Step 6: Robust Neural Networks and Deep Learning

This blog will teach you how to build robust neural networks and use deep learning techniques to handle complex data such as images, text, and audio.

Table of Contents

1. Introduction

In this blog, you will learn how to build robust neural networks and use deep learning techniques to handle complex data such as images, text, and audio. Neural networks are powerful computational models that can learn from data and perform various tasks such as classification, regression, and generation. However, neural networks are also prone to errors and failures when faced with noisy, incomplete, or adversarial data. How can you make your neural networks more robust and reliable?

One way is to use deep learning, which is a branch of machine learning that deals with deep neural networks. Deep neural networks have multiple layers of neurons that can extract high-level features from raw data and learn complex patterns and representations. Deep learning has achieved remarkable results in many domains such as computer vision, natural language processing, and speech recognition. However, deep learning also comes with its own challenges and limitations, such as overfitting, generalization, and interpretability. How can you use deep learning effectively and efficiently for your data?

In this blog, you will explore some of the concepts and techniques that can help you answer these questions. You will learn about:

What are robust neural networks and why they are important
What are the main challenges and solutions for building robust neural networks
How to use deep learning for complex data such as images, text, and audio
What are convolutional neural networks and recurrent neural networks and how they work
How to prevent overfitting and improve generalization using dropout and other regularization techniques

By the end of this blog, you will have a better understanding of how to build robust neural networks and use deep learning for your data. You will also be able to apply some of the techniques and tools that are available for implementing and testing your neural networks. Ready to get started? Let’s dive in!

2. What are Robust Neural Networks?

A robust neural network is a neural network that can perform well under various conditions and scenarios, such as noise, uncertainty, incompleteness, or adversarial attacks. A robust neural network can adapt to changes in the data distribution, handle outliers and errors, and resist manipulation and deception. A robust neural network can also provide reliable and interpretable outputs, as well as confidence estimates and error bounds.

Why are robust neural networks important? Because real-world data is often noisy, incomplete, or adversarial, and neural networks need to cope with these challenges to provide accurate and trustworthy results. For example, imagine you are building a neural network to classify images of animals. You want your neural network to be able to recognize different types of animals, even if the images are blurry, cropped, or distorted. You also want your neural network to be able to reject images that are not animals, such as cars or buildings. And you definitely don’t want your neural network to be fooled by images that are intentionally modified to trick it, such as adding glasses or hats to animals.

How can you build robust neural networks? There is no single answer to this question, as different types of robustness may require different techniques and approaches. However, some of the general strategies that can help you improve the robustness of your neural networks are:

Using appropriate data preprocessing and augmentation techniques to reduce noise and increase diversity
Using appropriate network architectures and hyperparameters to balance complexity and simplicity
Using appropriate loss functions and optimization methods to minimize errors and maximize margins
Using appropriate regularization and normalization techniques to prevent overfitting and improve generalization
Using appropriate evaluation and validation methods to measure and monitor robustness
Using appropriate defense and mitigation techniques to detect and counter adversarial attacks

In the next sections, you will learn more about some of these techniques and how they can help you build robust neural networks.

2.1. Definition and Motivation

In this section, you will learn what robust neural networks are and why they are important for real-world applications. You will also learn some of the key concepts and terms related to robustness in neural networks.

Some of the key concepts and terms related to robustness in neural networks are:

Noise: Noise is any unwanted or random variation in the data that can affect the performance of the neural network. Noise can be present in the input data, such as pixel values, or in the output data, such as labels. Noise can also be present in the network itself, such as weights or activations.
Uncertainty: Uncertainty is the lack of complete or precise knowledge about the data or the model. Uncertainty can be due to noise, incompleteness, ambiguity, or variability. Uncertainty can be classified into two types: aleatoric uncertainty, which is inherent in the data and cannot be reduced, and epistemic uncertainty, which is due to the model and can be reduced with more data or better training.
Incompleteness: Incompleteness is the absence of some information or data that is relevant for the task. Incompleteness can be due to missing values, occlusions, or censoring. Incompleteness can affect the quality and quantity of the data available for training and testing the neural network.
Adversarial attacks: Adversarial attacks are deliberate and malicious attempts to fool or degrade the performance of the neural network. Adversarial attacks can be performed by modifying the input data, such as adding small perturbations to the images, or by modifying the network itself, such as changing the weights or activations. Adversarial attacks can be classified into two types: white-box attacks, where the attacker has full access to the network and its parameters, and black-box attacks, where the attacker has limited or no access to the network and its parameters.

