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Young Hwan Choi - One of the best experts on this subject based on the ideXlab platform.
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Application of piping failure Database to nuclear safety issues in Korea
International Journal of Pressure Vessels and Piping, 2011Co-Authors: Jeong Soon Park, Young Hwan ChoiAbstract:Abstract This paper describes analyses and application of OPDE (OECD Piping Data Failure Exchange) Database and NPFD (Nuclear Piping Failure Database) to some safety related issues for Korea nuclear power plants. Safety issues considered in this study include the piping rupture frequency assessment, the screening criteria of the leak before break application, and the augmented in-service inspection and the risk-informed ISI (RI-ISI). As a result of this study: (1) Piping rupture frequencies of the very small LOCA, feedwater line break events, and flood events were evaluated and used as initiating event frequencies for the PSA of Korean PWR plants; (2) Based on the review of OPDE DB and LBB screening criteria, LBB application to the pressurizer surge line, safety injection system, and shutdown cooling system were approved under the conditions that detailed thermal stress analyses should be performed to the systems. (3) For RI-ISI application, major degradation mechanisms in the reactor coolant system were analyzed based on the analysis of the OPDE and NPFD and augmented inspections were enforced to the pipe segments susceptible to degradation mechanism such as thermal stratification/fatigue.
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Application of a Piping Failure Database to Some Nuclear Safety Issues in Korea
12th International Conference on Nuclear Engineering Volume 1, 2004Co-Authors: Sun Yeong Choi, Young Hwan Choi, Yeon Ki ChungAbstract:The purpose of this paper is to introduce some experience from the application of a piping failure Database to some nuclear safety issues in Korea. We used both a Korean piping failure Database and the OPDE (OECD Piping Data Failure Exchange) Database for the following issues in Korea, the inservice inspection (ISI) including the augmented inspection and the risk-informed ISI (RI-ISI), the screening criteria of the leak before break (LBB) application, the plant aging management in the periodic safety review (PSR), and the re-evaluation of the initiating event frequencies for the probabilistic safety assessment (PSA). The following are the results obtained from this study. (1) The rupture frequency of the main feedwater system for the PSA purpose was estimated as 4.54E−3/cr.yr, while that in the United States was 3.43E−3/cr.yr. (2) The piping failure frequencies of the five failed piping systems such as the CVCS, the primary sampling system, the main feedwater system, the essential service water system, and the CANDU purification system with the pipe population data in Korea were estimated in the range from 6.08E−5/cr.yr to 1.15E−3/cr.yr. (3) The evaluation of the screening criteria for the LBB application showed that detailed analyses are required because the pressurizer surge line, the safety injection system, and the shutdown cooling system were susceptible to thermal fatigue, and the main feedwater system was susceptible to flow accelerated corrosion (FAC) and thermal fatigue. (4) Based on the piping failure event data, augmented inspections are required for the piping systems susceptible to thermal fatigue and FAC in Korea. (5) The insight obtained from the piping failure Database was used in the determination of the ranking for the plant aging management in the PSR of the Kori Unit 1.
M. A. Espy - One of the best experts on this subject based on the ideXlab platform.
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Analyzing powers for the {Pi}{sup -}{r_arrow ovr p} {r_arrow} {pi}{degrees}n reaction across the {delta}(1232) resonance.
Physical Review C, 1999Co-Authors: C. V. Gaulard, C. M. Riedel, J. R. Comfort, J.f. Amann, M. E. Beddo, R. L. Boudrie, G. R. Burleson, Philip L. Cole, K. Craig, M. A. EspyAbstract:High quality analyzing powers for the {Pi}{sup -}p{yields}{yields}{Pi}{sup 0}n reaction have been obtained with a polarized proton target over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. This experiment nearly doubled the existing {Pi}N single-charge-Exchange Database for energies ranging from 10 to 230 MeV, with 36 new analyzing powers. The Neutral Meson Spectrometer was used to detect the outgoing neutral pions. The data are well described by recent phase-shift analyses. When combined with high-precision and accurate cross section data at the same energies, the data can provide a good test of the degree of isospin breaking in the region of the {Delta}(1232) resonance. They will also be helpful for constraining the evaluation of the pion-nucleon {sigma} term from the scattering amplitudes.
