手法を比較

	距離学習	オンライン学習
分野	機械学習	機械学習
系統	Machine learning	Machine learning
提唱年	2003 (foundational); refined 2009 (LMNN)	1958–2000s
提唱者	Xing, E. P.; Jordan, M. I.; Russell, S.; Ng, A. Y.	Rosenblatt, F.; Littlestone, N.; Shalev-Shwartz, S. (key contributors)
種類	Representation learning / supervised distance optimization	Learning paradigm (sequential model update)
原典	Xing, E. P., Jordan, M. I., Russell, S., & Ng, A. Y. (2003). Distance metric learning with application to clustering with side-information. In Advances in Neural Information Processing Systems (NIPS), 16, 505–512.	Shalev-Shwartz, S. (2011). Online Learning and Online Convex Optimization. Foundations and Trends in Machine Learning, 4(2), 107–194.
別名	Distance Metric Learning, Similarity Learning, DML, Representation Learning via Distance	incremental learning, sequential learning, streaming learning, online machine learning
関連	5	6
概要	Metric learning is a machine-learning framework that trains a distance or similarity function from data so that semantically similar examples end up close together in the learned space while dissimilar examples are pushed apart. Unlike fixed distances such as Euclidean, the learned metric adapts to the structure of the task, making downstream classifiers, clusterers, and retrieval systems significantly more accurate.	Online learning is a machine learning paradigm in which a model is updated incrementally as each new data point arrives, rather than being trained once on a fixed dataset. It is essential when data streams continuously, storage is limited, or the underlying distribution shifts over time. Theoretical performance is measured by cumulative regret relative to the best fixed predictor in hindsight.