• 태양에너지
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• 제19권2호
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• pp.45-56
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• 1999

The performance of vertical and horizontal tubes with extended surface of rectangular and triangular cross section was investigated theoretically for boiling heat transfer. A simple method for numerical program assuming one-dimensional heat flow was used to predict the performance of these extended surface tubes. The object of this study was to predict the effects of the height, thickness, numbers and, clearance of the extended surface on boiling heat transfer. The results showed that extended surfaces are quite effective as compared to plane surfaces especially near the bum-out point and to promote heat flux in boiling heat transfer.

• Journal of applied mathematics & informatics
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• 제4권1호
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• pp.211-222
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• 1997

In this paper we present a probabilistic approach for the estimation of realistic error bounds appearing in the execution of basic algebraic floating point operations. Experimental results are carried out for the extended product the extended sum the inner product of random normalised numbers the product of random normalised ma-trices and the solution of lower triangular systems The ordinary and probabilistic bounds are calculated for all the above processes and gen-erally in all the executed examples the probabilistic bounds are much more realistic.

• 산업공학
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• 제9권1호
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• pp.53-62
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• 1996

The Delphi method is widely used for long and middle range forecasting in management science. It is a method by which the subjective data of experts are made to converge using statistical analysis. The Fuzzy Delphi Method(F.D.M.), anew application of the Delphi method using Triangular Fuzzy Numbers(T.F.N.), can help to predict the uncertainty, synthesize the opinion and calculation of those assumed dissemblance index and fuzzy distance. Furthermore, the programming of the F.D.M. process to feed paper and data back to experts can make them more accurately predict the various information.

• 한국수학사학회지
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• 제18권2호
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• pp.43-54
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• 2005

수학사의 교수학적 의미를 살펴보고 수학 교육과정상 수학사의 연계 가능성을 분석하면서 초등학교 교수학적 현상에 적용해 본 사례들을 통해 그 가능성을 논하고자 한다. 이를 통하여 수학 교육학적 입장에서 교실 현장에 나가기 전 예비교사들의 수학사적 연계에 대한 교수경험의 중요성과 교실현장 학생들의 학습경험의 중요성을 수학 교수학적 입장에서 입증할 수 있는 기초 자료를 제공할 것이다.

• 한국안전학회지
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• 제20권1호
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• pp.126-132
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• 2005

The purpose of this study is to propose a method to evaluate task complexity using CIFs(Complexity Influencing Factors). We developed a method that CIFs can be used in the evaluation of task complexity using fuzzy linguistic approach. That is, a fuzzy linguistic multi-criteria method to assess task complexity in a specific task situation was proposed. The CIFs luting was assessed in linguistic terms, which are described by fuzzy numbers with triangular and trapezoidal membership function. A fuzzy weighted average algorithm, based on the extension principle, was employed to aggregate these fuzzy numbers. Finally, the method was validated by experimental approach. In the result, it was validated that TCIM(Tink Complexity Index Method) is an efficient method to evaluate task complexity because the correlation coefficient between task performance time and TCI(Task Complexity Index) was 0.699.

• 디지털융복합연구
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• 제15권4호
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• pp.461-468
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• 2017

현재 제공되고 있는 모바일 게임 추천 시스템들은 실제 사용자가 선호하는 게임에 대한 패턴을 추천하는지, 아니면 단순히 관심 정도의 패턴을 추천하는지 알 수 없어 사용자의 주관적인 선호도를 직접적으로 알 수 없다는 문제점이 있다. 이를 해결하기 위하여 사용자들의 주관적인 선호도를 직접적으로 반영한 계층적 분석 방법(Analytic Hierarchy Process, AHP) 기반 모바일 게임 추천 시스템을 개발하였지만, 사용자들이 선호하는 항목에 대한 척도가 같다고 할지라도 선호하는 정도까지 동일하다고 볼 수 없다는 문제가 발생하였다. 본 연구에서는 이와 같은 문제점을 해결하기 위해 Fuzzy-AHP 기법의 삼각 퍼지 수(Triangular Fuzzy Numbers)와 베이지안 네트워크에서 평가 항목의 독립성을 적용한 모바일 게임 추천 시스템을 구현하였다. 그 결과 본 연구에서 제안한 추천 시스템이 기존의 시스템과 비교하여 볼 때 추천 결과의 정확도 및 사용자의 만족도가 가장 높은 것을 확인할 수 있었다.

