CS 40 - Lecture 9

Cay S. Horstmann

Lecture 8 Recap

• object: item that can be manipulated in program (has instance variables, methods)
• class: set of objects with the same behavior
• instance of a class: an object of the class

Artificial Intelligence

What is artificial intelligence?

It is the science and engineering of making intelligent machines, especially intelligent computer programs.

What is intelligene?

Intelligence is the computational part of the ability to achieve goals in the world. Varying kinds and degrees of intelligence occur in people, many animals and some machines.

Source: John McCarthy, What is Artificial Intelligence, http://www-formal.stanford.edu/jmc/whatisai/

Example: DARPA Challenge

• Challenge: Build autonomous car (no human inside, no remote control)
• 2004, Mojave Desert: None got past 5% of the course
• 2005, Beer Bottle Pass: Five cars made the entire 212 km (132 mi), the winner (Stanford's Stanley) in just under 7 hours
• November 3, 2007, Victorville: Urban Challenge (http://www.darpa.mil/grandchallenge/index.asp). Drive through traffic
• Why the competition? (a) Obvious military use (b) Get American students excited about engineering

Example: Computer Chess

• Chess: Simple rules, but playing well is a challenge to most humans
• 1996: Deep Blue defeats world champion Garry Kasparov
• Extensive research on how humans play chess: planning, experience, intuition
• Chess programs try huge numbers of moves very quickly
• Are they intelligent?

Lab: Game of NIM

• You and the computer take turns taking marbles from pile. Each player takes at least 1 but at most half the marbles. Whoever is stuck with one marble loses.
• Try it out. Run the nim.a2w program in Alice. I used a combolock to indicate the number of marbles. Use left, right arrow key to turn, Enter key to mark your selection.
• Did you (1) win or (2) lose? ActiveLecture.org
• Look at the program (Cleopatra.play). Is this intelligence?
• For more exciting variation, go to http://www.2020tech.com/fruit/

Rule-Based Systems

• Use the power of logic
• Ingredients: (a) Facts (b) Rules of the form if A then B
• Advantage: Deductions are provably correct
• Applications: Credit rating, airline seat pricing, oil drilling, legal case analysis, automated stock trading, medical diagnostics

Probabilistic Methods

• Take probabilities into account
• Example: 95% probabilitiy that it will rain tomorrow
• Bayesian filtering, fuzzy logic
• Example: Spam filter computes prob. that message is spam, based on known probs. that words are contained in spam messages

Neural Networks

• Neural network: simulation of set of neurons in the brain
• Each connection has a weight factor
• Node is fired if sum of weighted inputs > 1
• Training phase: adjust weights if output not correct
• Example: Voice recognition
  

Lab: ELIZA

• Computer simulation of psychiatrist
• Joseph Weizenbaum 1966 (!)
• http://chayden.net/eliza/Eliza.html
• Try it out and have a dialog for a few minutes. What do you think? ActiveLecture.org
  1. Very convincing
  2. Must have been impressive in 1966
  3. Lame

Unsolved Challenges

• Language translation
• Accurate speaker-independent voice recognition
• Face recognition
• Proving mathematical theorems
• Giving useful advice
• Turing Test

What Works Today

• Resume scanning
• Credit card fraud detection
• Electronic pets
• Simple appliances

Ethical Issues

• You didn't get the interview/loan because the software rejected you. What is your recourse?
• The autonomous car ran over your dog. Who is liable?
• Face-recognizing cameras in all public spaces—surveillance society?
• SJSU in 50 years: Replace “expensive” faculty with software?

Your Turn

With your partner, formulate an ethical/societal issue related to the use of AI and write it here. ActiveLecture.org

Reminders

• Homework #3 is due next Tuesday
• Exam #1 is next Thursday
• Is your photo in eCampus? If not, please put it there.
• Start thinking about projects.
• Possible Topics:
  • Program something in Alice
  • Do something with movies (following the book)
  • Do research on social impact of computing