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PubMed1998

Optimal character arrangements for ambiguous keyboards.

Many persons with disabilities lack the fine motor coordination necessary to operate traditional keyboards. For these individuals, ambiguous (or reduced) keyboards offer an alternative access method. By placing multiple characters on each key, the size and accessibility of the individual keys can be enhanced without requiring a larger keyboard. Using statistical disambiguation algorithms to automatically interpret each keystroke, these systems can approach the keystroke efficiency (keystrokes per character) of conventional keyboards. Since the placement of characters on each key determines the effectiveness of these algorithms, several methods of optimizing keyboard arrangements have previously been proposed. This paper presents a new method for optimizing an arbitrary set of N characters over a collection of M keys. While earlier efforts relied upon approximations of keystroke efficiency, the proposed approach optimizes the arrangement under this exact performance measure. Applied to the canonical 26 characters on a nine-key "telephone keypad" problem, this method provides an improvement in efficiency of 2.5 percentage points over previously established layouts. Using only a minimum of calculations, the proposed technique operates quickly and efficiently, deriving optimal arrangements in a matter of seconds using a personal computer. The flexible method is applicable to arbitrary disambiguation algorithms, character sets, and languages.

Algorithms↗
PubMed2004

Utilization of hierarchical, stochastic relationship modeling for Hangul character recognition.

In structural character recognition, a character is usually viewed as a set of strokes and the spatial relationships between them. Therefore, strokes and their relationships should be properly modeled for effective character representation. For this purpose, we propose a modeling scheme by which strokes as well as relationships are stochastically represented by utilizing the hierarchical characteristics of target characters. A character is defined by a multivariate random variable over the components and its probability distribution is learned from a training data set. To overcome difficulties of the learning due to the high order of the probability distribution (a problem of curse of dimensionality), the probability distribution is factorized and approximated by a set of lower-order probability distributions by applying the idea of relationship decomposition recursively to components and subcomponents. Based on the proposed method, a handwritten Hangul (Korean) character recognition system is developed. Recognition experiments conducted on a public database show the effectiveness of the proposed relationship modeling. The recognition accuracy increased by 5.5 percent in comparison to the most successful system ever reported.

Algorithms↗
PubMed2003

Reproductive character displacement and the genetics of gamete recognition in tropical sea urchins.

Reproductive character displacement occurs when sympatric and allopatric populations of a species differ in traits crucial to reproduction, and it is commonly thought of as a signal of selection acting to limit hybridization. Most documented cases of reproductive character displacement involve characters that are poorly understood at the genetic level, and rejecting alternative hypotheses for biogeographic shifts in reproductive traits is often very difficult. In sea urchins, the gamete recognition protein bindin evolves under positive selection when species are broadly sympatric, suggesting character displacement may be operating in this system. We sampled sympatric and allopatric populations of two species in the sea urchin genus Echinometra for variation in bindin and for the mitochondrial cytochrome oxidase I to examine patterns of population differentiation and molecular evolution at a reproductive gene. We found a major shift in bindin alleles between central Pacific (allopatric) and western Pacific (sympatric) populations of E. oblonga. Allopatric populations of E. oblonga are polyphyletic with E. sp. C at bindin, whereas sympatric populations of the two species are reciprocally monophyletic. There is a strong signal of positive selection (P(N)/P(S) = 4.5) in the variable region of the first exon of bindin, which is associated with alleles found in sympatric populations of E. oblonga. These results indicate that there is a strong pattern of reproductive character displacement between E. oblonga and E. sp. C and that the divergence is driven by selection. There is much higher population structure in sympatric populations at the bindin locus than at the neutral mitochondrial locus, but this difference is not seen in allopatric populations. These data suggest a pattern of speciation driven by selection for local gamete coevolution as a result of interactions between sympatric species. Although this pattern is highly suggestive of speciation by reinforcement, further research into hybrid fitness and egg-sperm interactions is required to address this potential mechanism for character displacement.

Amino Acid Sequence↗
PubMed2004

Interspecific aggression and character displacement in the damselfly Calopteryx splendens.

