CMNS1234 Lecture Notes - Lecture 3: Warren Weaver
28 May 2018
School
Department
Course
Professor
Information Theory
• A model is an analogous shape given to a phenomenon for purposes of analysis.
• A theory is “some kind of simplifying device that allows you to decide which facts
matter and which do not.
• A theory can be used to describe, explain or predict.
• Descriptive theory
• Explanatory theory
• Predictive theory
Shannon and Weaver
• Claude Shannon developed a mathematical theory of signal transmission.
• aim was to solve the technical problems of high-fidelity transfer of sound.
• The context Shannon was working in was highly important.
• Shannon was quite cautious but his hesitation was not shared by Warren Weaver
• Shannon's theory was coupled with an interpretive essay by Weaver
• its source-channel-receiver diagram quickly became the standard description of what
happens when one person talks to another
•
• communication = an “intentional transfer of information from sender to receiver by
way of (physical) channels which are subject to noise and interference. According to
this model, communication is judged by the efficiency (volume and cost) and
effectiveness in achieving the planned 'transfer'” of information
• there are three levels the model operates on.
- Level A (technical problems) - How accurately can the symbols of communication
be transmitted?
- Level B (semantic problems) - How precisely do the transmitted symbols convey
the desired meaning ?
- Level C (effectiveness problems) - How effectively does the received meaning
affect conduct in the desired way? (Fiske 1990, p. 7).
- interrelated and interdependent
1. The mathematical theory of communication provided an objective approach to the
analysis of communication texts.
2. “information is simply stuff that matters or anything that makes a difference”
3. “information refers to the opportunity to reduce uncertainty. It gives us a chance to
reduce entropy”
What is Entropy?
4. “Entropy can best be understood as maximum unpredictability”
5. Information is thus defined by its opposite (randomness or chaos)”
What is Redundancy?
6. “Redundancy is that which is predictable or conventional in a message” and thus of
easy decoding”
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