Deep Learning: Classification Problems
45 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

How many gradient updates will the model perform after 5 epochs?

  • 3,135
  • 2,345 (correct)
  • 4,690
  • 1,000
  • What is the purpose of implementing the example from scratch in TensorFlow?

  • To replace Keras functionality entirely.
  • To reimplement backpropagation fully.
  • To understand basic tensor operations in depth.
  • To demonstrate understanding of deep learning mathematics. (correct)
  • What does the output of a Dense layer depend on?

  • The value of the activation function only.
  • The number of epochs completed.
  • The weights W and input, plus the bias b. (correct)
  • The network's architecture exclusively.
  • In the NaiveDense class, which method is responsible for applying the transformation?

    <p><strong>call</strong>()</p> Signup and view all the answers

    Which activation function is typically used for the last layer in a Dense layer implementation?

    <p>softmax</p> Signup and view all the answers

    What is the effect of updating the weights in the opposite direction from the gradient?

    <p>It will reduce the loss on each iteration.</p> Signup and view all the answers

    What does mini-batch stochastic gradient descent utilize?

    <p>A random subset of samples for each iteration.</p> Signup and view all the answers

    What is a naive solution for adjusting the weight coefficient in a model?

    <p>Freeze all weights except the one being considered and test different values.</p> Signup and view all the answers

    If changing the weight coefficient from 0.3 to 0.35 increases the loss, what can be inferred?

    <p>Increasing the coefficient decreases the model's performance.</p> Signup and view all the answers

    Why is it important to select a reasonable value for the learning rate?

    <p>It influences the speed of descent on the loss curve.</p> Signup and view all the answers

    What is true stochastic gradient descent?

    <p>It uses a single sample at each iteration.</p> Signup and view all the answers

    Why is adjusting coefficients one at a time in a model not efficient?

    <p>Each adjustment requires computing two forward passes.</p> Signup and view all the answers

    What is the primary optimization technique used in modern neural networks?

    <p>Gradient descent.</p> Signup and view all the answers

    What might happen if the learning rate is set too high?

    <p>The updates may overshoot and diverge randomly.</p> Signup and view all the answers

    What characteristic of functions used in models allows for gradient-based optimization?

    <p>They are differentiable and change smoothly.</p> Signup and view all the answers

    What does batch gradient descent do differently compared to mini-batch SGD?

    <p>It performs updates based on the entire dataset.</p> Signup and view all the answers

    What is the role of the gradient in training a neural network?

    <p>It shows the direction in which to adjust coefficients to minimize loss.</p> Signup and view all the answers

    What primarily differentiates mini-batch SGD from true SGD?

    <p>The batch size of samples drawn.</p> Signup and view all the answers

    What happens when the weight coefficient is decreased from 0.3 to 0.25?

    <p>The loss decreases, suggesting better model performance.</p> Signup and view all the answers

    Which is a consequence of having a learning rate that is too small?

    <p>The model may get stuck in local minima.</p> Signup and view all the answers

    What is one of the disadvantages of relying solely on one-at-a-time coefficient adjustments?

    <p>It ignores the interactions between different coefficients.</p> Signup and view all the answers

    What will happen if the optimization process using SGD is executed with a small learning rate near a local minimum?

    <p>The process could get stuck at the local minimum.</p> Signup and view all the answers

    How does momentum help in the context of SGD optimization?

    <p>It helps the optimization 'ball' move past local minima towards the global minimum.</p> Signup and view all the answers

    In the context of the algorithm presented, which variable represents the current velocity?

    <p>velocity</p> Signup and view all the answers

    What role does the momentum factor play in the optimization process?

    <p>It amplifies the effect of past gradients.</p> Signup and view all the answers

    What is a potential issue when calculating gradients for complex expressions in backpropagation?

    <p>The gradients might become unstable.</p> Signup and view all the answers

    Which statement best describes how to update the parameter 'w' in the provided momentum implementation?

    <p>The velocity is first calculated and then added to w using both past and current acceleration/gradient.</p> Signup and view all the answers

    What can occur if a small ball simulates the optimization process and lacks sufficient momentum?

    <p>It may settle in a local minimum.</p> Signup and view all the answers

    Which aspect of the gradient-based optimization is emphasized in the content?

    <p>Maintaining convergence stability is crucial in training neural networks.</p> Signup and view all the answers

    What is the primary difference between classification and regression in supervised learning?

    <p>Classification deals with labeled data of classes, regression deals with continuous scale values.</p> Signup and view all the answers

    Which of the following is a method of unsupervised learning?

    <p>K-means clustering</p> Signup and view all the answers

    Which of the following statements about K-means clustering is true?

    <p>K-means clustering uncovers structure in unlabeled data.</p> Signup and view all the answers

    What is meant by 'labels on a continuous scale' in regression?

    <p>Labels that can take any value within a range.</p> Signup and view all the answers

    Which unsupervised learning method focuses on reducing the dimensions of data?

    <p>Principal Component Analysis (PCA)</p> Signup and view all the answers

    Which statement accurately describes unsupervised learning?

    <p>It finds hidden patterns without needing labeled outcomes.</p> Signup and view all the answers

    What kind of data is typically used in classification tasks?

    <p>Labeled data categorized into classes</p> Signup and view all the answers

    Which of the following best describes supervised learning?

    <p>Learning that uses input-output pairs with known results.</p> Signup and view all the answers

    What does the forward pass in a computation graph entail?

    <p>Calculating values from input nodes to loss.</p> Signup and view all the answers

    In the backward pass, what is represented by grad(B, A)?

    <p>The rate of change of B with respect to A.</p> Signup and view all the answers

    If grad(loss_val, x2) = 1, what does this imply about the relationship between loss_val and x2?

