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side the empirical MI, denoted by ˆI(Xf , Y )8, under some problem settings can offer
algorithmic solutions for the resulting complexity regularized problem. One example
of this is presented in following sections and another was recently shown in [64] for
addressing the MPE filter bank decomposition using Wavelet Packets (WPs).
Returning to the problem generally denoting by ˆI(f ) and R(f ) the approximated
fidelity and cost terms for f 2 D, respectively, (2.11) can be approximated by,
f ( ) = arg min
f2D
(ˆI(f )) + · (R(f )), (2.12)
where considering the tendency of the new fidelity-cost indicators, (·) should be a
strictly decreasing real function and (·), a strictly increasing function from N to R.
Noting that the real dependency between Bayes and estimation errors in terms of our
new fidelity complexity values, ˆI(f ) and R(f ), is hidden and, furthermore, problem
dependent, then , and provide degrees of freedom for approximating the oracle
MPE-SR in (2.11). It is interesting to note that independent of those degrees of freedom,
under the proposed approximation the optimal solution f ( ) can be expressed by
f ( ) = arg min
f2{f
k :k2K(D)}
(ˆI(f )) + · (R(f )), (2.13)
with {f
k : k 2 K(D)} D the solutions of the following cost-fidelity problem,
f
k = arg max
f2D
R(f ) k
ˆI (f ) , (2.14)
8k 2 K(D), where K(D) {R(f ) : f 2 D} N. Then, the approximated MPE-SR
solution in (2.12) can be restricted, without any loss, to what we call the optimal
achievable cost-fidelity family {f
k : k 2 K(D)}. Note that the cardinality ofK(D) could
88f 2 D the empirical MI ˆI(Xf , Y ) can be obtained from the available empirical distribution ˆ PXf ,Y .
20
Object Description
| Title | On optimal signal representation for statistical learning and pattern recognition |
| Author | Silva, Jorge |
| Author email | jorgesil@usc.edu; josilva@ing.uchile.cl |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Electrical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2008-06-23 |
| Date submitted | 2008 |
| Restricted until | Unrestricted |
| Date published | 2008-10-21 |
| Advisor (committee chair) | Narayanan, Shrikanth S. |
| Advisor (committee member) |
Kuo, C.-C. Jay Ordóñez, Fernando I. |
| Abstract | This work presents contributions on two important aspects of the role of signal representation in statistical learning problems, in the context of deriving new methodologies and representations for speech recognition and the estimation of information theoretic quantities.; The first topic focuses on the problem of optimal filter bank selection using Wavelet Packets (WPs) for speech recognition applications. We propose new results to show an estimation-approximation error tradeoff across sequence of embedded representations. These results were used to formulate the minimum probability of error signal representation (MPE-SR) problem as a complexity regularization criterion. Restricting this criterion to the filter bank selection, algorithmic solutions are provided by exploring the dyadic tree-structure of WPs. These solutions are stipulated in terms of a set of conditional independent assumptions for the acoustic observation process, in particular, a Markov tree property across the indexed structure of WPs. In the technical side, this work presents contributions on the extension of minimum cost tree pruning algorithms and their properties to affine tree functionals. For the experimental validation, a phone classification task ratifies the goodness of Wavelet Packets as an analysis scheme for non-stationary time-series processes, and the effectiveness of the MPE-SR to provide cost effective discriminative filter bank solution for pattern recognition.; The second topic addresses the problem of data-dependent partitions for the estimation of mutual information and Kullback-Leibler divergence (KLD). This work proposes general histogram-based estimates considering non-product data-driven partition schemes. The main contribution is the stipulation of sufficient conditions to make these histogram-based constructions strongly consistent for both problems. The sufficient conditions consider combinatorial complexity indicator for partition families and the use of large deviation type of inequalities (Vapnik-Chervonenkis inequalities). On the application side, two emblematic data-dependent constructions are derived from this result, one based on statistically equivalent blocks and the other, on a tree-structured vector quantization scheme. A range of design values was stipulated to guarantee strongly consistency estimates for both framework. Furthermore, experimental results under controlled settings demonstrate the superiority of these data-driven techniques in terms of a bias-variance analysis when compared to conventional product histogram-based and kernel plug-in estimates. |
| Keyword | signal representation in statistical learning; Bayes decision theory; basis selection; tree-structured bases and Wavelet packet (WP); complexity regularization; minimum cost tree pruning; family pruning problem; mutual information estimation; divergence estimation; data-dependent partitions; statistical learning theory; concentration inequalities; tree-structured vector quantization. |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m1684 |
| Contributing entity | University of Southern California |
| Rights | Silva, Jorge |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@lib.usc.edu |
| Filename | etd-Silva-2450 |
| Archival file | uscthesesreloadpub_Volume32/etd-Silva-2450.pdf |
Description
| Title | Page 33 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | side the empirical MI, denoted by ˆI(Xf , Y )8, under some problem settings can offer algorithmic solutions for the resulting complexity regularized problem. One example of this is presented in following sections and another was recently shown in [64] for addressing the MPE filter bank decomposition using Wavelet Packets (WPs). Returning to the problem generally denoting by ˆI(f ) and R(f ) the approximated fidelity and cost terms for f 2 D, respectively, (2.11) can be approximated by, f ( ) = arg min f2D (ˆI(f )) + · (R(f )), (2.12) where considering the tendency of the new fidelity-cost indicators, (·) should be a strictly decreasing real function and (·), a strictly increasing function from N to R. Noting that the real dependency between Bayes and estimation errors in terms of our new fidelity complexity values, ˆI(f ) and R(f ), is hidden and, furthermore, problem dependent, then , and provide degrees of freedom for approximating the oracle MPE-SR in (2.11). It is interesting to note that independent of those degrees of freedom, under the proposed approximation the optimal solution f ( ) can be expressed by f ( ) = arg min f2{f k :k2K(D)} (ˆI(f )) + · (R(f )), (2.13) with {f k : k 2 K(D)} D the solutions of the following cost-fidelity problem, f k = arg max f2D R(f ) k ˆI (f ) , (2.14) 8k 2 K(D), where K(D) {R(f ) : f 2 D} N. Then, the approximated MPE-SR solution in (2.12) can be restricted, without any loss, to what we call the optimal achievable cost-fidelity family {f k : k 2 K(D)}. Note that the cardinality ofK(D) could 88f 2 D the empirical MI ˆI(Xf , Y ) can be obtained from the available empirical distribution ˆ PXf ,Y . 20 |
