• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.3
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• pp.406-412
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• 2010

In this paper, we formally define the problem of maximizing the coverage of sensor deployment, which is the optimization problem appeared in real-world sensor deployment, and analyze the properties of its solution space. To solve the problem, we proposed novel genetic algorithms, and we could show their superiority through experiments. When applying genetic algorithms to maximum coverage sensor deployment, the most important issue is how we evaluate the given sensor deployment efficiently. We could resolve the difficulty by using Monte Carlo method. By regulating the number of generated samples in the Monte Carlo evaluation of genetic algorithms, we could also reduce the computing time significantly without loss of solution quality.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.8-12
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• 2015

Non-esterified bio-diesel fuel saves cost by no esterified process and its performance was more similar to diesel oil than esterified bio-diesel fuel when the fuel blended 95% diesel oil and 5% it was used on diesel engine with electronic control system. A performance optimization is necessary for application of non-esterified bio-diesel fuel blended with diesel oil 95% on the latest diesel engine. In this study, test using fractional factorial design was accomplished at 25% and 50% partial load in order to evaluate influence of controllable 6 factors on responses such as specific fuel consumption, nitrogen oxides and coefficiency of variation of indicated mean effective pressure as basic experiment for performance optimization of this fuel. It is cleared that the injection timing and common rail pressure of 6 factors are mainly effective and its effect level is different according to load.

• Communications for Statistical Applications and Methods
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• v.15 no.2
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• pp.235-244
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• 2008

Balanced arrays which are generalized orthogonal arrays, introduced by Chakravarti (1956) can be used to construct the fractional factorial designs. Especially for 2-level factorials, balanced arrays with strength 4 are identical to the resolution-V fractional designs. In this paper criteria for evaluation the degree of the orthogonality of balanced arrays of 2-levels with strength 4 are developed and some application methods of the suggested criteria are discussed. As a result, in this paper, we introduce the constructing methods of near orthogonal saturated balanced resolution-V fractional 2-level factorial designs.

• Proceedings of the Korean Statistical Society Conference
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• 2005.11a
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• pp.5-11
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• 2005

본 연구에서는 최근에 널리 사용되고 있는 R 프로그램을 이용하여 실험계획법 중 요인배치법과 반응표면분석을 구현하였다. 특히 반응표면분석에서 직교계획, 회전계획, 기울기 회전계획을 만족하는 실험계획을 제공함으로써 상업용 프로그램의 미진한 부분을 개선하여 실험선택의 폭을 넓게 하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.74-74
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• 2017

화학물질관리법 시행에 따른 도금기업의 준비 현황 및 실태를 조사하기 위하여 중간보고서에서는 대부분의 업체에서 가장 부담스럽다고 느낀 '유해화학물질 취급시설 배치 설치 관리 기준' 중 실질적으로 가장 어려움을 호소하는 내용부터 설문조사를 실시하여 정리하였고, 최종보고서에서는 한국경영자총협회에서 제안한 "화관법 개선 산업계 의견"을 참고하여 도금업체의 현장과 관련된 부분을 선정하여 실태조사를 실시하였다. 장외영향평가서 및 위해관리계획서 부문의 경우 도금공장의 시설 결함 및 노후화로 인하여 화학사고가 발생할 가능성이 있더라도 대부분의 현장이 화관법 기준을 충족하기 이전에 시설 허가를 받을 때 건축법이나 소방법 등 여러 규제사항을 통과하여 인 허가를 받은 사업장이고 또한 정기검사를 실시함으로써 안전에 대해서는 일차적으로 보장을 받은 상태라고 볼 수 있다. 실제로 설문조사에서 화학사고를 경험과 관련하여 94% 이상이 "없다"라고 응답하였으므로 약품에 의한 화학사고의 개연성은 거의 없는 것으로 나타났다.

• Transactions of the KSME C: Technology and Education
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• v.2 no.2
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• pp.113-124
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• 2014

In developing an aircraft, configuration determination and requirement proofing depend on flight test results. Since the flight tests require much time and high cost, systematic flight test planning and analysis are needed to reduce cost and development time. This paper presents a desirability function approach to present an integrative measure of vibration levels at important positions and suggests a fractional factorial design which is one of the experimental design methods to help perform systematic flight tests. A method to perform flight tests in stages is also suggested to further reduce the number of flight tests.

• Magazine of the Korean Society of Hazard Mitigation
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• v.10 no.2
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• pp.42-50
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• 2010

국내에서 이용객수가 많은 6개 고속철도 역사와 운행 중인 고속열차(KTX)에 심장마비 환자에 대한 응급처치 장비로서 자동제세동기가 2009년에 설치되었다. 이와 관련하여 6개 역사의 역무원 및 고속열차 승무원과 일반대중에게 심폐소생술 및 자동제세동기 사용법과 일반대중 제세동기 사용허용을 교육하는 고속철도 자동제세동기 보급 및 교육사업도 시행되었다. 이를 통해서 국내 응급의료체계가 한 단계 발전하는 계기가 되었으며 국내 고속철도가 심장마비 환자의 응급 대처 능력을 갖추게 되어, 역사 및 고속열차 안에서 심장마비 환자가 발생하더라도 신속한 대응을 할 수 있을 것으로 기대할 수 있겠다. 본 연구는 이러한 역사 및 고속열차 내에서의 응급의료체계 향상을 위한 노력을 자동제세동기 배치를 통하여 알아보며, 이에 따라 다양한 교통편 및 다중이용시설의 사고, 재난 및 응급 대응이 현재까지 해 오던 건축물 안전, 법규 마련 뿐 만 아닌 인명 피해 감소를 위한 응급의료체계라는 매우 중요한 부분이 있음을 이해하고 이에 대한 시스템 개발 및 대처도 안전과 방재 측면에서 같이 다루어져야 함을 본 연구 내용은 강조하고 있다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.4
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• pp.592-603
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• 2014

