Statistical Learning
Data-Driven, Parameterized Reduced-order Models for Predicting Distortion in Metal 3D Printing
Deo, Indu Kant, Choi, Youngsoo, Khairallah, Saad A., Reikher, Alexandre, Strantza, Maria
In Laser Powder Bed Fusion (LPBF), the applied laser energy produces high thermal gradients that lead to unacceptable final part distortion. Accurate distortion prediction is essential for optimizing the 3D printing process and manufacturing a part that meets geometric accuracy requirements. This study introduces data-driven parameterized reduced-order models (ROMs) to predict distortion in LPBF across various machine process settings. We propose a ROM framework that combines Proper Orthogonal Decomposition (POD) with Gaussian Process Regression (GPR) and compare its performance against a deep-learning based parameterized graph convolutional autoencoder (GCA). The POD-GPR model demonstrates high accuracy, predicting distortions within $\pm0.001mm$, and delivers a computational speed-up of approximately 1800x.
Accelerated Gradient Tracking over Time-varying Graphs for Decentralized Optimization
Decentralized optimization over time-varying graphs has been increasingly common in modern machine learning with massive data stored on millions of mobile devices, such as in federated learning. This paper revisits the widely used accelerated gradient tracking and extends it to time-varying graphs. We prove that the practical single loop accelerated gradient tracking needs $O((\frac{\gamma}{1-\sigma_{\gamma}})^2\sqrt{\frac{L}{\epsilon}})$ and $O((\frac{\gamma}{1-\sigma_{\gamma}})^{1.5}\sqrt{\frac{L}{\mu}}\log\frac{1}{\epsilon})$ iterations to reach an $\epsilon$-optimal solution over time-varying graphs when the problems are nonstrongly convex and strongly convex, respectively, where $\gamma$ and $\sigma_{\gamma}$ are two common constants charactering the network connectivity, $L$ and $\mu$ are the smoothness and strong convexity constants, respectively, and one iteration corresponds to one gradient oracle call and one communication round. Our convergence rates improve significantly over the ones of $O(\frac{1}{\epsilon^{5/7}})$ and $O((\frac{L}{\mu})^{5/7}\frac{1}{(1-\sigma)^{1.5}}\log\frac{1}{\epsilon})$, respectively, which were proved in the original literature of accelerated gradient tracking only for static graphs, where $\frac{\gamma}{1-\sigma_{\gamma}}$ equals $\frac{1}{1-\sigma}$ when the network is time-invariant. When combining with a multiple consensus subroutine, the dependence on the network connectivity constants can be further improved to $O(1)$ and $O(\frac{\gamma}{1-\sigma_{\gamma}})$ for the gradient oracle and communication round complexities, respectively. When the network is static, by employing the Chebyshev acceleration, our complexities exactly match the lower bounds without hiding any poly-logarithmic factor for both nonstrongly convex and strongly convex problems.
Early Dementia Detection Using Multiple Spontaneous Speech Prompts: The PROCESS Challenge
Tao, Fuxiang, Mirheidari, Bahman, Pahar, Madhurananda, Young, Sophie, Xiao, Yao, Elghazaly, Hend, Peters, Fritz, Illingworth, Caitlin, Braun, Dorota, O'Malley, Ronan, Bell, Simon, Blackburn, Daniel, Haider, Fasih, Luz, Saturnino, Christensen, Heidi
Second, the audio quality of the data is poor and does not represent the quality that it is possible to Dementia is associated with various cognitive impairments achieve even with current, standard consumer-based devices and typically manifests only after significant progression, like modern laptops. These factors underscore the necessity making intervention at this stage often ineffective. To address for new data sets to ensure the continued advancement and this issue, the Prediction and Recognition of Cognitive accuracy of research in this field. Decline through Spontaneous Speech (PROCESS) Signal The PROCESS Signal Processing Grand Challenge aims Processing Grand Challenge invites participants to focus on to establish a platform for contributions and discussions on early-stage dementia detection. We provide a new spontaneous early-stage dementia detection using speech signal processing speech corpus for this challenge. This corpus includes and Artificial Intelligence (AI) models. To support this, answers from three prompts designed by neurologists to better we provide a state-of-the-art corpus covering a broader range capture the cognition of speakers. Our baseline models of diagnostic classes for different subtypes of early-stage achieved an F1-score of 55.0% on the classification task and dementia, including mild cognitive impairment (MCI).