• International Journal of CAD/CAM
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• 제4권1호
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• pp.33-45
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• 2004

In this work, a rational procedure has been formulated for the selection of points approximating slice contours cut in LOM (Laminated Object manufacturing) with first order approximation. It is suggested that the number of points representing a slice contour can be 'minimised' or 'optmised' by equating the horizontal chordal deviation (HCD) to the user-defined surface form tolerance. It has been shown that such optimization leads to substantial reduction in slice height calculations and NC codes file size for cutting out the slices. Due to optimization, the number of contour points varies from layer to layer, so that points on successive layer contours have to be matched by four sided ruled surface patches and triangular patches. The technological problems associated with the cutting out of triangular patches have been addressed. A robust algorithm has been developed for the determination of slice height for optimum and arbitrary numbers of contour points with different strategies for error calculations. It has been shown that optimisation may even lead to detection and appropriate representation of elusive surface features. An index of optimisation has been defined and calculations of the same have been tabulated.

• Journal of Advanced Marine Engineering and Technology
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• 제25권3호
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• pp.552-562
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• 2001

Measurement of average of heat transfer and friction coefficients were obtained with air flowing through electrically heated ducts having square, rectangular(aspect ration, 5), and triangular cross section for range of surface temperature from $540^{\circ}$to $1780^{\circ}$ R and Reynolds number from 1000 to 330,000. The results indicates that the effect of heat flux on correlations of the average heat transfer and friction coefficients is similar to that obtained for circular tubes in previous investigation and was nearly eliminated by evaluating the physical properties and density of the air a film temperature halfway between the average surface and fluid bulk temperatures, With the Nusselt and Reynolds numbers on the hydraulic diameter of the ducts, the data for the noncircular ducts could be represented by the same equations obtained in the previous investigation for circular tubes. Correlation of the average difference between the surface corner and midwall temperatures for the square duct was in agreement with predicted values from a previous analysis. However, for the rectangular and triangular ducts, the measured corner temperature was greater by approximately 20 and 35 percent, respectively, than the values predicted by analysis.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.419-422
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• 2003

To improve the recognition accuracy of a developed artificial odor discrimination system for three mixture fragrance recognition, Fuzzy Similarity based Self-Organized Network inspired by Immune Algorithm (F-SONIA) is proposed. Minimum, average, and maximum values of fragrance data acquisitions are used to form triangular fuzzy numbers. Then the fuzzy similarity treasure is used to define the relationship between fragrance inputs and connection strengths of hidden units. The fuzzy similarity is defined as the maximum value of the intersection region between triangular fuzzy set of input vectors and the connection strengths of hidden units. In experiments, performances of the proposed method is compared with the conventional Self-Organized Network inspired by Immune Algorithm (SONIA), and the Fuzzy Learning Vector Quantization (FLVQ). Experiments show that F-SONIA improves recognition accuracy of SONIA by 3-9％. Comparing to the previously developed artificial odor discrimination system that used FLVQ as pattern classifier, the recognition accuracy is increased by 14-25％.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2005년도 추계학술대회지
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• pp.159-163
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• 2005

채널 내부의 비정상 흐름을 규명하기 위하여 실제 사용 중인 판형 열교환기 모델을 대상으로 가시화 실험과 입자영상유속계(PIV)를 사용한 계측을 수행하였다. 실험은 기복을 가지고 있는 채널의 높이와 내부유동의 부분 평균속도벡터에 따른 7가지 종류의 레이놀즈수를 적용하였고, 순간속도벡터분포와 유동특성을 고찰하였다. 실험에서 삼각형상 그루브 채널은 하부 채널과 채널 흐름에 의해서 받고 있는 전단응력의 그루브 흐름과의 관계에서 복합적인 흐름의 형태로 나타났다. 삼각형상 그루브와 채널 사이의 경계인 전단혼합층은 채널에서 난류강도가 상승하는 주흐름에 영향을 미쳤다.