3,448 results on '"Liu, Yuchen"'
Search Results
2. Lingma SWE-GPT: An Open Development-Process-Centric Language Model for Automated Software Improvement
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Ma, Yingwei, Cao, Rongyu, Cao, Yongchang, Zhang, Yue, Chen, Jue, Liu, Yibo, Liu, Yuchen, Li, Binhua, Huang, Fei, and Li, Yongbin
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Computer Science - Software Engineering ,Computer Science - Artificial Intelligence - Abstract
Recent advancements in LLM-based agents have led to significant progress in automatic software engineering, particularly in software maintenance and evolution. Despite these encouraging advances, current research faces two major challenges. First, SOTA performance primarily depends on closed-source models, which significantly limits the technology's accessibility, and potential for customization in diverse SE tasks. Second, these models are predominantly trained on static code data, lacking a deep understanding of the dynamic interactions, iterative problem-solving processes, and evolutionary characteristics inherent in software development. To address these challenges, our study adopts a software engineering perspective. We recognize that real-world software maintenance and evolution processes encompass not only static code data but also developers' thought processes, utilization of external tools, and the interaction between different functional personnel. Consequently, we introduce the Lingma SWE-GPT series, comprising Lingma SWE-GPT 7B and 72B. By learning from and simulating real-world code submission activities, Lingma SWE-GPT systematically incorporates the dynamic interactions and iterative problem-solving inherent in software development process, thereby achieving a more comprehensive understanding of software improvement processes. We conducted experimental evaluations using SWE-bench Verified benchmark. The results demonstrate that Lingma SWE-GPT 72B successfully resolves 30.20% of the GitHub issues, marking a significant improvement in automatic issue resolution (22.76% relative improvement compared to Llama 3.1 405B), approaching the performance of closed-source models (31.80\% issues of GPT-4o resolved). Notably, Lingma SWE-GPT 7B resolves 18.20% of the issues, highlighting the potential for applying smaller models to ASE tasks.
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- 2024
3. Unlocking Your Sales Insights: Advanced XGBoost Forecasting Models for Amazon Products
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Wang, Meng, Liu, Yuchen, Li, Gangmin, Payne, Terry R., Yue, Yong, and Man, Ka Lok
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Computer Science - Machine Learning - Abstract
One of the important factors of profitability is the volume of transactions. An accurate prediction of the future transaction volume becomes a pivotal factor in shaping corporate operations and decision-making processes. E-commerce has presented manufacturers with convenient sales channels to, with which the sales can increase dramatically. In this study, we introduce a solution that leverages the XGBoost model to tackle the challenge of predict-ing sales for consumer electronics products on the Amazon platform. Initial-ly, our attempts to solely predict sales volume yielded unsatisfactory results. However, by replacing the sales volume data with sales range values, we achieved satisfactory accuracy with our model. Furthermore, our results in-dicate that XGBoost exhibits superior predictive performance compared to traditional models.
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- 2024
4. Digital Network Twins for Next-generation Wireless: Creation, Optimization, and Challenges
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Liu, Yuchen, Peng, Zhiyuan, Zhang, Zifan, Yu, Hanzhi, and Chen, Mingzhe
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Computer Science - Networking and Internet Architecture - Abstract
Digital network twins (DNTs), by representing a physical network using a virtual model, offer significant benefits such as streamlined network development, enhanced productivity, and cost reduction for next-generation (nextG) communication infrastructure. Existing works mainly describe the deployment of DNT technologies in various service sections.The full life cycle of DNTs for telecommunication has not yet been comprehensively studied, particularly in the aspects of fine-grained creation, real-time adaptation, resource-efficient deployment, and security protection. This article presents an in-depth overview of DNTs, exploring their concrete integration into networks and communication, covering the fundamental designs, the emergent applications, and critical challenges in multiple dimensions. We also include two detailed case studies to illustrate how DNTs can be applied in real-world scenarios such as wireless traffic forecasting and edge caching. Additionally, a forward-looking vision of the research opportunities in tackling the challenges of DNTs is provided, aiming to fully maximize the benefits of DNTs in nextG networks.
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- 2024
5. FlexMol: A Flexible Toolkit for Benchmarking Molecular Relational Learning
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Liu, Sizhe, Xia, Jun, Zhang, Lecheng, Liu, Yuchen, Liu, Yue, Du, Wenjie, Gao, Zhangyang, Hu, Bozhen, Tan, Cheng, Xiang, Hongxin, and Li, Stan Z.
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Computer Science - Machine Learning ,Computer Science - Artificial Intelligence - Abstract
Molecular relational learning (MRL) is crucial for understanding the interaction behaviors between molecular pairs, a critical aspect of drug discovery and development. However, the large feasible model space of MRL poses significant challenges to benchmarking, and existing MRL frameworks face limitations in flexibility and scope. To address these challenges, avoid repetitive coding efforts, and ensure fair comparison of models, we introduce FlexMol, a comprehensive toolkit designed to facilitate the construction and evaluation of diverse model architectures across various datasets and performance metrics. FlexMol offers a robust suite of preset model components, including 16 drug encoders, 13 protein sequence encoders, 9 protein structure encoders, and 7 interaction layers. With its easy-to-use API and flexibility, FlexMol supports the dynamic construction of over 70, 000 distinct combinations of model architectures. Additionally, we provide detailed benchmark results and code examples to demonstrate FlexMol's effectiveness in simplifying and standardizing MRL model development and comparison.
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- 2024
6. Physics-informed Neural Mapping and Motion Planning in Unknown Environments
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Liu, Yuchen, Ni, Ruiqi, and Qureshi, Ahmed H.
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Computer Science - Robotics - Abstract
Mapping and motion planning are two essential elements of robot intelligence that are interdependent in generating environment maps and navigating around obstacles. The existing mapping methods create maps that require computationally expensive motion planning tools to find a path solution. In this paper, we propose a new mapping feature called arrival time fields, which is a solution to the Eikonal equation. The arrival time fields can directly guide the robot in navigating the given environments. Therefore, this paper introduces a new approach called Active Neural Time Fields (Active NTFields), which is a physics-informed neural framework that actively explores the unknown environment and maps its arrival time field on the fly for robot motion planning. Our method does not require any expert data for learning and uses neural networks to directly solve the Eikonal equation for arrival time field mapping and motion planning. We benchmark our approach against state-of-the-art mapping and motion planning methods and demonstrate its superior performance in both simulated and real-world environments with a differential drive robot and a 6 degrees-of-freedom (DOF) robot manipulator. The supplementary videos can be found at https://youtu.be/qTPL5a6pRKk, and the implementation code repository is available at https://github.com/Rtlyc/antfields-demo.
