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In mathematical terms, Hamming codes are a class of binary linear code. For each integer r ≥ 2 there is a code-word with block length n = 2r − 1 and message length k = 2r − r − 1. Hence the rate of Hamming codes is R = k / n = 1 − r / (2r − 1), which is the highest possible for codes with minimum distance of three (i.e., the minimal ...
Investigations. The following investigations are used in clearance determinations: [ 12] ANACI (Access National Agency Check with Inquiries) – Initial Confidential, Secret, L, LX; only used for civilian employees. NACLC (National Agency Check with Law and Credit) – Initial Confidential, Secret, L, LX; reinvestigations.
Hamming (7,4) In coding theory, Hamming (7,4) is a linear error-correcting code that encodes four bits of data into seven bits by adding three parity bits. It is a member of a larger family of Hamming codes, but the term Hamming code often refers to this specific code that Richard W. Hamming introduced in 1950.
The Hamming weight of a string is the number of symbols that are different from the zero-symbol of the alphabet used. It is thus equivalent to the Hamming distance from the all-zero string of the same length. For the most typical case, a string of bits, this is the number of 1's in the string, or the digit sum of the binary representation of a ...
Top Secret is the highest level of classification. However some information is further categorized/marked by adding a code word so that only those who have been cleared for each code word can see it. A document marked SECRET (CODE WORD) could be viewed only by a person with a secret or top secret clearance and that specific code word clearance.
The only nontrivial and useful perfect codes are the distance-3 Hamming codes with parameters satisfying (2 r – 1, 2 r – 1 – r, 3), and the [23,12,7] binary and [11,6,5] ternary Golay codes. [4] [5] Another code property is the number of neighbors that a single codeword may have. [6] Again, consider pennies as an example.
Hamming bound. In mathematics and computer science, in the field of coding theory, the Hamming bound is a limit on the parameters of an arbitrary block code: it is also known as the sphere-packing bound or the volume bound from an interpretation in terms of packing balls in the Hamming metric into the space of all possible words.
Q clearance or Q access authorization is the U.S. Department of Energy (DOE) security clearance required to access Top Secret Restricted Data, Formerly Restricted Data, and National Security Information, as well as Secret Restricted Data. Restricted Data (RD) is defined in the Atomic Energy Act of 1954 and covers nuclear weapons and related ...