SEMINAR ON RELIABILITY THEORY AND ITS APPLICATIONS | Year:2015 | دوره:1 |Papers Count:40

A MULTICOMPONENT STRESS-STRENGTH SYSTEM IS CONSIDERED, WHILE THE STRESS AND THE STRENGTH SYSTEM HAVE NON-IDENTICAL EXPONENTIATED EXPONENTIAL DISTRIBUTIONS WITH DIFFERENT PARAMETERS. THE ESTIMATION OF STRESS-STRENGTH RELIABILITY PARAMETER IS STUDIED. ...

IN MODELING OF BIOLOGICAL AND ENGINEERING SYSTEMS OFTEN REQUIRES USE OF CONCEPTS OF INFORMATION THEORY, AND IN PARTICULAR OF ENTROPY. THE CONCEPT OF RESIDUAL ENTROPY IS APPLICABLE TO A SYSTEM WHICH HAS SURVIVED FOR SOME UNITS OF TIME. IN THIS PAPER, WE PROPOSE A GENERALIZED RESIDUAL ENTROPY BASED ON ORDER STATISTICS AND OBTAIN SOME RESULTS ON THE STOCHASTIC COMPARISONS OF IT. ...

LIFETIME PERFORMANCE INDEX (CL) IS A EXIBLE AND E_ECTIVE TOOL FOR EVALUATING PROD- UCT QUALITY AND CONFORMING RATE. RANKED SET SAMPLING (RSS) SCHEME IS APPLIED FOR BAYSIAN ESTIMATOR OF CL BASED ON SQUARE ERROR LOSS. WE ASSUME THAT LIFETIMES OF PROD- UCTS FOLLOW A ONE-PARAMETER EXPONENTIAL DISTRIBUTION. THE SIMULATION RESULT FOR THIS SCHEME IS COMPARED WITH SIMPLE RANDOM SAMPLE (SRS) SCHEME BASED ON BIAS, RISK, PITMAN NEARNESS, RELATIVE E_CIENCY. ...

REDUNDANCY IS A TECHNIQUE THAT HAS BEEN WIDELY APPLIED TO IMPROVE THE SYSTEM RELIABILITY AND ITS AVAILABILITY. IN THIS PAPER, A NEW SWITCHING MODEL IS PROPOSED TO INCREASE THE RELIABILITY OF A UNIT (SYSTEM) WITH A COLD STANDBY BACKUP. IT IS ASSUMED THAT THE SWITCH OVER TO THE STANDBY UNIT IS NOT FAILURE-FREE, CONTRARY TO WHAT WE HAVE IN STANDBY REDUNDANCY. THE OPTIMAL TIME TO SWITCH BETWEEN THE KEY UNIT AND ITS COLD STANDBY BACKUP IS _ND SUCH THAT THE MEAN LIFETIME OF THE SYSTEM TO BE MAXIMIZED. FINALLY, AN EXAMPLE IS PRESENTED TO COMPARE THE MEAN LIFETIME OF THE PROPOSED SWITCH- ING MODEL AND A SYSTEM WITH PARALLEL REDUNDANCY. ...

IN THIS PAPER, WE FOCUS ON THE PROBLEM OF ESTIMATION FOR THE SCALE AND SHAPE PARAMETERS OF THE WEIGHTED EXPONENTIAL DISTRIBUTION. THE PROBABILITY WEIGHTED MOMENTS METHOD HAS BEEN DEVELOPED FOR ESTIMATING THE PARAMETERS. A REAL DATA EXAMPLE ENDS THE PAPER.

THE PROPORTIONAL ODDS MODEL PLAYS AN IMPORTANT ROLE IN ANALYZING SURVIVAL DATA.THIS NOTE DEVELOPS THE DEFINITION OF DYNAMIC PROPORTIONAL ODDS (DPO) MODEL AND ITS PROP- ERTIES INCLUDING SOME RESULTS ON STOCHASTIC COMPARISONS. ONE APPLICATION OF DPO MODEL IS CONSIDERED AS MARSHALL AND OLKIN FAMILY OF DISTRIBUTION IN DYNAMIC SITUATION. ...

