摘要(英) |
A mixture experiment is an experiment in which the k ingredients are nonnegative and subject to the simplex restriction Σx_i=1 on the (k-1)-dimensional probability simplex S^{k-1}. This dissertation discusses optimal designs for linear and quadratic log contrast models for experiments with mixtures suggested by Aitchison and Bacon-Shone (1984), where the experimental domain is restricted further as in Chan (1992). In this study, firstly, an essentially complete class of designs under the Kiefer ordering for linear log contrast models with mixture experiments is presented. Based on the completeness result, Φ_p-optimal designs for all p, -∞<p≤1 including D- and A-optimal are obtained, where the eigenvalues of the design moment matrix are used. By using the approach presented here, we gain insight on how these Φ_p-optimal designs behave. Following that, the exact N-point D-optimal designs for linear log contrast models with three and four ingredients are further investigated. The results show that for k=3 and N=3p+q ,1 ≤q≤2, there is an exact N-point D-optimal design supported at the points of S_1 (S_2) with equal weight n/N, 0≤n≤p , and puts the remaining weight (N-3n)/N uniformly on the points of S_2 (S_1) as evenly as possible, where S_1 and S_2 are sets of the supports of the approximate D-optimal designs. When k=4 and N=6p+q , 1 ≤q≤5, an exact N-point design which distributes the weights as evenly as possible among the supports of the approximate D-optimal design is proved to be exact D-optimal. Thirdly, the approximate D_s-optimal designs for discriminating between linear and quadratic log contrast models for experiments with mixtures are derived. It is shown that for a symmetric subspace of the finite dimensional simplex, there is a D_s-optimal design with the nice structure that puts a weight 1/(2^{k-1}) on the centroid of this subspace and the remaining weight is uniformly distributed on the vertices of the experimental domain. Moreover, the D_s-efficiency of the D-optimal design for quadratic model and the design given by Aitchison and Bacon-Shone (1984) are also discussed Finally, we show that an essentially complete class of designs under the Kiefer ordering for the quadratic log contrast model is the set of all designs in the boundary of T or origin of T . Based on the completeness result, numerical Φ_p -optimal designs for some p, -∞<p≤1 are obtained. |
參考文獻 |
[1] Aitchison, J. and Bacon-Shone, J. (1984). Log contrast models for experiments with mixtures. Biometrika, 71, 323-330. [2] Atwood, C. L. (1969). Optimal and efficient designs of experiments. The Annals of Mathematical Statistics, 40, 1570-1602. [3] Chan, L. Y. (1988). Optimal design for a linear log contrast model for experiments with mixtures. Journal of Statistical Planning and Inference, 20, 105-113. [4] Chan, L. Y. (1992). D-Optimal design for a quadratic log contrast model for experiments with mixtures. Communications in Statistics-Theory and Methods, 21(10), 2909-2930. [5] Chan, L. Y. and Guan, Y. N. (2001). A- and D-optimal designs for a log contrast model for experiments with mixtures. Journal of Applied Statistics, 28, 537-546. [6] Chang, F. C. and Chen, Y. H. (2004). D-optimal designs for multivariate linear and quadratic polynomial regression. Journal of the Chinese Statistical Association, 40, 383-402. [7] Cheng, C. S. (1987). An application of the Kiefer-Wolfowitz equivalence theorem to a problem in Hadamard transform optics. Annals of Statistics, 15, 1593-1603. [8] Cheng, C. S. (1995). Complete class results for the moment matrices of designs over permutation-invariant sets. Annals of Statistics, 23, 41-54. [9] Cornell, J. A. (2002). Experiments with Mixtures. Design, Models and Analysis of Mixture Data. 3nd ed. Wiley, New York. [10] Draper, N. R. Gaffke, N. and Pukelsheim, F. (1991). First and second order rotatability of experimental designs, moment matrices, and information surfaces. Metrika, 38, 129-161. [11] Draper, N. R. and Pukelsheim, F. (1999). Kiefer ordering of simplex designs for first- and second-degree mixture models. Journal of Statistical Planning and Inference, 79, 325-348. [12] Draper, N. R., Heiligers, B. and Pukelsheim, F. (2000). Kiefer ordering of simplex designs for second-degree mixture models with four or more ingredients. Annals of Statistics, 28(2), 578-590. [13] Fedorov, V. V. (1972). Theory of Optimal Experiments. Translated and Edited by W. J. Studden and E. M. Klimko. Academic Press, New York. [14] Gaffke, N. and Krafft O. (1982). Exact D-optimum designs for quadratic regression. Journal of the Royal Statistical Society. Series B, 40, 394-397. [15] Gaffke, N. (1987). On D-optimality of exact linear regression designs with minimum support. Journal of Statistical Planning and Inference, 15, 189-204. [16] Giovagnoli, A., Pukelsheim, F. and Wynn, H. (1987). Group invariant orderings and experimental designs. Journal of Statistical Planning and Inference, 17, 159-171. [17] Heiligers, B. and Hilgers, R. D. (2003). A note on optimal mixture and mixture amount designs. Statistica Sinica, 13, 709-725. [18] Huang, M.-N. L. (1987). Exact D-optimal designs for polynomial regression. Bulletin of the Institute of Mathematics, Academia Sinica, 15, 59-71. [19] Huang, M.-N. L. and Wu, S. C. (2005). Exact D-optimal designs for mixture experiments in Scheffe's quadratic models. Unpublished, Master's thesis, National Sun Yat-sen University, Kaohsiung, Taiwan, Republic of China. [20] Karlin, S. and Studden, W. J. (1966). Optimal experimental designs. The Annals of Mathematical Statistics, 37, 783-815. [21] Kiefer, J. (1959). Optimum experimental designs (with discussion). Journal of the Royal Statistical Society, Series B, 21, 272-319. [22] Kiefer, J. (1961). Optimal designs in regression problems, II. The Annals of Mathematical Statistics, 32, 298-325. [23] Klein, T. (2004a). Optimal designs for second-degree Kronecker model mixture experiments. Journal of Statistical Planning and Inference, 123, 117-131. [24] Klein, T. (2004b). Invariant symmetric block matrices for the design of mixture experiments. Linear Algebra and its Applications, 388, 261-278. [25] Lim, Y. B. and Studden, W. J. (1988). Efficient D_s-optimal designs for multivariate polynomial regression on the q-cube. The Annals of Statistics, 16(3), 1225-1240. [26] Pukelsheim, F. (1987). Information Invreasing Orderings in Experimental Design Theory. International Statistical Review, 55(2), 203-219. [27] Pukelsheim, F. (1989). Complete class results for linear regression designs over the multi-dimensional cube. In Contributions to Probability and Statistics. Essays in Honor of Ingram Olkin (L. J. Gleser, M. D. Perlman, S. J. Press and A. R. Sampson, eds.) 349-356. Springer, New York. [28] Pukelsheim, F. (1993). Optimal Design of Experiments. Wiley, New York. [29] Salaevskii O. V. (1966). The problem of the distribution of observations in polynomial regression. Proceedings of the Steklov Institute of Mathematics, 79, 146-166. |