Showing papers on "String (computer science) published in 1975"

Efficient string matching: an aid to bibliographic search

Abstract: This paper describes a simple, efficient algorithm to locate all occurrences of any of a finite number of keywords in a string of text. The algorithm consists of constructing a finite state pattern matching machine from the keywords and then using the pattern matching machine to process the text string in a single pass. Construction of the pattern matching machine takes time proportional to the sum of the lengths of the keywords. The number of state transitions made by the pattern matching machine in processing the text string is independent of the number of keywords. The algorithm has been used to improve the speed of a library bibliographic search program by a factor of 5 to 10.

An Extension of the String-to-String Correction Problem

Abstract: The string-to-string correction problem asks for a sequence S of "edit operations" of minimal cost such that ~(A) = B, for given strings A and B The edit operations previously investi- gated allow changing one symbol of a string into another single symbol, deleting one symbol from a string, or inserting a single symbol into a string This paper extends the set of allowable edit opera- tions to include the operation of interchanging the positions of two adjacent characters Under certain restrictions on edit-operation costs, it is shown that the extended problem can still be solved in time proportional to the product of the lengths of the given strings

Design of a linguistic statistical decoder for the recognition of continuous speech

Abstract: Most current attempts at automatic speech recognition are formulated in an artificial intelligence framework. In this paper we approach the problem from an information-theoretic point of view. We describe the overall structure of a linguistic statistical decoder (LSD) for the recognition of continuous speech. The input to the decoder is a string of phonetic symbols estimated by an acoustic processor (AP). For each phonetic string, the decoder finds the most likely input sentence. The decoder consists of four major subparts: 1) a statistical model of the language being recognized; 2) a phonemic dictionary and statistical phonological rules characterizing the speaker; 3) a phonetic matching algorithm that computes the similarity between phonetic strings, using the performance characteristics of the AP; 4) a word level search control. The details of each of the subparts and their interaction during the decoding process are discussed.

A New Linear-Time ``On-Line'' Algorithm for Finding the Smallest Initial Palindrome of a String

Abstract: Despite significant advances in linear-time scanning algorithms, particularly those based wholly or in par t on either Cook's linear-time simulation of two-way deterministic pushdown automata or Weiner's algorithm, the problem of recognizing the initial leftmost nonvoid palindrome of a string in time proportional to the length N of the palindrome, examining no symbols other than those in the palindrome, has remained open. The present algorithm solves this problem, assuming tha t addition of two integers less than or equal to N may be performed in a single operation. Like th e Knuth-Morris-Prat t algorithm, i t runs in time independent of the size of the input alphabet. T h e algorithm as presented finds only even palindromes. However, an extension allows one to recognize the initial odd or even palindrome of length 2 or greater. Other easy extensions permit the recognition of strings (wwR) * of even palindromes and of all the initial palindromes. I t appears possible tha t further extension may be used to show tha t (wwR) * is in a sense recognizable in real time on a reasonably defined random access machine. xEv WORDS AND PHa~SES: linear-time algorithm, on-line recognition, palindrome CR CATEGORIES: 5.22, 5.25, 5.30

The role of orthographic and phonotactic rules in perceiving letter patterns.

Abstract: Three experiments examined the role of orthographic and phonotactic rules in the tachistoscopic recognition of letter strings. Experiment 1 showed that the presence of a vowel or multiletter spelling patterns facilitates perceptual accuracy. To account for these results a model was proposed in which an input string is first parsed into syllablelike units, which are then recorded into speech. It was demonstrated that the perceptual accuracy for a string is correlated with the number of recoding steps needed to convert that string into speech. Experiment 2 further demonstrated that this recoding process can predict perceptibility differences among strings with varying numbers of phonotactic violations, and Experiment 3 assessed some of the specific assumptions of the recoding process.

String of pearls

Abstract: PEARLS are succinct summaries of Cochrane Systematic Reviews for primary care practitioners—developed by Prof. Brian McAvoy for the Cochrane Primary Care Field (www.cochraneprimarycare. org), New Zealand Branch of the Australasian Cochrane Centre at the Department of General Practice and Primary Health Care, University of Auckland (www.auckland.ac.nz/uoa), funded by the New Zealand Guidelines Group (www.nzgg.org.nz) and published in NZ Doctor (www.nzdoctor.co.nz.). Spironolactone (when all else fails) in hypertension

Method for determining the pump-off of a well

Abstract: A method for monitoring a rod pumped well and determining when the well has pumped off. The method uses a dynamometer to monitor the power input to the rod string and senses when the power input decreases to determine when the well pumps-off.