IN THIS PAPER, WE DISCUSS THE BAYESIAN ESTIMATION PROBLEM FOR THE RAYLEIGH DISTRIBUTION BASED ON UPPER RECORD RANKED SET SAMPLES. THE BAYES ESTIMATORS ARE OBTAINED WITH RESPECT TO TWO DIFFERENT LOSS FUNCTIONS. WE ALSO OBTAIN THE BAYES CONFIDENCE INTERVALS FOR THE PARAMETER OF THE RAYLEIGH DISTRIBUTION. FINALLY, WE PRESENT A SIMULATION STUDY FOR THE PURPOSE OF NUMERICAL COMPARISON. ...

CLASSICAL ESTIMATION PROCEDURES OF THE STRESS-STRENGTH PARAMETER R = PR(X > Y ) ARE BASED ON PRECISE DATA. HOWEVER, IN REAL WORLD SITUATIONS, SOME COLLECTED DATA MIGHT BE IMPRECISE AND ARE REPRESENTED IN THE FORM OF FUZZY NUMBERS. IN THIS PAPER, WE OBTAIN THE MAXIMUM LIKELIHOOD ESTIMATION OF THE PARAMETER R WHEN X AND Y ARE INDEPENDENT LINDLEY RANDOM VARIABLES, AND THE AVAILABLE DATA ARE REPORTED IN THE FORM OF FUZZY NUMBERS. A MONTE CARLO SIMULATION STUDY IS CARRIED OUT IN ORDER TO ASSESS THE ACCURACY OF THE PROPOSED METHOD. ...

IN THIS PAPER, WE STUDY THE ESTIMATION PROBLEM FOR THE EXPONENTIAL-GEOMETRIC DISTRIBUTION UNDER TYPE II PROGRESSIVE CENSORING WITH BINOMIAL REMOVALS. THE MAXIMUM LIKELIHOOD ESTIMATORS AS WELL AS THE ASYMPTOTIC CONFIDENCE INTERVALS FOR THE PARAMETERS ARE DERIVED. FINALLY, A REAL DATA EXAMPLE IS PRESENTED TO ILLUSTRATE THE RESULTS OF THE PAPER. ...

IN THIS PAPER, WE PRESENT SOME RESULTS ON APPLICATIONS OF MEAN VITALITY FUNCTION TO COMPARISONS OF COHERENT SYSTEMS. WE ALSO OBTAIN AN UPPER BOUND FOR THE MEAN VITALITY FUNCTION OF COHERENT SYSTEM WHEN THE LIFETIMES OF COMPONENTS ARE INDEPENDENT AND IDENTICALLY DISTRIBUTED. ...

IN THIS PAPER, WE INVESTIGATE STOCHASTIC COMPARISONS OF LIFETIMES OF PARALLEL AND SERIES SYSTEMS WITH THE MULTIPLE-OUTLIER INDEPENDENT COMPONENTS OF THE SCALE MODELS WITH RESPECT TO LIKELIHOOD RATIO AND DISPERSIVE ORDERS. ...

THE INTENSITY OF THE GLOBAL COMPETITION FOR THE DEVELOPMENT OF NEW PRODUCTS IN A SHORT TIME. TESTING UNDER NORMAL OPERATING CONDITIONS FOR COMPUTE RELIABILITY QUATI- TIES, REQUIRES A VERY LONG TIME. THIS HAS LED TO THE DEVELOPMENT OF ACCELERATED LIFE TESTING (ALT). IN THIS ARTICLE, WE COMPUTE MTTF OF BOURDON TUBES (USED AS A PART OF PRESSURE SENSORS IN AVIONICS) IN STRESS CONDITIION. THE FAILURE IS LEAK IN THE TUBE. BASE ON ANDERSON-DARLING TEST WEIBULL DISTRIBUTION IS APPROPRIATE FOR FITTING DATA UNDER STRESS CONDITION. WE DETERMINE MTTF OF BOURDON TUBES IN OPERATING CONDITION BASE ON ARRHENIUS MODEL AND MEAN OF WEIBULL DISTRIBUTIONS. ...

