• 제목/요약/키워드: Coefficients of Correlation

검색결과 4,586건 처리시간 0.033초

The Interaction Between Accretion from the Interstellar Medium and Accretion from the Evolved Binary Component in Barium Stars

  • Jeong, Yeuncheol;Yushchenko, Alexander V.;Doikov, Dmytry N.
    • Journal of Astronomy and Space Sciences
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    • 제35권1호
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    • pp.1-6
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    • 2018
  • The reanalysis of the previously published abundance pattern of mild barium star HD202109 (${\zeta}$ Cyg) and the chemical compositions of 129 thin disk barium stars facilitated the search for possible correlations of different stellar parameters with second ionization potentials of chemical elements. Results show that three valuable correlations exist in the atmospheres of barium stars. The first is the relationship between relative abundances and second ionization potentials. The second is the age dependence of mean correlation coefficients of relative abundances vs. second ionization potentials, and the third one is the changes in correlation coefficients of relative abundances vs. second ionization potentials as a function of stellar spatial velocities and overabundances of s-process elements. These findings demonstrate the possibility of hydrogen and helium accretion from the interstellar medium on the atmospheres of barium stars.

Wind pressures on a large span canopy roof

  • Rizzo, Fabio;Sepe, Vincenzo;Ricciardelli, Francesco;Avossa, Alberto Maria
    • Wind and Structures
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    • 제30권3호
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    • pp.299-316
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    • 2020
  • Based on wind tunnel tests, this paper investigates the aerodynamic behavior of a large span canopy roof with elliptical plan and hyperbolic paraboloid shape. The statistics of pressure coefficients and the peak factor distributions are calculated for the top and bottom faces of the roof, and the Gaussian or non-Gaussian characteristics of the pressure time-histories in different areas of the roof are discussed. The cross-correlation of pressures at different positions on the roof, and between the top and bottom faces is also investigated. Combination factors are also evaluated to take into account the extreme values of net loads, relevant to the structural design of canopies.

Pitfall in calibration development - "chance correlation + wishful thinking" - an example of pH determination in grass silages

  • Tillmann, Peter;Horst, Hartmut
    • 한국근적외분광분석학회:학술대회논문집
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    • 한국근적외분광분석학회 2001년도 NIR-2001
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    • pp.1275-1275
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    • 2001
  • The pH value of grass silages is one important parameter to determine the quality of the forages. In an attempt to use NIRS spectra taken for other quality parameter of grass silage it has been shown that a good correlation between NIR spectra of the dried forage and pH value of the fresh forage could be determined. Further investigations revealed that the B coefficients of the pH value calibration were almost the same as the B coefficients of the sugar calibration multiplied with -1. And indead the pH value - in the fresh sample material - of the calibration set is strongly correlated with the sugar concentration - in the dried sample material. It is concluded that next to scientific tools in research the scientist and the user of NTRS equippment has to scrutinze his own work. Examples are given. NIRS is a powerfull technique, but pitfalls are present in surplus.

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경기도 성남시, 인천시, 강원도 강릉시, 충북 청원군 강수의 화학적 성분에 관한 비교 연구 (A Comparative Study on the Chemical Compositions of Precipitations in Sungnam City of Kyunggi Province, Inchon City, Kangneung City of Kangwon Province, and Chongwon-gun of Chungbuk Province)

  • 박국태;문경언
    • 한국환경과학회지
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    • 제4권3호
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    • pp.285-294
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    • 1995
  • A comparative study on the chemical compositions of precipitations from February 1993 to April 1993 in Sungnam city of Kyunggi province, Inchon city, Kangneung city of Kangwon province, and Chongwon-gun of Chungbuk province has been performed. The metal cation and anion concentrations were measured by atomic absorption spectrometer and ion liquid chromatography, respectively. pH/Ion meter and direct nesslerization method were used for the concentration measurements of $H^+$ and $NH^{4+}$ ions, respectively. The quantitative orders of the cation and anion average concentrations, correlation coefficients between the ion concentrations, and pH values are used for chemical analysis on the environmental pollution and pollutant sources in the urban, surburban, seaside, and rural areas of the Korean Peninsula.

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Effects of solution, sorbate, and sorbent chemistries on polycyclic aromatic hydrocarbon sorption to hydrated mineral surfaces

  • Yim, Soobin
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2003년도 추계학술발표회
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    • pp.132-135
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    • 2003
  • Solution chemistry, sorbate chemistry, and sorbent chemistry were widely investigated to find important factors that affect PAH sorption on mineral surfaces and to elucidate its microscopic mechanism. The solution chemistry, pH and ionic strength caused measurable change of HOC sorption reaction to minerals. The detectable change of Ka occurred at a pH region crossing the PZC (Point of Zero Charge) of each mineral. The PAH hydrophobicity, one of sorbate chemistry, was observed to have a strong correlation with PAM sorption to mineral. Mineral surface area was not found to be a predominant factor controlling PAH sorption. The mineral type might be more likely to play a crucial role in controlling the PAH sorption behavior. The CEC (Cation Exchange Capacity) of mineral, representing surface charge density, has meaningful correlation with regression slope of sorption coefficients (log $K_{d}$) versus aqueous activity coefficients (log Υ$_{w}$).).).

