• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.223-224
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• 2008

Important element are low cost, high-efficiency crystalline silicon solar cells. in this paper, Will be able to contribute in low cost, high-efficiency silicon solar cells, Applies oxide/nitride passivation, produced screen-printed solar cells. and the Measures efficiency, and evaluated a justice quality oxide/nitride passivation screen-printed solar cells.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.141-142
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• 2019

As part of the recent low-energy policy, insulation standards for buildings are increasing every year. In addition, the conventional styrofoam heat insulation material has a problem in that the thickness of the heat insulation material to achieve the standard heat transmission rate is rapidly increased. Although the risk of spreading the structure vulnerable to fire due to insufficient spacing between buildings due to thickened insulation is increasing, the high cost of high efficiency insulation is difficult to solve. On the other hand, it is known that the method to be used as a formwork using insulation is excellent in cost reduction effect by reducing the amount of formwork used and simplifying the subsequent insulation work. The purpose of this study is to evaluate the strength characteristics of multi - layered insulation materials with appropriate strength by reducing the thickness of the insulation by appropriately combining high performance phenolic foam insulation and styrofoam insulation.

• Journal of Construction Engineering and Project Management
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• 제7권3호
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• pp.15-25
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• 2017

The existence of material price volatility in construction projects puts forward substantial risks for all parties involved. Depending on the parties involved in the project, type of contracts, and state of the market various risk management strategies are practiced by contracting parties to manage project risks related to price volatility. Unfortunately, in many cases companies fail to select an adequate approach to better manage volatilities of material prices due to the lack of a decision support system to aid in the selection of an appropriate strategy based on the project characteristics. The aim of this study is to identify critical project factors and align them to documented strategies to manage price volatility based on an extensive literature review and industry interviews. This study found Integrated Project Delivery (IPD) as the ideal strategy with respect to project duration; quantitative risk management methods with respect to the cost; and Price Adjustment Clauses (PAC) with respect to the risk allocation, as the top price volatility management strategies.

• Steel and Composite Structures
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• 제6권5호
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• pp.435-457
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• 2006

The paper presents the cost optimization of composite floor trusses composed from a reinforced concrete slab of constant depth and steel trusses consisting of hot rolled channel sections. The optimization was performed by the nonlinear programming approach, NLP. Accordingly, a NLP optimization model for composite floor trusses was developed. An accurate objective function of the manufacturing material, power and labour costs was proposed to be defined for the optimization. Alongside the costs, the objective function also considers the fabrication times, and the electrical power and material consumption. Composite trusses were optimized according to Eurocode 4 for the conditions of both the ultimate and the serviceability limit states. A numerical example of the optimization of the composite truss system presented at the end of the paper demonstrates the applicability of the proposed approach.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.307-314
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• 2018

In this paper, analytical modeling of lift and drag forces in permanent magnet electrodynamic suspension systems (PM EDSs) are presented. After studying the impacts of PM dimensions on the permanent magnetic field and developed lift force, it is indicated that there is an optimum PM length in a specified thickness for a maximum lift force. Therefore, the optimum PM length for achieving maximum lift force is obtained. Afterward, an objective design optimization is proposed to increase the lift force and to decrease the material cost of the system by using Genetic Algorithm. The results confirm that the required values of the lift force can be achieved; while, reducing the system material cost. Finite Element Analysis (FEA) and experimental tests are carried out to evaluate the effectiveness of the PM EDS system model and the proposed optimization method. Finally, a number of design guidelines are extracted.

• 한국안전학회지
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• 제17권4호
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• pp.1-4
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• 2002

A automatic production system was developed for high productivity and safety. The semi-progressive die was unfavorable for more productivity, safety, material extravagance and incongruent high-speed production. Developed progressive die is suitable for the high production and guarantee triple production by acceptance of three array type for automobile adjust plate. We adopt Pro-$Engineer{\circledr}$ for three dimensional computer aided design suitable for the disassembly and assembly evaluation. The conclusion of this study is as follow. First, press die parts solid modeling system is built by using Pro-$Engineer{\circledr}$ through this research and verified allowable tolerance and possibility of assembly and disassembly of parts. Therefore we can reduce die manufacturing time and cost. Second, We produce 1000 units pet hot coil 1ton by traditional method, but we can acomplish material saving effect about 12% as 120 units in case of new progressive die. Fourth, we acomplished manufacturing cost curtailment effect more than 20% in comparison with traditional method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.589-592
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• 2001

In this paper, Electronic ballast for multiple fluorescent lamps based on the use of ferrite beads are presented. The use of this system in place of the conventional electromagnetic ballast results in lower power consumption and reduced maintenance cost, because the electronic system has higher efficiency and longer lamp lifetime than the electromagnetic ballast. In comparison with the conventional electronic ballast. The proposed system presents a significant reduction of cost. This reduction becomes were meaningful with the growing of the lamp number. The description of the lighting system, We show that the proposed model can be applied to multiple lamps electronic ballast by simulation processes.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계합동학술대회 논문집
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• pp.62-67
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• 2002

A single-phase power factor corrected converter for switched reluctance motor driving is presented to achieve sinusoidal, near unity power factor input currents. Because it combines a power factor corrected converter and a conventional asymmetric SRM driver into one power stage, the configuration has a simple structure resulted in low cost. A prototype to drive 6/6 poles SRM employing a parking magnet is designed to evaluate the proposed topology. The characteristics and operational mode will be discussed in depth, and the validity of proposed driver will be verified through the experimental results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.558-559
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• 2007

A commercially de-waxer which kinds of solvent after was used to remove a thick organic wax film after polishing process and several steps of SC-1 cleanings were followed for the removal of organic wax residues and particles which requires long process time and high cost of ownership (COO). DIO3 was used to remove organic wax residues too achieve low COO. In this study, 0103 rinsing could use instead of 01 water rinsing. The process time and chemical consumption were reduced by using DIO3.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.229-231
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• 2005

HVDC(High Voltage Direct Current) is an underwater cable between Jeju Island and Haenam in main land and supplies approximately 50% of electrical usage in Jeju Island. If there is any power failure due to HVDC, it will cost approximately 50,000 US dollars per day including Thermal Electrical Generation. Therefore it is absolutely necessary to recover the problem in rapid timely basis. In conclusion, evaluation methode of HVDC cable is needed urgently to upgrade current HVDC underwater cable repair technique in Korea to minimize the cost and time factors.