• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.4
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• pp.67-73
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• 2014

The dry sliding wear behavior of graphite that is used as the sealing material to cut off hot gas was evaluated as a function of applied load, sliding speed and temperature. The reciprocating wear tests were carried out at room temperature and elevated temperatures. An attempt has been made to develop a mathematical model by response surface methodology and an analysis of variance technique was applied to confirm the validity of the developed model. Also, the wear mechanism was compared through the observation of the worn surface by SEM analysis.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.559-564
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• 2017

In this study, the optimization process was carried out by using the central composite model of the response surface methodology in waste cooking oil based biodiesel production process. The acid value, reaction time, reaction temperature, methanol/oil molar ratio, and catalyst amount were selected process variables. The response was evaluated by measuring the FAME content (more than 96.5%) and kinematic viscosity (1.9~5.5 cSt). Through basic experiments, the range of optimum operation variables for the central composite model, such as reaction time, reaction temperature and methanol/oil molar ratio, were set as between 45 and 60 min, between 50 and $60^{\circ}C$, and between 8 and 12, respectively. The optimum operation variables, such as biodiesel production reaction time, temperature, and methanol/oil molar ratio deduced from the central composite model were 55.2 min, $57.5^{\circ}C$, and 10, respectively. With those conditions the results deduced from modeling were as followings: the predicted FAME content of the biodiesel and the kinematic viscosity of 97.5% and 2.40 cSt, respectively. We obtained experimental results with deduced operating variables mentioned above as followings: the FAME content and kinematic viscosity of 97.7% and 2.41 cSt, respectively. Error rates for the FAME content and kinematic viscosity were 0.23 and 0.29%, respectively. Therefore, the low error rate could be obtained when the central composite model among surface reaction methods was applied to the optimized production process of waste cooking oil raw material biodiesel.

• Current Research on Agriculture and Life Sciences
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• v.14
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• pp.101-110
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• 1996

Using response surface methodology(RSM), the various conditions(agitation speed, air flow, glucose concentration) in jar fermentor culture were investigated to find the optimum conditions for maximum enzyme production. Central-composite-design was used to control the variable constant in the experiment. The glucose isomerase production of Steptomyces chibaensis J-59 was mostly affected by the air flow rate and glucose concentration. The estimated optimum conditions were as follows: 1% birchwood xylan, 1.5% CSL, 0.1% $MgSO_4{\cdot}7H_2O$, 0.012% $CoCl_2{\cdot}6H_2O$, pH 7.0; air flow, 2.2vvm; agitation speed, 587rpm; glucose concentration, 0.586%. Experimental values(7.43GIU/ml) for the enzyme production obtained from the given optimum conditions had a almost resemblane to response values(7.67GIU/ml) predicted by the RSM. The jar fermentor culture by the RSM produced xylose isomerase about 2.7 times as much as the baffled flask culture.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.45-50
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• 2012

This paper on analysis of roundness error after boring turning of Al-6061 materials with CNC lathe. Experiment applying turning parameters is based on experimental design method. A design and analysis of experiments is conducted to study the effects of these parameters on the roundness error using the S/N ratio and analysis of ANOVA. Multiple linear regression analysis is applied to compare experimental with predicted data in consideration of roundness error. To fixation pressure and the opening which are a turning parameter, the cutting depth and feed speed respected the objective attainment of dissertation and to be applied the result they investigated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.1
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• pp.107-114
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• 2011

In this study, a correlation between the roughness of nanoscale lapping surface and its laser scattering pattern has been identified experimentally. The characteristics of laser scattering on a reflected surface are investigated, and a laser scattering mechanism is newly designed by adopting the dark-field method. Laser scattering patterns resulting from nanoscale lapping shape are in the shape of crossed irregular lattice. In addition, optimum laser scattering images are obtained by the design of experiment, and the roughness of nanoscale lapping surface is estimated using regression analysis certain useful features of the laser scattering patterns. The results of fifty experiments on three types of nanoscale lapping surfaces show that the roughness of nanoscale lapping surfaces can be accurately estimated by the proposed mathematical modeling method.

