Showing papers on "String (computer science) published in 1985"

Evidence Against the Context-Freeness of Natural Language

Abstract: In searching for universal constraints on the class of natural languages, linguists have investigated a number of formal properties, including that of context-freeness. Soon after Chomsky’s categorization of languages into his well-known hierarchy (Chomsky, 1963), the common conception of the context-free class of languages as a tool for describing natural languages was that it was too restrictive a class — interpreted strongly (as a way of characterizing structure sets) and even weakly (as a way of characterizing string sets).

Means for resolving ambiguities in text based upon character context

Abstract: A method of identifying an object within a set of object candidates includes the steps of: calculating the probability of occurrence of each member of a set of string candidates, wherein each string candidate contains one member of the set of object candidates, the calculating employing formulae using a method of groups and projections; and identifying one of the objects based on the calculated probability.

Combinatorial Algorithms on Words

Abstract: Open Problems in Stringology- 1 - String Matching- Efficient String Matching with Don't-care Patterns- Optimal Factor Transducers- Relating the Average-case Cost of the Brute force and the Knuth-Morris-Pratt String Matching Algorithm- Algorithms for Factorizing and Testing Subsemigroups- 2 - Subword Trees- The Myriad Virtues of Subword Trees- Efficient and Elegant Subword Tree Construction- 3 - Data Compression- Textual Substitution Techniques for Data Compression- Variations on a Theme by Ziv and Lempel- Compression of Two-dimensional Images- Optimal Parsing of Strings- Novel Compression of Sparse Bit Strings- 4 - Counting- The Use and Usefulness of Numeration Systems- Enumeration of Strings- Two Counting Problems Solved via String Encodings- Some Uses of the Mellin integral Transform in the Analysis of Algorithms- 5 - Periods and Other Regularities- Periodicities in Strings- Linear Time Recognition of Square free Strings- Discovering Repetitions in Strings- Some Decision Results on Nonrepetitive Words- 6 - Miscellaneous- On the Complexity of some Word Problems Which Arise in Testing the Security of Protocols- Code Properties and Derivatives of DOL Systems- Words over a Partially Commutative Alphabet- The Complexity of Two-way Pushdown Automata and Recursive Programs- On Context Free Grammars and Random Number Generation

Markov Source Modeling of Text Generation

Abstract: A language model is a conceptual device which, given a string of past words, provides an estimate of the probability that any given word from an allowed vocabulary will follow the string. In speech recognition, a language model is used to direct the hypothesis search for the sentence that was spoken. In fact, its probability assignments are a factor in evaluating the likelihood that any word string was uttered, and in ordering the word string hypotheses to be examined (1). Language models are also useful in text encoding for compression or transmission, in character recognition of printed or handwritten text, etc. Ideally, the probability assigned by a language model to any word should depend on the entire past sequence of words. However, it is practically impossible to implement such a dependence: 1) The probability estimate involved would have to be extracted from a giant sample of training text containing billions of words; 2) If the probabilities were extractable, sufficient space in computer memory could not be found to store them.

Linear Time Recognition of Squarefree Strings

Abstract: A square is an immediately repeated nonempty string, eg, aa, abab, abcabc This paper presents a new O(n log n) algorithm to determine whether a string of length n has a substring which is a square The algorithm is not as general as some previous algorithms for finding all squares [1,7,8,13], but it does have a simplicity which the others lack Also, for a fixed alphabet of size k, the algorithm can be improved by a factor of log k (n), yielding an O(n) algorithm for determining whether a string contains a square

Tubular member anchoring arrangement and method

Abstract: Apparatus releasably supported on a setting string responds to manipulation of the setting string to release therefrom and anchor to a tubular member. A member on the setting string is provided with a tubular member engaging arrangement which responds to further manipulation of the setting string to anchor the member in the tubular member. A disconnect is operable upon manipulation of the setting string to disconnect the setting string from the anchored member and a release arrangement enables the disconnected setting string to release the anchored apparatus from the tubular member.

Efficient variants of Huffman codes in high level languages

Abstract: Although it is well-known that Huffman Codes are optimal for text compression in a character-per-character encoding scheme, they are seldom used in practical situations since they require a bit-per-bit decoding algorithm, which has to be written in some assembly language, and will perform rather slowly. A number of methods are presented that avoid these difficulties. The decoding algorithms efficiently process the encoded string on a byte-per-byte basis, are faster than the original algorithm, and can be programmed in any high level language. This is achieved at the cost of storing some tables in the internal memory, but with no loss in the compression savings of the optimal Huffman codes. The internal memory space needed can be reduced either at the cost of increased processing time, or by using non-binary Huffman codes, which give sub-optimal compression. Experimental results for English and Hebrew text are also presented.

