Showing papers on "Character (mathematics) published in 1979"

Recipient and message authentication method and system

Abstract: The specification discloses a system and method for authenticating a message recipient prior to transmission of a message and for authenticating the message content after receipt of the message. A randomized character or character sequence is initially enciphered at the authenticator station and stored. The enciphered character is transmitted to the message recipient. The enciphered character is deciphered by the message recipient to reproduce the randomized character. The randomized character is reenciphered by the message recipient and transmitted back to the authenticator station. The reenciphered character is deciphered and the stored randomized character is compared with the deciphered character. The message recipient is authenticated if the stored randomized character exactly compares with the deciphered character. In order to authenticate the message after receipt, polynomial block check characters are accumulated from the message. The block check characters are enciphered according to a predetermined enciphering scheme and transmitted to a remote location, along with the message. The message is received at the remote location and polynomial block check characters are accumulated in response to the received message. Enciphered block check characters are received and deciphered according to the reverse of the predetermined enciphering scheme. The accumulated block check characters are compared with the deciphered block check characters and the message is authenticated if the compared characters are the same.

Evidence for ecological character displacement in western american catostomid fishes.

Abstract: Much of recent ecological theory rests on the assumption that the primary factor responsible for the organization of natural communities, particularly of animals, is interspecific competition (e.g., MacArthur, 1972; Schoener, 1975). The validity of this assumption depends almost exclusively on inference drawn from observational evidence of two types. Morphological changes in the form of ecological character displacement (Brown and Wilson, 1959; Grant, 1972) and niche shifts correlated with geographic variation in the number or density of closely related species are generally considered the strongest available evidence for the importance of interspecific competition (MacArthur, 1972; Cody, 1974; Schoener, 1974, 1975). Grant (1972, 1975) defines ecological character displacement to be "the process by which a morphological character state of a species changes under natural selection arising from the presence, in the same environment, of one or more species similar to it ecologically . . . ." By this definition Grant would include both character convergence and divergence but would exclude cases of changes in character state due to the related process of character release. It seems clear that the interspecific interaction implicit in Grant's (1972, 1975) definition of ecological character displacement is competition. Furthermore, this causal relationship must be demonstrated if ecological character displacement is to be used as observational evidence for the occurrence of interspecific competition. Therefore, we define competitive character displacement to be a change of character state in a population that is due to natural selection arising as a result of competition with individuals of another population in the same environment. The characters may be morphological, ecological, behavioral, or physiological and the change may be either divergent or convergent. By divergent competitive character displacement we mean that a character state of a population in ecological sympatry (=syntopy, Rivas, 1964) exhibits greater difference than is the case when allopatric populations are contrasted, and that this effect can be attributed to sympatry. If the contrast of allopatric and sympatric populations reveals that the character states of the two populations are more similar in areas of sympatry than in areas of allopatry and if this effect can be attributed to competition, then the situation is one of convergent character displacement. Ecological theory predicts those situations in which convergent or divergent displacement would be expected (MacArthur and Levins, 1964, 1967; MacArthur and Wilson, 1967; Schoener, 1969a, 1969b, 1970; MacArthur, 1972). In all of these models the selection responsible for the character state change or niche shift arises as a result of interspecific competition. Grant (1972) in his critical review of the evidence for ecological character displacement, concluded that "the evidence for the ecological aspect of morphological character displacement is weak" and that "the detection of character displacement in its ecological aspect, particularly in mainland regions, will require a level of detail that has so far not been produced in a single study. " The weakness of the available evidence for competitive character displacement lies in the difficulty of establishing unambiguously that the character state of

On-line pattern recognition system for hand-written characters

Abstract: A pattern recognition system operating on an on-line basis for hand-written characters, in particular for hand-written Chinese characters comprises a character input unit for providing the coordinates of a plurality of points on the strokes of a written input character, a classification unit for classifying the input characters to the first group having equal to or less than three strokes, and the second group having equal to or more than four strokes, an approximate unit for providing a plurality of feature points to each of strokes, the number of strokes being six for each stroke in the first group of characters and three for each stroke in the second group of characters, a pattern difference calculator for providing the sum of the length between the feature points of the input character and those of the reference characters which are stored in the reference pattern storage, and a minimum difference detector for determining the minimum length among the pattern differences thus calculated. The input character is recognized to be the same as the reference character which provides said minimum length.

Optical character recognition based on nonredundant correlation measurements.

Abstract: The essence of character recognition is a comparison between the unknown character and a set of reference patterns. Usually, these reference patterns are all possible characters themselves, the whole alphabet in the case of letter characters. Obviously, N analog measurements are highly redundant, since only K = log2N binary decisions are enough to identify one out of N characters. Therefore, we devised K reference patterns accordingly. These patterns, called principal components, are found by digital image processing, but used in an optical analog computer. We will explain the concept of principal components, and we will describe experiments with several optical character recognition systems, based on this concept.

