User Experience in Human-Technology Interaction. Communication, context and evaluation methodology

En esta Tesis se presentan dos líneas de investigación relacionadas y que contribuyen a las áreas de Interacción Hombre-Tecnología (o Máquina; siglas en inglés: HTI o HMI), lingüística computacional y evaluación de la experiencia del usuario. Las dos líneas en cuestión son el diseño y la evaluación centrada en el usuario de sistemas de Interacción Hombre-Máquina avanzados. En la primera parte de la Tesis (Capítulos 2 a 4) se abordan cuestiones fundamentales del diseño de sistemas HMI avanzados. El Capítulo 2 presenta una panorámica del estado del arte de la investigación en el ámbito de los sistemas conversacionales multimodales, con la que se enmarca el trabajo de investigación presentado en el resto de la Tesis. Los Capítulos 3 y 4 se centran en dos grandes aspectos del diseño de sistemas HMI: un gestor del diálogo generalizado para tratar la Interacción Hombre-Máquina multimodal y sensible al contexto, y el uso de agentes animados personificados (ECAs) para mejorar la robustez del diálogo, respectivamente. El Capítulo 3, sobre gestión del diálogo, aborda el tratamiento de la heterogeneidad de la información proveniente de las modalidades comunicativas y de los sensores externos. En este capítulo se propone, en un nivel de abstracción alto, una arquitectura para la gestión del diálogo con influjos heterogéneos de información, apoyándose en el uso de State Chart XML. En el Capítulo 4 se presenta una contribución a la representación interna de intenciones comunicativas, y su traducción a secuencias de gestos a ejecutar por parte de un ECA, diseñados específicamente para mejorar la robustez en situaciones de diálogo críticas que pueden surgir, por ejemplo, cuando se producen errores de entendimiento en la comunicación entre el usuario humano y la máquina. Se propone, en estas páginas, una extensión del Functional Mark-up Language definido en el marco conceptual SAIBA. Esta extensión permite representar actos comunicativos que realizan intenciones del emisor (la máquina) que no se pretende sean captadas conscientemente por el receptor (el usuario humano), pero con las que se pretende influirle a éste e influir el curso del diálogo. Esto se consigue mediante un objeto llamado Base de Intenciones Comunicativas (en inglés, Communication Intention Base, o CIB). La representación en el CIB de intenciones “no claradas” además de las explícitas permite la construcción de actos comunicativos que realizan simultáneamente varias intenciones comunicativas. En el Capítulo 4 también se describe un sistema experimental para el control remoto (simulado) de un asistente domótico, con autenticación de locutor para dar acceso, y con un ECA en el interfaz de cada una de estas tareas. Se incluye una descripción de las secuencias de comportamiento verbal y no verbal de los ECAs, que fueron diseñados específicamente para determinadas situaciones con objeto de mejorar la robustez del diálogo. Los Capítulos 5 a 7 conforman la parte de la Tesis dedicada a la evaluación. El Capítulo 5 repasa antecedentes relevantes en la literatura de tecnologías de la información en general, y de sistemas de interacción hablada en particular. Los principales antecedentes en el ámbito de la evaluación de la interacción sobre los cuales se ha desarrollado el trabajo presentado en esta Tesis son el Technology Acceptance Model (TAM), la herramienta Subjective Assessment of Speech System Interfaces (SASSI), y la Recomendación P.851 de la ITU-T. En el Capítulo 6 se describen un marco y una metodología de evaluación aplicados a la experiencia del usuario con sistemas HMI multimodales. Se desarrolló con este propósito un novedoso marco de evaluación subjetiva de la calidad de la experiencia del usuario y su relación con la aceptación por parte del mismo de la tecnología HMI (el nombre dado en inglés a este marco es Subjective Quality Evaluation Framework). En este marco se articula una estructura de clases de factores subjetivos relacionados con la satisfacción y aceptación por parte del usuario de la tecnología HMI propuesta. Esta estructura, tal y como se propone en la presente tesis, tiene dos dimensiones ortogonales. Primero se identifican tres grandes clases de parámetros relacionados con la aceptación por parte del usuario: “agradabilidad ” (likeability: aquellos que tienen que ver con la experiencia de uso, sin entrar en valoraciones de utilidad), rechazo (los cuales sólo pueden tener una valencia negativa) y percepción de utilidad. En segundo lugar, este conjunto clases se reproduce para distintos “niveles, o focos, percepción del usuario”. Éstos incluyen, como mínimo, un nivel de valoración global del sistema, niveles correspondientes a las tareas a realizar y objetivos a alcanzar, y un nivel de interfaz (en los casos propuestos en esta tesis, el interfaz es un sistema de diálogo con o sin un ECA). En el Capítulo 7 se presenta una evaluación empírica del sistema descrito en el Capítulo 4. El estudio se apoya en los mencionados antecedentes en la literatura, ampliados con parámetros para el estudio específico de los agentes animados (los ECAs), la auto-evaluación de las emociones de los usuarios, así como determinados factores de rechazo (concretamente, la preocupación por la privacidad y la seguridad). También se evalúa el marco de evaluación subjetiva de la calidad propuesto en el capítulo anterior. Los análisis de factores efectuados revelan una estructura de parámetros muy cercana conceptualmente a la división de clases en utilidad-agradabilidad-rechazo propuesta en dicho marco, resultado que da cierta validez empírica al marco. Análisis basados en regresiones lineales revelan estructuras de dependencias e interrelación entre los parámetros subjetivos y objetivos considerados. El efecto central de mediación, descrito en el Technology Acceptance Model, de la utilidad percibida sobre la relación de dependencia entre la intención de uso y la facilidad de uso percibida, se confirma en el estudio presentado en la presente Tesis. Además, se ha encontrado que esta estructura de relaciones se fortalece, en el estudio concreto presentado en estas páginas, si las variables consideradas se generalizan para cubrir más ampliamente las categorías de agradabilidad y utilidad contempladas en el marco de evaluación subjetiva de calidad. Se ha observado, asimismo, que los factores de rechazo aparecen como un componente propio en los análisis de factores, y además se distinguen por su comportamiento: moderan la relación entre la intención de uso (que es el principal indicador de la aceptación del usuario) y su predictor más fuerte, la utilidad percibida. Se presentan también resultados de menor importancia referentes a los efectos de los ECAs sobre los interfaces de los sistemas de diálogo y sobre los parámetros de percepción y las valoraciones de los usuarios que juegan un papel en conformar su aceptación de la tecnología. A pesar de que se observa un rendimiento de la interacción dialogada ligeramente mejor con ECAs, las opiniones subjetivas son muy similares entre los dos grupos experimentales (uno interactuando con un sistema de diálogo con ECA, y el otro sin ECA). Entre las pequeñas diferencias encontradas entre los dos grupos destacan las siguientes: en