littlewood.verall.plot: Plotting the mean value function for the Littlewood-Verall...

In Reliability: Functions for estimating parameters in software reliability models

Description

littlewood.verall.plot plots the mean value function for the Littlewood-Verall model and the raw data into one window.

Usage

littlewood.verall.plot(theta0, theta1, rho, t, linear = T, xlab = "time", 
    ylab = "Cumulated failures and estimated mean value function", 
    main = NULL)

Arguments

theta0	parameter value for theta0
theta1	parameter value for theta1
rho	parameter value for rho
t	time between failure data
linear	logical. Should the linear or the quadratic form of the mean value function for the Littlewood-Verrall model be used of computation? If TRUE, which is the default, the linear form of the mean value function is used.
xlab	a title for the x axis
ylab	a title for the y axis
main	an overall title for the plot

Details

This function gives a plot of the mean value function for the Littlewood-Verall model. Here the estimated parameter values for theta0, theta1 and theta, which are obtained by using littlewood.verall, can be put in. Internally the functions mvf.ver.lin or mvf.ver.quad are used to get the mean value function for the Littlewood-Verall model. This depends on the calibration, if the linear or the quadratic form of the mean value function for the Littlewood-Verall model should be used.

Value

A graph of the mean value function for the Littlewood-Verall model and of the raw data.

Author(s)

Andreas Wittmann andreas\[e-mail]

References

J.D. Musa, A. Iannino, and K. Okumoto. Software Reliability: Measurement, Prediction, Application. McGraw-Hill, 1987.

Michael R. Lyu. Handbook of Software Realibility Engineering. IEEE Computer Society Press, 1996. http://www.cse.cuhk.edu.hk/~lyu/book/reliability/

See Also

littlewood.verall, mvf.ver.lin, mvf.ver.quad

Examples

# time between-failure-data from DACS Software Reliability Dataset
# homepage, see system code 1. Number of failures is 136.
t <- c(3, 30, 113, 81, 115, 9, 2, 20, 20, 15, 138, 50, 77, 24,
       108, 88, 670, 120, 26, 114, 325, 55, 242, 68, 422, 180,
       10, 1146, 600, 15, 36, 4, 0, 8, 227, 65, 176, 58, 457,
       300, 97, 263, 452, 255, 197, 193, 6, 79, 816, 1351, 148,
       21, 233, 134, 357, 193, 236, 31, 369, 748, 0, 232, 330,
       365, 1222, 543, 10, 16, 529, 379, 44, 129, 810, 290, 300,
       529, 281, 160, 828, 1011, 445, 296, 1755, 1064, 1783, 
       860, 983, 707, 33, 868, 724, 2323, 2930, 1461, 843, 12,
       261, 1800, 865, 1435, 30, 143, 108, 0, 3110, 1247, 943,
       700, 875, 245, 729, 1897, 447, 386, 446, 122, 990, 948,
       1082, 22, 75, 482, 5509, 100, 10, 1071, 371, 790, 6150,
       3321, 1045, 648, 5485, 1160, 1864, 4116)
      
theta0 <- littlewood.verall(t, linear = TRUE)$theta0
theta1 <- littlewood.verall(t, linear = TRUE)$theta1
rho <- littlewood.verall(t, linear = TRUE)$rho
littlewood.verall.plot(theta0, theta1, rho, t, linear = TRUE, 
  xlab = "time (in seconds)", main = "Littlewood-Verall model (linear)")

## Not run: 
## theta0 <- littlewood.verall(t, linear = FALSE)$theta0
## theta1 <- littlewood.verall(t, linear = FALSE)$theta1
## rho <- littlewood.verall(t, linear = FALSE)$rho
## littlewood.verall.plot(theta0, theta1, rho, t, linear = FALSE, 
##   xlab = "time (in seconds)", main = "Littlewood-Verall modell (quadratic)")
## End(Not run)

Example output

Reliability documentation built on May 1, 2019, 9:22 p.m.