Problems in species recognition are thought to affect the evolution of secondary sexual characters mainly through avoidance of maladaptive hybridization. Another, but much less studied avenue for the evolution of sexual characters due to species recognition problems is through interspecific aggression. In the damselfly, Calopteryx splendens, males have pigmented wing spots as a sexual character. Large-spotted males resemble males of another species, Calopteryx virgo, causing potential problems in species recognition. In this study, we investigate whether there is character displacement in wing spot size and whether interspecific aggression could cause this pattern. We found first that wing spot size of C. splendens in populations decreased with increasing relative abundance of C. virgo. Secondly, C. virgo males were more aggressive towards large- than small-spotted C. splendens males. Thirdly, in interspecific contests C. virgo males had better territory holding ability than C. splendens males. These results suggest that interspecific aggression may have caused character displacement in wing spot size of C. splendens, because the intensity of aggression towards large-spotted males is likely to increase with relative abundance of C. virgo males. Thus, interspecific aggression may be an evolutionarily significant force that is able to cause divergence in secondary sexual characters.

Aggression↗
PubMedDate not supplied

Death rates of characters in soap operas on British television: is a government health warning required?

OBJECTIVE: To measure mortality among characters in British soap operas on television. DESIGN: Cohort analysis of deaths in EastEnders and Coronation Street, supplemented by an analysis of deaths in Brookside and Emmerdale. MAIN OUTCOME MEASURES: Standardised mortality ratios and the proportional mortality ratio for deaths attributable to external causes (E code of ICD-9 (international classification of diseases, ninth revision). RESULTS: Staying alive in a television soap opera is not easy. Standardised mortality ratios for characters were among the highest for any occupation yet described (771 (95% confidence interval 415 to 1127) for characters in EastEnders), and this was not just because all causes of death were overrepresented. Deaths in soap operas were almost three times more likely to be from violent causes than would be expected from a character's age and sex. A character in EastEnders was twice as likely as a similar character in Coronation Street to die during an episode. CONCLUSIONS: The most dangerous job in the United Kingdom is not, as expected, bomb disposal expert, steeplejack, or Formula One racing driver but having a role in one of the United Kingdom's most well known soap operas. This is the first quantitative estimate of the size of the pinch of salt which should be taken when watching soap operas.

Adolescent↗
PubMed1995

Recognition of Telugu characters using neural networks.

The aim of the present work is to recognize printed and handwritten Telugu characters using artificial neural networks (ANNs). Earlier work on recognition of Telugu characters has been done using conventional pattern recognition techniques. We make an initial attempt here of using neural networks for recognition with the aim of improving upon earlier methods which do not perform effectively in the presence of noise and distortion in the characters. The Hopfield model of neural network working as an associative memory is chosen for recognition purposes initially. Due to limitation in the capacity of the Hopfield neural network, we propose a new scheme named here as the Multiple Neural Network Associative Memory (MNNAM). The limitation in storage capacity has been overcome by combining multiple neural networks which work in parallel. It is also demonstrated that the Hopfield network is suitable for recognizing noisy printed characters as well as handwritten characters written by different "hands" in a variety of styles. Detailed experiments have been carried out using several learning strategies and results are reported. It is shown here that satisfactory recognition is possible using the proposed strategy. A detailed preprocessing scheme of the Telugu characters from digitized documents is also described.

Algorithms↗
PubMed1982

Phylogeny through brain traits: fifteen characters which adumbrate mammalian genealogy.

Fifteen characters of brain organization are identified for which primitive and derived states can be distinguished, and which are thus useful in reconstructing mammalian phylogeny. The states of the characters are numerically coded in sequence from most primitive to most derived, to facilitate reciprocal comparisons in comprehensive genealogical analyses. The characters include certain features of cerebral circulation, cytoarchitecture, fiber pathways, and sensory projections. Seven characters are shared with nonmammals, a fact which makes then particularly useful for establishing their primitive vs. derived states; the other eight characters are features peculiar to mammals. Ten characters provide impressive reinforcement for traditional major grouping of the species, while five provide bases for new ideas about mammalian relationships.

Animals↗
PubMed2003

GapCoder automates the use of indel characters in phylogenetic analysis.

BACKGROUND: Several ways of incorporating indels into phylogenetic analysis have been suggested. Simple indel coding has two strengths: (1) biological realism and (2) efficiency of analysis. In the method, each indel with different start and/or end positions is considered to be a separate character. The presence/absence of these indel characters is then added to the data set. ALGORITHM: We have written a program, GapCoder to automate this procedure. The program can input PIR format aligned datasets, find the indels and add the indel-based characters. The output is a NEXUS format file, which includes a table showing what region each indel characters is based on. If regions are excluded from analysis, this table makes it easy to identify the corresponding indel characters for exclusion. DISCUSSION: Manual implementation of the simple indel coding method can be very time-consuming, especially in data sets where indels are numerous and/or overlapping. GapCoder automates this method and is therefore particularly useful during procedures where phylogenetic analyses need to be repeated many times, such as when different alignments are being explored or when various taxon or character sets are being explored. GapCoder is currently available for Windows from http://www.home.duq.edu/~youngnd/GapCoder.