el grupo experimental sin ECA (es decir, con interfaz sólo de voz) se observó un efecto más directo de los problemas de diálogo (por ejemplo, errores de reconocimiento) sobre la percepción de robustez, mientras que el grupo con ECA tuvo una respuesta emocional más positiva cuando se producían problemas. Los ECAs parecen generar inicialmente expectativas más elevadas en cuanto a las capacidades del sistema, y los usuarios de este grupo se declaran más seguros de sí mismos en su interacción. Por último, se observan algunos indicios de efectos sociales de los ECAs: la “amigabilidad ” percibida los ECAs estaba correlada con un incremento la preocupación por la seguridad. Asimismo, los usuarios del sistema con ECAs tendían más a culparse a sí mismos, en lugar de culpar al sistema, de los problemas de diálogo que pudieran surgir, mientras que se observó una ligera tendencia opuesta en el caso de los usuarios del sistema con interacción sólo de voz. ABSTRACT This Thesis presents two related lines of research work contributing to the general fields of Human-Technology (or Machine) Interaction (HTI, or HMI), computational linguistics, and user experience evaluation. These two lines are the design and user-focused evaluation of advanced Human-Machine (or Technology) Interaction systems. The first part of the Thesis (Chapters 2 to 4) is centred on advanced HMI system design. Chapter 2 provides a background overview of the state of research in multimodal conversational systems. This sets the stage for the research work presented in the rest of the Thesis. Chapers 3 and 4 focus on two major aspects of HMI design in detail: a generalised dialogue manager for context-aware multimodal HMI, and embodied conversational agents (ECAs, or animated agents) to improve dialogue robustness, respectively. Chapter 3, on dialogue management, deals with how to handle information heterogeneity, both from the communication modalities or from external sensors. A highly abstracted architectural contribution based on State Chart XML is proposed. Chapter 4 presents a contribution for the internal representation of communication intentions and their translation into gestural sequences for an ECA, especially designed to improve robustness in critical dialogue situations such as when miscommunication occurs. We propose an extension of the functionality of Functional Mark-up Language, as envisaged in much of the work in the SAIBA framework. Our extension allows the representation of communication acts that carry intentions that are not for the interlocutor to know of, but which are made to influence him or her as well as the flow of the dialogue itself. This is achieved through a design element we have called the Communication Intention Base. Such r pr s ntation of “non- clar ” int ntions allows th construction of communication acts that carry several communication intentions simultaneously. Also in Chapter 4, an experimental system is described which allows (simulated) remote control to a home automation assistant, with biometric (speaker) authentication to grant access, featuring embodied conversation agents for each of the tasks. The discussion includes a description of the behavioural sequences for the ECAs, which were designed for specific dialogue situations with particular attention given to the objective of improving dialogue robustness. Chapters 5 to 7 form the evaluation part of the Thesis. Chapter 5 reviews evaluation approaches in the literature for information technologies, as well as in particular for speech-based interaction systems, that are useful precedents to the contributions of the present Thesis. The main evaluation precedents on which the work in this Thesis has built are the Technology Acceptance Model (TAM), the Subjective Assessment of Speech System Interfaces (SASSI) tool, and ITU-T Recommendation P.851. Chapter 6 presents the author’s work in establishing an valuation framework and methodology applied to the users’ experience with multimodal HMI systems. A novel user-acceptance Subjective Quality Evaluation Framework was developed by the author specifically for this purpose. A class structure arises from two orthogonal sets of dimensions. First we identify three broad classes of parameters related with user acceptance: likeability factors (those that have to do with the experience of using the system), rejection factors (which can only have a negative valence) and perception of usefulness. Secondly, the class structure is further broken down into several “user perception levels”; at the very least: an overall system-assessment level, task and goal-related levels, and an interface level (e.g., a dialogue system with or without an ECA). An empirical evaluation of the system described in Chapter 4 is presented in Chapter 7. The study was based on the abovementioned precedents in the literature, expanded with categories covering the inclusion of an ECA, the users’ s lf-assessed emotions, and particular rejection factors (privacy and security concerns). The Subjective Quality Evaluation Framework proposed in the previous chapter was also scrutinised. Factor analyses revealed an item structure very much related conceptually to the usefulness-likeability-rejection class division introduced above, thus giving it some empirical weight. Regression-based analysis revealed structures of dependencies, paths of interrelations, between the subjective and objective parameters considered. The central mediation effect, in the Technology Acceptance Model, of perceived usefulness on the dependency relationship of intention-to-use with perceived ease of use was confirmed in this study. Furthermore, the pattern of relationships was stronger for variables covering more broadly the likeability and usefulness categories in the Subjective Quality Evaluation Framework. Rejection factors were found to have a distinct presence as components in factor analyses, as well as distinct behaviour: they were found to moderate the relationship between intention-to-use (the main measure of user acceptance) and its strongest predictor, perceived usefulness. Insights of secondary importance are also given regarding the effect of ECAs on the interface of spoken dialogue systems and the dimensions of user perception and judgement attitude that may have a role in determining user acceptance of the technology. Despite observing slightly better performance values in the case of the system with the ECA, subjective opinions regarding both systems were, overall, very similar. Minor differences between two experimental groups (one interacting with an ECA, the other only through speech) include a more direct effect of dialogue problems (e.g., non-understandings) on perceived dialogue robustness for the voice-only interface test group, and a more positive emotional response for the ECA test group. Our findings further suggest that the ECA generates higher initial expectations, and users seem slightly more confident in their interaction with the ECA than do those without it. Finally, mild evidence of social effects of ECAs was also found: the perceived friendliness of the ECA increased security concerns, and ECA users may tend to blame themselves rather than the system when dialogue problems are encountered, while the opposite may be true for voice-only users.