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- 2024
7. Irreducible symplectic varieties with a large second Betti number
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Liu, Yuchen, Liu, Zhiyu, and Xu, Chenyang
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Mathematics - Algebraic Geometry - Abstract
We prove a general result on the existence of irreducible symplectic compactifications of non-compact Lagrangian fibrations. As an application, we show that the relative Jacobian fibration of cubic fivefolds containing a fixed cubic fourfold can be compactified by a $\mathbb{Q}$-factorial terminal irreducible symplectic variety with the second Betti number at least 24, and admits a Lagrangian fibration whose base is a weighted projective space. In particular, it belongs to a new deformation type of irreducible symplectic varieties., Comment: 26 pages. Comments are welcome! ver2: exposition improved, typos corrected
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- 2024
8. Mixture of Efficient Diffusion Experts Through Automatic Interval and Sub-Network Selection
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Ganjdanesh, Alireza, Kang, Yan, Liu, Yuchen, Zhang, Richard, Lin, Zhe, and Huang, Heng
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Diffusion probabilistic models can generate high-quality samples. Yet, their sampling process requires numerous denoising steps, making it slow and computationally intensive. We propose to reduce the sampling cost by pruning a pretrained diffusion model into a mixture of efficient experts. First, we study the similarities between pairs of denoising timesteps, observing a natural clustering, even across different datasets. This suggests that rather than having a single model for all time steps, separate models can serve as ``experts'' for their respective time intervals. As such, we separately fine-tune the pretrained model on each interval, with elastic dimensions in depth and width, to obtain experts specialized in their corresponding denoising interval. To optimize the resource usage between experts, we introduce our Expert Routing Agent, which learns to select a set of proper network configurations. By doing so, our method can allocate the computing budget between the experts in an end-to-end manner without requiring manual heuristics. Finally, with a selected configuration, we fine-tune our pruned experts to obtain our mixture of efficient experts. We demonstrate the effectiveness of our method, DiffPruning, across several datasets, LSUN-Church, LSUN-Beds, FFHQ, and ImageNet, on the Latent Diffusion Model architecture., Comment: Accepted to the 18th European Conference on Computer Vision, ECCV 2024
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- 2024
9. K-semistability of log Fano cone singularities
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Liu, Yuchen and Wu, Yueqiao
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Mathematics - Algebraic Geometry ,Mathematics - Differential Geometry - Abstract
We give a non-Archimedean characterization of K-semistability of log Fano cone singularities, and show that it agrees with the definition originally defined by Collins--Sz\'ekelyhidi. As an application, we show that to test K-semistability, it suffices to test special test configurations. We also show that special test configurations give rise to lc places of torus equivariant bounded complements., Comment: 28 pages
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- 2024
10. Joint Vehicle Connection and Beamforming Optimization in Digital Twin Assisted Integrated Sensing and Communication Vehicular Networks
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Ding, Weihang, Yang, Zhaohui, Chen, Mingzhe, Liu, Yuchen, and Shikh-Bahaei, Mohammad
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Electrical Engineering and Systems Science - Systems and Control - Abstract
This paper introduces an approach to harness digital twin (DT) technology in the realm of integrated sensing and communications (ISAC) in the sixth-generation (6G) Internet-of-everything (IoE) applications. We consider moving targets in a vehicular network and use DT to track and predict the motion of the vehicles. After predicting the location of the vehicle at the next time slot, the DT designs the assignment and beamforming for each vehicle. The real time sensing information is then utilized to update and refine the DT, enabling further processing and decision-making. This model incorporates a dynamic Kalman gain, which is updated at each time slot based on the received echo signals. The state representation encompasses both vehicle motion information and the error matrix, with the posterior Cram\'er-Rao bound (PCRB) employed to assess sensing accuracy. We consider a network with two roadside units (RSUs), and the vehicles need to be allocated to one of them. To optimize the overall transmission rate while maintaining an acceptable sensing accuracy, an optimization problem is formulated. Since it is generally hard to solve the original problem, Lagrange multipliers and fractional programming are employed to simplify this optimization problem. To solve the simplified problem, this paper introduces both greedy and heuristic algorithms through optimizing both vehicle assignments and predictive beamforming. The optimized results are then transferred back to the real space for ISAC applications. Recognizing the computational complexity of the greedy and heuristic algorithms, a bidirectional long short-term memory (LSTM)-based recurrent neural network (RNN) is proposed for efficient beamforming design within the DT. Simulation results demonstrate the effectiveness of the DT-based ISAC network.
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- 2024
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11. Detecting, Explaining, and Mitigating Memorization in Diffusion Models
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Wen, Yuxin, Liu, Yuchen, Chen, Chen, and Lyu, Lingjuan
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Recent breakthroughs in diffusion models have exhibited exceptional image-generation capabilities. However, studies show that some outputs are merely replications of training data. Such replications present potential legal challenges for model owners, especially when the generated content contains proprietary information. In this work, we introduce a straightforward yet effective method for detecting memorized prompts by inspecting the magnitude of text-conditional predictions. Our proposed method seamlessly integrates without disrupting sampling algorithms, and delivers high accuracy even at the first generation step, with a single generation per prompt. Building on our detection strategy, we unveil an explainable approach that shows the contribution of individual words or tokens to memorization. This offers an interactive medium for users to adjust their prompts. Moreover, we propose two strategies i.e., to mitigate memorization by leveraging the magnitude of text-conditional predictions, either through minimization during inference or filtering during training. These proposed strategies effectively counteract memorization while maintaining high-generation quality. Code is available at https://github.com/YuxinWenRick/diffusion_memorization., Comment: 16 pages, 9 figures, accepted as oral presentation in ICLR 2024
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- 2024
12. Engineering Fractional Chern Insulators through Periodic Strain in Monolayer Graphene and Transition Metal Dichalcogenides
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Liu, Yuchen and Zhu, Zheng
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Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We propose the realization of interaction-driven insulators in periodically strained monolayer graphene and transition metal dichalcogenides (TMDs). By analyzing the tunable band structure and band geometry via strain, and performing extensive many-body exact diagonalization of a realistic model, we present compelling evidence for realizing various fractional Chern insulators in both strained monolayer graphene and TMDs. Our thorough analysis across different strain parameters, accounting for experimental variability, reveals that a broad spectrum of fractional Chern insulators, including the Laughlin states, Halperin 112, 332 and 111 states, and Chern number |C| = 2 states, can be stabilized in distinct regions of the phase diagram. These findings suggest that periodically strained monolayer graphene and TMDs provide promising platforms for engineering fractional Chern insulators., Comment: 10 pages, 5+7 figures. We corrected the model of PSTMDs from non-relativistic to massive Dirac electrons in a periodic magnetic field. Fig. 3 has been updated, and exact diagonalization recalculations confirm the FCI
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- 2024
13. Securing Distributed Network Digital Twin Systems Against Model Poisoning Attacks
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Zhang, Zifan, Fang, Minghong, Chen, Mingzhe, Li, Gaolei, Lin, Xi, and Liu, Yuchen
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Computer Science - Networking and Internet Architecture ,Computer Science - Cryptography and Security ,Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
