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1. Neural Bootstrapper

   Shin, M.; Cho, H.; Min, H-S.; Lim, S. (January 2021, Advances in neural information processing systems)

   Ranzato, M.; Beygelzimer, A.; Dauphin, Y.; Liang, P. S.; Wortman Vaughan, J. (Ed.)

   Bootstrapping has been a primary tool for ensemble and uncertainty quantification in machine learning and statistics. However, due to its nature of multiple training and resampling, bootstrapping deep neural networks is computationally burdensome; hence it has difficulties in practical application to the uncertainty estimation and related tasks. To overcome this computational bottleneck, we propose a novel approach called Neural Bootstrapper (NeuBoots), which learns to generate bootstrapped neural networks through single model training. NeuBoots injects the bootstrap weights into the high-level feature layers of the backbone network and outputs the bootstrapped predictions of the target, without additional parameters and the repetitive computations from scratch. We apply NeuBoots to various machine learning tasks related to uncertainty quantification, including prediction calibrations in image classification and semantic segmentation, active learning, and detection of out-of-distribution samples. Our empirical results show that NeuBoots outperforms other bagging based methods under a much lower computational cost without losing the validity of bootstrapping. 

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2. A Semi-Supervised and Inductive Embedding Model for Churn Prediction of Large-Scale Mobile Games

   https://doi.org/10.1109/ICDM.2018.00043  

   Liu, Xi; Xie, Muhe; Wen, Xidao; Chen, Rui; Ge, Yong; Duffield, Nick; Wang, Na (November 2018, 2018 IEEE International Conference on Data Mining (ICDM 2018))

   Mobile gaming has emerged as a promising market with billion-dollar revenues. A variety of mobile game platforms and services have been developed around the world. One critical challenge for these platforms and services is to understand user churn behavior in mobile games. Accurate churn prediction will bene t many stakeholders such as game developers, advertisers, and platform operators. In this paper, we present the rst large- scale churn prediction solution for mobile games. In view of the common limitations of the state-of-the-art methods built upon traditional machine learning models, we devise a novel semi- supervised and inductive embedding model that jointly learns the prediction function and the embedding function for user- app relationships. We model these two functions by deep neural networks with a unique edge embedding technique that is able to capture both contextual information and relationship dynamics. We also design a novel attributed random walk technique that takes into consideration both topological adjacency and attribute similarities. To evaluate the performance of our solution, we collect real-world data from the Samsung Game Launcher platform that includes tens of thousands of games and hundreds of millions of user-app interactions. The experimental results with this data demonstrate the superiority of our proposed model against existing state-of-the-art methods. 

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3. An empirical study of using radiology reports and images to improve ICU-mortality prediction

   https://doi.org/10.1109/ichi52183.2021.00088  

   Lin, Mingquan; Wang, Song; Ding, Ying; Zhao, Lihui; Wang, Fei; Peng, Yifan (August 2021, IEEE)

   The predictive Intensive Care Unit (ICU) scoring system plays an important role in ICU management for its capability of predicting important outcomes, especially mortality. There are many scoring systems that have been developed and used in the ICU. These scoring systems are primarily based on the structured clinical data contained in the electronic health record (EHR), which may suffer the loss of the important clinical information contained in the narratives and images. In this work, we build a deep learning based survival prediction model with multimodality data to predict ICU-mortality. Four sets of features are investigated: (1) physiological measurements of Simplified Acute Physiology Score (SAPS) II, (2) common thorax diseases predefined by radiologists, (3) BERT-based text representations, and (4) chest X-ray image features. We use the Medical Information Mart for Intensive Care IV (MIMIC-IV) dataset to evaluate the proposed model. Our model achieves the average C-index of 0.7847 (95% confidence interval, 0.7625–0.8068), which substantially exceeds that of the baseline with SAPS-II features (0.7477 (0.7238–0.7716)). Ablation studies further demonstrate the contributions of pre-defined labels (2.12%), text features (2.68%), and image features (2.96%). Our model achieves a higher average C-index than the traditional machine learning methods under the same feature fusion setting, which suggests that the deep learning methods can outperform the traditional machine learning methods in ICU-mortality prediction. These results highlight the potential of deep learning models with multimodal information to enhance ICU-mortality prediction. We make our work publicly available at https://github.com/bionlplab/mimic-icu-mortality. 

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4. Time series predictions in unmonitored sites: a survey of machine learning techniques in water resources

   https://doi.org/10.1017/eds.2024.14  

   Willard, Jared D; Varadharajan, Charuleka; Jia, Xiaowei; Kumar, Vipin (January 2025, Environmental Data Science)

   Abstract Prediction of dynamic environmental variables in unmonitored sites remains a long-standing challenge for water resources science. The majority of the world’s freshwater resources have inadequate monitoring of critical environmental variables needed for management. Yet, the need to have widespread predictions of hydrological variables such as river flow and water quality has become increasingly urgent due to climate and land use change over the past decades, and their associated impacts on water resources. Modern machine learning methods increasingly outperform their process-based and empirical model counterparts for hydrologic time series prediction with their ability to extract information from large, diverse data sets. We review relevant state-of-the art applications of machine learning for streamflow, water quality, and other water resources prediction and discuss opportunities to improve the use of machine learning with emerging methods for incorporating watershed characteristics and process knowledge into classical, deep learning, and transfer learning methodologies. The analysis here suggests most prior efforts have been focused on deep learning frameworks built on many sites for predictions at daily time scales in the United States, but that comparisons between different classes of machine learning methods are few and inadequate. We identify several open questions for time series predictions in unmonitored sites that include incorporating dynamic inputs and site characteristics, mechanistic understanding and spatial context, and explainable AI techniques in modern machine learning frameworks. 

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5. Application of Convolutional Neural Network Algorithms for Advancing Sedentary and Activity Bout Classification

   https://doi.org/10.1123/jmpb.2020-0016  

   Nakandala, Supun; Jankowska, Marta M.; Tuz-Zahra, Fatima; Bellettiere, John; Carlson, Jordan A.; LaCroix, Andrea Z.; Hartman, Sheri J.; Rosenberg, Dori E.; Zou, Jingjing; Kumar, Arun; et al (January 2020, Journal for the Measurement of Physical Behaviour)

   null (Ed.)

   Background : Machine learning has been used for classification of physical behavior bouts from hip-worn accelerometers; however, this research has been limited due to the challenges of directly observing and coding human behavior “in the wild.” Deep learning algorithms, such as convolutional neural networks (CNNs), may offer better representation of data than other machine learning algorithms without the need for engineered features and may be better suited to dealing with free-living data. The purpose of this study was to develop a modeling pipeline for evaluation of a CNN model on a free-living data set and compare CNN inputs and results with the commonly used machine learning random forest and logistic regression algorithms. Method : Twenty-eight free-living women wore an ActiGraph GT3X+ accelerometer on their right hip for 7 days. A concurrently worn thigh-mounted activPAL device captured ground truth activity labels. The authors evaluated logistic regression, random forest, and CNN models for classifying sitting, standing, and stepping bouts. The authors also assessed the benefit of performing feature engineering for this task. Results : The CNN classifier performed best (average balanced accuracy for bout classification of sitting, standing, and stepping was 84%) compared with the other methods (56% for logistic regression and 76% for random forest), even without performing any feature engineering. Conclusion : Using the recent advancements in deep neural networks, the authors showed that a CNN model can outperform other methods even without feature engineering. This has important implications for both the model’s ability to deal with the complexity of free-living data and its potential transferability to new populations. 

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