Now showing items 1-20 of 39

    • A Model to Predict the Impact of Specification Changes on Chloride-Induced Corrosion Service Life of Virginia Bridge Decks 

      Trevor J. Kirkpatrick; Richard E. Weyers; Anderson-Cook, Christine M.; Michael M. Sprinkel; Michael C. Brown (Virginia Center for Transportation Innovation and Research, 2002-10)
      A model to determine the time to first repair and subsequent rehabilitation of concrete bridge decks exposed to chloride deicer salts that recognizes and incorporates the statistical nature of factors affecting the corrosion ...
    • Construction Concepts for Continuum Regression 

      Spitzner, Dan J. (Virginia Tech, 2004-08-28)
      Approaches for meaningful regressor construction in the linear prediction problem are investigated in a framework similar to partial least squares and continuum regression, but weighted to allow for intelligent specification ...
    • On the Distribution of Hotelling's T² Statistic Based on the Successive Differences Covariance Matrix Estimator 

      Williams, James D.; Woodall, William H.; Birch, Jeffrey B.; Sullivan, Joe H. (Virginia Tech, 2004-09-30)
      In the historical (or retrospective or Phase I) multivariate data analysis, the choice of the estimator for the variance-covariance matrix is crucial to successfully detecting the presence of special causes of variation. ...
    • Evaluating And Interpreting Interactions 

      Hinkelmann, Klaus (Virginia Tech, 2004-12-13)
      The notion of interaction plays an important − and sometimes frightening − role in the analysis and interpretation of results from observational and experimental studies. In general, results are much easier to explain and ...
    • Robust Parameter Design: A Semi-Parametric Approach 

      Pickle, Stephanie M.; Robinson, Timothy J.; Birch, Jeffrey B.; Anderson-Cook, Christine M. (Virginia Tech, 2005)
      Parameter design or robust parameter design (RPD) is an engineering methodology intended as a cost-effective approach for improving the quality of products and processes. The goal of parameter design is to choose the levels ...
    • High Breakdown Estimation Methods for Phase I Multivariate Control Charts 

      Jensen, Willis A.; Birch, Jeffrey B.; Woodall, William H. (Virginia Tech, 2005)
      The goal of Phase I monitoring of multivariate data is to identify multivariate outliers and step changes so that the estimated control limits are sufficiently accurate for Phase II monitoring. High breakdown estimation ...
    • A Bayesian Hierarchical Approach to Dual Response Surface Modeling 

      Chen, Younan; Ye, Keying (Virginia Tech, 2005)
      In modern quality engineering, dual response surface methodology is a powerful tool to monitor an industrial process by using both the mean and the standard deviation of the measurements as the responses. The least squares ...
    • Cost Penalized Estimation and Prediction Evaluation for Split-Plot Designs 

      Liang, Li; Anderson-Cook, Christine M.; Robinson, Timothy J. (Virginia Tech, 2005-02-02)
      The use of response surface methods generally begins with a process or system involving a response y that depends on a set of k controllable input variables (factors) x₁, x₂,…,xk. To assess the effects of these factors on ...
    • Speculations Concerning the First Ultraintelligent Machine 

      Good, Irving John (Virginia Tech, 2005-03-05)
      The survival of man depends on the early construction of an ultraintelligent machine. In order to design an ultraintelligent machine we need to understand more about the human brain or human thought or both. In the following ...
    • Statistical Monitoring of Heteroscedastic Dose-Response Profiles from High-throughput Screening 

      Williams, J.D.; Birch, Jeffrey B.; Woodall, William H.; Ferry, N.M. (Virginia Tech, 2006)
      In pharmaceutical drug discovery and agricultural crop product discovery, in vivo bioassay experiments are used to identify promising compounds for further research. The reproducibility and accuracy of the bioassay is ...
    • A Semiparametric Approach to Dual Modeling 

      Robinson, Timothy J.; Birch, Jeffrey B.; Starnes, B. Alden (Virginia Tech, 2006)
      In typical normal theory regression, the assumption of homogeneity of variances is often not appropriate. When heteroscedasticity exists, instead of treating the variances as a nuisance and transforming away the heterogeneity, ...
    • A Finite Mixture Approach for Identification of Geographic Regions with Distinctive Ecological Stressor-Response Relationships 

      Farrar, David; Prins, Samantha C. Bates; Smith, Eric P. (Virginia Tech, 2006)
      We study a model-based clustering procedure that aims to identify geographic regions with distinctive relationships among ecological and environmental variables. We use a finite mixture model with a distinct linear regression ...
    • Profile Monitoring via Linear Mixed Models 

      Jensen, Willis A.; Birch, Jeffrey B.; Woodall, William H. (Virginia Tech, 2006)
      Profile monitoring is a relatively new technique in quality control used when the product or process quality is best represented by a profile (or a curve) at each time period. The essential idea is often to model the profile ...
    • Profile Monitoring via Nonlinear Mixed Models 

      Jensen, Willis A.; Birch, Jeffrey B. (Virginia Tech, 2006)
      Profile monitoring is a relatively new technique in quality control best used where the process data follows a profile (or curve) at each time period. Little work has been done on the monitoring on nonlinear profiles. ...
    • Approaches to the Label-Switching Problem of Classification, Based on Partition-Space Relabeling and Label-Invariant Visualization 

      Farrar, David (Virginia Tech, 2006-07-15)
      In the context of interest, a method of cluster analysis is used to classify a set of units into a fixed number of classes. Simulation procedures with various conceptual foundations may be used to evaluate uncertainty, ...
    • Clustering Monitoring Stations Based on Two Rank-Based Criteria of Similarity of Temporal Profiles 

      Farrar, David; Smith, Eric (Virginia Tech, 2006-09)
      To support evaluation of water quality trends, a water quality variable may be measured at a series of points in time, at multiple stations. Summarization of such data and detection of spatiotemporal patterns may benefit ...
    • Linear Mixed Model Robust Regression 

      Waterman, Megan J.; Birch, Jeffrey B.; Schabenberger, Oliver (Virginia Tech, 2006-11-05)
      Mixed models are powerful tools for the analysis of clustered data and many extensions of the classical linear mixed model with normally distributed response have been established. As with all parametric models, correctness ...
    • Statistical Monitoring of Nonlinear Product and Process Quality Profiles 

      Williams, James D.; Woodall, William H.; Birch, Jeffrey B. (Virginia Tech, 2007)
      In many quality control applications, use of a single (or several distinct) quality characteristic(s) is insufficient to characterize the quality of a produced item. In an increasing number of cases, a response curve ...
    • Error Models in Geographic Information Systems Vector Data Using Bayesian Methods 

      Love, Kimberly R.; Ye, Keying; Smith, Eric P.; Prisley, Stephen P. (Virginia Tech, 2007)
      Geographic Information Systems, or GIS, has been an evolving science since its introduction. Recently, many users have become concerned with the incorporation of error analysis into GIS map products. In particular, there ...
    • Monitoring Markov Dependent Observations with a Log-Likelihood Based CUSUM 

      Mousavi, Shabnam; Reynolds, Marion R. Jr. (Virginia Tech, 2008)
      When control charts are used to monitor a proportion p it is traditionally assumed that the binary observations are independent. The work that has been done on monitoring autocorrelated binary observations has assumed a ...