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Using Synthetic Data to estimate the True Error is theoretically and practically doable
Thanh, Hai Hoang, Nguyen, Duy-Tung, Tran, Hung The, Than, Khoat
Accurately evaluating model performance is crucial for deploying machine learning systems in real-world applications. Traditional methods often require a sufficiently large labeled test set to ensure a reliable evaluation. However, in many contexts, a large labeled dataset is costly and labor-intensive. Therefore, we sometimes have to do evaluation by a few labeled samples, which is theoretically challenging. Recent advances in generative models offer a promising alternative by enabling the synthesis of high-quality data. In this work, we make a systematic investigation about the use of synthetic data to estimate the test error of a trained model under limited labeled data conditions. To this end, we develop novel generalization bounds that take synthetic data into account. Those bounds suggest novel ways to optimize synthetic samples for evaluation and theoretically reveal the significant role of the generator's quality. Inspired by those bounds, we propose a theoretically grounded method to generate optimized synthetic data for model evaluation. Experimental results on simulation and tabular datasets demonstrate that, compared to existing baselines, our method achieves accurate and more reliable estimates of the test error.
Motion-Robust Multimodal Fusion of PPG and Accelerometer Signals for Three-Class Heart Rhythm Classification
Zhao, Yangyang, Kaisti, Matti, Lahdenoja, Olli, Koivisto, Tero
Atrial fibrillation (AF) is a leading cause of stroke and mortality, particularly in elderly patients. Wrist-worn photoplethysmography (PPG) enables non-invasive, continuous rhythm monitoring, yet suffers from significant vulnerability to motion artifacts and physiological noise. Many existing approaches rely solely on single-channel PPG and are limited to binary AF detection, often failing to capture the broader range of arrhythmias encountered in clinical settings. We introduce RhythmiNet, a residual neural network enhanced with temporal and channel attention modules that jointly leverage PPG and accelerometer (ACC) signals. The model performs three-class rhythm classification: AF, sinus rhythm (SR), and Other. To assess robustness across varying movement conditions, test data are stratified by accelerometer-based motion intensity percentiles without excluding any segments. RhythmiNet achieved a 4.3% improvement in macro-AUC over the PPG-only baseline. In addition, performance surpassed a logistic regression model based on handcrafted HRV features by 12%, highlighting the benefit of multimodal fusion and attention-based learning in noisy, real-world clinical data.
URDF-Anything: Constructing Articulated Objects with 3D Multimodal Language Model
Li, Zhe, Bai, Xiang, Zhang, Jieyu, Wu, Zhuangzhe, Xu, Che, Li, Ying, Hou, Chengkai, Zhang, Shanghang
Constructing accurate digital twins of articulated objects is essential for robotic simulation training and embodied AI world model building, yet historically requires painstaking manual modeling or multi-stage pipelines. In this work, we propose \textbf{URDF-Anything}, an end-to-end automatic reconstruction framework based on a 3D multimodal large language model (MLLM). URDF-Anything utilizes an autoregressive prediction framework based on point-cloud and text multimodal input to jointly optimize geometric segmentation and kinematic parameter prediction. It implements a specialized $[SEG]$ token mechanism that interacts directly with point cloud features, enabling fine-grained part-level segmentation while maintaining consistency with the kinematic parameter predictions. Experiments on both simulated and real-world datasets demonstrate that our method significantly outperforms existing approaches regarding geometric segmentation (mIoU 17\% improvement), kinematic parameter prediction (average error reduction of 29\%), and physical executability (surpassing baselines by 50\%). Notably, our method exhibits excellent generalization ability, performing well even on objects outside the training set. This work provides an efficient solution for constructing digital twins for robotic simulation, significantly enhancing the sim-to-real transfer capability.
pacSTL: PAC-Bounded Signal Temporal Logic from Data-Driven Reachability Analysis
Dietrich, Elizabeth, Krasowski, Hanna, Gezer, Emir Cem, Skjetne, Roger, Sรธrensen, Asgeir Johan, Arcak, Murat
Real-world robotic systems must comply with safety requirements in the presence of uncertainty. To define and measure requirement adherence, Signal Temporal Logic (STL) offers a mathematically rigorous and expressive language. However, standard STL cannot account for uncertainty. We address this problem by presenting pacSTL, a framework that combines Probably Approximately Correct (PAC) bounded set predictions with an interval extension of STL through optimization problems on the atomic proposition level. pacSTL provides PAC-bounded robustness intervals on the specification level that can be utilized in monitoring. We demonstrate the effectiveness of this approach through maritime navigation and analyze the efficiency and scalability of pacSTL through simulation and real-world experimentation on model vessels.