    <p>A change in x2 results in a proportional change in loss_val.</p> Signup and view all the answers

    How does grad(x2, x1) = 1 affect the relationship between x2 and x1?

    <p>A change in x1 causes an equivalent change in x2.</p> Signup and view all the answers

    What does grad(x1, w) = 2 indicate about x1 when w varies?

    <p>x1 doubles for each increment of w.</p> Signup and view all the answers

    What role does variable b play in the relationship for grad(x2, b)?

    <p>It has a direct proportionality with the change of x2.</p> Signup and view all the answers

    What does the concept of reversing the graph during the backward pass help to determine?

    <p>It clarifies how inputs affect outputs.</p> Signup and view all the answers

    What is the significance of annotating edges with gradient values during the backward pass?

    <p>It indicates the relative impact of each variable.</p> Signup and view all the answers

    Study Notes

    Deep Learning: Classification

    • Classification problems involve predicting the category or class of an input.
    • Examples include spam detection (is an email spam or not?), image recognition (is this a picture of a cat, dog, or bird?), and sentiment analysis (is this review positive or negative?).
    • Data for classification problems includes both input features and corresponding labels.
    • Binary classification means dividing items into two categories (spam/not spam).
    • Multi-class classification involves more than two categories (e.g., classifying images of different fruits).
    • Multilabel classification allows for multiple labels assigned to a single input (e.g., tagging an article with multiple topics).

    Example Classification Problems

    • Examples of binary classification problems include spam detection and image recognition (cat vs. dog).
    • Multi-class classification examples include image recognition with multiple classes (e.g. classifying images of different types of fruits).
    • Multi-label classification examples include articles that can be tagged with multiple topics.

    Binary vs. Multi-Class Classification

    • Binary classification deals with two classes.
    • Multi-class classification deals with more than two classes.

    What We're Going To Cover

    • Neural network architecture for classification.
    • Input and output shapes of a classification model.
    • Creating custom data for classification tasks.
    • Model building steps, including loss functions, optimizers, training, and evaluation.
    • Model saving and loading.
    • Harnessing non-linearity in models.
    • Different classification evaluation methods.

    Classification Inputs and Outputs

    • Input data often consists of normalized pixel values.
    • Output is a probability distribution over the possible categories.

    Input and Output Shapes

    • Input data structure for image classification often involves batch size, color channels, width, and height dimensions.
    • Output structure often includes the predicted category and its probabilities.

    Architecture of a Classification Model

    • Models usually consist of multiple layers: input, hidden layers, and output.
    • These layers use parameters like input layer shape, hidden layers (neurons per layer), output layer shape, and activation functions.
    • Loss functions are used to quantify the difference between predicted and true output.
    • Optimizers (e.g., SGD, Adam) adjust model parameters to improve accuracy.

    Improving A Model

    • Adding layers or increasing the number of hidden units can improve model complexity.
    • Changing activation functions (like ReLU and sigmoid) can alter how the model processes information.
    • Choosing a different optimization function (e.g., Adam, instead of SGD) can influence how the model learns.
    • Adjusting the learning rate can affect the speed and stability of training.
    • Increasing training time (epochs) can improve a model in many cases but results in overfitting sometimes.

    The Missing Piece: Non-linearity

    • Linear models can't capture complex relationships in data.
    • Adding non-linear activation functions (e.g., sigmoid, ReLU) allows models to learn complex patterns.
    • These functions introduce non-linearity into the model and allow for a flexible representation of complex data.

    The Machine Learning Explorer's Motto

    • Visualize, visualize, visualize (data, model, training, predictions)

    The Machine Learning Practitioner's Motto

    • Experiment, experiment, experiment.

    Steps in Modelling With PyTorch

    • Construct a model.
    • Prepare the loss function, optimizer, and training loop.
    • Train the model(fit the model) on training data.
    • Evaluate the model on test data(how reliable the model's predictions are).

    Classification Evaluation Methods

    • Accuracy measures correct predictions overall.
    • Precision measures the proportion of true positive predictions out of all positive predictions.
    • Recall measures the proportion of true positive predictions out of all actual positive values.
    • F1-score combines precision and recall.
    • Confusion matrices show the counts of different types of predictions.

    Anatomy of a Confusion Matrix

    • True positive (TP): model predicts 1 when truth is 1.
    • True negative (TN): model predicts 0 when truth is 0.
    • False positive (FP): model predicts 1 when truth is 0.
    • False negative (FN): model predicts 0 when truth is 1.

    Three Datasets (Training, Validation, and Test)

    • Training set: used by the model to learn patterns.
    • Validation set: used to tune model parameters.
    • Test set: used to evaluate the model.

    Neural Network Learning Steps

    • Initialize weights and biases with random values.
    • Input data is encoded numerically.
    • Show data to the neural network, get outputs using the forward pass.
    • Update weights based on the difference between predicted vs. actual outputs using back propagation

    Learning Strategies

    • Supervised learning (discrete and continuous) involves labeled data.
    • Unsupervised learning (e.g., clustering, dimensionality reduction) uses unlabeled data.

    Unsupervised Learning Methods

    • Hierarchical clustering.
    • K-means clustering.
    • Principal Component Analysis (PCA).
    • Singular Value Decomposition.
    • Independent Component Analysis.

    Conclusion (Supervised Learning)

    • Labeled data (inputs paired with labels) is essential.
    • Classification labels are categorical, and regression labels are continuous.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Description

    This quiz explores various classification problems in deep learning, including binary, multi-class, and multilabel classification. Understand how different classification techniques are applied in practical scenarios such as spam detection, image recognition, and sentiment analysis.

    Use Quizgecko on...
    Browser
    Browser