Showing papers on "Character (mathematics) published in 1986"

Phenotypic plasticity: an evolving plant character

Abstract: Phenotypic plasticity is an important mode of adaptation to temporal and spatial environmental variability, particularly in plants. Although data are available concerning interspecific differences in the sizes and shapes of characters, there is little information concerning differences between taxa for the plastic responses of those characters. We have measured: (1) the mean value of a character, (2) the amount of character plasticity, and (3) the pattern of phenotypic plasticity for species in five genera, and calculated the divergences among species for each of these three measures. We compared the divergences of these measures to address the question of whether there is a relationship between the evolution of the character means of species and the evolution of the plasticities of those characters. We found that the evolutionary divergence of character plasticities could be independent of the interspecific divergence of character means. There was, however, a tendency for the divergence of amounts and patterns of plasticity to be related.

Bora-aromatic systems. Part 8. The physical and chemical consequences of cyclic conjugation in boracyclopolyenes. The antiaromatic character of pentaarylboroles.

Abstract: Pentasubstituted boroles or boracyclopentadienes have been prepared by two routes: (1) the interaction of an (E&)-( 1,2,3,4-tetraaryl-1,3-butadien-l,4-ylidene)dilithium in ether solution with an aryl(diha1o)borane to form the borole etherate; and (2) the exchange reaction between a 1,1-dialky1-2,3,4,5-tetraarylstannole in nondonor media to produce the unsolvated borole. The boroles are unexpectedly strong Lewis acids, complexing with amines and even ethers and nitriles, and very prone to oxidation, solvolytic cleavage, and Diels-Alder reactions. The foregoing chemical behavior, taken together with their unusual nuclear magnetic and electronic spectral properties, can be straightforwardly interpreted in terms of the Hiickel antiaromatic character of the 4-*-electron boracyclopentadiene nucleus. By treating such nuclei as perturbed cyclopentadienyl 7r-systems, a qualitative understanding of both the spectral and chemical properties can be attained. From such considerations, it is evident that the conjugation between the tricoordinate boron's 2p,-orbital and the four-carbon butadienylidene array is destabilizing and is the source of the high reactivity of boroles. An $-hybridized boron atom might be expected to form cyclic conjugated systems with arrays of sp2-hybridized carbons, because both the covalent radius (0.80 A) and the Allred-Rochow electronegativity (2.01) of boron are similar to those of carbon (0.77 A and 2.51).4 In such conjugated rings the boron center might exert a stabilizing influence if the total number of x electrons would conform to the Hiickel 4n + 2 criterion for a r o m a t i ~ i t y . ~ ~ In fact, heterocyclic organoboranes bearing the isoelectronic J3=N unit in place of one or more C=C linkages of a benzenoid ring have been shown to possess chemical and physical properties similar to classic aromatic compounds.5b Boracyclopolyenes not possessing the appropriate number of ?r electrons might be destabilized by conjugation and accordingly display unusual reactivity or antiaromaticityS6 An example of the destabilization of a carbocyclic ring by such antiaromaticity is the instability of the pentaphenylcyclopentadienyl cation (1). This deep-blue ion is highly reactive and has a thermally populated triplet (compound 2). This behavior indicates that the gain in conjugated stabilization attained by placing the four A electrons as pairs in bonding molecular orbitals is not large.

Different by Design: The Context and Character of Three Magnet Schools

Abstract: By exploring the lives of three magnet schools in a large American city, the author shows how these schools were affected by community political struggles. The book reveals the influences which shape students' experiences in the USA.

Character and pattern recognition machine and method

Abstract: A pattern recognition system, particularly a handprint character recognition system in which electrical binary black/white "image" of one or more handprinted characters is formed and a plurality of centers of recognition (CORs) within said binary black/white images are selected as reference points for measuring the characteristic enclave of the black/white image immediately surrounding the CORs. A library of templates of said measurements around the CORs for a plurality of known exemplary character images is stored in a memory for comparison with corresponding measurements made around the CORs of images whose class is unknown to produce "template scores" proportional to the similarity of the enclaves of the known image to the enclaves measured by templates. The generic shape of a character is expressed as a "character equation" involving template scores developed on an unknown image, and each character equation is evaluated including comparing the values of such equations, and selecting the best value to determine the generic name of the unknown character.

