• Title/Summary/Keyword: Correlations analysis

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Use of similarity indexes to identify spatial correlations of sodium void reactivity coefficients

  • Jimenez-Carrascosa, Antonio;Garcia-Herranz, Nuria
    • Nuclear Engineering and Technology
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    • v.52 no.11
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    • pp.2442-2451
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    • 2020
  • The safety level of Sodium Fast Reactors is directly related with the sodium void reactivity. A low-void effect design has been proposed within the Horizon2020 ESFR-SMART project thanks to the introduction of a sodium plenum above the active core. In order to assess the impact of this core conception on transient analysis, a map with the spatial distribution of sodium void worth can be computed and fed into a point-kinetics-based transient code. Due to the spatial correlations between neighboring zones, the global effect of voiding two different axial or radial regions is not necessarily the sum of both individual contributions. Neglecting those correlations in the void worth map and consequently in the transient analysis may lead to an unrealistic prediction of the transient sequences. In this work, a method based on sensitivity analysis and similarity assessment is proposed for predicting those correlations. The method proved to be able to establish correlations between axial slices of a sub-assembly and was checked against realistic sodium void propagation patterns.

An Experimental Study of Pressure Drop Correlations for Wire-Wrapped Fuel Assemblies

  • Chun, Moon-Hyun;Seo, Kyong-Won;Park, Seok-Ki;Nam, Ho-Yun
    • Journal of Mechanical Science and Technology
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    • v.15 no.3
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    • pp.403-409
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    • 2001
  • The main objective of the present study is to perform an experimental evaluation of five existing correlations for the subchannel pressure drop analysis of a wire-wrapped fuel assembly. For this purpose, a series of water experiments have been performed using a helical wire-wrapped 19-pin fuel assembly for various test parameters. Four different test sections with different pitch to rod diameter ratios (P/D) and wire lead length to rod diameter ratios (H/D) have been fabricated. A series of pressure drop measurements were made to obtain friction factors for these four test sections. The new data along with existing data are used to evaluate existing correlations. Both the original and the simplified Cheng and Todreas correlations give the best agreement with experimental data for all flow regions.

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PCCS Analysis Model for the Passively Cooled Steel Containment

  • Hwang, Y.D.;Chung, B.D.;Cho, B.H.;Chang, M.H.;Jeong, Ik
    • Nuclear Engineering and Technology
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    • v.30 no.1
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    • pp.26-39
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    • 1998
  • The containment pressure and temperature transient analysis computer code CONTEMPT4/MOD5 is modified to incorporate the passive containment cooling models. The correlations are selected from the existing experimental heat transfer correlations to model the natural and mixed convection in annular space between the containment shell and the shield building. The evaporative heat transfer of the water film on the outer shell of the containment is modeled using the correlations derived from the analogy between the heat and mass transfer. The modified code is applied to the Ap600 containment transient analysis for the model verification and the results are compared to the results of GOTHIC calculation done by Westinghouse. Also, d series of parametric sensitivity studies of heat transfer correlations, water film ratio and delay time of the wet cooling on the containment peak pressure and temperature following LOCA are performed for the containment of 1000MWe passive plant, KP1000.

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Basic Studies on Correlations between Postpartum Edema and Heart Rate Variability (산후부종과 HRV의 연관성에 관한 기초연구)

  • Hwang, Jae-Ho;Yun, Young-Jin
    • The Journal of Korean Obstetrics and Gynecology
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    • v.24 no.4
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    • pp.186-193
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    • 2011
  • Purpose: This study was performed to find correlations between Edema Index and Heart Rate Variability(HRV) conducted in early postpartum period. Methods: 17 postpartum women were participated in this study which was conducted with Inbody 720(Biospace Co. Ltd.) and SA-6000(Medicore Co. Ltd.). Edema Index(Extra Cellular Water/Total Body Water) was calculated after body composition analysis and HRV result(TP, VLF, LF, HF, HF norm, LF norm, LF/HF ratio) was analysed within a week after delivery. Results: There was no significant correlations between Edema Index and HRV results in time domain analysis. also Edema Index and TP, LF, HF, LF/HF ratio have no significant correlations in frequency domain analysis. but only VLF data has significance compared with Edema Index. Conclusions: It can be suggested that VLF results analysed by HRV can be useful reference estimating postpartum edema especially occurs in early postpartum period.

Characteristics of Clay Minerals in Sihwa Area (시화지구 연약점토의 광물학적 특성)

  • 김낙경;박종식;김유신
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.773-780
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    • 2003
  • The characteristics of soft clays is very important for the land development plan. This study is to investigate correlations between the engineering properties and the characteristics of clay minerals of the disturbed clay samples obtained from Sihwa area. This study included X-Ray Diffraction Analysis, X-Ray Fluorescence Spectrometer Analysis, Scanning Electron Microscopy Analysis and Energy Dispersive X-Ray Spectrometer Analysis. The correlations between the clay mineral properties and the laboratory and field testing results were investigated.

