摘要:

Often, second-order response surface designs are chosen on the basis of a single-valued criterion such as D- or G-optimality. While such criteria provide a useful basis for selecting designs, they often fail to convey the true nature of the design's support of the fitted model in terms of prediction properties over a region of interest. As an alternative to a single-valued criterion, we propose variance dispersion graphs to compare various second-order response surface designs. This graphical procedure is used to examine the relative strengths and weaknesses of such popular designs as the central composite, Box-Behnken, and small composite. Areas in the region of interest where prediction is relatively good and relatively poor are discussed, and designs which have good overall performance are highlighted. A summary comparison of such saturates or near-saturates designs as the hybrid, Box-Draper, and Notz designs is given together with recommendations concerning the proper choice among these designs. Finally, we show how the use of the D-optimality criterion can lead to misleading results when the user is truly interested in response surface prediction.

ISSN:0022-4065    

DOI:10.1080/00224065.1992.11979368

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Most applications of the exponentially weighted moving average (EWMA) for process monitoring have concentrated on the problem of detecting shifts in the mean level of a process. Perhaps more important is the problem of detecting increases in process variability, which can also have a major impact on product quality. In this paper we propose using an EWMA based on the log transformation of the sample variance. Properties of this EWMA are given and an optimal design strategy is presented. It is shown that the EWMA is superior to the usual range chart or s2chart in terms of its ability to quickly detect small increases in the standard deviation of a normal process.

ISSN:0022-4065    

DOI:10.1080/00224065.1992.11979369

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

A paint coating process for which there is little information known about the relationship between the production variables and the output variables was investigated. The goal was to determine the optimum process settings to achieve the target value for the response, coating thickness. Three planned experiments of eight runs each were carried out, the first with four replicates and the other two with two replicates. The observed data were analyzed using a multiple linear regression. Four input factors appeared to be significant and were used to set the production levels in such a way that the desired coating thickness was achieved.

ISSN:0022-4065    

DOI:10.1080/00224065.1992.11979370

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

This paper describes two case studies involving an optical emission spectrometer used for measuring the chemical composition of steel. The first case study describes the design and analysis of an experiment for estimating some key components of variance in spectrometer measurements. The results of this experiment motivated several subsequent investigations, including the second case study: an investigation into causes of instability of the spectrometer.

ISSN:0022-4065    

DOI:10.1080/00224065.1992.11979371

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Cumulative sum (CUSUM) control charts are very effective in detecting special causes. In designing a CUSUM chart, it is important to know the average run lengths (ARL's) corresponding to various possible choices of the mask parameters. This paper provides a relatively simple yet very accurate (typically within 3%) approximation for the ARL of a CUSUM chart, both when the process is in control and when it is out of control. Examples are given showing how the approximation can be used to evaluate the ARL for specific parameter values, to find values that give a desired ARL, and to evaluate the out-of-control ARL's of location and scale CUSUM charts.

ISSN:0022-4065    

DOI:10.1080/00224065.1992.11979372

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

A program is presented that generates a table of ARL's for a one-sided EWMA control chart on a process standard deviation. The combination of smoothing parameterλand constant upper control limit multiplierKthat produces the minimum ARL for a specified increase in the standard deviation can be determined from that table.

ISSN:0022-4065    

DOI:10.1080/00224065.1992.11979373

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0022-4065    

DOI:10.1080/00224065.1992.11979374

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0022-4065    

DOI:10.1080/00224065.1992.11979375

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0022-4065    

DOI:10.1080/00224065.1992.11979376

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0022-4065    

DOI:10.1080/00224065.1992.11979377

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor