• 제목/요약/키워드: center method

검색결과 21,845건 처리시간 0.048초

A parameter calibration method for PFC simulation: Development and a case study of limestone

  • Xu, Z.H.;Wang, W.Y.;Lin, P.;Xiong, Y.;Liu, Z.Y.;He, S.J.
    • Geomechanics and Engineering
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    • 제22권1호
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    • pp.97-108
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    • 2020
  • The time-consuming and less objectivity are the main problems of conventional micromechanical parameters calibration method of Particle Flow Code simulations. Thus this study aims to address these two limitation of the conventional "trial-and-error" method. A new calibration method for the linear parallel bond model (CM-LPBM) is proposed. First, numerical simulations are conducted based on the results of the uniaxial compression tests on limestone. The macroscopic response of the numerical model agrees well with the results of the uniaxial compression tests. To reduce the number of the independent micromechanical parameters, numerical simulations are then carried out. Based on the results of the orthogonal experiments and the multi-factor variance analysis, main micromechanical parameters affecting the macro parameters of rocks are proposed. The macro-micro parameter functions are ultimately established using multiple linear regression, and the iteration correction formulas of the micromechanical parameters are obtained. To further verify the validity of the proposed method, a case study is carried out. The error between the macro mechanical response and the numerical results is less than 5%. Hence the calibration method, i.e., the CM-LPBM, is reliable for obtaining the micromechanical parameters quickly and accurately, providing reference for the calibration of micromechanical parameters.

Novel Measurement Method for Evaluating Moving Picture Quality of Display

  • Kim, Jae-Shin;Chong, Jong-Ho;Kim, Sang-Ho;Kim, Gun-Shik;Bae, Jae-Woo;Lee, Seung-Bae;Oh, Jun-Sik
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.1039-1042
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    • 2008
  • We propose a novel method to measure moving picture quality of display. This method simulates human visual system based on CSF (Contrast Sensitivity Function). And it evaluates moving picture quality of display on the image captured by pursuit camera. The results from this method are correlated with human visual perception test very well.

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육두구(Myristica fragrans Houttuyn) 내의 myristicin의 분리 및 HPLC를 이용한 함량분석 방법 밸리데이션 (Isolation and Quantitative Determination Method Validation of myristicin from Myristica fragrans Houttuyn)

  • 김수환;이동호;권수한;임병호;이상훈;민범찬
    • 생약학회지
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    • 제38권1호
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    • pp.19-21
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    • 2007
  • Myristica fragrans has been used for the treatment of stomachache in East Asia. It is very important to determine the amount of myristicin in Myristica fragrans, because excess myristicin causes side effects. In this study, we developed and validated the method for determination contents of myristicin in Myristica fragrans which was purchased from various regions of Korea. The average content of myristicin in Myristica fragrans was 2.10% with the validated HPLC analysis method.

아르키메데스가 《The Method》에서 원뿔의 무게중심을 구한 방식에 대한 하나의 가설 (An Assumption on How Archimedes Found out the Center of Gravity of Cones in 《The Method》)

  • 박선용;홍갑주
    • 한국수학사학회지
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    • 제26권5_6호
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    • pp.371-388
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    • 2013
  • In ${\ll}$The Method${\gg}$, Archimedes presented the famous heuristic technique for calculating areas, volumes and centers of gravity of various plane and solid figures, utilizing the law of the lever. In that treatise, Archimedes used the fact that the center of gravity of a cone lies one-quarter of the way from the center of the base to the vertex, but the proof of this is not extant in his works. This study analyzes the propositions and their relations of ${\ll}$The Method${\gg}$ focusing on the procedural characteristics of the 'method' of Archimedes. According to the result of that analysis, this study discusses the likely approach which was taken for Archimedes to find out the center of gravity of a cone.

INTRODUTION TO AN EFFICIENT IMPLEMENTATION OF THE SUBSTITUTE WAVELET INTENSITY METHOD FOR PANSHARPENING

  • Choi, Myung-Jin;Song, Jeong-Heon;Seo, Du-Chun;Lee, Dong-Han;Lim, Hyo-Suk
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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    • pp.620-624
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    • 2007
  • Recently, Gonzalez-Audicana et al. proposed the substitute wavelet intensity (SWI) method which provided a solution based on the intensity-hue-saturation (IHS) method for the fusing of panchromatic (PAN) and multispectral (MS) images. Although the spectral quality of the fused MS images is enhanced, this method is not efficient enough to quickly merge massive volumes of data from satellite. To overcome this problem, we introduce a new SWI method based on a fast IHS transform to implement efficiently as an alternative procedure. In addition, we show that the method is well applicable for fusing IKONOS PAN with MS images.

