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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.

169,181 papers · 148 categories

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48 results for complex-valued nonlinear filtering

Proposes random Euler filters for efficient complex-valued nonlinear signal processing.

problem Efficiently processing complex-valued nonlinear signals with reduced computational cost.
method Introduces linear and widely-linear random Euler complex-valued filters with fixed network structures.
result Analytical minimum mean square error and optimum step-size derived for transient and steady-state performances.

A complex-valued convolutional network (convnet) implements the repeated application of the following composition of three operations, recursively applying the composition to an input vector of nonnegative real numbers: (1) convolution with complex-valued vectors followed by (2) taking the absolute value of every entry…

2015-03-11abs ↗pdf ↗

A new method for complex-valued signals improves convergence and performance.

problem Nonlinear channel equalization and complex-valued signals with different properties.
method Generalized complex kernel least-mean-square (gCKLMS) algorithm.
result The gCKLMS algorithm converges faster and performs better than previous methods.

Complex-valued neural networks improve seismic data analysis by preserving phase information.

problem Low-frequency aliasing in seismic data due to discarded phase information.
method Developed complex-valued deep convolutional networks to leverage phase information in deterministic physical data.
result Complex-valued networks outperform real-valued networks in training and inference from deterministic physical data.

CLCNet improves noise reduction in hearing aids with deep learning.

problem Noise reduction in hearing aids is challenging due to real-time and frequency resolution constraints.
method Proposes CLCNet, a deep learning framework based on complex linear coding.
result CLCNet outperforms traditional methods in noisy environments.

Complex-valued signals are used in the modeling of many systems in engineering and science, hence being of fundamental interest. Often, random complex-valued signals are considered to be proper. A proper complex random variable or process is uncorrelated with its complex conjugate. This assumption is a good model of th…

2015-02-17abs ↗pdf ↗

EnSF improves accuracy in tracking high-dimensional nonlinear systems.

problem Low accuracy in high-dimensional, nonlinear filtering problems.
method Score-based diffusion model, mini-batch Monte Carlo estimator.
result EnSF outperforms state-of-the-art methods in tracking high-dimensional systems.

Proposes a new filtering method for dynamical systems that relaxes Gaussian and affine assumptions.

problem Inferring states of dynamical systems from observations with Gaussian and affine assumptions.
method Relaxes Gaussian and affine assumptions using deep, nonlinear, non-Gaussian models.
result Significant advantage over Gaussian Filtering and nonlinear fixed kernels.

New method improves nonlinear filtering accuracy with reduced computation.

problem Complex nonlinear filtering with small system noise.
method Asymptotic expansion with ordinary differential equations and Edgeworth-type correction.
result Significantly lower computational cost with improved accuracy.

Novel filtering method for high-dimensional chaotic systems.

problem Filtering in high-dimensional non-Gaussian models with chaotic dynamics and sparse observations.
method Transportation of measures, convex optimization, probabilistic graphical models, nonlinear couplings.
result State-of-the-art tracking performance on chaotic systems like Lorenz-96 model.

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.

This study improves state estimation for nonlinear systems using conditional normalizing flows.

problem Performance degradation of traditional filtering algorithms in nonlinear systems with non-Gaussian uncertainty.
method Uses conditional normalizing flows with MLP, transformer, or state-space models for state and parameter estimation.
result Optimal-transport-inspired kinetic loss mitigates overparameterization in flows.

A new flow-based Bayesian filter tackles high-dimensional nonlinear stochastic systems.

problem Bayesian filtering for high-dimensional nonlinear systems is challenging due to non-Gaussian distributions and computational limitations.
method Integrates normalizing flows to construct a latent linear state-space model with efficient density estimation and sampling.
result Demonstrates superior accuracy and efficiency in numerical experiments.

We consider the nonlinear Kalman filtering problem using Kullback-Leibler (KL) and αα-divergence measures as optimization criteria. Unlike linear Kalman filters, nonlinear Kalman filters do not have closed form Gaussian posteriors because of a lack of conjugacy due to the nonlinearity in the likelihood. In this paper …

2017-05-01abs ↗pdf ↗

A new method improves Bayesian filtering in nonlinear systems.

problem Bayesian filtering in nonlinear dynamical systems with non-Gaussian posteriors.
method Transport maps with block-triangular structure and gradient flows for MMD minimization.
result Accurate approximation of non-Gaussian posteriors without particle collapse.

Bayesian filtering approach identifies nonlinear restoring forces in dynamic systems.

problem Identification of nonlinear dynamic systems in engineering.
method Modeling the nonlinear restoring force as a Gaussian process, converting it to a state-space model, and inferring internal states and the nonlinear restoring force through filtering and smoothing.
result The approach effectively identifies nonlinear restoring forces in both simulated and experimental datasets.