Análisis, modelado e igualación no lineal de arrays paramétricos acústicos

La presente Tesis analiza y desarrolla metodología específica que permite la caracterización de sistemas de transmisión acústicos basados en el fenómeno del array paramétrico. Este tipo de estructuras es considerado como uno de los sistemas más representativos de la acústica no lineal con amplias posibilidades tecnológicas. Los arrays paramétricos aprovechan la no linealidad del medio aéreo para obtener en recepción señales en el margen sónico a partir de señales ultrasónicas en emisión. Por desgracia, este procedimiento implica que la señal transmitida y la recibida guardan una relación compleja, que incluye una fuerte ecualización así como una distorsión apreciable por el oyente. Este hecho reduce claramente la posibilidad de obtener sistemas acústicos de gran fidelidad. Hasta ahora, los esfuerzos tecnológicos dirigidos al diseño de sistemas comerciales han tratado de paliar esta falta de fidelidad mediante técnicas de preprocesado fuertemente dependientes de los modelos físicos teóricos. Estos están basados en la ecuación de propagación de onda no lineal. En esta Tesis se propone un nuevo enfoque: la obtención de una representación completa del sistema mediante series de Volterra que permita inferir un sistema de compensación computacionalmente ligero y fiable. La dificultad que entraña la correcta extracción de esta representación obliga a desarrollar una metodología completa de identificación adaptada a este tipo de estructuras. Así, a la hora de aplicar métodos de identificación se hace indispensable la determinación de ciertas características iniciales que favorezcan la parametrización del sistema. En esta Tesis se propone una metodología propia que extrae estas condiciones iniciales. Con estos datos, nos encontramos en disposición de plantear un sistema completo de identificación no lineal basado en señales pseudoaleatorias, que aumenta la fiabilidad de la descripción del sistema, posibilitando tanto la inferencia de la estructura basada en bloques subyacente, como el diseño de mecanismos de compensación adecuados. A su vez, en este escenario concreto en el que intervienen procesos de modulación, factores como el punto de trabajo o las características físicas del transductor, hacen inviables los algoritmos de caracterización habituales. Incluyendo el método de identificación propuesto. Con el fin de eliminar esta problemática se propone una serie de nuevos algoritmos de corrección que permiten la aplicación de la caracterización. Las capacidades de estos nuevos algoritmos se pondrán a prueba sobre un prototipo físico, diseñado a tal efecto. Para ello, se propondrán la metodología y los mecanismos de instrumentación necesarios para llevar a cabo el diseño, la identificación del sistema y su posible corrección, todo ello mediante técnicas de procesado digital previas al sistema de transducción. Los algoritmos se evaluarán en términos de error de modelado a partir de la señal de salida del sistema real frente a la salida sintetizada a partir del modelo estimado. Esta estrategia asegura la posibilidad de aplicar técnicas de compensación ya que éstas son sensibles a errores de estima en módulo y fase. La calidad del sistema final se evaluará en términos de fase, coloración y distorsión no lineal mediante un test propuesto a lo largo de este discurso, como paso previo a una futura evaluación subjetiva. ABSTRACT This Thesis presents a specific methodology for the characterization of acoustic transmission systems based on the parametric array phenomenon. These structures are well-known representatives of the nonlinear acoustics field and display large technological opportunities. Parametric arrays exploit the nonlinear behavior of air to obtain sonic signals at the receptors’side, which were generated within the ultrasonic range. The underlying physical process redunds in a complex relationship between the transmitted and received signals. This includes both a strong equalization and an appreciable distortion for a human listener. High fidelity, acoustic equipment based on this phenomenon is therefore difficult to design. Until recently, efforts devoted to this enterprise have focused in fidelity enhancement based on physically-informed, pre-processing schemes. These derive directly from the nonlinear form of the wave equation. However, online limited enhancement has been achieved. In this Thesis we propose a novel approach: the evaluation of a complete representation of the system through its projection onto the Volterra series, which allows the posterior inference of a computationally light and reliable compensation scheme. The main difficulty in the derivation of such representation strives from the need of a complete identification methodology, suitable for this particular type of structures. As an example, whenever identification techniques are involved, we require preliminary estimates on certain parameters that contribute to the correct parameterization of the system. In this Thesis we propose a methodology to derive such initial values from simple measures. Once these information is made available, a complete identification scheme is required for nonlinear systems based on pseudorandom signals. These contribute to the robustness and fidelity of the resulting model, and facilitate both the inference of the underlying structure, which we subdivide into a simple block-oriented construction, and the design of the corresponding compensation structure. In a scenario such as this where frequency modulations occur, one must control exogenous factors such as devices’ operation point and the physical properties of the transducer. These may conflict with the principia behind the standard identification procedures, as it is the case. With this idea in mind, the Thesis includes a series of novel correction algorithms that facilitate the application of the characterization results onto the system compensation. The proposed algorithms are tested on a prototype that was designed and built for this purpose. The methodology and instrumentation required for its design, the identification of the overall acoustic system and its correction are all based on signal processing techniques, focusing on the system front-end, i.e. prior to transduction. Results are evaluated in terms of input-output modelling error, considering a synthetic construction of the system. This criterion ensures that compensation techniques may actually be introduced, since these are highly sensible to estimation errors both on the envelope and the phase of the signals involved. Finally, the quality of the overall system will be evaluated in terms of phase, spectral color and nonlinear distortion; by means of a test protocol specifically devised for this Thesis, as a prior step for a future, subjective quality evaluation.

