Data Science & ML

Deep Learning Fundamentals

Perceptrons, backpropagation, activation functions, loss functions, optimizers, batch size, epochs

24 interview questionsยท
Senior
1

What is a perceptron in the context of neural networks?

Answer

A perceptron is the basic unit of a neural network, inspired by biological neurons. It takes multiple inputs, multiplies them by weights, sums everything with a bias, then applies an activation function to produce an output. The simple perceptron can only solve linearly separable problems, which led to the development of multilayer networks.

2

What is the main limitation of the simple (single-layer) perceptron?

Answer

The simple perceptron can only solve linearly separable problems, meaning problems where classes can be separated by a straight line (or hyperplane in higher dimensions). This limitation, demonstrated by Minsky and Papert in 1969 with the XOR problem, temporarily slowed neural network research until multilayer perceptrons were introduced.

3

What is the role of the activation function in a neural network?

Answer

The activation function introduces non-linearity into the network, allowing it to learn complex relationships between inputs and outputs. Without a non-linear activation function, even a multi-layer network would behave as a simple linear transformation. Common functions include ReLU, sigmoid, and tanh, each with specific properties depending on the use case.

4

Which activation function is most commonly used in hidden layers of modern networks?

5

When should the softmax activation function be used in a neural network?

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