A Rational Basis for a Priori Character Weighting

Abstract: Previously presented arguments for and against character weighting in systematic analyses are briefly reviewed and the bases for different weighting methods summarized. A priori and a posteriori methods are defined. I conclude that a priori weighting is the only noncircular approach for weighting of characters in the construction or recognition of groups of taxa, but that no objective method of a priori weighting has been proposed to date. A hy- pothetico-deductive methodology for character analysis completely prior to and independent of cladistic analysis (or phylogeny reconstruction) is briefly summarized. Identifications and characters are shown to be hypotheses testable prior to the construction of a cladogram. In that context, rather than attempting to weight on intrinsic properties of characters as suggested up to now, weighting on the basis of the relative degree of corroboration of the character in the character analysis provides a rational basis for character weighting if character conflicts occur in the cladistic analysis. (Character analysis; cladistic analysis; character weighting; phylogenetic analysis.) Two questions have traditionally been addressed in the evaluation of character weighting methods in systematic analysis. One is: can we judge the importance or reliability of a character's contribution to our estimates of relationships among taxa and, if so, how can we do so? The second question is: even if we can judge a char-

Method and apparatus for pattern recognition

Abstract: A method and apparatus for recognizing an unknown character, pattern, or indicia, or the like as being a particular one of a group of known reference characters, patterns, indicia, or the like. In the preferred embodiment, the system converts scanned and digitized MICR data and uses it to identify the character. The reference characters and the unknown character are Fourier Transformed and various corrections are made for eliminating the absolute amplitude difference from the recognition process, while simultaneously providing a method of correcting for position differences between the reference charcter and the unknown character. Provisions are made for weighting the phase differences proportional to the expected accuracy of the phase data to minimize the effects of noise on the measurement, and for combining the amplitude and phase data to define a single "best match" criteria for the unknown character. The input data is stored in memory and later converted to real and imaginary frequency components through the Fourier Transform process. The real and imaginary parts are converted to amplitude and phase as a function of frequency and both the amplitude and the phase data are corrected for position errors and the like. They are then compared to a set of amplitude and phase data for the group of standard known characters. The particular one of the known reference characters which is closest to the transform of the unknown character is designated as the "best match". The second minimum is located, and the percentage that the best match is better than the second best match is used to determine a margin of error criteria.

Method and apparatus for constructing, storing and displaying characters

Abstract: A method and apparatus for creating and storing characters for display on a video screen. The shape of the graphic character is displayed at various degrees of resolution. The graphic character is stored as a bitmap or as coefficients of spline curves. These can be scaled up or down to give different character sizes. The coefficients can be converted to form pixelmaps which are rectangular arrays of pixels. The pixelmaps may have gray scale values.

Loss of evolution in the flow of viscoelastic fluids

Abstract: For the Maxwell model, it has been proved that an initially evolutionary flow remains so at any time: the property is transported along the streamlines. This is generally not the case for other differential models. A complete study is made of the local properties which are conserved by a Johnson-Segalman fluid flow. Evolution is not preserved, and counter examples are given where the evolutionary character is indeed lost. Two conservation properties are demonstrated and their relationship with the Second Law is also examined. The evolutionary character of a system is a physical requirement which should be satisfied by all models.

Recognition system for run-on handwritten characters

Abstract: A method of processing a word with the segmentation and recognition steps combined into an overall scheme. This is accomplished by a three step procedure. First, potential or trail segmentation points are derived. This is done in a manner so as to ensure that essentially all true segmentation points are present but also includes extra or not true segmentation points. Second, all combinations of the segments that could reasonably be a character are sent to a character recognizer to obtain ranked choices and corresponding scores. Finally, the recognition results are sorted and combined so that the character sequences having the best cummulative scores are obtained as the best word choices. For a particular word choice there is a corresponding character segmentation, simply the segment combinations that resulted in the chosen characters. With this recognition scheme the initial character segmentation is not final and need not be highly accurate, but is subject to a lesser constraint of containing the true segmentation points.

A further study on the discretisation of the Griffin-Hill-Wheeler equation

Abstract: It is shown that the discretisation of the Griffin-Hill-Wheeler equation is independent of the character of the weight functionf(α). The possibility of obtaining accurate weight functions through discretisation is discussed and the methods proposed are compared with an existing variational technique. The applications include the classical variational problem of representing hydrogen orbitals in terms of Gaussians as an optimal case.

