Showing papers on "String (computer science) published in 1973"

Linear pattern matching algorithms

Abstract: In 1970, Knuth, Pratt, and Morris [1] showed how to do basic pattern matching in linear time. Related problems, such as those discussed in [4], have previously been solved by efficient but sub-optimal algorithms. In this paper, we introduce an interesting data structure called a bi-tree. A linear time algorithm for obtaining a compacted version of a bi-tree associated with a given string is presented. With this construction as the basic tool, we indicate how to solve several pattern matching problems, including some from [4] in linear time.

TOL systems and languages

Abstract: We discuss a family of systems and languages (called TOL) which have originally arisen from the study of mathematical models for the development of some biological organisms. From a formal language theory point of view, a TOL system is a rewriting system where at each step of a derivation every symbol in a string is rewritten in a context-free way, but different rewriting steps may use different sets of production rules and the language consists of all strings derivable from the single fixed string (the axiom). The family of TOL languages (as well as its different subfamilies considered here) is not closed with respect to usually considered operations; it is “incomparable” with context-free languages, but it is contained in the family of context-free programmed languages. TOL languages form an infinite hierarchy with respect to “natural” complexity measures introduced in this paper.

Drilling apparatus and adaptor assembly for such apparatus

Abstract: The invention relates to drilling apparatus having an inner drill string and a surrounding outer drill string, which strings can be advanced simultaneously. Instead of these strings being rigidly coupled for simultaneous advance under a rotary percussive action, the inner drill string is connected to a first adaptor which is slidable but non-rotatable in a second adaptor to which the outer drill string is connected so that when the first adaptor is rotatively and percussively driven, the second adaptor and its associated outer drill string are rotatively driven. Percussion is preferably transmitted to the bit of the outer drill string by arranging the bit of the inner string to strike the outer bit, but alternatively or additionally the first adaptor may hammer the second adaptor.

A formal theory of actions

Abstract: This paper presents a formal theory of actions which may serve as a foundation for different domains, such as theory of organization, theory of planning, etc. The basic idea underlying the construction is that actions may be concatenated into strings, by performing them one after another, and that not all strings of actions so obtained are physically feasible. This allows us to draw an analogy between the class of admissible strings and a language: actions play the role of words in a certain vocabulary, and the admissible strings of actions play the role of sentences. One may therefore speak of a language of actions, characteristic for a given situation, and analyse it by means of mathematical linguistics. Moreover, a string of actions leads to certain outcomes. If one considers only those outcomes which are inherently connected with this string, i.e., occur whenever this string is performed, one may enrich the language of actions with a semantic structure: the well determined outcomes of a given string of actions play very much the same role as meanings of sentences. The above linguistic intuitions apply to the case of linear concatenations, where simultaneous actions are excluded; thus, the main, but not the only one, interpretation is in terms of actions of a single person. One may, however, consider also simultaneous strings of actions, for which the interpretation is in terms of team actions. In this case, some methods of mathematical linguistics are still applicable, leading to formal explication of such concepts as cooperation, blocking, etc.

Stringed musical instrument with electronic time division multiplexing circuitry

Abstract: A musical instrument has electrically conductive strings and a fingerboard with an array of fingerpads each serving as an electrical contact with which each of the strings are selectively connected as they are manually adjusted in length in selecting musical notes to be played when the string is vibrated. For each string there is a separate pick-up device for indicating when the string is vibrating. Circuitry including time-division multiplexing circuitry and gating circuitry controlled by the pick-up devices provide electrical signals representing notes related either directly or preferably harmonically to those played on the instrument.

String system for a game racket

Abstract: A string system for rapidly stringing game racket frames ultilizing an improved string suspension system consisting of a plurality of openly accessible string support elements coacting with and spaced around the inner circumference of the racket frame and a prewoven net consisting of a plurality of interwoven longitudinal and latitudinal runs of strings, wherein the longitudinal and latitudinal strings, respectively, upon completing a run of predetermined length, each form a loop and begin another run of predetermined length in the opposite but predominantly parallel direction to and spaced apart from the preceeding run. This is continued with both the longitudinal and latitudinal strings, alternately interweaving the longitudinal and latitudinal strings until a woven net of predetermined size and shape is achieved with respect to the game racket frame to be strung. The loops of the prewoven net are attached to and supported by corresponding openly accessible string support elements of the string suspension system thereby combining the stringing and tensioning operations.

Intonation guide for player of string instrument

Abstract: Intonation guide providing a signal element, and a circuit therefor, including at least one normally open switch with a tab mounted on the fingerboard of a string instrument and located within pressure reach of a player''s finger when fingering a string correctly for playing a particular note at correct pitch, with the tab, when pressure-activated by the player''s finger, closing the switch for a signal emission.