In the era of 5G and beyond, the increasing complexity of wireless networks necessitates innovative frameworks for efficient management and deployment. Digital twins (DTs), embodying real-time monitoring, predictive configurations, and enhanced decision-making capabilities, stand out as a promising solution in this context. Within a time-series data-driven framework that effectively maps wireless networks into digital counterparts, encapsulated by integrated vertical and horizontal twinning phases, this study investigates the security challenges in distributed network DT systems, which potentially undermine the reliability of subsequent network applications such as wireless traffic forecasting. Specifically, we consider a minimal-knowledge scenario for all attackers, in that they do not have access to network data and other specialized knowledge, yet can interact with previous iterations of server-level models. In this context, we spotlight a novel fake traffic injection attack designed to compromise a distributed network DT system for wireless traffic prediction. In response, we then propose a defense mechanism, termed global-local inconsistency detection (GLID), to counteract various model poisoning threats. GLID strategically removes abnormal model parameters that deviate beyond a particular percentile range, thereby fortifying the security of network twinning process. Through extensive experiments on real-world wireless traffic datasets, our experimental evaluations show that both our attack and defense strategies significantly outperform existing baselines, highlighting the importance of security measures in the design and implementation of DTs for 5G and beyond network systems., Comment: Accepted by Internet of Things Journal (IoT-J). arXiv admin note: substantial text overlap with arXiv:2404.14389
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- 2024
14. Good moduli spaces for boundary polarized Calabi-Yau surface pairs
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Blum, Harold and Liu, Yuchen
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Mathematics - Algebraic Geometry ,Mathematics - Differential Geometry - Abstract
We construct projective asymptotically good moduli spaces parametrizing boundary polarized CY surface pairs, which are projective slc Calabi-Yau pairs $(X,D)$ such that $D$ is ample and $X$ has dimension two. The moduli space provides a wall crossing between certain KSBA and K-moduli spaces and is the ample model of the Hodge line bundle. In the case of K3 surfaces with a non-symplectic automorphism, the moduli space gives a modular interpretation for the Baily--Borel compactification., Comment: 57 pages, comments are very welcome
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- 2024
15. Digital Twin-Assisted Data-Driven Optimization for Reliable Edge Caching in Wireless Networks
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Zhang, Zifan, Liu, Yuchen, Peng, Zhiyuan, Chen, Mingzhe, Xu, Dongkuan, and Cui, Shuguang
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Computer Science - Networking and Internet Architecture ,Computer Science - Machine Learning - Abstract
Optimizing edge caching is crucial for the advancement of next-generation (nextG) wireless networks, ensuring high-speed and low-latency services for mobile users. Existing data-driven optimization approaches often lack awareness of the distribution of random data variables and focus solely on optimizing cache hit rates, neglecting potential reliability concerns, such as base station overload and unbalanced cache issues. This oversight can result in system crashes and degraded user experience. To bridge this gap, we introduce a novel digital twin-assisted optimization framework, called D-REC, which integrates reinforcement learning (RL) with diverse intervention modules to ensure reliable caching in nextG wireless networks. We first develop a joint vertical and horizontal twinning approach to efficiently create network digital twins, which are then employed by D-REC as RL optimizers and safeguards, providing ample datasets for training and predictive evaluation of our cache replacement policy. By incorporating reliability modules into a constrained Markov decision process, D-REC can adaptively adjust actions, rewards, and states to comply with advantageous constraints, minimizing the risk of network failures. Theoretical analysis demonstrates comparable convergence rates between D-REC and vanilla data-driven methods without compromising caching performance. Extensive experiments validate that D-REC outperforms conventional approaches in cache hit rate and load balancing while effectively enforcing predetermined reliability intervention modules., Comment: Accepted by IEEE Journal on Selected Areas in Communications (JSAC)
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- 2024
16. Byzantine-Robust Decentralized Federated Learning
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Fang, Minghong, Zhang, Zifan, Hairi, Khanduri, Prashant, Liu, Jia, Lu, Songtao, Liu, Yuchen, and Gong, Neil
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Computer Science - Cryptography and Security ,Computer Science - Distributed, Parallel, and Cluster Computing ,Computer Science - Machine Learning - Abstract
Federated learning (FL) enables multiple clients to collaboratively train machine learning models without revealing their private training data. In conventional FL, the system follows the server-assisted architecture (server-assisted FL), where the training process is coordinated by a central server. However, the server-assisted FL framework suffers from poor scalability due to a communication bottleneck at the server, and trust dependency issues. To address challenges, decentralized federated learning (DFL) architecture has been proposed to allow clients to train models collaboratively in a serverless and peer-to-peer manner. However, due to its fully decentralized nature, DFL is highly vulnerable to poisoning attacks, where malicious clients could manipulate the system by sending carefully-crafted local models to their neighboring clients. To date, only a limited number of Byzantine-robust DFL methods have been proposed, most of which are either communication-inefficient or remain vulnerable to advanced poisoning attacks. In this paper, we propose a new algorithm called BALANCE (Byzantine-robust averaging through local similarity in decentralization) to defend against poisoning attacks in DFL. In BALANCE, each client leverages its own local model as a similarity reference to determine if the received model is malicious or benign. We establish the theoretical convergence guarantee for BALANCE under poisoning attacks in both strongly convex and non-convex settings. Furthermore, the convergence rate of BALANCE under poisoning attacks matches those of the state-of-the-art counterparts in Byzantine-free settings. Extensive experiments also demonstrate that BALANCE outperforms existing DFL methods and effectively defends against poisoning attacks., Comment: To appear in ACM Conference on Computer and Communications Security 2024 (CCS '24)
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- 2024
17. Wall-crossing for K-moduli spaces of certain families of weighted projective hypersurfaces
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Kim, In-Kyun, Liu, Yuchen, and Wang, Chengxi
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Mathematics - Algebraic Geometry - Abstract
We describe the K-moduli spaces of weighted hypersurfaces of degree $2(n+3)$ in $\mathbb{P}(1,2,n+2,n+3)$. We show that the K-polystable limits of these weighted hypersurfaces are also weighted hypersurfaces of the same degree in the same weighted projective space. This is achieved by an explicit study of the wall crossing for K-moduli spaces $M_w$ of certain log Fano pairs with coefficient $w$ whose double cover gives the weighted hypersurface. Moreover, we show that the wall crossing of $M_w$ coincides with variation of GIT except at the last K-moduli wall which gives a divisorial contraction. Our K-moduli spaces provide new birational models for some natural loci in the moduli space of marked hyperelliptic curves., Comment: 52 pages
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- 2024
18. Seed-TTS: A Family of High-Quality Versatile Speech Generation Models
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Anastassiou, Philip, Chen, Jiawei, Chen, Jitong, Chen, Yuanzhe, Chen, Zhuo, Chen, Ziyi, Cong, Jian, Deng, Lelai, Ding, Chuang, Gao, Lu, Gong, Mingqing, Huang, Peisong, Huang, Qingqing, Huang, Zhiying, Huo, Yuanyuan, Jia, Dongya, Li, Chumin, Li, Feiya, Li, Hui, Li, Jiaxin, Li, Xiaoyang, Li, Xingxing, Liu, Lin, Liu, Shouda, Liu, Sichao, Liu, Xudong, Liu, Yuchen, Liu, Zhengxi, Lu, Lu, Pan, Junjie, Wang, Xin, Wang, Yuping, Wang, Yuxuan, Wei, Zhen, Wu, Jian, Yao, Chao, Yang, Yifeng, Yi, Yuanhao, Zhang, Junteng, Zhang, Qidi, Zhang, Shuo, Zhang, Wenjie, Zhang, Yang, Zhao, Zilin, Zhong, Dejian, and Zhuang, Xiaobin
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Electrical Engineering and Systems Science - Audio and Speech Processing ,Computer Science - Sound - Abstract
We introduce Seed-TTS, a family of large-scale autoregressive text-to-speech (TTS) models capable of generating speech that is virtually indistinguishable from human speech. Seed-TTS serves as a foundation model for speech generation and excels in speech in-context learning, achieving performance in speaker similarity and naturalness that matches ground truth human speech in both objective and subjective evaluations. With fine-tuning, we achieve even higher subjective scores across these metrics. Seed-TTS offers superior controllability over various speech attributes such as emotion and is capable of generating highly expressive and diverse speech for speakers in the wild. Furthermore, we propose a self-distillation method for speech factorization, as well as a reinforcement learning approach to enhance model robustness, speaker similarity, and controllability. We additionally present a non-autoregressive (NAR) variant of the Seed-TTS model, named $\text{Seed-TTS}_\text{DiT}$, which utilizes a fully diffusion-based architecture. Unlike previous NAR-based TTS systems, $\text{Seed-TTS}_\text{DiT}$ does not depend on pre-estimated phoneme durations and performs speech generation through end-to-end processing. We demonstrate that this variant achieves comparable performance to the language model-based variant and showcase its effectiveness in speech editing. We encourage readers to listen to demos at \url{https://bytedancespeech.github.io/seedtts_tech_report}.