Algorithms↗
PubMed2006

SIMMAP: stochastic character mapping of discrete traits on phylogenies.

BACKGROUND: Character mapping on phylogenies has played an important, if not critical role, in our understanding of molecular, morphological, and behavioral evolution. Until very recently we have relied on parsimony to infer character changes. Parsimony has a number of serious limitations that are drawbacks to our understanding. Recent statistical methods have been developed that free us from these limitations enabling us to overcome the problems of parsimony by accommodating uncertainty in evolutionary time, ancestral states, and the phylogeny. RESULTS: SIMMAP has been developed to implement stochastic character mapping that is useful to both molecular evolutionists, systematists, and bioinformaticians. Researchers can address questions about positive selection, patterns of amino acid substitution, character association, and patterns of morphological evolution. CONCLUSION: Stochastic character mapping, as implemented in the SIMMAP software, enables users to address questions that require mapping characters onto phylogenies using a probabilistic approach that does not rely on parsimony. Analyses can be performed using a fully Bayesian approach that is not reliant on considering a single topology, set of substitution model parameters, or reconstruction of ancestral states. Uncertainty in these quantities is accommodated by using MCMC samples from their respective posterior distributions.

Animals↗
PubMed2005

Homosexuality in TV situation comedies: characters and verbal comments.

A content analysis was conducted on 22 television situation comedies in order to determine the incidence of homosexual characters, their demographics (sex, age and race/ethnicity), and whether they verbally comment about sexual orientation. One episode of each program appearing in early October 2000 was video recorded and analyzed for its contents by trained coders. Only 2% of the 125 central characters were homosexual; thus, homosexuality is significantly under-represented in programs that adolescents and young adults watch compared to actual prevalence rates of homosexuality in North America (10-13%). All the homosexual characters were male and in the 20-35-year-old age group; this indicates that homosexual adolescent viewers have no peer role models with whom to identify. Homosexual characters made significantly more comments about sexual orientation than heterosexual characters. This suggests that television writers/producers present sexual orientation as a significant theme in the lives of homosexual characters.

Adolescent↗
PubMed1999

Equivalent blur as a function of spurious response of a sampled imaging system: application to character recognition.

Image sampling effects have been variously quantified as aliased signal, spatial signal, and spatial noise. However, a relationship between these characteristics and human object recognition has not been established in a coherent, mathematical form. We present a heuristic study that characterizes the performance degradation that is due to the spurious response of a sampled imaging system as an effective increase in system blur. A character recognition experiment was performed in which 20 observers responded to 3500 character pairs of blur and sample spacing. A baseline was created where the probability of character recognition was determined as a function of blur without sampling. The sampled characters were then compared with this baseline so that the effect of sampling on character recognition could be determined. Finally, an increase in blur was established as a function of spurious response, which describes the overall effect of sampling on observer character recognition.

Darkness↗
PubMed2001

Phylogeny of Steinernema travassos, 1927 (Cephalobina: Steinernematidae) inferred from ribosomal DNA sequences and morphological characters.

Entomopathogenic nematodes in Steinernema, together with their symbiont bacteria Xenorhabdus, are obligate and lethal parasites of insects that can provide effective biological control of some important lepidopteran, dipteran, and coleopteran pests of commercial crops. Phylogenetic relationships among 21 Steinernema species were estimated using 28S ribosomal DNA (rDNA) sequences and morphological characters. Sequences of the rDNA internal transcribed spacers were obtained to provide additional molecular characters to resolve relationships among Steinernema carpocapsae, Steinernema scapterisci, Steinernema siamkavai, and Steinernema monticolum. Four equally parsimonious trees resulted from combined analysis of 28S sequences and 22 morphological characters. Clades inferred from analyses of molecular sequences and combined datasets were primarily reliably supported as assessed by bootstrap resampling, whereas those inferred from morphological data alone were not. Although partially consistent with some traditional expectations and previous phylogenetic studies, the hypotheses inferred from molecular evidence, and those from combined analysis of morphological and molecular data, provide a new and comprehensive framework for evaluating character evolution of steinernematids. Interpretation of morphological character evolution on 6 trees inferred from sequence data and combined evidence suggests that many structural features of these nematodes are highly homoplastic, and that some structures previously used to hypothesize relationships represent ancestral character states.

Animals↗
PubMed2006

Ecological opportunity and phenotypic plasticity interact to promote character displacement and species coexistence.

