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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,742 papers · 148 categories

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3637261,0891,452 · Jun 202019922001200920172026
48 results for unsupervised mixture models

A new method detects outliers using ensembles of Dirichlet process mixtures.

problem Challenges in unsupervised outlier detection using Dirichlet process mixtures.
method Ensembles of Dirichlet process Gaussian mixtures with random subspace and subsampling.
result Empirically outperforms existing approaches in unsupervised outlier detection.

This paper develops a federated EM algorithm for unsupervised learning of mixture models.

problem Theoretical foundations of unsupervised federated learning are lacking.
method Introduces a federated gradient EM algorithm (FedGrEM) for unsupervised learning of mixture models.
result Theoretical analysis shows FedGrEM outperforms local single-task learning.

TAMD prevents degeneracy in finite mixtures, offering strong guarantees but modest practical improvements.

problem Degeneracy in maximum likelihood estimation of finite mixtures.
method Transcendental regularization with analytic barrier functions.
result Strong theoretical guarantees (identifiability, consistency, robustness) but modest practical improvements.

A faster EM algorithm for unsupervised Gaussian mixture models.

problem Efficiently determining the number of components in Gaussian mixture models.
method Adaptive Anderson Acceleration (AA) for EM algorithm, with novel monotonicity control and covariance matrix preservation.
result Significantly faster convergence compared to non-accelerated EM, up to 60X in some cases.

New GMM models fit high-dimensional data with fewer parameters.

problem Overparameterization and lack of flexibility in GMMs for high-dimensional data.
method Piecewise-constant covariance eigenvalue profiles, EM and penalized EM algorithms.
result Superior likelihood-parsimony tradeoffs in density fitting, clustering, and denoising.

The Adversarially Learned Mixture Model (AMM) is a generative model for unsupervised or semi-supervised data clustering. The AMM is the first adversarially optimized method to model the conditional dependence between inferred continuous and categorical latent variables. Experiments on the MNIST and SVHN datasets show t…

2018-07-14abs ↗pdf ↗

Finite mixtures of regression models offer a flexible framework for investigating heterogeneity in data with functional dependencies. These models can be conveniently used for unsupervised learning on data with clear regression relationships. We extend such models by imposing an eigen-decomposition on the multivariate …

2013-12-02abs ↗pdf ↗

Unsupervised clustering is one of the most fundamental challenges in machine learning. A popular hypothesis is that data are generated from a union of low-dimensional nonlinear manifolds; thus an approach to clustering is identifying and separating these manifolds. In this paper, we present a novel approach to solve th…

2017-12-21abs ↗pdf ↗

CADGMM detects anomalies by capturing complex correlations in data.

problem Detecting anomalies in complex, unstructured data.
method CADGMM uses a graph structure to encode correlations, then a dual-encoder to learn low-dimensional latent space, followed by a Gaussian Mixture Model for anomaly detection.
result CADGMM effectively detects anomalies in real-world datasets.

Transformers can cluster data from Gaussian mixtures without supervision.

problem Clustering data from Gaussian mixtures without labeled data.
method Theoretical analysis of attention-based layers, focusing on a simplified two-head attention layer and an identity matrix attention layer.
result Attention-based layers can align with true mixture centroids and adapt to input-specific distributions.

Study improves GMM learning performance through multi-task and transfer learning.

problem Improving GMM learning performance through similar task structures.
method Proposes a multi-task GMM learning procedure based on EM algorithm, robust to outliers.
result Achieves minimax optimal rate of convergence for parameter estimation and mis-clustering.

InClass nets use neural networks to estimate CIMMs without assuming fixed parameters.

problem Nonparametric estimation of conditional independence mixture models.
method Independent classifier neural networks (NNs) for multi-class classification.
result Nonparametric identifiability conditions for bivariate CIMMs.

