This dissertation introduces a novel automated book reader as an assistive technology tool for persons with blindness. The literature shows extensive work in the area of optical character recognition, but the current methodologies available for the automated reading of books or bound volumes remain inadequate and are severely constrained during document scanning or image acquisition processes. The goal of the book reader design is to automate and simplify the task of reading a book while providing a user-friendly environment with a realistic but affordable system design. This design responds to the main concerns of (a) providing a method of image acquisition that maintains the integrity of the source (b) overcoming optical character recognition errors created by inherent imaging issues such as curvature effects and barrel distortion, and (c) determining a suitable method for accurate recognition of characters that yields an interface with the ability to read from any open book with a high reading accuracy nearing 98%. This research endeavor focuses in its initial aim on the development of an assistive technology tool to help persons with blindness in the reading of books and other bound volumes. But its secondary and broader aim is to also find in this design the perfect platform for the digitization process of bound documentation in line with the mission of the Open Content Alliance (OCA), a nonprofit Alliance at making reading materials available in digital form. The theoretical perspective of this research relates to the mathematical developments that are made in order to resolve both the inherent distortions due to the properties of the camera lens and the anticipated distortions of the changing page curvature as one leafs through the book. This is evidenced by the significant increase of the recognition rate of characters and a high accuracy read-out through text to speech processing. This reasonably priced interface with its high performance results and its compatibility to any computer or laptop through universal serial bus connectors extends greatly the prospects for universal accessibility to documentation.

Basic research on expectancy effects suggests that investigative interviewers with pre-conceived notions about a crime may negatively influence the interview process in meaningful ways, yet many interviewing protocols recommend that interviewers review all available information prior to conducting their interviews. Previous research suggests that interviewers with no pre-interview knowledge elicit more detailed and accurate accounts than their informed counterparts (Cantlon, et al., 1996; Rivard et al., under review). The current study investigated whether (a) the benefit of blind versus informed interviewing is moderated by cautionary interviewer instructions to avoid suggestive questions and (b) whether any possible effects of pre-interview information extend beyond the immediate context of the forensic interview. Paired participants (N = 584) were assigned randomly either to the role of interviewer or witness. Witnesses viewed a mock crime video and were interviewed one week later by an interviewer who received either correct, incorrect, or no information about the crime event. Half of the interviewers were assigned randomly to receive additional instructions to avoid suggestive questions. All participants returned 1 week after the interview to recall the crime video (for the witness) or the information recalled by the witness during the interview (for the interviewer). All interviews and delayed recall measures were scored for the quantity and accuracy of information reported. Results replicate earlier findings that blind interviewers elicit more information from witnesses, without a decrease in accuracy rate. However instructions to avoid suggestive questions did not moderate the effect of blind versus informed interviewing on witness recall during the interview. Results further demonstrate that the effects of blind versus non-blind interviewing may extend beyond the immediate context of the interview to a later recall attempt. With instructions to avoid suggestive questions, witnesses of blind interviewers were more accurate than witnesses of incorrectly informed interviewers when recalling the event 1 week later. In addition, blind interviewers had more accurate memories for the witnesses’ account of the event during the interview compared to non-blind interviewers.

Since 1994, the South African Government has formulated various policies in an attempt to redress the previous political, economic and social imbalances within the country. The majority of the policies have focused on empowering previously disadvantaged groups including people with disabilities. Despite the interventions, literature reviewed reflects that there is very little progress made with regard to empowerment of people with disabilities in the employment sector. The study seeks to explore and identify factors that affect people with visual disabilities in the employment sector. The researcher used a qualitative approach to investigate the perceptions of people with visual disabilities through conducting focus groups interviews with participants that were recruited using a purposive sampling approach. A total of four groups from Pretoria have been used to draw findings for the research study. During the focus group discussions, a semi structured interview guide was used to generate more in‐depth interpretations from the participants and data was analysed using Tesch’s (1990) framework that is described in Creswell (2003). The findings of the research revealed that people with visual disabilities still have problems in accessing and retaining employment despite the South African favourable legislation. Dominating among the factors that are viewed by the participants to hinder their employability are societal negatives attitudes which include unequal treatment, discrimination when they seek employment, belittling and disregard by employers, coworkers and the society at large. There are also a number of factors that were perceived as barriers to job seekers with visual disabilities which include inaccessible advertising media for vacancies, inaccessible transports systems, inaccessible education and training and lack of funded positions suited for people with visual disabilities.

