Showing papers on "String (computer science) published in 1980"

Type Classification of Fingerprints: A Syntactic Approach

Abstract: A fingerprint classification procedure using a computer is described. It classifies the prints into one of ten defined types. The procedure is implemented using PICAP (picture array processor). The picture processing system includes a TV camera input and a special picture processor. The first part of the procedure is a transformation of the original print to a sampling matrix, where the dominant direction of the ridges for each subpicture is indicated. After smoothing, the lines in this pattern are traced out and converted to strings of symbols. Finally, a syntactic approach is adopted to make the type classification based on this string of symbols.

Application of dynamic time warping to connected digit recognition

Abstract: A connected digit recognizer is proposed in which a set of isolated word templates is used as reference patterns and an unconstrained dynamic time warping (DTW) algorithm is used to literally "spot" the digits in the string. Segmentation boundaries between digits are obtained as the termination point of the dynamic path from the previous time warp. A region around the boundary is searched for the optimum starting point for the succeeding digit. At each stage the recognizer keeps track of a set of candidate digit strings for each test string. The string with the smallest accumulated distance is used as the preliminary string estimate. To help improve the recognition accuracy, two "post-correction" techniques were applied to the entire set of hypothesized digit strings. One technique creates a reference string by concatenating reference contours of the digits of the string, and comparing this to the test string using a constrained dynamic time warping algorithm. The second technique performs a similar comparison using voiced-unvoiced-silence contours instead of the measured features. Small but consistent improvements in recognition accuracy have been obtained using these techniques for both speaker-trained and speaker-independent systems with digit strings recorded over dialed-up telephone lines. For variable length digit strings of from 2 to 5 digits (where the recognizer was not told the length of the string), word error rates of about 2-3 percent and string error rates on the order of 8 percent were obtained for both speaker-dependent and speaker-independent systems.

A Correct Preprocessing Algorithm for Boyer–Moore String-Searching

Abstract: We present the correction to Knuth’s algorithm [2] for computing the table of pattern shifts later used in the Boyer–Moore algorithm for pattern matching.

A New Proof of the Linearity of the Boyer-Moore String Searching Algorithm

Abstract: The Boyer-Moore algorithm searches for all occurrences of a specified string, the pattern, in another string, the text. We study the combinatorial structure of periodic strings and use these results to derive a new proof of the linearity of the Boyer-Moore algorithm in the worst case. Our proof reduces the previously best known bound of $7n$ to $4n$, where n is the length of the text.

Efficient LL(1) error correction and recovery using only insertions

Abstract: An LL(1)-based error-corrector which operates by insertion-only is studied. The corrector is able to correct and parse any input string. It is efficient (linear in space and time requirements) and chooses least-cost insertions (as defined by the user) in correcting syntax errors. Moreover, the error-corrector can be generated automatically from the grammar and a table of terminal symbol insertion costs. This method is also very well suited for use as an automatic error-recovery technique in LL(1) parsers. The class of LL(1) grammars correctable by this method contains (with minor modifications) grammars used to specify most common programming languages. Preliminary results suggest that this method can be used to advantage in LL(1)-driven compilers.

Saving Space in Fast String-Matching

Abstract: The string-matching problem is to find all instances (as contiguous substrings) of a “pattern” character string x in a longer “text" string ”. The naive algorithm, trying the pattern from scratch starting at each successive text position, requires only a fixed number of auxiliary storage locations but time proportional to $|x|\cdot|Y|$ (worst case). On the other hand, the fast algorithm of Knuth, Morris, and Pratt requires only time proportional to $|Y|$ but extra space proportional to $|x|$ (every case). Algorithms described in this paper reduce the extra space used by the Knuth–Morris–Pratt algorithm down to $O(\log |x|)$, and the time for the naive algorithm down to $O(|x|^\varepsilon |y|)$ for any fixed $\varepsilon > 0$. Also described are implementations on two-way multihead finite automata and multitape Turing machines.

