{"title":"Calibrated Probabilistic Forecasts for Arbitrary Sequences.","authors":"Charles Marx, Volodymyr Kuleshov, Stefano Ermon","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Real-world data streams can change unpredictably due to distribution shifts, feedback loops and adversarial actors, which challenges the validity of forecasts. We present a forecasting framework ensuring valid uncertainty estimates regardless of how data evolves. Leveraging the concept of Blackwell approachability from game theory, we introduce a forecasting framework that guarantees calibrated uncertainties for outcomes in any compact space (e.g., classification or bounded regression). We extend this framework to recalibrate existing forecasters, guaranteeing calibration without sacrificing predictive performance. We implement both general-purpose gradient-based algorithms and algorithms optimized for popular special cases of our framework. Empirically, our algorithms improve calibration and downstream decision-making for energy systems.</p>","PeriodicalId":75238,"journal":{"name":"Transactions on machine learning research","volume":"2025 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12975122/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147438258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Travis E Gibson, Sawal Acharya, Anjali Parashar, Joseph E Gaudio, Anuradha M Annaswamy
{"title":"On the stability of gradient descent with second order dynamics for time-varying cost functions.","authors":"Travis E Gibson, Sawal Acharya, Anjali Parashar, Joseph E Gaudio, Anuradha M Annaswamy","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Gradient based optimization algorithms deployed in Machine Learning (ML) applications are often analyzed and compared by their convergence rates or regret bounds. While these rates and bounds convey valuable information they don't always directly translate to stability guarantees. Stability and similar concepts, like robustness, will become ever more important as we move towards deploying models in real-time and safety critical systems. In this work we build upon the results in Gaudio et al. 2021 and Moreu & Annaswamy 2022 for gradient descent with second order dynamics when applied to explicitly time varying cost functions and provide more general stability guarantees. These more general results can aid in the design and certification of these optimization schemes so as to help ensure safe and reliable deployment for real-time learning applications. We also hope that the techniques provided here will stimulate and cross-fertilize the analysis that occurs on the same algorithms from the online learning and stochastic optimization communities.</p>","PeriodicalId":75238,"journal":{"name":"Transactions on machine learning research","volume":"2025 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12284918/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144700595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Balanced Mixed-Type Tabular Data Synthesis with Diffusion Models.","authors":"Zeyu Yang, Han Yu, Peikun Guo, Khadija Zanna, Xiaoxue Yang, Akane Sano","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Diffusion models have emerged as a robust framework for various generative tasks, including tabular data synthesis. However, current tabular diffusion models tend to inherit bias in the training dataset and generate biased synthetic data, which may influence discriminatory actions. In this research, we introduce a novel tabular diffusion model that incorporates sensitive guidance to generate fair synthetic data with balanced joint distributions of the target label and sensitive attributes, such as sex and race. The empirical results demonstrate that our method effectively mitigates bias in training data while maintaining the quality of the generated samples. Furthermore, we provide evidence that our approach outperforms existing methods for synthesizing tabular data on fairness metrics such as demographic parity ratio and equalized odds ratio, achieving improvements of over 10%. Our implementation is available at https://github.com/comp-well-org/fair-tab-diffusion.</p>","PeriodicalId":75238,"journal":{"name":"Transactions on machine learning research","volume":"2025 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12975070/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147438335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yiheng He, Ruiyi Zhang, Sai Ashish Somayajula, Pengtao Xie
{"title":"Transformer Architecture Search for Improving Out-of-Domain Generalization in Machine Translation.","authors":"Yiheng He, Ruiyi Zhang, Sai Ashish Somayajula, Pengtao Xie","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Interest in automatically searching for Transformer neural architectures for machine translation (MT) has been increasing. Current methods show promising results in in-domain settings, where training and test data share the same distribution. However, in real-world MT applications, it is common that the test data has a different distribution than the training data. In these out-of-domain (OOD) situations, Transformer architectures optimized for the linguistic characteristics of the training sentences struggle to produce accurate translations for OOD sentences during testing. To tackle this issue, we propose a multi-level optimization based method to automatically search for neural architectures that possess robust OOD generalization capabilities. During the architecture search process, our method automatically synthesizes approximated OOD MT data, which is used to evaluate and improve the architectures' ability of generalizing to OOD scenarios. The generation of approximated OOD data and the search for optimal architectures are executed in an integrated, end-to-end manner. Evaluated across multiple datasets, our method demonstrates strong OOD generalization performance, surpassing state-of-the-art approaches. Our code is publicly available at https://github.com/yihenghe/transformer_nas.