摘要:

Genichi Taguchi has emphasized the use of designed experiments in several novel and important applications. In this paper we focus on the use of statistical experimental designs in designingproducts to be robust to environmental conditions. The engineering concept of robust product design is very important because it is frequently impossible or prohibitively expensive to control or eliminate variation resulting from environmental conditions. Robust product design enablesthe experimenter to discover how to modify the design of the product to minimize the effect dueto variation from environmental sources. In experiments of this kind, Taguchi's total experimental arrangement consists of a cross-product of two experimental designs:an inner array containing the design factors and an outer array containing the environmental factors. Except in situations where both these arrays are small, this arrangement may involve a prohibitively large amount of experimental work. One of the objectives of this paper is to show how this amount of work can be reduced. In this paper we investigate the applicability of split-plot designs for thisparticular experimental situation. Consideration of the efficiency of split-plot designs and anexamination of several variants of split-plot designs indicates that experiments conductedin a split-plot mode can be of tremendous value in robust product design since they not only enable the contrasts of interest to be estimated efficiently but also the experiments can be considerably easier to conduct than the designs proposed by Taguchi.

ISSN:0266-4763    

DOI:10.1080/02664769200000001

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

Lattice sampling designs have been developed to provide efficient estimates of ‘counts' of river users and characteristics of use to determine the recreational value of rivers.

ISSN:0266-4763    

DOI:10.1080/02664769200000002

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

Many medical and biological studies involve response in the form of Poisson counts which can bemodelled using explanatory variables which also arise from count data. If the explanatory variables are observable without error (also as Poisson counts) we have a generalized linear model with a logarithmic link function and Poisson error structure. If,however, some of the explanatory variables are not directly observable, but arise with superimposed errors (again of Poisson form), the model is of a new type:a generalised linear functional Poisson model. In this paper,maximum likelihood estimates of the parameters of this model are determined along with the information matrix which (on noting its particular patterned form) is amenable to inversion in explicit form. Methods are proposed of an iterative type for computing estimates of the parameters and of their variational properties (e.g. standard errors) for this model, which also has application in other fields such as road traffic studies.

ISSN:0266-4763    

DOI:10.1080/02664769200000003

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

This paper is concerned with prediction in the spatial linear model using the maximum likelihood estimation of parameters in this model. In particular, we give some properties of predictors obtained on substituting the maximum likelihood estimators of model parameters into the form of the best-in the sense of minimum mean square prediction error-predictor. Such predictors are not optimal but we show them to be asymptotically equivalent to the optimum. We discuss practical aspects of this work and conclude by considering the connection with other areas.

ISSN:0266-4763    

DOI:10.1080/02664769200000004

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

The underlying theory upon which many statistical tests are based, assumes that the variables sampled are continuous. However, the data are often subject to rounding. Here we consider the effect of rounding on the significance level and power of the F test in the one-way analysis of variance with fixed effects, with respect to the degree of precision of recorded data, sample size and normality of the population. Even for coarse rounding the effects are small.

ISSN:0266-4763    

DOI:10.1080/02664769200000005

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

An adaptation from Cuscore control charts for normal distributions to the problem of monitoring the rate of occurrence of a rare event is considered. The presented scheme defines an alarm in terms of the sum of ‘scored distances' between successive events of interest. A procedure is given for using this scheme in an ‘optimal’ manner which minimizes the out of control expected delay for a given rate of false alarms. Comparisons over a number of examples, after matching the rate of false alarms, show that the present technique is more efficient than those of Shewhart and Sets, and also than Cusum under conditions of practical relevance.

ISSN:0266-4763    

DOI:10.1080/02664769200000006

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

In this paper the indicator approach in spatial data analysis is presented for the determination of probability distributions to characterize the uncertainty about any unknown value. Such an analysis is non-parametric and is done independently of the estimate retained. These distributions are given through a series of quantile estimates and are not related to any particular prior model or shape. Moreover, determination of these distributions accounts for the data configuration and data values. An application is discussed. Moreover, some properties related to the Gaussian model are presented.

ISSN:0266-4763    

DOI:10.1080/02664769200000007

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

summary In this paper we derive the predictive density function of a future observation under the assumption of Edgeworth-type non-normal prior distribution for the unknown mean of a normal population. Fixed size single sample and sequential sampling inspection plans, in a decisive prediction framework, are examined for their sensitivity to departures from normality of the prior distribution. Numerical illustrations indicate that the decision to market the remaining items of a given lot for a fixed size plan may be sensitive to the presence of skewness or kurtosis in the prior distribution. However, Bayes'decision based on the sequential plan may not change though expected gains may change with variation in the non-normality of the prior distribution.

ISSN:0266-4763    

DOI:10.1080/02664769200000008

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

Results are presented for the probability that a contaminated observation in a normal sample isan outlier. Univariate samples with mean-shift or variance inflation contamination were considered. Multivariate samples with inflation of the covariance matrix in which an outlier is the observation with minimum conditional predictive ordinate were also studied. All the results were obtained by numerical integration or simulation.

ISSN:0266-4763    

DOI:10.1080/02664769200000009

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

We investigate the usefulness of sample autocorrelations and partial autocorrelations as model specification tools when the observed time series is contaminated by an outlier. The results indicate that the specification power of these statistics could be significantly jeopardized by an additive outlier. On the other hand, an innovational outlier seems to cause no harm to them.

ISSN:0266-4763    

DOI:10.1080/02664769200000010

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor