deep learning is a subset of machine learning, and machine learning is a subset of artificial intelligence. https://www.coursera.org/articles/ai-vs-deep-learning-vs-machine-learning-beginners-guide
- Tom Mitchell 关于机器学习的定义被广泛引用，如下所示：
- 对于某类任务T和性能度量P，如果一个计算机程序在T上以P衡量的性能随着经验E而不断自我完善，那么我们称这个计算机程序在从经验E学习。
- “A computer program is said to learn from experience E with respect to some class of tasks T and performance measure P if its performance at tasks in T, as measured by P, improves with experience E ”
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深度学习是一种特殊的机器学习，它将现实世界表示为嵌套的层次概念体系（由较简单概念间的联系定义复杂概念，从一般抽象概括到高级抽象表示），从而获得强大的性能与灵活性。
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Deep learning is a particular kind of machine learning that achieves great power and flexibility by learning to represent the world as nested hierarchy of concepts, with each concept defined in relation to simpler concepts, and more abstract representations computed in terms of less abstract ones.