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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Natural Boundaries in Gap Detection are Related to Categorical Perception of Stop Consonants

Elangovan, Saravanan, Stuart, Andrew 30 June 2008 (has links)
Objectives: The hypothesis that a natural auditory psychophysical discontinuity contributes to a perceptual category boundary between voiced and voiceless English stop consonants was examined. Design: The relationships between voice onset time (VOT) phonetic boundary and gap-detection thresholds for conditions in which the sounds delimiting the gap were acoustically identical or different were examined in 18 native young adult English speakers. It was specifically hypothesized that between-channel gap-detection thresholds, in contrast to within-channel gap thresholds, would be better predictors of categorical VOT values for listeners. The stimuli used in the between-channel gap-detection task were designed such that dissimilar leading and trailing markers of the gap approximated a stop burst and a following vowel, both in terms of temporal and spectral relationships, while being devoid of phonetic identity. The stimuli used to examine the VOT measure were synthesized bilabial stop syllables in a continuum ranging from /ba/ to /pa/. Results: Statistically significant larger gap thresholds were found for the between-channel conditions than for the within-channel condition (p < 0.05). The center frequency of the trailing marker affected the between-channel gap thresholds with the thresholds improving as the center frequency increased (p < 0.05). Statistically significant positive correlations and predictive linear relations were found between VOT phonetic boundaries and between-channel gap thresholds (p < 0.05) but not within-channel gap thresholds (p > 0.05). Conclusions: A relationship between the phonetic boundary of voiced–voiceless speech sounds and the auditory temporal resolution task of detecting gaps placed within dissimilar markers, regardless of the center frequency of the trailing marker noise burst, was demonstrated. Detection of gaps between different nonspeech acoustic markers and categorical perception of VOT seems to share the same underlying perceptual timing mechanisms in native English speakers.
62

Electrophysiological Correlates of the Categorical Perception of Voicing

Elangovan, Saravanan, Stuart, Andrew 01 January 2006 (has links)
No description available.
63

A model of Mandarin tone categories--a study of perception and production

Yang, Bei 01 July 2010 (has links)
The current study lays the groundwork for a model of Mandarin tones based on both native speakers' and non-native speakers' perception and production. It demonstrates that there is variability in non-native speakers' tone productions and that there are differences in the perceptual boundaries in native speakers and non-native speakers. There are four experiments in this study. Experiment 1 utilizes native speakers' production data from a published speech database to explore the features of tone production by native speakers. Inter-speaker normalization is used to analyze the data. Experiment 2 synthesizes 81 tones that are carried by four sentences to measure perception by native and non-native speakers. The intra-speaker and inter-speaker normalization is used to investigate the perceptual space of T1, T2, T3, and T4. The researcher also explores the salient features distinguish native speakers' and non-native speakers' perception of the four principal tones. Experiment 3 uses both synthesized tones and natural tones that are carried by sentences to explore how pitch values of tones create overlapping areas in the perceptual map. Experiment 4 examines tone production by non-native speakers to identify the differences between native speakers' perception and non-native speakers' production; and the differences between non-native speakers' perception and their production of tones. The results of the perception and production experiments with native speakers show the perceptual boundaries and tonal categories in the perceptual space and the production space. The difference of native speakers' perception and production shows us the perceptual cue for perception. Meanwhile, the similarities of native speakers' perception and production reveal the acoustic cues, including register and contour, for tone perception and production. The results of the perception experiments with non-native speakers indicate that there are no clear boundaries, and that tone overlap in the perceptual space. Register plays an important role in the perception of tones by non-native speakers. The results of non-native speaker production also show overlapping tones in the acoustic space. The non-native speaker production appears to be determined by the contour of the tones in contrast both the contour and register determine the tonal categories of native speaker.
64

Likelihood-based inference for antedependence (Markov) models for categorical longitudinal data

