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23,002
Development of ICA and IVA Algorithms with Application to Medical Image Analysis
stat.ML
Independent component analysis (ICA) is a widely used BSS method that can uniquely achieve source recovery, subject to only scaling and permutation ambiguities, through the assumption of statistical independence on the part of the latent sources. Independent vector analysis (IVA) extends the applicability of ICA by joi...
computer science
23,003
Covariance-based Dissimilarity Measures Applied to Clustering Wide-sense Stationary Ergodic Processes
stat.ML
We introduce a new unsupervised learning problem: clustering wide-sense stationary ergodic stochastic processes. A covariance-based dissimilarity measure and consistent algorithms are designed for clustering offline and online data settings, respectively. We also suggest a formal criterion on the efficiency of dissimil...
computer science
23,004
Solving for multi-class using orthogonal coding matrices
stat.ML
Probability estimates are desirable in statistical classification both for gauging the accuracy of a classification result and for calibration. Here we describe a method of solving for the conditional probabilities in multi-class classification using orthogonal error correcting codes. The method is tested on six differ...
computer science
23,005
Gradient descent revisited via an adaptive online learning rate
stat.ML
Any gradient descent optimization requires to choose a learning rate. With deeper and deeper models, tuning that learning rate can easily become tedious and does not necessarily lead to an ideal convergence. We propose a variation of the gradient descent algorithm in the which the learning rate is not fixed. Instead, w...
computer science
23,006
Adaptive Scan Gibbs Sampler for Large Scale Inference Problems
stat.ML
For large scale on-line inference problems the update strategy is critical for performance. We derive an adaptive scan Gibbs sampler that optimizes the update frequency by selecting an optimum mini-batch size. We demonstrate performance of our adaptive batch-size Gibbs sampler by comparing it against the collapsed Gibb...
computer science
23,007
Bayesian Nonparametric Modeling of Driver Behavior using HDP Split-Merge Sampling Algorithm
stat.ML
Modern vehicles are equipped with increasingly complex sensors. These sensors generate large volumes of data that provide opportunities for modeling and analysis. Here, we are interested in exploiting this data to learn aspects of behaviors and the road network associated with individual drivers. Our dataset is collect...
computer science
23,008
Marketing Analytics: Methods, Practice, Implementation, and Links to Other Fields
stat.ML
Marketing analytics is a diverse field, with both academic researchers and practitioners coming from a range of backgrounds including marketing, operations research, statistics, and computer science. This paper provides an integrative review at the boundary of these three areas. The topics of visualization, segmentatio...
computer science
23,009
Approximate Vanishing Ideal via Data Knotting
stat.ML
The vanishing ideal is a set of polynomials that takes zero value on the given data points. Originally proposed in computer algebra, the vanishing ideal has been recently exploited for extracting the nonlinear structures of data in many applications. To avoid overfitting to noisy data, the polynomials are often designe...
computer science
23,010
Tournament Leave-pair-out Cross-validation for Receiver Operating Characteristic (ROC) Analysis
stat.ML
Receiver operating characteristic (ROC) analysis is widely used for evaluating diagnostic systems. Recent studies have shown that estimating an area under ROC curve (AUC) with standard cross-validation methods suffers from a large bias. The leave-pair-out (LPO) cross-validation has been shown to correct this bias. Howe...
computer science
23,011
Information Directed Sampling and Bandits with Heteroscedastic Noise
stat.ML
In the stochastic bandit problem, the goal is to maximize an unknown function via a sequence of noisy function evaluations. Typically, the observation noise is assumed to be independent of the evaluation point and satisfies a tail bound taken uniformly on the domain. In this work, we consider the setting of heterosceda...
computer science
23,012
Transformation Autoregressive Networks
stat.ML
The fundamental task of general density estimation $p(x)$ has been of keen interest to machine learning. In this work, we attempt to systematically characterize methods for density estimation. Broadly speaking, most of the existing methods can be categorized into either using: \textit{a}) autoregressive models to estim...
computer science
23,013
Probabilistic Recurrent State-Space Models
stat.ML
State-space models (SSMs) are a highly expressive model class for learning patterns in time series data and for system identification. Deterministic versions of SSMs (e.g. LSTMs) proved extremely successful in modeling complex time series data. Fully probabilistic SSMs, however, are often found hard to train, even for ...