Medida del consumo de energía en la descodificación de vídeos

Este proyecto se encuentra adscrito a la línea de investigación de optimización de consumo en terminales multimedia móviles que el Grupo de Diseño Electrónico y Microelectrónico (GDEM) de la UPM (Universidad Politécnica de Madrid) está llevando a cabo. Los sistemas empotrados móviles (Smartphone, Tablet,...) están alimentados con baterías. En este tipo de sistemas, una de las aplicaciones que más rápidamente consume energía es la descodificación de secuencias de vídeo. En este trabajo, queremos medir el consumo de energía de distintos descodificadores de vídeo para distintas secuencias, con el objetivo de entender mejor cómo se consume esta energía y poder encontrar diferentes métodos que lo reduzcan. Para ello comenzaremos describiendo nuestro entorno de trabajo, tanto el hardware como el software utilizado. Respeto al hardware cabe destacar el uso de una PandaBoard y un Smart Power de Odroid, entre otros muchos elementos utilizados, los cuales serán debidamente explicados en las siguientes páginas de este proyecto. Mientras que para el software destaca el uso de dos tipos de descodificadores uno CBP y otro PHP, los cuales serán descritos en profundidad en los siguientes capítulos de este documento. Este entorno de trabajo nos servirá para el estudio de las diferentes secuencias de vídeo, cuya codificación ha sido llevada en paralelo con otro proyecto que se está realizando en el grupo de GDEM de la UPM, y cuyo objetivo es el estudio de la calidad subjetiva durante la descodificación del mismo conjunto de secuencias de vídeo. Todas estas secuencias de vídeo han sido codificadas con diferentes parámetros de calidad y diversas estructuras de imágenes, para obtener así un banco de pruebas lo más amplio posible. Gracias a la obtención de estas secuencias de vídeo y utilizando nuestro entorno de trabajo, pasaremos a estudiar el consumo de energía que se produce al descodificar una a una todas las posibles secuencias de vídeo, dependiendo todo esto de su estructura de imágenes, su calidad y por supuesto, el descodificador utilizado en cada caso. Para terminar, se mostrará una comparativa entre los diferentes resultados obtenidos y se hará una discusión de estos, obteniendo en este caso, un resumen de los datos más significativos, así como las conclusiones más importantes obtenidas durante todo este trabajo. Al término de este proyecto y en unión con el estudio que se está llevando a cabo en paralelo sobre la calidad subjetiva, queda como línea futura de investigación encontrar el compromiso entre el consumo de energía de diferentes secuencias de vídeo y la calidad subjetiva de dichas secuencias. ABSTRACT. This project is assigned to the research line on consumption optimization in mobile multimedia terminals carried out by the Group of Electronic Design and Microelectronics (GDEM) of the Polytechnic University of Madrid (UPM). Embedded mobile systems (smartphones, tablets...) are powered by batteries. In such systems, one of the applications that more rapidly consumes power is the decoding of video streams. In this work, we measure the power consumption of different video decoders for different streams, in order to better understand how this energy is consumed and to find different methods to reduce it. To this end, we start by describing our working environment, both hardware and software used. As for the hardware, it is worth mentioning the use of PandaBoard and Smart Power Odroid, among many other elements, which will be duly explained in the following pages of this project. As for the software, we highlight the use of two types of decoders, CBP and PHP, which will be described in detail in the following chapters of this document. This working environment will help us to study different video streams, whose coding has been perfor-med in parallel under another project that is being carried out in the GDEM group of the UPM, and whose objective is the study of subjective quality for decoding the same set of video streams. All these video streams have been encoded with different quality parameters and image structures in order to obtain the widest set of samples. Thanks to the production of these video streams and the use of our working environment, we study the power consumption that occurs when decoding one by one all possible video streams, depending on the image structure, their quality and, of course, the decoder used in each case. Finally, we show a comparison between the different results and a discussion of these, obtaining a sum-mary of the most significant data and the main conclusions obtained during this project. Upon completion of this project and in conjunction with the project on the study of subjective quality that is being carried out in parallel, a future line of research could consist in finding the compromise between power consumption of different video streams and the subjective quality of these.

