Neural Network Motivations 想要拟合一条曲线,在feature 很多的情况下,feature的组合也很多,在现实中不适用,比如在computer vision问题中feature就太多了. Applications cost function and BP                 Gradient Checking https://www.coursera.org/learn/machine-learning/supplement/pjdBA/backpropa…

Andrew NG的Machine learning课程地址为:https://www.coursera.org/course/ml 神经网络一直被认为是比较难懂的问题,NG将神经网络部分的课程分为了两个星期来介绍,可见Neural Networks内容之多.言归正传,通过之前的学习我们知道,使用非线性的多项式能够帮助我们建立更好的分类模型.但当遇特征非常多的时候,需要训练的参数太多,使得训练非常复杂,使得逻辑回归有心无力. 例如我们有100个特征,如果用这100个特征来构建一个非线性的多项式模…

Neural networks is a model inspired by how the brain works. It is widely used today in many applications: when your phone interprets(解释口译) and understand your voice commands, it is likely that a neural network is helping to understand your speech; wh…

Coursera课程<Neural Networks and Deep Learning> deeplearning.ai Week2 Neural Networks Basics 2.1 Logistic Regression as a Neutral Network 2.1.1 Binary Classification 二分类 逻辑回归是一个用于二分类(binary classification)的算法.首先我们从一个问题开始说起,这里有一个二分类问题的例子,假如你有一张图片作为输入,比…

Coursera课程<Neural Networks and Deep Learning> deeplearning.ai Week1 Introduction to deep learning What is a Neural Network? 让我们从一个房价预测的例子开始讲起. 假设你有一个数据集,它包含了六栋房子的信息.所以,你知道房屋的面积是多少平方英尺或者平方米,并且知道房屋价格.这时,你想要拟合一个根据房屋面积预测房价的函数. 如果使用线性回归进行拟合,那么可以拟合出一条直线.但…

Ensemble Methods for Deep Learning Neural Networks to Reduce Variance and Improve Performance 2018-12-19 13:02:45 This blog is copied from: https://machinelearningmastery.com/ensemble-methods-for-deep-learning-neural-networks/ Deep learning neural ne…

本文主要参考Ensemble Methods for Deep Learning Neural Networks一文. 1. 前言 神经网络具有很高的方差,不易复现出结果,而且模型的结果对初始化参数异常敏感. 使用集成模型可以有效降低神经网络的高方差(variance). 2. 使用集成模型降低方差 训练多个模型,并将预测结果结合到一起,能够降低方差. 多模型集成能起到作用的前提是,每个模型有自己的特点,每个模型预测出的误差是不同的. 简单的集成方式就是将预测结果取平均,该方法起作用的原因是,不…

原文 http://blog.csdn.net/abcjennifer/article/details/7749309 本栏目(Machine learning)包括单参数的线性回归.多参数的线性回归.Octave Tutorial.Logistic Regression.Regularization.神经网络.机器学习系统设计.SVM(Support Vector Machines 支持向量机).聚类.降维.异常检测.大规模机器学习等章节.所有内容均来自Standford公开课machine…

  Basic theory (i) Supervised learning (parametric/non-parametric algorithms, support vector machines, kernels, neural networks, )  regression, classification. (ii) Unsupervised learning (clustering, dimensionality reduction, recommender systems, dee…

https://www.coursera.org/learn/machine-learning/exam/7pytE/linear-regression-with-multiple-variables 1. Suppose m=4 students have taken some class, and the class had a midterm exam and a final exam. You have collected a dataset of their scores on the…