</p>","PeriodicalId":75238,"journal":{"name":"Transactions on machine learning research","volume":"2024 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12356094/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144877137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"AdaWaveNet: Adaptive Wavelet Network for Time Series Analysis.","authors":"Han Yu, Peikun Guo, Akane Sano","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Time series data analysis is a critical component in various domains such as finance, healthcare, and meteorology. Despite the progress in deep learning for time series analysis, there remains a challenge in addressing the non-stationary nature of time series data. Most of the existing models, which are built on the assumption of constant statistical properties over time, often struggle to capture the temporal dynamics in realistic time series and result in bias and error in time series analysis. This paper introduces the Adaptive Wavelet Network (<i>AdaWaveNet</i>), a novel approach that employs Adaptive Wavelet Transformation for multiscale analysis of non-stationary time series data. <i>AdaWaveNet</i> designed a lifting scheme-based wavelet decomposition and construction mechanism for adaptive and learnable wavelet transforms, which offers enhanced flexibility and robustness in analysis. We conduct extensive experiments on 10 datasets across 3 different tasks, including forecasting, imputation, and a newly established super-resolution task. The evaluations demonstrate the effectiveness of <i>AdaWaveNet</i> over existing methods in all three tasks, which illustrates its potential in various real-world applications. The code implemented for the <i>Ada WaveNet</i> is available at https://github.com/comp-well-org/AdaWaveNet.</p>","PeriodicalId":75238,"journal":{"name":"Transactions on machine learning research","volume":"2024 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12974719/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147438327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Selective Classification Under Distribution Shifts.","authors":"Hengyue Liang, Le Peng, Ju Sun","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In selective classification (SC), a classifier abstains from making predictions that are likely to be wrong to avoid excessive errors. To deploy imperfect classifiers-either due to intrinsic statistical noise of data or for robustness issue of the classifier or beyond-in high-stakes scenarios, SC appears to be an attractive and necessary path to follow. Despite decades of research in SC, most previous SC methods still focus on the ideal statistical setting only, i.e., the data distribution at deployment is the same as that of training, although practical data can come from the wild. To bridge this gap, in this paper, we propose an SC framework that takes into account distribution shifts, termed <i>generalized selective classification</i>, that covers label-shifted (or out-of-distribution) and covariate-shifted samples, in addition to typical in-distribution samples, <i>the first of its kind</i> in the SC literature. We focus on non-training-based confidence-score functions for generalized SC on deep learning (DL) classifiers, and propose two novel margin-based score functions. Through extensive analysis and experiments, we show that our proposed score functions are more effective and reliable than the existing ones for generalized SC on a variety of classification tasks and DL classifiers. The code is available at https://github.com/sun-umn/sc_with_distshift.</p>","PeriodicalId":75238,"journal":{"name":"Transactions on machine learning research","volume":"2024 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12470254/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145187750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"MoMA: Model-based Mirror Ascent for Offline Reinforcement Learning.","authors":"Mao Hong, Zhiyue Zhang, Yue Wu, Yanxun Xu","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Model-based offline reinforcement learning methods (RL) have achieved state-of-the-art performance in many decision-making problems thanks to their sample efficiency and generalizability. Despite these advancements, existing model-based offline RL approaches either focus on theoretical studies without developing practical algorithms or rely on a restricted parametric policy space, thus not fully leveraging the advantages of an unrestricted policy space inherent to model-based methods. To address this limitation, we develop MoMA, a model-based mirror ascent algorithm with general function approximations under partial coverage of offline data. MoMA distinguishes itself from existing literature by employing an unrestricted policy class. In each iteration, MoMA conservatively estimates the value function by a minimization procedure within a confidence set of transition models in the policy evaluation step, then updates the policy with general function approximations instead of commonly-used parametric policy classes in the policy improvement step. Under some mild assumptions, we establish theoretical guarantees for MoMA by proving an upper bound on the suboptimality of the returned policy. We also provide a practically implementable, approximate version of the algorithm. The effectiveness of MoMA is demonstrated via numerical studies.</p>","PeriodicalId":75238,"journal":{"name":"Transactions on machine learning research","volume":"2024 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12742664/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145851635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zahra Moslemi, Yang Meng, Shiwei Lan, Babak Shahbaba
