decision parameters instead of order point for ordering multi-items. Finally we test the model with simple example and show computational result that verifies the effectiveness of the model.

• Industrial Engineering and Management Systems
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• v.6 no.2
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• pp.136-145
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• 2007

The selection of suppliers and the determination of order quantities to be placed with those suppliers are important decisions in a supply chain. In this research, a non-linear mixed integer programming model is presented to select suppliers and determine the order quantities. The model considers the purchasing cost which takes into account quantity discount, the cost of transportation, the fixed cost for establishing suppliers, the cost for holding inventory, and the cost of receiving poor quality parts. The capacity constraints for suppliers, quality and lead-time requirements for the parts are also taken into account in the model. Since the purchasing cost, which is a decreasing step function of order quantities, introduces discontinuities to the non-linear objective function, it is not easy to employ traditional optimization methods. Thus, a heuristic algorithm, called particle swarm optimization (PSO), is used to find the (near) optimal solution. However, PSO usually generates initial solutions randomly. To improve the PSO solution quality, a heuristic procedure is proposed to find an initial solution based on the average unit cost including transportation, purchasing, inventory, and poor quality part cost. The results show that PSO with the proposed initial solution heuristic provides better solutions than those with PSO algorithm only.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.461-470
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• 2020

The objective of this research is to examine the factors affecting the decision-making of International Commercial Terms (Incoterms) of automotive parts manufacturers in Thailand. This mixed method study applied qualitative and quantitative research methods and utilized the analytical hierarchy process (AHP) to prioritize the significance of the factors. By an in-depth literature review and expert interview, four main criteria were identified. These criteria include Operating costs, Cooperation and bargaining power, Knowledge and understanding and Operation duration then main criteria divided into fifteen sub-criteria. The common Incoterms, Ex Works (EXW), Free On Board (FOB), Free Carrier (FCA), and Cost, Insurance and Freight (CIF), were determined as alternatives to the incoterms through a preliminary survey. The results revealed that the operating costs were the most important factor for the company. Moreover, it was discovered that this was consistent with the priority of the secondary factors, which included the annual budget for the transportation expenses and product value at one time. The respondents' perspective suggested that FCA was the most appropriate Incoterms for international trade for a company. The findings of this research suggest a hierarchy model for organizations to prioritize the significant factors in order to make a decision on the most appropriate Incoterms.

• Journal of Power System Engineering
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• v.21 no.4
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• pp.94-99
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• 2017

Single walled carbon nanotubes were mixed with various metal powders by mechanical ball milling and sintered by spark plasma sintering processes. Two compositional (0.1 and 1 vol%) of the single walled carbon nanotubes were dispersed onto the pure aluminum, 5052 aluminum alloy, pure titanium, Ti6Al4Vanadium alloy, pure copper, and stainless steel 316L. Each composite powders were spark plasma sintered at $600^{\circ}C$ and well synthesized regardless of the matrices. Vickers hardness of the composite materials was measured and they exhibited higher values regardless of the carbon nanotubes composition than those of the pure materials. Moreover, single walled carbon nanotubes reinforced copper matrix composites showed highest enhancement between the other metal matrices system. We believe that low energy mechanical ball milling and spark plasma sintering processes are useful tool for fabricating of the carbon nanotubes-reinforced various metal matrices composite materials. The single walled carbon nanotubes-reinforced various metal matrices composite materials could be used as an engineering parts in many kind of industrial fields such as aviation, transportation and electro technologies etc. However, detail strengthening mechanism should be carefully investigated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.647-662
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• 2015

This study analyzes the factors that influence the number of public transportation passengers. By comparing the major TOD planning elements such as mixed-use level, job-housing proximity level, comparison of the density and pure density in the 66-autonomous city townships through a comparison such as TOD plan element achievements and indicators are chosen. A model is derived by correlation analysis and regression analysis of the parameters. The result of the regression analysis of the station influence area (SIA) in Incheon, the parameters that effect the number of passengers of public transportation are the number of employees, population, number of bus stops in the SIA, and the distance between the bus stop and the subway entrance. Therefore, as the number of employees and the resident population increase, the volume of traffic increases. Also, the number of public transportation users increases when there are more bus stops and when the distance between the bus stop and the subway entrance is short. This study shows that subways and SIA has achieved many parts of the TOD in Incheon, because the SIA around 29 subways and 11 Seoul-Incheon trail stations already included important TOD planning elements.

• Journal of Welding and Joining
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• v.34 no.1
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• pp.59-67
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• 2016

The automotive manufactures increase their use of lightweight materials to improve fuel economy and energy usage has a significant influence on the choice of developing materials. To meet this requirements manufacturers are replacing individual body parts with lightweight metals, for these the process treating and painting surfaces is changing. The pre-coated steels are newly developed to avoid the conventional complex and non-environmental painting process in the body-in-white car manufacturing. The development of new joining techniques is critically needed for pre-coated steel sheets, which are electrically non-conductive materials. In the present study, dissimilar combination of pre-coated steel and galvanized steel sheets were joined by the self-piercing rivet, adhesive bonding and hybrid joining techniques. The tensile shear test and free falling high speed crash test were conducted to evaluate the mechanical properties of the joints. The highest tensile peak load with large deformation was observed for the hybrid joining process which has attained 48% higher than the self-piercing rivet. Moreover, the hybrid and adhesive joints were observed better strain energy compared to self-piercing rivet. The fractography analyses were revealed that the mixed mode of cohesive and interfacial fracture for both the hybrid and adhesive bonding joints.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.6
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• pp.220-225
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• 2020

Gallium oxide nano-powder, the key starting material for IGZO target, is fabricated by gas phase synthesis using a new apparatus consist of reaction, transportation, and collection parts. As a result of gallium metal evaporation above 1150℃, Ga2O3 nano-powders, are successfully synthesized. The SEM images of the synthesized powders displace the spherical shaped powders without severe agglomeration. X-ray diffraction and PSA analysis show that the higher temperature at the reaction part results in the better crystallinity and larger powder size of the synthesized Ga2O3. To see the applicability to IGZO target, Ga2O3 nano-powders synthesized at 1250℃ are mixed with indium oxide and zinc oxide (In2O3 : Ga2O3 : ZnO = 1 : 1 : 1), and then sintered at 1400~1500℃. The highest sintered density of 5.83 g/㎤ (= 91 % of relative density) is achieved when sintered at 1450℃, showing better sinterability compared to the commercially available Ga2O3 powder, which has 5.61 g/㎤ of sintered density at the same condition.