Nonparametric Estimation for Ramp Stress Tests with Stress Bound under Intermittent Inspection

Lee Nak-Young,; Ahn Ung-Hwan,

Journal of Korean Society for Quality Management > Volume 32(4); 2004 > Article

Journal of Korean Society for Quality Management 2004;32(4): 208-.

단속적 검사에서 스트레스한계를 가지는 램프스트레스시험을 위한 비모수적 추정

이낙영¹, 안웅환²

¹충남대학교 수학ㆍ정보통계학부
²한국표준과학연구원 기술이전그룹

Nonparametric Estimation for Ramp Stress Tests with Stress Bound under Intermittent Inspection

ABSTRACT

This paper considers a nonparametric estimation of lifetime distribution for ramp stress tests with stress bound under intermittent inspection. The test items are inspected only at specified time points an⊂1 so the collected observations are grouped data. Under the cumulative exposure model, two nonparametric estimation methods of estimating the lifetime distribution at use condition stress are proposed for the situation which the time transformation function relating stress to lifetime is a type of the inverse power law. Each of items is initially put on test under ramp stress and then survivors are put on test under constant stress, where all failures in the Inspection interval are assumed to occur at the midi)oint or the endpoint of that interval. Two proposed estimators of quantile from grouped data consisting of the number of items failed in each inspection interval are numerically compared with the maximum likelihood estimator(MLE) based on Weibull distribution.

Key Words: nonparametric estimation;ramp stress tests;intermittent inspection;