Search Results for author: Xu Cai

Found 7 papers, 1 papers with code

Kernelized Normalizing Constant Estimation: Bridging Bayesian Quadrature and Bayesian Optimization

no code implementations11 Jan 2024 Xu Cai, Jonathan Scarlett

In this paper, we study the problem of estimating the normalizing constant $\int e^{-\lambda f(x)}dx$ through queries to the black-box function $f$, where $f$ belongs to a reproducing kernel Hilbert space (RKHS), and $\lambda$ is a problem parameter.

Bayesian Optimization

On Average-Case Error Bounds for Kernel-Based Bayesian Quadrature

no code implementations22 Feb 2022 Xu Cai, Chi Thanh Lam, Jonathan Scarlett

In this paper, we study error bounds for {\em Bayesian quadrature} (BQ), with an emphasis on noisy settings, randomized algorithms, and average-case performance measures.

Transient Synchronization Stability Analysis of Wind Farms with MMC-HVDC Integration Under Offshore AC Grid Fault

no code implementations25 Oct 2021 Yu Zhang, Chen Zhang, Renxin Yang, Jing Lyu, Li Liu, Xu Cai

The MMC-HVDC connected offshore wind farms (OWFs) could suffer short circuit fault (SCF), whereas their transient stability is not well analysed.

Large-Signal Grid-Synchronization Stability Analysis of PLL-based VSCs Using Lyapunov's Direct Method

no code implementations23 May 2021 Yu Zhang, Chen Zhang, Xu Cai

Grid-synchronization stability (GSS) is an emerging stability issue of grid-tied voltage source converters (VSCs), which can be provoked by severe grid voltage sags.

Lenient Regret and Good-Action Identification in Gaussian Process Bandits

1 code implementation11 Feb 2021 Xu Cai, Selwyn Gomes, Jonathan Scarlett

In this paper, we study the problem of Gaussian process (GP) bandits under relaxed optimization criteria stating that any function value above a certain threshold is "good enough".

On Lower Bounds for Standard and Robust Gaussian Process Bandit Optimization

no code implementations20 Aug 2020 Xu Cai, Jonathan Scarlett

In a robust setting in which every sampled point may be perturbed by a suitably-constrained adversary, we provide a novel lower bound for deterministic strategies, demonstrating an inevitable joint dependence of the cumulative regret on the corruption level and the time horizon, in contrast with existing lower bounds that only characterize the individual dependencies.

FRAME Revisited: An Interpretation View Based on Particle Evolution

no code implementations4 Dec 2018 Xu Cai, Yang Wu, Guanbin Li, Ziliang Chen, Liang Lin

FRAME (Filters, Random fields, And Maximum Entropy) is an energy-based descriptive model that synthesizes visual realism by capturing mutual patterns from structural input signals.

Descriptive

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