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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.

168,657 papers · 148 categories

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48 results for Nonlinear Observations

New method identifies key genes affecting phenotypes in biological systems.

problem Identifying genes that drive specific phenotypes in complex biological systems.
method Data-driven observability decomposition using Koopman operators.
result Koopman operator representation identifies genes that drive phenotypes.

Detects model misspecifications in causal models using observational data.

problem Identifying predictor variables with causal effects in misspecified models.
method Develops a general framework based on observational data distribution and proposes an algorithm for finite sample data.
result Identifies predictor variables for causal effects even in misspecified models.

Study on conditioning Gaussian measures on nonlinear observations, including representer theorem and mode estimation.

problem Conditioning Gaussian measures on nonlinear observations in Bayesian inference and machine learning.
method Representer theorem, novel mode definition, maximum a posteriori estimation, Laplace approximation.
result Identification of infinite-dimensional Gaussian and finite-dimensional non-Gaussian components in conditioned measures.

Researchers identify latent variables and causal structures from nonlinear hierarchical models.

problem Challenging task of identifying latent variables and causal structures from observational data, especially when relationships are nonlinear.
method Investigated nonlinear latent hierarchical causal models, developed identification criterion, and constructed an estimation procedure.
result Identifiability of causal structures and latent variables achieved under mild assumptions.

Controller seeks informative system observations to predict nonlinear dynamics.

problem Predicting nonlinear dynamics with uncertain parameters.
method Expected free energy minimization for balancing goal state and informative observations.
result Controller improves performance in uncertain parameter scenarios.

New methods generalize nonlinear ICA beyond structural sparsity.

problem Identify true latent sources from nonlinear mixtures without structural sparsity assumptions.
method Propose identifiability results for undercomplete, partial sparsity, and flexible grouping structures.
result Prove identifiability in general settings of undercompleteness, partial sparsity, and flexible grouping structures.

New method recovers causal networks from short time-series data.

problem Inferring causal relationships from short time-series data in complex systems.
method Large-scale Nonlinear Granger Causality (lsNGC) approach.
result Captures meaningful interactions from limited observational data.

Filtering is a general name for inferring the states of a dynamical system given observations. The most common filtering approach is Gaussian Filtering (GF) where the distribution of the inferred states is a Gaussian whose mean is an affine function of the observations. There are two restrictions in this model: Gaussia…

2018-11-14abs ↗pdf ↗

Two algorithms for nonlinear systems with unknown inputs are compared and implemented.

problem Analysis and comparison of algorithms for nonlinear systems with unknown inputs.
method Two symbolic algorithms, ORC-DF and FISPO, are compared and implemented in a MATLAB toolbox.
result FISPO is more generally applicable, while ORC-DF is more efficient for affine input models.

DAISI improves data assimilation for complex systems with noisy observations.

problem Limited accuracy of classical DA methods in complex, nonlinear systems.
method Generative models with inverse sampling for flexible probabilistic inference.
result DAISI achieves accurate filtering results in challenging nonlinear systems.

KRCD detects unobserved confounders in nonlinear observational data.

problem Detecting unobserved confounders in nonlinear observational studies.
method Kernel Regression Confounder Detection (KRCD) using reproducing kernel Hilbert spaces.
result KRCD outperforms existing methods and achieves superior computational efficiency.

New method solves robust matrix completion using nonlinear equations.

problem Recover low rank and sparse matrices from incomplete observations.
method Transforms problem into solving a system of nonlinear equations, then uses the alternative direction method.
result Algorithm converges linearly to the true solution under proper assumptions.

Study tackles nonlinear factor models with unknown monotone links from incomplete and noisy data.

problem Learning nonlinear factor models with unknown monotone links from incomplete and noisy data.
method Formulated as joint recovery of low-rank factors, loadings, and nonlinear link function; proposed BCD algorithm with regularization.
result Established convergence guarantees and sublinear regret bounds for link-function updates.

The paper automates policy learning for nonlinear welfare criteria using machine learning and debiasing techniques.

problem Learning optimal policies from observational data with nonlinear welfare criteria.
method Modeling a nonlinear welfare criterion with a utility function, estimating propensity scores with machine learning, and using sieve approximations and cross-validation for model selection.
result The proposed policy learning method satisfies oracle inequalities, providing theoretical guarantees on performance.

