Daniel W. Apley
Associate Professor

Dept. of Industrial Engineering and Management Sciences

McCormick School of Engineering and Applied Science

Northwestern University

2145 Sheridan Road

Evanston IL 60208-3119

office: Technological Institute C150
phone: (847) 491-2397
fax: (847) 491-8005
email: apley[at]northwestern.edu

 


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Brief Bio

Research and Teaching Overview

Publications

Detailed Vitae (pdf)

BRIEF BIO

I am an Associate Professor of Industrial Engineering and Management Sciences at Northwestern University, Evanston, IL. I obtained B.S., M.S., and Ph.D. degrees in Mechanical Engineering and an M.S. degree in Electrical Engineering from the University of Michigan. Prior to joining Northwestern University in 2003, I served on the faculty of Texas A&M University for five years. My research interests lie at the interface of engineering modeling, statistical analysis, and data mining, with applications that include quantitative six sigma process improvement and manufacturing variation reduction. Much of my work in these application areas is geared towards processes in which one is inundated with data, in particular those that are pervaded by measurement and automation technology. I received an NSF CAREER award for my research and teaching in this area in 2001. I am a past chair of the Quality, Statistics & Reliability Section of INFORMS, a past Director of the Manufacturing and Design Engineering Program at Northwestern, and I currently serve as an Associate Editor for Technometrics and on the Editorial Board of the Journal of Quality Technology.

RESEARCH AND TEACHING OVERVIEW

My broad areas of research and teaching interest are:

·         Engineering statistics

·         Data mining and statistical learning

·         Statistical quality control and six sigma variation reduction

·         Manufacturing process diagnosis and automatic control

Much of my research addresses the pervasive problem of how to transform large amounts of data into useful information, solutions to which are often referred to generically as "data mining". One data mining application domain in which I am particularly interested is manufacturing process improvement. Extracting information from manufacturing process data often involves using engineering models, knowledge and information within a statistical framework. I am also interested in representing and quantifying model uncertainty in model-based methods, for the purpose of creating tools that are effective and robust in complex, difficult-to-model processes.

In typical six sigma problems on which I work, a manufacturer might measure thousands of different variables related to product quality and the state of each process, including machine signatures and other functional data. These high-dimensional data are collected over time and recorded in massive databases.  Often, the research objective is to develop a methodology for discovering and visualizing pieces of information in these large databases that help process engineers systematically identify and eliminate root causes of variation, inconsistency, and poor quality. My research in this area boils down to developing six sigma tools that are designed for modern manufacturing processes in which one is inundated with high-volume, high-dimensional data. My recent research projects have developed and applied these tools to automobile manufacturing, electronics assembly, aerospace structure manufacturing, and integrated circuit fabrication.

I also conduct research on the interface between statistical and engineering modeling and data mining in other application domains, such as business intelligence and product design optimization. Recent projects in these areas include developing predictive models for strategic management of credit risk, based on large-scale customer databases; and developing Bayesian statistical methods for design optimization with deterministic computer simulations, such as finite element simulation of vehicle crashworthiness, sheet metal stamping processes, etc.   

At Northwestern, I teach undergraduate courses in Statistical Methods for Quality Improvement (IEMS 305), Introductory Statistics (IEMS 303), and Intermediate Statistics (IEMS 304), the latter course being an introduction to the statistical tools of data mining. I also teach graduate courses in Quality Engineering (IEMS 428) and Engineering Applications of Data Mining (IEMS 490).

PUBLICATIONS

Shan, X. and Apley, D. W., "Blind Identification of Manufacturing Variation Patterns by Combining Source Separation Criteria," Technometrics, to appear.

Apley, D. W. and Lee, H. C., "Robustness Comparison of Exponentially Weighted Moving Average Charts on Autocorrelated Data and on Residuals," Journal of Quality Technology, to appear.

Jiang, W., Shu, L., and Apley, D. W. "Adaptive CUSUM Procedures with EWMA-based Shift Estimators," IIE Transactions, to appear.

Chin, C. H. and Apley, D. W., "Performance and Robustness of Control Charting Methods for Autocorrelated Data," Journal of the Korean Institute of Industrial Engineers, 34(2), pp. 122—139, June, 2008.

Ding, Y. and Apley, D. W., "Guidelines for Placing Additional Sensors to Improve Variation Diagnosis in Assembly Processes," International Journal of Production Research, 45(23), pp. 5485-5507, December, 2007.

Xiong, Y., Chen, W., Apley, D. W., and Ding, X. "A Nonstationary Covariance Based Kriging Method for Metamodeling in Engineering Design," International Journal for Numerical Methods in Engineering, 71(6), pp. 733-756, August, 2007.

