• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 434
  • 177
  • 47
  • 45
  • 33
  • 18
  • 14
  • 11
  • 11
  • 10
  • 9
  • 8
  • 6
  • 5
  • 4
  • Tagged with
  • 973
  • 133
  • 131
  • 128
  • 127
  • 87
  • 83
  • 79
  • 79
  • 75
  • 73
  • 73
  • 71
  • 65
  • 64
  • 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.
501

A teacher's handbook Post-traumatic Vision Syndrome: Awareness, assessments, accommodations

Lewis, Elaine Ruth 01 January 2006 (has links)
The purpose of the project is to construct a handbook for pre-school, elementary and middle school teachers that will provide the information essential in developing an awareness of the signs and symptoms of a traumatic brain related to a ocular motor injury. Also included in the handbook are recommended assessments and accommodations that can be utilized in the management of PTVS.
502

Universal graph literacy: understanding how blind and low vision students can satisfy the common core standards with accessible auditory graphs

Davison, Benjamin Kenneth 08 April 2013 (has links)
Auditory graphs and active point estimation provide an inexpensive, accessible alternative for low vision and blind K-12 students using number lines and coordinate graphs. In the first phase of this research program, a series of four psychophysics studies demonstrated an interactive auditory number line that enables blind, low vision, and sighted people to find small targets with a laptop, headphones, and a mouse or a keyboard. The Fitts' Law studies showed that, given appropriate auditory feedback, blind people can use a mouse. In addition, auditory feedback can generate target response patterns similar to when people use visual feedback. Phase two introduced SQUARE, a novel method for building accessible alternatives to existing education technologies. The standards-driven and teacher-directed approach generated 17 graphing standards for sixth grade mathematics, all of which emphasized point estimation. It also showed that how only few basic behavioral components are necessary for these graphing problems. The third phase evaluated active point estimation tools in terms of training, classroom situations, and a testing situation. This work shows that students can learn to graph in K-12 environments, regardless of their visual impairment. It also provides several technologies used for graphing, and methods to further develop education accessibility research.
503

New Ways of Seeing: Examining Musuem Accessibility for Visitors with Vision Impairments

Sbarra, Wendy M 12 August 2012 (has links)
While I have always loved to go to the art museum I have often found it difficult to convince friends and family to go with me. It seems to be a particularly daunting task for visitors with disabilities and specifically those with vision impairments. This study surveys the accessibility of the programming for visitors with visual impairments at 25 art museums in the United States of America and how they communicate that information to potential visitors. It highlights museums that go beyond what is required by the Americans with Disabilities Act and create programming that is enjoyable for all. This study will be a reference to create a more enjoyable experience for all.
504

