Approximate confidence limit procedures for complex systems.

140 Pages·2.1 MB·en_US

by  Yee, Kah-Chee.;Woods, W. Max.

NAVAL POSTGRADUATE SCHOOL
Monterey, California
THESIS
APPROXIMATE
CONFIDENCE LIMIT PROCEDURES
FOR COMPLEX SYSTEMS
by
YEE, Kah-Chee
September, 1991
WOODS
Thesis Advisor: W. M.
Approved for public release; distribution is unlimited.
T2S93PP

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11 TITLE(IncludeSecurityClassification)
APPROXIMATECONFIDENCELIMITPROCEDURESFORCOMPLEXSYSTEMS
12.PERSONALAUTHOR(S) YEE, Kah-Chee
13a TYPEOFREPORT 13b TIMECOVERED 14 DATEOFREPORT(year,month,day) 15 PAGECOUNT
Master'sThesis From To 1991,September 129
16.SUPPLEMENTARYNOTATION
TheviewsexpressedinthisthesisarethoseoftheauthoranddonotreflecttheofficialpolicyorpositionoftheDepartmentofDefenseortheU.S.
Government.
17 COSATICODES 18 SUBJECTTERMS(continueonreverseifnecessaryandidentifybyblocknumber)
FIELD GROUP SUBGROUP CONFIDENCELIMITPROCEDURES,COMPLEXSYSTEMS,LIFETESTING,
SERIESSYSTEMS,SYSTEMRELIABILITYRELIABILITY
19 ABSTRACT(continueonreverseifnecessaryandidentifybyblocknumber)
Lowerconfidencelimitestimationproceduresforthereliabilityofseveralsystemsaredevelopedandtheiraccuraciesevaluatedusingcomputer
simulation. TheproceduresusetestdataoncomponentsofthesystemwhichcanhavefailuretimeswitheitherexponentialorWeibull
distributionsorboth. Testingscenariosforthecomponentscanbetruncatedbynumberoffailuresorbyplannedtesttimes.
Althoughtheevaluationeffortwasfocussedonseriessystemsinthisthesis,theproceduresreadilyapplytoothersystemsasdescribedinthe
thesis. Theevaluationsdemonstratetheprocedurestobequiteaccuratewhensufficientcomponenttestingisperformed.
TwoFORTRANcomputerprogramswerewrittentoperformtheevaluation. TheyareannotatedinUsers'Guidesandcanbeusedtodetermine
theaccuracyoftheseapproximatelowerconfidencelimitproceduresforagivenspecificsystemandassociatedsetofinputparameters.
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Approved for public release; distribution is unlimited.
Approximate Confidence Limit Procedures
For Complex Systems
by
YEE, Kah-Chee
SINGAPORE
Operations Analyst, Ministry of Defence,
B.Eng(Mech), National University of Singapore, 1987
Submitted in partial fulfillment
of the requirements for the degree of
MASTER OF SCIENCE IN OPERATIONS RESEARCH
from the
NAVAL POSTGRADUATE SCHOOL
September 1991
ABSTRACT
Lower confidence limit estimation procedures for the reliability of several
systems are developed and their accuracies evaluated using computer simulation.
The procedures use test data on components of the system which can have failure
times with either exponential or Weibull distributions or both. Testing scenarios for
the components can be truncated by number of failures or by planned test times.
Although the evaluation effortwas focussed onseries systems in this thesis, the
procedures readily apply to other systems as described in the thesis. The evaluations
demonstrate the procedures to be quite accurate when sufficient component testing
is performed.
Two FORTRAN computer programs were written to perform the evaluation.
They are annotated in Users' Guides and can be used to determine the accuracy of
these approximate lower confidence limit procedures for a given specific system and
associated set of input parameters.
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6.1
THESIS DISCLAIMER
The reader is cautioned that the computer programs developed in this
research may not have been exercised for all cases ofinterest. While every effort has
been made, within the time available, to ensure that the programs are free of
computational and logic errors, they cannot be consideredvalidated. Anyapplication
of these programs without additional verification is at the risk of the user.
IV