{"title":"Scaling Up Bayesian Neural Networks with Neural Networks.","authors":"Zahra Moslemi, Yang Meng, Shiwei Lan, Babak Shahbaba","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Bayesian Neural Networks (BNNs) offer a principled and natural framework for proper uncertainty quantification in the context of deep learning. They address the typical challenges associated with conventional deep learning methods, such as data insatiability, ad-hoc nature, and susceptibility to overfitting. However, their implementation typically either relies on Markov chain Monte Carlo (MCMC) methods, which are characterized by their computational intensity and inefficiency in a high-dimensional space, or variational inference methods, which tend to underestimate uncertainty. To address this issue, we propose a novel Calibration-Emulation-Sampling (CES) strategy to significantly enhance the computational efficiency of BNN. In this framework, during the initial calibration stage, we collect a small set of samples from the parameter space. These samples serve as training data for the emulator, which approximates the map between parameters and posterior probability. The trained emulator is then used for sampling from the posterior distribution at substantially higher speed compared to the standard BNN. Using simulated and real data, we demonstrate that our proposed method improves computational efficiency of BNN, while maintaining similar performance in terms of prediction accuracy and uncertainty quantification.</p>","PeriodicalId":75238,"journal":{"name":"Transactions on machine learning research","volume":"2024 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13313050/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148355167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"ECG Semantic Integrator (ESI): A Foundation ECG Model Pretrained with LLM-Enhanced Cardiological Text.","authors":"Han Yu, Peikun Guo, Akane Sano","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The utilization of deep learning on electrocardiogram (ECG) analysis has brought the advanced accuracy and efficiency of cardiac healthcare diagnostics. In this work, we address a critical challenge in the field of ECG analysis with deep learning: learning robust representation without large-scale labeled datasets. We propose ECG Semantic Integrator (ESI), a novel multimodal contrastive pretraining framework that jointly learns from ECG signals and associated textual descriptions. ESI employs a dual objective function that comprises a contrastive loss and a captioning loss to develop representations of ECG data. To create a sufficiently large and diverse training dataset, we develop a retrieval-augmented generation (RAG)-based Large Language Model (LLM) pipeline, called Cardio Query Assistant (CQA). This pipeline is designed to generate detailed textual descriptions for ECGs from diverse databases. The generated text includes information about demographics and waveform patterns. This approach enables us to compile a large-scale multimodal dataset with over 660,000 ECG-text pairs for pretraining ESI, which then learns robust and generalizable representations of 12-lead ECG. We validate our approach through various downstream tasks, including arrhythmia detection and ECG-based subject identification. Our experimental results demonstrate substantial improvements over strong baselines in these tasks. These baselines encompass supervised and self-supervised learning methods, as well as prior multimodal pretraining approaches. Our work shows the potential of combining multimodal pretraining to improve the analysis of ECG signals. The training code and generated waveform descriptions are available at https://github.com/comp-well-org/ESI.</p>","PeriodicalId":75238,"journal":{"name":"Transactions on machine learning research","volume":"2024 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12974696/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147438299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Junjie Yin, Jiahao Dong, Yingheng Wang, Christopher De Sa, Volodymyr Kuleshov
{"title":"ModuLoRA: Finetuning 2-Bit LLMs on Consumer GPUs by Integrating with Modular Quantizers.","authors":"Junjie Yin, Jiahao Dong, Yingheng Wang, Christopher De Sa, Volodymyr Kuleshov","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We propose a memory-efficient finetuning algorithm for large language models (LLMs) that supports finetuning LLMs with 65B parameters in 2/3/4-bit precision on as little as one 24GB GPU. Our method, modular low-rank adaptation (ModuLoRA), integrates any user-specified weight quantizer with finetuning via low-rank adapters (LoRAs). Our approach relies on a simple quantization-agnostic backward pass that adaptively materializes low-precision LLM weights from a custom black-box quantization module. This approach enables finetuning 2-bit and 3-bit LLMs for the first time-leveraging state-of-the-art 2-bit QuIP# quantization and 3-bit OPTQ quantization-outperforming finetuning that relies on less sophisticated 4-bit and 8-bit methods. In our experiments, ModuLoRA attains competitive performance on text classification, natural language inference, and instruction following tasks using significantly less memory than existing approaches, and we also surpass the state-of-the-art ROUGE score on a popular summarization task. We release ModuLoRA together with a series of low-precision models as part of LLMTools, a user-friendly library for quantizing, running, and finetuning LLMs on consumer GPUs.</p>","PeriodicalId":75238,"journal":{"name":"Transactions on machine learning research","volume":"2024 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12362356/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144981971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}