An Experimental Evaluation of Imputation Models for Spatial-Temporal Traffic Data
Guo, Shengnan, Wei, Tonglong, Huang, Yiheng, Zhao, Miaomiao, Chen, Ran, Lin, Yan, Lin, Youfang, Wan, Huaiyu
Traffic data imputation is a critical preprocessing step in intelligent transportation systems, enabling advanced transportation services. Despite significant advancements in this field, selecting the most suitable model for practical applications remains challenging due to three key issues: 1) incomprehensive consideration of missing patterns that describe how data loss along spatial and temporal dimensions, 2) the lack of test on standardized datasets, and 3) insufficient evaluations. To this end, we first propose practice-oriented taxonomies for missing patterns and imputation models, systematically identifying all possible forms of real-world traffic data loss and analyzing the characteristics of existing models. Furthermore, we introduce a unified benchmarking pipeline to comprehensively evaluate 10 representative models across various missing patterns and rates. This work aims to provide a holistic understanding of traffic data imputation research and serve as a practical guideline.
Machine learning algorithms to predict the risk of rupture of intracranial aneurysms: a systematic review
Daga, Karan, Agarwal, Siddharth, Moti, Zaeem, Lee, Matthew BK, Din, Munaib, Wood, David, Modat, Marc, Booth, Thomas C
Purpose: Subarachnoid haemorrhage is a potentially fatal consequence of intracranial aneurysm rupture, however, it is difficult to predict if aneurysms will rupture. Prophylactic treatment of an intracranial aneurysm also involves risk, hence identifying rupture-prone aneurysms is of substantial clinical importance. This systematic review aims to evaluate the performance of machine learning algorithms for predicting intracranial aneurysm rupture risk. Methods: MEDLINE, Embase, Cochrane Library and Web of Science were searched until December 2023. Studies incorporating any machine learning algorithm to predict the risk of rupture of an intracranial aneurysm were included. Risk of bias was assessed using the Prediction Model Risk of Bias Assessment Tool (PROBAST). PROSPERO registration: CRD42023452509. Results: Out of 10,307 records screened, 20 studies met the eligibility criteria for this review incorporating a total of 20,286 aneurysm cases. The machine learning models gave a 0.66-0.90 range for performance accuracy. The models were compared to current clinical standards in six studies and gave mixed results. Most studies posed high or unclear risks of bias and concerns for applicability, limiting the inferences that can be drawn from them. There was insufficient homogenous data for a meta-analysis. Conclusions: Machine learning can be applied to predict the risk of rupture for intracranial aneurysms. However, the evidence does not comprehensively demonstrate superiority to existing practice, limiting its role as a clinical adjunct. Further prospective multicentre studies of recent machine learning tools are needed to prove clinical validation before they are implemented in the clinic.
Ethical and Scalable Automation: A Governance and Compliance Framework for Business Applications
The popularisation of applying AI in businesses poses significant challenges relating to ethical principles, governance, and legal compliance. Although businesses have embedded AI into their day-to-day processes, they lack a unified approach for mitigating its potential risks. This paper introduces a framework ensuring that AI must be ethical, controllable, viable, and desirable. Balancing these factors ensures the design of a framework that addresses its trade-offs, such as balancing performance against explainability. A successful framework provides practical advice for businesses to meet regulatory requirements in sectors such as finance and healthcare, where it is critical to comply with standards like GPDR and the EU AI Act. Different case studies validate this framework by integrating AI in both academic and practical environments. For instance, large language models are cost-effective alternatives for generating synthetic opinions that emulate attitudes to environmental issues. These case studies demonstrate how having a structured framework could enhance transparency and maintain performance levels as shown from the alignment between synthetic and expected distributions. This alignment is quantified using metrics like Chi-test scores, normalized mutual information, and Jaccard indexes. Future research should explore the framework's empirical validation in diverse industrial settings further, ensuring the model's scalability and adaptability.
