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 Statistical Learning


Multi-Modal Machine Learning Framework for Predicting Early Recurrence of Brain Tumors Using MRI and Clinical Biomarkers

arXiv.org Artificial Intelligence

Despite advances in neurosurgical techniques, radiation therapy, and chemotherapeutic regimens, the prognosis for patients remains poor, with recurrence rates exceeding 70% within two years after surgical resection [70]. The high probability of early recurrence underscores the critical need for robust, patient-specific prognostic tools that can support personalized clinical decision-making. Accurate prediction of tumor recurrence is crucial for stratifying patients into appropriate risk categories, guiding adjuvant therapy choices, and optimizing postoperative surveillance [71]. Traditionally, recurrence risk assessments are based on clinical judgment informed by factors such as tumor size, histological grade, and extent of resection. However, these assessments often lack the granularity and precision needed for an individualized prognosis, particularly given the heterogeneity of tumor biology and interpatient variability [72]. Recent advances in multimodal machine learning (ML) have demonstrated the potential to address these challenges by integrating diverse data sources, as evidenced by emerging frameworks that leverage collaborative model optimization [73-75] and reward-driven paradigms for multimodal fusion [76,77]. Structural magnetic resonance imaging (MRI), especially contrast-enhanced T1-weighted imaging, is routinely employed in brain tumor diagnosis and follow-up, providing insights into tumor morphology and contrast uptake behavior [78].


MATL-DC: A Multi-domain Aggregation Transfer Learning Framework for EEG Emotion Recognition with Domain-Class Prototype under Unseen Targets

arXiv.org Artificial Intelligence

Emotion recognition based on electroencephalography (EEG) signals is increasingly becoming a key research hotspot in affective Brain-Computer Interfaces (aBCIs). However, the current transfer learning model greatly depends on the source domain and target domain data, which hinder the practical application of emotion recognition. Therefore, we propose a Multi-domain Aggregation Transfer Learning framework for EEG emotion recognition with Domain-Class prototype under unseen targets (MATL-DC). We design the feature decoupling module to decouple class-invariant domain features from domain-invariant class features from shallow features. In the model training stage, the multi-domain aggregation mechanism aggregates the domain feature space to form a superdomain, which enhances the characteristics of emotional EEG signals. In each superdomain, we further extract the class prototype representation by class features. In addition, we adopt the pairwise learning strategy to transform the sample classification problem into the similarity problem between sample pairs, which effectively alleviates the influence of label noise. It is worth noting that the target domain is completely unseen during the training process. In the inference stage, we use the trained domain-class prototypes for inference, and then realize emotion recognition. We rigorously validate it on the publicly available databases (SEED, SEED-IV and SEED-V). The results show that the accuracy of MATL-DC model is 84.70\%, 68.11\% and 61.08\%, respectively. MATL-DC achieves comparable or even better performance than methods that rely on both source and target domains. The source code is available at https://github.com/WuCB-BCI/MATL-DC.


A novel parameter estimation method for pneumatic soft hand control applying logarithmic decrement for pseudo rigid body modeling

arXiv.org Artificial Intelligence

The rapid advancement in physical human-robot interaction (HRI) has accelerated the development of soft robot designs and controllers. Controlling soft robots, especially soft hand grasping, is challenging due to their continuous deformation, motivating the use of reduced model-based controllers for real-time dynamic performance. Most existing models, however, suffer from computational inefficiency and complex parameter identification, limiting their real-time applicability. To address this, we propose a paradigm coupling Pseudo-Rigid Body Modeling with the Logarithmic Decrement Method for parameter estimation (PRBM plus LDM). Using a soft robotic hand test bed, we validate PRBM plus LDM for predicting position and force output from pressure input and benchmark its performance. We then implement PRBM plus LDM as the basis for closed-loop position and force controllers. Compared to a simple PID controller, the PRBM plus LDM position controller achieves lower error (average maximum error across all fingers: 4.37 degrees versus 20.38 degrees). For force control, PRBM plus LDM outperforms constant pressure grasping in pinching tasks on delicate objects: potato chip 86 versus 82.5, screwdriver 74.42 versus 70, brass coin 64.75 versus 35. These results demonstrate PRBM plus LDM as a computationally efficient and accurate modeling technique for soft actuators, enabling stable and flexible grasping with precise force regulation.