Freeform optics provide excellent performance for a wide variety of applications. However, obtaining an accurate freeform surface measurement is highly challenging due to its large aspheric/freeform departure. It has been proven that SCOTS (Software Configurable Optical Test System), an advanced deflectometry system developed at the University of Arizona, can measure the departure of a freeform surface from the desired shape with nanometer accuracy. Here, a new data processing technique was used to measure a freeform surface without any prior knowledge of the shape of the surface. Knowing only the geometry of one point on the test surface, this method can take a blind measurement of a freeform surface and arrive at the true surface through iterative construction.

This work contains a phenomenological analysis of blindness, providing a basis for the evaluation of rehabilitation practice in South Africa and the formulation of future objectives in the field. Stereotypes of blindness associated with the perspectives of consumerism, scientific research, and social casework are analysed. Theories of blindness proposed by Braverman, Carroll, Monbeck, Foulke, Jernigan, and Scott are critically examined. The findings give substance to the claim that professional workers with the blind are guided in their attitudes and actions by images and meanings originating from these sources. All such preconceptions are rejected in favour of a description of blindness in terms of actual experience. An in-depth study of experience reveals how the nature of perception determines the blind person's relationship with the physical environment, with other people, and with the welfare system. In each sphere limitations arise which are overcome by specific responses and appropriate techniques. These observations lead to the formulation of a set of basic principles of rehabilitation, stressing the importance of individualization, self-reliance, assertiveness, versatility, and a personal interpretation of blindness. The relevance of traditional modalities is explained, while the need to expand rehabilitation teaching to include assertive skills training and various types of vocational instruction is emphasized. Current rehabilitation practice in South Africa is evaluated, comparisons being drawn with programmes offered by Beit Halochem in Tel Aviv, Arkansas Enterprises for the Blind, and the Center for Independent Living of the New York Infirmary. South African training is characterized as fostering the independence of the individual. Negative features are the lack of an effective delivery system and failure to meet the priority needs of certain groups. This prepares the way for a case study in which the redevelopment of rehabilitation services for the blind in South Africa .is discussed, beginning with the establishment of a new national rehabilitation centre. Amongst other matters, the study deals with negotiations to circumvent restrictive legislation, funding through a system of corporate sponsorship, and purposeful architectural design. The rehabilitation centre is viewed as the first component of a broader strategy to provide rehabilitation training to all blind people in South Africa, incorporating national, urban, rural, and specialized services. The successful implementation of any action plan will require the participation of blind people themselves by way of a disability rights movement. Finally, attention is focused on the effect of South African racial policies on welfare work. The principle of equal opportunity cannot be practised under present legislation.

Le codage réseau est un paradigme qui permet une utilisation efficace du réseau. Il maximise le débit dans un réseau multi-saut en multicast et réduit le retard. Dans cette thèse, nous concentrons notre attention sur l’intégration du codage réseau aux applications multimédias, et en particulier aux systèmes avancès qui fournissent un service vidéo amélioré pour les utilisateurs. Nos contributions concernent plusieurs scénarios : un cadre de fonctions efficace pour la transmission de flux en directe qui utilise à la fois le codage réseau et le codage par description multiple, une nouvelle stratégie de transmission pour les réseaux sans fil avec perte qui garantit un compromis entre la résilience vis-à-vis des perte et la reduction du retard sur la base d’une optimisation débit-distorsion de l'ordonnancement des images vidéo, que nous avons également étendu au cas du streaming multi-vue interactive, un système replication sociale distribuée qui, en utilisant le réseau codage en relation et la connaissance des préférences des utilisateurs en termes de vue, est en mesure de sélectionner un schéma de réplication capable de fournir une vidéo de haute qualité en accédant seulement aux autres membres du groupe social, sans encourir le coût d’accès associé à une connexion à un serveur central et sans échanger des larges tables de métadonnées pour tenir trace des éléments répliqués, et, finalement, une étude sur l’utilisation de techniques de séparation aveugle de source -pour réduire l’overhead encouru par les schémas de codage réseau- basé sur des techniques de détection d’erreur telles que le codage de parité et la génération de message digest. / Network coding is a paradigm that allows an efficient use of the capacity of communication networks. It maximizes the throughput in a multi-hop multicast communication and reduces the delay. In this thesis, we focus our attention to the integration of the network coding framework to multimedia applications, and in particular to advanced systems that provide enhanced video services to the users. Our contributions concern several instances of advanced multimedia communications: an efficient framework for transmission of a live stream making joint use of network coding and multiple description coding; a novel transmission strategy for lossy wireless networks that guarantees a trade-off between loss resilience and short delay based on a rate-distortion optimized scheduling of the video frames, that we also extended to the case of interactive multi-view streaming; a distributed social caching system that, using network coding in conjunction with the knowledge of the users' preferences in terms of views, is able to select a replication scheme such that to provide a high video quality by accessing only other members of the social group without incurring the access cost associated with a connection to a central server and without exchanging large tables of metadata to keep track of the replicated parts; and, finally, a study on using blind source separation techniques to reduce the overhead incurred by network coding schemes based on error-detecting techniques such as parity coding and message digest generation. All our contributions are aimed at using network coding to enhance the quality of video transmission in terms of distortion and delay perceived