We developed various recipes of turmeric powder (Curcuma longa L.) added to milk bread and assessed the individual effects of seven ingredients [milk ($X_1$), turmeric powder ($X_2$), bread improver ($X_3$), fresh yeast ($X_4$), butter ($X_5$), sugar ($X_6$), and salt ($X_7$)] as well as the 2-way interaction effects of the ingredients on the sensory characteristics of breads using fractional factorial design method. The center and end points of each component were determined via literature review and multiple test baking. Seven trained sensory test panels evaluated the outside appearance (OA), inside appearance (IA), and flavor & texture (FT) of 38 breads using 46 items of sensory evaluation. Findings are as follows: for the OA, $X_1$ (P<0.05) and $X_4$ (P<0.0001) exhibited significant individual effects, whereas $X_1*X_7$, $X_2*X_5$, $X_3*X_6$, and $X_4*X_6$ indicated significant interaction effects (P<0.05). For the IA, $X_1$ (P<0.0001), $X_4$ (P<0.0001), $X_6$ (P<0.05), $X_2*X_4$ (P<0.05), and $X_3*X_6$ (P<0.01) showed individual and interaction effects, respectively. For the FT, $X_1$ and $X_2$ showed the most significant individual effect (P<0.0001), followed by $X_4$, $X_5$ and $X_6$ (P<0.05) in descending order. $X_4*X_7$ indicated the only significant interaction effect. We computed the magnitudes of the 2-way interaction effects of the ingredients with a distinct emphasis. Model equations predicting the levels of the ingredient effects on the breads were also provided via regression analyses. In summation, $X_4$ appeared to be the most significant component affecting the sensory characteristics based on its individual and 2-way interaction effects. Further, $X_6$, $X_1$, $X_2$, and $X_5$ indicated both individual and interaction effects. $X_3$ and X7 showed only interaction effects. The center point effect appeared to be unequivocal for whole sensory characteristics. Findings of the present study may provide insights into the selection of ingredients to derive an optimal model for turmeric powder-added bread using the response surface method hereafter.

• Journal of the Korean Applied Science and Technology
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• v.37 no.6
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• pp.1738-1751
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• 2020

The skin is divided into three parts: the epidermis, the dermis, and the subcutaneous fat, and the stratum corneum, which is located at the top of the epidermis, acts as a barrier that prevents drug delivery. Nanoemulsions are known to be effective in transdermal delivery of drugs through intercellular lipids because of their unique small particle size. In this study, phase inversion temperature (PIT) nanoemulsion containing α-bisabolol was optimized using response surface methodology (RSM) for effective skin absorption of α-bisabolol. As a preliminary experiment, the 25-2 fractional factorial design method and the 23 full factorial design method were performed. Box-Behnken design was performed based on the results of the factorial design method. The content of surfactant (6.3~12.6%), co-surfactant (5.2~7.8%) and α-bisabolol (0.5~5.0%) were used as factors, and the dependent variable was the particle size of the nanoemulsion. PIT nanoemulsion optimization was performed according to the RSM results, and as a result, the optimal nanoemulsion formulation conditions were predicted to be 10.4% surfactant content, 6.3% co-surfactant content, and 5.0% α-bisabolol content. As a result of the skin absorption test, the final skin absorption rate of the PIT nanoemulsion was 35.11±1.01%, and the final skin absorption rate of the general emulsion as a control was 28.25±1.69%, confirming that the skin absorption rate of the PIT nanoemulsion was better.

• Journal of the Korea Concrete Institute
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• v.20 no.2
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• pp.147-156
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• 2008

In an uniaxial compressive test of a concrete standard specimen (150$\times$300 mm) the crack initiation and extension with the stress increase are the major reason of the failure, which is similar to the breakage of the particle bonding in the simulation by using particle bonded model, especially particle flow code in 3 dimensions (PFC3D) developed by Itasca Consulting Group Inc. That is the main motive to study the possibility of an uniaxial compressive strength test simulation. It is important to investigate the relationship between the micro-parameters and the macro-properties because the 3-dimensional particle bonded model uses the spherical particles to analyze the physical phenomena. Contact bonded model used herein has eight micro-parameters and there are five macro-properties; Young's modulus, Poisson's ratio, uniaxial compressive strength and the crack initiation stress and the ratio concerning the crack propagation with the stress. To simulate the compressive test we made quantitative relationships between the micro-parameters and the macro-properties by using the fractional factorial design and various sensitivity analyses including regression analysis, which result in the good agreement with the previous studies. Also, the stress-stain curve and the crack distribution over the specimen given by PFC3D showed the mechanical behavior of the concrete standard specimen under the uniaxial compression. It is concluded that the particle bonded model can be a good tool for the analyzing the mechanical behavior of concrete under the uniaxial compressive load.