• 대한기계학회논문집B
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• 제27권1호
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• pp.69-75
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• 2003

In this study, his technique was applied to a GDI spray in order to investigate the mixture distribution. In addition, the homogeneity degree and diffusion effect according to ambient temperature in the high pressure chamber were analyzed by using an entropy analysis method. From this experiment, we could find that entropy analysis is very effective method for the analysis of mixture formation, and the entropy values increase with the progress of uniformity in diffusion Process. we tried to provide the fundamental data for parameter which effects on the spray macroscopic characteristics with mixture ratio of diesel and gasoline. In addition, the mixture formation was analyzed by using entropy analysis. The entropy analysis is based on the concept of statistical entropy, and it identifies the degree of homogeneity in the fuel concentration. From the entropy analysis results we could find that the direct diffusion phenomena is a dominant factor in the formation of a homogeneous mixture at downstream of GDI spray especially in vaporizing conditions. As to increasing ambient temperature and increasing gasoline rate, the entropy intensity using the statistic thermodynamics method is increased because evaporation rate is higher gasoline than diesel.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제9권1호
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• pp.4-9
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• 2009

Fuzzy entropy is designed for non convex fuzzy membership function using well known Hamming distance measure. Design procedure of convex fuzzy membership function is represented through distance measure, furthermore characteristic analysis for non convex function are also illustrated. Proof of proposed fuzzy entropy is discussed, and entropy computation is illustrated.

• The Korean Journal of Ecology
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• 제10권2호
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• pp.91-107
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• 1987

This study is concerned with some methods and applications, used as a basis on information and entropy analysis of vegetation data. These methods are adopted for the evaluating the effect of sampling intensity on information, which repersnets the departure of observed variable from standard component. Classes on the data matrix are caluculated by using marginal dispersion array for rank and weighting information program. Finally the information and entropy are computed by applying seven options. On the application of vegetation studies, two models for cluster analysis and analysis of concentration are explained in detail. Cluster analysis is based on use of equivocation information and Rajski's metrics. The analysis of concentration utilizes coherence coefficience being transformed values, which has been adjusted from blocks and entropy values. The relationship btween three begetation clusters and four stands of Naejangsan data is highly significant in 79% of total variance. Cluster A relatively tends to prefer north side, and cluster C south side.

• 한국자동차공학회논문집
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• 제10권6호
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• pp.44-50
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• 2002

The spray characteristics of GDI(Gasoline Direct Injection) injector affects on engine efficiency and emission of a GDI engine. Thus, many researchers have investigated the spray characteristics and the mixture formation of GDI injector. In this study, it was tried to provide the fundamental data for GDl injector design which effects on the spray macroscopic characteristics such as penetration and spray angle. In addition, the mixture formation analyzed by using entropy analysis. The entropy analysis is based on the concept of statistical entropy, and it identifies the degree of homogeneity in the fuel concentration. The results show that as injection pressure increases but as ambient pressure increases, spray penetration decreases and spray angle doesn't affected by increasing injection pressure and ambient temperature. From the entropy analysis results, we could find that the direct diffusion phenomena is a dominant factor in the formation of a homogeneous mixture at downstream of GDI spray especially in vaporizing conditions.

• 한국정보통신학회논문지
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• 제22권9호
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• pp.1153-1158
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• 2018

다양한 온라인 고객 평가 및 소셜 미디어 정보는 고객의 의사결정에 영향을 미치기 때문에 기업에게 매우 중요한 정보 출처라고 할 수 있다. 설문 조사를 통해 고객의 다양한 요구와 불만 사항을 파악하는 데는 많은 비용과 시간적인 제약이 발생하고 있다. 온라인 쇼핑몰의 고객 후기 데이터는 제품에 대한 고객들의 감성을 분석할 수 있는 이상적인 자료를 제공하고 있다. 본 연구에서는 삼성과 애플 스마폰에 대한 감성분석을 위해 아마존 쇼핑몰로부터 고객 리뷰 데이터를 수집하였다. 선행 연구에서 대표적인 감성분석 기법으로 사용된 5가지 분류 알고리즘을 적용하였다. 5가지 분류알고리즘은 support vector machines, bagging, random forest, classification or regression tree, maximum entropy 등이다. 본 연구에서는 분류 알고리즘의 수행도를 종합적으로 평가할 수 있는 entropy score를 제안하였다. Entropy score를 이용하여 5가지 알고리즘을 평가한 결과에 따르면 support vector machines 알고리즘의 entropy score가 가장 높은 것으로 분석되었다.