As you can see, robustness is a complex and multifaceted concept that involves many aspects and challenges. In the next section, you will learn some of the main challenges and solutions for building robust neural networks.

2.2. Challenges and Solutions

In this section, you will learn some of the main challenges and solutions for building robust neural networks. You will see how different types of noise, uncertainty, incompleteness, and adversarial attacks can affect the performance and reliability of your neural networks. You will also see how different techniques and approaches can help you overcome these challenges and improve the robustness of your neural networks.

One of the main challenges for building robust neural networks is dealing with noise. Noise is any unwanted or random variation in the data that can affect the performance of the neural network. Noise can be present in the input data, such as pixel values, or in the output data, such as labels. Noise can also be present in the network itself, such as weights or activations. Noise can cause errors, inaccuracies, and inconsistencies in the neural network’s outputs, and reduce its confidence and interpretability.

One of the main solutions for dealing with noise is using data preprocessing and augmentation. Data preprocessing and augmentation are techniques that aim to reduce noise and increase diversity in the data. Data preprocessing involves cleaning, filtering, normalizing, and transforming the data to make it more suitable for the neural network. Data augmentation involves creating new or modified data from the existing data to increase the size and variety of the data. Data preprocessing and augmentation can help the neural network learn from more and better data, and improve its accuracy and robustness.

Another challenge for building robust neural networks is dealing with uncertainty. Uncertainty is the lack of complete or precise knowledge about the data or the model. Uncertainty can be due to noise, incompleteness, ambiguity, or variability. Uncertainty can affect the quality and quantity of the data available for training and testing the neural network. Uncertainty can also affect the confidence and reliability of the neural network’s outputs, and make it difficult to evaluate and validate its performance.

Another solution for dealing with uncertainty is using uncertainty estimation and quantification. Uncertainty estimation and quantification are techniques that aim to measure and express the uncertainty associated with the data or the model. Uncertainty estimation involves calculating the uncertainty of the neural network’s outputs, such as the probability or the variance. Uncertainty quantification involves providing the uncertainty of the neural network’s outputs, such as the confidence interval or the error bound. Uncertainty estimation and quantification can help the neural network provide more informative and trustworthy outputs, and improve its robustness and reliability.

A third challenge for building robust neural networks is dealing with incompleteness. Incompleteness is the absence of some information or data that is relevant for the task. Incompleteness can be due to missing values, occlusions, or censoring. Incompleteness can affect the quality and quantity of the data available for training and testing the neural network. Incompleteness can also affect the accuracy and completeness of the neural network’s outputs, and make it difficult to perform the task.

A third solution for dealing with incompleteness is using data imputation and completion. Data imputation and completion are techniques that aim to fill in or generate the missing or incomplete data. Data imputation involves estimating the missing or incomplete data from the available data, such as using the mean or the median. Data completion involves generating the missing or incomplete data from the model, such as using generative models or autoencoders. Data imputation and completion can help the neural network use more and complete data, and improve its accuracy and robustness.

A fourth challenge for building robust neural networks is dealing with adversarial attacks. Adversarial attacks are deliberate and malicious attempts to fool or degrade the performance of the neural network. Adversarial attacks can be performed by modifying the input data, such as adding small perturbations to the images, or by modifying the network itself, such as changing the weights or activations. Adversarial attacks can cause the neural network to produce wrong or misleading outputs, and compromise its security and integrity.

A fourth solution for dealing with adversarial attacks is using defense and mitigation. Defense and mitigation are techniques that aim to detect and counter adversarial attacks. Defense involves preventing or resisting adversarial attacks, such as using adversarial training or gradient masking. Mitigation involves correcting or recovering from adversarial attacks, such as using detection or correction methods. Defense and mitigation can help the neural network protect and restore its performance and robustness.

As you can see, building robust neural networks is not an easy task, as it involves many challenges and solutions. However, by using some of the techniques and approaches that we have discussed, you can improve the robustness of your neural networks and make them more reliable and trustworthy for your applications. In the next section, you will learn how to use deep learning for complex data such as images, text, and audio.

3. How to Use Deep Learning for Complex Data?

In this section, you will learn how to use deep learning for complex data such as images, text, and audio. You will see how deep learning can help you handle high-dimensional, heterogeneous, and sequential data, and perform tasks such as classification, generation, and translation. You will also see how deep learning can help you improve the robustness of your neural networks by extracting high-level features and learning complex patterns and representations.

