COMP9444/9844 Neural Networks

Feedback Quiz on Hopfield Nets and BSB

This is a voluntary quiz to help you decide whether you have understood some of the major concepts from this topic. It carries no marks.

  1. Name three types of attractor in a dynamical system.

  2. What is a separatrix?

  3. What is the relationship between the sigmoid function 1/(1+exp(–x)) and the sigmoid function tanh(x/2) ?

  4. What is the energy function of the discrete Hopfield model?

  5. How do we know that the discrete Hopfield model will always settle into a fixed point from any initial condition?

  6. How do you store a set of fundamental memories ξμ in a Hopfield net?

  7. If y is a state in a Hopfield network, what does y = sgn(Wy + b) signify?

  8. What is a spurious stable state of a Hopfield net?

  9. What is the squashing function φ for the BSB model?

  10. What are the two equations that define the state udpate for the BSB model?
Solutions: don't read until you've tried the questions yourself.

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