Word recognition apparatus

Abstract: A word recognition apparatus using a dictionary of words is disclosed. The apparatus comprises, first of all, word storing means which stores words based on the classification of a plurality of words to be retrieved in block units. The words are stored in the order of block numbers so that characters placed in one or more given positions of a word forming an input character string may be used as a retrieving key. A block-starting-address storing means is provided for storing starting addresses of the clock units in the word storing means. A block-starting-address and limit-address taking-out means takes out a block starting address corresponding to a designated block number and a block limit address corresponding to a block number next to the designated number from the blockstarting-address storing means. An input-character-string storing means stores the string of characters recognized by a character recognition system. A block-number determining means responsive to the input-character-string storing means sequentially designates the number of blocks containing words having recognized characters of characters placed in the retrieving key positions of the input character string. A word taking-out means sequentially takes out words stored in the addresses beginning with the block starting address of the word storing means and ending with an address short of the block limit address by using the starting address and the block limit address which are taken out from the block-starting address storing means with the block number used as the retrieving key. Finally, a word comparing means is provided for detecting a word similar to the input character string to a degree over a given value by the comparison of the words thus taken out with the input character string.

The SSR system: An open format event recording system with computerized transcription

Abstract: The SSR system is an event recording system that encodes the incidence, duration, coincidence, and sequence of entries in real time onto magnetic tape for subsequent high-speed transcription by computer. The keyboard is light weight and battery powered for field as well as for laboratory applications. A conservative encoding scheme employs phase encoding and multiplexing circuitry to sample the set of 48 alphanumeric and other characters 20 times per second. The sampling rate provides a time base that is independent of tape speed. The encoding signal is recorded on an audio tape recorder at 1–7/8 ips (inches per second). A supplementary voice record can be made on a parallel track. At transcription, a small computer decodes the data tape at 15 ips; 1 h of data is transcribed into a string of characters in 7 1/2 min and stored in binary form. A second program organizes the character string into a timed manuscript of lines. The character set and all character functions, e.g., the subset of characters that start lines, are entirely software defined. A completely open format and the flexibility of user-defined software grammars facilitate the entry of subjects, actions (both momentary and continuous), objects, and other contextual information in whatever form the user requires. The SSR system is described both as a system of ideas about the problems of encoding observations for computerized transcription and as it is currently embodied in a specific set of software and field-tested hardware. The rationale for each major aspect of the system is presented in detail from a user’s point of view.

Interproximal space tooth cleaner

Abstract: A variable diameter tooth cleaner formed by a plurality of elongate filaments to have a brush portion and a string portion with the string portion having two parts and with the brush portion being placed between the two parts. The string parts may be flexible or for spaces associated with fixed bridges may be formed with a rigid end extent for enabling insertion by pushing into the spaces.

Sequential classification of strings generated by SCFG's

Abstract: A sequential classification algorithm (SCA) for stochastic context-free languages is given. The algorithm is an extension of Earley's parsing algorithm for context-free languages. The SCA uses an optimum decision rule and a suboptimal stopping rule. The time bound is proportional ton 3 (n is the length of the string). A parametere* in the SCA allows an easy control over the probability of error. It is shown theoretically and experimentally that a considerable amount of processing time can be saved when using the SCA compared to the time required when using Earley's algorithm.

By-pass tool

Abstract: There is disclosed a tool which is connectible as part of a drill string and which is adapted, upon lifting of the drill string, to permit drilling fluid therein to by-pass a motor in the lower end of the string below the tool.

Model for interactive data base reference string

Abstract: A particularly simple Markov chain model for a reference string is described. The model, which is only slightly more complicated than the independent reference model, generates strings that have a locality property and that have a specified probability distribution of references over pages. Expressions are obtained for expected working-set size and expected working-set miss ratio. The model is used in an examination of the effect of grouping pages into blocks and in a discussion of the problem of evaluating the effect of changes in the size of the data base. Predictions of the model are shown to agree closely with observations of a string of data base references generated by an interactive data base system having a large number of concurrent users.

Strings for musical instruments

Abstract: A metal string for a fingerboard type stringed musical instrument has a core wire, or wires, and a first part of the length of the string is loaded in known manner whilst a second part of the length of the string remains non-loaded, the respective lengths of the loaded and non-loaded portions being such that, when the string is fitted to a musical instrument having two string supports such as the conventional "nut" and "bridge," the string may be arranged with the loaded portion supported by the nut and with the non-loaded portion supported by the bridge, but with the vibrating portion between the nut and bridge (the "speaking length" of the string) constituted substantially wholly by loaded string.

Apparatus and method for performing a desired operation at a specified location in a well

Abstract: An apparatus and method for performing a desired operation in a selected mandrel in a well. The apparatus includes a running assembly with selector stop means and operating tool means. The running assembly is run in the tubing string until the selector stop means positively locates it with respect to the selected mandrel. The operating tool means can then be manipulated to perform the desired operation in the selected mandrel. This abstract is neither intended to define the invention of the application which, of course, is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.

