Artificial Neural Networks and Applications Flashcards
What is a neural network?
a model that mimics the behavior of biological neurons in the human brain
How does a NN calculate an output?
passed input through an array of neurons
What kind of complicated problems do NN perform exceptionally well in solving?
text, voice, and image recognition, and NLP
What is a type of connectionist model that has become a mainstay of AI and cognitive science?
neural networks
Where does human intelligence begin?
with the connections between neurons
What are the three milestones in neural networks models?
Single layer perceptron, multi-layer perceptron, and DNN
Who founded the single layer perceptron model and when?
Rosenblatt in 1957
Who founded the multi-layer perceptron model and when?
Rumelhart in 1986
Who founded the DNN model and when?
Hinton in 2006
Which algorithm is a key algorithm of the single layer perceptron model?
the perceptron algorithm
Which algorithm is a key algorithm of the multi-layer perceptron model?
backpropagation algorithm
Which algorithm is a key algorithm of the DNN model?
deep learning algorithm
What is the main role common to all neural networks?
the learning function
What types of information are large-scale multimedia information?
audio and video information
True or false: Learning and recognizing data is small and easy to handle?
false
What structures comprise a neuron?
dendrites, synapses, axons, and terminals
What is the role of a neuron?
sensory organ neurons, network signaling
What are the components of a perceptron?
weights, bias, and activation functions
What is an activation function?
a function that expresses the activation/deactivation of a neuron
What are a few types of activation functions?
step-fn, sigmoid, tanh, and ReLU
Why do we use activation functions?
we need non-linear functions
What is the function of a dendrite?
receives stimuli from other neurons or surroundings and transmits impulses to cell body via electrical signals
What is a synapse?
the junction of cells where the axons of one neuron and the dendrites of the next neuron meet
What is an axon?
a branch of a neuron whose function is to transmit signals to other neurons
What is the function of a terminal?
receives transmitted electrical signals and secretes neurotransmitters into synapses
What happens to signals from sensory organs?
they pass through the brain’s network of neurons and get converted into meaningful signals
Where is the focus of current research?
implementing learning-capable computing
What is the behavior of a single neuron?
n inputs -> operation* (1 or 0) -> m outputs
What happens within the *operation (1 or 0) function?
neuron activates a signal when signal crosses a threshold according to rules of the cell body, or it does not emit a signal if it is not activated
What is the function of a weight?
controls the importance of the input signal to the output
What is the function of a bias?
controls how easily neurons are activated
What is the function of an activation function?
to pass vs not to pass
What are adjusted through learning?
weights and biases
Why are weights and biases adjusted through learning?
to strengthen neural networks of relevant signals and weaken unrelated neural networks
True or false: The activation function used for the neural network doesn’t matter?
false, you must choose the appropriate function
An activation function does what?
takes the sum of the inputs and calculates the output
When the sum of the inputs exceeds a certain threshold, what happens?
the neuron is activated
Neurons follow what type of activation function?
a step function
True or false: MLP (multilayer perceptrons) use a variety of activation functions?
true
True or false: All activation functions are nonlinear functions?
true
Why is it difficult to improve performance if you use a linear function as an activation function?
combining linear functions is the same as using one linear function so even if you have multiple layers, it’s really only expressed as one layer
What is a multilayer perceptron?
a perceptron that has a hidden layer between the input and output layers
What are MLPs notable for?
being able to distinguish data that is not linearly seperable
What do MLPs use for training the network?
backpropagation
What are the limitations of a MLP?
black box model and overfitting
What is the black box model?
since the perceptron is a black box, sometimes it is unknown how the network makes predictions or judgements
What is overfitting?
if the model is too complicated or the training data is too restricted, MLPs may easily overfit the training data
What is forward passage regarding MLPs?
the process by which input signals are applied to the input layer unit and these input signals are propagated through the hidden layer to the output layer
What is a loss function?
a mathematical function that measures the difference between predicted and actual values in a machine learning model
How does the loss function determine the model’s performance?
by comparing the distance between the prediction output and the target values