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Chenghao Liu

34 accepted papers

2026

Hom-PGD+: Fast Reparameterized Optimization over Non-convex Ball-Homeomorphic Set

ICML 2026poster

We study optimization over non-convex constraint sets that are homeomorphic to a ball, encompassing important problem classes such as star-shaped sets that frequently arise in machine learning and engineering applications. We propose Hom-PGD$^+$, a learning-based and projection-efficient first-order…

Cited by 0SourceScholar
2026

It's TIME: Towards the Next Generation of Time Series Forecasting Benchmarks

ICML 2026poster

Time series foundation models (TSFMs) are revolutionizing the forecasting landscape from specific dataset modeling to generalizable task evaluation. However, we contend that existing benchmarks exhibit common limitations in four dimensions: constrained data composition dominated by reused legacy sou…

Cited by 0SourceScholar
2026

MSNAV: ZERO-SHOT VISION-AND-LANGUAGE NAVIGATION WITH DYNAMIC MEMORY AND LLM SPATIAL REASONING

ICASSP 2026poster

Vision-and-Language Navigation (VLN) requires an agent to interpret natural language instructions and navigate complex environments. Current approaches often adopt a "black-box" paradigm, where a single Large Language Model (LLM) makes end-to-end decisions. However, it is plagued by critical vulnera…

Cited by 0SourcePDFScholar
2026

Plan-Answer-Refine-on-Graph: Structured Planning and Self-Refinement for Large Language Model Reasoning on Knowledge Graphs

ICLR 2026poster

Incorporating knowledge graphs (KGs) into large language model (LLM) reasoning has shown promise in alleviating hallucinations and factual errors. Although existing paradigms of KG-augmented LLMs have achieved encouraging results, they still exhibit notable limitations when handling multi-hop reason…

Cited by 0SourceScholar
2026

TTF-VLA: Temporal Token Fusion via Pixel-Attention Integration for Vision-Language-Action Models

AAAI 2026technical

Vision-Language-Action (VLA) models process visual inputs independently at each timestep, discarding valuable temporal information inherent in robotic manipulation tasks. This frame-by-frame processing makes models vulnerable to visual noise while ignoring the substantial coherence between consecuti

Cited by 0SourcePDFScholar
2026

Towards Foundation Models for Zero-Shot Time Series Anomaly Detection: Leveraging Synthetic Data and Relative Context Discrepancy

ICML 2026poster

TSAD is a critical task, but developing models that generalize to unseen data in a zero-shot manner remains a major challenge. Prevailing foundation models for TSAD predominantly rely on reconstruction-based objectives, which suffer from a fundamental objective mismatch and representation conflict: …

Cited by 0SourceScholar
2025

A Picture is Worth A Thousand Numbers: Enabling LLMs Reason about Time Series via Visualization

NAACL 2025long

Large language models (LLMs), with demonstrated reasoning abilities across multiple domains, have been largely underexplored fortime-series reasoning (TsR), which is ubiquitous in the real world. In this work, wepropose TimerBed, the first comprehensivetestbed for evaluating LLMs’ TsR performance.Sp…

2025

David vs. Goliath: Cost-Efficient Financial QA via Cascaded Multi-Agent Reasoning

EMNLP 2025

Large language models (LLMs) have demonstrated remarkable reasoning capabilities, including in financial question answering (FQA). However, the performance in FQA remains limited, particularly in questions that require deep financial knowledge and complex numerical reasoning. While supervised fine-t

2025

Fast Projection-Free Approach (without Optimization Oracle) for Optimization over Compact Convex Set

NeurIPS 2025spotlight

Projection-free first-order methods, e.g., the celebrated Frank-Wolfe (FW) algorithms, have emerged as powerful tools for optimization over simple convex sets such as polyhedra, because of their scalability, fast convergence, and iteration-wise feasibility without costly projections. However, exten…

Cited by 0SourceScholar
2025

Moirai-MoE: Empowering Time Series Foundation Models with Sparse Mixture of Experts

ICML 2025poster

Achieving effective unified pretraining on large time series corpora remains an open challenge in developing time series foundation models. Existing methods, such as Moirai, introduce multiple projection layers for time series of different frequencies to account for high data heterogeneity. We ident…

Cited by 0SourcePDFScholar
2025

Multi-Scale Finetuning for Encoder-based Time Series Foundation Models

NeurIPS 2025poster

Time series foundation models (TSFMs) demonstrate impressive zero-shot performance for time series forecasting. However, an important yet underexplored challenge is how to effectively finetune TSFMs on specific downstream tasks. While naive finetuning can yield performance gains, we argue that it fa…

Cited by 0SourcecodeScholar
2025

ShapeX: Shapelet-Driven Post Hoc Explanations for Time Series Classification Models

NeurIPS 2025poster

Explaining time series classification models is crucial, particularly in high-stakes applications such as healthcare and finance, where transparency and trust play a critical role. Although numerous time series classification methods have identified key subsequences, known as shapelets, as core feat…

Cited by 0SourceScholar
2025

VisionTS: Visual Masked Autoencoders Are Free-Lunch Zero-Shot Time Series Forecasters

ICML 2025poster

Foundation models have emerged as a promising approach in time series forecasting (TSF). Existing approaches either repurpose large language models (LLMs) or build large-scale time series datasets to develop TSF foundation models for universal forecasting. However, these methods face challenges due…

2024

Identifiability Matters: Revealing the Hidden Recoverable Condition in Unbiased Learning to Rank