Xie, Yunlong 01 July 2011 (has links)
Antedependence (AD) of order p, also known as the Markov property of order p, is a property of index-ordered random variables in which each variable, given at least p immediately preceding variables, is independent of all further preceding variables. Zimmerman and Nunez-Anton (2010) present statistical methodology for fitting and performing inference for AD models for continuous (primarily normal) longitudinal data. But analogous AD-model methodology for categorical longitudinal data has not yet been well developed. In this thesis, we derive maximum likelihood estimators of transition probabilities under antedependence of any order, and we use these estimators to develop likelihood-based methods for determining the order of antedependence of categorical longitudinal data. Specifically, we develop a penalized likelihood method for determining variable-order antedependence structure, and we derive the likelihood ratio test, score test, Wald test and an adaptation of Fisher's exact test for pth-order antedependence against the unstructured (saturated) multinomial model. Simulation studies show that the score (Pearson's Chi-square) test performs better than all the other methods for complete and monotone missing data, while the likelihood ratio test is applicable for data with arbitrary missing pattern. But since the likelihood ratio test is oversensitive under the null hypothesis, we modify it by equating the expectation of the test statistic to its degrees of freedom so that it has actual size closer to nominal size. Additionally, we modify the likelihood ratio tests for use in testing for pth-order antedependence against qth-order antedependence, where q > p, and for testing nested variable-order antedependence models. We extend the methods to deal with data having a monotone or arbitrary missing pattern. For antedependence models of constant order p, we develop methods for testing transition probability stationarity and strict stationarity and for maximum likelihood estimation of parametric generalized linear models that are transition probability stationary AD(p) models. The methods are illustrated using three data sets.
65

The development, implementation and evaluation of the Diploma of Special Education (UG 2) program at the Nepean College of Advanced Education

Fee, Richard Walter, n/a January 1976 (has links)
This field study report is concerned with the development, implementation and evaluation of a Diploma of Special Education (UG2) teacher training program. In March, 1974, the Advanced Education Beard of Mew South Wales requested that Nepean College of Advanced Education, Westmead, implement a one year training course for Generalist (Resource) Teachers in Special Education to begin in February, 1975. The lecturers in special education, Mr. Richard Fee and Mr. George Comino, proceed to design a training program which departed radically from the approach adopted by the other colleges of advanced education in New South Wales (Mitchell, Newcastle, Kuring-gai, Alexander Mackie). Instead of following the noncategorical/ commonality approach used at these colleges, Nepean chose the categorical method. With this method, the education of a number of different handicapped children is studied separately (i.e. mentally retarded, orthopaedically handicapped, etc.) rather than by studying the various disorders collectively (i.e. Exceptional Children in Society, Exceptional Children in School, etc.). In order to evaluate the effectiveness of Nepean's approach to training special education teachers, on-going and summative evaluation in a variety of forms was carried out during the first semester. This evaluation which included the administration of a pilot Teacher Competency in Special Education Self-Rating Scale clearly demonstrated that the first intake of 29 students made significant increases in their ability to teach exceptional children. The results of the evaluation also assisted the lecturers in determining areas of course weakness which could be alleviated during the second semester.
66

Utanförskap i skolan : Pedagogers tolkningar och strategier

Lundberg-Grut, Ewa January 2008 (has links)
<p>As in society in general, exclusion of individuals takes place in the school system. Even though schools – according to the curriculum – are supposed to cherish diversity, many children are left outside of the community formed during school activities. In order to gain knowledge of how schools can prevent and inhibit exclusion, this work aims to study how the problem is interpreted and managed. The study included six pedagogues: three pre-school teachers and three 1–7th grade teachers. Using a qualitative method with interviews, I have examined whether there is a difference between the two groups’ of interpretation and management of exclusion.In the analysis, the relational and categorical perspectives are used. The study shows, among other things, that the pre-school teachers are more categorical in their interpretation of exclusion than the 1–7th grade teachers. In spite of this, the pre-school teachers emphasize – to a greater extent than the 1–7th grade teachers – that the school’s social dimensions have a strong impact on their work. The study also shows that the 1–7th grade teachers have a more individualized approach to their work against exclusion. Further, the study shows that the work against exclusion of school children is mostly practised on individual- and group level, and that the particular school in this study lacks an official and joint approach for inclusion.</p>
67