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- 2024
19. Self-Modifying State Modeling for Simultaneous Machine Translation
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Yu, Donglei, Kang, Xiaomian, Liu, Yuchen, Zhou, Yu, and Zong, Chengqing
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Computer Science - Computation and Language - Abstract
Simultaneous Machine Translation (SiMT) generates target outputs while receiving stream source inputs and requires a read/write policy to decide whether to wait for the next source token or generate a new target token, whose decisions form a \textit{decision path}. Existing SiMT methods, which learn the policy by exploring various decision paths in training, face inherent limitations. These methods not only fail to precisely optimize the policy due to the inability to accurately assess the individual impact of each decision on SiMT performance, but also cannot sufficiently explore all potential paths because of their vast number. Besides, building decision paths requires unidirectional encoders to simulate streaming source inputs, which impairs the translation quality of SiMT models. To solve these issues, we propose \textbf{S}elf-\textbf{M}odifying \textbf{S}tate \textbf{M}odeling (SM$^2$), a novel training paradigm for SiMT task. Without building decision paths, SM$^2$ individually optimizes decisions at each state during training. To precisely optimize the policy, SM$^2$ introduces Self-Modifying process to independently assess and adjust decisions at each state. For sufficient exploration, SM$^2$ proposes Prefix Sampling to efficiently traverse all potential states. Moreover, SM$^2$ ensures compatibility with bidirectional encoders, thus achieving higher translation quality. Experiments show that SM$^2$ outperforms strong baselines. Furthermore, SM$^2$ allows offline machine translation models to acquire SiMT ability with fine-tuning., Comment: Accept to ACL 2024 main conference. 15 pages, 13 figures, 9 tables
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- 2024
20. A note on Koll\'{a}r valuations
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Liu, Yuchen and Xu, Chenyang
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Mathematics - Algebraic Geometry ,Mathematics - Commutative Algebra - Abstract
We prove the set of Koll\'{a}r valuations in the dual complex of a klt singularity with a fixed complement is path connected. We also classify the case when the dual complex is one dimensional., Comment: 9 pages, comments welcome. To appear in SCIENCE CHINA Mathematics, special issue in memory of Professor Gang Xiao
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- 2024
21. SNED: Superposition Network Architecture Search for Efficient Video Diffusion Model
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Li, Zhengang, Kang, Yan, Liu, Yuchen, Liu, Difan, Hinz, Tobias, Liu, Feng, and Wang, Yanzhi
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Artificial Intelligence - Abstract
While AI-generated content has garnered significant attention, achieving photo-realistic video synthesis remains a formidable challenge. Despite the promising advances in diffusion models for video generation quality, the complex model architecture and substantial computational demands for both training and inference create a significant gap between these models and real-world applications. This paper presents SNED, a superposition network architecture search method for efficient video diffusion model. Our method employs a supernet training paradigm that targets various model cost and resolution options using a weight-sharing method. Moreover, we propose the supernet training sampling warm-up for fast training optimization. To showcase the flexibility of our method, we conduct experiments involving both pixel-space and latent-space video diffusion models. The results demonstrate that our framework consistently produces comparable results across different model options with high efficiency. According to the experiment for the pixel-space video diffusion model, we can achieve consistent video generation results simultaneously across 64 x 64 to 256 x 256 resolutions with a large range of model sizes from 640M to 1.6B number of parameters for pixel-space video diffusion models., Comment: Accepted in CVPR 2024
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- 2024
22. Online Analytic Exemplar-Free Continual Learning with Large Models for Imbalanced Autonomous Driving Task
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Zhuang, Huiping, Fang, Di, Tong, Kai, Liu, Yuchen, Zeng, Ziqian, Zhou, Xu, and Chen, Cen
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Computer Science - Machine Learning ,Computer Science - Robotics ,I.2.6 - Abstract
In autonomous driving, even a meticulously trained model can encounter failures when facing unfamiliar scenarios. One of these scenarios can be formulated as an online continual learning (OCL) problem. That is, data come in an online fashion, and models are updated according to these streaming data. Two major OCL challenges are catastrophic forgetting and data imbalance. To address these challenges, in this paper, we propose an Analytic Exemplar-Free Online Continual Learning algorithm (AEF-OCL). The AEF-OCL leverages analytic continual learning principles and employs ridge regression as a classifier for features extracted by a large backbone network. It solves the OCL problem by recursively calculating the analytical solution, ensuring an equalization between the continual learning and its joint-learning counterpart, and works without the need to save any used samples (i.e., exemplar-free). Additionally, we introduce a Pseudo-Features Generator (PFG) module that recursively estimates the mean and the variance of real features for each class. It over-samples offset pseudo-features from the same normal distribution as the real features, thereby addressing the data imbalance issue. Experimental results demonstrate that despite being an exemplar-free strategy, our method outperforms various methods on the autonomous driving SODA10M dataset. Source code is available at https://github.com/ZHUANGHP/Analytic-continual-learning., Comment: This paper is to be published in IEEE Transactions on Vehicular Technology
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- 2024
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23. Visualizing the Shadows: Unveiling Data Poisoning Behaviors in Federated Learning
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Zhang, Xueqing, Zhang, Junkai, Chow, Ka-Ho, Chen, Juntao, Mao, Ying, Rahouti, Mohamed, Li, Xiang, Liu, Yuchen, and Wei, Wenqi
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Computer Science - Cryptography and Security - Abstract
This demo paper examines the susceptibility of Federated Learning (FL) systems to targeted data poisoning attacks, presenting a novel system for visualizing and mitigating such threats. We simulate targeted data poisoning attacks via label flipping and analyze the impact on model performance, employing a five-component system that includes Simulation and Data Generation, Data Collection and Upload, User-friendly Interface, Analysis and Insight, and Advisory System. Observations from three demo modules: label manipulation, attack timing, and malicious attack availability, and two analysis components: utility and analytical behavior of local model updates highlight the risks to system integrity and offer insight into the resilience of FL systems. The demo is available at https://github.com/CathyXueqingZhang/DataPoisoningVis.