Reaction times in a task analogous to “same”-“different” judgment

Abstract: Subjects responded “yes” if two equal-length strings of letters contained a common letter in a common position; otherwise they responded “no.” Thus, the task was to judge whether all or not all of the letters in one string differed from the letter occupying the corresponding position in the other string. Conversely, in “same”-“different” judgment, the task is to judge whether all or not all of the letters in one string match the corresponding letter in the other string. Thus, common-letter judgment and “same”-“different” judgment are symmetrically related with “no” analogous to “same” and “yes” analogous to “different.” The response “same” is often faster than the response “different.” However, in the common-letter task, “no” was slower than “yes.” More specifically, both the “yes” and “no” reaction times were consistent with a serial self-terminating search. This is precisely what would be expected from Bamber’s (1969) two-process model.

Devices for use with stringed musical instruments

Abstract: A device for use in playing a stringed instrument comprises a base plate which is adapted to be fitted above the strings and which carries at least one pair of keys connected by a cross-bar by which both keys can be operated together to engage different strings or either key can be pressed against its own string only. There may also be other, individually operable keys.

The decision tree classifier - Design and potential

Abstract: A new classifier has been developed for the computerized analysis of remote sensor data. The decision tree classifier is essentially a maximum likelihood classifier using multistage decision logic. It is characterized by the fact that an unknown sample can be classified into a class using one or several decision functions in a successive manner. The classifier is applied to the analysis of data sensed by Landsat-1 over Kenosha Pass, Colorado. The classifier is illustrated by a tree diagram which for processing purposes is encoded as a string of symbols such that there is a unique one-to-one relationship between string and decision tree.

Vector extensions to LRLTRAN

Abstract: The CDC STAR-100 brings a new concept in computing to LLL. The STAR is a string(vector) - oriented machine that is most efficient when it performs the same operations on sequentially stored operands. This approach to computer design opens up new areas of problem-solving techniques. Some algorithms that are long and cumbersome on other machines can be easily and efficiently programmed on the STAR computer. The vector extensions described in this paper represent an attempt to expand LRLTRAN (a dialect of FORTRAN) into a useful computer language for the STAR. The additions will enable an LRLTRAN-language compiler to produce vector code and hence allow the programmer to access, via LRLTRAN, the powerful STAR hardware instructions.

Derivation languages and syntactical categories

Abstract: Derivations in unrestricted phrase structure grammars are represented in terms of a string called a derivation word. The derivation word gives a very compact representation of the canonical (leftmost) derivation. An algebra of derivation words is developed to give a concrete realization to the categorical treatment of derivations due to Hotz. In particular, derivation composition and juxtaposition are defined for derivation words, and effective techniques are given for obtaining the domain and codomain functions. All of the algorithms can be performed in linear time and space.

An algebraic model for string patterns

Abstract: of SNOBOL [Farber et al. 19641 and its descendant, SNOBOL4 ~Griswold et al. 19711, has found widespread appl~cation in a great variety of string manipulation problems. .—— Although SNOBOL4 is dominant in the field, other string manipulation languages have been developed, among them AXLE [Cohen and Wegstein 1965], PANON [di Forino 1968], and COMIT [Yngve 19721. Each of these languages provides facilities for the grouping, rearranging, inserting, deleting, sorting, testing, tagging, and counting of strings. Accordingly, they share a common set of design difficulties, characteristic of this class of languages.

Symbol string pattern recognition equipment

Abstract: A symbol string pattern recognition equipment for use in a pattern data processing system employs sequential logics to perform simultaneous comparison of respective symbol string patterns and standard symbol patterns. The equipment includes an external signal generating circuit for generating respective symbols constituting a symbol string pattern in the form of a string of binary-coded external signals. At least one internal signal generating circuit generates an internal signal upon initiation of the supply of the symbol string pattern. A plurality of sequential logic circuits are connected to the internal signal generating circuit and control the travelling paths of the internal signal. A gate circuit is connected between each of the sequential logic circuits and adapted to be turned on upon completion of the supply of the symbol string pattern. An external shift register is connected to the gate circuit, and a circuit for detecting the internal signal is connected to the external shift register.

An algorithm for finding the shortest terminal strings which can be produced from non-terminals in context-free grammars

Abstract: Properties of individual non-terminal symbols in context-free grammars are of interest in the fields of compiling and artificial intelligence. This paper describes an algorithm which will find, for all the non-terminal symbols in any context-free grammar, the shortest string which consists only of terminal symbols which can be produced from each non-terminal symbol by application of the rules of the grammar.

Method for selectively retrieving a plurality of well packers

Abstract: A method of operating a plurality of well packers in a borehole involves selectively retrieving one or more of the well packers on a single trip of the production string or a work string out of the borehole.

Forced serial processing of words and letter strings: A reexamination

Abstract: Words and nonword strings, three and seven letters long, were displayed serially (i.e., one letter at a time) or simultaneously, with or without a backward mask following display of each letter or string. Recognition of words, and of individual letters within words, was markedly impaired in the masked serial condition relative to the unmasked serial, unmasked simultaneous, and masked simultaneous conditions. Analogous differences were smaller or nonexistent for seven-letter nonwords; however, three-letter nonwords produced relatively “wordlike” data. Implications for the issue of spatially serial vs. parallel processing in word recognition are discussed.