ICML 2024poster

Unbiased Learning to Rank (ULTR) aims to train unbiased ranking models from biased click logs, by explicitly modeling a generation process for user behavior and fitting click data based on examination hypothesis. Previous research found empirically that the true latent relevance is mostly recoverabl…

2024

PEMT: Multi-Task Correlation Guided Mixture-of-Experts Enables Parameter-Efficient Transfer Learning

ACL 2024findings

Parameter-efficient fine-tuning (PEFT) has emerged as an effective method for adapting pre-trained language models to various tasks efficiently. Recently, there has been a growing interest in transferring knowledge from one or multiple tasks to the downstream target task to achieve performance impro…

Cited by 5SourcePDFScholar
2024

Time-FFM: Towards LM-Empowered Federated Foundation Model for Time Series Forecasting

NeurIPS 2024poster

Unlike natural language processing and computer vision, the development of Foundation Models (FMs) for time series forecasting is blocked due to data scarcity. While recent efforts are focused on building such FMs by unlocking the potential of language models (LMs) for time series analysis, dedicat…

2024

Unified Training of Universal Time Series Forecasting Transformers

ICML 2024oral

Deep learning for time series forecasting has traditionally operated within a one-model-per-dataset framework, limiting its potential to leverage the game-changing impact of large pre-trained models. The concept of *universal forecasting*, emerging from pre-training on a vast collection of time seri…

2023

FedET: A Communication-Efficient Federated Class-Incremental Learning Framework Based on Enhanced Transformer

IJCAI 2023poster

Federated Learning (FL) has been widely concerned for it enables decentralized learning while ensuring data privacy. However, most existing methods unrealistically assume that the classes encountered by local clients are fixed over time. After learning new classes, this impractical assumption will m…

Cited by 30SourcePDFScholar
2023

HyperRouter: Towards Efficient Training and Inference of Sparse Mixture of Experts

EMNLP 2023short main

By routing input tokens to only a few split experts, Sparse Mixture-of-Experts has enabled efficient training of large language models. Recent findings suggest that fixing the routers can achieve competitive performance by alleviating the collapsing problem, where all experts eventually learn simila…

Cited by 0SourcecodeScholar
2023

Learning Deep Time-index Models for Time Series Forecasting

ICML 2023poster

Deep learning has been actively applied to time series forecasting, leading to a deluge of new methods, belonging to the class of historical-value models. Yet, despite the attractive properties of time-index models, such as being able to model the continuous nature of underlying time series dynamics…

2023

Learning Fast and Slow for Online Time Series Forecasting

ICLR 2023poster

Despite the recent success of deep learning for time series forecasting, these methods are not scalable for many real-world applications where data arrives sequentially. Training deep neural forecasters on the fly is notoriously challenging because of their limited ability to adapt to non-stationary…

2022

CoST: Contrastive Learning of Disentangled Seasonal-Trend Representations for Time Series Forecasting

ICLR 2022poster

Deep learning has been actively studied for time series forecasting, and the mainstream paradigm is based on the end-to-end training of neural network architectures, ranging from classical LSTM/RNNs to more recent TCNs and Transformers. Motivated by the recent success of representation learning in c…

2022

Continual Normalization: Rethinking Batch Normalization for Online Continual Learning

ICLR 2022poster

Existing continual learning methods use Batch Normalization (BN) to facilitate training and improve generalization across tasks. However, the non-i.i.d and non-stationary nature of continual learning data, especially in the online setting, amplify the discrepancy between training and testing in BN a…

2022

LBD: Decouple Relevance and Observation for Individual-Level Unbiased Learning to Rank

NeurIPS 2022accept

Using Unbiased Learning to Rank (ULTR) to train the ranking model with biased click logs has attracted increased research interest. The key idea is to explicitly model the user's observation behavior when building the ranker with a large number of click logs. Considering the simplicity, recent effor…

Cited by 5SourcePDFScholar
2021

Contextual Transformation Networks for Online Continual Learning

ICLR 2021poster

Continual learning methods with fixed architectures rely on a single network to learn models that can perform well on all tasks. As a result, they often only accommodate common features of those tasks but neglect each task's specific features. On the other hand, dynamic architecture methods can have…

2021

Relative and Absolute Location Embedding for Few-Shot Node Classification on Graph

AAAI 2021technical

Node classification is an important problem on graphs. While recent advances in graph neural networks achieve promising performance, they require abundant labeled nodes for training. However, in many practical scenarios, there often exist novel classes in which only one or a few labeled nodes are av…

Cited by 101SourcePDFScholar
2020

Adaptive Task Sampling for Meta-Learning

ECCV 2020poster

Meta-learning methods have been extensively studied and applied in computer vision, especially for few-shot classification tasks. The key idea of meta-learning for few-shot classification is to mimic the few-shot situations faced at test time by randomly sampling classes in meta-training data to con…

Cited by 73SourcePDFScholar
2020

MCEN: Bridging Cross-Modal Gap between Cooking Recipes and Dish Images with Latent Variable Model

CVPR 2020poster

Nowadays, driven by the increasing concern on diet and health, food computing has attracted enormous attention from both industry and research community. One of the most popular research topics in this domain is Food Retrieval, due to its profound influence on health-oriented applications. In this p…

Cited by 71PDFScholar
2019

Learning Cross-Modal Embeddings With Adversarial Networks for Cooking Recipes and Food Images

CVPR 2019poster

Food computing is playing an increasingly important role in human daily life, and has found tremendous applications in guiding human behavior towards smart food consumption and healthy lifestyle. An important task under the food-computing umbrella is retrieval, which is particularly helpful for heal…

Cited by 169PDFcodeScholar