computer science
23,014
Nonparametric Quantile-Based Causal Discovery
stat.ML
Telling cause from effect using observational data is a challenging problem, especially in the bivariate case. Contemporary methods often assume an independence between the cause and the generating mechanism of the effect given the cause. From this postulate, they derive asymmetries to uncover causal relationships. In ...
computer science
23,015
Composite Gaussian Processes: Scalable Computation and Performance Analysis
stat.ML
Gaussian process (GP) models provide a powerful tool for prediction but are computationally prohibitive using large data sets. In such scenarios, one has to resort to approximate methods. We derive an approximation based on a composite likelihood approach using a general belief updating framework, which leads to a recu...
computer science
23,016
Greedy Active Learning Algorithm for Logistic Regression Models
stat.ML
We study a logistic model-based active learning procedure for binary classification problems, in which we adopt a batch subject selection strategy with a modified sequential experimental design method. Moreover, accompanying the proposed subject selection scheme, we simultaneously conduct a greedy variable selection pr...
computer science
23,017
An Instability in Variational Inference for Topic Models
stat.ML
Topic models are Bayesian models that are frequently used to capture the latent structure of certain corpora of documents or images. Each data element in such a corpus (for instance each item in a collection of scientific articles) is regarded as a convex combination of a small number of vectors corresponding to `topic...
computer science
23,018
Comparison of computer systems and ranking criteria for automatic melanoma detection in dermoscopic images
stat.ML
Melanoma is the deadliest form of skin cancer. Computer systems can assist in melanoma detection, but are not widespread in clinical practice. In 2016, an open challenge in classification of dermoscopic images of skin lesions was announced. A training set of 900 images with corresponding class labels and semi-automatic...
computer science
23,019
Information Assisted Dictionary Learning for fMRI data analysis
stat.ML
Extracting information from functional magnetic resonance images (fMRI) has been a major area of research for many years, but is still demanding more accurate techniques. Nowadays, we have a plenty of available information about the brain-behavior that can be used to develop more precise methods. Thus, this paper prese...
computer science
23,020
Multi-View Bayesian Correlated Component Analysis
stat.ML
Correlated component analysis as proposed by Dmochowski et al. (2012) is a tool for investigating brain process similarity in the responses to multiple views of a given stimulus. Correlated components are identified under the assumption that the involved spatial networks are identical. Here we propose a hierarchical pr...
computer science
23,021
Multi-set Canonical Correlation Analysis simply explained
stat.ML
There are a multitude of methods to perform multi-set correlated component analysis (MCCA), including some that require iterative solutions. The methods differ on the criterion they optimize and the constraints placed on the solutions. This note focuses perhaps on the simplest version, which can be solved in a single s...
computer science
23,022
Region Detection in Markov Random Fields: Gaussian Case
stat.ML
In this work we consider the problem of model selection in Gaussian Markov fields in the sample deficient scenario. The benchmark information-theoretic results in the case of d-regular graphs require the number of samples to be at least proportional to the logarithm of the number of vertices to allow consistent graph r...
computer science
23,023
Gaussian Process Classification with Privileged Information by Soft-to-Hard Labeling Transfer
stat.ML
Learning using privileged information is an attractive problem setting that helps many learning scenarios in the real world. A state-of-the-art method of Gaussian process classification (GPC) with privileged information is GPC+, which incorporates privileged information into a noise term of the likelihood. A drawback o...
computer science
23,024
Safe Triplet Screening for Distance Metric Learning
stat.ML
We study safe screening for metric learning. Distance metric learning can optimize a metric over a set of triplets, each one of which is defined by a pair of same class instances and an instance in a different class. However, the number of possible triplets is quite huge even for a small dataset. Our safe triplet scree...
computer science
23,025
Deep Neural Networks Learn Non-Smooth Functions Effectively
stat.ML
We theoretically discuss why deep neural networks (DNNs) performs better than other models in some cases by investigating statistical properties of DNNs for non-smooth functions. While DNNs have empirically shown higher performance than other standard methods, understanding its mechanism is still a challenging problem....
computer science
23,026
A probabilistic framework for multi-view feature learning with many-to-many associations via neural networks
stat.ML
A simple framework Probabilistic Multi-view Graph Embedding (PMvGE) is proposed for multi-view feature learning with many-to-many associations. PMvGE is a probabilistic model for predicting new associations via graph embedding of the nodes of data vectors with links of their associations.Multi-view data vectors with ma...