Method and apparatus for character generation

Abstract: Generation of a character code for an alphabetic character is performed by depressing at least two keys in a sequence. The code is generated when the last key is depressed and the other keys in the sequence still are pressed, or when all keys in the sequence are released. Numerical character codes are generated by depressing only one key per character. A logic and storage means is provided having a number of registers, code converting tables and control circuits for storing the history of depressed keys and for generating character codes.

High-speed term searcher

Abstract: A method and apparatus for high-speed searching of a byte stream for predetermined words or terms. More particularly, the present invention is directed to a method and apparatus for use in combination with a data source supplying a stream of binary signals defining both the identities of alphanumeric characters occurring in an ordered sequence and the position of each such character within a character group for detecting the occurrence of a particularly ordered group of R characters. The apparatus preferably includes a search memory means comprised of multiple (N) sets of R storage locations each of which includes S bit stages, each bit stage being capable of storing a "1" or "0" state. R represents the number of characters within a character group and S represents the number of different characters that can be identified. Each of the R storage locations may store one or more "0" bits, the position of each "0" bit identifying a particular character. A first decoding means is provided responsive to the position within a character group of each character defined by the binary signals for addressing a corresponding one of the R locations. A second decoding means is provided responsive to the identity of each character defined by the binary signals for addressing a particular one of the S bit stages within the addressed location. The addressing of a stage storing a "1" generates a word mismatch signal.

The duality operation in the character ring of a finite Chevalley group

Abstract: It is possible (as in [4] ) to define a duality operation f —• f * in the ring of virtual characters of an arbitrary finite group with a split (B, 7V)-pair of characteristic p. Such a group arises as the fixed points under a Frobenius map of a connected reductive algebraic group, defined over a finite field [1]. This paper contains statements of several general properties of the duality map f —• f * and two related operations (see §§2 and 4). The duality map f —• f * generalizes the construction in [2] of the Steinberg character, and interacts well with the organization of the characters from the point of view of cuspidal characters (§6). It is hoped that there is also a useful interaction with the Deligne-Lusztig virtual characters R^O. Partial results have been obtained in this direction (§5). Detailed proofs will appear elsewhere.

Variable size dot matrix character generator in which a height signal and an aspect ratio signal actuate the same

Abstract: A variable size and position character generator is described for use with a cathode ray tube raster scanning system to display characters as matrices of dots. The keyboard includes controls for permitting a user to select a particular height, aspect ratio and baseline for each character selected to be displayed. A unique character address signal is developed for each such selected character and serves to identify a unique, fixed size dot matrix for the selected character which is stored in a first read-only memory. A character converter, in the form of a second read-only memory, receives the selected height, aspect ratio and baseline information signals along with normal scan line counter signals and modifies the latter to develop scan control signals that are fed to the first read-only memory for controlling the height and position of the character selected to be displayed. The width of the character is also controlled by a dot rate selection signal developed in the character converter memory, which permits selection of one of a plurality of clock rates whose signals are then utilized to read out the contents of a parallel-to serial shift register that stores the individual dot signals for a given scan line segment.

Character generating method and apparatus

Abstract: A font storage system for use in a typesetter having an electronically controlled character imaging device. The storage system, which preferably includes a floppy disk, has digital information stored thereon defining each character to be typeset by at least two outlines on a normalized X-Y grid. The digital information defining each character includes (1) digital numbers defining the X and Y coordinates of the initial start points of the outline and (2) digital numbers defining a plurality of straight line vectors extending successively along the character outlines. Each vector has a first digital number representing the X coordinate distance and a second digital number representing the Y coordinate distance from one end of the vector to the other.

Optical character recognition using baseline information

Abstract: An Optical Character Recognition (OCR) system for printed characters uses information about baseline location to assist in registration, segmentation, recognition and the separation of underscoring. Selected ones of the sensor elements in the OCR scanning array are identified as defining a baseline searching window and the outputs of these selected elements are utilized to detect baseline information for each character or group of characters in a printed line.

Text processing and display system with means for rearranging the spatial format of a selectable section of displayed data

Abstract: This text processing and display system has the capability of effectively defining and rearranging the format of any selectable section of the block or page of alphanumeric data being displayed. The system involves the combination of a display device for simultaneously displaying a block or page comprising a plurality of lines of alphanumeric characters in ordered display position, with sequentially accessible storage means for storing coded data representations of the displayed characters in a sequence of storage positions spatially corresponding to the positions of the characters in the display block. Repetitive display scanning means are provided for traversing the character display positions in successive lines on the display device together with means for sequentially accessing the data representation for each character to be displayed from the storage means in synchronization with the display scanning means, and means for applying to the display device, signals representative of a whole character to be displayed at a display position prior to the movement of the display scanning means to the next display position whereby each whole character in the display block is refreshed before the next character is refreshed. The spatial limits for a section of stored data corresponding to the selected spatial limit of a section of alphanumeric character in the displayed block are defined by inserting coded data designating the initial character into the storage means immediately preceding the initial character data and inserting the coded data designating the final character immediately succeeding the final character data.

