arXiv research

Proposes a Structural Matrix Autoregressive model for joint analysis of asset returns, realized volatility, and trading volume.

Novel estimation methods improve MAR model accuracy for high-dimensional time series.

Paper proposes LATC for multivariate time series prediction and missing data imputation.

Enhanced EEG classification using augmented covariance matrix.

New method for inferring network topology from partial data.

Paper proposes a new MAR model for global economic forecasting.

New method for identifying graph shift operators using vertex-time autoregressive models.

New method for estimating and testing impulse responses in high-dimensional VAR systems.

BiGG model efficiently generates sparse graphs with reduced complexity.

High-dimensional time series data exist in numerous areas such as finance, genomics, healthcare, and neuroscience. An unavoidable aspect of all such datasets is missing data, and dealing with this issue has been an important focus in statistics, control, and machine learning. In this work, we consider a high-dimensiona…

New GLS estimator handles high-dimensional data with autocorrelated errors.

We show Vector Autoregressive Moving Average models with scalar Moving Average components could be estimated by generalized least square (GLS) for each fixed moving average polynomial. The conditional variance of the GLS model is the concentrated covariant matrix of the moving average process. Under GLS the likelihood …

Spatial econometric research typically relies on the assumption that the spatial dependence structure is known in advance and is represented by a deterministic spatial weights matrix. Contrary to classical approaches, we investigate the estimation of sparse spatial dependence structures for regular lattice data. In par…

A new multivariate stochastic volatility estimation procedure for financial time series is proposed. A Wishart autoregressive process is considered for the volatility precision covariance matrix, for the estimation of which a two step procedure is adopted. The first step is the conditional inference on the autoregressi…

We show how to solve a number of problems in numerical linear algebra, such as least squares regression, $\ell_p$-regression for any $p \geq 1$, low rank approximation, and kernel regression, in time $T(A) \poly(\log(nd))$, where for a given input matrix $A \in \mathbb{R}^{n \times d}$, $T(A)$ is the time needed to com…

Linear attention in Transformers can be interpreted as dynamic VAR models.

Study on estimating sparse transition matrix of partially-observed VAR with noisy and sparse data.

We introduce a novel multivariate random process producing Bernoulli outputs per dimension, that can possibly formalize binary interactions in various graphical structures and can be used to model opinion dynamics, epidemics, financial and biological time series data, etc. We call this a Bernoulli Autoregressive Proces…

Tensor networks improve unsupervised learning performance.

Transformers become faster by linearizing self-attention.

We present a windowed technique to learn parsimonious time-varying autoregressive models from multivariate timeseries. This unsupervised method uncovers interpretable spatiotemporal structure in data via non-smooth and non-convex optimization. In each time window, we assume the data follow a linear model parameterized …

The vector autoregressive (VAR) model is a powerful tool in modeling complex time series and has been exploited in many fields. However, fitting high dimensional VAR model poses some unique challenges: On one hand, the dimensionality, caused by modeling a large number of time series and higher order autoregressive proc…

We study sparse principal component analysis for high dimensional vector autoregressive time series under a doubly asymptotic framework, which allows the dimension $d$ to scale with the series length $T$. We treat the transition matrix of time series as a nuisance parameter and directly apply sparse principal component…

Autoregressive sequence models achieve state-of-the-art performance in domains like machine translation. However, due to the autoregressive factorization nature, these models suffer from heavy latency during inference. Recently, non-autoregressive sequence models were proposed to reduce the inference time. However, the…

Non-autoregressive method speeds up protein folding prediction 23 times.

FLANDERS detects and blocks extreme model poisoning in federated learning.

Sparse Tucker decomposition with graph regularization improves time series forecasting accuracy.

A new method for filling in missing traffic data improves accuracy over existing techniques.

Paper unifies subspace identification and DMD for dynamical systems.

Survey of graph learning methods for combinatorial optimization problems.

New method identifies structural parameters without assuming uncorrelated errors.

StrNN uses neural network structures to learn conditional independencies.

Optimized variable orderings improve autoregressive model performance.

Vector autoregressive models characterize a variety of time series in which linear combinations of current and past observations can be used to accurately predict future observations. For instance, each element of an observation vector could correspond to a different node in a network, and the parameters of an autoregr…

The paper introduces a method to model error correlations in multivariate time series forecasting.

WAVE improves time series forecasting by integrating AR and MA components.

Missing value imputation is a fundamental problem in spatiotemporal modeling, from motion tracking to the dynamics of physical systems. Deep autoregressive models suffer from error propagation which becomes catastrophic for imputing long-range sequences. In this paper, we take a non-autoregressive approach and propose …

Improved covariance matrix forecasting for S&P 500 using factor models and shrinkage.

We introduce a concept of $autoregressive$ (AR)state-space realization that could be applied to all transfer functions $\boldsymbol{T}(L)$ with $\boldsymbol{T}(0)$ invertible. We show that a theorem of Kalman implies each Vector Autoregressive model (with exogenous variables) has a minimal $AR$-state-space realization …

We derive generalization error bounds for stationary univariate autoregressive (AR) models. We show that imposing stationarity is enough to control the Gaussian complexity without further regularization. This lets us use structural risk minimization for model selection. We demonstrate our methods by predicting interest…

Paper explores variable skipping to speed up range density estimation.

The paper introduces a dynamic MVP model using high-frequency financial data.

Autoregressive generative models of images tend to be biased towards capturing local structure, and as a result they often produce samples which are lacking in terms of large-scale coherence. To address this, we propose two methods to learn discrete representations of images which abstract away local detail. We show th…

FOCUS method forecasts counterfactuals in panel data with time series dynamics.

Flow-based generative models are a family of exact log-likelihood models with tractable sampling and latent-variable inference, hence conceptually attractive for modeling complex distributions. However, flow-based models are limited by density estimation performance issues as compared to state-of-the-art autoregressive…

New method makes machine learning approximations unbiased and efficient.

The problem of learning structural equation models (SEMs) from data is a fundamental problem in causal inference. We develop a new algorithm --- which is computationally and statistically efficient and works in the high-dimensional regime --- for learning linear SEMs from purely observational data with arbitrary noise …

The paper proposes autoregressive models for better offline RL.