摘要:

It is more than a decade since Genichi Taguchi's ideas on quality improvement were inrroduced in the United States. His parameter-design approach for reducing variation in products and processes has generated a great deal of interest among both quality practitioners and statisticians. The statistical techniques used by Taguchi to implement parameter design have been the subject of much debate, however, and there has been considerable research aimed at integrating the parameter-design principles with well-established statistical techniques. On the other hand, Taguchi and his colleagues feel that these research efforts by statisticians are misguided and reflect a lack of understanding of the engineering principles underlying Taguchi's methodology. This panel discussion provides a forum for atechnicaldiscussion of these diverse views. A group of practitioners and researchers discuss the role of parameter design and Taguchi's methodology for implementing it. The topics covered include the importance of variation reduction, the use of noise factors, the role of interactions, selection of quality characteristics, signal-to-noise ratios, experimental strategy, dynamic systems, and applications. The discussion also provides an up-to-date overview of recent research on alternative methods of design and analysis.

ISSN:0040-1706    

DOI:10.1080/00401706.1992.10484904

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In planning a fractional factorial experiment prior knowledge may suggest that some interactions are potentially important and should therefore be estimated free of the main effects. In this article, we propose a graph-aided method to solve this problem for two-level experiments. First, we choose the defining relations for a 2n–kdesign according to a goodness criterion such as the minimum aberration criterion. Then we construct all of the nonisomorphic graphs that represent the solutions to the problem of simultaneous estimation of main effects and two-factor interactions for the given defining relations. In each graph a vertex represents a factor and an edge represents the interaction between the two factors. For the experiment planner, the job is simple: Draw a graph representing the specified interactions and compare it with the list of graphs obtained previously. Our approach is a substantial improvement over Taguchi's linear graphs.

ISSN:0040-1706    

DOI:10.1080/00401706.1992.10484905

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The problem of determining one-sided tolerance limits or, equivalently, one-sided confidence limits on a quantile of a normal population with variance σ2= σ2b+ σ2bis considered in this article. The tolerance limits are obtained using data from a one-way balanced randomeffects sample from this population. Two procedures are introduced—a simple approximate method based on an asymptotic expansion and a computer-intensive procedure that provides very nearly the nominal confidence in the presence of the nuisance variance-component ratio. For the computer-intensive procedure, tables are provided that eliminate the need for most of the computation for some important situations. Tolerance limits for strength are routinely used in structural design. Material strength, particularly for composite materials, often exhibits considerable between-batch variability. A tolerance limit that provides nearly the nominal confidence is usually preferable to a conservative limit, since a conservative tolerance limit underestimates the capability of the material. An aircraft-industry application to determining tolerance limits for composite material properties in the presence of between-batch variability is discussed.

ISSN:0040-1706    

DOI:10.1080/00401706.1992.10484906

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We suggest new plotting methods for residual analysis in errors-in-variables regression. The standard residuals analyses are based on the methods of Miller and Fuller and are appropriate when the errors in the regression and the measurement error are symmetrically distributed. By “appropriate,” we mean that in large samples the plots will not falsely identify a nonexistent pattern of heteroscedasticity or nonlinearity. The standard methods are not appropriate in this sense for skewed error distributions. Our methods require replication of the error-prone predictors, but they are appropriate for both symmetric and skewed error distributions. Besides residual plots, we also construct hypothesis tests for heteroscedasticity. In terms of power for detecting heteroscedasticity, we show that the standard plot is more efficient when the residuals are normally distributed, although it does not achieve its nominal level for skewed error distributions. Simulations are used to illustrate the results. We also consider the case that measurement error in the response is correlated with the measurement error in the predictors, suggesting new residual plots in this setting. The article also contains a short summary of plotting techniques for detecting heteroscedasticity in regression.

ISSN:0040-1706    

DOI:10.1080/00401706.1992.10484907

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We apply the local-influence method of Lawrance to assess the effect of the case-weights perturbation on the transformation-power estimator in the Box-Cox regression model. We show that this method is the same as the local-influence method proposed by Cook. Furthermore, the difference in local-influence diagnostics between the case-weights perturbation and the constant-variances perturbation is examined and the relationship between the localinfluence diagnostic and the deletion diagnostic is studied. An example is presented to illustrate local-influence diagnostics.

ISSN:0040-1706    

DOI:10.1080/00401706.1992.10484908

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Suppose a set ofTlots has been subject to zero-defect acceptance sampling with rectification. A lot is accepted if there are no nonconforming units in a sample; otherwise there is 100% inspection of the lot and all nonconforming units are replaced with conforming ones. We introduce an estimator for the number of nonconformances that remain in those lots, using the data observed during acceptance sampling, including the rectification procedure. The estimator proposed is similar to a Horvitz-Thompson estimator in that it weights the number of detected nonconformances in a lot by the inverse of its detection probability. The mean squared error of this estimator is compared with several alternatives. The proposed estimator was found to perform well under a variety of models for the nonconformance process. Confidence interval procedures are given for the proposed estimator. A simulation study shows that coverage is less than the nominal level for few lots and small sample sizes. We observe that the coverage is improved by the use of a transformation.

ISSN:0040-1706    

DOI:10.1080/00401706.1992.10484909

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This article presents an upper confidence bound for a measure of reliability/maintainability of a series system in which component repair is assumed to restore the system to its original status. Under exponentiality of component-repair time and survival time distributions, the measureMis the ratio of expected system-repair time to expected system-survival time. Moreover, under this exponentiality assumption, the bound is uniformly minimum among all bounds of specified level that are nondecreasing functions of the maximum likelihood estimator ofM. As a matter of practical interest, the measureMhas been incorporated into Military Standard MIL-STD-470B and is an official statistic of the Air Force Reliability Maintainability Information System.

ISSN:0040-1706    

DOI:10.1080/00401706.1992.10484910

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0040-1706    

DOI:10.1080/00401706.1992.10484911

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0040-1706    

DOI:10.1080/00401706.1992.10484912

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0040-1706    

DOI:10.1080/00401706.1992.10484913

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor