abstract: Societal infrastructure is built with vision at the forefront of daily life. For those with severe visual impairments, this creates countless barriers to the participation and enjoyment of life’s opportunities. Technological progress has been both a blessing and a curse in this regard. Digital text together with screen readers and refreshable Braille displays have made whole libraries readily accessible and rideshare tech has made independent mobility more attainable. Simultaneously, screen-based interactions and experiences have only grown in pervasiveness and importance, precluding many of those with visual impairments. Sensory Substituion, the process of substituting an unavailable modality with another one, has shown promise as an alternative to accomodation, but in recent years meaningful strides in Sensory Substitution for vision have declined in frequency. Given recent advances in Computer Vision, this stagnation is especially disconcerting. Designing Sensory Substitution Devices (SSDs) for vision for use in interactive settings that leverage modern Computer Vision techniques presents a variety of challenges including perceptual bandwidth, human-computer-interaction, and person-centered machine learning considerations. To surmount these barriers an approach called Per- sonal Foveated Haptic Gaze (PFHG), is introduced. PFHG consists of two primary components: a human visual system inspired interaction paradigm that is intuitive and flexible enough to generalize to a variety of applications called Foveated Haptic Gaze (FHG), and a person-centered learning component to address the expressivity limitations of most SSDs. This component is called One-Shot Object Detection by Data Augmentation (1SODDA), a one-shot object detection approach that allows a user to specify the objects they are interested in locating visually and with minimal effort realizing an object detection model that does so effectively. The Personal Foveated Haptic Gaze framework was realized in a virtual and real- world application: playing a 3D, interactive, first person video game (DOOM) and finding user-specified real-world objects. User study results found Foveated Haptic Gaze to be an effective and intuitive interface for interacting with dynamic visual world using solely haptics. Additionally, 1SODDA achieves competitive performance among few-shot object detection methods and high-framerate many-shot object de- tectors. The combination of which paves the way for modern Sensory Substitution Devices for vision. / Dissertation/Thesis / Doctoral Dissertation Computer Engineering 2020

Avec le vieillissement démographique, le nombre de personnes âgées dépendantes augmente et les proches (ou "tierces personnes") sont de plus en plus sollicités à leur côté. Dans une visée de santé publique, il importe d'étudier la place des tierces personnes dans le vieillissement et la relation entre dépendance et accumulation de facteurs de risque accessibles à la prévention.Le premier axe de cette thèse s'intéresse à l'intervention des tierces personnes dans les études de cohorte avançant en âge. Le deuxième axe consiste à analyser l'association entre la dépendance et l'accumulation de déficits sensoriels ou de comportements de santé.Cette thèse se base sur les données des femmes de la cohorte E3Nnées entre 1925 et 1930 : celles auto-rapportées et celles recueillies auprès d'une tierce personne. La dépendance est définie comme la présence d'une limitation dans au moins une des huit activités de l'échelle des activités instrumentales de la vie quotidienne (IADL).Les tierces personnes corroborent globalement la perception des personnes âgées concernant leur capacité à réaliser les IADL, étayant ainsi l'intérêt de leur implication dans les études épidémiologiques portant sur le vieillissement. Nous montrons également qu'un double déficit sensoriel est associé à un risque accru de survenue de la dépendance à court terme. De plus, le non-respect des recommandations concernant cinq comportements de santé était associé à une augmentation du risque de dépendance une dizaine d'année plus tard, selon un schéma cumulatif.Cette thèse contribue à valoriser la place des tierces personnes dans les études épidémiologiques et à améliorer les connaissances sur les facteurs de risque modifiables de la dépendance. Elle ouvre des pistes d'actions ciblées permettant d'améliorer la qualité de vie des personnes âgées tout en augmentant leur durée de vie sans incapacité. / The number of people living with disabilities is rising with the ageing of the population, leading to an increased need in proxy' help (or from "third partie"). Preventive approaches to delay disability or increase disability-free life expectancy are needed. In that respect, it is essential to study proxies'role in ageing, to identify risk factors of disability, and to analyze the effect of combinations of risk factors on risk of disability.The first aim of this PhD thesis was to study the contribution of proxies in cohorts of older people. The second aim was to analyze the association between disability and cumulative sensory impairments or health behaviours.The study population consisted in a subpopulation of the E3N cohort of women born between 1925 and 1930. Data were self-reported and/or reported by a proxy. Disability was defined as a limitation in at least one of the eight instrumental activities of daily living (IADL) scale.Results supported the interest of proxy involvement in epidemiological studies, particularly in those dealing with ageing. Indeed, most proxies corroborated the perception of the elderly women about their ability to perform IADL. In the study of risk factors of disability, having a dual sensory impairment was associated with higher short-term incidence of disability. Moreover, not adhering to the recommendations in the five studied health behaviours was associated with an increased risk of disability ten years later, in a dose-dependent manner.This work contributes to highlight the usefulness of proxies in large epidemiological studies, and to enhance knowledge about risk factors of disability. It suggests tracks of targeted actions to improve the quality of life of older people, and to increase their disability-free life duration.

