August
1999 QUESTION 5 Total Marks: 20 Marks |
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| (a) | Describe the basic biology of a neuron.
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[3] |
| (b) | A neuron has inputs x1 and x2, and the
corresponding weights w1 and w2. The values of the weights are 0.3 and 0.3 respectively.
The neuron uses a step function and has a threshold of 0.5. (i) Draw a diagram of a neuron, showing the formulae for the calculations (using the figures above) involved in calculating the output. (ii) Given that the inputs are x1=1 and x2=2, and has a target output of 1, calculate the output of this neuron. (iii) Explain how the weight can be adjusted so that the output eventually equals the target. (iv) What other threshold function is used and how does it differ from the step function?
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[3] [2] [3] [2] |
| (c) | (i) Name a supervised and an unsupervised
learning algorithm. (ii) Describe supervised learning in neural networks.
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[2] [5] |