A Class of Random-Kernel Network Models

arXiv.org Artificial Intelligence

We introduce random-kernel networks, a multilayer extension of random feature models where depth is created by deterministic kernel composition and randomness enters only in the outermost layer. We prove that deeper constructions can approximate certain functions with fewer Monte Carlo samples than any shallow counterpart, establishing a depth separation theorem in sample complexity.


Chronotome: Real-Time Topic Modeling for Streaming Embedding Spaces

arXiv.org Artificial Intelligence

Harvard University Figure 1: T o visualize how topics evolve in real time, we create a rotatable embedding space where time is encoded along the Z-axis. We provide three preset views to help users explore topic clusters from different perspectives: (A) Front View (overall clusters), (B) Iso View (clusters over time), and (C) Side View (clusters over time). Here, each point represents an image from a dataset of Picasso's paintings, batched into 5-year intervals. Many real-world datasets - from an artist's body of work to a person's social media history - exhibit meaningful semantic changes over time that are difficult to capture with existing dimensionality reduction methods. To address this gap, we introduce a visualization technique that combines force-based projection and streaming clustering methods to build a spatial-temporal map of embeddings. We demonstrate the utility of our approach through use cases on text and image data, showing how it offers a new lens for understanding the aesthetics and semantics of temporal datasets.


Reinforcement Learning Driven Generalizable Feature Representation for Cross-User Activity Recognition

arXiv.org Artificial Intelligence

Human Activity Recognition (HAR) using wearable sensors is crucial for healthcare, fitness tracking, and smart environments, yet cross-user variability -- stemming from diverse motion patterns, sensor placements, and physiological traits -- hampers generalization in real-world settings. Conventional supervised learning methods often overfit to user-specific patterns, leading to poor performance on unseen users. Existing domain generalization approaches, while promising, frequently overlook temporal dependencies or depend on impractical domain-specific labels. We propose Temporal-Preserving Reinforcement Learning Domain Generalization (TPRL-DG), a novel framework that redefines feature extraction as a sequential decision-making process driven by reinforcement learning. TPRL-DG leverages a Transformer-based autoregressive generator to produce temporal tokens that capture user-invariant activity dynamics, optimized via a multi-objective reward function balancing class discrimination and cross-user invariance. Key innovations include: (1) an RL-driven approach for domain generalization, (2) autoregressive tokenization to preserve temporal coherence, and (3) a label-free reward design eliminating the need for target user annotations. Evaluations on the DSADS and PAMAP2 datasets show that TPRL-DG surpasses state-of-the-art methods in cross-user generalization, achieving superior accuracy without per-user calibration. By learning robust, user-invariant temporal patterns, TPRL-DG enables scalable HAR systems, facilitating advancements in personalized healthcare, adaptive fitness tracking, and context-aware environments.


Quantum-based QoE Optimization in Advanced Cellular Networks: Integration and Cloud Gaming Use Case

arXiv.org Artificial Intelligence

This work explores the integration of Quantum Machine Learning (QML) and Quantum-Inspired (QI) techniques for optimizing end-to-end (E2E) network services in telecommunication systems, particularly focusing on 5G networks and beyond. The application of QML and QI algorithms is investigated, comparing their performance with classical Machine Learning (ML) approaches. The present study employs a hybrid framework combining quantum and classical computing leveraging the strengths of QML and QI, without the penalty of quantum hardware availability. This is particularized for the optimization of the Quality of Experience (QoE) over cellular networks. The framework comprises an estimator for obtaining the expected QoE based on user metrics, service settings, and cell configuration, and an optimizer that uses the estimation to choose the best cell and service configuration. Although the approach is applicable to any QoE-based network management, its implementation is particularized for the optimization of network configurations for Cloud Gaming services. Then, it is evaluated via performance metrics such as accuracy and model loading and inference times for the estimator, and time to solution and solution score for the optimizer. The results indicate that QML models achieve similar or superior accuracy to classical ML models for estimation, while decreasing inference and loading times. Furthermore, potential for better performance is observed for higher-dimensional data, highlighting promising results for higher complexity problems. Thus, the results demonstrate the promising potential of QML in advancing network optimization, although challenges related to data availability and integration complexities between quantum and classical ML are identified as future research lines.