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- 2024
24. Personalized Residuals for Concept-Driven Text-to-Image Generation
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Ham, Cusuh, Fisher, Matthew, Hays, James, Kolkin, Nicholas, Liu, Yuchen, Zhang, Richard, and Hinz, Tobias
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Computer Science - Computer Vision and Pattern Recognition - Abstract
We present personalized residuals and localized attention-guided sampling for efficient concept-driven generation using text-to-image diffusion models. Our method first represents concepts by freezing the weights of a pretrained text-conditioned diffusion model and learning low-rank residuals for a small subset of the model's layers. The residual-based approach then directly enables application of our proposed sampling technique, which applies the learned residuals only in areas where the concept is localized via cross-attention and applies the original diffusion weights in all other regions. Localized sampling therefore combines the learned identity of the concept with the existing generative prior of the underlying diffusion model. We show that personalized residuals effectively capture the identity of a concept in ~3 minutes on a single GPU without the use of regularization images and with fewer parameters than previous models, and localized sampling allows using the original model as strong prior for large parts of the image., Comment: CVPR 2024. Project page at https://cusuh.github.io/personalized-residuals
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- 2024
25. K-stability of special Gushel-Mukai manifolds
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Liu, Yuchen and Wang, Linsheng
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Mathematics - Algebraic Geometry ,Mathematics - Differential Geometry ,14J45, 32Q20, 14D20 - Abstract
Gushel-Mukai manifolds are specific families of $n$-dimensional Fano manifolds of Picard rank $1$ and index $n-2$ where $3\leq n \leq 6$. A Gushel-Mukai $n$-fold is either ordinary, i.e. a hyperquadric section of a quintic Del Pezzo $(n+1)$-fold, or special, i.e. it admits a double cover over the quintic Del Pezzo $n$-fold branched along an ordinary Gushel-Mukai $(n-1)$-fold. In this paper, we prove that a general special Gushel-Mukai $n$-fold is K-stable for every $3\leq n\leq 6$. Furthermore, we give a description of the first and last walls of the K-moduli of the pair $(M,cQ)$, where $M$ is the quintic Del Pezzo fourfold (or fivefold) and $Q$ is an ordinary Gushel-Mukai threefold (or fourfold). Besides, we compute $\delta$-invariants of quintic Del Pezzo fourfolds and fivefolds which were shown to be K-unstable by K. Fujita, and show that they admit K\"ahler-Ricci solitons., Comment: 31 pages, comments are very welcome
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- 2024
26. Attention-Driven Training-Free Efficiency Enhancement of Diffusion Models
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Wang, Hongjie, Liu, Difan, Kang, Yan, Li, Yijun, Lin, Zhe, Jha, Niraj K., and Liu, Yuchen
- Subjects
Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Artificial Intelligence ,Computer Science - Machine Learning ,Electrical Engineering and Systems Science - Image and Video Processing ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Diffusion Models (DMs) have exhibited superior performance in generating high-quality and diverse images. However, this exceptional performance comes at the cost of expensive architectural design, particularly due to the attention module heavily used in leading models. Existing works mainly adopt a retraining process to enhance DM efficiency. This is computationally expensive and not very scalable. To this end, we introduce the Attention-driven Training-free Efficient Diffusion Model (AT-EDM) framework that leverages attention maps to perform run-time pruning of redundant tokens, without the need for any retraining. Specifically, for single-denoising-step pruning, we develop a novel ranking algorithm, Generalized Weighted Page Rank (G-WPR), to identify redundant tokens, and a similarity-based recovery method to restore tokens for the convolution operation. In addition, we propose a Denoising-Steps-Aware Pruning (DSAP) approach to adjust the pruning budget across different denoising timesteps for better generation quality. Extensive evaluations show that AT-EDM performs favorably against prior art in terms of efficiency (e.g., 38.8% FLOPs saving and up to 1.53x speed-up over Stable Diffusion XL) while maintaining nearly the same FID and CLIP scores as the full model. Project webpage: https://atedm.github.io., Comment: Accepted to IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) 2024
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- 2024
27. Mapping Wireless Networks into Digital Reality through Joint Vertical and Horizontal Learning
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Zhang, Zifan, Chen, Mingzhe, Yang, Zhaohui, and Liu, Yuchen
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Computer Science - Networking and Internet Architecture ,Computer Science - Machine Learning ,Electrical Engineering and Systems Science - Signal Processing ,C.2.1 - Abstract
In recent years, the complexity of 5G and beyond wireless networks has escalated, prompting a need for innovative frameworks to facilitate flexible management and efficient deployment. The concept of digital twins (DTs) has emerged as a solution to enable real-time monitoring, predictive configurations, and decision-making processes. While existing works primarily focus on leveraging DTs to optimize wireless networks, a detailed mapping methodology for creating virtual representations of network infrastructure and properties is still lacking. In this context, we introduce VH-Twin, a novel time-series data-driven framework that effectively maps wireless networks into digital reality. VH-Twin distinguishes itself through complementary vertical twinning (V-twinning) and horizontal twinning (H-twinning) stages, followed by a periodic clustering mechanism used to virtualize network regions based on their distinct geological and wireless characteristics. Specifically, V-twinning exploits distributed learning techniques to initialize a global twin model collaboratively from virtualized network clusters. H-twinning, on the other hand, is implemented with an asynchronous mapping scheme that dynamically updates twin models in response to network or environmental changes. Leveraging real-world wireless traffic data within a cellular wireless network, comprehensive experiments are conducted to verify that VH-Twin can effectively construct, deploy, and maintain network DTs. Parametric analysis also offers insights into how to strike a balance between twinning efficiency and model accuracy at scale., Comment: Accepted by IFIP/IEEE Networking 2024
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- 2024
28. Poisoning Attacks on Federated Learning-based Wireless Traffic Prediction
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Zhang, Zifan, Fang, Minghong, Huang, Jiayuan, and Liu, Yuchen
- Subjects
Computer Science - Networking and Internet Architecture ,Computer Science - Cryptography and Security ,Computer Science - Machine Learning ,C.2.1 - Abstract
Federated Learning (FL) offers a distributed framework to train a global control model across multiple base stations without compromising the privacy of their local network data. This makes it ideal for applications like wireless traffic prediction (WTP), which plays a crucial role in optimizing network resources, enabling proactive traffic flow management, and enhancing the reliability of downstream communication-aided applications, such as IoT devices, autonomous vehicles, and industrial automation systems. Despite its promise, the security aspects of FL-based distributed wireless systems, particularly in regression-based WTP problems, remain inadequately investigated. In this paper, we introduce a novel fake traffic injection (FTI) attack, designed to undermine the FL-based WTP system by injecting fabricated traffic distributions with minimal knowledge. We further propose a defense mechanism, termed global-local inconsistency detection (GLID), which strategically removes abnormal model parameters that deviate beyond a specific percentile range estimated through statistical methods in each dimension. Extensive experimental evaluations, performed on real-world wireless traffic datasets, demonstrate that both our attack and defense strategies significantly outperform existing baselines., Comment: Accepted by IFIP/IEEE Networking 2024
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- 2024
29. Towards Human Awareness in Robot Task Planning with Large Language Models
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Liu, Yuchen, Palmieri, Luigi, Koch, Sebastian, Georgievski, Ilche, and Aiello, Marco
- Subjects
Computer Science - Robotics - Abstract
The recent breakthroughs in the research on Large Language Models (LLMs) have triggered a transformation across several research domains. Notably, the integration of LLMs has greatly enhanced performance in robot Task And Motion Planning (TAMP). However, previous approaches often neglect the consideration of dynamic environments, i.e., the presence of dynamic objects such as humans. In this paper, we propose a novel approach to address this gap by incorporating human awareness into LLM-based robot task planning. To obtain an effective representation of the dynamic environment, our approach integrates humans' information into a hierarchical scene graph. To ensure the plan's executability, we leverage LLMs to ground the environmental topology and actionable knowledge into formal planning language. Most importantly, we use LLMs to predict future human activities and plan tasks for the robot considering the predictions. Our contribution facilitates the development of integrating human awareness into LLM-driven robot task planning, and paves the way for proactive robot decision-making in dynamic environments.