Method and apparatus for data hashing using selection from a table of random numbers in combination with folding and bit manipulation of the selected random numbers

Abstract: A data hashing arrangement particularly suitable for efficient database storage and fast retrieval of large numbers of character strings. A database address is determined for a character string by replacing individual characters with random numbers selected from a predefined table of random numbers. The table locations of the selected random numbers are uniquely defined by the characters. The selected numbers are combined by iteractive bit reordering and exclusive-OR operations to form a result, which is then used to derive the database address where the character string is stored.

Dimensional Relationships of Aided Recall and Recognition

Abstract: The advertising literature contains some evidence that memory measures, such as aided recall and recognition, are multidimensional in nature, but little is known about the character of the separate dimensions. This issue is investigated in the present study by including correlates of aided recall and recognition. The results of an ESSCA analysis indicate that there are at least two independent dimensions of memory for advertisements. The first dimension is related to positive affective reactions to the ad, brand and product category, and the second is related to knowledge or ability differences between individuals.

Character recognition system

Abstract: A character recognition system extracts character blocks to contain a minimum character unit therein. The character recognition system has the capability of re-combining and/or re-extracting character blocks during the character recognition process. Re-combination and re-extraction of the character blocks is controlled based on the history of the extraction process for each of the character blocks so that re-combination and re-extraction can be performed effectively.

Character weighting and cladistic analysis

Abstract: Explicit, ad hoc character weighting, widely dismissed by cladists as too subjective for practical application, can be useful in resolving difficult instances of homoplasy. Such weighting should be avoided to the extent possible, and should only be tried when critical reexamination of the evidence and the parsimony criterion have failed. So long as such uses of weighting are fully explicit and their results are viewed as tentative solutions, they support formulations of hypotheses where none might otherwise be possible. (Character weighting; cladistics; phylogenetics; convergence; homoplasy.)

Phylogenetic relationships of captorhinomorph reptiles

Abstract: The Captorhinomorpha consists of two families, the Captorhinidae and the Protorothyrididae. The distribution of morphological character states of the skeleton permits reevaluation of currently acce...

Image processing apparatus for combining image and character data

Abstract: An image processing apparatus, for combining image and character data, has a character code buffer for receiving a decoded character signal and generating data presenting a designated character image portion in response a character read address signal, a character generator for converting the readout data to dot data, a character image memory for storing the dot data in a memory area in response to a character write address signal, an image buffer memory for receiving decoded image data and generating data representing a designated half tone image region in response to a half tone read address signal, processing circuit blocks for performing a series of predetermined operations for the readout data, and a half tone image memory for storing the processed data in response to a half tone write address signal.

The Complementary Goals of Character Development and Academic Excellence.

Abstract: T o serve their rightful role in society, schools need to focus jointly on the educational goals of character development and aca demic learning These two goals are not mutually exclusive, but are entire ly complementary (Wynne and Wal berg 198S) By our definition, "character' in volves engaging in morally relevant conduct or words or refraining from certain conduct or words Put another way, character, good or bad is observ able Of course, character is signifi cantly affected by feelings and values, but the final test of good or moral feelings is whether individuals act in an appropriate fashion

Data entry method and apparatus for the disabled

Abstract: A method and apparatus allows a user to scan through a predetermined character set through the implementation of a continuously variable volitional signal, and for selecting a specific character. The scanning rate is proportional to the user controlled volitional signal.

Questions, answers, and responses: interacting with knowledge base systems

Abstract: The purpose of this chapter is to examine the character of information-seeking interactions between a user and a knowledge base system (KBS). In doing so, I advocate that a clear distinction be made between an answer to a question and a response. The chapter characterizes questions, answers, and responses, the role they play in effective information interchanges, and what is involved in facilitating such interactions between user and KBS.

The Virtues of Aristotle

Abstract: Preface 1. Introduction 2. What A Hexis Is 3. Man: His Ergon and His Excellence 4. A Virtue is a Trait of Character 5. The Virtues Are Concerned With Choice 6. A Virtue is a Hexis of Character. Notes. Bibliography. Index of Aristotelian Passages

Continuous characters recognition system

Abstract: A recognition system for recognizing a plurality of continuous hand-written characters, employing a first memory in which isolated characters are stored, and a second memory which stores information, including interstroke character information, for connecting isolated characters. According to various embodiments of the invention, this interstroke information may be stored as part of a continuous character, or by itself.