Online Decentralized Federated Multi-task Learning With Trustworthiness in Cyber-Physical Systems

arXiv.org Artificial Intelligence

Multi-task learning is an effective way to address the challenge of model personalization caused by high data heterogeneity in federated learning. However, extending multi-task learning to the online decentralized federated learning setting is yet to be explored. The online decentralized federated learning setting considers many real-world applications of federated learning, such as autonomous systems, where clients communicate peer-to-peer and the data distribution of each client is time-varying. A more serious problem in real-world applications of federated learning is the presence of Byzantine clients. Byzantine-resilient approaches used in federated learning work only when the number of Byzantine clients is less than one-half the total number of clients. Yet, it is difficult to put a limit on the number of Byzantine clients within a system in reality. However, recent work in robotics shows that it is possible to exploit cyber-physical properties of a system to predict clients' behavior and assign a trust probability to received signals. This can help to achieve resiliency in the presence of a dominating number of Byzantine clients. Therefore, in this paper, we develop an online decentralized federated multi-task learning algorithm to provide model personalization and resiliency when the number of Byzantine clients dominates the number of honest clients. Our proposed algorithm leverages cyber-physical properties, such as the received signal strength in wireless systems or side information, to assign a trust probability to local models received from neighbors in each iteration. Our simulation results show that the proposed algorithm performs close to a Byzantine-free setting.


IoT-based Noise Monitoring using Mobile Nodes for Smart Cities

arXiv.org Artificial Intelligence

--Urban noise pollution poses a significant threat to public health, yet existing monitoring infrastructures offer limited spatial coverage and adaptability. This paper presents a scalable, low-cost, IoT -based, real-time environmental noise monitoring solution using mobile nodes ( sensor nodes on a moving vehicle). The system utilizes a low-cost sound sensor integrated with GPS-enabled modules to collect geotagged noise data at one-second intervals. The sound nodes are calibrated against a reference sound level meter in a laboratory setting to ensure accuracy using various machine learning (ML) algorithms such as Simple Linear Regression (SLR), Multiple Linear Regression (MLR), Polynomial Regression (PR), Segmented Regression (SR), Support V ector Regression (SVR), Decision Tree (DT), and Random Forest Regression (RFR). While laboratory calibration demonstrates high accuracy, it is shown that the performance of the nodes degrades during data collection in a moving vehicle. T o address this, it is demonstrated that the calibration must be performed on the IoT -based node based on the data collected in a moving environment along with the reference device. The system was deployed in Hyderabad, India, through three measurement campaigns across 27 days, capturing 436,420 data points. Results highlight temporal and spatial noise variations across weekdays, weekends, and during Diwali. Incorporating vehicular velocity into the calibration significantly improves accuracy. The proposed system demonstrates the potential for widespread deployment of IoT -based noise sensing networks in smart cities, enabling effective noise pollution management and urban planning. OISE pollution, also known as environmental noise or sound pollution, refers to unwanted or excessive sound that disrupts human activities and negatively impacts human health [1]. The known sources of noise pollution include transportation (such as road traffic), industrial activities, construction, and urban crowding [2].


Structure and Destructure: Dual Forces in the Making of Knowledge Engines

arXiv.org Artificial Intelligence

The making of knowledge engines in natural language processing has been shaped by two seemingly distinct paradigms: one grounded in structure, the other driven by massively available unstructured data. The structured paradigm leverages predefined symbolic interactions, such as knowledge graphs, as priors and designs models to capture them. In contrast, the unstructured paradigm centers on scaling transformer architectures with increasingly vast data and model sizes, as seen in modern large language models. Despite their divergence, this thesis seeks to establish conceptual connections bridging these paradigms. Two complementary forces, structure and destructure, emerge across both paradigms: structure organizes seen symbolic interactions, while destructure, through periodic embedding resets, improves model plasticity and generalization to unseen scenarios. These connections form a new recipe for developing general knowledge engines that can support transparent, controllable, and adaptable intelligent systems.