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Analyzing powers for the π − p → → π 0 n reaction across the Δ ( 1232 ) resonance
Physical Review C, 1999Co-Authors: C. V. Gaulard, C. M. Riedel, J. R. Comfort, J.f. Amann, M. E. Beddo, R. L. Boudrie, G. R. Burleson, Philip L. Cole, K. Craig, M. A. EspyAbstract:High quality analyzing powers for the ${\ensuremath{\pi}}^{\ensuremath{-}}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}n$ reaction have been obtained with a polarized proton target over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. This experiment nearly doubled the existing $\ensuremath{\pi}N$ single-charge-Exchange Database for energies ranging from 10 to 230 MeV, with 36 new analyzing powers. The Neutral Meson Spectrometer was used to detect the outgoing neutral pions. The data are well described by recent phase-shift analyses. When combined with high-precision and accurate cross section data at the same energies, the data can provide a good test of the degree of isospin breaking in the region of the $\ensuremath{\Delta}(1232)$ resonance. They will also be helpful for constraining the evaluation of the pion-nucleon $\ensuremath{\sigma}$ term from the scattering amplitudes.
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Analyzing powers for the p 2 p ¢ òp 0 n reaction across the DÑ1232Ö resonance
1999Co-Authors: C. V. Gaulard, C. M. Riedel, J. R. Comfort, J.f. Amann, M. E. Beddo, R. L. Boudrie, G. R. Burleson, Philip L. Cole, K. K. Craig, M. A. EspyAbstract:n reaction have been obtained with a polarized protontarget over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. Thisexperiment nearly doubled the existing pN single-charge-Exchange Database for energies ranging from 10 to230 MeV, with 36 new analyzing powers. The Neutral Meson Spectrometer was used to detect the outgoingneutral pions. The data are well described by recent phase-shift analyses. When combined with high-precisionand accurate cross section data at the same energies, the data can provide a good test of the degree of isospinbreaking in the region of the D(1232) resonance. They will also be helpful for constraining the evaluation ofthe pion-nucleons term from the scattering amplitudes. @S0556-2813~99!02408-5#PACS number~s!: 25.80.Gn, 24.70.1s, 13.75.GxI. INTRODUCTION
Jaromír Vrbka - One of the best experts on this subject based on the ideXlab platform.
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Prediction of stock price developments using the Box-Jenkins method
SHS Web of Conferences, 2017Co-Authors: Bořivoj Groda, Jaromír VrbkaAbstract:Stock prices develop in a non-linear way. Naturally, the stock price prediction is one of the most important issues at stock markets. Therefore, a variety of methods and technologies is devoted to the prediction of these prices. The present article predicts the future development of the stock price of CEZ, a. s., on the Prague Stock Exchange using the ARIMA method - the Box-Jenkins method. The analysis employs the final price of the last trading day in a given month, from February 2012 to September 2017. The data come from the Prague Stock Exchange Database. Statistica software is used for processing the data, namely advanced time series prediction methods, the ARIMA tool, and autocorrelation functions. First, the current stock development of CEZ, a.s., was graphically evaluated, and this was followed by a stock price prediction for the next 60 days in which the shares would be traded. Lastly, the prediction residues were analysed. It was confirmed that the calculation was done correctly, but with little accuracy. The conclusion is an assertion that the Box-Jenkins method is not a suitable tool for prediction.
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Stock price development forecasting using neural networks
SHS Web of Conferences, 2017Co-Authors: Jaromír Vrbka, Zuzana RowlandAbstract:Stock price forecasting is highly important for the entire market economy as well as the investors themselves. However, stock prices develop in a non-linear way. It is therefore rather complicated to accurately forecast their development. A number of authors are now trying to find a suitable tool for forecasting the stock prices. One of such tools is undoubtedly artificial neural network, which have a potential of accurate forecast based even on non-linear data. The objective of this contribution is to use neural networks for forecasting the development of the CEZ, a. s. stock prices on the Prague Stock Exchange for the next 62 trading days. The data for the forecast have been obtained from the Prague Stock Exchange Database. These are final prices at the end of each trading day when the company shares were traded, starting from the beginning of the year 2012 till September 2017. The data are processed by the Statistica software, generating multiple layer perceptron (MLP) and radial basis function (RBF) networks. In total, there are 10,000 neural network structures, out of which 5 with the best characteristics are retained. Using statistical interpretation of the results obtained, it was found that all retained networks are applicable in practice.
Yeon Ki Chung - One of the best experts on this subject based on the ideXlab platform.