What is deep learning? Deep learning is a branch of machine learning that deals with deep neural networks. Deep neural networks are neural networks that have multiple layers of neurons that can process and transform the data from one layer to another. Deep neural networks can learn from large amounts of data and perform various tasks such as classification, regression, and generation. Deep neural networks can also learn complex patterns and representations from raw data, such as images, text, and audio, without requiring much feature engineering or domain knowledge.

Why use deep learning for complex data? Because complex data is often high-dimensional, heterogeneous, and sequential, and requires advanced techniques and models to handle it. For example, imagine you are building a neural network to classify images of animals. You need to deal with images that have millions of pixels, different colors, shapes, and orientations, and different types of animals. You also need to deal with images that are noisy, incomplete, or adversarial. How can you handle such complex data?

One way is to use deep learning, which can help you handle complex data by using convolutional neural networks and recurrent neural networks. Convolutional neural networks are deep neural networks that use convolutional layers to extract local features from images, such as edges, shapes, and textures. Recurrent neural networks are deep neural networks that use recurrent layers to process sequential data, such as text, audio, and video. Convolutional neural networks and recurrent neural networks can help you handle complex data by reducing the dimensionality, capturing the heterogeneity, and modeling the sequentiality of the data. They can also help you improve the robustness of your neural networks by learning high-level features and representations that are invariant to noise, incompleteness, and adversarial attacks.

In the next sections, you will learn more about convolutional neural networks and recurrent neural networks and how they work. You will also learn how to use them for different tasks and applications involving complex data.

3.1. Convolutional Neural Networks

In this section, you will learn how to use convolutional neural networks for complex data such as images. You will see how convolutional neural networks can help you extract local features from images, such as edges, shapes, and textures. You will also see how convolutional neural networks can help you improve the robustness of your neural networks by learning high-level features and representations that are invariant to noise, incompleteness, and adversarial attacks.

What are convolutional neural networks? Convolutional neural networks are deep neural networks that use convolutional layers to process and transform the data from one layer to another. Convolutional layers are composed of multiple filters that slide over the input data and produce an output called a feature map. Each filter acts as a detector of a specific feature, such as an edge, a shape, or a texture. Each feature map represents the presence and location of that feature in the input data. By stacking multiple convolutional layers, the neural network can learn to extract more and more complex features from the data, such as faces, objects, or scenes.

Why use convolutional neural networks for complex data? Because complex data such as images is often high-dimensional, heterogeneous, and sequential, and requires advanced techniques and models to handle it. For example, imagine you are building a neural network to classify images of animals. You need to deal with images that have millions of pixels, different colors, shapes, and orientations, and different types of animals. You also need to deal with images that are noisy, incomplete, or adversarial. How can you handle such complex data?

One way is to use convolutional neural networks, which can help you handle complex data by reducing the dimensionality, capturing the heterogeneity, and modeling the sequentiality of the data. By using convolutional layers, you can reduce the dimensionality of the data by applying filters that extract only the relevant features from the data, and discard the irrelevant ones. By using multiple filters, you can capture the heterogeneity of the data by detecting different features that correspond to different aspects of the data, such as color, shape, or orientation. By using sequential filters, you can model the sequentiality of the data by learning the spatial relationships and dependencies between the features, such as the arrangement and composition of the features.

By using convolutional neural networks, you can also improve the robustness of your neural networks by learning high-level features and representations that are invariant to noise, incompleteness, and adversarial attacks. By using convolutional layers, you can learn features that are invariant to noise by applying filters that smooth out or remove the noise from the data, and enhance the signal. By using convolutional layers, you can learn features that are invariant to incompleteness by applying filters that fill in or generate the missing or incomplete data, and complete the image. By using convolutional layers, you can learn features that are invariant to adversarial attacks by applying filters that ignore or reject the perturbations or modifications that are added to the data, and restore the original image.

In the next section, you will learn how to use recurrent neural networks for complex data such as text and audio.

3.2. Recurrent Neural Networks

Another type of deep neural network that can handle complex data is a recurrent neural network (RNN). RNNs are designed to process sequential data, such as text, audio, or time series. RNNs can capture the temporal dependencies and patterns in the data, and generate outputs that depend on the previous inputs and states. RNNs are widely used for tasks such as natural language processing, speech recognition, and machine translation.

How do RNNs work? The basic idea is that an RNN has a recurrent layer that consists of a set of neurons that can store information over time. Each neuron has a hidden state that is updated at each time step based on the current input and the previous state. The hidden state acts as a memory that can encode the relevant information from the past inputs. The output of the RNN at each time step can be computed from the hidden state using another layer, such as a fully connected layer or a softmax layer.