THIS PAPER CONSIDERS A GENERAL DEGRADATION PATH MODEL AND FAILURE TIME DATA WITH TRAUMATIC FAILURE MODE. IT PROVIDES A REVIEW OF THE NONPARAMETRIC ESTIMATOR OF SURVIVAL FUNCTION, STUDIED BY BAGDONAVICIUS, AND CONSIDERS THE PARAMETRIC ESTIMATION OF SURVIVAL FUNCTION OF FAILURE TIMES WITH A HAZARD RATE IN THE DEGRADATION SPACE. IN ADDITION, WE DISCUSS THE COMPARISON OF BOTH PARAMETRIC AND NONPARAMETRIC METHODS ACCORDING TO SIMULATED AND REAL DATA.

IN THIS PAPER WE CONSIDER ESTIMATION OF THE RELIABILITY CHARACTERISTICS OF BURR TYPEC DISTRIBUTION BASED ON FUZZY LIFETIME DATA. THE BAYES ESTIMATES OF THE PARAMETER AND RELIABILITY FUNCTION OF THE BURR TYPE C MODEL ARE OBTAINED USING A MARKOV CHAIN MONTE CARLO METHOD. SIMULATION STUDIES ARE CONDUCTED TO DEMONSTRATE THE EFFICIENCY OF THE PROPOSED METHOD. ...

IN THIS PAPER, WE INVESTIGATE PROGRESSIVELY TYPE-II CENSORED CONDITIONALLY N-ORDERED STATISTICS ARISING FROM A SYSTEM WITH IDENTICAL AS WELL AS NON-IDENTICAL BUT DEPENDENT COMPONENTS, JOINTLY DISTRIBUTED ACCORDING TO AN ARCHIMEDEAN COPULA WITH COMPLETELY MONOTONE GENERATOR (PCCOSDNARCM-N). OUR RESULTS GENERALIZED THE RESULTS IN BAIRAMOV (2006) AND IS MOREF EXIBLE THAN THOSE IN PRACTICE, BECAUSE OF CONSIDERING THE DEPENDENCY BETWEEN COMPONENTS THAT IS A COMMON FACT FOR REAL DATA.

IN THIS PAPER, SEQUENTIAL K-OUT-OF-N SYSTEMS WITH COMING NON- HOMOGENEOUS EXPO- NENTIAL COMPONENT LIFETIMES ARE CONSIDERED. POINT ESTIMATES OF PARAMETERS AS WELL AS EQUAL-TAIL AND APPROXIMATE CONFIDENCE INTERVALS AND FISHER INFORMATION ARE DERIVED ON THE BASIS OF OBSERVED MULTIPLY SYSTEM LIFETIMES. ...

COMPETING RISKS DATA ARE OFTEN SUMMARIZED USING A FAILURE TIME AND AN INDICATOR OF CAUSE OF FAILURE THAT MAY NOT BE OBSERVED FOR SOME SUBJECTS. IN SUCH CASE, STAN- DARD ANALYSIS THROUGH COMPLETE CASE MAY LEAD TO BIASED INFERENCES WHEN THE MISSING MECHANISM IS NOT IGNORABLE. IN THIS PAPER, WE PROPOSE A BAYESIAN INDEX OF LOCAL SEN- SITIVITY TO NON-IGNORABILITY (ISNI) FOR MODELING COMPETING RISKS DATA IN THE PRESENCE OF HYBRID CENSORING WHEN THE COMPETING RISKS HAVE WEIBULL DISTRIBUTION WITH THE SAME SHAPE PARAMETER, BUT DI_ERENT SCALE PARAMETERS. THE RESULTS OF APPLYING THE ABOVE INDEX ON A SET OF REAL DATA SHOW THAT THE MODEL COULD HAVE POTENTIAL SENSITIVITY TO NON-IGNORABILITY FOR SCALE PARAMETERS BUT NOT FOR THE COMMON SHAPE PARAMETER. ...