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- 2024
30. F-MALLOC: Feed-forward Memory Allocation for Continual Learning in Neural Machine Translation
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Wu, Junhong, Liu, Yuchen, and Zong, Chengqing
- Subjects
Computer Science - Computation and Language - Abstract
In the evolving landscape of Neural Machine Translation (NMT), the pretrain-then-finetune paradigm has yielded impressive results. However, the persistent challenge of Catastrophic Forgetting (CF) remains a hurdle. While previous work has introduced Continual Learning (CL) methods to address CF, these approaches grapple with the delicate balance between avoiding forgetting and maintaining system extensibility. To address this, we propose a CL method, named $\textbf{F-MALLOC}$ ($\textbf{F}$eed-forward $\textbf{M}$emory $\textbf{ALLOC}ation)$. F-MALLOC is inspired by recent insights highlighting that feed-forward layers emulate neural memories and encapsulate crucial translation knowledge. It decomposes feed-forward layers into discrete memory cells and allocates these memories to different tasks. By learning to allocate and safeguard these memories, our method effectively alleviates CF while ensuring robust extendability. Besides, we propose a comprehensive assessment protocol for multi-stage CL of NMT systems. Experiments conducted following this new protocol showcase the superior performance of F-MALLOC, evidenced by higher BLEU scores and almost zero forgetting., Comment: Accepted to the main conference of NAACL 2024
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- 2024
31. DELTA: Decomposed Efficient Long-Term Robot Task Planning using Large Language Models
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Liu, Yuchen, Palmieri, Luigi, Koch, Sebastian, Georgievski, Ilche, and Aiello, Marco
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Computer Science - Robotics ,Computer Science - Artificial Intelligence - Abstract
Recent advancements in Large Language Models (LLMs) have sparked a revolution across many research fields. In robotics, the integration of common-sense knowledge from LLMs into task and motion planning has drastically advanced the field by unlocking unprecedented levels of context awareness. Despite their vast collection of knowledge, large language models may generate infeasible plans due to hallucinations or missing domain information. To address these challenges and improve plan feasibility and computational efficiency, we introduce DELTA, a novel LLM-informed task planning approach. By using scene graphs as environment representations within LLMs, DELTA achieves rapid generation of precise planning problem descriptions. To enhance planning performance, DELTA decomposes long-term task goals with LLMs into an autoregressive sequence of sub-goals, enabling automated task planners to efficiently solve complex problems. In our extensive evaluation, we show that DELTA enables an efficient and fully automatic task planning pipeline, achieving higher planning success rates and significantly shorter planning times compared to the state of the art.
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- 2024
32. Spikewhisper: Temporal Spike Backdoor Attacks on Federated Neuromorphic Learning over Low-power Devices
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Fu, Hanqing, Li, Gaolei, Wu, Jun, Li, Jianhua, Lin, Xi, Zhou, Kai, and Liu, Yuchen
- Subjects
Computer Science - Cryptography and Security ,Computer Science - Artificial Intelligence ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Federated neuromorphic learning (FedNL) leverages event-driven spiking neural networks and federated learning frameworks to effectively execute intelligent analysis tasks over amounts of distributed low-power devices but also perform vulnerability to poisoning attacks. The threat of backdoor attacks on traditional deep neural networks typically comes from time-invariant data. However, in FedNL, unknown threats may be hidden in time-varying spike signals. In this paper, we start to explore a novel vulnerability of FedNL-based systems with the concept of time division multiplexing, termed Spikewhisper, which allows attackers to evade detection as much as possible, as multiple malicious clients can imperceptibly poison with different triggers at different timeslices. In particular, the stealthiness of Spikewhisper is derived from the time-domain divisibility of global triggers, in which each malicious client pastes only one local trigger to a certain timeslice in the neuromorphic sample, and also the polarity and motion of each local trigger can be configured by attackers. Extensive experiments based on two different neuromorphic datasets demonstrate that the attack success rate of Spikewispher is higher than the temporally centralized attacks. Besides, it is validated that the effect of Spikewispher is sensitive to the trigger duration.
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- 2024
33. K-moduli of Fano threefolds and genus four curves
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Liu, Yuchen and Zhao, Junyan
- Subjects
Mathematics - Algebraic Geometry - Abstract
In this article, we study the K-moduli space of Fano threefolds obtained by blowing up $\mathbb{P}^3$ along $(2,3)$-complete intersection curves. This K-moduli space is a two-step birational modification of the GIT moduli space of $(3,3)$-curves on $\mathbb{P}^1 \times \mathbb{P}^1$. As an application, we show that our K-moduli space appears as one model of the Hassett--Keel program for $\overline{M}_4$. In particular, we classify all K-(semi/poly)stable members in this deformation family of Fano varieties. We follow the moduli continuity method with moduli of lattice-polarized K3 surfaces, general elephants and Sarkisov links as new ingredients., Comment: 36 pages, comments are welcome
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- 2024
34. F-OAL: Forward-only Online Analytic Learning with Fast Training and Low Memory Footprint in Class Incremental Learning
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Zhuang, Huiping, Liu, Yuchen, He, Run, Tong, Kai, Zeng, Ziqian, Chen, Cen, Wang, Yi, and Chau, Lap-Pui
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
Online Class Incremental Learning (OCIL) aims to train models incrementally, where data arrive in mini-batches, and previous data are not accessible. A major challenge in OCIL is Catastrophic Forgetting, i.e., the loss of previously learned knowledge. Among existing baselines, replay-based methods show competitive results but requires extra memory for storing exemplars, while exemplar-free (i.e., data need not be stored for replay in production) methods are resource-friendly but often lack accuracy. In this paper, we propose an exemplar-free approach--Forward-only Online Analytic Learning (F-OAL). Unlike traditional methods, F-OAL does not rely on back-propagation and is forward-only, significantly reducing memory usage and computational time. Cooperating with a pre-trained frozen encoder with Feature Fusion, F-OAL only needs to update a linear classifier by recursive least square. This approach simultaneously achieves high accuracy and low resource consumption. Extensive experiments on benchmark datasets demonstrate F-OAL's robust performance in OCIL scenarios. Code is available at https://github.com/liuyuchen-cz/F-OAL.
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- 2024
35. Complex-Valued Neural Network based Federated Learning for Multi-user Indoor Positioning Performance Optimization
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Yu, Hanzhi, Liu, Yuchen, and Chen, Mingzhe
- Subjects
Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
In this article, the use of channel state information (CSI) for indoor positioning is studied. In the considered model, a server equipped with several antennas sends pilot signals to users, while each user uses the received pilot signals to estimate channel states for user positioning. To this end, we formulate the positioning problem as an optimization problem aiming to minimize the gap between the estimated positions and the ground truth positions of users. To solve this problem, we design a complex-valued neural network (CVNN) model based federated learning (FL) algorithm. Compared to standard real-valued centralized machine learning (ML) methods, our proposed algorithm has two main advantages. First, our proposed algorithm can directly process complex-valued CSI data without data transformation. Second, our proposed algorithm is a distributed ML method that does not require users to send their CSI data to the server. Since the output of our proposed algorithm is complex-valued which consists of the real and imaginary parts, we study the use of the CVNN to implement two learning tasks. First, the proposed algorithm directly outputs the estimated positions of a user. Here, the real and imaginary parts of an output neuron represent the 2D coordinates of the user. Second, the proposed method can output two CSI features (i.e., line-of-sight/non-line-of-sight transmission link classification and time of arrival (TOA) prediction) which can be used in traditional positioning algorithms. Simulation results demonstrate that our designed CVNN based FL can reduce the mean positioning error between the estimated position and the actual position by up to 36%, compared to a RVNN based FL which requires to transform CSI data into real-valued data., Comment: 13 pages, 10 figures
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- 2024
36. Dysfunction in sensorimotor and default mode networks in major depressive disorder with insights from global brain connectivity
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Zhang, Yajuan, Huang, Chu-Chung, Zhao, Jiajia, Liu, Yuchen, Xia, Mingrui, Wang, Xiaoqin, Wei, Dongtao, Chen, Yuan, Liu, Bangshan, Zheng, Yanting, Wu, Yankun, Chen, Taolin, Cheng, Yuqi, Xu, Xiufeng, Gong, Qiyong, Si, Tianmei, Qiu, Shijun, Cheng, Jingliang, Tang, Yanqing, Wang, Fei, Qiu, Jiang, Xie, Peng, Li, Lingjiang, He, Yong, Lin, Ching-Po, and Lo, Chun-Yi Zac
- Published
- 2024
- Full Text
- View/download PDF
37. Gray matter and cognitive alteration related to chronic obstructive pulmonary disease patients: combining ALE meta-analysis and MACM analysis
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Liang, Junquan, Yu, Qiaoyun, Chen, Limei, Li, Zhongxian, Liu, Yuchen, Qiu, Yidan, Guan, Huiting, Tang, Rundong, Yan, Luda, and Zhou, Peng
- Published
- 2024
- Full Text
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38. Edge effect during microwave plasma chemical vapor deposition diamond-film: Multiphysics simulation and experimental verification
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Yang, Zhiliang, An, Kang, Liu, Yuchen, Guo, Zhijian, Shao, Siwu, Liu, Jinlong, Wei, Junjun, Chen, Liangxian, Wu, Lishu, and Li, Chengming
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- 2024
- Full Text
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39. The Role of the COVID-19 Pandemic and Marginalized Identities in US Medical Students’ Burnout, Career Regret, and Medical School Experiences
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Liu, Yuchen and Frazier, Patricia A.
