COMP 578 Artificial Neural Networks for Data Mining Keith c.c. chan Department of Computing The Hong Kong Polytechnic University
1 COMP 578 Artificial Neural Networks for Data Mining Keith C.C. Chan Department of Computing The Hong Kong Polytechnic University
Human VS Computer Computers Not good at performing such tasks as visual or audio processing recognition Execute instructions one after another extremely rapidly Good at serial activities(e.g. counting, adding · Human brain Units respond at x 10/s(vS PV25GHz Work on many different things at once Vision or speech recognition by interaction of many different pieces of information
2 Human vs. Computer • Computers – Not good at performing such tasks as visual or audio processing/recognition. – Execute instructions one after another extremely rapidly. – Good at serial activities (e.g. counting, adding). • Human brain – Units respond at 10/s (vs. PV 2.5GHz). – Work on many different things at once. – Vision or speech recognition by interaction of many different pieces of information
The brain Human brain is complicated and poorly understood Contains approximately 1010 basic units called neurons Each neuron connected to about 10.000 others Dendrites Soma(or Cell Body) Axon Synapse
3 The brain • Human brain is complicated and poorly understood. • Contains approximately 1010 basic units called neurons. • Each neuron connected to about 10,000 others. Axon Dendrites Synapse Soma (or Cell Body)
The neuron Dendrites endre Soma Axon synapse Neuron accepts many inputs(through dendrites) Inputs are all added up in some fashion If enough active inputs are received at once, neuron will be activated and"fire"(through axon)
4 The Neuron • Neuron accepts many inputs (through dendrites). • Inputs are all added up in some fashion. • If enough active inputs are received at once, neuron will be activated and “fire” (through axon). Dendrites Axon Soma Synapse
The Synapse AXon produce voltage pulse called action potential(AP) Need arrival of more than one aP to trigger synapse Synapse releases neurotransmitters when AP is raised sufficiently Neurotransmitters diffuse across the gap chemically 0 activating dendrites on the L neurotransmitter.0 o other side 00,0 synaptic dett Some synapses pass a neurotransmitter large signal across, whilst others allow very little dendrite through
5 The Synapse • Axon produce voltage pulse called action potential (AP). • Need arrival of more than one AP to trigger synapse. • Synapse releases neurotransmitters when AP is raised sufficiently. • Neurotransmitters diffuse across the gap chemically activating dendrites on the other side. • Some synapses pass a large signal across, whilst others allow very little through