We define a class of geometric flows on a complete Kähler manifold to unify some physical and mechanical models such as the motion equations of vortex filament, complex-valued mKdV equations, derivative nonlinear Schrödinger equations etc. Furthermore, we consider the existence for these flows from S1S^1 into a complet…

2012-03-02abs ↗pdf ↗

Proposes a new complex Gaussian distribution for better modeling of complex-valued signals.

problem Limited ability of Gaussian distribution to represent diverse amplitude characteristics.
method Introduces a power-weighted noncentral complex Gaussian distribution on the complex plane.
result Consistently outperforms conventional distributions in log-likelihood for speech power spectra.

Kernel-based Bayesian filter for nonlinear systems using infinite-dimensional operators.

problem Modeling and predicting nonlinear dynamical systems.
method Functional Bayesian perspective, reproducing kernel Hilbert space, Gaussian kernel.
result Effective approximation and accurate results for nonlinear systems.

A new numerical scheme approximates nonlinear filtering densities for noisy and partial measurements.

problem Approximating nonlinear filtering densities for noisy and partial measurements.
method Deep splitting scheme applied to the Fokker--Planck equation followed by Bayes' formula.
result Convergence rate established for the numerical scheme under parabolic Hörmander condition.

Kähler information manifolds for signal filters in weighted Hardy spaces are explored.

problem Developing a geometric framework for signal processing filters in weighted Hardy spaces.
method Introducing weighted Hardy spaces and smooth transformations of transfer functions, demonstrating the Kähler manifold structure.
result The Riemannian geometry of weighted Hardy norms for transfer functions forms a Kähler manifold.

A new SOHP filter improves trend estimation in economic time series.

problem Improving trend estimation in nonlinear economic time series.
method Recursive application of one-sided HP filter on updated cyclical components, combined with an incremental HP filtering algorithm.
result Better performance of SOHP filter compared to other HP-type filters on real economic data.

MASF improves score-based filters for high-dimensional nonlinear systems with spatially sparse measurements.

problem Challenges in data assimilation for nonlinear, high-dimensional systems with spatially sparse measurements.
method Developed a forward process tailored for filtering that transforms the system state toward the measurement space, enabling a theoretically sound formulation of the likelihood score.
result MASF shows improved performance over existing score-based filters and ensemble-type Kalman filters, achieving up to a 28.2× wall-clock speedup.

Develops a fast and precise method to evaluate likelihood of jump-diffusion models.

problem Evaluating likelihood functions of models with stochastic volatility and jumps.
method Deterministic nonlinear filtering algorithm based on Kitagawa's method.
result Deterministic filtering is faster and more precise than particle filter.

A new ML-based filter improves data assimilation for nonlinear systems.

problem Improving data assimilation for nonlinear systems using ensemble methods.
method Developed a machine learning-based conditional mean filter (ML-EnCMF) integrating ANN and linear functions.
result ML-EnCMF outperforms EnKF and likelihood-based EnCMF in nonlinear systems.

The paper develops a computational method for efficient online filtering of diffusion processes.

problem Online filtering of discretely observed nonlinear diffusion processes.
method The approach involves Doob's hh-transforms approximated by solving backward Kolmogorov equations using nonlinear Feynman-Kac formulas and neural networks.
result The proposed method can be orders of magnitude more efficient than state-of-the-art particle filters.

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.

This work preserves linear invariants in ensemble filters for non-Gaussian data assimilation.

problem Maintaining critical invariants like mass, stoichiometric balance, and charge in non-Gaussian data assimilation.
method Introducing a novel class of nonlinear ensemble filters using measure transport theory.
result Recovery of a constrained Kalman filter for Gaussian settings and combination with regularization techniques.

A new method for estimating adversarial strategies in nonlinear systems.

problem Inferring an intelligent adversarial agent's strategy in highly nonlinear systems.
method Formulated inverse cognition as a nonlinear Gaussian state-space model and developed an inverse UKF (IUKF) system.
result The estimation error of IUKF converges and closely follows the recursive Cramér-Rao lower bound.

This paper presents an exclusive classification of the largest crashes in Dow Jones Industrial Average (DJIA), SP500 and NASDAQ in the past century. Crashes are objectively defined as the top-rank filtered drawdowns (loss from the last local maximum to the next local minimum disregarding noise fluctuations), where the …

2004-01-13abs ↗pdf ↗

Complex-valued neural networks perform similarly to real-valued models for real-valued classification tasks.

problem Comparing real-valued and complex-valued neural networks for real-valued classification tasks.
method Comparison of neural networks with similar capacity sizes, using various activation functions and weight initialisation strategies.
result Complex-valued neural networks perform equal to or slightly worse than real-valued models for real-valued classification tasks.