A Robust Smoothing Approach to Statistical Process Control

Abstract

It has previously been shown that smoothing algorithms can provide the basis for methods to detect nuclear material losses and moreover can also provide a general approach to industrial statistical process control. The present paper extends this result by showing that a set of robust smoothers also produces methods that can be used in statistical process control. Further, it is shown that these smoothers are somewhat more sensitive to out of control points than those methods previously studied. The methods are successfully illustrated on chemical process data.

Proposed Capability Indices Based on Robust Estimation Compared with Classical Capability Indices

“…Identifying control limits for control charts requires accurate estimations of process parameters, such as location, scale, etc. [4] The authors of Grznar et al [5] and Mahmood [6] offer a methodology for outlier detection based on smoothing techniques. Different techniques for obtaining confidence intervals for polymerase chain reaction based on reliable estimations of non-normal data are discussed in Kocherlakota and Kocherlakota.…”

Topological Organic Chemistry. 12. Whole-Molecule Schultz Topological Indices of Alkanes

“…Interestingly, this is the same general technique used to clarify and enhance digitally transmitted pictures, such as of astronomical objects. More distantly related instances of linear filtration or smoothing, for example, are described and reviewed in recent work by Grznar et al 11,12 COMPUTATIONS Molecular graphs, hydrogen-suppressed and with the interatomic carbon-carbon edge count set at unity, were derived from the alkane series, ethane through the octane isomers, listed in Table 2. The IUPAC system of numbering was used, as displayed in Figure la, which pictures a modified stem-and-leaf graph of 2-methylbutane.…”

“…Interestingly, this is the same general technique used to clarify and enhance digitally transmitted pictures, such as of astronomical objects. More distantly related instances of linear filtration or smoothing, for example, are described and reviewed in recent work by Grznar et al , …”