Here is a simple example of an RNN that can process a sequence of words and generate a sentiment score for each word. The input is a one-hot vector that represents the word, and the output is a scalar value that represents the sentiment. The RNN has a recurrent layer with three neurons, and a fully connected layer with one neuron and a sigmoid activation function. The RNN is trained to assign positive scores to positive words and negative scores to negative words.

# Import libraries
import numpy as np
import tensorflow as tf

# Define the vocabulary and the sentiment scores
vocab = ["happy", "sad", "angry", "love", "hate"]
sentiment = [1, -1, -1, 1, -1]

# Define the input sequence and the expected output sequence
input_seq = ["happy", "love", "hate", "sad", "angry"]
output_seq = [1, 1, -1, -1, -1]

# Define the RNN parameters
input_size = len(vocab) # The size of the input vector
hidden_size = 3 # The size of the hidden state vector
output_size = 1 # The size of the output vector
learning_rate = 0.01 # The learning rate for gradient descent
num_epochs = 10 # The number of epochs for training

# Define the RNN model
class RNN(tf.keras.Model):
  def __init__(self, input_size, hidden_size, output_size):
    super(RNN, self).__init__()
    # Define the recurrent layer
    self.recurrent_layer = tf.keras.layers.SimpleRNN(hidden_size, return_sequences=True)
    # Define the output layer
    self.output_layer = tf.keras.layers.Dense(output_size, activation="sigmoid")

  def call(self, inputs):
    # Compute the hidden states for each time step
    hidden_states = self.recurrent_layer(inputs)
    # Compute the outputs for each time step
    outputs = self.output_layer(hidden_states)
    return outputs

# Create an instance of the RNN model
model = RNN(input_size, hidden_size, output_size)

# Define the loss function and the optimizer
loss_function = tf.keras.losses.MeanSquaredError()
optimizer = tf.keras.optimizers.Adam(learning_rate)

# Define a function to convert a word to a one-hot vector
def word_to_one_hot(word):
  # Initialize a zero vector with the size of the vocabulary
  one_hot = np.zeros(input_size)
  # Find the index of the word in the vocabulary
  index = vocab.index(word)
  # Set the element at the index to one
  one_hot[index] = 1
  # Return the one-hot vector
  return one_hot

# Define a function to convert a sequence of words to a batch of one-hot vectors
def seq_to_batch(seq):
  # Initialize an empty list to store the one-hot vectors
  batch = []
  # For each word in the sequence
  for word in seq:
    # Convert the word to a one-hot vector and append it to the batch
    one_hot = word_to_one_hot(word)
    batch.append(one_hot)
  # Convert the batch to a numpy array and return it
  batch = np.array(batch)
  # Add a dimension for the batch size
  batch = np.expand_dims(batch, axis=0)
  return batch

# Define a function to convert a scalar value to a sentiment label
def value_to_sentiment(value):
  # If the value is greater than 0.5, return "Positive"
  if value > 0.5:
    return "Positive"
  # If the value is less than 0.5, return "Negative"
  else:
    return "Negative"

# Train the RNN model
for epoch in range(num_epochs):
  # Convert the input sequence and the output sequence to batches of one-hot vectors
  input_batch = seq_to_batch(input_seq)
  output_batch = seq_to_batch(output_seq)
  # Run the model on the input batch and compute the loss
  with tf.GradientTape() as tape:
    predictions = model(input_batch)
    loss = loss_function(output_batch, predictions)
  # Compute the gradients and update the model parameters
  gradients = tape.gradient(loss, model.trainable_variables)
  optimizer.apply_gradients(zip(gradients, model.trainable_variables))
  # Print the epoch number and the loss value
  print("Epoch:", epoch + 1, "Loss:", loss.numpy())

# Test the RNN model on the input sequence
input_batch = seq_to_batch(input_seq)
predictions = model(input_batch)
# Print the input words, the predicted values, and the sentiment labels
for i in range(len(input_seq)):
  word = input_seq[i]
  value = predictions[0][i][0].numpy()
  sentiment = value_to_sentiment(value)
  print("Word:", word, "Value:", value, "Sentiment:", sentiment)

As you can see, the RNN model can learn to assign the correct sentiment scores to the words in the input sequence. However, this is a very simple example, and RNNs can handle much more complex and longer sequences. In fact, RNNs can also generate sequences, such as text or speech, by using the previous outputs as inputs. For example, you can use an RNN to generate a poem, a song, or a story, given some initial words or a topic.

