TensorFlow & Keras

Some Machine Learning terminology

特征，Feature — The input(s) to our model. In this case, a single value — the degrees in Celsius.

标签，Labels — The output our model predicts. In this case, a single value — the degrees in Fahrenheit.

样本，Example — A pair of inputs/outputs used during training. In our case a pair of values from celsius_q and fahrenheit_a at a specific index, such as (22,72).

Dense Layer，密集层

1. connect everything with everything

Fashion MNIIST Dataset

激活函数 ReLU（Rectified Linear Unit）

gives an output of 0 if the input is negative or zero, and if input is positive, then the output will be equal to the input.

其他激活函数还有 Sigmoid、tanh、ELU

CNN

Convolution neural network

1. convolution,

kernel 矩阵（Filter）

每个像素值取核矩阵大小的矩阵，计算与核矩阵的叉乘

1. maxpooling 最大池化

pool size stride

reduce the size of input image

Overfitting

过少参数，出现偏差 过多参数，overfitting

90% work is cleaning up data

图像增强（Image Augmentation），用各种随机图像转换创建新的训练样本 Dropout，训练中随机关闭某些神经元

迁移学习(transfer learning)

用大型数据集训练过的网络（预训练网络）应用在之前未结果的数据集上。

需要更改 output layer。

hiden layer 的变量不会被训练，称为冻结网络。

MobileNet

移动设备用。