A comparative analysis of several models of the ventricular depolarisation : introduction of a string model

Abstract: Introduction The objective of the string model page 1 2 4 2 The physiological background of the string model 5 3 Evaluation of the field potential 9 4 Relative importance of mUltipoles 13 5 Comparison with a multiple dipole model 16 6 The effect of a spherical boundary 19 7 Deviations of the one-dipole, the dipole and quadrupole, and the six dipole model in comparison with the string model 20 8 Surface potentials 24 9 Intrinsic components 26 10 Conclusions and future developments 30 Acknowledgement 32 Literature 33 General notations and list of important variables Tables and Figures 36 38

A Necessary and Sufficient Condition for Chomsky-Productions Over Partially Ordered Symbol Sets

Abstract: The concept of Chomsky-grammar is generalized to multi-dimensional arrangement of symbols using multi-graphs the vertices and edges of which are labelled. The question arises in what cases productions preserve partial ordering. Vie give a necessary and sufficient condition for this. Furthermore, it is shown that context-free string grammars are a special case, but this is not true for context-sensitive grammars. Context-sensitive grammars in our definition are related to scattered context grammars.

Effects of bars and blanks on recognition of words and nonwords embedded in a row of letters

Abstract: Solid bars or blank spaces placed before, after, or on both sides of a pronounceable four-letter string embedded in a longer string of letters facilitated recognition of the embedded string. This effect was equal whether bar or blanks were used, and whether the embedded string was a word or a pronounceable nonword. The effect of bars or blanks on pronounceable strings was interpreted in terms of a multiletter processing operation.

A language-oriented instruction set for the BALM language

Abstract: The availability of microprogramming has increased interest in the design of instruction sets which are oriented towards particular higher-level languages (see (1), for example). We will refer to these as language-oriented instruction sets (or LOISs). In this paper we give a formal definition of a LOIS for the extendable language BALM. This LOIS, which we call MBALM, is used as the basis of the implementation of the current version of the language, BALM4. We will also compare two implementations of the MBALM instruction set, and outline briefly our experiences with them.The external description of BALM4 is given in detail elsewhere (2,3). Briefly, it is an extendable language with an Algol-like syntax and data-types integer, real, logical, string, pair (list), vector, identifier, procedure, and label. Type information is carried with all data-objects, and run-time type testing and conversion is done when necessary. Garbage collection and a run-time compiler are significant attributes of the system. Outlined below are some of the properties of the implementation, which was designed initially for reasons of simplicity and flexibility, but which illustrate some of the advantages of a LOIS-based system.

Design considerations for cryptography

Abstract: Enciphering data can protect the transmission of information against unauthorized observers. One way of doing this when data is transmitted in binary form is to add random numbers to the data. If the string of random numbers is never repeated, the scheme is unbreakable. p. 398.

Nonfiltering and Local-Filtering Transformational Grammars

Abstract: A transformational grammar delimits a set of grammatical sentences by virtue of containing (a) a base component which generates a set of base Phrase-markers (labeled trees or labeled bracketings), (b) a transformational component which maps these into derived Phrase-markers and (c) filter predicates which pose a further admissibility condition on the latter Phrase-markers. A string x is grammatical according to such a grammar if there is a Phrase-marker generated by the base component which is mapped by the transformational component to a Phrase-marker satisfying all the filter predicates and having x as its terminal string. Thus all these three parts of a grammar play a role in specifying what strings are grammatical — the base component by determining what Phrase-markers will be available for transformations to operate on, the transformational component by converting these inputs into derived Phrase-markers, the filter predicates by excluding certain of these outputs as inadmissible.

Selective hydrostatically set parallel string packer

Abstract: A hydraulically or hydrostatically set parallel string well packer to be used in conjunction with one or more hydraulically set well packers therebelow, all of the well packers being adapted for lowering in a well bore on a first or long tubular string to desired setting locations and selectively settable hydraulically in packed-off condition at each setting point without longitudinal movement of the long string, whereupon a second or short tubular string can be lowered in the well bore parallel to the first tubular string and appropriately related to the parallel string packer.

Data structures and accessing in data-base systems: III data representations and the data independent accessing model

Abstract: Presented is the Data Independent Accessing Model (DIAM)--a complete model for the representing, storing, and retrieving of structured information. DIAM is a hierarchy of models formed by the Entity Set Model and three lower modeling levels--the String Model, the Encoding Model, and the Physical Device Level Model.

String tension measuring device

Abstract: A device for measuring the tension of relatively taut strings of tennis rackets or the like The device comprises a single piece of material formed to have a handle, a string engaging portion, and a resilient portion joining the two The string engaging portion bears a calibrated scale and a reference mark The handle includes an index mark positioned such that when the handle is twisted relative to the engaging portion as the latter is secured to a string, measurement of tension is indicated on the scale by the index mark when the reference mark is in alignment with the string being tested

Guitar stringing tools

Abstract: A hand tool or pliers for stringing a guitar or other string instruments, using peg and string arrangements or the like, is disclosed The hand tool includes a pair of handles terminating in a removable jaw fabricated of spring steel wires which extend outwardly and cooperate to form a narrow tip thereby The hand tool further includes a first padded portion adapted to grasp the strings when stretching them and a second beveled portion adapted to cut the string as needed

On Harrison's substring testing technique

Abstract: This note comments on a technique by Malcolm Harrison [1] that tests whether a given string of characters, S1, is a substring of another string of characters, S2. This technique first transforms S2 into the set consisting of all the smaller fixed size substrings of length k and then hashes each of these segments into the m positions of a computer “word”; the bit corresponding to a position in this word is turned on if at least one segment is hashed onto it; else it is zero. The test is based on the observation that the same procedure applied to an arbitrary substring of the first string will not turn on any new bits. In the following we shall assume that S1 and S2 are decomposed into l1 and l2 segments respectively.