Categorical structures enriched in a quantaloid: categories and semicategories

Stubbe, Isar 12 November 2003 (has links)
This thesis consists of two parts: a synthesis of the theory of categories enriched in a quantaloid; and a weakening of this theory for it to include semicategories describing ordered sheaves on a quantaloid. A synthesis of, and supplements to, results in the literature concerning the theory of categories enriched in a quantaloid Q (as particular case of categories enriched in a bicategory) is contained in the first chapters. This theory is built with Q-categories, functors and distributors, and contains such notions as, for example, adjoint functors, weighted colimits, presheaves, Kan extensions, Cauchy completions and Morita equivalence, and so on. The literature does not provide an overview of these matters, so it was necessary to provide one here. Then the necessary theory is developed to arrive at an elementary description of ``ordered sheaves on a quantaloid Q', henceforth referred to as Q-orders. As there is no ``topos of sheaves on a quantaloid', Q-orders cannot be defined as ordered objects in such a topos. Instead a description of Q-orders as categorical structures enriched in the quantaloid Q is proposed. The well-known ordered sheaves on a locale L (i.e.~ordered objects in the topos of sheaves on L) should of course be a particular example of the general theory, taking Q to be the (one-object suspension of) L. Then it turns out that the theory of Q-categories has to be weakened to include ``categories without units', i.e. Q-semicategories. But for Q-semicategories to admit a convenient distributor calculus, a ``regularity' condition has to be imposed. And for those regular Q-semicategories to admit a reasonable theory of Cauchy completions and Morita equivalence, the even stronger condition of ``total regularity' has to be imposed. The former notion has been studied before for semicategories enriched in a symmetric monoidal closed category; the latter notion is new, and is introduced via the intuitively clear idea of ``stability of objects'. The point is then that precisely the Cauchy complete totally regular Q-semicategories are the Q-orders; for a locale L they are indeed the ordered objects in the topos of sheaves on L. A (bi)equivalent description of those Q-orders can be given in terms of categories enriched in the split-idempotent completion of the quantaloid Q: a totally regular semicategory enriched in Q corresponds in a precise sense to a category enriched in the split-idempotent completion of Q. Applying this once more to a locale L instead of a quantaloid Q, these results thus deepen the work of the Louvain-la-Neuve school, and reconcile it with that of the Sydney school, on the description of (ordered) sheaves on a locale as enriched categorical structures. The extended introduction gives a compact yet intuitive presentation of the developments contained in the thesis.
68

Color Vision: Representing Material Categories

Rubin, John M., Richards, W.A. 01 May 1984 (has links)
We argue that one of the early goals of color vision is to distinguish one kind of material from another. Accordingly, we show that when a pair of image regions is such that one region has greater intensity at one wavelength than at another wavelength, and the second region has the opposite property, then the two regions are likely to have arisen from distinct materials in the scene. We call this material change circumstance the 'opposite slope sign condition.' With this criterion as a foundation, we construct a representation of spectral information that facilitates the recognition of material changes. Our theory has implications for both psychology and neurophysiology. In particular, Hering's notion of opponent colors and psychologically unique primaries, and Land's results in two-color projection can be interpreted as different aspects of the visual system's goal of categorizing materials. Also, the theory provides two basic interpretations of the function of double-opponent color cells described by neurophysiologists.
69

A Note on Object Class Representation and Categorical Perception

Riesenhuber, Maximilian, Poggio, Tomaso 17 December 1999 (has links)
We present a novel scheme ("Categorical Basis Functions", CBF) for object class representation in the brain and contrast it to the "Chorus of Prototypes" scheme recently proposed by Edelman. The power and flexibility of CBF is demonstrated in two examples. CBF is then applied to investigate the phenomenon of Categorical Perception, in particular the finding by Bulthoff et al. (1998) of categorization of faces by gender without corresponding Categorical Perception. Here, CBF makes predictions that can be tested in a psychophysical experiment. Finally, experiments are suggested to further test CBF.
70

On the Measurement of Model Fit for Sparse Categorical Data

Kraus, Katrin January 2012 (has links)
This thesis consists of four papers that deal with several aspects of the measurement of model fit for categorical data. In all papers, special attention is paid to situations with sparse data. The first paper concerns the computational burden of calculating Pearson's goodness-of-fit statistic for situations where many response patterns have observed frequencies that equal zero. A simple solution is presented that allows for the computation of the total value of Pearson's goodness-of-fit statistic when the expected frequencies of response patterns with observed frequencies of zero are unknown. In the second paper, a new fit statistic is presented that is a modification of Pearson's statistic but that is not adversely affected by response patterns with very small expected frequencies. It is shown that the new statistic is asymptotically equivalent to Pearson's goodness-of-fit statistic and hence, asymptotically chi-square distributed. In the third paper, comprehensive simulation studies are conducted that compare seven asymptotically equivalent fit statistics, including the new statistic. Situations that are considered concern both multinomial sampling and factor analysis. Tests for the goodness-of-fit are conducted by means of the asymptotic and the bootstrap approach both under the null hypothesis and when there is a certain degree of misfit in the data. Results indicate that recommendations on the use of a fit statistic can be dependent on the investigated situation and on the purpose of the model test. Power varies substantially between the fit statistics and the cause of the misfit of the model. Findings indicate further that the new statistic proposed in this thesis shows rather stable results and compared to the other fit statistics, no disadvantageous characteristics of the fit statistic are found. Finally, in the fourth paper, the potential necessity of determining the goodness-of-fit by two sided model testing is adverted. A simulation study is conducted that investigates differences between the one sided and the two sided approach of model testing. Situations are identified for which two sided model testing has advantages over the one sided approach.

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