The Biased Oracle: Assessing LLMs' Understandability and Empathy in Medical Diagnoses
Yao, Jianzhou, Liu, Shunchang, Drui, Guillaume, Pettersson, Rikard, Blasimme, Alessandro, Kijewski, Sara
Large language models (LLMs) show promise for supporting clinicians in diagnostic communication by generating explanations and guidance for patients. Yet their ability to produce outputs that are both understandable and empathetic remains uncertain. We evaluate two leading LLMs on medical diagnostic scenarios, assessing understandability using readability metrics as a proxy and empathy through LLM-as-a-Judge ratings compared to human evaluations. The results indicate that LLMs adapt explanations to socio-demographic variables and patient conditions. However, they also generate overly complex content and display biased affective empathy, leading to uneven accessibility and support. These patterns underscore the need for systematic calibration to ensure equitable patient communication. The code and data are released: https://github.com/Jeffateth/Biased_Oracle
Dynamic Logic of Trust-Based Beliefs
Jiang, Junli, Naumov, Pavel, Zhang, Wenxuan
Traditionally, an agent's beliefs would come from what the agent can see, hear, or sense. In the modern world, beliefs are often based on the data available to the agents. In this work, we investigate a dynamic logic of such beliefs that incorporates public announcements of data. The main technical contribution is a sound and complete axiomatisation of the interplay between data-informed beliefs and data announcement modalities. We also describe a non-trivial polynomial model checking algorithm for this logical system.
Android Malware Detection: A Machine Leaning Approach
-- This study examines machine learning techniques like Decision Trees, Support V ector Machines, Logistic Regression, Neural Networks, and ensemble methods to detect Android malware. The study evaluates these models on a dataset of Android applications and analyzes their accuracy, efficiency, and real-world applicability. Key findings show that ensemble methods demonstrate superior performance, but there are trade-offs between model interpretability, efficiency, and accuracy. Given its increasing threat, the insights guide future research and practical use of ML to combat Android malware. I. INTRODUCTION Smartphones have brought in a new era of connectivity, convenience, and innovation, with Android being the most widely used mobile operating system [1], [2]. However, this ubiquity has come with challenges. The background of Android's ecosystem makes clear that the characteristics that make Android popular also leave it vulnerable to malicious activities. Specifically, Android's open-source nature, vast user base, and easy application distribution and installation have created an environment where cybercriminals can thrive. Thus, it is essential to understand the Android ecosystem's unique landscape to address the severe threat of Android malware. The following section sets the stage for exploring advanced malware detection techniques for Android devices in later sections. A. Background The extensive adoption of Android operating systems, with their open-source nature and customization capabilities, has led to them becoming a primary target for cybercriminals. Android's vast and diverse application ecosystem presents significant security challenges, as malicious applications can masquerade as legitimate ones, exploiting vulnerabilities and employing social engineering tactics [1]-[3]. These malicious activities include stealing sensitive information, sending premium-rate SMS messages, and installing additional payloads [4]-[5].