The Design of a Versatile Line Manipulator.

Abstract: : 81RADCTR-73-292*Parallel processors, *Parallel processing, Algorithms, Logic circuits, Shift registers, Mathematical logic*Associative processorsA versatile line manipulator which is capable of achieving various data manipulating functions is described. This manipulator design is particularly attractive in applications requiring extensive spacing functions and/or operations for non 2's power set or string sizes and replications. The basic circuit has an N-by-N array construction and can be implemented with one circuit type. The flexibility of such a construction is demonstrated and extensive illustrations of implementing basic VLM instructions are given. (Author)

Picture Analysis by Graph Transformation

Abstract: Thesis. A methodology to analyze the pictorial information represented in a map-like image, and further name the objects most likely present in the scene based on the universe known to the system is developed. In contrast to conventional string language sentences which are formed by concatenating the primitives (symbols) in a string according to the language grammar, the pictorial sentences are basically formed of primitives which are located in a twodimensional (or three-dimensional) space with much richer relational properties than simple adjacency. The possibility of describing the structural information of pictures as syntactical rules, employing a rich class of relations, was examined. The gnaphs are known to be extremely convenient and flexible to represent this kind of information. By expressing the syntactical properties of one class of pictures as a collection of graphs, it was shown that algorithms can be easily developed to parse objects or collections of objects which belong to this class. Further, this methodology is flexible enough to recognize incomplete objects, and has learning capabilities through adding and modifying the rules of the system. In addition, it was shown that a complete description of an object as a collection of gnaphs can be easily modified (rotated) tomore » enable the system to recognize different projections of the object. (auth)« less

Blanks for mechanical working - mounted on metal string at fixed intervals

Abstract: Metal shapes for further mechanical working are held together on a metal "string" at fixed intervals. The working may be a forging, rolling, pressing, drawing, or stamping operation and may be an intermediate or a finishing operation.

The Dynamic Creation And Modification of Heuristics in a Learning Program

Abstract: POLY FACT is a learning program that attempts to factor multivariable polynomials. The program has been successful in factoring polynomials (in simplified form) with a maximum of 84 terms, each term consisting of as many as five variables and a maximum degree of 67. The complexity of this learning task placed unusual requirements on the representation of heuristics. By using the first-order predicate calculus notation, we enable the creation and modification of heuristics dynamically during program execution. Constraints on the creation process are implemented in a series of tables by which one can alter the flexibility given to the program. Execution of heuristics begins with a translation of the predicate calculus representation to a reverse Polish string, followed by the interpretive evaluation of the Polish string. A general procedure for developing and implementing the predicate calculus representation is suggested.

From String Stories to Satellites: Portrayal of the Native Alaskan in Literature and Folklore

Abstract: Mrs. Hana Kangas earned her B.Ed. degree at the University of Alaska in 1940, her M.Ed. in 1967. In the twenty-seven-year interim this half-Eskimo woman raised a family and taught school. She vividly recalls sitting on the floor of the family barabara in the Arctic and watching the Eskimo string storytellers. Weaving a loop of sinew or cord on their hands into various figures reminiscent of the cat's cradle familiar to American folkways, they told the traditional beliefs, practices, and tales of the Eskimo people as they made the string figures. Even today, other Eskimo students relate similar experiences of communication enhanced by figures drawn into the earth during the telling with story knives. Some of these knives are intricately carved ivory instruments several inches long, which have been passed down from one generation to the next. Other instruments are simply table knives or nails that will scratch a fairly legible illustration into the earth to help more fully communicate the narrator's story. At the same time they employ these ancient means of communication among a people whose language only now is being developed into written form, native Alaskan storytellers today practice their art and reach larger audiences than ever by means of satellite communication. Through the auspices of the Fairbanks North Star Borough Library, the studios of the Lfniversity of Alaska's KUAC-FM radio station and the ATS-I satellite each week broadcast tales contributed by native storytellers to villages virtually throughout the 586,400-square-mile state. Such activity, coupled with an accelerating movement to publish native folklore, gives solid assurance that this important twenty-five percent segment of Alaska's population will at last receive its proper literary due, which, in rum, will lead to further political and social recognition. More important these efforts enable natives to carry their heritage across the multi-cultural bridges to understanding. The native Alaskan deserves a new, more accurate \"image\" than that generally projected in the past, particularly from the Gold Rush era of 1898 to about the mid-1920s, by Anglo-American authors who did have a written language and printing processes at their disposal. The traditional stereotypes which usually emerge in the works of the known poets, short story writers, and novelists follow to a great degree the precedent set in the anonymously composed, widely published \"Kobuk Maiden,\" which portrays the Eskimo

A “Shiplike” string instrument from West Africa*

Abstract: (1973). A “Shiplike” string instrument from West Africa. Ethnos: Vol. 38, No. 1-4, pp. 43-56.