Hardware impairments (HWIs) impose a huge challenge on modern wireless commu- nication systems owing to the characteristics like compactness, least complexity, cost ef- fectiveness and high energy efficiency. Numerous techniques are implemented to minimize the detrimental effects of these HWIs ,however, the residual HWIs may still appear as an additive distortion, multiplicative interference, or an aggregate of both. Numerous studies have commenced efforts to model one or the other forms of hardware impairments in the ra- dio frequency (RF) transceivers. Many presented the widely linear model for in-phase and quadrature imbalance (IQI) but failed to recognize the impropriety induced in the system because of the self-interfering signals. Therefore, we have presented not only a rigorous ag- gregate impairment model along with its complete impropriety statistical characterization but also the appropriate performance analysis to quantify their degradation effects. Lat- est advances have endorsed the superiority of incorporating more generalized impropriety phenomenon as opposed to conventional propriety. In this backdrop, we propose the improper Gaussian signaling (IGS) to mitigate the drastic impact of HWIs and improve the system performance in terms of achievable rate and outage probability. Recent contributions have advocated the employment of IGS over traditional proper Gaussian signaling (PGS) in various interference limited scenarios even in the absence of any improper noise/interference. It is pertaining to the additional degree of freedom (DoF) offered by IGS, which can be optimized to reap maximum benefits. This reduced-entropy signaling is the preferred choice to pose minimal interference to a legitimate network yielding another mechanism to tackle undesired interference. Evidently, the incorporation of both inherent and induced impropriety characteristics is critical for effective utilization. Most of the recent research revolves around the theoretical analysis and advantages of improper signaling with minimal focus on its practical realization. We bridge this gap by adopting and optimizing asymmetric signaling (AS) which is the finite discrete implemen- tation of the improper signaling. We propose the design of both structural and stochastic shaping to realize AS. Structural shaping involves geometric shaping (GS) of the symbol constellation using some rotation and translation matrices. Whereas, stochastic shaping as- signs non-uniform prior probabilities to the symbols. Furthermore, hybrid shaping (HS) is also proposed to reap the gains of both geometric and probabilistic shaping. AS is proven superior to the conventional M-ary symmetric signaling in all of its forms. To this end, probabilistic shaping (PS) demonstrates the best trade-off between the performance en- hancement and added complexity. This research motivates further investigation for the utilization of impropriety concepts in the upcoming generations of wireless communications. It opens new paradigms in inter- ference management and another dimension in the signal space. Besides communications, the impropriety characterization has also revealed numerous applications in the fields of medicine, acoustics, geology, oceanography, economics, bioinformatics, forensics, image processing, computer vision, and power grids.

Background: Most of the neurocognitive research in Posttraumatic Stress Disorder (PTSD) thus far focused on impairment in learning and memory, neglecting the impact of PTSD on executive functioning processes. Therefore, this study specifically aims to investigate the impact of PTSD on frontal lobe executive functioning. Given the high prevalence rate for traumatic event exposure in South Africa, this study provides important findings on the role intact executive functioning plays in all areas of daily functioning, including the maintenance of good mental and physical health. Methods: Executive functions were assessed using an Executive Functioning Battery consisting of the three subtests of the Delis Kaplan Executive Functioning System (e.g., Trail Making Test, Colour-Word Interference Test, and Tower Test), as well as the Executive Functioning Index. The study sample consisted of 88 adult South African citizens who were divided into two groups (PTSD+; n = 44; PTSD–; n = 44) with different levels of trauma exposure. Results: PTSD was linked with impairment in executive functioning domains such as attention, cognitive flexibility, inhibition, working memory, and planning. Important gender differences were also reported in terms of empathy and organisation. In addition, education also appeared to affect frontal lobe executive functioning differently. Conclusions: The data suggest that overall, PTSD impaired executive functioning processes. It is therefore critical that assessment of executive functioning form part of a comprehensive treatment plan for individuals diagnosed with PTSD. / Mini Dissertation (MA)--University of Pretoria, 2019. / Psychology / MA / Unrestricted

