Two Methods to Estimate the Change Points of a Bathtub Curve
Volume 9, Number 5, September 2013 - Paper 12 - pp. 569-579
RENYAN JIANGFaculty of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha, Hunan 410114, CHINA
(Received on February 10, 2013, revised on June 20, 2013)
The failure rate function of non-repairable components can be bathtub shaped. Two change points can be defined for a bathtub failure rate curve, which can be viewed as the partition points between the early use, normal use and wear-out phases. There is practical significance to determine the change points, and several non-parametric methods have been developed for this purpose. This paper presents two parametric methods to determine the change points of the bathtub curve. The proposed methods are based on a bathtub curve model with a finite support. A maximum likelihood method with a constraint is developed to estimate the parameters of this model. The methods are illustrated by three real-world examples.
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