computer science
23,027
Variable Selection and Task Grouping for Multi-Task Learning
stat.ML
We consider multi-task learning, which simultaneously learns related prediction tasks, to improve generalization performance. We factorize a coefficient matrix as the product of two matrices based on a low-rank assumption. These matrices have sparsities to simultaneously perform variable selection and learn and overlap...
computer science
23,028
Superposition-Assisted Stochastic Optimization for Hawkes Processes
stat.ML
We consider the learning of multi-agent Hawkes processes, a model containing multiple Hawkes processes with shared endogenous impact functions and different exogenous intensities. In the framework of stochastic maximum likelihood estimation, we explore the associated risk bound. Further, we consider the superposition o...
computer science
23,029
State Space Gaussian Processes with Non-Gaussian Likelihood
stat.ML
We provide a comprehensive overview and tooling for GP modeling with non-Gaussian likelihoods using state space methods. The state space formulation allows for solving one-dimensional GP models in $\mathcal{O}(n)$ time and memory complexity. While existing literature has focused on the connection between GP regression ...
computer science
23,030
Conditional Density Estimation with Bayesian Normalising Flows
stat.ML
Modeling complex conditional distributions is critical in a variety of settings. Despite a long tradition of research into conditional density estimation, current methods employ either simple parametric forms or are difficult to learn in practice. This paper employs normalising flows as a flexible likelihood model and ...
computer science
23,031
Vertex nomination: The canonical sampling and the extended spectral nomination schemes
stat.ML
Suppose that one particular block in a stochastic block model is deemed "interesting," but block labels are only observed for a few of the vertices. Utilizing a graph realized from the model, the vertex nomination task is to order the vertices with unobserved block labels into a "nomination list" with the goal of havin...
computer science
23,032
Nonnegative PARAFAC2: a flexible coupling approach
stat.ML
Modeling variability in tensor decomposition methods is one of the challenges of source separation. One possible solution to account for variations from one data set to another, jointly analysed, is to resort to the PARAFAC2 model. However, so far imposing constraints on the mode with variability has not been possible....
computer science
23,033
Covariance Function Pre-Training with m-Kernels for Accelerated Bayesian Optimisation
stat.ML
The paper presents a novel approach to direct covariance function learning for Bayesian optimisation, with particular emphasis on experimental design problems where an existing corpus of condensed knowledge is present. The method presented borrows techniques from reproducing kernel Banach space theory (specifically m-k...
computer science
23,034
High Dimensional Bayesian Optimization Using Dropout
stat.ML
Scaling Bayesian optimization to high dimensions is challenging task as the global optimization of high-dimensional acquisition function can be expensive and often infeasible. Existing methods depend either on limited active variables or the additive form of the objective function. We propose a new method for high-dime...
computer science
23,035
History PCA: A New Algorithm for Streaming PCA
stat.ML
In this paper we propose a new algorithm for streaming principal component analysis. With limited memory, small devices cannot store all the samples in the high-dimensional regime. Streaming principal component analysis aims to find the $k$-dimensional subspace which can explain the most variation of the $d$-dimensiona...
computer science
23,036
ICA based on Split Generalized Gaussian
stat.ML
Independent Component Analysis (ICA) - one of the basic tools in data analysis - aims to find a coordinate system in which the components of the data are independent. Most popular ICA methods use kurtosis as a metric of non-Gaussianity to maximize, such as FastICA and JADE. However, their assumption of fourth-order mom...
computer science
23,037
DeepMatch: Balancing Deep Covariate Representations for Causal Inference Using Adversarial Training
stat.ML
We study optimal covariate balance for causal inferences from observational data when rich covariates and complex relationships necessitate flexible modeling with neural networks. Standard approaches such as propensity weighting and matching/balancing fail in such settings due to miscalibrated propensity nets and inapp...
computer science
23,038
Constraining the Dynamics of Deep Probabilistic Models
stat.ML
We introduce a novel generative formulation of deep probabilistic models implementing "soft" constraints on the dynamics of the functions they can model. In particular we develop a flexible methodological framework where the modeled functions and derivatives of a given order are subject to inequality or equality constr...