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Application of a Piping Failure Database to Some Nuclear Safety Issues in Korea
12th International Conference on Nuclear Engineering Volume 1, 2004Co-Authors: Sun Yeong Choi, Young Hwan Choi, Yeon Ki ChungAbstract:The purpose of this paper is to introduce some experience from the application of a piping failure Database to some nuclear safety issues in Korea. We used both a Korean piping failure Database and the OPDE (OECD Piping Data Failure Exchange) Database for the following issues in Korea, the inservice inspection (ISI) including the augmented inspection and the risk-informed ISI (RI-ISI), the screening criteria of the leak before break (LBB) application, the plant aging management in the periodic safety review (PSR), and the re-evaluation of the initiating event frequencies for the probabilistic safety assessment (PSA). The following are the results obtained from this study. (1) The rupture frequency of the main feedwater system for the PSA purpose was estimated as 4.54E−3/cr.yr, while that in the United States was 3.43E−3/cr.yr. (2) The piping failure frequencies of the five failed piping systems such as the CVCS, the primary sampling system, the main feedwater system, the essential service water system, and the CANDU purification system with the pipe population data in Korea were estimated in the range from 6.08E−5/cr.yr to 1.15E−3/cr.yr. (3) The evaluation of the screening criteria for the LBB application showed that detailed analyses are required because the pressurizer surge line, the safety injection system, and the shutdown cooling system were susceptible to thermal fatigue, and the main feedwater system was susceptible to flow accelerated corrosion (FAC) and thermal fatigue. (4) Based on the piping failure event data, augmented inspections are required for the piping systems susceptible to thermal fatigue and FAC in Korea. (5) The insight obtained from the piping failure Database was used in the determination of the ranking for the plant aging management in the PSR of the Kori Unit 1.
C. V. Gaulard - One of the best experts on this subject based on the ideXlab platform.
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Analyzing powers for the {Pi}{sup -}{r_arrow ovr p} {r_arrow} {pi}{degrees}n reaction across the {delta}(1232) resonance.
Physical Review C, 1999Co-Authors: C. V. Gaulard, C. M. Riedel, J. R. Comfort, J.f. Amann, M. E. Beddo, R. L. Boudrie, G. R. Burleson, Philip L. Cole, K. Craig, M. A. EspyAbstract:High quality analyzing powers for the {Pi}{sup -}p{yields}{yields}{Pi}{sup 0}n reaction have been obtained with a polarized proton target over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. This experiment nearly doubled the existing {Pi}N single-charge-Exchange Database for energies ranging from 10 to 230 MeV, with 36 new analyzing powers. The Neutral Meson Spectrometer was used to detect the outgoing neutral pions. The data are well described by recent phase-shift analyses. When combined with high-precision and accurate cross section data at the same energies, the data can provide a good test of the degree of isospin breaking in the region of the {Delta}(1232) resonance. They will also be helpful for constraining the evaluation of the pion-nucleon {sigma} term from the scattering amplitudes.
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Analyzing powers for the π − p → → π 0 n reaction across the Δ ( 1232 ) resonance
Physical Review C, 1999Co-Authors: C. V. Gaulard, C. M. Riedel, J. R. Comfort, J.f. Amann, M. E. Beddo, R. L. Boudrie, G. R. Burleson, Philip L. Cole, K. Craig, M. A. EspyAbstract:High quality analyzing powers for the ${\ensuremath{\pi}}^{\ensuremath{-}}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}n$ reaction have been obtained with a polarized proton target over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. This experiment nearly doubled the existing $\ensuremath{\pi}N$ single-charge-Exchange Database for energies ranging from 10 to 230 MeV, with 36 new analyzing powers. The Neutral Meson Spectrometer was used to detect the outgoing neutral pions. The data are well described by recent phase-shift analyses. When combined with high-precision and accurate cross section data at the same energies, the data can provide a good test of the degree of isospin breaking in the region of the $\ensuremath{\Delta}(1232)$ resonance. They will also be helpful for constraining the evaluation of the pion-nucleon $\ensuremath{\sigma}$ term from the scattering amplitudes.
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Analyzing powers for the p 2 p ¢ òp 0 n reaction across the DÑ1232Ö resonance
1999Co-Authors: C. V. Gaulard, C. M. Riedel, J. R. Comfort, J.f. Amann, M. E. Beddo, R. L. Boudrie, G. R. Burleson, Philip L. Cole, K. K. Craig, M. A. EspyAbstract:n reaction have been obtained with a polarized protontarget over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. Thisexperiment nearly doubled the existing pN single-charge-Exchange Database for energies ranging from 10 to230 MeV, with 36 new analyzing powers. The Neutral Meson Spectrometer was used to detect the outgoingneutral pions. The data are well described by recent phase-shift analyses. When combined with high-precisionand accurate cross section data at the same energies, the data can provide a good test of the degree of isospinbreaking in the region of the D(1232) resonance. They will also be helpful for constraining the evaluation ofthe pion-nucleons term from the scattering amplitudes. @S0556-2813~99!02408-5#PACS number~s!: 25.80.Gn, 24.70.1s, 13.75.GxI. INTRODUCTION
