|
Contact
|
Nien-Fan
Zhang
Statistical Engineering
Division
Information Technology
Laboratory
301-975-2842
nien-fan.zhang@nist.gov
|
|
Impetus/How Project Began
|
Process monitoring is very important for industries. Statistical
methodologies have been used to monitor various production process
successfully. The majority of statistical process monitoring
techniques assume that the process data are free of correlation.
However, this assumption is frequently invalid in many manufacturing
processes and other processes. For example, chemical process data
and internet traffic data are correlated or self dependent. Under
such conditions, the traditional statistical monitoring methodologies
are not effective. The impetus of this project is to develop new
statistical methodologies to apply to the self dependent data.
|
|
Objective(s)
|
Nothing to report at this time.
|
|
FTE
|
The objectives of this project are:
- to provide new statistical measures and techniques for
process monitoring and control for manufacturing industries,
and
- to perform research in the applications of these techniques
to additional areas with one example being the monitoring of
internet traffic.
|
Timeline/
Milestones
|
The timelines and milestones for this project are:
- FY94 - Publish the first paper on dynamic processes in
Technometrics.
- FY97 - Publish a paper on detection capability of residual
control charts and publish a paper on autocorrelation analysis
of linear transfer function models.
- FY98 - Publish a paper on process capability indices for
autocorrelated data. Publish a paper on control chart for
stationary process data in Technometrics.
- FY99 - Make comparisons among the control charts for
autocorrelated data.
- FY00 - Publish a paper on the comparisons of control charts
for autocorrelated data. Propose to use generalized moving
averages of stationary process data to reduce process
autocorrelations.
|
|
NIST Involvement
|
The following NIST staff are involved in this project:
- Nien-Fan Zhang (Division 898, ITL),
|
|
What Work Has ITL Done
|
ITL has performed the following work for this project.
- Have developed new statistical techniques for self dependent
process data.
- Statistical process control charts and process capability
indices and other techniques for self dependent data have
been proposed.
- Eight papers have been published in various statistical
and mathematical journals.
|
|
What Work Has Been Done By Collaborators
|
Some statisticians and engineers of Shell Oil Company were involved
at the early stage of this project.
|
|
What Developments Have Occurred and How Has the Project Changed
|
Nothing to report at this time.
|
|
Publications or Artifacts
|
This project has generated the following publications.
- Zhang, N. F. (2000) " Statistical Control Charts for
Monitoring the Mean of a Stationary Process," to appear in
Journal of Statistical Computation and Simulation.
- Zhang, N. F. (1999) "Statistical control for autocorrelated
data," Proceedings of EUROPT Series: Process and Equipment
Control in Microelectronic Manufacturing," Vol. 3742, 65-70.
- Zhang, N. F. (1998) "Comparisons of Control Charts for
Autocorrelated Data," 1998 proceedings of the Section on
Quality and Productivity of American Statistical Association,
8-12.
- Zhang, N. F. (1998), "Estimating Process Capability Indices
for Autocorrelated Data," Journal of Applied Statistics,
25(4), 559-574.
- Zhang, N. F. (1998), "A Statistical Control Chart for
Stationary Process Data," Technometrics, 40(1), 24-38.
- Zhang, N. F. (1997), "Detection Capability of Residual
Control Chart for Stationary Process Data,"
Journal of Applied Statistics, 24(4), 475-492.
- Zhang, N. F. (1997), "Autocorrelation Analysis of Some Linear
Transfer Function Models and its Applications in the Dynamic
Process System," Lectures in Applied Mathematics, 33,
385-399, American Mathematical Society.
- Zhang, N. F and J. P. Pollard (1994), "Analysis of
Autocorrelations in Dynamic Processes," Technometrics,
36, 354-368.
|
|
How Industries Have Benefited From NIST's Work
|
The methodologies have been published in several mathematical and
statistical journals and have been presented to mathematical and
applied statistics societies. The responses are encouraging.
Some methodology has been implemented in industry.
|
|
Acknowledgements of the ITL's Effort
|
Nothing to report at this time.
|
|
Future Related Activities
|
Nothing to report at this time.
|
|
Additional Information
|
Additional information is available at:
|
