CS 4341 Homework #2

Due Tuesday, March 25

Solutions

Reading: Chapters 7, 8, and 9 of Artificial Intelligence.
HW Instructions:
Same as last time. But be sure you supply "hw2" as an argument to turnin. See the turnin page for more information.
Problems:
1. List your project partners.
2. Exercise 4.5. Show the nodes that are examined at each level; you do not have to show closed nodes that do not get expanded.
3. Exercise 7.2.
4. Exercise 8.2.
5. Run zoobk.exp and zoofw.exp located in /cs/cs4341/ai3. Just watch and understand. You do not have to turn anything in.
6. Run bagger.exp. Nothing to turn in, either.
7. Optional:
  This problem is required for students taking CS 4341 for graduate credit under the BS/MS program, optional for everyone else.
  When running zoobk.exp, you should have seen that Sandy is identified as an ostrich. However, in forward chaining, Sandy is identified as two kinds of bird. To see this, enter the following (assuming that your current directory is /cs/cs4341/ai3):
```
(load "match.lsp")
(load "streams2.lsp")
(load "forward.lsp")
(load "zoo.lsp")

(progn (make-zoo-rules)
       (make-sandy)
       (chain))
```
  Answer these questions:
  1. Explain why the backward chaining system picks Ostrich and not Penguin.
  2. Using the same facts and rules, under what circumstances (different rule order, different ordering of clauses, etc.) would backward chaining pick Penguin?
  3. How could you modify the rules in forward chaining to ensure that an animal is identified as only a single species, even though it may satisfy the rules for more than one species?
You should turn in files
hw2_1.txt
hw2_2.txt
hw2_3.txt
hw2_4.txt
Optional
hw2_7.txt

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