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Trigrams are a special case of the n-gram, where n is 3. They are often used in natural language processing for performing statistical analysis of texts and in cryptography for control and use of ciphers and codes .
Figure 1 shows several example sequences and the corresponding 1-gram, 2-gram and 3-gram sequences. Here are further examples; these are word-level 3-grams and 4-grams (and counts of the number of times they appeared) from the Google n-gram corpus. [4] 3-grams ceramics collectables collectibles (55) ceramics collectables fine (130)
Searching for this string in a database with a trigram-based index would involve finding which objects contain as many of the three trigrams as possible. As a concrete example of using trigram search to search for a regular expression query, consider searching for the string ab[cd]e, where the brackets denote that the third character in the ...
Weak ciphers do not sufficiently mask the distribution, and this might be exploited by a cryptanalyst to read the message. In cryptanalysis , frequency analysis (also known as counting letters ) is the study of the frequency of letters or groups of letters in a ciphertext .
n-grams find use in several areas of computer science, computational linguistics, and applied mathematics. They have been used to: design kernels that allow machine learning algorithms such as support vector machines to learn from string data [citation needed] find likely candidates for the correct spelling of a misspelled word [14]
For example, the BoW representation of "man bites dog" and "dog bites man" are the same, so any algorithm that operates with a BoW representation of text must treat them in the same way. Despite this lack of syntax or grammar, BoW representation is fast and may be sufficient for simple tasks that do not require word order.
The trifid cipher is a classical cipher invented by Félix Delastelle and described in 1902. [1] Extending the principles of Delastelle's earlier bifid cipher, it combines the techniques of fractionation and transposition to achieve a certain amount of confusion and diffusion: each letter of the ciphertext depends on three letters of the plaintext and up to three letters of the key.
In mathematics, a structure on a set (or on some sets) refers to providing it (or them) with certain additional features (e.g. an operation, relation, metric, or topology). Τhe additional features are attached or related to the set (or to the sets), so as to provide it (or them) with some additional meaning or significance.