Mixture models are a fundamental tool in applied statistics and machine learning for treating data taken from multiple subpopulations. The current practice for estimating the parameters of such models relies on local search heuristics (e.g., the EM algorithm) which are prone to failure, and existing consistent methods …

2012-03-03abs ↗pdf ↗

A new clustering framework using fixed points for data analysis.

problem Lack of unified understanding and application of clustering algorithms in data analysis.
method Restated model-based clustering using fixed point theory, iteratively constructing contraction maps to find cluster centers.
result Unified clustering framework reveals convergence mechanisms and interconnections among clustering algorithms.

We consider unsupervised estimation of mixtures of discrete graphical models, where the class variable corresponding to the mixture components is hidden and each mixture component over the observed variables can have a potentially different Markov graph structure and parameters. We propose a novel approach for estimati…

2012-03-04abs ↗pdf ↗

Paper establishes universal lower bounds and optimal rates for clustering sub-exponential mixture models.

problem Achieving optimal error rates in clustering sub-exponential mixture models.
method Establishes universal lower bounds and demonstrates iterative algorithms' optimality in sub-exponential mixture models.
result Iterative algorithms achieve the universal lower bound in sub-exponential mixture models.

This work studies the class of algorithms for learning with side-information that emerge by extending generative models with embedded context-related variables. Using finite mixture models (FMM) as the prototypical Bayesian network, we show that maximum-likelihood estimation (MLE) of parameters through expectation-maxi…

2015-07-29abs ↗pdf ↗

Semi-supervised learning can't outperform supervised learning for 2-Gaussian mixture models.

problem Can semi-supervised learning algorithms improve over supervised learning?
method Deriving a tight lower bound for 2-Gaussian mixture models.
result No SSL algorithm can improve upon the minimax-optimal statistical error rates of supervised or unsupervised learning for these distributions.

Bayesian method estimates contamination factor for unsupervised anomaly detection.

problem No good methods for estimating contamination factor in unsupervised anomaly detection.
method Bayesian approach using mixture formulation of anomaly detector outputs.
result Estimated contamination factor distribution is well-calibrated and improves anomaly detection performance.

We assume that a high-dimensional datum, like an image, is a compositional expression of a set of properties, with a complicated non-linear relationship between the datum and its properties. This paper proposes a factorial mixture prior for capturing latent properties, thereby adding structured compositionality to deep…

2018-12-18abs ↗pdf ↗

A new method uncovers discrete and continuous factors in gene expression data.

problem Jointly identifying discrete and continuous factors of variability without supervision.
method cpl-mixVAE framework using multiple interacting networks.
result The method successfully uncovers discrete and continuous factors in gene expression data.

A robust loss for anomaly mitigation and unsupervised contamination classification

problem Detecting and mitigating contamination in supervised and unsupervised settings
method Neural Bayesian Anomaly Mitigation (NBAM)
result Recovering the structure of contamination and identifying label-flip pairs

We present a probabilistic model for unsupervised alignment of high-dimensional time-warped sequences based on the Dirichlet Process Mixture Model (DPMM). We follow the approach introduced in (Kazlauskaite, 2018) of simultaneously representing each data sequence as a composition of a true underlying function and a time…

2018-11-26abs ↗pdf ↗

Outcome regressed on class labels identified by unsupervised clustering is custom in many applications. However, it is common to ignore the misclassification of class labels caused by the learning algorithm, which potentially leads to serious bias of the estimated effect parameters. Due to its generality we suggest to …

2019-08-16abs ↗pdf ↗

New method improves anomaly detection in acoustic signals.

problem Poor anomaly detection performance in existing acoustic signal-based unsupervised methods.
method Deep autoencoding Gaussian mixture model with hyper-parameter optimization.
result Significantly improved anomaly detection performance compared to previous methods.

A fast method estimates Gaussian mixture components without iterative fitting.

problem Estimating the number of components in high-dimensional Gaussian mixtures.
method Center data, compute singular values, and count above a threshold.
result The estimator consistently recovers the true number of components under mild separation condition.

SPACE models complex scenes by decomposing objects and backgrounds.

problem Scalability and unsupervised object-oriented scene representation learning.
method Generative latent variable model combining spatial-attention and scene-mixture approaches.
result SPACE achieves factorized object representations and decomposes complex scenes.