computer science
23,039
Neural Granger Causality for Nonlinear Time Series
stat.ML
While most classical approaches to Granger causality detection assume linear dynamics, many interactions in applied domains, like neuroscience and genomics, are inherently nonlinear. In these cases, using linear models may lead to inconsistent estimation of Granger causal interactions. We propose a class of nonlinear m...
computer science
23,040
Post Selection Inference with Incomplete Maximum Mean Discrepancy Estimator
stat.ML
Measuring divergence between two distributions is essential in machine learning and statistics and has various applications including binary classification, change point detection, and two-sample test. Furthermore, in the era of big data, designing divergence measure that is interpretable and can handle high-dimensiona...
computer science
23,041
Out-of-sample extension of graph adjacency spectral embedding
stat.ML
Many popular dimensionality reduction procedures have out-of-sample extensions, which allow a practitioner to apply a learned embedding to observations not seen in the initial training sample. In this work, we consider the problem of obtaining an out-of-sample extension for the adjacency spectral embedding, a procedure...
computer science
23,042
Bayesian Uncertainty Estimation for Batch Normalized Deep Networks
stat.ML
Deep neural networks have led to a series of breakthroughs, dramatically improving the state-of-the-art in many domains. The techniques driving these advances, however, lack a formal method to account for model uncertainty. While the Bayesian approach to learning provides a solid theoretical framework to handle uncerta...
computer science
23,043
Recovery of simultaneous low rank and two-way sparse coefficient matrices, a nonconvex approach
stat.ML
We study the problem of recovery of matrices that are simultaneously low rank and row and/or column sparse. Such matrices appear in recent applications in cognitive neuroscience, imaging, computer vision, macroeconomics, and genetics. We propose a GDT (Gradient Descent with hard Thresholding) algorithm to efficiently r...
computer science
23,044
Structured Uncertainty Prediction Networks
stat.ML
This paper is the first work to propose a network to predict a structured uncertainty distribution for a reconstructed image. Our novel model learns to predict a full Gaussian covariance matrix for each reconstruction, which permits efficient sampling and likelihood evaluation. We demonstrate that our model can accurat...
computer science
23,045
High-Quality Prediction Intervals for Deep Learning: A Distribution-Free, Ensembled Approach
stat.ML
Deep neural networks are a powerful technique for learning complex functions from data. However, their appeal in real-world applications can be hindered by an inability to quantify the uncertainty of predictions. In this paper, the generation of prediction intervals (PI) for quantifying uncertainty in regression tasks ...
computer science
23,046
The Gaussian Process Autoregressive Regression Model (GPAR)
stat.ML
Multi-output regression models must exploit dependencies between outputs to maximise predictive performance. The application of Gaussian processes (GPs) to this setting typically yields models that are computationally demanding and have limited representational power. We present the Gaussian Process Autoregressive Regr...
computer science
23,047
Dual Extrapolation for Faster Lasso Solvers
stat.ML
Convex sparsity-inducing regularizations are ubiquitous in high-dimension machine learning, but their non-differentiability requires the use of iterative solvers. To accelerate such solvers, state-of-the-art approaches consist in reducing the size of the optimization problem at hand. In the context of regression, this ...
computer science
23,048
Subspace-Induced Gaussian Processes
stat.ML
We present a new Gaussian process (GP) regression model where the covariance kernel is indexed or parameterized by a sufficient dimension reduction subspace of a reproducing kernel Hilbert space. The covariance kernel will be low-rank while capturing the statistical dependency of the response to the covariates, this af...
computer science
23,049
A Generative Deep Recurrent Model for Exchangeable Data
stat.ML
We present a novel model architecture which leverages deep learning tools to perform exact Bayesian inference on sets of high dimensional, complex observations. Our model is provably exchangeable, meaning that the joint distribution over observations is invariant under permutation: this property lies at the heart of Ba...
computer science
23,050
Path-Specific Counterfactual Fairness
stat.ML
We consider the problem of learning fair decision systems in complex scenarios in which a sensitive attribute might affect the decision along both fair and unfair pathways. We introduce a causal approach to disregard effects along unfair pathways that simplifies and generalizes previous literature. Our method corrects ...
