CLAUDE E. SHANNON
EXAMPLE OF
COMMUNICATION THEORY MODEL
Noise
v
Source ------> Sender ------> Channel------>Receiver------>Destination
^
Equivocation
Shannon’s model is used for flow of information in many settings. This example loosely follows Shannon’s model. In the following examples, we see an imaginary library where 1,000 books have been donated and left scattered in an empty room. A fictional patron is searching for The Life of Abe, a biography, a red book she knows is somewhere in the pile of donated books. The fictional "cataloger" has a lot to learn!
| Cataloger | Shelver | Books | Patron |
| Wants the books picked up and put on shelves. | Shelves the books randomly. | Are in a sequence but it is without meaningful order. High entropy, low order. | Has to search through 500 books on the average to find desired book. |
| "Classifies" 500 books as red and 500 books as blue. | Shelves 500 books in the Red Room and 500 in the Blue Room. | Books in each room are randomly shelved. | Knows to look in the Red Room. Searches 250 on average to find hers. |
| Sorts books by category: Mystery, Fiction, Biography, Science. | Starts over, shelving by category. | Are randomly shelved within category. | Searches through 125 biographies on average to find hers. |
| Learns Dewey Decimal Classification. | Makes mistakes shelving by DDC rules. | Are for the most part in DDC order. | Locates her book with some difficulty. |
| Uses DDC. | Shelves perfectly. | Are in perfect DDC order. Low entropy, high order. | Locates her book with no problem. |
In the first library there is disorder or high "noise" and "entropy." The order of the books on the shelves gives no clear message about where to find a particular book. The books are in a sequence but it does not give information on a book’s location. There is no clear message.
As the catalog tries different ways to lower the entropy, he increases the chances that the patron will find her book. With the Dewey Decimal Classification used well and followed perfectly by the shelver, the order is presumably perfect. Entropy is now extremely low and there is a meaningful message as to where to locate the book.
There is always the element of error in shelving, whether by the overworked shelver or a patron. This creates another problem with disorder which could be solved by sequential scanning of the entire collection. The scanning could be followed by an analysis of the types of errors and a greater understanding statistically of where incorrectly shelved books are likely to be found relative to their proper place. Are they on the shelf above or below? Is there an inversion of a DDC call number? Is there a problem with theft? The process is another example of discerning a message, gathering information amidst a good deal of disorder or entropy.