Perceptual differences of marketing journals:a worldwide perspective

The practice of evaluating faculty and business schools based on their journal publications has increased the emphasis on research output in peer reviewed journals. Since journal standings are a frequently debated issue, this study seeks to examine the perceptual differences of journals between different segments of marketing academics. Based on a worldwide online survey, journals are assessed in terms of four subjective quality metrics: journal familiarity, average rank position, percent of respondents who classify a journal as top tier, and readership. It is demonstrated that an individual's geographic origin, research interests or journal affiliation can have a significant impact on journal rankings.

How do statisticians perceive statistics journals?

Since researchers and academic institutions are increasingly evaluated based on their publication record in peer reviewed journals, it is crucial to assess how the statistics community perceives statistics journals. This study presents four subjective quality metrics of statistics journals as expressed by different segments of statisticians. Based on a worldwide sample of 2,190 statisticians, our findings indicate that the research interest and geographic origin of the researcher have a significant impact on journal perceptions, which are highly correlated with a journal's total number of citations.

Presbyopic LASIK using hybrid bi-aspheric micro-monovision ablation profile for presbyopic corneal treatments

Purpose: To evaluate distance and near image quality after hybrid bi-aspheric multifocal central presbyLASIK treatments. Design: Consecutive case series. Methods: Sixty-four eyes of 32 patients consecutively treated with central presbyLASIK were assessed. The mean age of the patients was 51 ± 3 years with a mean spherical equivalent refraction of-1.08 ± 2.62 diopters (D) and mean astigmatism of 0.52 ± 0.42 D. Monocular corrected distance visual acuity (CDVA), corrected near visual acuity (CNVA), and distance corrected near visual acuity (DCNVA) of nondominant eyes; binocular uncorrected distance visual acuity (UDVA); uncorrected intermediate visual acuity (UIVA); distance corrected intermediate visual acuity (DCIVA); and uncorrected near visual acuity (UNVA) were assessed pre- and postoperatively. Subjective quality of vision and near vision was assessed using the 10-item Rasch-scaled Quality of Vision and Near Activity Visual Questionnaire, respectively. Results: At 1 year postoperatively, 93% of patients achieved 20/20 or better binocular UDVA; 90% and 97% of patients had J2 or better UNVA and UIVA, respectively; 7% lost 2 Snellen lines of CDVA; Strehl ratio reduced by ~-4% ± 14%. Defocus curves revealed a loss of half a Snellen line at best focus, with no change for intermediate vergence (-1.25 D) and a mean gain of 2 lines for near vergence (-3 D). Conclusions: Presbyopic treatment using a hybrid bi-aspheric micro-monovision ablation profile is safe and efficacious. The postoperative outcomes indicate improvements in binocular vision at far, intermediate, and near distances with improved contrast sensitivity. A 19% retreatment rate should be considered to increase satisfaction levels, besides a 3% reversal rate.

Randomized crossover trial of silicone hydrogel presbyopic contact lenses

PURPOSE: To assess the performance of four commercially available silicone hydrogel multifocal monthly contact lens designs against monovision. METHODS: A double-masked randomized crossover trial of Air Optix Aqua multifocal, PureVision 2 for Presbyopia, Acuvue OASYS for Presbyopia, Biofinity multifocal, and monovision with Biofinity contact lenses was conducted on 35 presbyopes (54.3 ± 6.2 years). After 4 weeks of wear, visual performance was quantified by high- and low-contrast visual acuity under photopic and mesopic conditions, reading speed, defocus curves, stereopsis, halometry, aberrometry, Near Activity Visual Questionnaire rating, and subjective quality of vision scoring. Bulbar, limbal, and palpebral hyperemia and corneal staining were graded to monitor the impact of each contact lens on ocular physiology. RESULTS: High-contrast photopic visual acuity (p = 0.102), reading speed (F = 1.082, p = 0.368), and aberrometry (F = 0.855, p = 0.493) were not significantly different between presbyopic lens options. Defocus curve profiles (p <0.001), stereopsis (p <0.001), halometry (F = 4.101, p = 0.004), Near Activity Visual Questionnaire (F = 3.730, p = 0.007), quality of vision (p = 0.002), bulbar hyperemia (p = 0.020), and palpebral hyperemia (p = 0.012) differed significantly between lens types, with the Biofinity multifocal lens design principal (center-distance lens was fitted to the dominant eye and a center-near lens to the nondominant eye) typically outperforming the other lenses. CONCLUSIONS: Although ocular aberration variation between individuals largely masks the differences in optics between current multifocal contact lens designs, certain design strategies can outperform monovision, even in early presbyopes.