Blind Detection Techniques For Spread Spectrum Audio Watermarking

Krishna Kumar, S 10 1900 (has links)
In spreads pectrum (SS)watermarking of audio signals, since the watermark acts as an additive noise to the host audio signal, the most important challenge is to maintain perceptual transparency. Human perception is a very sensitive apparatus, yet can be exploited to hide some information, reliably. SS watermark embedding has been proposed, in which psycho-acoustically shaped pseudo-random sequences are embedded directly into the time domain audio signal. However, these watermarking schemes use informed detection, in which the original signal is assumed available to the watermark detector. Blind detection of psycho-acoustically shaped SS watermarking is not well addressed in the literature. The problem is still interesting, because, blind detection is more practical for audio signals and, psycho-acoustically shaped watermarks embedding offers the maximum possible watermark energy under requirements of perceptual transparency. In this thesis we study the blind detection of psycho-acoustically shaped SS watermarks in time domain audio signals. We focus on a class of watermark sequences known as random phase watermarks, where the watermark magnitude spectrum is defined by the perceptual criteria and the randomness of the sequence lies in their phase spectrum. Blind watermark detectors, which do not have access to the original host signal, may seem handicapped, because an approximate watermark has to be re-derived from the watermarked signal. Since the comparison of blind detection with fully informed detection is unfair, a hypothetical detection scheme, denoted as semi-blind detection, is used as a reference benchmark. In semi-blind detection, the host signal as such is not available for detection, but it is assumed that sufficient information is available for deriving the exact watermark, which could be embedded in the given signal. Some reduction in performance is anticipated in blind detection over the semi-blind detection. Our experiments revealed that the statistical performance of the blind detector is better than that of the semi-blind detector. We analyze the watermark-to-host correlation (WHC) of random phase watermarks, and the results indicate that WHC is higher when a legitimate watermark is present in the audio signal, which leads to better detection performance. Based on these findings, we attempt to harness this increased correlation in order to further improve the performance. The analysis shows that uniformly distributed phase difference (between the host signal and the watermark) provides maximum advantage. This property is verified through experimentation over a variety of audio signals. In the second part, the correlated nature of audio signals is identified as a potential threat to reliable blind watermark detection, and audio pre-whitening methods are suggested as a possible remedy. A direct deterministic whitening (DDW) scheme is derived, from the frequency domain analysis of the time domain correlation process. Our experimental studies reveal that, the Savitzky-Golay Whitening (SGW), which is otherwise inferior to DDW technique, performs better when the audio signal is predominantly low pass. The novelty of this work lies in exploiting the complementary nature of the two whitening techniques and combining them to obtain a hybrid whitening (HbW) scheme. In the hybrid scheme the DDW and SGW techniques are selectively applied, based on short time spectral characteristics of the audio signal. The hybrid scheme extends the reliability of watermark detection to a wider range of audio signals. We also discuss enhancements to the HbW technique for robustness to temporal offsets and filtering. Robustness of SS watermark blind detection, with hybrid whitening, is determined through a set of experiments and the results are presented. It is seen that the watermarking scheme is robust to common signal processing operations such as additive noise, filtering, lossy compression, etc.
505

New Ways of Seeing: Examining Musuem Accessibility for Visitors with Vision Impairments

Sbarra, Wendy M 12 August 2012 (has links)
While I have always loved to go to the art museum I have often found it difficult to convince friends and family to go with me. It seems to be a particularly daunting task for visitors with disabilities and specifically those with vision impairments. This study surveys the accessibility of the programming for visitors with visual impairments at 25 art museums in the United States of America and how they communicate that information to potential visitors. It highlights museums that go beyond what is required by the Americans with Disabilities Act and create programming that is enjoyable for all. This study will be a reference to create a more enjoyable experience for all.
506

Die Zukunft Barrierefrei – Blindenbüchereien als Schrittmacher der digitalen Revolution?!

Kahlisch, Thomas, Dobroschke, Julia, Puder, Nicole 23 June 2010 (has links) (PDF)
Die in MEDIBUS organisierten Blindenbüchereien sehen sich als Partner der kommerziellen Verlagswelt und nicht als deren Konkurrenten. Die sehr geringen Auflagenhöhen und die speziellen Anforderungen bei der Aufbereitung von Literatur in Brailleschrift und Großdruck wecken in aller Regel nur wenig verlegerisches Interesse. Die wachsende Auswahl an mobilen Endgeräten, Medienkonvergenz und Diversifikation von Angeboten sind Chancen der digitalen Revolution, die es ermöglichen, auch Menschen mit speziellen Bedürfnissen zeitnah und in adäquater Qualität Wissen zugänglich zu machen. libreka! und die DZB kooperieren im Projekt „Leibniz – Sach- und Fachbuchaufbereitung für Blinde und Sehbehinderte“, um PDF- und Satzdaten zu verarbeiten und deren digitale Verbreitung sowohl für sehende als auch für nichtsehende Leserinnen und Leser zu forcieren. DAISY-Standards und -Technologien sind dabei der Schlüssel zum Erfolg.
507

Increasing availability of non-fiction publications in Braille, DAISY and large print

Kahlisch, Thomas 23 June 2010 (has links) (PDF)
In this presentation, various projects at DZB will be described, concerning various collaborations with publishing houses and Libreka! – an online platform of the German association of publishers “Börsenverein des Deutschen Buchhandels”, to improve the workflow of transformation of typesetting data into the DAISY 3 format. By developing adaptive content processing facilities, this data can be used to increase the availability of publications in Braille, DAISY and large Print.
508

