ALTopt (version 0.1.0)

ALTopt-package: Optimal Experimental Designs for Accelerated Life Testing

Description

This package creates the optimal (D, U and I) designs for the accelerated life testing with right censoring or interval censoring. It uses generalized linear model (GLM) approach to derive the asymptotic variance-covariance matrix of regression coefficients. The failure time distribution is assumed to follow Weibull distribution with a known shape parameter and log-linear link functions are used to model the relationship between failure time parameters and stress variables. Any number of stress factors can be used but no more than 3 are recommended due to the computational time. ALTopt package also provides several plotting functions including contour plot, Fraction of Use Space (FUS) plot and Variance Dispersion graphs of Use Space (VDUS) plot.

Details

ll{ Package: ALTopt Version: 0.1.0 Authors@R: as.person(c( "Kangwon Seo [aut, cre]", "Rong Pan [aut]" )) Depends: R (>= 3.0.0) License: GPL-3 LazyData: true Imports: cubature (>= 1.0), lattice (>= 0.20) Built: R 3.1.2; ; 2015-01-13 00:42:55 UTC; windows } Index: alteval.ic Design evaluation with interval censoring. alteval.rc Design evaluation with right censoring. altopt.ic Optimal design with interval censoring. altopt.rc Optimal design with right censoring. compare.fus Comparing designs using FUS compare.vdus Comparing designs using VDUS convert.stress.level Coding and decoding stress level design.plot Design plot. pv.contour.ic Contour plot of prediction variance for a design with interval censoring. pv.contour.rc Contour plot of prediction variance for a design with right censoring. pv.fus.ic FUS (Fraction of Use Space) plot for interval censoring. pv.fus.rc FUS (Fraction of Use Space) plot for right censoring. pv.vdus.ic VDUS (Variance Dispersion of Use Space) plot for interval censoring. pv.vdus.rc VDUS (Variance Dispersion of Use Space) plot for right censoring.

References

Monroe, E. M., Pan, R., Anderson-Cook, C. M., Montgomery, D. C. and Borror C. M. (2011) A Generalized Linear Model Approach to Designing Accelerated Life Test Experiments, Quality and Reliability Engineering International 27(4), 595--607 Yang, T., Pan, R. (2013) A Novel Approach to Optimal Accelerated Life Test Planning With Interval Censoring, Reliability, IEEE Transactions on 62(2), 527--536

See Also

altopt.rc, altopt.ic, alteval.rc, alteval.ic, pv.contour.rc, pv.contour.ic, pv.fus.rc, pv.fus.ic, pv.vdus.rc, pv.vdus.ic, compare.fus, compare.vdus, design.plot, convert.stress.level

Examples

# D optimal design of two stress factors with right censoring.
Design.D <- altopt.rc("D", 100, 100, 2, 1, formula = ~ x1 + x2 + x1:x2,
coef = c(0, -4.086, -1.476, 0.01))

design.plot(Design.D$opt.design.rounded, x1, x2)

pv.contour.rc(Design.D$opt.design.rounded, x1, x2, 100, 2, 1,
formula = ~ x1 + x2 + x1:x2, coef = c(0, -4.086, -1.476, 0.01),
useCond = c(1.758, 3.159))

FUS.D <- pv.fus.rc(Design.D$opt.design.rounded, 100, 2, 1,
formula = ~ x1 + x2 + x1:x2, coef = c(0, -4.086, -1.476, 0.01),
useLower = c(1.458, 2.859), useUpper = c(2.058, 3.459))

# U optimal design of two stress factors with right censoring.
Design.U <- altopt.rc("U", 100, 100, 2, 1, formula = ~ x1 + x2 + x1:x2,
coef = c(0, -4.086, -1.476, 0.01), useCond = c(1.758, 3.159))

design.plot(Design.U$opt.design.rounded, x1, x2)

pv.contour.rc(Design.U$opt.design.rounded, x1, x2, 100, 2, 1,
formula = ~ x1 + x2 + x1:x2, coef = c(0, -4.086, -1.476, 0.01),
useCond = c(1.758, 3.159))

FUS.U <- pv.fus.rc(Design.U$opt.design.rounded, 100, 2, 1,
formula = ~ x1 + x2 + x1:x2, coef = c(0, -4.086, -1.476, 0.01),
useLower = c(1.458, 2.859), useUpper = c(2.058, 3.459))

# Comparing D and U optimal design.
compare.fus(FUS.D, FUS.U)