Investigating the utility of clinical assessments to predict success with presbyopic contact lens correction

PURPOSE: To determine the utility of a range of clinical and non-clinical indicators to aid the initial selection of the optimum presbyopic contact lens. In addition, to assess whether lens preference was influenced by the visual performance compared to the other designs trialled (intra-subject) or compared to participants who preferred other designs (inter-subject). METHODS: A double-masked randomised crossover trial of Air Optix Aqua multifocal, PureVision 2 for Presbyopia, Acuvue OASYS for Presbyopia, Biofinity multifocal and monovision was conducted on 35 presbyopes (54.3±6.2years). Participant lifestyle, personality, pupil characteristics and aberrometry were assessed prior to lens fitting. After 4 weeks of wear, high and low contrast visual acuity (VA) under photopic and mesopic conditions, reading speed, Near Activity Visual Questionnaire (NAVQ) rating, subjective quality-of-vision scoring, defocus curves, stereopsis, halometry, aberrometry and ocular physiology were quantified. RESULTS: After trialling all the lenses, preference was mixed (n=12 Biofinity, n=10 monovision, n=7 Purevision, n=4 Air Optix Aqua, n=2 Oasys). Lens preference was not dependent on personality (F=1.182, p=0.323) or the hours spent working at near (p=0.535) or intermediate (p=0.759) distances. No intersubject or strong intrasubject relationships emerged between lens preference and reading speed, NAVQ rating, halo size, aberrometry or ocular physiology (p>0.05). CONCLUSIONS: Participant lifestyle and personality, ocular optics, contact lens visual performance and ocular physiology provided poor indicators of the preferred lens type after 4 weeks of wear. This is confounded by the wide range of task visual demands of presbyopes and the limited optical differences between current multifocal contact lens designs.

Asymmetric 3D video coding based on regions of perceptual relevance

This dissertation presents a study and experimental research on asymmetric coding of stereoscopic video. A review on 3D technologies, video formats and coding is rst presented and then particular emphasis is given to asymmetric coding of 3D content and performance evaluation methods, based on subjective measures, of methods using asymmetric coding. The research objective was de ned to be an extension of the current concept of asymmetric coding for stereo video. To achieve this objective the rst step consists in de ning regions in the spatial dimension of auxiliary view with di erent perceptual relevance within the stereo pair, which are identi ed by a binary mask. Then these regions are encoded with better quality (lower quantisation) for the most relevant ones and worse quality (higher quantisation) for the those with lower perceptual relevance. The actual estimation of the relevance of a given region is based on a measure of disparity according to the absolute di erence between views. To allow encoding of a stereo sequence using this method, a reference H.264/MVC encoder (JM) has been modi ed to allow additional con guration parameters and inputs. The nal encoder is still standard compliant. In order to show the viability of the method subjective assessment tests were performed over a wide range of objective qualities of the auxiliary view. The results of these tests allow us to prove 3 main goals. First, it is shown that the proposed method can be more e cient than traditional asymmetric coding when encoding stereo video at higher qualities/rates. The method can also be used to extend the threshold at which uniform asymmetric coding methods start to have an impact on the subjective quality perceived by the observers. Finally the issue of eye dominance is addressed. Results from stereo still images displayed over a short period of time showed it has little or no impact on the proposed method.

Qualidade Subjetiva do Sono, Sintomas Depressivos e Sentimentos de Solidão em Idosos Institucionalizados e Não Institucionalizados