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A study on the model of homebound senior's meal satisfaction related to the quality of life

  • Lee, Sun-Mee;Joo, Na-Mi
    • Nutrition Research and Practice
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    • v.6 no.4
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    • pp.357-365
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    • 2012
  • This study was conducted to develop a construct model regarding the daily activities, emotional security provided by food, enjoyment of food, level of satisfaction with delivered food, and the quality of life of homebound seniors who benefitted from meal delivery programs. The data were analyzed by SAS 9.2 and the Structural Equation Model (SEM), which was created by Analysis of Moment Structure (AMOS) 5.0 packages. The reliability of the data was confirmed by an exploratory factor analysis and through a Cronbach's alpha coefficient, and the measurement model proved to be appropriate by a confirmatory factor analysis of the measurement model in conjunction with AMOS. The results of the correlations between all the variables showed significant positive correlations (P < 0.05). The path analysis demonstrated that the daily activities (P < 0.01) and the emotional security created by food (P < 0.05) had positive correlations with the foodservice satisfaction (P < 0.05), while the daily activities (P < 0.05), the sense of emotional security made by food (P < 0.05), and food enjoyment (P < 0.05) also presented significant positive correlations with the quality of life. However, the food service satisfaction was shown to directly, but not significantly, affect the quality of life. This revealed that the current meal delivery programs needed to be improved in several directions.

The analysis of RF dosimetric uncertainties by using statistical method at in-vivo and in-vitro experiments (RF 전자기장 생체 영향 실험에서 통계적 방법을 통한 전자기장 노출 불확실성 분석)

  • Choi, Sung-Ho;Kim, Nam
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2003.11a
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    • pp.74-78
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    • 2003
  • This paper shows the dosimetric uncertainties of electromagnetic field at in-vivo and in-vitro experiments. For more accurate consequences of these researches, we have tried to find out any correlations among output power, power density and specific absorption rate(SAR) with the results of in-vivo, in-vitro tests and SAR reports of cellular phone and PDA. In the case of in-vivo tests, the power density has close statistical correlations with SAR value and in the event of in-vitro tests, the output power has considerable statistical correlations with SAR containing duty factor. On the other hand, we found that both power density and output power don't have any close correlations with SAR. And, we obtained fitted regression form among frequency, power density and SAR containing duty factor through multiple linear regression analysis.

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A Canonical Correlation Analysis of the Relationship between Menu Management Variables and Performance in Contract-Foodservice Operations (위탁 급식 점포의 메뉴 운영 요인과 성과의 연관성에 관한 연구)

  • Park, Ju-Yeon;Kim, Tae-Hee
    • Journal of the East Asian Society of Dietary Life
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    • v.18 no.6
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    • pp.1089-1098
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    • 2008
  • The principal objective of this study was to reveal the relationship between the menu management indicators and menu performance indicators in contract-foodservice operations. Menu indicators differed according to the type of business, type of contract, type of serving, and number of service lines. In accordance with the results of our correlation analysis, we noted significant correlations between menu performance indicators and menu management indicators. The first of these was the correlation between the food cost ration and meal counts, food loss, and the use of prepared vegetables. The second of these was the correlation between food cost per meal and forecasting error, food loss, and inventory turnover. The last of these correlations was the negative correlation between menu CSI(customer satisfaction index) and the use of prepared vegetables. According to the results of our canonical correlation analysis, 2 significant functions were identified. In the first function, we noted significant correlations between meal counts, use of prepared vegetables, food loss, and food cost ratio. Additionally, we noted significant correlations between forecasting error, inventory turnover, food loss, and food cost per meal in the second function. Menu management indicators had no influence on customer satisfaction.

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A Study on Knowledge, Consciousness and Attitude about Middle School Students and Mothers' Environment-Friendly Life Resources Management (중학생 자녀와 어머니의 생활자원관리에 대한 친환경 지식과 의식 및 태도)

  • Im, Hae-Yeon;Park, Sun-Hee
    • Korean Journal of Human Ecology
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    • v.9 no.3
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    • pp.23-36
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    • 2006
  • The present study purposed to examine how the knowledge, consciousness and attitude affect life resources use of the subjects, first-year middle school students and their mothers, and ultimately, to provide basic materials for maximizing the effect of the education consciousness and attitude on environment-friendly life resource management in everyday living. The followings are the results of the analysis of the collected data. First, in the aspects of analysis of valiance in the general home environment factors of this research, there were some significance according to fathers and mothers' educational level, fathers' job, the type of a house about students and mothers' life resources use. Second, knowledge about middle school students' life resources use had negative correlations with attitude. But consciousness had positive correlations with attitude. Knowledge about their mothers' life resources use had negative correlations with attitude, but consciousness had positive correlations with attitude. The results of mothers were similar to those of middle school students. Mothers' consciousness and attitude had positive correlations with middle school students' consciousness and attitude.

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Development of Interactional Information Measuring Technique Using Information Gathering and Utilizing System in Analysis of Correlations between Rural Amenities

  • Lee, Je-Myung;Jung, Nam-Su;Lee, Jeong-Jae
    • Journal of The Korean Society of Agricultural Engineers
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    • v.49 no.3
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    • pp.69-75
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    • 2007
  • Defining the correlations between rural amenities, while difficult, is important for the adequate and efficient development of these amenities. In this research, an Interactional Information Measuring Technique(IIMT) using Information Gathering and Utilizing System(IGUS) was developed to objectively analyze the correlations between abstract ideas. In order to analyze correlations between rural amenities, this model used the Korean Dusan World Encyclopedia as IGUS and the relative interactional information was measured. The correlations between rural amenities were analyzed objectively using IIMT with the results satisfying the basic conditions of interactional information suggested in this research.