如何将神经网络转换为卷积神经网络？

Question

我正在使用 US-CERT 作为 TensorFlow 中的数据集进行内部威胁检测。

代码如下：

    import numpy as np
import pandas as pd
import tensorflow as tf
from tensorflow import feature_column
from tensorflow.keras import layers
from sklearn.model_selection import train_test_split
from pandas.api.types import CategoricalDtype

#Use Pandas to create a dataframe
#In windows to get file from path other than same run directory see:
#https://stackoverflow.com/questions/16952632/read-a-csv-into-pandas-from-f-drive-on-windows-7

URL = 'https://raw.githubusercontent.com/dc401/tensorflow-insiderthreat/master/scenario2-training-dataset-transformed-tf.csv'
dataframe = pd.read_csv(URL)
#print(dataframe.head())

#show dataframe details for column types
#print(dataframe.info())

#print(pd.unique(dataframe['user']))
#https://pbpython.com/categorical-encoding.html
dataframe["user"] = dataframe["user"].astype('category')
dataframe["source"] = dataframe["source"].astype('category')
dataframe["action"] = dataframe["action"].astype('category')
dataframe["user_cat"] = dataframe["user"].cat.codes
dataframe["source_cat"] = dataframe["source"].cat.codes
dataframe["action_cat"] = dataframe["action"].cat.codes

#print(dataframe.info())
#print(dataframe.head())

#save dataframe with new columns for future datmapping
dataframe.to_csv('dataframe-export-allcolumns.csv')

#remove old columns
del dataframe["user"]
del dataframe["source"]
del dataframe["action"]
#restore original names of columns
dataframe.rename(columns={"user_cat": "user", "source_cat": "source", "action_cat": "action"}, inplace=True)
print(dataframe.head())
print(dataframe.info())

#save dataframe cleaned up
dataframe.to_csv('dataframe-export-int-cleaned.csv')


#Split the dataframe into train, validation, and test
train, test = train_test_split(dataframe, test_size=0.2)
train, val = train_test_split(train, test_size=0.2)
print(len(train), 'train examples')
print(len(val), 'validation examples')
print(len(test), 'test examples')

#Create an input pipeline using tf.data
# A utility method to create a tf.data dataset from a Pandas Dataframe
def df_to_dataset(dataframe, shuffle=True, batch_size=32):
  dataframe = dataframe.copy()
  labels = dataframe.pop('insiderthreat')
  ds = tf.data.Dataset.from_tensor_slices((dict(dataframe), labels))
  if shuffle:
    ds = ds.shuffle(buffer_size=len(dataframe))
  ds = ds.batch(batch_size)
  return ds


#choose columns needed for calculations (features)
feature_columns = []
for header in ["vector", "date", "user", "source", "action"]:
    feature_columns.append(feature_column.numeric_column(header))

#create feature layer
feature_layer = tf.keras.layers.DenseFeatures(feature_columns)

#set batch size pipeline
batch_size = 32
train_ds = df_to_dataset(train, batch_size=batch_size)
val_ds = df_to_dataset(val, shuffle=False, batch_size=batch_size)
test_ds = df_to_dataset(test, shuffle=False, batch_size=batch_size)

#create compile and train model
model = tf.keras.Sequential([
  feature_layer,
  layers.Dense(128, activation='relu'),
  layers.Dense(128, activation='relu'),
  layers.Dense(1)
])

model.compile(optimizer='adam',
              loss=tf.keras.losses.BinaryCrossentropy(from_logits=True),
              metrics=['accuracy'])

model.fit(train_ds,
          validation_data=val_ds,
          epochs=5)

loss, accuracy = model.evaluate(test_ds)
print("Accuracy", accuracy)

准确率在 60% 到 50% 之间，所以我想将这个神经网络转换为卷积神经网络，以提高准确率。 我认为关键是在这里添加更多层，例如

#create compile and train model
model = tf.keras.Sequential([
  feature_layer,
  layers.Dense(128, activation='relu'),
  layers.Dense(128, activation='relu'),
  layers.Dense(1)
])

问题是如何将这个模型转化为卷积神经网络？

Answer 1

您只需将密集层替换为卷积和池化层：

#create compile and train model
model = tf.keras.Sequential([
    feature_layer,
    layers.Conv1D(*args),
    layers.MaxPooling1D(*args),
    layers.Flatten(),
    layers.Dense(1)
])

您可以使用the tensorflow documentation on CNNs 拼凑您应该使用哪些参数以及如何进一步自定义您的应用程序。

Answer 2

一个 CNN 包括：

• 卷积层
• 全连接层（具有密集层的典型神经网络）。

所以，一个简单的 CNN 的架构如下所示：

CNN 层展平后，您可以开始添加密集层，就像您在代码中所做的那样。

上图的CNN是这样的：

model = tf.keras.models.Sequential()
model.add(tf.keras.layers.Input(28,28,1))

# Adding Convolutional Layers here:
model.add(tf.keras.layers.Conv2D(filters=32, kernel_size=3, strides=1, activation='relu')
model.add(tf.keras.layers.Conv2D(filters=32, kernel_size=2, strides=2, activation='relu')
model.add(tf.keras.layers.Conv2D(filters=64, kernel_size=3, strides=1, activation='relu')
model.add(tf.keras.layers.Conv2D(filters=64, kernel_size=2, strides=2, activation='relu')

model.add(tf.keras.layers.Flatten())

# This is where you add the Fully-Connected layers.
model.add(tf.keras.layers.Dense(units=128, activation='relu'))
model.add(tf.keras.layers.Dense(units=10, activation='sigmoid'))

model.summary()

我发现了这个很棒的存储库，其中包含一个使用 tensorflow 创建简单、易于理解但功能强大的 CNN 的示例： https://github.com/kochlisGit/Tensorflow-State-of-the-Art-Neural-Networks/tree/master/MNIST-State-of-the-Art