We investigated the roles of resource availability and phenotypic plasticity in promoting ecological character displacement (i.e., trait evolution stemming from resource competition between species). Because ecological character displacement generates new populations that differ in resource use, this process should only occur when exploitable resources are available. We tested this hypothesis in two species of spadefoot toads (Spea bombifrons and S. multiplicata) whose tadpoles use phenotypic plasticity to develop into either an omnivore morph, which specializes on detritus, or a physically distinctive carnivore morph, which specializes on shrimp. Both species grow best on shrimp, but when reared together, S. bombifrons outcompetes S. multiplicata for shrimp and S. multiplicata outcompetes S. bombifrons for detritus. We found that when each species occurred alone in the field, they produced similar proportions of omnivores and carnivores. When the two species occurred together, however, they underwent ecological character displacement in larval development, with S. multiplicata producing mostly omnivores, and S. bombifrons producing mostly carnivores. We combined observations of natural populations with experiments to evaluate whether such character displacement was only possible when both shrimp and detritus were relatively abundant. Mixed-species ponds contained abundant detritus and shrimp, in contrast with nearby pure-species ponds, which were deficient in one resource. Experiments revealed that S. multiplicata competed poorly when detritus was rare and that S. bombifrons competed poorly when shrimp was rare. In nature, when one of these two resources was scarce, one species was missing, perhaps through competitive exclusion by the species that was the superior competitor for the remaining resource. Thus, ecological character displacement and, therefore, coexistence of close competitors, was only possible when diverse resources were available. Finally, even if exploitable resources are available, character displacement is not guaranteed to transpire if species cannot utilize such resources expeditiously. Phenotypic plasticity provides a general and important mechanism for facilitating resource partitioning. Thus, by facilitating shifts in resource use, phenotypic plasticity and ecological opportunity may often interact to promote divergence and coexistence of competitors.

Adaptation, Physiological↗
PubMed2003

Target locations in visual field and character recognition by students of Chinese.

The potential influence of target location in a visual field on search should be considered in layouts of control panels and advertisements. This investigation was done to verify the assumption that the upper-left portion of a page or its equivalent naturally attracts the attention of the viewer. Exp. 1 used a tachistoscope to test which of eight Chinese characters first attracted the attention of viewers. The eight Chinese characters are arranged in a square and a circular configuration. In the square layout, a large square (18 cm x 18 cm) was first conceptually subdivided into nine equal parts (6 cm x 6 cm). Then, the eight Chinese characters were put in the center of each part, leaving the central part blank. In the circular layout, the same Chinese characters were symmetrically placed on the conceptual circumference (r = 6 cm) of a circle within a large square. Exp. 2 was a paper-and-pencil test. An embedded-fault-character-search was used to examine the location of the first faulty character discovered by the subjects. 60 college students and 36 schoolchildren were selected as subjects for the tachistoscopic experiment and paper-and-pencil test. Finally, five graduate students participated in Exp. 3 in which an eye camera registered subjects' eye movements to measured distribution of durations of looking over eight locations. The measurements indicated a slight predominance of the upper-left portion for college students and graduate students, and a slight predominance of the upper-right portion for schoolchildren.

Adult↗
PubMed2000

A Japanese logographic character frequency list for cognitive science research.

This paper describes a Japanese logographic character (kanji) frequency list, which is based on an analysis of the largest recently available corpus of Japanese words and characters. This corpus comprised a full year of morning and evening editions of a major newspaper, containing more than 23 million kanji characters and more than 4,000 different kanji characters. This paper lists the 3,000 most frequent kanji characters, as well as an analysis of kanji usage and correlations between the present list and previous Japanese frequency lists. The authors believe that the present list will help researchers more accurately and efficiently control the selection of kanji characters in cognitive science research and interpret related psycholinguistic data.

Cognitive Science↗
PubMed2001

Generalized frequency coding: a method of preparing polymorphic multistate characters for phylogenetic analysis.

A new method of coding polymorphic multiistate characters for phylogenetic analysis is presented. By dividing such characters into subcharacters, their frequency distributions can be represented with discrete states. Differential weighting is used to counter the effect of representing one character with multiple characters. The new method, generalized frequency coding (GFC), is potentially superior to previously used methods in that it incorporates more information and is applicable to both qualitative and quantitative characters. When applied to a previously published data set that includes both types of polymorphic multistate characters, the method performed well, as assessed with g1 and nonparametric bootstrap statistics and giving results congruent with those of other studies. The data set was also used to compare GFC with both gap-weighting and Manhattan distance step matrix coding. On these grounds and for philosophical reasons, we consider GFC to be a better estimator of phylogeny.