computer science
23,051
An Analysis of Categorical Distributional Reinforcement Learning
stat.ML
Distributional approaches to value-based reinforcement learning model the entire distribution of returns, rather than just their expected values, and have recently been shown to yield state-of-the-art empirical performance. This was demonstrated by the recently proposed C51 algorithm, based on categorical distributiona...
computer science
23,052
Learning Causally-Generated Stationary Time Series
stat.ML
We present the Causal Gaussian Process Convolution Model (CGPCM), a doubly nonparametric model for causal, spectrally complex dynamical phenomena. The CGPCM is a generative model in which white noise is passed through a causal, nonparametric-window moving-average filter, a construction that we show to be equivalent to ...
computer science
23,053
Kernel Recursive ABC: Point Estimation with Intractable Likelihood
stat.ML
We propose a novel approach to parameter estimation for simulator-based statistical models with intractable likelihoods. The proposed method is recursive application of kernel ABC and kernel herding to the same observed data. We provide a theoretical explanation regarding why this approach works, showing (for the popul...
computer science
23,054
Exact Sampling of Determinantal Point Processes without Eigendecomposition
stat.ML
Determinantal point processes (DPPs) enable the modelling of repulsion: they provide diverse sets of points. This repulsion is encoded in a kernel K that we can see as a matrix storing the similarity between points. The usual algorithm to sample DPPs is exact but it uses the spectral decomposition of K, a computation t...
computer science
23,055
Learning Weighted Representations for Generalization Across Designs
stat.ML
Predictive models that generalize well under distributional shift are often desirable and sometimes crucial to building robust and reliable machine learning applications. We focus on distributional shift that arises in causal inference from observational data and in unsupervised domain adaptation. We pose both of these...
computer science
23,056
Conditionally Independent Multiresolution Gaussian Processes
stat.ML
We propose a multiresolution Gaussian process (GP) model which assumes conditional independence among GPs across resolutions. We characterize each GP using a particular representation of the Karhunen-Lo\`eve expansion where each basis vector of the representation consists of an axis and a scale factor, referred to as t...
computer science
23,057
Tunability: Importance of Hyperparameters of Machine Learning Algorithms
stat.ML
Modern machine learning algorithms for classification or regression such as gradient boosting, random forest and neural networks involve a number of parameters that have to be fixed before running them. Such parameters are commonly denoted as hyperparameters in machine learning, a terminology we also adopt here. The te...
computer science
23,058
Learning Binary Latent Variable Models: A Tensor Eigenpair Approach
stat.ML
Latent variable models with hidden binary units appear in various applications. Learning such models, in particular in the presence of noise, is a challenging computational problem. In this paper we propose a novel spectral approach to this problem, based on the eigenvectors of both the second order moment matrix and t...
computer science
23,059
Application of Rényi and Tsallis Entropies to Topic Modeling Optimization
stat.ML
This is full length article (draft version) where problem number of topics in Topic Modeling is discussed. We proposed idea that Renyi and Tsallis entropy can be used for identification of optimal number in large textual collections. We also report results of numerical experiments of Semantic stability for 4 topic mode...
computer science
23,060
Computational Optimal Transport
stat.ML
Optimal Transport (OT) is a mathematical gem at the interface between probability, analysis and optimization. The goal of that theory is to define geometric tools that are useful to compare probability distributions. Earlier contributions originated from Monge's work in the 18th century, to be later rediscovered under ...
computer science
23,061
Kernel Embedding Approaches to Orbit Determination of Spacecraft Clusters
stat.ML
This paper presents a novel formulation and solution of orbit determination over finite time horizons as a learning problem. We present an approach to orbit determination under very broad conditions that are satisfied for n-body problems. These weak conditions allow us to perform orbit determination with noisy and high...
computer science
23,062
On Nonlinear Dimensionality Reduction, Linear Smoothing and Autoencoding
stat.ML
We develop theory for nonlinear dimensionality reduction (NLDR). A number of NLDR methods have been developed, but there is limited understanding of how these methods work and the relationships between them. There is limited basis for using existing NLDR theory for deriving new algorithms. We provide a novel framework ...
computer science
23,063
Bayesian Optimization for Dynamic Problems
stat.ML
We propose practical extensions to Bayesian optimization for solving dynamic problems. We model dynamic objective functions using spatiotemporal Gaussian process priors which capture all the instances of the functions over time. Our extensions to Bayesian optimization use the information learnt from this model to guide...