Assessing LLM Reasoning Steps via Principal Knowledge Grounding
Hwang, Hyeon, Cho, Yewon, Yoon, Chanwoong, Park, Yein, Song, Minju, Lee, Kyungjae, Kim, Gangwoo, Kang, Jaewoo
Step-by-step reasoning has become a standard approach for large language models (LLMs) to tackle complex tasks. While this paradigm has proven effective, it raises a fundamental question: How can we verify that an LLM's reasoning is accurately grounded in knowledge? To address this question, we introduce a novel evaluation suite that systematically assesses the knowledge grounding of intermediate reasoning. Our framework comprises three key components. (1) Principal Knowledge Collection, a large-scale repository of atomic knowledge essential for reasoning. Based on the collection, we propose (2) knowledge-grounded evaluation metrics designed to measure how well models recall and apply prerequisite knowledge in reasoning. These metrics are computed by our (3) evaluator LLM, a lightweight model optimized for cost-effective and reliable metric computation. Our evaluation suite demonstrates remarkable effectiveness in identifying missing or misapplied knowledge elements, providing crucial insights for uncovering fundamental reasoning deficiencies in LLMs. Beyond evaluation, we demonstrate how these metrics can be integrated into preference optimization, showcasing further applications of knowledge-grounded evaluation.
Occlusion-Aware Diffusion Model for Pedestrian Intention Prediction
Liu, Yu, Liu, Zhijie, Yang, Zedong, Li, You-Fu, Kong, He
Abstract--Predicting pedestrian crossing intentions is crucial for the navigation of mobile robots and intelligent vehicles. Although recent deep learning-based models have shown significant success in forecasting intentions, few consider incomplete observation under occlusion scenarios. T o tackle this challenge, we propose an Occlusion-A ware Diffusion Model (ODM) that reconstructs occluded motion patterns and leverages them to guide future intention prediction. During the denoising stage, we introduce an occlusion-aware diffusion transformer architecture to estimate noise features associated with occluded patterns, thereby enhancing the model's ability to capture contextual relationships in occluded semantic scenarios. Furthermore, an occlusion mask-guided reverse process is introduced to effectively utilize observation information, reducing the accumulation of prediction errors and enhancing the accuracy of reconstructed motion features. The performance of the proposed method under various occlusion scenarios is comprehensively evaluated and compared with existing methods on popular benchmarks, namely PIE and JAAD. Extensive experimental results demonstrate that the proposed method achieves more robust performance than existing methods in the literature. ITH the rapid advancement of intelligent sensing and computing technologies, much progress has been made in recent years in developing autonomous vehicles to enhance traffic efficiency and road safety. To prevent collisions, path planning of autonomous vehicles [1], [2] is essential, requiring an understanding of interactions between road users and the ability to forecast their potential actions [3]-[5]. This manuscript has been accepted to the IEEE Transactions on Intelligent Transportation Systems as a regular paper. Y u Liu is also with the Department of Mechanical Engineering, City University of Hong Kong, Hong Kong SAR, China. Y ou-Fu Li is with the Department of Mechanical Engineering, City University of Hong Kong, Hong Kong SAR, China. The typical scenario of visual occlusion is illustrated here. Solid green lines represent the parts of the observation that are within the field of view and visible, while dashed red lines indicate positional features that are undetectable due to occlusion.
MULTI-Bench: A Multi-Turn Interactive Benchmark for Assessing Emotional Intelligence ability of Spoken Dialogue Models
Deng, Yayue, Hu, Guoqiang, Sun, Haiyang, Zhang, Xiangyu, Zhang, Haoyang, Tian, Fei, Yang, Xuerui, Yu, Gang, Chng, Eng Siong
Spoken Dialogue Models (SDMs) have advanced rapidly, yet their ability to sustain genuinely interactive multi-turn conversations remains underexplored, as most benchmarks focus on single-turn exchanges. We introduce Multi-Bench, the first benchmark explicitly designed to evaluate SDMs in multi-turn interactive dialogue with an emphasis on emotional intelligence. Multi-Bench employs a hierarchical structure with a basic track for emotion understanding and reasoning and an advanced track for emotion support and application. It comprises five carefully designed tasks and about 3.2K samples, ranging from emotion recognition to complex reasoning and interactive dialogue, supported by a reproducible evaluation framework. We evaluate six representative SDMs on eight subsets of Multi-Bench. Results show that while current SDMs achieve good performance on basic understanding tasks, they still have room for improvement in advanced multi-turn interactive dialogue and reasoning-related tasks, particularly in emotion awareness and application.