The purpose of this investigation was to determine if a significant difference exists between oral stereognosis skills of blind and sighted children. The possibility of a relationship between oral stereognosis and articulation was also explored in both the sighted and blind populations. A group of twenty-four blind and a group of twenty four sighted subjects between the ages of seven and twenty were divided into subgroups of those having normal speech and those with defective articulation . There were twelve subjects in each subgroup . A 20-item test of oral stereognosis (NIDR forms) was administered to each subject and error scores taken. Results of the study indicate that no significant difference exists between the oral stereognosis abilities of sighted and blind subjects. A significant difference was found to exlst at the .01 level between oral stereognosis scores of normal speakers and articulatory impaired speakers. This difference was also found to be significant between the blind subgroups but not between the sighted subgroups.

The purposes of this study were (1) to learn how many persons who were members of the Church of Jesus Christ of Latter-day Saints were blind, (2) to determine the social and economic conditions of these blind members, and (3) to learn what the Church of Jesus Christ of Latter-day Saints has done to promote employment of blind members through its Welfare Program, and how this was accomplished.

No description available.

<p> The focus of this thesis is on the utilization of the sparsity concept in solving some challenging problems, e.g., finding a unique solution to the under-determined linear system of equations in which the number of equations is less than the number of unknowns. This concept is extended to the problem of solving the under-determined blind source separation (BSS) problem in which the number of source signals is greater than the number of sensors and both the mixing matrix and the source signals are unknowns. In this respect we study three problems: </p> <p> 1. Developing some algorithms for solving the under-determined linear system of equations for the case of a sparse solution vector. In this thesis we develop a new methodology for minimizing a class of non-convex (concave on the non-negative orthant) functions for solving the aforementioned problem. The proposed technique is based on locally replacing the original objective function by a quadratic convex function which is easily minimized. For a certain selection of the convex objective function, the existing class of algorithms called Iterative Re-weighted Least Squares (IRLS) can be derived from the proposed methodology. Thus the proposed algorithms are a generalization and unification of the previous methods. In this thesis we also propose a convex objective function that produces an algorithm that can converge to a sparse solution vector in significantly fewer iterations than the IRLS algorithms.</p> <p> 2. Solving the under-determined BSS problem by developing new clustering algorithms for estimating the mixing matrix. The under-determined BSS problem is usually solved by following a two-step approach, in which the mixing matrix is estimated in the first step, then the sources are estimated in the second step. For the case of sparse sources, the mixing matrix is usually estimated by clustering the columns of the observation matrix. In this thesis we develop three novel clustering algorithms that can efficiently estimate the mixing matrix, as well as the number of sources, which is usually unknown. Numerical simulations verify the efficiency of the proposed algorithms compared to some well known algorithms that are usually used for solving the same problem.</p> <p> 3. Extraction of a desired source signal from a linear mixture of hidden sources when prior information is available about the desired source signal. There are many situations in which one is interested in extracting a specific source signal. The a priori available information about the desired source signal could be temporal, spatial, or both. In this thesis we develop new algorithms for extracting a desired sparse source signal from a linear mixture of hidden sources. The information available about the desired source signal, as well as its sparsity, are incorporated in an optimization problem for extracting this source signal. Four different algorithms have been developed for solving this problem. Numerical simulations show that the proposed algorithms can be used successfully for removing different kind of artifacts from real electroencephalographic (EEG) data and for estimating the event related potential (ERP) signal from synthesized EEG data.</p> / Thesis / Doctor of Philosophy (PhD)