Discovering Repetitions in Strings

Abstract: There are many variants of problems involving string matchings. The basic problem is to determine whether a pattern string x appears as a (contiguous) substring of a text y, i.e. whether for some strings u, v, we have y= uxv. The classical string matching algorithm due to Knuth, Morris, Pratt [5] solves this problem in time linear in the length |y| of y. The KMP algorithm requires |x| auxiliary storage locations. Galil and Seiferas [3, 9] reduced the auxiliary storage requirements first to o(log|x|) and then to a constant number.

String comparator for searching for reference character string of arbitrary length

Abstract: A string comparator is provided for searching the address of a stored string having substantially the same content as that of an input reference string. This comparator comprises a memory including a number of memory cells arranged in a matrix form having a plurality of rows and a plurality of columns. Each string is stored in the memory in such a manner that the row position of each of the memory cells corresponds to the content of a stored string and the column position of each of the memory cells corresponds to the address of the stored string. A row selector is coupled to the memory for selecting one row of the memory cell matrix corresponding to the content of the input reference string to be compared, so that the content of the memory cells belonging to the row selected by the row selector is read out.

Pipe measurement, labeling and controls

Abstract: A combination of systems to measure the length of pipe sections and to label the pipe surface with machine readable labels. The combination also commits to memory the data and specifications read from the label or derived from correlative information already in memory. Summation of pipe joint data and specifications provide overall pipe string data. From the collective pipe string data, the reaction of the string to the input of physical forces can be predicted and evaluated.

Method and apparatus for running long tools into and out of a pressurized enclosure

Abstract: A method and apparatus for running long tools into an out of pressurized enclosures includes a tool stop assembled on an access pressure lock of the enclosure and which tool stop cooperates with a segmented tool string to allow sequential assembly, insertion, withdrawal and disassembly of the tool string into and out of the enclosure. The tool string is made up of a number of tool segments interconnected by coupler/spacer members of smaller diameter than the tool sections and of shorter length. The tool catcher acts upon the thinner sections of the coupler/spacer members to fixedly hold the tool string in place for subsequent assembly/disassembly without allowing any significant pressure change in said enclosure.

Inverse assembly method and apparatus

Abstract: An inverse assembly method for converting binary executable microprocessor code into corresponding assembly language mnemonics provides for the storage of all the possible binary codes and corresponding assembly language mnemonics in a plurality of tables set up in a decision tree form which corresponds to the format of a user document provided by the manufacturer of a target microprocessor. The instructions and data information contained within the executable code acquired from the taret microprocessor are distinguishably tagged prior to being stored in an acquisition memory. The code from the acquisition memory, in binary or hex form, indexes a primary table which contains a plurality of entries containing a binary value which may have a mask portion, each entry containing a plurality of actions having an optional string to be displayed, optional parameter masks and an optional table to call. The unmasked portion of the binary value is compared with the code from the acquisition memory and, if a match occurs, this entry is used for further processing, otherwise the comparison process moves on to the next entry in the table. Once a match is found a character string is displayed, parameter bits are picked off to be passed to another table, and another table is called within the decision tree. This continues until all actions are completed, including calls to additional tables which are similarly processed. After the processing of each called, or current, table is completed, a return to the calling table is made, and if there is no calling table then disassembly for the current code from the acquisition memory is completed. In like manner all the acquired executable code is processed to obtain the corresponding assembly language mnemonic.

Managing the integration of acquired operations

Abstract: Each year, U.S. corporations invest billions of dollars in mergers and acquisitions. Unfortunately, the resulting combinations all too often fail to produce the benefits envisioned by management. As a consequence, few corporations are able to boast an unblemished string of successful acquisitions. This article provides an overview of measures that can be taken to better assure the success of such transactions.

String tuner attachment

Abstract: A tuner device for a string instrument such as a guitar including a conventional tuning machine such as one incorporating a worm gear drive for initially tuning a string by controllably rotating the output shaft which has mounted thereon a peg on which a string is wound. The tuning machine is mounted on a support plate assembly which is selectively arcuately rockable through a small angle from its rest position to its operative or detuned position.

