Search Results for author: Yichen Wang

Found 45 papers, 17 papers with code

Deep Probabilistic Modeling of User Behavior for Anomaly Detection via Mixture Density Networks

no code implementations13 May 2025 Lu Dai, Wenxuan Zhu, Xuehui Quan, Renzi Meng, Sheng Chai, Yichen Wang

To improve the identification of potential anomaly patterns in complex user behavior, this paper proposes an anomaly detection method based on a deep mixture density network.

Anomaly Detection

Deep Graph Reinforcement Learning for UAV-Enabled Multi-User Secure Communications

no code implementations2 Apr 2025 Xiao Tang, Kexin Zhao, Chao Shen, Qinghe Du, Yichen Wang, Dusit Niyato, Zhu Han

While unmanned aerial vehicles (UAVs) with flexible mobility are envisioned to enhance physical layer security in wireless communications, the efficient security design that adapts to such high network dynamics is rather challenging.

Graph Neural Network reinforcement-learning +1

Feature Learning beyond the Lazy-Rich Dichotomy: Insights from Representational Geometry

no code implementations23 Mar 2025 Chi-Ning Chou, Hang Le, Yichen Wang, SueYeon Chung

Our framework provides a novel geometric perspective for understanding and quantifying feature learning in both artificial and biological neural networks.

Image Classification Out-of-Distribution Generalization

Test-Time Backdoor Detection for Object Detection Models

no code implementations19 Mar 2025 Hangtao Zhang, Yichen Wang, Shihui Yan, Chenyu Zhu, Ziqi Zhou, Linshan Hou, Shengshan Hu, Minghui Li, Yanjun Zhang, Leo Yu Zhang

To this end, we design TRAnsformation Consistency Evaluation (TRACE), a brand-new method for detecting poisoned samples at test time in object detection.

Image Classification Object +2

Can A Society of Generative Agents Simulate Human Behavior and Inform Public Health Policy? A Case Study on Vaccine Hesitancy

no code implementations12 Mar 2025 Abe Bohan Hou, Hongru Du, Yichen Wang, Jingyu Zhang, Zixiao Wang, Paul Pu Liang, Daniel Khashabi, Lauren Gardner, Tianxing He

Can we simulate a sandbox society with generative agents to model human behavior, thereby reducing the over-reliance on real human trials for assessing public policies?

The Shape of Generalization through the Lens of Norm-based Capacity Control

1 code implementation3 Feb 2025 Yichen Wang, Yudong Chen, Lorenzo Rosasco, Fanghui Liu

Understanding how the test risk scales with model complexity is a central question in machine learning.

Breaking Barriers in Physical-World Adversarial Examples: Improving Robustness and Transferability via Robust Feature

1 code implementation22 Dec 2024 Yichen Wang, Yuxuan Chou, Ziqi Zhou, Hangtao Zhang, Wei Wan, Shengshan Hu, Minghui Li

In the second stage, we use attention-based feature fusion to overlay these RFs onto predictive features of clean images and remove unnecessary perturbations.

Disentanglement

CSP-AIT-Net: A contrastive learning-enhanced spatiotemporal graph attention framework for short-term metro OD flow prediction with asynchronous inflow tracking

no code implementations2 Dec 2024 Yichen Wang, Chengcheng Yu

To address these issues, we propose CSP-AIT-Net, a novel spatiotemporal graph attention framework designed to enhance OD flow prediction by incorporating asynchronous inflow tracking and advanced station semantics representation.

Computational Efficiency Contrastive Learning +3

Jailbreak Large Vision-Language Models Through Multi-Modal Linkage

1 code implementation30 Nov 2024 Yu Wang, Xiaofei Zhou, Yichen Wang, Geyuan Zhang, Tianxing He

With the significant advancement of Large Vision-Language Models (VLMs), concerns about their potential misuse and abuse have grown rapidly.

Perturbation Ontology based Graph Attention Networks

no code implementations27 Nov 2024 Yichen Wang, Jie Wang, Fulin Wang, Xiang Li, Hao Yin, Bhiksha Raj

In recent years, graph representation learning has undergone a paradigm shift, driven by the emergence and proliferation of graph neural networks (GNNs) and their heterogeneous counterparts.

Graph Attention Graph Representation Learning +3

SentiXRL: An advanced large language Model Framework for Multilingual Fine-Grained Emotion Classification in Complex Text Environment

no code implementations27 Nov 2024 Jie Wang, Yichen Wang, Zhilin Zhang, Jianhao Zeng, Kaidi Wang, Zhiyang Chen

With strong expressive capabilities in Large Language Models(LLMs), generative models effectively capture sentiment structures and deep semantics, however, challenges remain in fine-grained sentiment classification across multi-lingual and complex contexts.

