← Search

Zhitang Chen

21 accepted papers

2026

A²Flow: Automating Agentic Workflow Generation via Self-Adaptive Abstraction Operators

AAAI 2026technical

Large language models (LLMs) have shown strong potential in automating the design of agentic workflows. However, existing methods still rely heavily on manually predefined operators, limiting generalization and scalability. To address this issue, we propose A²Flow, a fully automated framework for ag

Cited by 0SourcePDFScholar
2026

Boosting Cross-problem Generalization in Diffusion-Based Neural Combinatorial Solver via Inference Time Adaptation

AAAI 2026technical

Diffusion-based Neural Combinatorial Optimization (NCO) has demonstrated effectiveness in solving NP-complete (NPC) problems by learning discrete diffusion models for solution generation, eliminating hand-crafted domain knowledge. Despite their success, existing NCO methods face significant challeng

Cited by 0SourcePDFScholar
2026

Hista and Numca: Estimate State Value Effectively for Large Language Model Reinforcement Learning

ICML 2026spotlight

Reinforcement Learning (RL) refines large language models (LLMs) by directly optimizing model behavior with reward signals. Although accurate state value estimation is essential for stable training in classical RL settings, it remains an understudied challenge in LLM post-training. In this work, we …

Cited by 0SourceScholar
2025

Proximalized Preference Optimization for Diverse Feedback Types: A Decomposed Perspective on DPO

NeurIPS 2025poster

Direct alignment methods typically train large language models (LLMs) by contrasting the likelihoods of preferred and dispreferred responses. While effective for matching relative preferences, these methods have been widely observed to depress the absolute likelihoods of example responses. Consequen…

Cited by 0SourceScholar
2024

Sampling is as easy as keeping the consistency: convergence guarantee for Consistency Models

ICML 2024poster

We provide the first convergence guarantee for the Consistency Models (CMs), a newly emerging type of one-step generative models that is capable of generating comparable samples to those sampled from state-of-the-art Diffusion Models. Our main result is that, under the basic assumptions on score-mat…

Cited by 2SourcePDFScholar
2023

Efficient Robust Bayesian Optimization for Arbitrary Uncertain inputs

NeurIPS 2023poster

Bayesian Optimization (BO) is a sample-efficient optimization algorithm widely employed across various applications. In some challenging BO tasks, input uncertainty arises due to the inevitable randomness in the optimization process, such as machining errors, execution noise, or contextual variabili…

Cited by 1SourcePDFScholar
2023

FastGR: Global Routing on CPU-GPU with Heterogeneous Task Graph Scheduler (Extended Abstract)

IJCAI 2023poster

Running time is a key metric across the standard physical design flow stages. However, with the rapid growth in design sizes, routing runtime has become the runtime bottleneck in the physical design flow. To improve the effectiveness of the modern global router, we propose a global routing framework…

Cited by 0SourcePDFScholar
2023

Neighbor Auto-Grouping Graph Neural Networks for Handover Parameter Configuration in Cellular Network

AAAI 2023technical

The mobile communication enabled by cellular networks is the one of the main foundations of our modern society. Optimizing the performance of cellular networks and providing massive connectivity with improved coverage and user experience has a considerable social and economic impact on our daily lif…

Cited by 0SourcePDFScholar
2022

Out-of-Distribution Generalization With Causal Invariant Transformations

CVPR 2022poster

In real-world applications, it is important and desirable to learn a model that performs well on out-of-distribution (OOD) data. Recently, causality has become a powerful tool to tackle the OOD generalization problem, with the idea resting on the causal mechanism that is invariant across domains of…

Cited by 80PDFScholar
2022

Para-CFlows: $C^k$-universal diffeomorphism approximators as superior neural surrogates

NeurIPS 2022accept

Invertible neural networks based on Coupling Flows (CFlows) have various applications such as image synthesis and data compression. The approximation universality for CFlows is of paramount importance to ensure the model expressiveness. In this paper, we prove that CFlows}can approximate any diffeom…

Cited by 7SourcePDFScholar
2022

Reframed GES with a neural conditional dependence measure

UAI 2022poster

In a nonparametric setting, the causal structure is often identifiable only up to Markov equivalence, and for the purpose of causal inference, it is useful to learn a graphical representation of the Markov equivalence class (MEC). In this paper, we revisit the Greedy Equivalence Search (GES) algori…

2021

CausalVAE: Disentangled Representation Learning via Neural Structural Causal Models

CVPR 2021poster

Learning disentanglement aims at finding a low dimensional representation which consists of multiple explanatory and generative factors of the observational data. The framework of variational autoencoder (VAE) is commonly used to disentangle independent factors from observations. However, in real sc…

Cited by 337PDFScholar
2021

Ordering-Based Causal Discovery with Reinforcement Learning

IJCAI 2021poster

It is a long-standing question to discover causal relations among a set of variables in many empirical sciences. Recently, Reinforcement Learning (RL) has achieved promising results in causal discovery from observational data. However, searching the space of directed graphs and enforcing acyclic…

2019

Universal Hypothesis Testing with Kernels: Asymptotically Optimal Tests for Goodness of Fit

AISTATS 2019poster

We characterize the asymptotic performance of nonparametric goodness of fit testing. The exponential decay rate of the type-II error probability is used as the asymptotic performance metric, and a test is optimal if it achieves the maximum rate subject to a constant level constraint on the type-I er…

Cited by 7SourcePDFScholar
2018

Causal Inference and Mechanism Clustering of A Mixture of Additive Noise Models

NeurIPS 2018poster

The inference of the causal relationship between a pair of observed variables is a fundamental problem in science, and most existing approaches are based on one single causal model. In practice, however, observations are often collected from multiple sources with heterogeneous causal models due to c…

2018

Discovering and Removing Exogenous State Variables and Rewards for Reinforcement Learning

ICML 2018oral

Exogenous state variables and rewards can slow down reinforcement learning by injecting uncontrolled variation into the reward signal. We formalize exogenous state variables and rewards and identify conditions under which an MDP with exogenous state can be decomposed into an exogenous Markov Reward…

Cited by 32SourcePDFScholar
2017

Online Bayesian Transfer Learning for Sequential Data Modeling

ICLR 2017poster

We consider the problem of inferring a sequence of hidden states associated with a sequence of observations produced by an individual within a population. Instead of learning a single sequence model for the population (which does not account for variations within the population), we learn a set of…

Cited by 25SourceScholar
2016

Online Relative Entropy Policy Search using Reproducing Kernel Hilbert Space Embeddings

AISTATS 2016poster

Kernel methods have been successfully applied to reinforcement learning problems to address some challenges such as high dimensional and continuous states, value function approximation and state transition probability modeling. In this paper, we develop an online policy search algorithm based on a r…

Cited by 3SourcePDFScholar