IN RECENT YEARS, A LARGE NUMBER OF RESEARCH WORKS ARE APPEARED IN THE LITERATURE DEALING WITH THE PROPERTIES AND APPLICATIONS OF THE SKEW DISTRIBUTIONS. SKEW DISTRI-BUTIONS ARE SHOWN TO BE EXIBLE MODELS FOR DESCRIBING DI_ERENT KIND OF DATA. IN THE PRESENT STUDY, WE CONSIDER MULTIVARIATE SKEW-NORMAL DISTRIBUTION, AND OBTAIN SOME OF ITS PROPERTIES. THESE PROPERTIES HELP US TO EXPLORE THE STRESS-STRENGTH MODEL BASED ON THE MULTIVARIATE SKEW-NORMAL DISTRIBUTION. ...

CONSIDER A SYSTEM CONSISTING OF N BINARY COMPONENTS WITH DIFFERENT CONTRIBUTIONS (WEIGHTS) ON DETERMINING THE STATE OF THE SYSTEM. THE SYSTEM IS KNOWN AS WEIGHTED-K- OUT-OF-N SYSTEM WHEN IT WORKS IF THE TOTAL WEIGHT OF WORKING COMPONENTS ARE GREATER THAN A PRE-SPECIIFED VALUE K. SUPPOSE THAT THIS SYSTEM HAS THE PROPERTY THAT, WITH PROBABILITY 1, OPERATES AS LONG AS AT LEAST N-S+1 COMPONENTS OPERATE (S £N). IN THIS PAPER, WE COMPARE TWO SUCH SYSTEMS WITH RESPECT TO THEIR MEAN RESIDUAL LIFE FUNCTION UNDER THE CONDITION THAT N - R + 1 COMPONENTS (R£ S) OF THE SYSTEMS ARE WORKING AT TIME T. ...

IN THIS PAPER, THE RESIDUAL LIFETIME OF A REPAIRABLE SYSTEM IS STUDIED WHEN THE FAIL- URE STATUS OF THE SYSTEM IS KNOWN. A MIXTURE REPRESENTATION OF THE RELIABILITY FUNCTION OF THE CONDITIONAL RESIDUAL LIFETIME OF A REPAIRABLE SYSTEM IN TERMS OF THE RELIABILITY FUNCTION OF RESIDUAL RECORDS IS PROVIDED. SOME STOCHASTIC PROPERTIES OF THE CONDITIONAL PROBABILITIES AND THE RESIDUAL LIFETIMES ALSO ARE GIVEN. ...

IN THIS PAPER, WE CONSIDER A SINGLE-STEP NETWORK CONSISTS OF N LINKS AND ASSUME THAT THE LINKS ARE SUBJECT TO FAILURE. IT IS ASSUMED THAT THE NETWORK CAN BE IN THREE STATES, UP (K=2), PARTIAL PERFORMANCE (K=1) AND DOWN (K=0). UNDER DI_ERENT SCENARIOS ON THE STATES OF THE NETWORK AND USING THE CONCEPT OF TWO-DIMENSIONAL SIGNATURE, WE OBTAIN THE PROBABILITIES THAT I LINKS FAIL AT TIME T1 AND J LINKS FAIL AT TIME T. SEVERAL STOCHASTIC AND AGING PROPERTIES OF THE PROPOSED PROBABILITIES ARE STUDIED.

