材料と環境
Online ISSN : 1881-9664
Print ISSN : 0917-0480
ISSN-L : 0917-0480
極値統計による給湯用銅管上の最大孔食深さ推定における単位測定区画の大きさと数とに関する検討
小向 茂笠原 晃明
著者情報
ジャーナル フリー

1994 年 43 巻 5 号 p. 258-264

詳細
抄録
The application of extreme-value statistics to the problem of predicting the growth of Type II pits on hot water pipes is described. Optimum combinations of the size and number of unit samples required for reasonable extreme-value prediction were studied by using sets of pit depth data on pipes removed after seven years of field service, covering return periods of up to 1670. Based on the results of the analysis, the following conclusions can be drawn concerning the optimum conditions for obtaining a reasonable extreme-value prediction.
(1) The number and size of unit samples for the extreme-value survey should be determined so that the variance of error of extreme-value estimates is minimized within specific distribution parameters, while the standard deviation of the estimates is limited to one-third of the mode of distribution.
(2) To improve the accuracy of the estimates, increasing the unit sample size may be more effective than increasing the sample number.
(3) As a practical guideline, extreme-value analysis of a sample amounting to 3% of the whole, with a return period of less than 500, is taken to be necessary in order to increase the reliability of extreme-value prediction.
著者関連情報
© 社団法人腐食防食協会
前の記事 次の記事
feedback
Top