computer science
23,064
Provably robust estimation of modulo 1 samples of a smooth function with applications to phase unwrapping
stat.ML
Consider an unknown smooth function $f: [0,1]^d \rightarrow \mathbb{R}$, and say we are given $n$ noisy mod 1 samples of $f$, i.e., $y_i = (f(x_i) + \eta_i)\mod 1$, for $x_i \in [0,1]^d$, where $\eta_i$ denotes the noise. Given the samples $(x_i,y_i)_{i=1}^{n}$, our goal is to recover smooth, robust estimates of the cl...
computer science
23,065
Nonparametric Risk Assessment and Density Estimation for Persistence Landscapes
stat.ML
This paper presents approximate confidence intervals for each function of parameters in a Banach space based on a bootstrap algorithm. We apply kernel density approach to estimate the persistence landscape. In addition, we evaluate the quality distribution function estimator of random variables using integrated mean sq...
computer science
23,066
Variance Networks: When Expectation Does Not Meet Your Expectations
stat.ML
In this paper, we propose variance networks, a new model that stores the learned information in the variances of the network weights. Surprisingly, no information gets stored in the expectations of the weights, therefore if we replace these weights with their expectations, we would obtain a random guess quality predict...
computer science
23,067
Empirical bounds for functions with weak interactions
stat.ML
We provide sharp empirical estimates of expectation, variance and normal approximation for a class of statistics whose variation in any argument does not change too much when another argument is modified. Examples of such weak interactions are furnished by U- and V-statistics, Lipschitz L-statistics and various error f...
computer science
23,068
Variational Inference for Gaussian Process with Panel Count Data
stat.ML
We present the first framework for Gaussian-process-modulated Poisson processes when the temporal data appear in the form of panel counts. Panel count data frequently arise when experimental subjects are observed only at discrete time points and only the numbers of occurrences of the events between subsequent observati...
computer science
23,069
Learning unknown ODE models with Gaussian processes
stat.ML
In conventional ODE modelling coefficients of an equation driving the system state forward in time are estimated. However, for many complex systems it is practically impossible to determine the equations or interactions governing the underlying dynamics. In these settings, parametric ODE model cannot be formulated. Her...
computer science
23,070
Scalable Algorithms for Learning High-Dimensional Linear Mixed Models
stat.ML
Linear mixed models (LMMs) are used extensively to model dependecies of observations in linear regression and are used extensively in many application areas. Parameter estimation for LMMs can be computationally prohibitive on big data. State-of-the-art learning algorithms require computational complexity which depends ...
computer science
23,071
Simulation and Calibration of a Fully Bayesian Marked Multidimensional Hawkes Process with Dissimilar Decays
stat.ML
We propose a simulation method for multidimensional Hawkes processes based on superposition theory of point processes. This formulation allows us to design efficient simulations for Hawkes processes with differing exponentially decaying intensities. We demonstrate that inter-arrival times can be decomposed into simpler...
computer science
23,072
Optimal Transport for Multi-source Domain Adaptation under Target Shift
stat.ML
In this paper, we propose to tackle the problem of reducing discrepancies between multiple domains referred to as multi-source domain adaptation and consider it under the target shift assumption: in all domains we aim to solve a classification problem with the same output classes, but with labels' proportions differing...
computer science
23,073
SAM: Structural Agnostic Model, Causal Discovery and Penalized Adversarial Learning
stat.ML
We present the Structural Agnostic Model (SAM), a framework to estimate end-to-end non-acyclic causal graphs from observational data. In a nutshell, SAM implements an adversarial game in which a separate model generates each variable, given real values from all others. In tandem, a discriminator attempts to distinguish...
computer science
23,074
Variational zero-inflated Gaussian processes with sparse kernels
stat.ML
Zero-inflated datasets, which have an excess of zero outputs, are commonly encountered in problems such as climate or rare event modelling. Conventional machine learning approaches tend to overestimate the non-zeros leading to poor performance. We propose a novel model family of zero-inflated Gaussian processes (ZiGP) ...
computer science
23,075
Bucket Renormalization for Approximate Inference
stat.ML
Probabilistic graphical models are a key tool in machine learning applications. Computing the partition function, i.e., normalizing constant, is a fundamental task of statistical inference but it is generally computationally intractable, leading to extensive study of approximation methods. Iterative variational methods...