Next generation of wireless communication mostly relies on multiple-input multipleoutput (MIMO) configuration and full-duplex relaying to improve data-rates, spectrale efficiency, spatial-multiplexing, quality-of-service and energy-efficiency etc. However, multiple radio frequency (RF) transceivers in MIMO system and multi-hops in relay networks, accumulate transceiver impairments, rendering an unacceptable system performance. Majority of the technical contributions either assume ideal hardware or inappropriately model hardware impairments which often induce misleading results especially for high data-rate communication systems. We propose statistical mathematical modeling of various hardware impairment (HWI) to characterize their deteriorating effects on the information signal. In addition, we model the aggregate HWI as improper Gaussian signaling (IGS), to fully characterize their asymmetric properties and the self-interfering signal attribute under I/Q imbalance. The proposed model encourages to adopt asymmetric transmission scheme, as opposed to traditional symmetric signaling. First, we present statistical baseband equivalent mathematical models for general MIMO system and two special scenarios of receive and transmit diversity systems under HWI. Then, we express their achievable rate under PGS and IGS transmit schemes. Moreover, we tune the IGS statistical characteristics to maximize the achievable rate. We also present optimal beam-forming/pre-coding and receive combiner vector for multiple-input single-output (MISO) and single-input multiple output (SIMO) systems, which lead to SDNR maximization. Moreover, we propose an adaptive scheme to switch between maximal IGS (MIGS) and PGS transmission based on the described conditions to reduce computational overhead. Subsequently, two case studies are presented. 1) Outage analysis has been carried out for SIMO, under transceiver distortion noise, for two diversity combining schemes 2) The benefits of employing IGS is investigated in full duplex relaying (FDR) suffering from two types of interference, the residual self-interference (RSI) and I/Q distortions. We further optimize the pseudo-variance to compensate the interference impact and improve end-to-end achievable rate. Finally, we validate the analytic expressions through simulation results, to quantify the performance degradation in the absence of ideal transceivers and the gain reaped from adopting IGS scheme compared with PGS scheme.

Syfte: Syftet med studien var att undersöka arbetsterapeuters erfarenheter av att arbeta med fritidsaktiviteter för barn och ungdomar som lever med funktionsnedsättningar inom barn- och ungdomspsykiatrin och habiliteringen. Metod: Studien genomfördes som en kvalitativ intervjustudie. Sju semistrukturerade intervjuer utfördes via telefon och Skype med yrkesverksamma arbetsterapeuter med erfarenheter av att arbeta med barn och ungdomar med funktionsnedsättningar inom barn- och ungdomshabiliteringen (HAB) samt barn- och ungdomspsykiatrin (BUP). Vid analys av intervjuerna användes en kvalitativ innehållsanalys. Resultat: Det framgick i resultatet att fritidsaktiviteter inte är prioriterat enligt vårdriktlinjer och att det även fanns andra hindrande faktorer som begränsar arbetsterapeuterna att arbeta med fritidsaktiviteter. Det framgick även att det fanns stöttande faktorer som gör det möjligt för arbetsterapeuterna att hitta lösningar på hur de kan arbeta med fritidsaktiviteter och att de upplever att det har positiv påverkan på klienterna som väger över de annars negativa konsekvenser som kan uppstå vid brist av en meningsfull fritid. Resultatet visar att arbetsterapeuterna inkluderar fritidsaktiviteter vid kartläggningen, ger tips och råd kring fritidsaktiviteter samt har möjlighet att sätta in interventioner som kan gynna både vardagliga aktiviteter och fritidsaktiviteter. Arbetsterapeuterna upplever att klientens efterfrågan av hjälp varierar beroende på vilken diagnos klienten har. Slutsats: Arbetsterapeuterna som arbetade med fritidsaktiviteter upplevde att det hade en positiv effekt för barn- och ungdomar med funktionsnedsättning. Fritidsaktiviteter är ett område som bör inkluderas mer i arbetsterapin eftersom det främjar självständighet och delaktighet i vården men även i klienternas liv. Arbetsterapeuter besitter den kunskap som behövs för att arbeta och anpassa fritidsaktiviteter i olika miljöer och behov. / Purpose: The aim of this study was to examine occupational therapists' experience of working with leisure activities for children and adolescents who live with functional impairments in pediatric facilities in Sweden. Method: The study was conducted with a qualitative data collection method with semi-instructed interviews through phone or skype with seven occupational therapists with experience and that are working in a pediatric facility with children and adolescents who live with functional impairments. In the analysis of the interviews a qualitative content analysis was used. Result: The results showed that leisure activities are not a prioritization according to health guidelines and that there are also other factors that prevent occupational therapists from working with leisure activities. It also appears that there are supporting factors that enable occupational therapists to find solutions of how they can work with leisure activities and that their experience is that leisure activities have a positive impact on clients weighing over the otherwise negative consequences that can arise from lack of meaningful leisure. The result showed that occupational therapists include leisure activities in information gathering, provide tips and advice and have the opportunity to use intervention that benefit both activities of daily living and leisure activities. The occupational therapists find that the clients demand for help vary depending on the diagnosis the client has. Conclusion: The Occupational therapists that are working with leisure activities experience that they have a positive effect on children and adolescents with functional impairments. And that is a topic that should be included more in occupational therapy because it promotes independence and participation in care but also in the client’s life. Occupational therapists possess the knowledge needed to be able to work and adapt leisure activities in different environments and needs.