Apley, D. W., and Zhang, F., "Identifying and Visualizing Nonlinear Variation Patterns in Multivariate Manufacturing Data", IIE Transactions, 39(6), pp. 691-701, June, 2007.

Apley, D. W. and Chin, C. H., "An Optimal Filter Design Approach to Statistical Process Control," Journal of Quality Technology, 39(2), pp. 93-117, April, 2007.

Chin, C. H. and Apley, D. W. "Optimal Design of Second-Order Linear Filters for Control Charting," Technometrics, 48(3), pp. 337-348, August, 2006.

Apley, D. W., Liu, J. and Chen, W. "Understanding the Effects of Model Uncertainty in Robust Design With Computer Experiments," ASME Journal of Mechanical Design, 128(4), pp. 945-958, July, 2006.

Apley, D. W. and Ding, Y., "A Characterization of Diagnosability Conditions for Variance Components Analysis in Assembly Operations," IEEE Transactions on Automation Science and Engineering, 2(2), pp. 101-110, April, 2005.

Lee, H. Y. and Apley, D. W. "Diagnosing Manufacturing Variation Using Second-Order and Fourth-Order Statistics," International Journal of Flexible Manufacturing Systems, 16, pp. 45-64, 2004.

Apley, D. W. and Kim, J.B., "Cautious Control of Industrial Process Variability with Uncertain Input and Disturbance Model Parameters," Technometrics, 46(2), pp. 188-199, 2004.

Ding, Y., Gupta, A., and Apley, D. W., "Singularity Issues in Fixture Fault Diagnosis for Multi-Station Assembly Processes," ASME Journal of Manufacturing Science and Engineering, 126(1), pp. 200-210, 2004.

Apley, D. W., "A Cautious Minimum Variance Controller with ARIMA Disturbances," IIE Transactions, 36(5), pp. 417-432, 2004.

Shiu, B. W., Apley, D. W., Ceglarek, D., and Shi, J., "Tolerance Allocation for Compliant Beam Structure Assemblies," IIE Transactions, 35(4), pp. 329-342, 2003.

Apley, D. W. and Lee, H. Y., "Identifying Spatial Variation Patterns in Multivariate Manufacturing Processes:  A Blind Separation Approach," Technometrics, 45(3), pp. 220-234, 2003.

Apley, D. W. and Lee, H. C., "Design of Exponentially Weighted Moving Average Control Charts for Autocorrelated Processes with Model Uncertainty," Technometrics, 45(3), pp. 187-198, 2003.

Tsung, F. and Apley, D. W., "The Dynamic T2 Chart for Monitoring Feedback-Controlled Processes," IIE Transactions, 34(12), pp. 1043-1053, 2002.  Received the 2002-2003 IIE Transactions Best Paper Award for Quality and Reliability.

Apley, D. W., "Time Series Control Charts in the Presence of Model Uncertainty," ASME Journal of Manufacturing Science and Engineering, 124(4), pp. 891-898, 2002.

Shu, L., Apley, D.W., and Tsung, F. "Autocorrelated Process Monitoring Using Triggered Cuscore Charts," Quality and Reliability Engineering International, 18(5), pp. 411-421, 2002.

Apley, D. W. and Tsung, F., "The Autoregressive T2 Chart for Monitoring Univariate Autocorrelated Processes," Journal of Quality Technology, 34(1), pp. 80-96, 2002.

Apley, D. W. and Shi, J., "A Factor Analysis Method for Diagnosing Variability in Multivariate Manufacturing Processes," Technometrics, 43(1), pp. 84-95, 2001.

Apley, D. W. and Shi, J., "The GLRT for Statistical Process Control of Autocorrelated Processes," IIE Transactions, 31(12), pp. 1123-1134, 1999.

Apley, D. W. and Shi, J., "An Order Downdating Algorithm for Tracking System Order and Parameters in Recursive Least Squares Identification," IEEE Transactions on Signal Processing, 47(11), pp. 3134-3137, 1999.

Apley, D. W. and Shi, J., "Diagnosis of Multiple Fixture Faults in Panel Assembly," ASME Journal of Manufacturing Science and Engineering, 120(4), pp. 793-801, 1998.

Shi, J. and Apley, D. W., "A Suboptimal N-step-ahead Cautious Controller for Adaptive Control Applications," ASME Journal of Dynamic Systems, Measurement, and Control, 120(3), pp. 419-423, 1998.

Apley, D. W., Seliger, G., Voit, L., and Shi, J., "Diagnostics in Disassembly Unscrewing Operations," International Journal of Flexible Manufacturing Systems, 10(2), pp. 111-128, 1998.