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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.

168,786 papers · 148 categories

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48 results for non-negative signals

Non-negative blind source separation (non-negative BSS), which is also referred to as non-negative matrix factorization (NMF), is a very active field in domains as different as astrophysics, audio processing or biomedical signal processing. In this context, the efficient retrieval of the sources requires the use of sig…

2014-07-29abs ↗pdf ↗

Nonnegative matrix factorization (NMF) factorizes a non-negative matrix into product of two non-negative matrices, namely a signal matrix and a mixing matrix. NMF suffers from the scale and ordering ambiguities. Often, the source signals can be monotonous in nature. For example, in source separation problem, the source…

2015-05-01abs ↗pdf ↗

Proposes a method to decompose multivariate signals into Gaussian components.

problem Decomposing multivariate signals into Gaussian components.
method Greedy variational method for non-negative multivariate signals as a weighted sum of Gaussians.
result Upper bound for the distance from any mode of a Gaussian mixture model to the set of corresponding means.

DI-sNMF uses data imputation to separate circumstellar signals in high contrast imaging.

problem Separating circumstellar signals from non-circumstellar signals in high contrast imaging.
method DI-sNMF converts the signal separation problem into a missing data problem, using non-negative matrix factorization to attribute PSF signals to regions flagged as missing data.
result DI-sNMF can precisely measure circumstellar objects without altering them, as shown in simulations and real GPI observations.

New method improves source separation using NMF and adversarial learning.

problem Source separation in single channel data.
method Maximum Discrepancy Generative Regularization applied to NMF.
result Improvement in reconstructed signals, especially in weak supervision scenarios.

NNK algorithm improves neighborhood and graph construction for machine learning.

problem Ad hoc selection of k and ε parameters in kNN and ε-neighborhood methods.
method NNK algorithm for better sparse signal approximation.
result NNK leads to superior performance in local neighborhood and graph-based machine learning tasks.

New weight initialisation for ICNNs accelerates learning and improves generalization.

problem Lack of effective initialisation strategies for ICNNs due to their unique weight and activation properties.
method Derived a principled weight initialisation by generalizing signal propagation theory for ICNNs with non-negative weights.
result Principled initialisation effectively accelerates learning and leads to better generalization in ICNNs.

Unified framework for structured principal subspace estimation with bounds and rates.

problem Structured principal subspace estimation problems.
method Unified framework, minimax lower and upper bounds, information-geometric complexity.
result Minimax rates of convergence for specific settings, including optimal rates for non-negative PCA/SVD.

Sparse coding--that is, modelling data vectors as sparse linear combinations of basis elements--is widely used in machine learning, neuroscience, signal processing, and statistics. This paper focuses on the large-scale matrix factorization problem that consists of learning the basis set, adapting it to specific data. V…

2009-08-01abs ↗pdf ↗

Brain networks in fMRI are typically identified using spatial independent component analysis (ICA), yet mathematical constraints such as sparse coding and positivity both provide alternate biologically-plausible frameworks for generating brain networks. Non-negative Matrix Factorization (NMF) would suppress negative BO…

2016-07-01abs ↗pdf ↗

Sharp inequality in spaces with non-negative Ricci curvature.

problem Proving a sharp isoperimetric inequality in metric measure spaces.
method Using volume entropy in non-compact metric measure spaces with non-negative synthetic Ricci curvature.
result Proved a sharp dimension-free isoperimetric inequality.

Non-negative curvature affects Markov chains' mixing and expansion properties.

problem Understanding the behavior of Markov chains with non-negative curvature.
method Analyzing conductance, displacement, and cutoff phenomenon in sparse Markov chains.
result Non-negatively curved Markov chains exhibit specific, non-standard behavior in terms of mixing and expansion.

In this paper we study non-negatively curved and rationally elliptic GKM4_4 manifolds and orbifolds. We show that their rational cohomology rings are isomorphic to the rational cohomology of certain model orbifolds. These models are quotients of isometric actions of finite groups on non-negatively curved torus orbifol…

2018-02-16abs ↗pdf ↗

Sharp inequality for submanifolds in manifolds with non-negative Ricci curvature.

problem Establishing a Fenchel-Willmore inequality for submanifolds in manifolds with non-negative Ricci curvature.
method Analyzing submanifolds in manifolds with non-negative intermediate Ricci curvature and Euclidean volume growth.
result Sharp Fenchel-Willmore inequality for submanifolds in manifolds with non-negative intermediate Ricci curvature.

The paper proves conjectures and classifies metrics on 3D manifolds.

problem Proving conjectures and classifying metrics on 3D manifolds with specific curvature conditions.
method Analytical proofs and classification theorems.
result Critical metrics on 3D manifolds are isometric to geodesic balls in space forms.

Survey on rigidity and almost rigidity of Green functions in non-negative Ricci curvature spaces.

problem Rigidity and almost rigidity of Green functions in non-negative Ricci curvature spaces.
method Survey and observation on Cheeger-Yau inequality on RCD spaces.
result Observations on the Cheeger-Yau inequality and its applications.

We prove that if a closed, smooth, simply-connected 4-manifold with a circle action admits an almost non-negatively curved sequence of invariant Riemannian metrics, then it also admits a non-negatively curved Riemannian metric invariant with respect to the same action. The same is shown for torus actions of higher rank…

2019-07-15abs ↗pdf ↗

Upper bounds on Laplacian eigenvalues on manifolds with non-negative curvature.

problem Bounding Laplacian eigenvalues on manifolds with non-negative scalar curvature.
method Investigation of invariant spectrum on compact Riemannian manifolds with large isometry groups.
result Upper bounds for eigenvalues of the invariant spectrum assuming non-negative scalar curvature.

Deep-neural-network (DNN) based noise suppression systems yield significant improvements over conventional approaches such as spectral subtraction and non-negative matrix factorization, but do not generalize well to noise conditions they were not trained for. In comparison to DNNs, humans show remarkable noise suppress…

2018-06-01abs ↗pdf ↗

Paper proves edge-connectivity equals minimum degree for graphs with non-negative curvature.

problem Edge-connectivity vs. minimum degree in graphs with non-negative curvature.
method Analyzes finite connected graphs with non-negative Lin-Lu-Yau curvature.
result Edge-connectivity equals minimum degree for graphs with non-negative curvature.