What is Artificial Intelligence? AI is the effort to develop systems that can behave/act like humans. Turing Test The problem = unrestricted domains –human intelligence vastly complex and broad –associations, metaphors, and analogies –common sense –conceptual frameworks

Elements of AI Natural Language Processing Robotics Perceptive Systems (Vision) Expert Systems

How are Machines Intelligent? Constrained Heuristic Search –How do you play chess? first move = 20 possible second move = 400 possible 7th move = 1,280,000,000 possible –Depth First vs. Breath First Searching –Ability to Learn

Decision Tree

Depth First Search

Breath First Search

Expert Systems Capture knowledge of an expert. Represent Knowledge as a –rule base if then rules –semantic netsemantic net hierarchy –framesframes shared characteristics, IS-A relationships

Expert System Successes XCON - configures systems for DEC Prospector - an mining expert MYCIN - infectious blood diseases EMYCIN - Empty MYCIN

Elements of Expert System Shell Knowledge Base –rules Working Memory –facts of current case Inference Engine –applies rules using current set of facts Explanation Facility CLIPS

Neural Networks & The Brain Base on architecture of human brain –Neurons connected by axons & dendrites –100 billion neurons –1,000 dendrites per neuron –100,000 billion synapses –10 million billion interconnectons per second

How a Neuron Works Impulses come from other neurons. When sum of inputs reaches a threshold, neuron fires. Sending impulses to next level of neurons.

An Artificial Neural Network Inputs Hidden Output w w w w w w

Neural Networks, NN NNs learn by using a training set and adjusting the weights on each connection. NNs do not have to be “told” explicit relationship rules. NNs can work with partial inputs. NNs cannot explain their results. NNs can take a long time to train. A NN demonstration