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- 2024
- Full Text
- View/download PDF
40. ToolNet: Connecting Large Language Models with Massive Tools via Tool Graph
- Author
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Liu, Xukun, Peng, Zhiyuan, Yi, Xiaoyuan, Xie, Xing, Xiang, Lirong, Liu, Yuchen, and Xu, Dongkuan
- Subjects
Computer Science - Artificial Intelligence ,Computer Science - Computation and Language - Abstract
While achieving remarkable progress in a broad range of tasks, large language models (LLMs) remain significantly limited in properly using massive external tools. Existing in-context learning approaches simply format tools into a list of plain text descriptions and input them to LLMs, from which, LLMs generate a sequence of tool calls to solve problems step by step. Such a paradigm ignores the intrinsic dependency between tools and offloads all reasoning loads to LLMs, making them restricted to a limited number of specifically designed tools. It thus remains challenging for LLMs to operate on a library of massive tools, casting a great limitation when confronted with real-world scenarios. This paper proposes ToolNet, a plug-and-play framework that scales up the number of tools to thousands with a moderate increase in token consumption. ToolNet organizes tools into a directed graph. Each node represents a tool, and weighted edges denote tool transition. Starting from an initial tool node, an LLM navigates in the graph by iteratively choosing the next one from its successors until the task is resolved. Extensive experiments show that ToolNet can achieve impressive results in challenging multi-hop tool learning datasets and is resilient to tool failures.
- Published
- 2024
41. Attosecond X-ray Chronoscopy of Core-level Photoemission
- Author
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Ji, Jia-Bao, Guo, Zhaoheng, Driver, Taran, Trevisan, Cynthia S., Cesar, David, Cheng, Xinxin, Duris, Joseph, Franz, Paris L., Glownia, James, Gong, Xiaochun, Hammerland, Daniel, Han, Meng, Heck, Saijoscha, Hoffmann, Matthias, Kamalov, Andrei, Larsen, Kirk A., Li, Xiang, Lin, Ming-Fu, Liu, Yuchen, McCurdy, C. William, Obaid, Razib, ONeal, Jordan T., Rescigno, Thomas N., Robles, River R., Sudar, Nicholas, Walter, Peter, Wang, Anna L., Wang, Jun, Wolf, Thomas J. A., Zhang, Zhen, Ueda, Kiyoshi, Lucchese, Robert R., Marinelli, Agostino, Cryan, James P., and Wörner, Hans Jakob
- Subjects
Physics - Chemical Physics - Abstract
Attosecond photoemission or photoionization delays are a unique probe of the structure and the electronic dynamics of matter. However, spectral congestion and spatial delocalization of valence electron wave functions set fundamental limits to the complexity of systems that can be studied and the information that can be retrieved, respectively. Using attosecond X-ray pulses from LCLS, we demonstrate the key advantages of measuring core-level delays: the photoelectron spectra remain atom-like, the measurements become element specific and the observed scattering dynamics originate from a point-like source. We exploit these unique features to reveal the effects of electronegativity and symmetry on attosecond scattering dynamics by measuring the photoionization delays between N-1s and C-1s core shells of a series of aromatic azabenzene molecules. Remarkably, the delays systematically increase with the number of nitrogen atoms in the molecule and reveal multiple resonances. We identify two previously unknown mechanisms regulating the associated attosecond dynamics, namely the enhanced confinement of the trapped wavefunction with increasing electronegativity of the atoms and the decrease of the coupling strength among the photoemitted partial waves with increasing symmetry. This study demonstrates the unique opportunities opened by measurements of core-level photoionization delays for unravelling attosecond electron dynamics in complex matter.
- Published
- 2024
42. A Joint Communication and Computation Framework for Digital Twin over Wireless Networks
- Author
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Yang, Zhaohui, Chen, Mingzhe, Liu, Yuchen, and Zhang, Zhaoyang
- Subjects
Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
In this paper, the problem of low-latency communication and computation resource allocation for digital twin (DT) over wireless networks is investigated. In the considered model, multiple physical devices in the physical network (PN) needs to frequently offload the computation task related data to the digital network twin (DNT), which is generated and controlled by the central server. Due to limited energy budget of the physical devices, both computation accuracy and wireless transmission power must be considered during the DT procedure. This joint communication and computation problem is formulated as an optimization problem whose goal is to minimize the overall transmission delay of the system under total PN energy and DNT model accuracy constraints. To solve this problem, an alternating algorithm with iteratively solving device scheduling, power control, and data offloading subproblems. For the device scheduling subproblem, the optimal solution is obtained in closed form through the dual method. For the special case with one physical device, the optimal number of transmission times is reveled. Based on the theoretical findings, the original problem is transformed into a simplified problem and the optimal device scheduling can be found. Numerical results verify that the proposed algorithm can reduce the transmission delay of the system by up to 51.2\% compared to the conventional schemes.
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- 2024
43. Collaborative Reinforcement Learning Based Unmanned Aerial Vehicle (UAV) Trajectory Design for 3D UAV Tracking
- Author
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Zhu, Yujiao, Chen, Mingzhe, Wang, Sihua, Hu, Ye, Liu, Yuchen, and Yin, Changchuan
- Subjects
Computer Science - Multiagent Systems ,Computer Science - Machine Learning - Abstract
In this paper, the problem of using one active unmanned aerial vehicle (UAV) and four passive UAVs to localize a 3D target UAV in real time is investigated. In the considered model, each passive UAV receives reflection signals from the target UAV, which are initially transmitted by the active UAV. The received reflection signals allow each passive UAV to estimate the signal transmission distance which will be transmitted to a base station (BS) for the estimation of the position of the target UAV. Due to the movement of the target UAV, each active/passive UAV must optimize its trajectory to continuously localize the target UAV. Meanwhile, since the accuracy of the distance estimation depends on the signal-to-noise ratio of the transmission signals, the active UAV must optimize its transmit power. This problem is formulated as an optimization problem whose goal is to jointly optimize the transmit power of the active UAV and trajectories of both active and passive UAVs so as to maximize the target UAV positioning accuracy. To solve this problem, a Z function decomposition based reinforcement learning (ZD-RL) method is proposed. Compared to value function decomposition based RL (VD-RL), the proposed method can find the probability distribution of the sum of future rewards to accurately estimate the expected value of the sum of future rewards thus finding better transmit power of the active UAV and trajectories for both active and passive UAVs and improving target UAV positioning accuracy. Simulation results show that the proposed ZD-RL method can reduce the positioning errors by up to 39.4% and 64.6%, compared to VD-RL and independent deep RL methods, respectively.
