• International Journal of Automotive Technology
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• 제8권3호
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• pp.289-298
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• 2007

A nonlinear dynamic simulation model from cranking to idle speed is developed to optimize the cold start process of a diesel engine. Physically-based first order nonlinear differential equations and some algebraic equations describing engine dynamics and starter motor dynamics are used to model the performance of cold starting process which is very complex and involves many components including the cold start aiding method. These equations are solved using numerical schemes to describe the starting process of a diesel engine and to study the effects of cold starting parameters. The validity of this model is examined by a cold start test at $-20^{\circ}C$. Using the developed model the effects of the important starting variables on the cold starting processes were investigated. This model can be served as a tool for designing computer aided control systems that improve cold start performance.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 반도체재료
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• pp.54-56
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• 2001

The $SiH_4$ soak step is widely used during the CVD Tungsten(W) plug deposition process on the Ti/TiN barrier metal to prevent the $WF_6$ attack to the underlayer metal. We tried to reduce or skip the time of $SiH_4$ soak process to optimize W-plug deposition process on Via. The electrical characteristics including Via resistance and the structure of W film are affected according to $SiH_4$ soak time. The elimination possibility of $SiH_4$ soak process was confirmed in the case of that the CVD W film grows on the stable Ti/TiN underlayer.

• 마이크로전자및패키징학회지
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• 제22권1호
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• pp.1-5
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• 2015

Recently, data throughput of smart electric devices increases dramatically. There is a great interest in a new technology which exceeds the limit of electrical transmission method. Optical PCB can supplement the weakness of electrical signal processing, the research for optical PCB is very active. In this paper, we propose the thermal imprint lithography process to fabrication optical layer of optical PCB and experiment to optimize the process conditions. We confirm process time, pressure, process temperature, demolding temperature and fabricate optical interconnection structure which has $45^{\circ}$ tilted mirror surface for confirm the interconnection efficiency.

• 한국기계가공학회지
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• 제7권2호
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• pp.8-15
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• 2008

Current trend of design technologies shows engineers to objectify or automate the given decision-making process. The numerical optimization is an example of such technologies. However, in numerical optimization, the uncertainties are uncontrollable to efficiently objectify or automate the process. To better manage these uncertainties, Taguchi method, reliability-based optimization and robust optimization are being used. Based on the independence axiom of axiomatic design theory that illustrates the relationship between desired specifications and design parameters, the designs can be classified into three types: uncoupled, decoupled and coupled. To best approach the target performance with the maximum robustness is one of the main functional requirements of a mechanical system. Most engineering designs are pertaining to either coupled or decoupled ones, but these designs cannot currently accomplish a real robustness thus a trade-off between performance and robustness has to be made. In this research, the game theory will be applied to optimize the trade-off.

• 한국태양에너지학회 논문집
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• 제30권5호
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• pp.77-84
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• 2010

This paper presents the continuous commissioning process, information on the case study facility, improved system operation, and building energy consumption measures before and after continuous commissioning implementation. Continuous commissioning is an ongoing process to resolve operating problems, improve comfort, optimize energy use and identify retrofits for existing commercial and institutional buildings and central plant facilities. Continuous commissioning process consists of two phases. The first phase is the project development phase and the second phase implements and verifies project performance. Results of a case study show that continuous commissioning implementation can reduce energy costs. The energy reports show the electricity savings of 22% and gas savings of 47% on an average.

• 산업경영시스템학회지
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• 제33권3호
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• pp.71-78
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• 2010

The end shape of tube for automobile power steering system has influence on the ability of performance. In this case study, we attempted to optimize the forming process of a small tube using Taguchi experimental design methodology. A preliminary experiment was conducted and four main control factors were selected. The experiment was set up as an $L_9(3^4)$ orthogonal array, and determined the optimal levels of the four factors through the analysis of the experimental results. As a result, the performance characteristic(close adhesion power) of the product was improved about 36%. In addition, the process capability index $C_{pk}$ is enhanced from 0.94 to 6.85.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 추계학술대회 논문집
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• pp.106-109
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• 1992

In this study, a single optical modulator which is fabricated on X-cut $LiNbO_3$ substrate by using proton exchange method is described. It is well-known that the proton exchange method is characterized by index change of the single optical modulator. As a results, it is found that the single optical waveguide varied widely with controlling diffusion process. The diffusion process was used to optimize the fabrication of the single optical modulator. On the other hand, the process was used to provide another performance improvement and it reduced the fabrication process.

• 소성∙가공
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• 제13권2호
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• pp.148-153
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• 2004

Finite element analysis of open die forging process to make rectangular billet has been performed in this study. Three dimensional rigid-plastic finite element method was used to analyze the effects of process variables, forging pass design and die configurations on the void closure phenomena to maximize the internal deformation for better structural homogeneity and center-line consolidation of the rectangular billet. The effect of anvil width ratio, anvil pitch, anvil shape and number of pass has been estimated by the degree of void closure ratio. Although it is difficult to optimize process parameters in the operational environments, favourable process conditions are suggested for better product quality.

• 한국자동차공학회논문집
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• 제8권1호
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• pp.32-39
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• 2000

To optimize the cold start process of a 4-stroke, 8 cylinder Diesel engine, a dynamic simulation model from cranking to idle speed is developed. Physically-based first order starter motor dynamics are used to model the performance of starting process which is very complex. These equations are solved using numerical schemes(Petzold-Gear BDF method) to describe the starting process of diesel engine and to study the effects of starting parameters. The validity of this model is examined by start test. This model can be served as a tool for computer aided control systems design to improve cold improve cold start performance.

• 한국전기전자재료학회논문지
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• 제28권1호
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• pp.21-27
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• 2015

We propose a fabrication process of a 3-electrode type reflective display and ascertain the realized color panel. The first design is proceeded with basis on Ti electrode for fast panel fabrication, easy align process, and high reflection of a white image. To observe the particle movement at the lower electrodes and optimize the space between electrodes, we design the second patterns, from which we establish a fabrication process with the mixing of electronic ink, loading of this ink, electronic ink assembly, driving, and packaging. After aging process, we ascertain a normally driving panel with black, white, and blue color.