摘要:

Variations in manufacturing processes are expected to fluctuate around a constant level called the process mean. This article is concerned with the development of a control chart that detects cycles in the process mean. The new control chart, the spectral control chart, is based on the periodogram. The value plotted at each point in time is the ratio of the largest periodogram ordinate to the average of all ordinates. When an observation falls above the prescribed control limit, an out-of-control signal is given. The spectral control chart is compared with the Shewhart and geometric moving average charts. Data obtained from Monte Carlo simulations show that the spectral control chart is superior for detecting cyclic variations but that it is not effective for detecting shifts in the process mean. Thus the spectral control chart should be used along with existing control charts so that both shifts and cycles in the process mean can be detected.

ISSN:0040-1706    

DOI:10.1080/00401706.1988.10488323

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Any planar displacement of a rigid body can be uniquely characterized as a rotation about some fixed axis through a certain angle. These same rotational parameters can also describe the relative motion of two joint components and have been used to describe the rotational behavior of human body joints. This article derives estimates of these parameters and their standard errors, based on geometric arguments for the coordinates of markers observed during the rotation. This in turn identifies optimal placements of the experimental markers, which maximize the precision of the estimated center of rotation and the angle of rotation. This is the first statistical treatment of this problem. Previous approaches used deterministic error structures.

ISSN:0040-1706    

DOI:10.1080/00401706.1988.10488324

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

One approach to testing the goodness of fit of a completely specified continuous distribution when only a subset of the ordered sample is available is to transform that subset into a complete uniform ordered sample of smaller size. After this, any of the classical tests for uniformity may be used. Two systematic procedures for transforming a subset of the ordered sample are studied, and they are illustrated when the subset results from single censoring of the data on the left or right or at both extremes. The procedures are derived from Rosenblatt's transformation and are shown to coincide for Type II singly censored data at one extreme with a procedure proposed earlier by Michael and Schucany (1979). A Monte Carlo power study was conducted to analyze the relative merits of the procedures followed by the Anderson-Darling AZ test for uniformity for some types of censoring.

ISSN:0040-1706    

DOI:10.1080/00401706.1988.10488325

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This article presents a procedure for computing the renewal function, the renewal density, the integral of the renewal function, and the variance function of phase-type renewal processes. The procedure hinges on the computation of the state probability vector of a continuous-time Markov chain. This is accomplished by using a randomization approach that is simple, efficient, and numerically stable and does not require numerical integration. I discuss approximating arbitrary interrenewal distributions by phase-type distributions so that the procedure can be used to approximate renewal and related functions.

ISSN:0040-1706    

DOI:10.1080/00401706.1988.10488326

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A measure that quantifies the amount of rotatability in a given response-surface design is introduced in this article. The measure, which is expressible as a percentage, takes the value 100 if and only if the design is rotatable. One of the main advantages of this measure is that it can be used to “repair” a nonrotatable design by the addition of experimental runs that maximize the percent rotatability over a spherical region of interest. Four numerical examples are given to illustrate the applications of this measure.

ISSN:0040-1706    

DOI:10.1080/00401706.1988.10488327

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

An index of rotatability is suggested that will enable the experimenter to obtain an immediate appreciation of the overall shape of specified variance contours for symmetrical second-order designs. Values of the index are tabulated for the central composite designs for two to eight factors. Three designs of Roquemore (1976) are assessed via the index. Comparisons are made with an entirely different index suggested by Khuri (1988). It is concluded that both indexes are useful and sensibly consistent.

ISSN:0040-1706    

DOI:10.1080/00401706.1988.10488328

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0040-1706    

DOI:10.1080/00401706.1988.10488329

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0040-1706    

DOI:10.1080/00401706.1988.10488330

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0040-1706    

DOI:10.1080/00401706.1988.10488331

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0040-1706    

DOI:10.1080/00401706.1988.10488332

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor