DETECTING INFORMATION IN GAS SENSOR RESPONSES USING ANALYSIS OF VARIANCE

This article describes how Analysis of Variance may be used to select those regions of the curves generated by a gas sensor array which cont ain the most discriminant information for a particular application. Th e Analysis of Variance is performed on each point of the signals gener ated by the sensor array for a particular set of samples. The Group Va riances and the Residual Variances are plotted as functions of their p osition in the signal. Regions of the signals that vary systematically from one group of samples to another will have high Group Variance va lues and low and randomly distributed Residual Variance values. This m ethod has shown for a particular set of products for cats analysed wit h a thirty two polymer sensor array, that the most discriminant inform ation is located at the end of the curves. It has also shown an absenc e of discrimination between standard and tainted pig fat samples with this sensor array. The advantage of this method is that it can be used on almost any sort of raw signal as a pre-analysis step in order to k now whether it is worthwhile going on to more fastidious and time cons uming signal analysis procedures.