Search Results for author: Wai Ming Tai

Found 11 papers, 2 papers with code

Optimal estimation of Gaussian (poly)trees

1 code implementation9 Feb 2024 Yuhao Wang, Ming Gao, Wai Ming Tai, Bryon Aragam, Arnab Bhattacharyya

We develop optimal algorithms for learning undirected Gaussian trees and directed Gaussian polytrees from data.

Inconsistency of cross-validation for structure learning in Gaussian graphical models

no code implementations28 Dec 2023 Zhao Lyu, Wai Ming Tai, Mladen Kolar, Bryon Aragam

In this paper, we highlight the inherent limitations of cross-validation when employed to discern the structure of a Gaussian graphical model.

Model Selection

On Mergable Coresets for Polytope Distance

no code implementations8 Nov 2023 Benwei Shi, Aditya Bhaskara, Wai Ming Tai, Jeff M. Phillips

We show that a constant-size constant-error coreset for polytope distance is simple to maintain under merges of coresets.

Learning Mixtures of Gaussians with Censored Data

no code implementations6 May 2023 Wai Ming Tai, Bryon Aragam

We study the problem of learning mixtures of Gaussians with censored data.

Tight Bounds on the Hardness of Learning Simple Nonparametric Mixtures

no code implementations28 Mar 2022 Bryon Aragam, Wai Ming Tai

Combining these bounds, we conclude that the optimal sample complexity of this problem properly lies in between polynomial and exponential, which is not common in learning theory.

Density Estimation Learning Theory

Optimal estimation of Gaussian DAG models

1 code implementation25 Jan 2022 Ming Gao, Wai Ming Tai, Bryon Aragam

In other words, at least for Gaussian models with equal error variances, learning a directed graphical model is statistically no more difficult than learning an undirected graphical model.

Optimal Coreset for Gaussian Kernel Density Estimation

no code implementations15 Jul 2020 Wai Ming Tai

We study how to construct a small subset $Q$ of $P$ such that the kernel density estimate of $P$ is approximated by the kernel density estimate of $Q$.

Density Estimation

Approximate Guarantees for Dictionary Learning

no code implementations28 May 2019 Aditya Bhaskara, Wai Ming Tai

The problem is formalized as factorizing a matrix $X (d \times n)$ (whose columns are the signals) as $X = AY$, where $A$ has a prescribed number $m$ of columns (typically $m \ll n$), and $Y$ has columns that are $k$-sparse (typically $k \ll d$).

Dictionary Learning

The GaussianSketch for Almost Relative Error Kernel Distance

no code implementations9 Nov 2018 Jeff M. Phillips, Wai Ming Tai

We introduce two versions of a new sketch for approximately embedding the Gaussian kernel into Euclidean inner product space.

Near-Optimal Coresets of Kernel Density Estimates

no code implementations6 Feb 2018 Jeff M. Phillips, Wai Ming Tai

When $d\geq 1/\varepsilon^2$, it is known that the size of coreset can be $O(1/\varepsilon^2)$.

Improved Coresets for Kernel Density Estimates

no code implementations11 Oct 2017 Jeff M. Phillips, Wai Ming Tai

When the dimension $d$ is constant, we demonstrate much tighter bounds on the size of the coreset specifically for Gaussian kernels, showing that it is bounded by the size of the coreset for axis-aligned rectangles.

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