Classification Decision Making +8

Multiscale spatiotemporal heterogeneity analysis of bike-sharing system's self-loop phenomenon: Evidence from Shanghai

no code implementations26 Nov 2024 Yichen Wang, Qing Yu, Yancun Song

Marginal treatment effects of residential land use is higher on streets with middle-aged residents, high fixed employment, and low car ownership.

Navigating Spatial Inequities in Freight Truck Crash Severity via Counterfactual Inference in Los Angeles

no code implementations26 Nov 2024 Yichen Wang, Hao Yin, Yifan Yang, Chenyang Zhao, Siqin Wang

Freight truck-related crashes pose significant challenges, leading to substantial economic losses, injuries, and fatalities, with pronounced spatial disparities across different regions.

counterfactual Counterfactual Inference

Concentrate Attention: Towards Domain-Generalizable Prompt Optimization for Language Models

1 code implementation15 Jun 2024 Chengzhengxu Li, Xiaoming Liu, Zhaohan Zhang, Yichen Wang, Chen Liu, Yu Lan, Chao Shen

Recent advances in prompt optimization have notably enhanced the performance of pre-trained language models (PLMs) on downstream tasks.

Domain Generalization

Stumbling Blocks: Stress Testing the Robustness of Machine-Generated Text Detectors Under Attacks

1 code implementation18 Feb 2024 Yichen Wang, Shangbin Feng, Abe Bohan Hou, Xiao Pu, Chao Shen, Xiaoming Liu, Yulia Tsvetkov, Tianxing He

Our experiments reveal that almost none of the existing detectors remain robust under all the attacks, and all detectors exhibit different loopholes.

All

k-SemStamp: A Clustering-Based Semantic Watermark for Detection of Machine-Generated Text

2 code implementations17 Feb 2024 Abe Bohan Hou, Jingyu Zhang, Yichen Wang, Daniel Khashabi, Tianxing He

Recent watermarked generation algorithms inject detectable signatures during language generation to facilitate post-hoc detection.

Text Detection Text Generation

Improving Pacing in Long-Form Story Planning

1 code implementation8 Nov 2023 Yichen Wang, Kevin Yang, Xiaoming Liu, Dan Klein

Existing LLM-based systems for writing long-form stories or story outlines frequently suffer from unnatural pacing, whether glossing over important events or over-elaborating on insignificant details, resulting in a jarring experience for the reader.

Form

Fuzzy-NMS: Improving 3D Object Detection with Fuzzy Classification in NMS

no code implementations21 Oct 2023 Li Wang, Xinyu Zhang, Fachuan Zhao, Chuze Wu, Yichen Wang, Ziying Song, Lei Yang, Jun Li, Huaping Liu

The proposed Fuzzy-NMS module combines the volume and clustering density of candidate bounding boxes, refining them with a fuzzy classification method and optimizing the appropriate suppression thresholds to reduce uncertainty in the NMS process.

3D Object Detection object-detection

Dual Radar: A Multi-modal Dataset with Dual 4D Radar for Autonomous Driving

1 code implementation11 Oct 2023 Xinyu Zhang, Li Wang, Jian Chen, Cheng Fang, Lei Yang, Ziying Song, Guangqi Yang, Yichen Wang, Xiaofei Zhang, Jun Li, Zhiwei Li, Qingshan Yang, Zhenlin Zhang, Shuzhi Sam Ge

Compared with commonly used 3D radars, the latest 4D radars have precise vertical resolution and higher point cloud density, making it a highly promising sensor for autonomous driving in complex environmental perception.

3D Object Detection Autonomous Driving +1

Dialogue for Prompting: a Policy-Gradient-Based Discrete Prompt Generation for Few-shot Learning

1 code implementation14 Aug 2023 Chengzhengxu Li, Xiaoming Liu, Yichen Wang, Duyi Li, Yu Lan, Chao Shen

However, prior discrete prompt optimization methods require expert knowledge to design the base prompt set and identify high-quality prompts, which is costly, inefficient, and subjective.

