Research Interests

Peihua Qiu's Research on Dynamic Screening Systems


In our daily life, we often need to identify individuals whose longitudinal behavior is different from the behavior of those well-functioning individuals, so that some unpleasant consequences can be avoided. For instance, if the observed values of certain cardiovascular disease risk factors of a person are significantly worse than the values of a typical healthy person with similar age and other comparable confounding risk factors, then some medical treatments should be taken to avoid the occurance of stroke and other deadly cardiovascular diseases. In many such applications, observations of a given individual are obtained sequentially, and it is desirable to have a screening system to give a signal of irregular behavior as soon as possible, after that individual’s longitudinal behavior starts to deviate from the regular behavior, so that some adjustments or interventions can be made in a timely manner. This problem is called dynamic screening (DS) problem in our research. It has been explained in Qiu and Xiang (2014) that the DS problem cannot be solved satisfactorily by the conventional longitudinal data analysis (LDA) or statistical process control (SPC) methodologies. In Qiu and Xiang (2014), we proposed a new method, called dynamic screening system (DySS) in cases when the longitudinal behavior is univariate, which combines the strengths of LDA and SPC and provides a satisfactory solution to the DS problem. A multivariate version is proposed in Qiu and Xiang (2015). DySS is a new research area, and many research problems are still open and need much future research effort.

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