Enabling multiple base stations to utilize the spatial dimension in a coordinated manner has been shown to be a fruitful technique for improving the spectral efficiency in wireless interference networks. This thesis considers multicell systems where base stations and mobile stations are equipped with multiple antennas. The base stations coordinate their spatial precoding, but individually serve their mobile stations with data. For such coordinated precoding systems, interference alignment (IA) is a useful theoretical tool, due to its ability to serve the maximum number of interference-free data streams. Three topics related to interference alignment and coordinated precoding are studied. First, the feasibility of IA over a joint space-frequency signal space is studied. A necessary condition for space-frequency IA feasibility is derived, and the possible gain over space-only IA is analyzed. An upper bound on the degree of freedom gain is shown to increase in the number of subcarriers, but decrease in the number of antennas. Numerical studies, using synthetically generated channels and real-world channels obtained from indoors and outdoors channel measurements, are used for sum rate performance evaluation. The results show that although a degree of freedom gain is noticeable due to the space-frequency precoding, the sum rate of the system is mainly improved due to a power gain. Second, distributed channel state information (CSI) acquisition techniques are proposed, which provide estimates of the information necessary to perform distributed coordinated precoding. The methods are based on pilot-assisted channel estimation in the uplink and downlink, and correspond to different tradeoffs between feedback and signaling, backhaul use, and computational complexity. Naively applying the existing WMMSE algorithm for distributed coordinated precoding together with the estimated CSI however results in poor performance. A robustification of the algorithm is therefore proposed, relying on the well known diagonal loading technique. An inherent property of the WMMSE solutions is derived and, when enforced onto solutions with imperfect CSI, results in diagonally loaded receive filters. Numerical simulations show the effectiveness of the proposed robustification. Further, the proposed robustified and distributed WMMSE algorithm performs well compared to existing state-of-the-art robust WMMSE algorithms. In contrast to our approach, the existing methods however rely on centralized CSI acquisition. Third, coordinated precoding systems with hardware impairments are studied. Assuming that impairment compensation techniques have been applied, a model is used to describe the aggregate effect of the residual hardware impairments. An iterative resource allocation method accounting for the residual hardware impairments is derived, based on an existing resource allocation framework. Numerical simulations show that the proposed method outperforms all benchmarks. In particular, the gain over impairments-aware time-division multiple access is substantial. / Genom att låta flera radiobasstationer samarbeta är det möjligt att förbättra spektraleffektiviteten i trådlösa interferensnätverk. Fokus i denna licentiatavhandling ligger på multicellnätverk där både radiobasstationer och mobilenheter har flera antenner. Radiobasstationerna väljer sina spatiella förkodare gemensamt, men skickar data individuellt till sina respektive mobilenheter. För sådana system med koordinerad förkodning ('coordinated precoding') är interferensupprätning ('interference alignment') ett användbart teoretiskt verktyg, eftersom det möjliggör överföring av maximalt antal dataströmmar i nätverket. I avhandlingen studeras tre aspekter av interferensupprätning och koordinerad förkodning. Först undersöks interferensupprätning när signalrummet består av en kombination av rymd- och frekvensdimensioner. Ett nödvändigt villkor härleds för existensen av rymd/frekvens-interferensupprätning, och prestandavinsten analyseras i jämförelse med system där enbart rymddimensionerna används för interferensupprätning. Det föreslagna systemet utvärderas med hjälp av numeriska simuleringar och uppmätta inomhus- och utomhuskanaler. Resultaten visar att rymd/frekvens-interferensupprätning ger upphov till ett ökat antal frihetsgrader, men att summadatatakten främst förbättras tack vare en upplevd effektförstärkning. Därefter undersöks tekniker för skattning av den nödvändiga kanalkännedom som krävs för att genomföra koordinerad förkodning. Det finns flera sätt att erhålla den nödvändiga informationen, t.ex. genom olika kombinationer av kanalskattning, feedback, signalering och användning av backhaulnätverk. Speciellt söks distribuerade metoder, eftersom dessa är fördelaktiga vid praktisk implementering. Tre metoder för skattning av kanalkännedom föreslås. Dessa motsvarar olika avvägningar mellan kanalskattning och signalering, och en av metoderna är helt distribuerad. När den skattade informationen används med en existerande algoritm för koordinerad förkodning blir prestandan undermålig. Därför föreslås två förändringar av algoritmen, vilka leder till mer robusta prestanda. Förändringarna bygger på den välkända diagonal loading-tekniken. Utvärdering av det föreslagna systemet, som består av distribuerad erhållning av kanalkännedom samt den förbättrade algoritmen för koordinerad förkodning, genomförs med numerisk simulering. Resulterande prestanda är i nivå med ett tidigare föreslaget system, som dock kräver centraliserad tillgång till kanalskattningarna, till skillnad från vår nya lösning. Slutligen studeras ett system med koordinerad förkodning och icke-perfekt radiohårdvara. En modell för distortionsbruset orsakad av bristerna i radiohårdvaran används, och en iterativ resurstilldelningsteknik föreslås baserad på ett existerande ramverk. Den föreslagna algoritmen kan implementeras distribuerat över mobilenheterna, men kan i allmänhet inte implementeras distribuerat över radiobasstationerna. Den föreslagna algoritmen utvärderas med numeriska simuleringar, och resultaten visar att prestanda är bättre än alla referensmetoder. Detta visar betydelsen av att hantera bristerna i radiohårdvaran i resurstilldelningen. Sammantaget visar avhandlingen på möjligheterna att öka spektraleffektiviteten i framtida multicellnätverk med hjälp av koordinerad förkodning. / <p>QC 20140512</p>