• The Korean Journal of Food And Nutrition
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• v.20 no.1
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• pp.1-8
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• 2007

Tortillas were prepared using rice and wheat flour. The experimental design incorporated thee independent variables(rice, wheat flour and moisture content) producing 14 samples of different proportions of each variable for each tortilla. The following were analysed using Design Expert 6 to unveil the influences of these variables on tensile strength and color(L, a, b). Results indicated that tensile strength increased with increasing rice and wheat flour content, however, decreased with increasing moisture content. Lighteness(L), of the tortilla increased with increased rice content whereas yellowness(b) increased with increased wheat flour content. The model suggests that tensile strength and color(L, a, b) in tortillas are highly correlated(SD Comment - give correlation coefficient and p-value). As well, the numerical optimization method suggests that the ratio of wheat flour to rice flour to moisture content which maximizes the three responses(tensile strenth, L and b) is 18.26 : 33.92 : 39.24%, 28.15 : 25.77 : 37.50%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.885-895
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• 2004

Generally, automatic design is carried out with computer simulation and the simulation models are established by investigating the correlations between the simulation and real experiments. Therefore, the experiment results are utilized as complimentary data although they are considered to be precise. Orthogonal arrays have been adopted for discrete design. A method is proposed to directly exploit the experiment results in the design process with orthogonal arrays. Experiments are allocated to some rows of an orthogonal array and computer simulations are allocated to the others. A rule for the allocation is found to keep the orthogonality. Error analysis of the design results is performed. Mathematical examples are made to verify the validity of the proposed method. Error models are defined with the examples and the design solutions from the examples are discussed.

• The Korean Journal of Applied Statistics
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• v.12 no.1
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• pp.241-251
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• 1999

최근 약학계에서 동일한 활성 성분을 가지면서 용량만이 다른 제제의 개발이 증가되고 여러 개의 제제에 대한 생물학적 동등성 시험의 필요성이 대두됨에 따라, 중앙약심은 한 회사에서 개발된 제품으로서 동일한 활성 성분을 함유하고 용량만이 다른 두 가지 시험약에 대하에 동시에 시험을 행할 경우에 한하여 $3\times3$ 라틴방격법에 의한 생물학적 동등성 시험에 인정하기로 하였다. 이를 계기로 이영주 등(1998)은 온덴세트론 제제에 대한 생물학적 동등성 실험에서 $3\times3$ 라틴방격법을 적용하고 그 기준을 제시하고자 하였다. 본 논문에서는 이용주 등(1998)에 의해 제시된 기준에 대하여 통계적으로 재 고찰하고, 지존의 $2\times2$ 라틴방격법에 비해 상대적으로 길어진 총실험시간으로 인한 높은 결측치의 발생 가능성을 보완할 수 있는 3$\times$2 균형불완비블록계획법을 제시하고 분석방법과 적합성을 논의한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.6
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• pp.677-682
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• 2011

In this study, a simulation model developed for a hydraulic breaker is verified through comparison of simulation results to the experimental results. For performance optimization, the design parameters are selected based on the physical parameters of the equipment for ease of modification. Also a factorial experiment and regression analysis were conducted to observe the effect of each parameter on the performance of the hydraulic breaker. As a result, a method for optimizing the performance of a hydraulic breaker is proposed.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.405-410
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• 2008

세계적으로 세계측지좌표계의 도입이 확대됨에 따라 우리나라도 2001년 측량법의 개정을 통해 현재의 지리정보 좌표계변환을 위한 노력을 시행하고 있다. 이러한 측면에서 본 연구에서는 세계측지좌표계 변환방법론, 변환사례 등을 검토 후 한국토지정보시스템 데이터를 대상으로 시범지역을 선정하여 변환실험을 실시하였다. 그 결과 변환 후의 데이터는 국가GIS활용 및 업무지원을 위한 참조적 데이터로서 충분히 이용이 가능한 수준으로 도출되었다. 하지만 한국토지정보시스템 데이터의 세계측지좌표계로의 변환을 위해서는 각 지역별 변환계수를 산정할 필요가 있으며, 지적데이터가 가지고 있는 다양한 원점을 통일원점으로 변환되어야 할 것으로 판단된다. 또한 마지막으로, 기존의 지적데이터가 가지는 다양한 문제점을 그대로 내포하는 수준으로 변환되었다. 따라서 한국토지정보시스템의 세계측지좌표계 변환을 위해서는 본 연구의 결과를 기초로 하여, 더 많은 대상지역에 대한 변환을 통해 오차와 오류의 유형별 원인 분석 후 한국토지정보시스템의 세계측지좌표계 변환의 체계적이고 계획적인 전략을 수립할 필요가 있다.