• Communications for Statistical Applications and Methods
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• 제19권6호
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• pp.837-847
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• 2012

Inverse Gaussian distribution is widely used in applications to analyze and model right-skewed data. To assess the appropriateness of the distribution prior to data analysis, Mudholkar and Tian (2002) proposed an entropy-based test of fit. The test is based on the entropy power fraction(EPF) index suggested by Gokhale (1983). The simulation results report that the power of the entropy-based test is superior compared to other goodness-of-fit tests; however, this observation is based on the small-scale simulation results on the standard exponential, Weibull W(1; 2) and lognormal LN(0:5; 1) distributions. A large-scale simulation should be performed against various alternative distributions to evaluate the power of the entropy-based test; however, the use of a theoretical method is more effective to investigate the powers. In this paper, utilizing the information discrimination(ID) index defined by Ehsan et al. (1995) as a mathematical tool, we scrutinize the power of the entropy-based test. The selected alternative distributions are the gamma, Weibull and lognormal distributions, which are widely used in data analysis as an alternative to inverse Gaussian distribution. The study results are provided and an illustrative example is analyzed.

• Communications for Statistical Applications and Methods
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• 제12권1호
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• pp.125-137
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• 2005

Many discriminant analysis models for binary data have been used in real applications, but none of the classification models dominates in all varying circumstances(Asparoukhov & Krzanowski(2001)). Lee and Hwang (2003) proposed a new classification model by using multinomial distribution with the maximum entropy estimation method. The model showed some promising results in case of small number of variables, but its performance was not satisfactory for large number of variables. This paper explores to use the iterative cross entropy minimization estimation method in replace of the maximum entropy estimation. Simulation experiments show that this method can compete with other well known existing classification models.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1699-1710
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• 2001

The characteristics of methanol and methanol blended (M85) sprays were investigated under atmospheric conditions at various temperature, ranging from on-vaporizing to vaporizing ambient conditions (298∼353 K). From laser scattering images, the macroscopic characteristics of the spray, such as the spray tip penetration and the spray angle, were determined. Entropy concept was introduced to represent homogeneity and PIV analysis was adopted to determine the fluid dynamic information at each location of the spray. The correlation between entropy and vorticity strength enabled us to find their relations. The effect of ambient composition, mainly of viscous effect as affected by CO$_2$levels, was investigated using PIV and entropy analysis. Spray width and entropy value were found to tend to decrease at increased CO$_2$levels.

• 대한화학회지
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• 제53권1호
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• pp.62-72
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• 2009

이 연구에서는 우리나라 대학에서 주로 채택하는 일반화학 교재를 포함한 미국에서 출판된 총 12 종의 일반화학 교재들에 있는 ‘엔트로피’의 정의와 설명방법을 분석하였다. 분석은 두 부분으로 구성된다. 하나는 같은 저자들이 저술한 교재의 판 별 변화를 살펴본 통시적 분석이며 다른 부분은 세 가지 영역 (엔 트로피 정의와 설명방법에 쓰인 무질서, 엔트로피 정의와 설명방법에 Microstates의 수 도입, 통계학적 엔 트로피와 열역학적 엔트로피를 배울 때의 오개념 가능성)으로 살펴본 내용적 분석이다. 연구 결과, 엔트로 피를 무질서의 정도라고 정의하는 것은 지양되었고, Microstates의 수를 이용한 설명 방법으로 대체 되었 다. 또한, 두 가지 다른 엔트로피가 존재한다고 믿는 오개념의 발생 가능성에 대한 주의점을 기술한 교재도 발견되었다. 엔트로피 설명방법의 이러한 변화를 새로운 교육과정에 반영하고 교사들을 재교육하는 것은 우리나라 화학교육의 발전에 중요한 일이다.

• 한국지능시스템학회:학술대회논문집
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• 한국지능시스템학회 2008년도 춘계학술대회 학술발표회 논문집
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• pp.21-22
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• 2008

Fuzzy entropy is designed for non-convex fuzzy membership function using well known Hamming distance measure. Design procedure of convex fuzzy membership function is represented through distance measure, furthermore characteristic analysis for non-convex function are also illustrated. Proof of proposed fuzzy entropy is discussed, and entropy computation is illustrated.