Animals↗
PubMed2002

Role of structure and component in judgments of visual similarity of Chinese characters.

Skilled readers of Chinese participated in sorting and visual search experiments. The sorting results showed that under conditions of conflicting information about structure and component, subjective judgments of the visual similarity among characters were based on the characters' overall configurations (i.e., structures) rather than on the common components the characters possessed. In visual search, both structure and component contributed to the visual similarity reflected by the search efficiency. The steepest search slopes (thus the most similar target-distractor pairs) were found when the target and the distractor characters had the same structure and shared 1 common component, compared with when they had different structures and/or shared no common components. Results demonstrated that character structure plays a greater role in the visual similarity of Chinese characters than has been considered.

Form Perception↗
PubMed2003

[Cyclothymia and typus melancholicus: empirical study on personality character of mood disorder].

PURPOSE: 1. To investigate whether depressive, cyclothymic, hyperthymic and irritable temperaments as identified by TEMPS-A are characteristic to monopolar or bipolar disorder. 2. To investigate the independency and to discuss the clinical validity of the temperaments. 3. To replicate the previous studies whether Typus Melancholicus is characteristic to monopolar disorder. 4. To investigate the relationship between Typus Melancholicus and mood dysregulation, and the relationship, if any, is characteristically observed with monopolar disorder. 5. To discuss the difference between monopolar and bipolar disorder in terms of personality character. SAMPLE: Monopolar and bipolar groups were recruited consecutively from the patients who received outpatient treatment at Kanto Medical Center between September and November, 2001. The age is between 18 and 60. The exclusion criteria were psychotic disorder, organic disorder, grave physical illness and non-remitted mood symptoms (HRSD > 11 and MRS > 13). Control group was selected from 1391 company employees who participated in TEMPS-A research project between May 2001 and May 2002, matching gender and age with monopolar and bipolar groups. The exclusion criterion was marked depressive symptom (CES-D > 16). STATISTICAL ANALYSIS: The statistical analyses were done with Kruskal-Wallis test and Mann-Whitney U test with Bonferroni's correction regarding the difference among the groups. Spearman coefficients were examined regarding the independency of temperaments. The relationship between Typus Melancholicus and mood dysregulation was examined by mono-regression analysis. RESULT AND DISCUSSION: Depressive and cyclothymic temperaments scores did not differ significantly between monopolar and bipolar. These scores were significantly higher in monopolar and bipolar than in control. Therefore, these temperaments are evidenced to be characteristic with mood disorder. But between monopolar and bipolar there was no significant difference. Irritable temperament score did not differ significantly among the three groups. This score showed a highly significant correlation with cyclothymic and depressive temperaments. Irritable temperament seems closely related with the personality character of mood disorder, however this temperament itself was not characteristic. Hyperthymic temperament score was mildly significantly lower in bipolar than in control. There was no other significant inter-group difference. This temperament hardly showed a correlation with other temperaments. Though hyperthymic temperament may be hypothesized characteristic with manic patients, the result did not support this hypothesis. Typus Melancholicus score did not differ significantly among three groups. This result contradicts with a number of previous studies. It seems that the prevalence of Typus Melancholicus among the groups should be further investigated. Typus Melancholicus showed a mild correlation with depressive temperament in monopolar and with depressive, cyclothymic and irritable and temperaments in bipolar. Regarding mono-regression analysis, no temperament predicted Typus Melancholicus formation in monopolar. Depressive, cyclothymic and irritable temperaments predicted significantly in bipolar. In control group, hyperthymic temperament predicted midly significantly, but the prediction rate was as small as 7%. These results seem to support the theories of Shimoda and Matussek that Typus Melancholicus characters are related with bipolar disorder. Between monopolar and bipolar, there was not much significant difference in terms of personality characteristics. This seems to suggest no marked personality character difference between these groups and supports Akiskal's concept of Bipolar Spectrum. CONCLUSION: 1. Depressive and Cyclothymic temperaments are characteristic with mood disorder. 2. Hyperthymic temperament is independent, but not characteristic with mood disorder. 3. Irritable temperament may be modifying the personality character of mood disorder. 4. Typus Melancholicus was not characteristic to monopolar disorder. 5. Significant relationship between Typus Melancholicus and mood dysregulation was observed in bipolar group. 6. There seems no substantial difference between monopolar and bipolar disorders in terms of personality character.

Adolescent↗