THE PURPOSE OF THE TALK IS TO STUDY THE INACTIVITY TIME OF FAILED COMPONENTS OF A COHERENT SYSTEM CONSISTING OF N IDENTICAL COMPONENTS WITH STATISTICALLY INDEPENDENT LIFETIMES. DIFFERENT AGING AND STOCHASTIC PROPERTIES OF THIS CONDITIONAL RANDOM VARIABLE ARE OBTAINED. ALSO WE INVESTIGATE STOCHASTIC PROPERTIES OF THE INACTIVITY TIME IN THE CASE WHERE THE COMPONENT LIFETIMES ARE DEPENDENT RANDOM VARIABLES. SOME RESULTS ARE EXTENDED TO THE CASE WHERE THE SYSTEM HAS AN ARBITRARY COHERENT STRUCTURE WITH EXCHANGEABLE COMPONENTS. ...

IN THIS PAPER,FIRST WE INTRODUCE THE LOG-ODDS (LO) AND LOG-ODDS RATIO (LOR) FUNC- TIONS AND THEIR RELATIONS WITH RELIABILITY CONCEPTS SUCH AS HAZARD AND REVERSED HAZARD RATE. THEN, WE PROPOSED A NEW MEASURE OF SKEWNESS BASED ON LO FUNCTION IN DIS- CRETE AND CONTINUOUS LIFETIME DISTRIBUTIONS AND COMPARE IT WITH PEARSON'S MOMENT COEFFICIENT OF SKEWNESS AND ALSO GROENEVELD-MEEDEN MEASURE OF SKEWNESS VIA SOME EXAMPLES. ALSO SOME RESULTS DUE TO BIVARIATE LOG-ODDS ARE DISCUSSED. ...

REDUNDANCY IS A HIGHLY USED TECHNIQUE TO INCREASE THE SYSTEMS LIFETIMES AND AVAIL- ABILITY. RECENTLY, EMPLOYING STANDBY UNITS IN SYSTEMS HAS RECEIVED GREAT ATTENTION. HERE, PARALLEL SYSTEM OF N UNITS AND TWO-UNIT PARALLEL SYSTEM SUPPORTED BY (N - 2) COLD STANDBYS ARE CONSIDERED WHERE UNITS LIFETIMES ARE ASSUMED TO BE DEPENDENT IN TERMS OF FARLIE-GUMBEL-MORGENSTERN COPULA STRUCTURE. APPLICABLE FORMULAS OF MEAN TIME TO SYSTEM FAILURE ARE GIVEN AND THE IMPACT OF DEPENDENCE PARAMETER ON SYSTEMS LIFETIMES ARE INVESTIGATED. ...

IN THIS PAPER, WE STUDY THE DETERMINATION OF THE WARRANTY PERIOD IN VIEW OF A WAR- RANTY POLICY WHERE THE MANUFACTURE ACCEPT TO MINIMALLY REPAIRED THE FAILURE PRODUCT. TO DO THIS, THE PROBLEM OF PREDICTING THE TIME OF MINIMAL REPAIR BASED ON A PROGRESSIVE TYPE-II CENSORED SAMPLE IS CONSIDERED. WE UTILIZE THE PROPERTY OF PITMAN MEASURE OF CLOSENESS AND PROPOSE A METHOD TO FIND THE CLOSEST PREDICTOR. SINCE, OVER-PREDICATION MAY BE MORE IMPORTANT IN A WARRANTY PROBLEM, ASYMMETRY LOSS IS ALSO CONSIDERED IN THE PROBABILITY OF CLOSENESS. ...

THE CONCEPT OF JOINT SIGNATURES WHICH FIRST DEFINED BY NAVARRO ET AL. [1] ARE USEFUL TOOLS FOR INVESTIGATING THE RELIABILITY OF TWO SYSTEMS WITH SHARED COMPONENTS. WHEN SEVERAL COHERENT SYSTEMS SHARE SOME COMPONENTS AND THE COMPONENTS HAVE INDEPENDENT AND IDENTICALLY DISTRIBUTED (I.I.D.) LIFETIMES, WE OBTAIN A PSEUDO-MIXTURE REPRESENTATION FOR THE JOINT DISTRIBUTION OF THE LIFETIMES OF THE SYSTEMS BASED ON A GENERAL NOTION OF JOINT SIGNATURES. WE PRESENT AN R PROGRAM TO FIND THE MENTIONED JOINT SIGNATURE FOR ANY NUMBER OF SYSTEMS AND COMPONENTS.