Visual Error Patterns in Multi-Modal AI: A Statistical Approach
Multi-modal large language models (MLLMs), such as GPT-4o, excel at integrating text and visual data but face systematic challenges when interpreting ambiguous or incomplete visual stimuli. This study leverages statistical modeling to analyze the factors driving these errors, using a dataset of geometric stimuli characterized by features like 3D, rotation, and missing face/side. We applied parametric methods, non-parametric methods, and ensemble techniques to predict classification errors, with the non-linear gradient boosting model achieving the highest performance (AUC=0.85) during cross-validation. Feature importance analysis highlighted difficulties in depth perception and reconstructing incomplete structures as key contributors to misclassification. These findings demonstrate the effectiveness of statistical approaches for uncovering limitations in MLLMs and offer actionable insights for enhancing model architectures by integrating contextual reasoning mechanisms.
Labeling questions inside issue trackers
One of the issues faced by the maintainers of popular open source software is the triage of newly reported issues. Many of the issues submitted to issue trackers are questions. Many people ask questions on issue trackers about their problem instead of using a proper QA website like StackOverflow. This may seem insignificant but for many of the big projects with thousands of users, this leads to spamming of the issue tracker. Reading and labeling these unrelated issues manually is a serious time consuming task and these unrelated questions add to the burden. In fact, most often maintainers demand to not submit questions in the issue tracker. To address this problem, first, we leveraged dozens of patterns to clean text of issues, we removed noises like logs, stack traces, environment variables, error messages, etc. Second, we have implemented a classification-based approach to automatically label unrelated questions. Empirical evaluations on a dataset of more than 102,000 records show that our approach can label questions with an accuracy of over 81%.
TelOps: AI-driven Operations and Maintenance for Telecommunication Networks
Yang, Yuqian, Yang, Shusen, Zhao, Cong, Xu, Zongben
Telecommunication Networks (TNs) have become the most important infrastructure for data communications over the last century. Operations and maintenance (O&M) is extremely important to ensure the availability, effectiveness, and efficiency of TN communications. Different from the popular O&M technique for IT systems (e.g., the cloud), artificial intelligence for IT Operations (AIOps), O&M for TNs meets the following three fundamental challenges: topological dependence of network components, highly heterogeneous software, and restricted failure data. This article presents TelOps, the first AI-driven O&M framework for TNs, systematically enhanced with mechanism, data, and empirical knowledge. We provide a comprehensive comparison between TelOps and AIOps, and conduct a proof-of-concept case study on a typical O&M task (failure diagnosis) for a real industrial TN. As the first systematic AI-driven O&M framework for TNs, TelOps opens a new door to applying AI techniques to TN automation.
HEAL: Hierarchical Embedding Alignment Loss for Improved Retrieval and Representation Learning
Bhattarai, Manish, Barron, Ryan, Eren, Maksim, Vu, Minh, Grantcharov, Vesselin, Boureima, Ismael, Stanev, Valentin, Matuszek, Cynthia, Valtchinov, Vladimir, Rasmussen, Kim, Alexandrov, Boian
Retrieval-Augmented Generation (RAG) enhances Large Language Models (LLMs) by integrating external document retrieval to provide domain-specific or up-to-date knowledge. The effectiveness of RAG depends on the relevance of retrieved documents, which is influenced by the semantic alignment of embeddings with the domain's specialized content. Although full fine-tuning can align language models to specific domains, it is computationally intensive and demands substantial data. This paper introduces Hierarchical Embedding Alignment Loss (HEAL), a novel method that leverages hierarchical fuzzy clustering with matrix factorization within contrastive learning to efficiently align LLM embeddings with domain-specific content. HEAL computes level/depth-wise contrastive losses and incorporates hierarchical penalties to align embeddings with the underlying relationships in label hierarchies. This approach enhances retrieval relevance and document classification, effectively reducing hallucinations in LLM outputs. In our experiments, we benchmark and evaluate HEAL across diverse domains, including Healthcare, Material Science, Cyber-security, and Applied Maths.