Channel Coding When transmitting over a noisy channel, some of the bits are received with errors Example: Binary Symmetric Channel (BSc) Pe= probability oferror Q: How can these errors be removed? A: Coding: the addition of redundant bits that help us determine what was sent with greater accuracy
Information content of a random variable Random variable x Outcome of a random experiment Discrete R V takes on values from a finite set of possible outcomes PMF: P(X=y)=Py) How much information is contained in the event X=y? Will the sun rise today Revealing the outcome of this experiment provides no information Will the Celtics win the NBa championship? Since this is unlikely, revealing yes provides more information than revealing Events that are less likely contain more information than likely events
Failure modes Noises lead to failure modes(Fm) One set of noise values leads to fm Opposite set of noise values leads to FM Simple problem solving chases the problem from Fm, to Fm, and back again but does not avoid both fms with the same set of design values-endless cycles of build/test/fIx(B/T/F) C Don Clausing 1998 6.881
Case study An automatic document handler(adh)was developed at the ss level. When integrated into the total system there were many new problems. The TQM Problem Solving Process was used, and many problems were solved. However. at the field readiness Test (frt) before entering production the reliability was 15X worse than acceptable O Don Clausing 1998
