wavelets 94
[0805.1404] Adaptive estimation of a distribution function and its density in sup-norm loss by wavelet and spline projections
18 days ago by cshalizi
"Given an i.i.d. sample from a distribution $F$ on $mathbb{R}$ with uniformly continuous density $p_0$, purely data-driven estimators are constructed that efficiently estimate $F$ in sup-norm loss and simultaneously estimate $p_0$ at the best possible rate of convergence over H"older balls, also in sup-norm loss. The estimators are obtained by applying a model selection procedure close to Lepski's method with random thresholds to projections of the empirical measure onto spaces spanned by wavelets or $B$-splines. The random thresholds are based on suprema of Rademacher processes indexed by wavelet or spline projection kernels. This requires Bernstein-type analogs of the inequalities in Koltchinskii [Ann. Statist. 34 (2006) 2593-2656] for the deviation of suprema of empirical processes from their Rademacher symmetrizations."
to:NB
density_estimation
wavelets
splines
statistics
empirical_processes
18 days ago by cshalizi
[math/0510311] Adaptive density estimation under dependence
12 weeks ago by cshalizi
"Assume that $(X_t)_{tinZ}$ is a real valued time series admitting a common marginal density $f$ with respect to Lebesgue's measure. Donoho {it et al.} (1996) propose a near-minimax method based on thresholding wavelets to estimate $f$ on a compact set in an independent and identically distributed setting. The aim of the present work is to extend these results to general weak dependent contexts. Weak dependence assumptions are expressed as decreasing bounds of covariance terms and are detailed for different examples. The threshold levels in estimators $widehat f_n$ depend on weak dependence properties of the sequence $(X_t)_{tinZ}$ through the constant. If these properties are unknown, we propose cross-validation procedures to get new estimators. These procedures are illustrated via simulations of dynamical systems and non causal infinite moving averages. We also discuss the efficiency of our estimators with respect to the decrease of covariances bounds."
to:NB
statistics
density_estimation
wavelets
time_series
statistical_inference_for_stochastic_processes
12 weeks ago by cshalizi
[1111.3994] Adaptive estimation of an additive regression function from weakly dependent data
november 2011 by cshalizi
"A $d$-dimensional nonparametric additive regression model with dependent observations is considered. Using the marginal integration and the methods of wavelets, we develop a new adaptive estimator for a component of the additive regression function. Its asymptotic properties are investigated via the minimax approach under the $mathbb{L}_2$ risk over Besov balls. We prove that it attains a sharp rate of convergence, close to the one obtained in the one-dimensional case. In particular, it is both independent of $d$ and slightly deteriorated by the dependence of the observations."
to:NB
statistics
wavelets
regression
statistical_inference_for_stochastic_processes
november 2011 by cshalizi
in-cites - An Essay by Dr. David Donoho
november 2011 by cshalizi
Donoho on how to get highly cited. I suspect some of it is not entirely serious, but it's a bit hard to tell.
statistics
academia
bibliometry
wavelets
donoho.david
via:stodden
to_teach
to:blog
november 2011 by cshalizi
[1110.1485] A Face Recognition Scheme using Wavelet Based Dominant Features
october 2011 by Vaguery
"In this paper, a multi-resolution feature extraction algorithm for face recognition is proposed based on two-dimensional discrete wavelet transform (2D-DWT), which efficiently exploits the local spatial variations in a face image. For the purpose of feature extraction, instead of considering the entire face image, an entropy-based local band selection criterion is developed, which selects high-informative horizontal segments from the face image. In order to capture the local spatial variations within these highinformative horizontal bands precisely, the horizontal band is segmented into several small spatial modules. Dominant wavelet coefficients corresponding to each local region residing inside those horizontal bands are selected as features. In the selection of the dominant coefficients, a threshold criterion is proposed, which not only drastically reduces the feature dimension but also provides high within-class compactness and high between-class separability. A principal component analysis is performed to further reduce the dimensionality of the feature space. Extensive experimentation is carried out upon standard face databases and a very high degree of recognition accuracy is achieved by the proposed method in comparison to those obtained by some of the existing methods."
face-recognition
algorithms
image-processing
wavelets
nudge-targets
october 2011 by Vaguery
[1101.4744] Clustering functional data using wavelets
october 2011 by Vaguery
"We present two methods for detecting patterns and clusters in high dimensional time-dependent functional data. Our methods are based on wavelet-based similarity measures, since wavelets are well suited for identifying highly discriminant local time and scale features. The multiresolution aspect of the wavelet transform provides a time-scale decomposition of the signals allowing to visualize and to cluster the functional data into homogeneous groups. For each input function, through its empirical orthogonal wavelet transform the first method uses the distribution of energy across scales generate a handy number of features that can be sufficient to still make the signals well distinguishable. Our new similarity measure combined with an efficient feature selection technique in the wavelet domain is then used within more or less classical clustering algorithms to effectively differentiate among high dimensional populations. The second method uses dissimilarity measures between the whole time-scale representations and are based on wavelet-coherence tools. The clustering is then performed using a k-centroid algorithm starting from these dissimilarities. Practical performance of these methods that jointly designs both the feature selection in the wavelet domain and the classification distance is demonstrated through simulations as well as daily profiles of the French electricity power demand."
classification
time-series
feature-extraction
machine-learning
multiobjective-optimization
ontology-discovery
wavelets
nudge-targets
october 2011 by Vaguery
Nonlinear Black-Box Modeling in System Identification: a Unified Overview
july 2011 by matsk
Jonas Sjöberg et. al.
1995-06-21
math
neural-networks
nonlinear
modeling
wavelets
fuzzy
1995-06-21
july 2011 by matsk
Bear Products International Home Page
december 2010 by arsyed
"This is the Internet domain of Ian Kaplan and Bear Products International ... we specialize in well engineered and extensively documented large scale software projects. These include:
Financial trading and modeling software
Compilers and language processors
Digital Signal Processing Software"
people
wavelets
programming
finance
dsp
Financial trading and modeling software
Compilers and language processors
Digital Signal Processing Software"
december 2010 by arsyed
[1007.5413] Optimization of Financial Instrument Parcels in Stochastic Wavelet Model
august 2010 by Vaguery
"To define oscillatory movements of securities market, we put in the non-local extension of Ito- equation for wavelet-images of random processes. It is proposed an algorithm of creation of evolutionary equation and a model of prediction of the most probable price movement path. It is carried out experimental validation of findings."
wavelets
financial-engineering
nudge-targets
algorithms
evolutionary-algorithms
heuristics
prediction
august 2010 by Vaguery
[1007.0626] Fusion of Wavelet Coefficients from Visual and Thermal Face Images for Human Face Recognition - A Comparative Study
august 2010 by Vaguery
"In this paper we present a comparative study on fusion of visual and thermal images using different wavelet transformations. Here, coefficients of discrete wavelet transforms from both visual and thermal images are computed separately and combined. Next, inverse discrete wavelet transformation is taken in order to obtain fused face image. Both Haar and Daubechies (db2) wavelet transforms have been used to compare recognition results. For experiments IRIS Thermal/Visual Face Database was used. Experimental results using Haar and Daubechies wavelets show that the performance of the approach presented here achieves maximum success rate of 100% in many cases."
image-analysis
wavelets
machine-learning
algorithms
nudge-targets
august 2010 by Vaguery
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