The purpose of this study was to examine the value relevance of goodwill impairments in regard to market value. A quantitative methodological approach was used to determine if the relation between goodwill impairments was influenced by different institutional settings, which was the first research question. The second research question was to see if there was a learning effect associated with the use of goodwill impairments that has appeared in the post- implementation period of the mandatory IFRS standards, that were enforced in the European Union in 2005. This was done by statistically comparing data from Swedish firms with data from British firms. The findings show that there are indeed institutional differences, but the evidence also suggests a learning effect to some extent. These findings add to the literature that there are important institutional differences and learning effects associated with the implementation of accounting standards, as well as offering some insight to standard setters on the value relevance of goodwill impairments.

Education reform in schools has focused on inclusion of all students in general education environments and accountability measures. Students with cognitive impairments are mandated to participate in standards-based alternate assessments. Special education teachers in a school district in a southeastern state in this study have been faced with the challenge of implementing these assessments. A bounded case study design was used to examine their perceptions of the use of standards-based alternate assessments for students with cognitive impairments. Guiding research questions focused on the nature and process of implementing alternate assessments. Resistance to change was the conceptual framework. The bounded case included 3 elementary, 1 middle school, and 4 high school special education teachers who have taught students with mild to moderate cognitive disabilities in self-contained classrooms in the district. Teachers were interviewed and data were coded and analyzed for common themes. Results included implementation concerns such as time for administration, scoring issues, lack of usefulness of assessment results, inappropriate expectations for performance, and lack of validity of assessments for cognitively impaired students. Recommendations included decision makers' reconsideration of the procedures for implementation and establishing validity and usefulness of standards-based alternate assessments. Findings in this study reflected teachers' resistance to change, but were informative in providing local decision makers with an opportunity for social change that includes examination of where current policy fails to accommodate students with cognitive impairments and creation of appropriate policy and assessments that actually benefit those students.

No description available.