However, RNNs also have some limitations and challenges, such as the vanishing or exploding gradient problem, the difficulty of learning long-term dependencies, and the high computational cost. To overcome these issues, there are some variants and extensions of RNNs, such as long short-term memory (LSTM) networks, gated recurrent units (GRU) networks, bidirectional RNNs, and attention mechanisms. You can learn more about these advanced topics in the references section.

4. How to Prevent Overfitting and Improve Generalization?

One of the main challenges of building robust neural networks is to prevent overfitting and improve generalization. Overfitting is a situation where a neural network performs well on the training data, but poorly on the test data or new data. Generalization is the ability of a neural network to perform well on unseen data that follows the same distribution as the training data. A good neural network should be able to generalize well and avoid overfitting.

Why does overfitting happen? There are several possible reasons, such as:

The training data is too small, noisy, or biased, and does not represent the true data distribution
The neural network is too complex, has too many parameters, or learns irrelevant features that are specific to the training data
The neural network is trained for too long, or with a too high learning rate, and memorizes the training data instead of learning the underlying patterns

How can you prevent overfitting and improve generalization? There are several techniques and methods that can help you achieve this goal, such as:

Using more and better data, that is diverse, balanced, and representative of the true data distribution
Using simpler and smaller neural networks, that have fewer parameters, or use sparsity or pruning techniques to reduce the number of parameters
Using regularization and normalization techniques, that penalize the complexity or the magnitude of the parameters, or normalize the inputs or the outputs of the layers
Using early stopping and learning rate decay techniques, that stop the training process or reduce the learning rate when the validation error starts to increase
Using data augmentation and dropout techniques, that artificially increase the size and the diversity of the training data, or randomly drop out some neurons or inputs during the training process

In the next sections, you will learn more about some of these techniques, especially dropout and other regularization techniques, and how they can help you build robust neural networks.

4.1. Dropout

One of the most popular and effective techniques to prevent overfitting and improve generalization is dropout. Dropout is a simple but powerful method that randomly drops out some neurons or inputs during the training process, with a certain probability. Dropout can be seen as a way of creating and training multiple neural networks with different architectures and parameters, and then averaging their outputs. Dropout can reduce the co-adaptation and the correlation of the neurons, and increase the diversity and the robustness of the neural network.

How does dropout work? The basic idea is that at each training step, you randomly select some neurons or inputs and set their values to zero, with a probability p, which is called the dropout rate. The dropout rate is usually between 0.2 and 0.5, depending on the layer and the task. The neurons or inputs that are not dropped out are scaled by a factor of 1/(1-p), to preserve the expected value of the layer. The dropout process is only applied during the training phase, and not during the testing or inference phase.

Here is a simple example of how to apply dropout to a fully connected layer in TensorFlow. The input is a vector of size 10, and the output is a vector of size 5. The dropout rate is 0.4, which means that 40% of the inputs are randomly dropped out at each training step. The output is computed by multiplying the input by a weight matrix, adding a bias vector, and applying a relu activation function.

# Import libraries
import numpy as np
import tensorflow as tf

# Define the input size, the output size, and the dropout rate
input_size = 10
output_size = 5
dropout_rate = 0.4

# Define the input vector
input = tf.random.uniform([input_size])

# Define the weight matrix and the bias vector
weight = tf.Variable(tf.random.normal([input_size, output_size]))
bias = tf.Variable(tf.random.normal([output_size]))

# Define the dropout layer
dropout_layer = tf.keras.layers.Dropout(dropout_rate)

# Apply dropout to the input vector
dropped_input = dropout_layer(input, training=True)

# Compute the output vector
output = tf.nn.relu(tf.matmul(tf.reshape(dropped_input, [1, input_size]), weight) + bias)

# Print the input vector, the dropped input vector, and the output vector
print("Input:", input.numpy())
print("Dropped input:", dropped_input.numpy())
print("Output:", output.numpy())

As you can see, the dropout layer randomly sets some elements of the input vector to zero, and scales the remaining elements by a factor of 1/(1-0.4) = 1.67. The output vector is then computed from the dropped input vector, and may vary depending on which elements are dropped out. By applying dropout, you can prevent the neural network from relying too much on specific inputs or features, and make it more robust and generalizable.

