moranda.geometric {Reliability} | R Documentation |
moranda.geometric
computes the Maximum Likelihood estimates for the parameters D
and theta
of the mean value function for the Moranda-Geometric model.
moranda.geometric(t, init = c(0, 1), tol = .Machine$double.eps^0.25)
t |
time between failure data |
init |
initial values for Maximum Likelihood fit of the mean value function for the Moranda-Geometric model. |
tol |
the desired accuracy |
This function estimates the parameters D
and theta
of the mean value
function for the Moranda-Geometric model. With Maximum Likelihood estimation one gets the
following equation, which have to be minimized, to get phi
. This is
frac{sum_{i = 1}^{n} i phi^i t_i}{sum_{i = 1}^{n} phi^i t_i} - frac{n + 1}{2} = 0.
The solution of these is then put in in the following equation in order to get D
D = frac{phi n}{sum_{i = 1}^{n} phi^i t_i}.
Where t is the time between failure data and n is the length or in other words the size of the time between failure data.
A list containing following components:
rho |
Maximum Likelihood estimate for rho |
theta |
Maximum Likelihood estimate for theta |
Andreas Wittmann andreas_wittmann@gmx.de
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/
moranda.geometric.plot
, mvf.mor
# 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) moranda.geometric(t)