New model combines ICA and HMM for unsupervised learning of nonstationary time series.

problem Manual segmentation of non-stationary data is computationally expensive and inaccurate.
method Combines Hidden Markov Model with nonlinear ICA for unsupervised learning.
result Proves identifiability of the model for general mixing nonlinearity.

Proposes FunNoL for better curve classification and reconstruction in multivariate functional data.

problem Linear methods fail to capture nonlinear structures in multivariate functional data.
method Functional nonlinear learning (FunNoL) method using nonlinear mapping.
result FunNoL outperforms FPCA in curve classification and reconstruction, especially in multivariate settings.

In this paper we study the problem of recovering a structured but unknown parameter θ{\bfθ}^* from nn nonlinear observations of the form yi=f(xi,θ)y_i=f(\langle {\bf{x}}_i,{\bfθ}^*\rangle) for i=1,2,,ni=1,2,\ldots,n. We develop a framework for characterizing time-data tradeoffs for a variety of parameter estimation algorithms when…

2016-10-23abs ↗pdf ↗

Proposes a new method for nonlinear Bayesian updates using ensemble kernel regression.

problem Nonlinear and non-Gaussian Bayesian updates for complex systems.
method Combines Kalman filtering for observed components and kernel density estimation for unobserved components, with subsampling and clustering.
result Reduces estimation errors in highly nonlinear scenarios compared to standard linear updates.

GD-VAEs learn dynamics from observations using geometric and topological information.

problem Learning parsimonious representations of nonlinear dynamics from observations.
method Develops data-driven methods incorporating geometric and topological information using Variational Autoencoders (VAEs).
result GD-VAEs provide methods for learning reduced dimensional representations of nonlinear dynamics.

New method recovers sparse signals from nonlinear observations with robust error bounds.

problem Recovering two sparse vectors from nonlinearly mixed observations with limited data.
method Regularization-based framework combining Huberized data fidelity and generalized folded-concave penalties with a proximal alternating algorithm.
result Estimation error bounds of order σslog(n)/mσ\sqrt{s\log(n)/m} at every localized stationary point, with oracle rate σs/mσ\sqrt{s/m} under beta-min condition.

This work uses a scalable approach to identify partially observed nonlinear systems.

problem Offline identification of partially observed nonlinear systems.
method Certainty-equivalent expectation-maximization (CEEM) as block coordinate-ascent.
result The CEEM approach can identify high-dimensional systems reliably and efficiently.

This paper contains the technical foundations from stochastic differential geometry for the construction of geometrically intrinsic nonlinear recursive filters. A diffusion X on a manifold N is run for a time interval T, with a random initial condition. There is a single observation consisting of a nonlinear function o…

1998-09-06abs ↗pdf ↗

Final part of a series on nonlinear observers on Riemannian metrics, establishing conditions for convergence.

problem Ensuring convergence of nonlinear observers on Riemannian metrics.
method Analyzing the nullity of the second fundamental form of the output function and its relationship to the infinite gain margin property.
result Formulated sufficient and necessary conditions for the nullity of the second fundamental form, linking it to the infinite gain margin property.

The paper analyzes the observability of relative pose estimation using dual quaternions.

problem Estimating relative pose in robotics applications.
method Lie algebraic nonlinear observability analysis on a dual quaternion system.
result Dual quaternion representation yields an observability matrix with a simple block triangular structure and full rank.

IMA addresses non-identifiability in nonlinear ICA by assuming orthogonal Jacobian columns.

problem Non-identifiability in nonlinear ICA.
method IMA assumes orthogonal Jacobian columns and extends to manifold settings.
result IMA circumvents non-identifiability issues and can be beneficial for higher-dimensional observations.

Learning nonlinear dynamics from diffusion data is a challenging problem since the individuals observed may be different at different time points, generally following an aggregate behaviour. Existing work cannot handle the tasks well since they model such dynamics either directly on observations or enforce the availabi…

2018-07-22abs ↗pdf ↗

Extends nonlinear filtering to predictable jump times.

problem Filtering with jumps in both signal and observation, especially when jump times are known.
method Derive Kushner-Stratonovich and Zakai equations for predictable discontinuities.
result Extends classical nonlinear filtering results to a setting with predictable discontinuities.

Interpretable framework evaluates structure learning methods for causal discovery from observational data.

problem Evaluation of structure learning methods under assumption violations in causal discovery.
method Six-dimensional evaluation metric (DOS) tailored for causal discovery.
result Amortized causal discovery delivers results with high proximity to the optimal solution.