THIS PAPER DEAL WITH THE ESTIMATION OF STRESS-STRENGTH RELIABILITY PARAMETER, R = R (C < Y ), WHEN STRESS AND STRENGTH ARE TWO INDEPENDENT STABLE DISTRIBUTIONS. THE MAXIMUM LIKELIHOOD ESTIMATOR OF STABLE DISTRIBUTION STUDIED. FURTHERMORE, WE INVESTI- GATE THE RR;K = R (CR:N1 < YK:N2 ) FOR L_EVY DISTRIBUTION AS A MEMBER OF STABLE FAMILY. USING A MONTE CARLO SIMULATION, THE MSE AND BAYES RISK ESTIMATORS ARE COMPUTED AND COMPARED. ...

AT ANY AGE THE MEAN RESIDUAL LIFE FUNCTION GIVES THE EXPECTED REMAINING LIFE AT THAT AGE. THIS FUNCTION CAN BE USEFUL IN LIFE-TESTING EXPERIMENTS IN BIOLOGICAL AS WELL AS INDUSTRIAL SETTINGS. IN THIS PAPER, WE FIRST PROPOSE A NONPARAMETRIC TEST TO COM- PARE MEAN RESIDUAL LIFE FUNCTIONS BASED ON TWO INDEPENDENT SAMPLES. NEXT, IN ORDER TO ASSESS THE POWER PROPERTIES OF THE PROPOSAL TEST STATISTIC, WE EXAMINE ITS EMPIRICAL POWER PROPERTIES, THROUGH A MONTE CARLO SIMULATION STUDY UNDER DIFFERENT LIFETIME DISTRIBUTIONS.

IDENTIFYING RISK SOURCES OF SURVIVAL DATA ARE GIVEN SPECIAL EMPHASIS IN SURVIVAL ANALYSIS. IDENTIFIABLE RISK FACTORS CAN BE MODELED BY AVAILABLE COVARIATES USING SOME MODELS LIKE COX PROPORTIONAL HAZARDS MODEL. HOWEVER SOME RISK FACTORS ARE OFTEN UNIDENTIFI ABLE OR IMMEASURABLE. THE SPATIAL CORRELATION OF DATA IS ONE OF THESE FACTORS THAT IS RARELY NOTICED. IN THIS PAPER A SPATIAL SURVIVAL MODEL IS INTRODUCED FOR SUCH DATA. A SIMULATION STUDY IS PERFORMED TO SHOW THE HIGH PERFORMANCE OF THE MODEL PARAMETER ESTIMATIONS FOR THE PROPOSED MODEL. RESULTS VALIDATE OUR APPROACH. ...

IN THIS PAPER WE INTRODUCE A NEW AGING CLASS OF LIFE DISTRIBUTIONS WHEN A DEVICE IS OPERATING IN A REALISTIC ENVIRONMENT. WE STUDY THE BEHAVIOR OF SUCH LIFE DISTRIBUTIONS THROUGH THE MEAN RESIDUAL LIFE NOTION, WHEN A DEVICE IS EXPERIENCING NUMBER OF SHOCKS. DUE TO THESE SHOCKS THE LIFETIME OF SUCH DEVICE HAS BECOME SHORTENED OR PROLONGED. THESE TEMPERED EVENTS ARE GOVERNED BY A HOMOGENOUS POISSON PROCESS. A MOMENT INEQUALITY WHICH CHARACTERIZES THIS NEW AGING CLASS, NAMELY RENEWAL INCREASING MEAN RESIDUAL LIFE, IS DERIVED. WE PROPOSE A NEW U-STATISTIC TEST PROCEDURE TO ADDRESS THE PROBLEM OF TESTING EXPONENTIALITY AGAINST SUCH CLASS OF LIFE DISTRIBUTIONS. IT IS SHOWN THAT THE PROPOSED TEST ENJOYS A SUPERIOR POWER FOR SOME COMMONLY USED ALTERNATIVE.

