Systems Analysis and Synthesis

C.8. Chapter 8

1. Consider the merits of a check digit scheme that requires an Admission No to be divisible by 17.

The natural weights are

59641415101

They are all non-zero, and no two weights sum to 17. Therefore all single and double transcription errors will be detected. (Also, most triple transcription errors, but weights 6, 10, and 1 sum to 17, for example.)

All the weights are different, so all single transposition errors will be detected. No adjacent pairs have the same sum, so transpositions of pairs of digits will be detected too.

2. What does our inability to nest more than three interruptions tell us about the process of understanding the ...