Repeating the target neither speeds nor slows its detection: Evidence for independent channels in letter processing

Abstract: A target letter at a predesignated location typically is identified less readily when extraneous letters are added to the display. This disruption has been attributed to lateral interference via interactive or inhibitory channels or to attempts to encode the string as a unit. In the present study, subjects saw a single letter (e.g., B), a repeated-letter string (e.g., BBBB), or an extraneous-letters string (e.g., BCLD) and had to decide whether the leftmost letter in the string matched a target letter. Since trials were blocked by string type, letter position did not have to be discriminated on repeated-letter trials, nor was response competition present on those trials. With normal letter spacing, RT was virtually the same on repeated-letter trials as on single-letter trials. (Increasing the letter spacing in Experiment 3 did produce a slight, but nonsignificant, 22-msec increment on the repeated-letter trials.) The results indicate that individual letters are perceived as such just as well when presented in a group as when presented individually and thus provide support for the parallel, independent-channels model.

Spelled word recognizer

Abstract: A string of input characters is recognized as one of a plurality of reference sets which are stored in predetermined groups. A set of signals representative of the correspondence of the input characters to the reference characters is generated. The input character string is identified responsive to the character correspondence signals. The character string identification comprises forming a set of signals each representative of the correspondence of the input character string to one of the predetermined groups responsive to the character correspondence signals. Jointly responsive to the character correspondence signals, the reference character sets and the group correspondence signals, the reference set that most closely corresponds to the input character string is selected.

Resonant acoustic transducer and driver system for a well drilling string communication system

Abstract: The acoustic data communication system includes an acoustic transmitter and receiver wherein low frequency acoustic waves, propagating in relatively loss free manner in well drilling string piping, are efficiently coupled to the drill string and propagate at levels competitive with the levels of noise generated by drilling machinery also present in the drill string. The transmitting transducer incorporates a mass-spring piezoelectric transmitter and amplifier combination that permits self-oscillating resonant operation in the desired low frequency range.

Parsing for structural editors

Abstract: We present techniques that enable the construction of an algorithm capable of re-parsing a string after another string has been inserted into it. Let M be the minimal, under certain restrictions, number of changes which must be made to the parse tree to reflect the insertions. Then the algorithm we present should work in no more time than M times a log factor of the height of the parse tree. The grammars we allow include all LR(1) grammars.

How to Design and Teach a Successful School String and Orchestra Program: By Jacquelyn A. Dillon and Casimer B. Kriechbaum, Jr. San Diego: Kjos West, 1978. 288 pp. Photographs, illustrations, music examples, index. Hard cover, $11.95

Abstract: This book is a welcome addition to the growing number of recent publications dealing with public school string and orchestra programs. It was designed to fill the need for a method of large, heterogeneous class instruction and an analysis of organizational requirements and administrative concerns for comprehensive string programs. Through clear writing and superb organization, Dillon and Kriechbaum have succeeded in their stated goal of making the book "so pragmatic and detailed that any music teacher with the desire to learn can take it, follow the 'recipe,' and obtain excellent results even if they have not had the benefit of an extensive background in string performance." Little of the material contained in the book is original. String specialists will recognize influences from many string teaching schools of thought. It is this eclectic approach, however, that makes the book so valuable. Beginning teachers or nonstring specialists will appreciate the methods advocated by the authors. Experienced string teachers will value it as a compendium of successful pedagogical ideas that come from many sources. Dillon and Kriechbaum have organized the book in three general sections: "Organization of an Orchestra Program," "Teaching an Orchestra Program," and "Sustaining the Orchestra Program." Each section is further divided into appropriate chapters and subchapters. One of the most attractive features of the book is the use of differing styles of type to highlight the subject matter covered in a specific section. Not only does this create a handsome format, but it also simplifies the problem of finding desired topics. Part one, "Organization of an Orchestra Program," contains basic information on scheduling, equipment, budgeting, and recruiting procedures. Included in this section is an excellent discussion of proper instrument adjustments that should be taken care of quickly by the teacher. An illustrated discussion dealing with the matching of hand shapes with specific stringed instruments when recruiting young players will be advantageous reading for those not familiar with this concept. The section dealing with the rationale for establishing string programs (which presumably would be presented to superintendents or school boards for their consideration) is not, however, as compelling as one would hope. Certainly the fact that new string programs help, rather than hurt, existing band programs is amply documented by the authors. However, such traditional selling points as the uniqueness of the orchestral timbre and its exclusivity as the medium for the greatest quantity of instrumental music in the Western tradition are given short shrift. The major portion of the book exists in the second section, "Teaching an Orchestra Program." Specific principles of teaching, objecI Music Therapy

High-performance raster graphics for microcomputer systems

Abstract: A frame buffer architecture is presented that reduces the overhead of frame buffer updating by three means. First, the bit-map memory is (x,y) addressable, whereby a string of pixels can be accesse...