Piano string excitation

Abstract: Prediction of piano string motion is challenging for the theorist because the force from the hammer extends over a finite time. Abstract prescriptions for solving this problem with sequences of traveling waves become much more useful when a microcomputer can be assigned to generate all the proper terms and translate their total into graphical output. Sample results will be discussed for a program that includes hammer compliance and can handle any case where the hammer mass is not too much larger than the string mass. How to make adequate allowance for hammer nonlinearity and finite width, string stiffness, and bridge compliance will be considered, along with possible laboratory measurements that could clarify the application of this theory to piano hammer design.

Dual-purpose article

Abstract: A string secured at each end to a marginal edge of a rectangular towel. The string, when drawn upon, pulls on the opposing marginal edges of the towel to form, between the string and the towel, an opening to receive the head and neck of a wearer. VELCRO fasteners, adjacent the side opposed to the marginal edge, are used to secure the towel about the user to thereby form a robe.

Textual Substitution Techniques for Data Compression

Abstract: With many types of networks (e.g., distributed computing, electronic mail, etc.) communication channels are relatively slow. The ability to put large amounts of processing power on a single chip promises to make sophisticated data compression algorithms truly practical. A data encoding/decoding chip can be placed at the ends of every communication channel, with no computational overhead incurred by the communicating processes. Similarly, secondary storage space can be increased by hardware that (invisible to the user) performs data compression. For the purposes of this paper, data compression refers to transforming a string of characters to another (presumable shorter) string, from which it is possible to recover (exactly) the original string at some point later in time. This paper surveys research on data compression methods that employ textual substitution.

Optical character reader

Abstract: PURPOSE:To improve efficiency of read-out processing by recognizing characters necessary for read-out processing in a detected/cut off character string only by adding an underline in correspondence to read-out object characters on a document. CONSTITUTION:A reflecting light beam P is transmitted to an photoelectric converting part 10, and a character pattern obtained by photoelectrically converting the reflecting light beam P is outputted to a line buffer 11 in which character patterns for one line are stored. A row detecting/cutting off circuit 12 generates a concentration histogram in the line direction in the buffer 11. Thus the row detecting/cutting off circuit 12 detects/cuts off a character line. At the time of detecting/cutting the line, a low address to specify a character line is instructed to a control part 14. An underline detecting circuit 13 generates a concentration histogram in the string direction within the low address in the buffer 11 by control of the control part 14. A recognizing part 15 executes recognition processing in accordance with a standard pattern in a dictionary memory 16 set beforehand, and answeres are outputted to the control part 14.

Two counting problems solved via string encodings

Abstract: The common feature of the two problems presented in this paper is the use of bijective string encodings to solve counting questions. The first problem deals with a “natural” object — the size of the transitive closure of a random mapping. In the second problem certain contrived combinatorial objects are counted in two different ways in order to devise a new class of Abelian identities.

Method and apparatus for comparing strings using hash values

Abstract: To facilitate the comparison of strings in logic programming, a hash code is added to each string having a value that depends on the contents of the string. Typically, this hash code is made part of the header for the string along with a string identification number, a number specifying the length of the string and a bit specifying whether the string is a run time string or a compile time string.

Data communications analyzer

Abstract: Apparatus for comparing a stream of data characters with a predetermined string of test characters has an input device for receiving the stream of data characters and a main processor for generating the predetermined string of test characters. A hardware register receives the predetermined string of test characters from the main processor, and a comparator device compares the stream of data characters with the contents of the register device and generates a response in the event that a portion of the stream is identical to the string of test characters generated by the main processor. A second processor receives the response and sends a report to the main processor.

The Tower Hamlets Project

Abstract: ‘Project’ is something of a misnomer for the complicated string teaching organisation which now involves some thousand young string players, twenty ILEA schools in and around the Tower Hamlets area, and 35 qualified string teachers, mostly on a part-time basis. At no time in the early days was any such structure projected: it has grown up as a result of experience and considerable generosity on the part of the ILEA in allowing scope for experimentation and expansion.

Multiple string well packer

Abstract: A multiple well string packer of the type wherein the packer is lowered into a well bore on one of the well strings, and the one string hung off from the wellhead so that the packer may be set at a desired level therein, and wherein the packer, when unset, is retrieved from the well bore on the same string, the other string or strings being lowered into and raised from connection with the packer, when disposed at such level, separately of the one string.