(c) Epstein, Carter & Bollinger
2016
Exam 3 Review
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Exam 3 Topics
Chapter 16 – Identification Numbers
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Know what 𝑎 mod 𝑚 ≡ 𝑏 means (section 17.1 in the book).
Be able to calculate 𝑥 𝑚𝑜𝑑 𝑦 (section 17.1 in the book).
Understand the purpose of a check digit.
Know the most common types of errors (single-digit errors, adjacent transpositions, jump transpositions) that can
occur when dealing with identification numbers.
When given the scheme to determine a check digit, be able to
o Find the check digit.
o Determine if a code is valid.
o Find a missing value in the code if the check digit is given.
o Determine which errors are and are not caught by the check digit scheme.
Know which digits of a zip code signify the geographic region, section facility, and local delivery areas.
Recognize a bar code.
Given a chart of symbols, write or decode a bar code.
Given an identification number and the scheme, use it to code or decipher the information such as birth date and
gender.
Chapter 17 – Information Science
 Know what a binary code is.
 Know how to convert from binary numbers (base two) to decimal numbers (base ten) and decimal numbers to
binary numbers.
 Use error checking to determine or verify a code word, given the message and the error checking method.
 Be able to compute check digits for code words using the Venn Diagram that symbolized the parity-check sum
scheme used in the notes.
 When there is a single error, be able to correct code words using the Venn Diagram that symbolized the paritycheck sum scheme used in the notes.
 Be able to compute check digits for code words given the parity-check sums for the code.
 Be able to determine the distance between two strings.
 Be able to determine the weight of a binary code and use the weight to determine the error detecting/correcting
abilities of the code.
 Know what nearest-neighbor decoding is and be able to use it for decoding messages.
 Be able to encode and decode messages that have symbols (such as letters of the alphabet) expressed in binary
form when the coding scheme is provided.
 Use delta encoding to compress or expand data.
 Be able to create a Huffman code given a table of probabilities and use it to encode a message.
 Be able to decode using a Huffman code.
 Be able to encrypt and decrypt messages using the Caesar, decimation, and Vigenère ciphers.
 Be able to add binary strings.