Sparsity Motivated Auditory Wavelet Representation and Blind Deconvolution

Adiga, Aniruddha January 2017 (has links) (PDF)
In many scenarios, events such as singularities and transients that carry important information about a signal undergo spreading during acquisition or transmission and it is important to localize the events. For example, edges in an image, point sources in a microscopy or astronomical image are blurred by the point-spread function (PSF) of the acquisition system, while in a speech signal, the epochs corresponding to glottal closure instants are shaped by the vocal tract response. Such events can be extracted with the help of techniques that promote sparsity, which enables separation of the smooth components from the transient ones. In this thesis, we consider development of such sparsity promoting techniques. The contributions of the thesis are three-fold: (i) an auditory-motivated continuous wavelet design and representation, which helps identify singularities; (ii) a sparsity-driven deconvolution technique; and (iii) a sparsity-driven deconvolution technique for reconstruction of nite-rate-of-innovation (FRI) signals. We use the speech signal for illustrating the performance of the techniques in the first two parts and super-resolution microscopy (2-D) for the third part. In the rst part, we develop a continuous wavelet transform (CWT) starting from an auditory motivation. Wavelet analysis provides good time and frequency localization, which has made it a popular tool for time-frequency analysis of signals. The CWT is a multiresolution analysis tool that involves decomposition of a signal using a constant-Q wavelet filterbank, akin to the time-frequency analysis performed by basilar membrane in the peripheral human auditory system. This connection motivated us to develop wavelets that possess auditory localization capabilities. Gammatone functions are extensively used in the modeling of the basilar membrane, but the non-zero average of the functions poses a hurdle. We construct bona de wavelets from the Gammatone function called Gammatone wavelets and analyze their properties such as admissibility, time-bandwidth product, vanishing moments, etc.. Of particular interest is the vanishing moments property, which enables the wavelet to suppress smooth regions in a signal leading to sparsi cation. We show how this property of the Gammatone wavelets coupled with multiresolution analysis could be employed for singularity and transient detection. Using these wavelets, we also construct equivalent lterbank models and obtain cepstral feature vectors out of such a representation. We show that the Gammatone wavelet cepstral coefficients (GWCC) are effective for robust speech recognition compared with mel-frequency cepstral coefficients (MFCC). In the second part, we consider the problem of sparse blind deconvolution (SBD) starting from a signal obtained as the convolution of an unknown PSF and a sparse excitation. The BD problem is ill-posed and the goal is to employ sparsity to come up with an accurate solution. We formulate the SBD problem within a Bayesian framework. The estimation of lter and excitation involves optimization of a cost function that consists of an `2 data- fidelity term and an `p-norm (p 2 [0; 1]) regularizer, as the sparsity promoting prior. Since the `p-norm is not differentiable at the origin, we consider a smoothed version of the `p-norm as a proxy in the optimization. Apart from the regularizer being non-convex, the data term is also non-convex in the filter and excitation as they are both unknown. We optimize the non-convex cost using an alternating minimization strategy, and develop an alternating `p `2 projections algorithm (ALPA). We demonstrate convergence of the iterative algorithm and analyze in detail the role of the pseudo-inverse solution as an initialization for the ALPA and provide probabilistic bounds on its accuracy considering the presence of noise and the condition number of the linear system of equations. We also consider the case of bounded noise and derive tight tail bounds using the Hoe ding inequality. As an application, we consider the problem of blind deconvolution of speech signals. In the linear model for speech production, voiced speech is assumed to be the result of a quasi-periodic impulse train exciting a vocal-tract lter. The locations of the impulses or epochs indicate the glottal closure instants and the spacing between them the pitch. Hence, the excitation in the case of voiced speech is sparse and its deconvolution from the vocal-tract filter is posed as a SBD problem. We employ ALPA for SBD and show that excitation obtained is sparser than the excitations obtained using sparse linear prediction, smoothed `1=`2 sparse blind deconvolution algorithm, and majorization-minimization-based sparse deconvolution techniques. We also consider the problem of epoch estimation and show that epochs estimated by ALPA in both clean and noisy conditions are closer to the instants indicated by the electroglottograph when with to the estimates provided by the zero-frequency ltering technique, which is the state-of-the-art epoch estimation technique. In the third part, we consider the problem of deconvolution of a specific class of continuous-time signals called nite-rate-of-innovation (FRI) signals, which are not bandlimited, but specified by a nite number of parameters over an observation interval. The signal is assumed to be a linear combination of delayed versions of a prototypical pulse. The reconstruction problem is posed as a 2-D SBD problem. The kernel is assumed to have a known form but with unknown parameters. Given the sampled version of the FRI signal, the delays quantized to the nearest point on the sampling grid are rst estimated using proximal-operator-based alternating `p `2 algorithm (ALPAprox), and then super-resolved to obtain o -grid (O. G.) estimates using gradient-descent optimization. The overall technique is termed OG-ALPAprox. We show application of OG-ALPAprox to a particular modality of super-resolution microscopy (SRM), called stochastic optical reconstruction microscopy (STORM). The resolution of the traditional optical microscope is limited by di raction and is termed as Abbe's limit. The goal of SRM is to engineer the optical imaging system to resolve structures in specimens, such as proteins, whose dimensions are smaller than the di raction limit. The specimen to be imaged is tagged or labeled with light-emitting or uorescent chemical compounds called uorophores. These compounds speci cally bind to proteins and exhibit uorescence upon excitation. The uorophores are assumed to be point sources and the light emitted by them undergo spreading due to di raction. STORM employs a sequential approach, wherein each step only a few uorophores are randomly excited and the image is captured by a sensor array. The obtained image is di raction-limited, however, the separation between the uorophores allows for localizing the point sources with high precision. The localization is performed using Gaussian peak- tting. This process of random excitation coupled with localization is performed sequentially and subsequently consolidated to obtain a high-resolution image. We pose the localization as a SBD problem and employ OG-ALPAprox to estimate the locations. We also report comparisons with the de facto standard Gaussian peak- tting algorithm and show that the statistical performance is superior. Experimental results on real data show that the reconstruction quality is on par with the Gaussian peak- tting.
509