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Experimental investigation of characteristics of torsional wind loads on rectangular tall buildings

  • Li, Yi;Zhang, J.W.;Li, Q.S.
    • Structural Engineering and Mechanics
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    • 제49권1호
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    • pp.129-145
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    • 2014
  • In order to investigate the characteristics of torsional wind loads on rectangular tall buildings, five models with different rectangular cross-sections were tested in a boundary wind tunnel. Based on the test results, the RMS force coefficients, power spectrum densities as well as vertical correlation functions of torsional wind loads were analyzed. Formulas that took the side ratio as parameters were proposed to fit the test results above. Comparisons between the results calculated by the formulas and the wind tunnel measurements were made to verify the reliability of the proposed formulas. An simplified expression to evaluate the dynamic torsional wind loads on rectangular tall buildings in urban terrain is presented on basis of the above formulas and has been proved by a practical project. The simplified expressions as well as the proposed formulas can be applied to estimate wind-induce torsional response on rectangular tall buildings in the frequency domain.

기혼 여성들의 신체만족도와 의복만족도에 관하여 (A study on body cathexis and clothing satisfaction of married women.)

  • 김용숙
    • 대한가정학회지
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    • 제24권3호
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    • pp.1-9
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    • 1986
  • The purpose of this study was to measure the body cathexis and clothing satisfaction sccording to the level of age, job, and total monthly income and to investigate the relationship between body cathexis and clothing satisfaction of married women. 43 items of body parts and body functions were selected to measure body cathexis from Secord and jourard body Cathexis scale. A nd 56 items of Mclean's Clothing Satisfac tion scale were used for clothing satisfaction. The questionnaires were administered to 384 mothers in Jeonbug province. 3-way ANOVA and Newman-Keuls test were used for group difference. Pearson's Correlation Coefficients, Partial Correlation Coefficients, Standard Deviation, and Mean were calculated. RESULTS : 1. Body cathexis of married women showed asignificant difference according to age. 2. Clothing satisfaction of married women showed a significant difference to the interaction of age, job, and total monthly income. The elder and higher income group without job had the highest clothing satisfaction scores than any other group. 3. Positive correlations were found among body cathexis, clothing satisfaction, and 6 subscales of clothing satisfaction.

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농촌유역 소하천에 대한 수질모형의 적용 (An Application of Water quality model for a Stream in Rural Watersheds)

  • 박영진;권순국
    • 한국농공학회:학술대회논문집
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    • 한국농공학회 2002년도 학술발표회 발표논문집
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    • pp.361-364
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    • 2002
  • The WASP model was applied to Bokha stream with 8.4km of its main stem located in Ichon-gun, Kyonggi province in Korea. The stream was divided into 26 segments with each of 400m length, and 5 segments were embraced boundaries of its tributaries. The parameters of the model were calibrated by the trial and error method to minimize differences between observed and simulated concentration of water quality constituents. The correlation coefficients for DO, $NO_3-N,\;PO_4-P$ and organic P showed high values providing the ability of simulation. The correlation coefficients for BOD and $NH_3-N$ showed low values in both calibration and verification test.

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선수동요 동유체마력 추정을 위한 시운전 (A Study on Sea Trial Test Scenario for Estimation of Hydrodynamic Rotary Derivatives)

  • 윤현규
    • 대한조선학회논문집
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    • 제43권1호
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    • pp.50-58
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    • 2006
  • Free running model tests gives us only maneuvering indices not hydrodynamic derivatives. For this reason, system identification method has been applied to the measured data to identify mathematical model describing hydrodynamic force. However It is difficult to obtain complete set of maneuvering derivatives because of strong correlation of sway velocity and yaw rate. Therefore, in this paper, we assumed that sway velocity related coefficients would be obtained by oblique towing test. and then proposed new procedure to estimate yaw related coefficients. To do this, correlation and regression analyses were carried out to establish modified model and estimate maneuvering derivatives. Also D-optimal rudder input scenario was found based on the modified model and confirmed the validity of its sufficient richness as a input scenario.

Wind pressure characteristics for a double tower high-rise structure in a group of buildings

  • Tse, K.T.;Wang, D.Y.;Zhou, Y.
    • Wind and Structures
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    • 제16권5호
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    • pp.491-515
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    • 2013
  • Wind pressure characteristics on a double tower high-rise structure, which is disturbed by surrounding buildings, were investigated using large eddy simulation (LES) and 1:300 scale wind tunnel experiments. The computational simulation technique and wind tunnel experimental technique were described in detail initially. Comparisons of computational results with the experimental data have subsequently been carried out to validate the reliability of LES. Comparisons have been performed in detail for the mean and fluctuating pressure coefficients. Detailed explanations of each comparison were given in the paper. To study further on the pressure coefficients on the building surfaces, parametric studies on shape coefficient and spatial correlation were performed and investigated. The numerical and experimental results presented in this paper advance understanding on wind field around buildings and the application of LES and wind tunnel tests.