Phase II Monitoring of MA (1) Linear Profiles
نویسندگان
چکیده
Recently, monitoring quality of a process or product that is characterized by a function or profile is becoming more popular. Many applications are shown for profile monitoring. Most existing control schemes, which have been suggested for profile monitoring in the literatures, consider the independence assumption of observation within profiles. However, in certain situation, this assumption can be violated. Violation of the independence assumption can affect the performance of most control charts strongly. There are some investigations to monitor auto correlated profiles in recent years. In this paper, we consider a simple linear profile where the observations within profiles are assumed to be correlated according to an MA(1) structure. We show the effect of correlation on the performance of monitoring process and use a transformation to eliminate the effect of correlation within profiles. A method is discussed to monitor the transformed profiles. The performance of the proposed method is evaluated using average run length (ARL) criterion. Results indicate satisfactory performance for the proposed method.
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