Calibra??o cega de receptores cinco-portas baseada em separa??o cega de fontes

Vidal, Francisco Jos? Targino 24 May 2013 (has links)
Made available in DSpace on 2014-12-17T14:55:16Z (GMT). No. of bitstreams: 1 FranciscoJTV_TESE.pdf: 16694617 bytes, checksum: 98c04bab1f2a3180ba8bd87b03174888 (MD5) Previous issue date: 2013-05-24 / The exponential growth in the applications of radio frequency (RF) is accompanied by great challenges as more efficient use of spectrum as in the design of new architectures for multi-standard receivers or software defined radio (SDR) . The key challenge in designing architecture of the software defined radio is the implementation of a wide-band receiver, reconfigurable, low cost, low power consumption, higher level of integration and flexibility. As a new solution of SDR design, a direct demodulator architecture, based on fiveport technology, or multi-port demodulator, has been proposed. However, the use of the five-port as a direct-conversion receiver requires an I/Q calibration (or regeneration) procedure in order to generate the in-phase (I) and quadrature (Q) components of the transmitted baseband signal. In this work, we propose to evaluate the performance of a blind calibration technique without additional knowledge about training or pilot sequences of the transmitted signal based on independent component analysis for the regeneration of I/Q five-port downconversion, by exploiting the information on the statistical properties of the three output signals / Estudos recentes apontam que o aumento nas aplica??es de r?dio frequ?ncia (RF) vem acompanhado por grandes desafios tanto no uso eficiente do espectro eletromagn?tico quanto no projeto de novas arquiteturas para receptores multi-padr?o, ou r?dio definidos por software (RDS). O principal desafio da arquitetura f?sica de um RDS ? a implementa??o de um receptor banda-larga com caracter?sticas de baixo custo, baixo consumo, maior grau de integra??o e flexibilidade. A arquitetura homodina, baseada na tecnologia cinco-portas, surge como uma alternativa para aplica??es em r?dio definidos por software. No entanto, a regenera??o das componentes em fase e quadratura, no receptor cinco-portas, comumente denominada de calibra??o, constitui um dos maiores desafios na aplica??o dessa tecnologia. Os m?todos de calibra??o, propostos na literatura, normalmente baseiam-se no conhecimento do modelo matem?tico do circuito, em que o mesmo ? calibrado previamente (off-line), para um tipo de sinal com caracter?sticas espec?ficas ou em tempo real, com base no conhecimento da sequ?ncia de aprendizagem e do tipo de modula??o. Nesse trabalho, ? apresentado uma proposta de regenera??o cega dessas componentes, para um receptor homodino cinco-portas, utilizando a abordagem denominada Separa??o Cega de Fontes (an?lise de componentes independentes - ICA), que explora as caracter?sticas estat?sticas dos tr?s sinais de sa?da do receptor cinco-portas. A valida??o dessa abordagem ? realizada por meio de simula??o e de resultados experimentais obtidos para o receptor cinco portas implementado em tecnologia de microfita
510

