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dc.contributor.authorHughes, Christopher Scotten_US
dc.date.accessioned2014-03-14T21:10:33Z
dc.date.available2014-03-14T21:10:33Z
dc.date.issued1999-04-13en_US
dc.identifier.otheretd-041999-130738en_US
dc.identifier.urihttp://hdl.handle.net/10919/37643
dc.description.abstractIndustrial processes are subject to changes that can adversely affect product quality. A change in the process that increases the variability of the output of the process causes the output to be less uniform and increases the probability that individual items will not meet specifications. Statistical control charts for monitoring process variance can be used to detect an increase in the variability of the output of a process so that the situation can be repaired and product uniformity restored. Control charts that increase the sampling rate when there is evidence the variance has changed gather information more quickly and detect changes in the variance more quickly (on average) than fixed sampling rate procedures. Several variable sampling rate procedures for detecting increases in the process variance will be developed and compared with fixed sampling rate methods. A control chart for the variance is usually used with a separate control chart for the mean so that changes in the average level of the process and the variability of the process can both be detected. A simple method for applying variable sampling rate techniques to dual monitoring of mean and variance will be developed. This control chart procedure increases the sampling rate when there is evidence the mean or variance has changed so that changes in either parameter that will negatively impact product quality will be detected quickly.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartetd.pdfen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjectShewhart charten_US
dc.subjectintegral equationen_US
dc.subjectMarkov chainen_US
dc.subjectCUSUM charten_US
dc.subjectEWMA charten_US
dc.titleVariable Sampling Rate Control Charts for Monitoring Process Varianceen_US
dc.typeDissertationen_US
dc.contributor.departmentStatisticsen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
dc.contributor.committeememberYe, Keyingen_US
dc.contributor.committeememberCoakley, Clint W.en_US
dc.contributor.committeememberFoutz, Roberten_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-041999-130738/en_US
dc.contributor.committeecochairArnold, Jesse C.en_US
dc.contributor.committeecochairReynolds, Marion R. Jr.en_US
dc.date.sdate1999-04-19en_US
dc.date.rdate2000-05-20
dc.date.adate1999-05-20en_US


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