Segmentation system and method for optical character scanning

Abstract: A segmentation method and system for detecting intercharacter boundaries for a digital representation of a string of two or more characters extending in a first (X) direction. The digital representation has the form of an m x n array of bits, each being representative of a characteristic (such as optical reflectivity) of a correspondingly positioned picture element (pixel) in an image of the string of characters. A serpentine processor determines a succession of values of interest per swath in the array. A decision network processes the succession of values determined by the serpentine processor to identify a nominal boundary where segmentation is to occur. A separation processor performs the segmentation by associating the various bits representative of black pixels near the nominal intercharacter boundary with either the character to the left or the character to the right of that nominal boundary .

Apparatus to pump multiple wells

Abstract: A pumping unit pumps two wells, simultaneously, to save energy and space, weight of one rod string offsetting weight of the other string.

Stringed musical instrument having a bridge secured to and translatable along a string

Abstract: A stringed musical instrument having a plurality of strings stretched over the sounding board of a sounding box includes a corresponding bridge for each string. Each bridge rests on the sounding board and may be translated along the corresponding string to thereby change the functional vibrating length of the string and hence change the pitch of the musical tone produced when the string is set into vibration. Each string passes through a bore extending through the corresponding bridge so that the bridge does not disengage from the corresponding string (and possibly become misplaced or lost) when the bridge is translated, when the string is in a non-stretched condition, or when the instrument is jolted.

Auxiliary unit for book retrieval

Abstract: PURPOSE:To shorten character retrieval time in a dictionary by providing a data bank where entry words and their pages in a book are stored correspondingly and then by processing a string of characters inputted through key operations by a data processor to display pages. CONSTITUTION:Data bank 7 where entry words and their pages in a dictionary are stored correspondingly is contained in cartridge 8. Once the initial alphabet character of an entry word is inputted by key input unit 6, corresponding characters are displayed and CPU1 of data processor 3 extracts the smallest page of corresponding characters and then displays it on display unit 4b according to program 2. With the 2nd character inputted, the smallest page of corresponding characters is displayed on display unit 4. In this way, characters are sequentially inputted to extract corresponding pages, but when a string of characters for determination of the page have been inputted in this process, communicator 5 informs that following input operation is unneeded. When the dictionary is changed, the corresponding cartridge is replaced to perform retrieval in the same way.

Learn to Play on Sitar

Abstract: Teaches you the elements of music and the basics of learning the sitar, an immensely popular Indian string instrument.

Format input device

Abstract: PURPOSE:To enable automatic discrimination and classification, by calculating the position and size of format short area on the two dimensional picture and assigning the discriminating character code string to each area, in the input device of assigned format. CONSTITUTION:From the two dimensional picture data obtained from the picture input device 1, rectangular regions C1-Cn are cut out at the character recognizer 2 for character recognition, and the character rectangular regions S1-Sk including the character code of specific types are picked up at the character rectangular region calculator 3, and the relation of position among the format rectangular regions R1- Rk obtained from the format rectangular region calculator 4 and the character rectangular regions S1-Sk is calculated, and the character code string included in the character rectangular regions S1-Sk corresponded to the format rectangular regions R1-Rk is assigned as the discrimination code.

Systems for landing wire line tools at selected levels within a well tubing string

Abstract: There is disclosed, for use in a system for landing wire line "no go" tools at selected levels within a tubing string, a landing nipple connectible in the tubing string and in which either a top or a bottom "no go" tool may be landed.

Parsing for Structural Editors (Extended Abstract)

Abstract: We present techniques that enable the con­ struction of an algorithm capable of re-parsing a string after another string has been inserted into it. Let M be the minimal, under certain restrictions, number of changes which must be made to the parse tree to reflect the insertions. Then the algorithm we present should work in no more time than M times a log factor of the height of the parse tree. The grammars we allow in­ clude all LR(l) grammars.

Microcomputer‐generated graphic displays as an aid in string indexing

Abstract: Error rates in indexing using string index languages such as NEPHIS might be reduced at relatively low cost by having the indexer enter strings via a microcomputer system which could provide simple validation, and feedback in the form of graphic displays of concept links.