Data processing system with character sort apparatus

Abstract: A data processing system comprises a first storage device for storing character font data representative of a plurality of characters, each character being represented by the font data as a bit map of predetermined dimensions, the plurality of characters being stored in an ordered storage sequence. An image presentation device is capable of visually presenting an image comprised of preselected ones of the characters on a predetermined background area. A second storage device is capable of storing a bit map representation of the image, and a visual control device is capable of controlling the image presentation device to visually present the image in accordance with the character font data stored in the bit map representation of the image in the second storage device. A third storage device is capable of storing a list of identification data for at least some of the preselected characters to be visually presented, the identification data identifying the type and style of each character as well as its desired location on the background area. Finally, a data control device is capable of controlling the processing and handling of character font data and comprises a sorting device for sorting the identification data in the third storage device into the ordered storage sequence, an accessing device responsive to the sorted identification data for accessing from the first storage device in the ordered storage sequence the character font data for each character identified in the list, and a loading device for loading the character font data for each accessed character into the bit map representation in the second storage device at a location defined by the identification data for that character.

AbsoluteE0 andE2 transition rates and collective states in116Sn

Abstract: AbsoluteE0 andE2 transition rates in116Sn have been measured using several newly developed techniques. ManyE2 transitions are observed to have a collective character withB(E2) values of up to 60 W.u. The presence of deformed excited states in116Sn is discussed in view of the results obtained.

High speed character matcher and method

Abstract: A high speed character matcher and method for measuring the similarity between a pair of binary patterns representing two-dimensional images. The patterns are compared on a bit by bit basis and when a discrepancy is detected, it is assigned an error penalty which is based on the two-dimensional context in which the error occurred. The types of error context which are typical in the comparison of distorted but otherwise similar characters are given a lower error than those typically encountered in the comparison of dissimilar characters.

Digital graphics generation system

Abstract: A real time digital graphics display system is disclosed for generating circles, arcs and vectors. The system utilizes Taylor's formula to determine the successive coordinates of the points along the image of the character displayed. The system is able to display a given graphical character once given the coordinates of a start point, an end point and the number of increments to be displayed if an arc is to be displayed.

Character processing unit

Abstract: PURPOSE:To reduce the load of an operator by discriminating overall frequency information, syntax information and field information of the second character in case that the first character is converted to the corresponding second character and outputting Chinese characters from a homophonic Chinese character group sequentially from the highset-weight one. CONSTITUTION:Indication inputted from key group KB3 having key group KB1, where the first character is inputted, key group KB2 provided with a cursor shift key, etc., an automatic word Chinese character selection key, etc., is discriminated by a ROM, and contents of pointer memories PN1-PN2 are displayed on a CRT under the control of a CPU. Further, frequency information, syntax information and field information of the second character corresponding to the first character are classified and filed previously, and discrimination for homophonic Chinese character groups, syntax information, etc., is performed by the input of input keys to add weight to respective homophonic Chinese character groups and sytax information, and Chinese characters are automatically transmitted to display control circuit DCOT sequentially from the highest-weight one and are displayed on the CRT, so that the load of the operator can be reduced.

Method and apparatus for character reading

Abstract: A method for character reading requiring no character segmentation, which method effects required character recognition by the steps of subjecting a given string of character patterns to continuous scanning to produce either a local feature vector at each of the intersections of rows and columns of character patterns or a global feature vector for each of the columns formed in consequence of the scanning, linearly consolidating either or both of the feature vectors to obtain a lower dimensional vector in new feature axes and continuously matching the vectors with the standard ones set in advance.

Analytic Fourier Optics

Abstract: An extension of Fourier concepts in optics is presented, indicating the importance of analyticity for describing propagating fields. The paper highlights the particular nature of the analyticity that may be associated with fields in propagation, namely an entire and exponential type character. Such analytic functions are described uniquely by a denumerable infinity of zeros, distributed near or on the real axis. The paper presents a study of the way in which the zeros encode the information on scatterers and fields.

Reproduction of character images, particularly for typesetting apparatus

Abstract: Character images are recreated and displayed on an incrementing plotter, such as a cathode ray tube (92), with a smoothly continuous outline and not as a discontinuous assembly of stripes or dots. A master curve, e.g. a spiral, is stored electronically in a memory (16) as a sequence of vector step p instructions. The sequential outline is achieved by selecting appropriate curve sections from the memory to match the desired outline and re-orientating these curve sections so that successive sections join perfectly. The image can be displayed as designed, or one can add, subtract or modify elements of the character instantaneously. The system is especially suited for typesetting. For this, the system m provides for infilling of the outline; for smoothing the curve; for thickening vertical and/or horizontal elements of a character; for vertically compressing zones of a character; and for tracing a secondary outline just inside the main outline.