Parece existir uma associação entre solidão e uma pobre qualidade subjetiva do sono. Em reforço desta ideia, alguns estudos mostraram que os sentimentos de solidão se associam a uma menor satisfação do sono, mesmo que a sua duração não esteja diminuída. Outros mostraram que a solidão se associa a sintomas depressivos. Sabe-se que na institucionalização são frequentes os problemas de sono, depressão e solidão. No entanto, falta saber o que se passa nas respostas sociais portuguesas. Assim foram os nossos principais objetivos descrever a qualidade subjetiva do sono e analisar a intensidade dos sintomas depressivos e dos sintomas de solidão em idosos institucionalizados, comparar com uma subamostra de idosos não institucionalizados e analisar a relação entre estas variáveis nas duas subamostras. Cento e quarenta idosos, com 70 institucionalizados e 70 não institucionalizados foram emparelhados por idade, sexo, escolaridade, estado civil e sem défice cognitivo. A média de idades foi de 76,58 (DP = 6,10), sendo 104 mulheres e 36 homens. Como instrumentos para a análise utilizámos um Questionário Sociodemográfico, o Questionário sobre o Sono na Terceira Idade, o Inventário de Depressão Geriátrica e a Escala de Solidão da Universidade da Califórnia, Los Angeles. Verificou-se que os idosos institucionalizados apresentavam mais sentimentos de solidão do que os não institucionalizados. Contudo, não se verificaram diferenças entre as duas subamostras em relação aos sintomas depressivos e à qualidade subjetiva do sono. Através de uma análise correlacional verificou-se nas duas subamostras que quanto pior a qualidade subjetiva do sono mais sintomas depressivos se observavam e quanto mais sintomas depressivos, mais sentimentos de solidão. Concluímos que não houve diferenças na qualidade subjetiva do sono pelo tipo de resposta social ainda que haja mais sintomas depressivos e sintomas de solidão nos idosos institucionalizados. Não encontrámos também relação entre o sono e a solidão nos idosos institucionalizados. / There seems to be an association between loneliness and poor subjective sleep quality. In support of this idea, some studies have shown that feelings of loneliness are associated with less satisfaction sleep, even if your life is not diminished. Others have shown that loneliness is associated with depressive symptoms. It is known that in the institutionalization are frequent problems with sleeping, depression and loneliness. However, lack know what is happening in the Portuguese social responses. So were our main objectives describe the subjective quality of sleep and analyze the intensity of depressive symptoms and loneliness symptoms in institutionalized elderly, compared with a non-institutionalized elderly subsample and analyze the relationship between these variables in both subsamples. One hundred and forty older adults, with 70 institutionalized and 70 non-institutionalized were matched by age, sex, education, marital status and without cognitive impairment. The average age was 76.58 (SD = 6.10), including 104 women and 36 men. As tools for the analysis we used a sociodemographic questionnaire, the Questionnaire About Sleep in the Older Adults, Geriatric Depression Inventory and the Loneliness Scale of the University of California, Los Angeles. It was found that the institutionalized older adults had more feelings of loneliness than noninstitutionalized. However, there were no differences between the two subsamples in relation to depressive symptoms and subjective sleep quality. Through a correlational analysis it was found in the two subsamples that the worse the subjective sleep quality more depressive symptoms were observed and the more depressive symptoms, more feelings of loneliness. We concluded that there no differences in subjective sleep quality by the type of social response even though there are more depressive symptoms and symptoms of loneliness in the elderly. Also we did not find relationship between sleep and loneliness in the elderly.

Qualidade subjetiva do sono, sintomas depressivos, sentimentos de solidão e institucionalização em pessoas idosas

RESUMO Objetivos: A presente investigação teve como principais objetivos descrever a qualidade subjetiva do sono e as perturbações do sono e analisar a intensidade dos sintomas depressivos e dos sentimentos de solidão em idosos institucionalizados; comparar estes dados com um grupo de idosos não institucionalizados e analisar a relação entre estas variáveis nos dois grupos. Métodos: Este estudo insere-se no Projeto Trajetórias do Envelhecimento de Idosos em Resposta Social de onde foi retirada uma amostra de cento e quarenta idosos sem défice cognitivo, com 70 institucionalizados e 70 não institucionalizados emparelhados por idade, sexo, escolaridade e estado civil. A média de idades foi de 76,58 (DP = 6,10), incluindo 104 mulheres e 36 homens. Como instrumentos foram utilizados um Questionário Sociodemográfico, o Questionário sobre o Sono na Terceira Idade, a Escala Geriátrica de depressão e a Escala de Solidão da Universidade da Califórnia, Los Angeles. Resultados: Verificou-se que os idosos institucionalizados apresentavam mais sentimentos de solidão do que os não institucionalizados. Contudo, não se verificaram diferenças entre os dois grupos em relação aos sintomas depressivos, qualidade subjetiva do sono ou perturbações do sono, com algumas exceções: os idosos residentes na comunidade mostraram ter a perceção de demorar mais tempo a adormecer, de acordar mais cedo e de ter mais pesadelos. Através de uma análise correlacional verificou-se, na amostra global, que quanto pior a qualidade subjetiva do sono mais sintomas depressivos se observavam e quanto mais sintomas depressivos, mais sentimentos de solidão, não havendo, contudo, relação entre o sono e a solidão. Conclusões: Concluímos que a situação de institucionalização se acompanha de mais sentimentos de solidão, mas não de sintomas depressivos ou de pior qualidade de sono. Por esse motivo, sugere-se que se desenvolvam programas de intervenção dirigidos à solidão em idosos institucionalizados. ABSTRACT Aims: The main objectives of this investigation were to describe the subjective quality of sleep and sleep disorders and analyze the intensity of depressive and loneliness symptoms in institutionalized elderly people; compare these data against a non-institutionalized elderly people subsample and analyze the relationship between these variables in both subsamples. Method: This study is part of Trajectories of Elderly Aging in Social Response Project from which a sample of one hundred and forty elderly people with no cognitive impairment was taken, with 70 institutionalized and 70 non-institutionalized matched by age, sex, education, and marital status. The average age was 76.58 (SD = 6.10), including 104 women and 36 men. The tools used for this analysis were a sociodemographic questionnaire, the Questionnaire About Sleep in the Older Adults, Geriatric Depression Scale, and the Loneliness Scale of the University of California, Los Angeles. Results: The study confirmed that institutionalized elderly people had more feelings of loneliness than those non-institutionalized. However, there were no differences between the two subsamples regarding depressive symptoms and subjective sleep quality or sleep disturbances, with some exceptions: Elderly people living in the community showed to have the perception of taking more time to fall asleep, waking up earlier, and having more nightmares. Through a correlational analysis it was found, in both subsamples, that the worse the subjective sleep quality the more depressive symptoms were observed; and the more depressive symptoms, the more feelings of loneliness, despite of not existing a relation between sleep and loneliness. Conclusions: We concluded that institutionalization is linked to more feelings of loneliness but not to depressive symptoms nor to worse quality of sleep. For this reason, it is suggested that intervention programs are developed with a focus on elderly institutionalized populations.

