Unsupervised or Indirectly Supervised Learning
A Median Perspective on Unlabeled Data for Out-of-Distribution Detection
Abbas, Momin, Falahati, Ali, Goli, Hossein, Amiri, Mohammad Mohammadi
Out-of-distribution (OOD) detection plays a crucial role in ensuring the robustness and reliability of machine learning systems deployed in real-world applications. Recent approaches have explored the use of unlabeled data, showing potential for enhancing OOD detection capabilities. However, effectively utilizing unlabeled in-the-wild data remains challenging due to the mixed nature of both in-distribution (InD) and OOD samples. The lack of a distinct set of OOD samples complicates the task of training an optimal OOD classifier. In this work, we introduce Medix, a novel framework designed to identify potential outliers from unlabeled data using the median operation. We use the median because it provides a stable estimate of the central tendency, as an OOD detection mechanism, due to its robustness against noise and outliers. Using these identified outliers, along with labeled InD data, we train a robust OOD classifier. From a theoretical perspective, we derive error bounds that demonstrate Medix achieves a low error rate. Empirical results further substantiate our claims, as Medix outperforms existing methods across the board in open-world settings, confirming the validity of our theoretical insights.
Better Semi-supervised Learning for Multi-domain ASR Through Incremental Retraining and Data Filtering
Carofilis, Andres, Rangappa, Pradeep, Madikeri, Srikanth, Kumar, Shashi, Burdisso, Sergio, Prakash, Jeena, Villatoro-Tello, Esau, Motlicek, Petr, Sharma, Bidisha, Hacioglu, Kadri, Venkatesan, Shankar, Vyas, Saurabh, Stolcke, Andreas
Fine-tuning pretrained ASR models for specific domains is challenging when labeled data is scarce. But unlabeled audio and labeled data from related domains are often available. We propose an incremental semi-supervised learning pipeline that first integrates a small in-domain labeled set and an auxiliary dataset from a closely related domain, achieving a relative improvement of 4% over no auxiliary data. Filtering based on multi-model consensus or named entity recognition (NER) is then applied to select and iteratively refine pseudo-labels, showing slower performance saturation compared to random selection. Evaluated on the multi-domain Wow call center and Fisher English corpora, it outperforms single-step fine-tuning. Consensus-based filtering outperforms other methods, providing up to 22.3% relative improvement on Wow and 24.8% on Fisher over single-step fine-tuning with random selection. NER is the second-best filter, providing competitive performance at a lower computational cost.
CSG: Unsupervised Learning of Compact CSG Trees with Dual Complements and Dropouts Fenggen Y u
CSG and CAPRI-Net mentioned in Section 3 of the main paper. To prove Proposition 1, we provide an example that CAPRI-Net's sequence fails to support. CSG is able to support any CSG sequence. Each sub-figure represents a 2D implicit filed defined by the notation below. Specifically, we obtain the mesh for each primitive by performing Marching-Cube on the signed distance field produced by the quadric equation of that primitive.
New Recipe for Semi-supervised Community Detection: Clique Annealing under Crystallization Kinetics
Cheng, Ling, Pu, Jiashu, Liang, Ruicheng, Shao, Qian, Qiao, Hezhe, Zhu, Feida
Semi-supervised community detection methods are widely used for identifying specific communities due to the label scarcity. Existing semi-supervised community detection methods typically involve two learning stages learning in both initial identification and subsequent adjustment, which often starts from an unreasonable community core candidate. Moreover, these methods encounter scalability issues because they depend on reinforcement learning and generative adversarial networks, leading to higher computational costs and restricting the selection of candidates. To address these limitations, we draw a parallel between crystallization kinetics and community detection to integrate the spontaneity of the annealing process into community detection. Specifically, we liken community detection to identifying a crystal subgrain (core) that expands into a complete grain (community) through a process similar to annealing. Based on this finding, we propose CLique ANNealing (CLANN), which applies kinetics concepts to community detection by integrating these principles into the optimization process to strengthen the consistency of the community core. Subsequently, a learning-free Transitive Annealer was employed to refine the first-stage candidates by merging neighboring cliques and repositioning the community core, enabling a spontaneous growth process that enhances scalability. Extensive experiments on \textbf{43} different network settings demonstrate that CLANN outperforms state-of-the-art methods across multiple real-world datasets, showcasing its exceptional efficacy and efficiency in community detection.