Questions and Answers
What is the purpose of the compile()
method in Keras?
To configure the learning process of the model
What is the purpose of the softmax
activation function in the output layer of a neural network?
To convert the output values into probabilities
What is the purpose of the hidden layers in a Multilayer Perceptron (MLP) architecture?
To introduce non-linearity into the model
What is the purpose of the model.summary()
method in Keras?
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What is the purpose of the input layer in a Multilayer Perceptron (MLP) architecture?
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What is the purpose of the output layer in a neural network?
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What is the role of the softmax function in neural networks?
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Which of the following is a common technique to prevent overfitting in neural networks?
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What is the purpose of the model.summary()
function in Keras?
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Which of the following is a common type of neural network architecture?
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What is the purpose of the output layer in a neural network?
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What is the role of the softmax function in the output layer of a neural network?
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How can you determine the optimal number of layers and nodes in a neural network architecture?
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What information is typically included in a neural network model summary?
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What is the primary purpose of having multiple hidden layers in a deep neural network?
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What is the recommended activation function to use in the hidden layers of a neural network?
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In a classification problem with 10 classes, how many nodes should be in the output layer of the neural network?
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What is the purpose of the softmax function in the output layer of a neural network for classification problems?
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What is the purpose of adding two fully connected (dense) layers to a neural network model?
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Which of the following is NOT a part of the neural network architecture shown in the image?
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What is the purpose of the softmax activation function in the output layer of a neural network?
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In the given code example, what is the purpose of the units
parameter in the Dense
layer?
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What is the purpose of the Sequential
model in Keras?
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What is the purpose of the model.add()
method in Keras?
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What is the purpose of the model.summary()
method in Keras (not shown in the given code)?
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What is the purpose of the Flatten layer in the neural network architecture?
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What is the role of the softmax activation function in the output layer of the neural network?
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How many trainable parameters are in the first hidden layer of the neural network?
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What is the purpose of the model.summary() function in the code?
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What is the purpose of the Dense layers in the neural network architecture?
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What is the purpose of the Flatten layer in a neural network?
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What is the input shape parameter supplied to the Flatten layer in the given code example?
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What is the purpose of the Sequential model in Keras?
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What is the role of the output layer in a neural network?
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What is the purpose of the softmax function in the output layer of a neural network for classification tasks?
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What is the purpose of the model.summary() function in Keras?
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What is the role of the hidden layers in a neural network?
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What is the purpose of the input_shape parameter in the Flatten layer?
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What is the purpose of the Sequential model in Keras?
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What is the role of the activation function in the output layer of a neural network for regression tasks?
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Study Notes
Keras Modules and Classes
- Keras has several modules:
- activations module: Built-in activation functions
- applications module: Keras Applications are premade architectures with pre-trained weights
- backend module: Keras backend API
- callbacks module: Callbacks: utilities called at certain points during model training
- constraints module: Constraints: functions that impose constraints on weight values
- datasets module: Small NumPy datasets for debugging/testing
- dtensor module: Keras' DTensor library
- estimator module: Keras estimator API
- experimental module: Public API for tf.keras.experimental namespace
- initializers module: Keras initializer serialization / deserialization
- layers module: Keras layers API
- losses module: Built-in loss functions
- metrics module: All Keras metrics
- mixed_precision module: Keras mixed precision API
- models module: Keras models API
- optimizers module: Built-in optimizer classes
- preprocessing module: Utilities to preprocess data before training
- regularizers module: Built-in regularizers
- utils module: Public Keras utilities
Keras Classes and Functions
- Class Model: Model groups layers into an object with training and inference features
- Class Sequential: Sequential groups a linear stack of layers into a tf.keras.Model
- Function Input(...): Input() is used to instantiate a Keras tensor
Building a Neural Network
- The core data structures of Keras are layers and models
- The simplest type of model is the Sequential model, a linear stack of layers
- For more complex architectures, use the Keras functional API or write models entirely from scratch via subclassing
Building a Neural Network (continued)
- When building a network, choose:
- The number of layers (e.g., 2)
- The size of each layer (e.g., 512, 32)
- The activation function of each layer (e.g., ReLU and ReLU)
Hidden Layers
- Add fully connected (dense) layers using Keras:
- Import the Dense layer from keras
- Use the Dense layer to add hidden layers (e.g., 2 layers with 512 and 32 nodes)
Output Layer
- In classification problems, the number of nodes in the output layer should be equal to the number of classes (e.g., 10 nodes for 10 classes)
- Use the softmax activation function in the output layer for classification problems
Putting it all Together
- Build a neural network by stacking layers together
- Use the Flatten layer to convert the image matrix into a vector
- Add hidden layers and an output layer with the chosen activation functions and number of nodes
- Compile the model with a chosen loss function and optimizer
- Train the model using the fit method
- Evaluate the model using the evaluate method