Sleep and academic performance of Portuguese teenagers

Abstract: Sleep has numerous important functions in the body, such as consolidation of memory, concentration and learning. Changes in sleep cycles in adolescents lead to sleep deprivation with consequences to academic performance. Our research question was What are the sleep habits that influence school performance (study environment, study planning, study method, reading skills, motivation to study, overall school performance) in adolescents? We aimed to identify sleep habits predictors of the quality of school performance in adolescents. Research Methods: Crosssectional analytical study. Data were collected through a self-administered questionnaire with socio-demographic questions, sleep habits and school performance scale. The sample consisted of 380 students between 7th and 9th grade, with an average age of 13.56 ± 1.23 years in the school year 2011/2012, from a 2nd and 3rd Cycle Basic School of the municipality of Viseu, Portugal. Findings: School performance in adolescents was associated with better subjective quality of sleep (p=0.000), with longer sleep duration (p=0.000), with watching tv/video before sleep (p=0.000), with the habit of studying before bedtime (p=0.012), with no computer use (p=0.013) and with reading habits before bed (p=0.000). School performance was also associated with adolescents who reported not feeling sleepy during class. The teenagers who sleep more and better, and who watch tv/video, study, do not use computers, and who read before going to bed, have a better school performance.

The Scored Patient-Generated Subjective Global Assessment (PG-SGA) and its Association with Quality of Life in Ambulatory Patients Receiving Radiotherapy

OBJECTIVE: To evaluate the scored Patient-generated Subjective Global Assessment (PG-SGA) tool as an outcome measure in clinical nutrition practice and determine its association with quality of life (QoL). DESIGN: A prospective 4 week study assessing the nutritional status and QoL of ambulatory patients receiving radiation therapy to the head, neck, rectal or abdominal area. SETTING: Australian radiation oncology facilities. SUBJECTS: Sixty cancer patients aged 24-85 y. INTERVENTION: Scored PG-SGA questionnaire, subjective global assessment (SGA), QoL (EORTC QLQ-C30 version 3). RESULTS: According to SGA, 65.0% (39) of subjects were well-nourished, 28.3% (17) moderately or suspected of being malnourished and 6.7% (4) severely malnourished. PG-SGA score and global QoL were correlated (r=-0.66, P<0.001) at baseline. There was a decrease in nutritional status according to PG-SGA score (P<0.001) and SGA (P<0.001); and a decrease in global QoL (P<0.001) after 4 weeks of radiotherapy. There was a linear trend for change in PG-SGA score (P<0.001) and change in global QoL (P=0.003) between those patients who improved (5%) maintained (56.7%) or deteriorated (33.3%) in nutritional status according to SGA. There was a correlation between change in PG-SGA score and change in QoL after 4 weeks of radiotherapy (r=-0.55, P<0.001). Regression analysis determined that 26% of the variation of change in QoL was explained by change in PG-SGA (P=0.001). CONCLUSION: The scored PG-SGA is a nutrition assessment tool that identifies malnutrition in ambulatory oncology patients receiving radiotherapy and can be used to predict the magnitude of change in QoL.

An investigation of the relationship between subjective sleep quality, loneliness and mood in an Australian sample: Can daily routine explain the links?

Background: Loneliness and low mood are associated with significant negative health outcomes including poor sleep, but the strength of the evidence underlying these associations varies. There is strong evidence that poor sleep quality and low mood are linked, but only emerging evidence that loneliness and poor sleep are associated. Aims: To independently replicate the finding that loneliness and poor subjective sleep quality are associated and to extend past research by investigating lifestyle regularity as a possible mediator of relationships, since lifestyle regularity has been linked to loneliness and poor sleep. Methods: Using a cross-sectional design, 97 adults completed standardized measures of loneliness, lifestyle regularity, subjective sleep quality and mood. Results: Loneliness was a significant predictor of sleep quality. Lifestyle regularity was not a predictor of, nor associated with, mood, sleep quality or loneliness. Conclusions: This study provides an important independent replication of the association between poor sleep and loneliness. However, the mechanism underlying this link remains unclear. A theoretically plausible mechanism for this link, lifestyle regularity, does not explain the relationship between loneliness and poor sleep. The nexus between loneliness and poor sleep is unlikely to be broken by altering the social rhythm of patients who present with poor sleep and loneliness.

Instrument for simultaneous assessment of tear film surface quality and subjective vision

To develop and test a custom-built instrument to simultaneously assess tear film surface quality (TFSQ) and subjective vision score (SVS).