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Yi Tian

10 accepted papers

2026

Object-Centric Alignment and Anchor Distillation for Weakly Supervised Referring Expression Comprehension

IJCAI 2026

Weakly supervised Referring Expression Comprehension (WREC) aims to localize referred objects using only image-text pairs without box-level annotations. Existing one-stage methods predominantly rely on anchor-level alignment, which suffers from two fundamental limitations: (1) anchors represent loca

Cited by 0Scholar
2023

Convex and Non-convex Optimization Under Generalized Smoothness

NeurIPS 2023spotlight

Classical analysis of convex and non-convex optimization methods often requires the Lipschitz continuity of the gradient, which limits the analysis to functions bounded by quadratics. Recent work relaxed this requirement to a non-uniform smoothness condition with the Hessian norm bounded by an affi…

Cited by 57SourcePDFScholar
2021

Complexity Lower Bounds for Nonconvex-Strongly-Concave Min-Max Optimization

NeurIPS 2021poster

We provide a first-order oracle complexity lower bound for finding stationary points of min-max optimization problems where the objective function is smooth, nonconvex in the minimization variable, and strongly concave in the maximization variable. We establish a lower bound of $\Omega\left(\sqrt{\k…

Cited by 52SourcePDFScholar
2021

Provably Efficient Algorithms for Multi-Objective Competitive RL

ICML 2021oral

We study multi-objective reinforcement learning (RL) where an agent’s reward is represented as a vector. In settings where an agent competes against opponents, its performance is measured by the distance of its average return vector to a target set. We develop statistically and computationally effic…

Cited by 28SourcePDFScholar
2020

Towards Minimax Optimal Reinforcement Learning in Factored Markov Decision Processes

NeurIPS 2020spotlight

We study minimax optimal reinforcement learning in episodic factored Markov decision processes (FMDPs), which are MDPs with conditionally independent transition components. Assuming the factorization is known, we propose two model-based algorithms. The first one achieves minimax optimal regret guara…

Cited by 29SourcePDFScholar
2018

Deep Progressive Reinforcement Learning for Skeleton-Based Action Recognition

CVPR 2018poster

In this paper, we propose a deep progressive reinforcement learning (DPRL) method for action recognition in skeleton-based videos, which aims to distil the most informative frames and discard ambiguous frames in sequences for recognizing actions. Since the choices of selecting representative frames…

Cited by 500SourcePDFScholar
2017

Learning a hierarchical spatio-temporal model for human activity recognition

ICASSP 2017accepted

Recent works have shown that hierarchical models lead to significant improvement in human activity recognition, which can not only enhance descriptive capability, but also improve discriminative power. However, most existing methods exploit just one of the two advantages. In this paper, a new hierar…

Cited by 0SourceScholar
2016

Benchmarking state-of-the-art visual saliency models for image quality assessment

ICASSP 2016accepted

A significant current research trend in image quality assessment is to investigate the added value of visual attention aspects. Previous approaches mainly focused on adopting a specific saliency model to improve a specific image quality metric (IQM). It is still not known yet which of the existing s…

Cited by 0SourceScholar