computer science
23,076
Uplift Modeling from Separate Labels
stat.ML
Uplift modeling is aimed at estimating the incremental impact of an action on an individual's behavior, which is useful in various application domains such as targeted marketing (advertisement campaigns) and personalized medicine (medical treatments). Conventional methods of uplift modeling require every instance to be...
computer science
23,077
Variational Message Passing with Structured Inference Networks
stat.ML
Recent efforts on combining deep models with probabilistic graphical models are promising in providing flexible models that are also easy to interpret. We propose a variational message-passing algorithm for variational inference in such models. We make three contributions. First, we propose structured inference network...
computer science
23,078
Estimation of lactate threshold with machine learning techniques in recreational runners
stat.ML
Lactate threshold is considered an essential parameter when assessing performance of elite and recreational runners and prescribing training intensities in endurance sports. However, the measurement of blood lactate concentration requires expensive equipment and the extraction of blood samples, which are inconvenient f...
computer science
23,079
Modelling sparsity, heterogeneity, reciprocity and community structure in temporal interaction data
stat.ML
We propose a novel class of network models for temporal dyadic interaction data. Our goal is to capture a number of important features often observed in social interactions: sparsity, degree heterogeneity, community structure and reciprocity. We propose a family of models based on self-exciting Hawkes point processes i...
computer science
23,080
Gaussian Processes indexed on the symmetric group: prediction and learning
stat.ML
In the framework of the supervised learning of a real function defined on a space X , the so called Kriging method stands on a real Gaussian field defined on X. The Euclidean case is well known and has been widely studied. In this paper, we explore the less classical case where X is the non commutative finite group of ...
computer science
23,081
A particle-based variational approach to Bayesian Non-negative Matrix Factorization
stat.ML
Bayesian Non-negative Matrix Factorization (NMF) is a promising approach for understanding uncertainty and structure in matrix data. However, a large volume of applied work optimizes traditional non-Bayesian NMF objectives that fail to provide a principled understanding of the non-identifiability inherent in NMF-- an i...
computer science
23,082
A Linear Shift Invariant Multiscale Transform
cs.CV
This paper presents a multiscale decomposition algorithm. Unlike standard wavelet transforms, the proposed operator is both linear and shift invariant. The central idea is to obtain shift invariance by averaging the aligned wavelet transform projections over all circular shifts of the signal. It is shown how the same t...
computer science
23,083
General Theory of Image Normalization
cs.CV
We give a systematic, abstract formulation of the image normalization method as applied to a general group of image transformations, and then illustrate the abstract analysis by applying it to the hierarchy of viewing transformations of a planar object.
computer science
23,084
A Differential Invariant for Zooming
cs.CV
This paper presents an invariant under scaling and linear brightness change. The invariant is based on differentials and therefore is a local feature. Rotationally invariant 2-d differential Gaussian operators up to third order are proposed for the implementation of the invariant. The performance is analyzed by simulat...
computer science
23,085
A Parallel Algorithm for Dilated Contour Extraction from Bilevel Images
cs.CV
We describe a simple, but efficient algorithm for the generation of dilated contours from bilevel images. The initial part of the contour extraction is explained to be a good candidate for parallel computer code generation. The remainder of the algorithm is of linear nature.
computer science
23,086
Image Compression with Iterated Function Systems, Finite Automata and Zerotrees: Grand Unification
cs.CV
Fractal image compression, Culik's image compression and zerotree prediction coding of wavelet image decomposition coefficients succeed only because typical images being compressed possess a significant degree of self-similarity. Besides the common concept, these methods turn out to be even more tightly related, to the...
computer science
23,087
Differential Invariants under Gamma Correction
cs.CV
This paper presents invariants under gamma correction and similarity transformations. The invariants are local features based on differentials which are implemented using derivatives of the Gaussian. The use of the proposed invariant representation is shown to yield improved correlation results in a template matching s...
computer science
23,088
Assisted Video Sequences Indexing : Motion Analysis Based on Interest Points
cs.CV
This work deals with content-based video indexing. Our viewpoint is semi-automatic analysis of compressed video. We consider the possible applications of motion analysis and moving object detection : assisting moving object indexing, summarising videos, and allowing image and motion queries. We propose an approach base...
