부산대학교 도서관

Considerable attention has been paid recently to the behaviour of the hazard rate function h(t) as a function of time. This discussion has led to a lot of speculation as to the shape of the traditional 'bath- tub' curve showing failure or hazard rate as a function of time. Studies at the International Electronics Reliability Institute (IERI) at Loughborough University of Technology, in the United Kingdom, have recently been examining in detail the database created from field failure returns on a wide spectrum of electronic components. These components are in equipment subject to a spread of environmental conditions. The database created has been exercised with particular reference to the behaviour of MOS Ics, rectangular connectors, bipolar transistors and pn-junction diodes. Data has been analysed using pooled information from a wide variety of sources and also from two specific environmental conditions, ground benign and ground mobile. The results of this analysis are presented and the failure intensities as a function of time are given at 1000 hour intervals up to a total time of 21,000 hours. Confidence limits at the 95 per cent X² level are also given. The results show a rapidly falling failure intensity for the first few thousand hours and after this time the failure intensity appears to be relatively constant given the accuracy obtainable with the data available. [ABSTRACT FROM AUTHOR]