- Published
- 2024
44. Self-supervised Learning for Electroencephalogram: A Systematic Survey
- Author
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Weng, Weining, Gu, Yang, Guo, Shuai, Ma, Yuan, Yang, Zhaohua, Liu, Yuchen, and Chen, Yiqiang
- Subjects
Electrical Engineering and Systems Science - Signal Processing ,Computer Science - Artificial Intelligence ,Computer Science - Machine Learning ,68-02 (Primarily), 68T01 (Secondary) ,I.2 ,J.3 ,I.5.4 - Abstract
Electroencephalogram (EEG) is a non-invasive technique to record bioelectrical signals. Integrating supervised deep learning techniques with EEG signals has recently facilitated automatic analysis across diverse EEG-based tasks. However, the label issues of EEG signals have constrained the development of EEG-based deep models. Obtaining EEG annotations is difficult that requires domain experts to guide collection and labeling, and the variability of EEG signals among different subjects causes significant label shifts. To solve the above challenges, self-supervised learning (SSL) has been proposed to extract representations from unlabeled samples through well-designed pretext tasks. This paper concentrates on integrating SSL frameworks with temporal EEG signals to achieve efficient representation and proposes a systematic review of the SSL for EEG signals. In this paper, 1) we introduce the concept and theory of self-supervised learning and typical SSL frameworks. 2) We provide a comprehensive review of SSL for EEG analysis, including taxonomy, methodology, and technique details of the existing EEG-based SSL frameworks, and discuss the difference between these methods. 3) We investigate the adaptation of the SSL approach to various downstream tasks, including the task description and related benchmark datasets. 4) Finally, we discuss the potential directions for future SSL-EEG research., Comment: 35 pages, 12 figures
- Published
- 2024
45. SemiSAM: Enhancing Semi-Supervised Medical Image Segmentation via SAM-Assisted Consistency Regularization
- Author
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Zhang, Yichi, Yang, Jin, Liu, Yuchen, Cheng, Yuan, and Qi, Yuan
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
Semi-supervised learning has attracted much attention due to its less dependence on acquiring abundant annotations from experts compared to fully supervised methods, which is especially important for medical image segmentation which typically requires intensive pixel/voxel-wise labeling by domain experts. Although semi-supervised methods can improve the performance by utilizing unlabeled data, there are still gaps between fully supervised methods under extremely limited annotation scenarios. In this paper, we propose a simple yet efficient strategy to explore the usage of the Segment Anything Model (SAM) for enhancing semi-supervised medical image segmentation. Concretely, the segmentation model trained with domain knowledge provides information for localization and generating input prompts to the SAM. Then the generated pseudo-labels of SAM are utilized as additional supervision to assist in the learning procedure of the semi-supervised framework. Extensive experiments demonstrate that SemiSAM significantly improves the performance of existing semi-supervised frameworks when only one or a few labeled images are available and shows strong efficiency as a plug-and-play strategy for semi-supervised medical image segmentation., Comment: Accept for BIBM 2024
- Published
- 2023
46. Magnetic-field tuning of the Casimir force
- Author
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Zhang, Yichi, Zhang, Hui, Wang, Xiuxia, Wang, Yiheng, Liu, Yuchen, Li, Shu, Zhang, Tianyi, Fan, Chuang, and Zeng, Changgan
- Published
- 2024
- Full Text
- View/download PDF
47. Anatomical study of the motor branches of the tibial nerve and incision design for hyperselective neurectomy
- Author
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Huang, Kun, Ye, Xuan, Zhu, Shuai, Liu, Yuchen, Sun, Fengchi, Su, Xiangmeng, Yin, Huawei, Xu, Wendong, and Shen, Yundong
- Published
- 2024
- Full Text
- View/download PDF
48. Low-frequency oscillation of train–network system considering traction power supply mode
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Liu, Yuchen, Lyu, Xiaoqin, Chang, Mingyuan, and Yang, Qiqi
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- 2024
- Full Text
- View/download PDF
49. A Joint Gradient and Loss Based Clustered Federated Learning Design
- Author
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Lin, Licheng, Chen, Mingzhe, Yang, Zhaohui, Wu, Yusen, and Liu, Yuchen
- Subjects
Computer Science - Machine Learning - Abstract
In this paper, a novel clustered FL framework that enables distributed edge devices with non-IID data to independently form several clusters in a distributed manner and implement FL training within each cluster is proposed. In particular, our designed clustered FL algorithm must overcome two challenges associated with FL training. First, the server has limited FL training information (i.e., the parameter server can only obtain the FL model information of each device) and limited computational power for finding the differences among a large amount of devices. Second, each device does not have the data information of other devices for device clustering and can only use global FL model parameters received from the server and its data information to determine its cluster identity, which will increase the difficulty of device clustering. To overcome these two challenges, we propose a joint gradient and loss based distributed clustering method in which each device determines its cluster identity considering the gradient similarity and training loss. The proposed clustering method not only considers how a local FL model of one device contributes to each cluster but also the direction of gradient descent thus improving clustering speed. By delegating clustering decisions to edge devices, each device can fully leverage its private data information to determine its own cluster identity, thereby reducing clustering overhead and improving overall clustering performance. Simulation results demonstrate that our proposed clustered FL algorithm can reduce clustering iterations by up to 99% compared to the existing baseline.
- Published
- 2023
50. From CLIP to DINO: Visual Encoders Shout in Multi-modal Large Language Models
- Author
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Jiang, Dongsheng, Liu, Yuchen, Liu, Songlin, Zhao, Jin'e, Zhang, Hao, Gao, Zhen, Zhang, Xiaopeng, Li, Jin, and Xiong, Hongkai
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
Multi-modal Large Language Models (MLLMs) have made significant strides in expanding the capabilities of Large Language Models (LLMs) through the incorporation of visual perception interfaces. Despite the emergence of exciting applications and the availability of diverse instruction tuning data, existing approaches often rely on CLIP or its variants as the visual branch, and merely extract features from the deep layers. However, these methods lack a comprehensive analysis of the visual encoders in MLLMs. In this paper, we conduct an extensive investigation into the effectiveness of different vision encoders within MLLMs. Our findings reveal that the shallow layer features of CLIP offer particular advantages for fine-grained tasks such as grounding and region understanding. Surprisingly, the vision-only model DINO, which is not pretrained with text-image alignment, demonstrates promising performance as a visual branch within MLLMs. By simply equipping it with an MLP layer for alignment, DINO surpasses CLIP in fine-grained related perception tasks. Building upon these observations, we propose a simple yet effective feature merging strategy, named COMM, that integrates CLIP and DINO with Multi-level features Merging, to enhance the visual capabilities of MLLMs. We evaluate COMM through comprehensive experiments on a wide range of benchmarks, including image captioning, visual question answering, visual grounding, and object hallucination. Experimental results demonstrate the superior performance of COMM compared to existing methods, showcasing its enhanced visual capabilities within MLLMs.
- Published
- 2023
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