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Introduction of a Fast Substitute Wavelet Intensity Method to Pan-sharpening Technique

  • Choi, Myung-Jin;Song, Jeong-Heon;Seo, Du-Chun;Lee, Dong-Han;Lim, Hyo-Suk
    • 대한원격탐사학회지
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    • 제23권5호
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    • pp.347-353
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    • 2007
  • Recently, $Gonz\acute{a}lez-Aud\acute{i}cana$ et al. proposed the substitute wavelet intensity(SWI) method which provided a solution based on the intensity-hue-saturation(IHS) method for the fusing of panchromatic(PAN) and multispectral(MS) images. Although the spectral quality of the fused MS images is enhanced, this method is not efficient enough to quickly merge massive volumes of data from satellite. To overcome this problem, we introduce a new SWI method based on a fast IHS transform to implement efficiently as an alternative procedure. In addition, we show that the method is well applicable for fusing IKONOS PAN with MS images.

A Quantitative Method of Measuring Color Expression Power in Eye shadow

  • Kim, Sangjune;Lee, Jaeuk;Kim, Hyungjin;Kim, Jinjun;Kang, Seh-hun
    • 대한화장품학회지
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    • 제26권1호
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    • pp.233-238
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    • 2000
  • We developed a quantitative method for evaluating CEP(color expression power) in eye shadow. This method enables the cosmetic industry to measure CEP on an interval scales, so it is more accurate and reproducible than previous panel tests. Oil, colorants, Pigments and pearls are major factors affecting CEP in eye shadow formulas. We studied the oil effect on CEP using our unique method so CEP could be improved. We believe this method can be applied to other color cosmetics as well. In conclusion, we expected this method to be useful to formulator who want to improve the color expression power in color cosmetics. Additionally, we hope it will contribute toward developing the experiential know-how about color to scientific knowledge.

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Stability evaluation for the excavation face of shield tunnel across the Yangtze River by multi-factor analysis

  • Xue, Yiguo;Li, Xin;Qiu, Daohong;Ma, Xinmin;Kong, Fanmeng;Qu, Chuanqi;Zhao, Ying
    • Geomechanics and Engineering
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    • 제19권3호
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    • pp.283-293
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    • 2019
  • Evaluating the stability of the excavation face of the cross-river shield tunnel with good accuracy is considered as a nonlinear and multivariable complex issue. Understanding the stability evaluation method of the shield tunnel excavation face is vital to operate and control the shield machine during shield tunneling. Considering the instability mechanism of the excavation face of the cross-river shield and the characteristics of this engineering, seven evaluation indexes of the stability of the excavation face were selected, i.e., the over-span ratio, buried depth of the tunnel, groundwater condition, soil permeability, internal friction angle, soil cohesion and advancing speed. The weight of each evaluation index was obtained by using the analytic hierarchy process and the entropy weight method. The evaluation model of the cross-river shield construction excavation face stability is established based on the idea point method. The feasibility of the evaluation model was verified by the engineering application in a cross-river shield tunnel project in China. Results obtained via the evaluation model are in good agreement with the actual construction situation. The proposed evaluation method is demonstrated as a promising and innovative method for the stability evaluation and safety construction of the cross-river shield tunnel engineerings.

복합구조물의 RCS 저감을 위한 효율적 산란중심 해석에 관한 연구 (A Study on the Effective Scattering Center Analysis for Radar Cross Section Reduction of Complex Structures)

  • 김국현;김진형;조대승
    • 대한조선학회논문집
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    • 제42권4호
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    • pp.421-426
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    • 2005
  • Scattering center extraction schemes for radar cross section reduction of large complex targets, like warships, was developed, which are an 1-D radar image method(range profile), and a direct analysis based on an object precision method. The analysis result of partial dihedral model shows that the presented direct analysis method is more efficient than the 1-D radar image method for scattering center extraction of interested targets, in terms of radar cross section reduction design, not signal processing. In order to verify the accuracy of the direct analysis method, a scattering center analysis of an naval weapon system was carried out, and the result was coincident with that of another well-known RCS analysis program. Finally, an analysis result of RCS and its scattering center of an 120m class warship-like model presented that the direct analysis method can be an efficient and powerful tools for radar cross section reduction of large complex targets.

용접 연결부의 거동에 관한 연구 (A Study on the Behavior of Welded Connections)

  • 안주옥;윤영만
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1994년도 가을 학술발표회 논문집
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    • pp.145-151
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    • 1994
  • Welded connections have been designed on basis of allowable stresses, wherein the response to loading is assumed to be totally elastic. This is the vector analysis method, which resolves the stresses determined from the direct stress formula and the torsion formula into a vector combination to obtain a solution. It has been known that this method gives conservative answers and typically a very high factor of safety. An analytical method based on the Instantaneous Center of Rotation has been developed which predicts the ultimate strength of an eccentically loaded fillet welded connection. The method of Instantaneous Center of Rotation results in weld resistance capacities greater than the vector analysis method, by recognizing the variation in fillet weld strength with respect to the direction of the applied loading and actual load-deformation response of elemental fillet welds. The procedure of numerical analysis is iterative and complex. The relations between vector analysis method and the method of Instantaneous Center of Rotation on eccentrical distance subjected to variation of load direction are presented in this paper. Considering of the effects on configuration of weld groups, the method of Instantaneous Center of Rotation are provided a more exact results of the numerical analysis.

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