IN MANY PRACTICAL APPLICATIONS IN SYSTEM RELIABILITY, THE ASSUMPTION THAT THE COMPONENT LIFETIMES ARE INDEPENDENT IS NOT VALID AND REALISTIC. IN THIS TALK WE CONSIDER THE E_ECT OF DEPENDENCY BETWEEN SYSTEM COMPONENTS ON MTTF OF THE SYSTEM. FOR EXAMPLE IF WE INCREASE (DECREASE) THE DEGREE OF DEPENDENCY BETWEEN SYSTEM COMPONENTS WETHER THE MTTF OF THE SYSTEM HAS THE SAME BEHAVIOR OR NOT? WE SEE THAT THE ANSWER OF THIS QUESTION DEPENDS ON THE STRUCTURE OF THE SYSTEM (IT ALSO MAY DEPEND ON THE STRUCTURE OF DEPENDENCY BETWEEN SYSTEM COMPONENTS).

IN FORMER LIFETIME PERFORMANCE INDEX CL STUDIES, IT IS USUALLY ASSUME THAT QUALITY CHARACTERISTIC IS THE LIFETIME OF AN ELECTRONIC COMPONENT, ENGINE, CAMERA OR IN SPECIAL CASE LIFETIME OF BUSINESS. IN THIS PAPER WE SUPPOSE THAT THE QUALITY CHARACTERISTIC IS THE LIFETIME OF A SERIES SYSTEM AND UNDER THE ASSUMPTION OF EXPONENTIAL DISTRIBUTION FOR COMPONENT LIFETIME, WE PROVIDE A MAXIMUM LIKELIHOOD ESTIMATOR OF CL AND THEN THIS ESTIMATE USED TO DEVELOP TESTING PROCEDURE OF CL. FINALLY, WE GIVE AN EXAMPLE TO ILLUSTRATE THE USE OF THE TESTING PROCEDURE. ...

SURVIVAL DATA OFTEN COME IN A FORM CALLED "CENSORING". WHEN EXACT SURVIVAL TIMES ARE KNOWN ONLY FOR A PORTION OF THE INDIVIDUALS OR UNITS UNDER STUDY CENSORING OCCURS. IN THIS PAPER, WE CONSIDER A PROGRESSIVE HYBRID CENSORING. THE PROBLEM OF PREDICTING TIMES TO FAILURE OF UNITS CENSORED IN MULTIPLE STAGES OF PROGRESSIVELY HYBRID CENSORED FROM EXPONENTIL DISTRIBUTION IS DISCUSED. THE BEST UNBIASED PREDICTOR (BUP), BEST LINEAR UNBIASED PREDICTOR (BLUP) AND MAXIMUM LIKELIHOOD PREDICTOR ARE DERIVED. ...

IT IS ASSUMED THAT IN LONG TERM STUDIES THE LIFETIMES ARE POSITIVELY (NEGATIVELY) ASSOCIATED RANDOM VARIABLES. UNDER SOME REGULAR CONDITIONS, THE STRONG CONVERGENCE RATES OF KAPLAN-MEIER ESTIMATOR OF MARGINAL DISTRIBUTION FUNCTION F AND CUMULATIVE HAZARD FUNCTION L&NBSP;ARE OBTAINED. IN ORDER TO DEMONSTRATE THE EMPIRICAL PERFORMANCE OF THE RESULTS, SIMULATION STUDIES ARE DONE. ...

