• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.73-74
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• 2012

The elastic modulus of recycled aggregate concrete (RAC) can be evaluated by using composite models with experiment. In this study, Hashin's composite model was adapted to evaluate elastic modulus considering physical properties of recycled coarse aggregate (RCA) that mortar is attached. Elastic modulus testes for cement paste, mortar and recycled coarse aggregate concrete were carried out considering W/C and recycled coarse aggregate content rate. As a result, the elastic modulus of RAC was evaluated comparing with both experiment results and the existing estimation formula. Those can be used for further studies as a preliminary data.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.63-71
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• 2000

In this study a drift prediction model based on fluid dynamics theory is introduced. The essential effects of environmental loads and target characteristics are taken into account from a fluid dynamics point of view. The governing equations of motion are derived from Newton's law of dynamics. In the mathematical formulation only three degrees of freedom(surge, sway, yaw) of the drifting object are assumed and the environmental loads considered are the forces and moments by wind and current. A computer algorithm for this model is implemented to obtain the numerical result in the time domain. The preliminary tests for model verification are conducted and the results are compared with the field experiment data as well as leeway formula suggested from the field test data.

• 한국유기농업학회지
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• 제18권3호
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• pp.291-313
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• 2010

The objective of this paper is to apply choice experiment methods to estimate non-market value of organic farming and its policy implication. A preliminary survey shows that the attributes of organic farming are reduce environmental pollution, bio-diversity improvements, cultural diversity improvements and maintain local community, reduce green-house gas emissions, energy saving, landscape improvements and tax for organic farming improvement policy. Questionnaire was eight different choice sets presented to each respondent. Implicit values of the attributive levels of organic farming have been calculated into tax money costs per house. This paper compared the six feasible scenarios in terms of willingness to pay per year. This study is expected to contribute to government's organic farming policies and quantitative information related to practice of organic farming.

• 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.

• Journal of Advanced Marine Engineering and Technology
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• 제24권6호
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• pp.89-95
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• 2000

To obtain an exact flow loss in piping systems is very important in the face of efficiency anticipation and work control of plant. The object of this study is to get the flow loss through the experiment for sudden expansion and contraction part of circular pipe nozzle. The experiment in this study is performed after getting the flow loss factor for sudden expansion and contraction through preliminary experiments. It is confirmed that the results of this study agreed with the approximated equation of Ikeda and Matsuo. It is proved that flow loss factor ${\zeta}_3$for sudden expansion and contraction part of circular pipe is dependent on $L/D_1$in these experimental conditions.

• 한국생산제조학회지
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• 제21권3호
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• pp.382-386
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• 2012

A femtosecond laser with 775nm central wavelength and 150 fs of temporal pulse width was used for multi layered glass cutting applications. Ultrashort pulse was effectively used for clean glass cutting with $50{\mu}m$ depth and minimum cutting width. Laser beam was split to two stages and focused on the top surfaces of each layer. Ablation threshold of used glass was measured to be $2.59J/cm^2$. In experiments, 200mW laser power and 1mm/s scanning speed was used for preliminary experiment. Air gap was the major defect occurring parameter and laser power was less sensitive to glass cutting in the experiment. The maximum cutting speed was measured to be 60mm/min with 2kHz, however, Maximum 3m/min cutting speed can be achievable with a commercially available laser with 100kHz.

• 한국항공우주학회지
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• 제33권2호
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• pp.75-83
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• 2005

NASA와 독일 DLR의 Gravity Recovery and Climate Experiment (GRACE)는 편대비행을 하는 두 개의 저궤도 위성을 이용하여 지구중력장을 측정하는 연구이다. 주요 관측 장비는 위성 사이의 거리를 측정하기 위한 초단파 거리측정기와 비중력 가속도를 측정하기 위한 정전기 방식의 3축 가속도계이다. 기본설계 및 허용오차 분석 등에 활용하기 위하여 정밀한 관측기 시뮬레이션 모델을 개발하였는데, 본 논문에서는 이러한 모델링 기법과 이를 적용한 궤도 및 중력장 추정기법에 관해 살펴보았다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.102-107
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• 2004

New designed floating breakwater made of Polyethelener with considering the introduction of new material for being harmony with environment and stability of the floater is developed for a marine ranching. Model experiment in order to test its capability is performed for the regular and irregular waves in ocean engineering basin. Good capability to break the incident wave within the 6 second of period and 1 m of height is shown. Breaking efficiency for long period wave is not so good in regular and irregular wave. The results of this study will contribute to the design and construction of the floating breakwater.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.231-236
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• 2007

In this paper, we studied the possibility of non-contact bill counting method using optical fiber sensor instead of traditionally used friction counting method. To implement non-contact counting, we designed and made optical fiber sensor and related parts. optical fiber sensor is made of optical fiber of 1mm diameter, photo diode and laser diode. Based on the conclusion which derived from preliminary experiment, instrument part is designed to make unevenness on the surface of bill paper and to stay parallel with optical fiber section. By analyzing the signal of optical sensor, we made counting program. Experimental instrument is composed of sensor part, instrument part, signal handling part. We checked the possibility of non-contact counting method after implementing experiment by using optical fiber sensor and instrument part.

• Elastomers and Composites
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• 제50권4호
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• pp.251-257
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• 2015

The rubber seal is a part inserted into servo cylinder to keep the air pressure constant. In order for efficient movements of the servo cylinder, the frictional coefficient of the rubber seal needs to be minimized while the sealing is maintained. In this work the friction characteristics of rubber seal specimen are tested on metal plate at various conditions. The experimental conditions include roughness level, applied pressure, lubrication, and rubbing speed. The design of experiment approach is taken to assess the effect of each parameter. The nonlinear frictional response of the rubber is applied to the FEM model simulating the servo cylinder movement. The result demonstrates that precise optimization of the servo cylinder movement must be preceded by preliminary experiments coupled with the theory and FEM model.