Few-Shot Learning Reinforcement Learning (RL)

Score Attack: A Lower Bound Technique for Optimal Differentially Private Learning

no code implementations13 Mar 2023 T. Tony Cai, Yichen Wang, Linjun Zhang

The score attack method is based on the tracing attack concept in differential privacy and can be applied to any statistical model with a well-defined score statistic.

parameter estimation

CoCo: Coherence-Enhanced Machine-Generated Text Detection Under Data Limitation With Contrastive Learning

1 code implementation20 Dec 2022 Xiaoming Liu, Zhaohan Zhang, Yichen Wang, Hang Pu, Yu Lan, Chao Shen

Machine-Generated Text (MGT) detection, a task that discriminates MGT from Human-Written Text (HWT), plays a crucial role in preventing misuse of text generative models, which excel in mimicking human writing style recently.

Contrastive Learning Text Detection

The Cost of Privacy in Generalized Linear Models: Algorithms and Minimax Lower Bounds

no code implementations8 Nov 2020 T. Tony Cai, Yichen Wang, Linjun Zhang

We propose differentially private algorithms for parameter estimation in both low-dimensional and high-dimensional sparse generalized linear models (GLMs) by constructing private versions of projected gradient descent.

LEMMA parameter estimation

Learning unbiased zero-shot semantic segmentation networks via transductive transfer

1 code implementation1 Jul 2020 Haiyang Liu, Yichen Wang, Jiayi Zhao, Guowu Yang, Fengmao Lv

Our method assumes that both the source images with full pixel-level labels and unlabeled target images are available during training.

Attribute Prediction +5

Hierarchical Temporal Convolutional Networks for Dynamic Recommender Systems

no code implementations8 Apr 2019 Jiaxuan You, Yichen Wang, Aditya Pal, Pong Eksombatchai, Chuck Rosenberg, Jure Leskovec

Recommender systems that can learn from cross-session data to dynamically predict the next item a user will choose are crucial for online platforms.

Session-Based Recommendations

The Cost of Privacy: Optimal Rates of Convergence for Parameter Estimation with Differential Privacy

no code implementations12 Feb 2019 T. Tony Cai, Yichen Wang, Linjun Zhang

By refining the "tracing adversary" technique for lower bounds in the theoretical computer science literature, we formulate a general lower bound argument for minimax risks with differential privacy constraints, and apply this argument to high-dimensional mean estimation and linear regression problems.

parameter estimation Privacy Preserving +1

Learning to Optimize via Wasserstein Deep Inverse Optimal Control

no code implementations22 May 2018 Yichen Wang, Le Song, Hongyuan Zha

We first propose a unified KL framework that generalizes existing maximum entropy inverse optimal control methods.

Generative Adversarial Network Recommendation Systems +1

Predicting User Activity Level In Point Processes With Mass Transport Equation

no code implementations NeurIPS 2017 Yichen Wang, Xiaojing Ye, Hongyuan Zha, Le Song

Point processes are powerful tools to model user activities and have a plethora of applications in social sciences.

Point Processes

Know-Evolve: Deep Temporal Reasoning for Dynamic Knowledge Graphs

2 code implementations ICML 2017 Rakshit Trivedi, Hanjun Dai, Yichen Wang, Le Song

The occurrence of a fact (edge) is modeled as a multivariate point process whose intensity function is modulated by the score for that fact computed based on the learned entity embeddings.

Entity Embeddings Knowledge Graphs +1

Deep Coevolutionary Network: Embedding User and Item Features for Recommendation

no code implementations13 Sep 2016 Hanjun Dai, Yichen Wang, Rakshit Trivedi, Le Song

DeepCoevolve use recurrent neural network (RNN) over evolving networks to define the intensity function in point processes, which allows the model to capture complex mutual influence between users and items, and the feature evolution over time.

Activity Prediction Network Embedding +2

Fast and Simple Optimization for Poisson Likelihood Models

no code implementations3 Aug 2016 Niao He, Zaid Harchaoui, Yichen Wang, Le Song

Since almost all gradient-based optimization algorithms rely on Lipschitz-continuity, optimizing Poisson likelihood models with a guarantee of convergence can be challenging, especially for large-scale problems.

Time Series Time Series Analysis

Time-Sensitive Recommendation From Recurrent User Activities

no code implementations NeurIPS 2015 Nan Du, Yichen Wang, Niao He, Jimeng Sun, Le Song

By making personalized suggestions, a recommender system is playing a crucial role in improving the engagement of users in modern web-services.

Point Processes Recommendation Systems

COEVOLVE: A Joint Point Process Model for Information Diffusion and Network Co-evolution

1 code implementation NeurIPS 2015 Mehrdad Farajtabar, Yichen Wang, Manuel Gomez Rodriguez, Shuang Li, Hongyuan Zha, Le Song

Information diffusion in online social networks is affected by the underlying network topology, but it also has the power to change it.

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