O processo educacional do cego em Aracaju (1950-1970)

Nunes, Patrícia Matos Souza 29 May 2013 (has links)
Doing an analysis of the circumstance about the education of disabled person, we identify mechanisms of segregation and exclusion promoted by welfares and philanthropic politics. Before addition, the objective of this study is to understand how the educational process of blind in Aracaju started. As theoretical basis, this research is based in the assumptions of Cultural History because this perspective shows a preoccupation with anonymous populations, their modes of living, feeling and thinking. The sources used were Official Documents, Records, magazines, newspapers, laws, testimonials and other. These different registers were collected in file located in Aracaju and Rio de Janeiro. We have searched on the file of the Metropolitan Archdiocese of Aracaju, in the Historical and Geographic Institute, Epifânio Dórea Library in Aracaju; and in the file of the Benjamin Constant Institute, at Rio de Janeiro. The testimonials were collected through semi structured interview with the first teachers who worked with the blind education in Aracaju. The timeframe comprises the 50-70 decades in the twenty century, since this time was characterized by the beginning of the institution that provided education treatment to the disabled people. The first schools to blind were the Escola de Reabilitação dos Cegos de Aracaju, founded by the Bishop Dom Fernando Gomes and the Escola de Cegos Lyon s Club that worked at the Centro de Reabilitação Ninota Garcia . The main categories of analisys used were: scholar culture, scholar material culture, representation and appropriation. We hope, with this investigation, to identify elements of the education practices used with blind in Aracaju during 1950-1970. / Ao fazermos uma análise das circunstâncias que cercam a educação da pessoa com deficiência, identificam-se mecanismos de segregação e exclusão fomentados por políticas assistencialistas e filantrópicas. Diante disso, o presente estudo tem como objetivo compreender como se deu o processo educacional do cego em Aracaju. Como base teóricometodológica, a pesquisa se fundamenta nos pressupostos da História Cultural, uma vez que essa perspectiva apresenta uma preocupação com as massas anônimas, seus modos de viver, sentir e pensar. As fontes utilizadas foram: documentos oficiais, Atas, revistas, jornais legislação e depoimentos, dentre outros. Os diferentes registros citados foram coletados em arquivos localizados em Aracaju e no Rio de Janeiro. Pesquisamos no Arquivo da Arquidiocese Metropolitana de Aracaju, no Instituto Histórico e Geográfico de Sergipe, na Biblioteca Epifânio Dória, em Aracaju; e no Arquivo Instituto Benjamin Constant, no Rio de Janeiro. Os depoimentos foram coletados através de entrevistas semiestruturadas com as professoras pioneiras que atuaram na educação de cego em Aracaju. O marco temporal compreende as décadas de 1950, 1960 e 1970 do século XX, uma vez que este período foi marcado pelo surgimento das instituições que prestaram atendimento educacional à pessoa com deficiência visual. As primeiras escolas para os cegos foram a Escola de Reabilitação dos Cegos de Aracaju, fundada pelo Bispo Dom Fernando Gomes e a Escola de Cegos Lyon s Club que funcionou no Centro de Reabilitação Ninota Garcia. As principais categorias de análise utilizadas foram: cultura escolar, cultura material escolar, representação e apropriação. Espera-se, com esta investigação, elucidar elementos das práticas educativas utilizadas com os cegos em Aracaju, no período de 1950-1970.

Page generated in 0.0331 seconds