String (computer science)

About: String (computer science) is a research topic. Over the lifetime, 19430 publications have been published within this topic receiving 333247 citations. The topic is also known as: str & s.

Data compression apparatus with shift register search means

Abstract: An apparatus and method are disclosed for converting an input data character stream into a variable length encoded data stream in a data compression system. The data compression system includes a shift register means. The shift register means has a plurality of entries and each entry of the shift register means is for storing a data character of the input data stream. The method for converting the input data character stream includes the following steps. Performing a search in the shift register means for a data string which matches the input data string. The step for performing the search includes the steps of broadcasting each input data character of the input data stream to each entry of the shift register means and comparing each input data character simultaneously with the previously stored contents of each entry of said shift register means. If the matching data string is found within the shift register means, the next step includes encoding the longest matching data string by appending to the encoded data stream a tag indicating the matching data string and a string substitution code. If the matching data string is not found within the shift register means, the next step includes encoding the first character of the input data string by appending to the encoded data stream a raw data tag and the first character of the input data string.

Approximate String-Matching over Suffix Trees

Abstract: The classical approximate string-matching problem of finding the locations of approximate occurrences P′ of pattern string P in text string T such that the edit distance between P and P′ is ≤ k is considered. We concentrate on the special case in which T is available for preprocessing before the searches with varying P and k. It is shown how the searches can be done fast using the suffix tree of T augmented with the suffix links as the preprocessed form of T and applying dynamic programming over the tree. Three variations of the search algorithm are developed with running times O(mq + n), O(mq log q + size of the output), and O(m2q + size of the output). Here n = ¦T¦, m = ¦P¦, and q varies depending on the problem instance between 0 and n. In the case of the unit cost edit distance it is shown that q = O(min(n, mk+1¦∑¦ k )) where ∑ is the alphabet.

Statistical Machine Translation by Parsing

Abstract: In an ordinary syntactic parser, the input is a string, and the grammar ranges over strings. This paper explores generalizations of ordinary parsing algorithms that allow the input to consist of string tuples and/or the grammar to range over string tuples. Such algorithms can infer the synchronous structures hidden in parallel texts. It turns out that these generalized parsers can do most of the work required to train and apply a syntax-aware statistical machine translation system.

Phonetic decoding and concatentive speech synthesis

Abstract: A speech processing system includes a multiplexer that receives speech data input as part of a conversation turn in a conversation session between two or more users where one user is a speaker and each of the other users is a listener in each conversation turn A speech recognizing engine converts the speech data to an input string of acoustic data while a speech modifier forms an output string based on the input string by changing an item of acoustic data according to a rule The system also includes a phoneme speech engine for converting the first output string of acoustic data including modified and unmodified data to speech data for output via the multiplexer to listeners during the conversation turn

Apparatus and method for very high data rate-compression incorporating lossless data compression and expansion utilizing a hashing technique

Abstract: A method and apparatus for compressing digital data that is represented as a sequence of characters drawn from an alphabet. An input data block is processed into an output data block composed of sections of variable length. Unlike most prior art methods which emphasize the creation of a dictionary comprised of a tree with nodes or a set of strings, the present invention creates its own pointers from the sequence characters previously processed and emphasizes the highest priority on maximizing the data rate-compression factor product. The use of previously input data acting as the dictionary combined with the use of a hashing algorithm to find candidates for string matches and the absence of a traditional string matching table and associated search time allows the compressor to very quickly process the input data block. Therefore, the result is a high data rate-compression factor product achieved due to the absence of any string storage table and matches being tested only against one string.