IN THIS ARTICLE, WE CONSTRUCTED A GOODNESS-OF-_T TEST STATISTIC BASED ON KULLBACK- LEIBLER INFORMATION FOR EXPONENTIAL DISTRIBUTION BY USING MAXIMUM LIKELIHOOD ESTIMATE OF THE MODEL PARAMETER. A MONTE CARLO SIMULATION IS PERFORMED TO EVALUATE THE POWER OF THE PROPOSED TEST FOR SEVERAL ALTERNATIVES UNDER DI_ERENT SAMPLE SIZES AND PROGRES- SIVE _RST-FAILURE CENSORING SCHEMES. ...

NAIR AND NAIR (1989) SHOWED THAT BIVARIATE MEAN RESIDUAL LIFE FUNCTION CHARACTERIZES THE DISTRIBUTION UNIQUELY. THE SUBJECT OF THIS PAPER IS TO VERIFY HOW CLOSELY THE BIVARIATE QUANTILE RESIDUAL LIFE FUNCTION DETERMINES THE DISTRIBUTION. IT HAS BEEN SHOWN THAT LIKE UNIVARIATE CASE, TWO SUITABLE BIVARIATE QUANTILE RESIDUAL LIFE CAN CHARACTERIZE THE UNDERLYING DISTRIBUTION UNIQUELY. ...

USING THE REPAIR ALERT MODEL, THIS PAPER PROPOSES A PROBABILISTIC MODEL FOR THE MAINTENANCE SCHEDULING OF PERIODICALLY INSPECTED SYSTEMS WHOSE STATE IS DESCRIBED BY A MEAN RESIDUAL LIFETIME (MRL) PROCESS. ATTENTION IS RESTRICTED TO THE PERIODIC INSPEC- TION AND PERFECT REPAIR, BUT THE MODEL PROVIDES A FRAMEWORK FOR FURTHER DEVELOPMENTS.

THIS PAPER IS CONCERNED WITH RELIABILITY MODELING OF MULTI-STATE K-OUT-OF-N SYSTEMS CONSISTING OF MULTI-STATE COMPONENTS. IT IS ALSO ASSUMED THAT EACH COMPONENT OF THE SYSTEM HAS AN INTEGER-VALUED RANDOM WEIGHT (CAPACITY). A RECURSIVE ALGORITHM IS PRESENTED FOR RELIABILITY EVALUATION OF THIS MODEL. SOME ILLUSTRATIVE EXAMPLES ARE ALSO PROVIDED. ...

IN THIS PAPER, WE STUDY THE RESIDUAL LIFETIME OF COHERENT SYSTEM WITH POSSIBLY DE- PENDENT IDENTICALLY DISTRIBUTED COMPONENT LIFETIMES. THESE RESULTS ARE BASED ON THE REPRESENTATION OF SYSTEM RELIABILITY FUNCTION AS A DISTORTED FUNCTION OF COMMON RELIA BILITY FUNCTION OF COMPONENTS. ...

IN SURVIVAL ANALYSIS AND RELIABILITY THEORY, A FUNDAMENTAL PROBLEM IS THE STUDY OF LIFETIME PROPERTIES OF A LIVE ORGANISM OR SYSTEM. IN THIS REGARD, THERE HAVE BEEN CON- SIDERED AND STUDIED SEVERAL MODELS BASED ON DIFFERENT CONCEPTS OF AGING SUCH AS HAZARD RATE AND MEAN RESIDUAL LIFE. IN THIS PAPER, WE CONSIDER AN ADDITIVE-MULTIPLICATIVE HAZARD MODEL (AMHM) AND STUDY SOME OF RELIABILITY AND AGING PROPERTIES OF THE PROPOSED MODEL. WE THEN SPECIFY THE BIVARIATE MODELS WHOSE CONDITIONALS SATISFY AMHM. SEV- ERAL PROPERTIES OF THE PROPOSED BIVARIATE MODEL ARE INVESTIGATED. ...