computer science
23,089
Robustness of Regional Matching Scheme over Global Matching Scheme
cs.CV
The paper has established and verified the theory prevailing widely among image and pattern recognition specialists that the bottom-up indirect regional matching process is the more stable and the more robust than the global matching process against concentrated types of noise represented by clutter, outlier or occlusi...
computer science
23,090
Boosting the Differences: A fast Bayesian classifier neural network
cs.CV
A Bayesian classifier that up-weights the differences in the attribute values is discussed. Using four popular datasets from the UCI repository, some interesting features of the network are illustrated. The network is suitable for classification problems.
computer science
23,091
Distorted English Alphabet Identification : An application of Difference Boosting Algorithm
cs.CV
The difference-boosting algorithm is used on letters dataset from the UCI repository to classify distorted raster images of English alphabets. In contrast to rather complex networks, the difference-boosting is found to produce comparable or better classification efficiency on this complex problem.
computer science
23,092
Geometric Morphology of Granular Materials
cs.CV
We present a new method to transform the spectral pixel information of a micrograph into an affine geometric description, which allows us to analyze the morphology of granular materials. We use spectral and pulse-coupled neural network based segmentation techniques to generate blobs, and a newly developed algorithm to ...
computer science
23,093
Probabilistic Search for Object Segmentation and Recognition
cs.CV
The problem of searching for a model-based scene interpretation is analyzed within a probabilistic framework. Object models are formulated as generative models for range data of the scene. A new statistical criterion, the truncated object probability, is introduced to infer an optimal sequence of object hypotheses to b...
computer science
23,094
Least squares fitting of circles and lines
cs.CV
We study theoretical and computational aspects of the least squares fit (LSF) of circles and circular arcs. First we discuss the existence and uniqueness of LSF and various parametrization schemes. Then we evaluate several popular circle fitting algorithms and propose a new one that surpasses the existing methods in re...
computer science
23,095
Statistical efficiency of curve fitting algorithms
cs.CV
We study the problem of fitting parametrized curves to noisy data. Under certain assumptions (known as Cartesian and radial functional models), we derive asymptotic expressions for the bias and the covariance matrix of the parameter estimates. We also extend Kanatani's version of the Cramer-Rao lower bound, which he pr...
computer science
23,096
Flexible Camera Calibration Using a New Analytical Radial Undistortion Formula with Application to Mobile Robot Localization
cs.CV
Most algorithms in 3D computer vision rely on the pinhole camera model because of its simplicity, whereas virtually all imaging devices introduce certain amount of nonlinear distortion, where the radial distortion is the most severe part. Common approach to radial distortion is by the means of polynomial approximation,...
computer science
23,097
A New Analytical Radial Distortion Model for Camera Calibration
cs.CV
Common approach to radial distortion is by the means of polynomial approximation, which introduces distortion-specific parameters into the camera model and requires estimation of these distortion parameters. The task of estimating radial distortion is to find a radial distortion model that allows easy undistortion as w...
computer science
23,098
Rational Radial Distortion Models with Analytical Undistortion Formulae
cs.CV
The common approach to radial distortion is by the means of polynomial approximation, which introduces distortion-specific parameters into the camera model and requires estimation of these distortion parameters. The task of estimating radial distortion is to find a radial distortion model that allows easy undistortion ...
computer science
23,099
An Analytical Piecewise Radial Distortion Model for Precision Camera Calibration
cs.CV
The common approach to radial distortion is by the means of polynomial approximation, which introduces distortion-specific parameters into the camera model and requires estimation of these distortion parameters. The task of estimating radial distortion is to find a radial distortion model that allows easy undistortion ...
computer science
23,100
Camera Calibration: a USU Implementation
cs.CV
The task of camera calibration is to estimate the intrinsic and extrinsic parameters of a camera model. Though there are some restricted techniques to infer the 3-D information about the scene from uncalibrated cameras, effective camera calibration procedures will open up the possibility of using a wide range of existi...
computer science
23,101
A Family of Simplified Geometric Distortion Models for Camera Calibration
cs.CV
The commonly used radial distortion model for camera calibration is in fact an assumption or a restriction. In practice, camera distortion could happen in a general geometrical manner that is not limited to the radial sense. This paper proposes a simplified geometrical distortion modeling method by using two different ...
computer science