Coursera Week 1 - Machine Learning Introduction
Machine-learning, Grew out of work in Artificial Intelligence, New capability for computers
Machine Learning
- Grew out of work in Artificial Intelligence
- New capability for computers
search engine, recommendation system, image recognition
web click data, medical records , biology, engineering
Natural Language Processing (NLP), Computer Vision
Machine Learning definition
Field of study that gives computers the ability to learn without being explicitly programmed. by ArthurSamuel(1959)
1. Supervised learning
2. Regression & Classification
3. Unsupervised learning
Unsupervised Examples
What Google News does is everyday it goes and looks at tens of thousands or hundreds of thousands of new stories on the web and it groups them into cohesive news stories.
4. Experience
Xiaoyang 语录 :
『解决一个问题的方法和思路不止一种』
『没有所谓的机器学习算法优劣，也没有绝对高性能的机器学习算法，只有在特定的场景、数据和特征下更合适的机器学习算法。』
Andrew Ng 语录
应用机器学习，不要一上来就试图做到完美，先lu一个baseline的model出来，再进行后续的分析步骤，一步步提高，所谓后续步骤可能包括『分析model现在的状态(欠/过拟合)，分析我们使用的feature的作用大小，进行feature selection，以及我们模型下的bad case和产生的原因』等等。
Kaggle大神们 experience 总结 ：
- 『对数据的认识太重要了！』
- 『数据中的特殊点/离群点的分析和处理太重要了！』
- 『特征工程(feature engineering)太重要了！在很多Kaggle的场景下，甚至比model本身还要重要』
- 『要做模型融合(model ensemble)啊啊啊！』
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