1. Week 5 - Friday
CS 113

2. Last time What did we talk about last time? Simulation and modeling
Bioinformatics
If statements in Python

3. Project 2

4. Questions?

5. Artificial Intelligence

6. Artificial intelligence
Artificial intelligence (AI) is hard to define
Trying to make machines think?
Goals
Problem solving
Representing knowledge
Creating machines that can learn
Natural language processing
Interpreting and interacting with the physical world and humans
Creativity
General intelligence is perhaps the combination of all these things
Achieving general intelligence is sometimes called strong AI

7. Approaches
There are many approaches for generating various aspects of artificial intelligence
Simulating the human brain
Like with Blue Gene
Symbolic approaches
Views all intelligence as manipulating symbols
Sub-symbolic approaches
Became popular in the 1980s
Tries to process data without directly manipulating symbols
Statistical approaches
Combinations

8. i Neural networks Neural networks are a popular sub-symbolic tool
They are composed of simple nodes that take numerical inputs and add them together with different weights
By adjusting the weights, you can train a group of nodes to solve a problem
There are handwriting recognizers and speech recognizers that use neural networks i

9. Statistical approaches
In the 1990s, statistical approaches became popular
For example, you can analyze language statistically and
Find rarely used words, are some of them misspelled?
Find buzzwords
Link different search terms together
Know that this phrase in Farsi is almost always translated into that phrase in English
Most of Google's success in AI has been statistical
Like neural networks, statistical models of how speech (or other intelligent behavior) is formed tend to give us little insight into how intelligence works
But they work!

10. Turing test Alice: Are you a human? Bob: What else would I be?
Alan Turing, a great early computer scientist, argued that acting like a human being was proof of intelligence
In the Turing test, person A (call her Alice) texts with entity B (call him Bob)
Bob could be a computer or a human
If a computer can reliably fool Alice into thinking is a human, it is displaying human intelligence
Alice: Are you a human?
Bob: What else would I be?
Alice: Do you like pie?
Bob: The value of pi is approximately

11. Chinese Room
John Searle proposed an argument against symbolic AI and the Turing test:
Imagine a room filled with rules to manipulate symbols
A man in the room receives symbols written on paper slipped through a slot in the door
He follows the rules, creates new symbols, writes them on paper, and slips them back out the slot
The symbols are actually Chinese characters
Because the rules are complex enough, the Chinese speaker on the outside believes that she is interacting with someone who understands Chinese
Does the man in the room understand Chinese?
Do our brains understand English or are they just manipulating symbols?

12. Evil AI So, what about the evil AI we see in movies?
Will Skynet take over the world?
Computers are stupid
They follow our instructions blindly (though quickly)
Maybe some of the brain simulation research will lead to a machine with human intelligence
At the moment, we are very far away
Some people like Ray Kurzweil think that change will happen fast
If computers become intelligent enough to write programs, who knows what could happen?
I'm not worried

13. Siri The most impressive feature of Siri is her voice recognition
Some is done on the device, some is done in the cloud
After that, some statistical work is done to decide what your command or question means
And how good is it?
For a limited set of commands that relate directly to iPhone functions (playing songs, calling contacts), it's great
Apple engineers put in some clever answers to a few set questions
Otherwise, it gets disappointing fast

14. Review of while loops
The while loop runs as long as a condition is true
In this case, when countdown becomes 0, the loop stops (since 0 is not less than 0)
Note that while loops use the same relational operators as if statements
countdown = 10
while countdown > 0:
print(countdown)
countdown = countdown – 1
print("Blast-off!")

15. Review of for loops
If you want to do something, say, 10 times in Python, you can use a for loop
But you need to call the range() method to generate a list of numbers for you
In this case, the loop will run 10 times, and the numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 will print out
for i in range(10):
print(i)

16. Review of Python if statements
In Python, the primary way to make a choice is with an if statement
Whatever code is under the if and tabbed in will only be executed if the condition is true
Optionally, an else section can be added if you want to do something if the condition is false
Conditions often use the following relational operators to make a comparison: ==, !=, <, <=, >, >=
if phrase == "open sesame":
print("Welcome, Ali Baba!")
else:
print("Access denied!")

17. Multiple conditions
The if and else constructs allow us to choose between two possibilities
What if we wanted more?
We can extend these constructs with elif to handle additional conditions

18. elif elif is short for "else if"
It's used when the prior condition wasn't true and we want to check another condition
if number == 1:
print("First")
elif number == 2:
print("Second")
elif number == 3:
print("Third")
else:
print(number + "th")

19. Use of elif
The elif construct if used if you want a bunch of mutually exclusive outcomes
Only one of the choices is possible
It is very common to end a sequence of if, elif, elif, elif, … statements with an else, whose code will be executed if none of the previous cases was true
However, the else is not used if there's nothing to be done when no case matches

20. Lab 5

21. Upcoming

22. Next time…
Graph theory

23. Reminders
Start working on Project 2
Read Python Chapter 5