4.2. Other Regularization Techniques

Dropout is not the only regularization technique that can help you prevent overfitting and improve generalization. There are many other techniques that can also achieve this goal, such as:

L1 and L2 regularization: These are techniques that add a penalty term to the loss function, based on the magnitude of the parameters. L1 regularization uses the absolute value of the parameters, and L2 regularization uses the square of the parameters. L1 regularization can induce sparsity, which means that some parameters become zero and are effectively removed from the network. L2 regularization can prevent the parameters from becoming too large and overfitting the data.
Batch normalization: This is a technique that normalizes the inputs or the outputs of each layer, by subtracting the mean and dividing by the standard deviation. Batch normalization can reduce the internal covariate shift, which means that the distribution of the inputs or the outputs of each layer changes during the training process. Batch normalization can also speed up the convergence and improve the stability of the network.
Weight decay: This is a technique that reduces the value of the parameters by a small factor at each training step, before applying the gradient update. Weight decay can prevent the parameters from becoming too large and overfitting the data. Weight decay is equivalent to applying L2 regularization with a specific value of the penalty coefficient.
Noise injection: This is a technique that adds some random noise to the inputs or the outputs of each layer, during the training process. Noise injection can increase the robustness and the diversity of the network, and prevent it from memorizing the training data. Noise injection can also act as a form of data augmentation, by creating new and slightly different examples from the existing data.

These are some of the most common and widely used regularization techniques, but there are many others that can also be applied to neural networks, such as label smoothing, gradient clipping, spectral normalization, and more. You can learn more about these techniques and how to implement them in TensorFlow in the references section.

5. Conclusion

In this blog, you have learned how to build robust neural networks and use deep learning techniques to handle complex data such as images, text, and audio. You have explored some of the concepts and techniques that can help you improve the robustness of your neural networks, such as data preprocessing and augmentation, network architectures and hyperparameters, loss functions and optimization methods, regularization and normalization techniques, evaluation and validation methods, and defense and mitigation techniques. You have also learned about some of the types of deep neural networks that can deal with complex data, such as convolutional neural networks and recurrent neural networks. And you have learned about one of the most popular and effective regularization techniques for deep neural networks, dropout.

By following this blog, you have gained a better understanding of how to build robust neural networks and use deep learning for your data. You have also acquired some of the skills and tools that are necessary for implementing and testing your neural networks. We hope that this blog has been useful and informative for you, and that you will apply what you have learned to your own projects and problems.

If you want to learn more about robust neural networks and deep learning, you can check out some of the references that we have provided at the end of this blog. You can also find more resources and tutorials online, or enroll in some of the courses and programs that are available on the topic. And of course, you can always experiment and practice with your own data and neural networks, and see what results you can achieve.

Thank you for reading this blog, and we hope to see you again soon!

6. References

Here are some of the references that you can use to learn more about robust neural networks and deep learning. These references include books, articles, papers, courses, and websites that cover some of the topics and techniques that we have discussed in this blog. We have also provided the links to access these references online, as well as a brief description of each reference.

Deep Learning by Ian Goodfellow, Yoshua Bengio, and Aaron Courville. This is a comprehensive book that covers the theory and practice of deep learning, including neural network architectures, optimization methods, regularization techniques, adversarial examples, and applications. This book is suitable for beginners and experts alike, and it is available for free online.
Towards Robust Neural Networks via Random Self-ensemble by Cihang Xie, Jianyu Wang, Zhishuai Zhang, Zhou Ren, and Alan Yuille. This is a paper that proposes a novel technique for improving the robustness of neural networks against adversarial attacks, by using randomization and self-ensembling. The paper shows that this technique can achieve state-of-the-art results on several benchmark datasets and tasks.
Convolutional Neural Networks by Andrew Ng. This is a course that teaches you how to build and apply convolutional neural networks for various computer vision tasks, such as image classification, object detection, face recognition, and neural style transfer. This course is part of the Deep Learning Specialization on Coursera, and it requires some basic knowledge of deep learning and Python.
Dropout: A Simple Way to Prevent Neural Networks from Overfitting by Nitish Srivastava, Geoffrey Hinton, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. This is a paper that introduces dropout, a simple and effective regularization technique for neural networks, that randomly drops out units during training. The paper shows that dropout can reduce overfitting and improve generalization performance on various tasks and datasets.
Text classification with an RNN by TensorFlow. This is a tutorial that shows you how to build and train a recurrent neural network for text classification, using the TensorFlow framework and the IMDB movie review dataset. The tutorial also explains some of the concepts and features of recurrent neural networks, such as sequences, embeddings, and bidirectionality.

We hope that these references will help you deepen your understanding of robust neural networks and deep learning, and inspire you to explore more topics and techniques in this field. Happy learning!