Methods for the transfer function design of multiple narrow-band bandpass sigma-delta modulators

This paper presents the design analysis of novel tunable narrow-band bandpass sigma-delta modulators, which can achieve concurrent multiple noise-shaping for multi-tone input signals. Four different design methodologies based on the noise transfer functions of comb filters, slink filters, multi-notch filters and fractional delay comb filters are applied for the design of these multiple-band sigma-delta modulators. The latter approach utilises conventional comb filters in conjunction with FIR, or allpass IIR fractional delay filters, to deliver the desired nulls for the quantisation noise transfer function. Detailed simulation results show that FIR fractional delay comb filter-based sigma-delta modulators tune accurately to most centre frequencies, but suffer from degraded resolution at frequencies close to Nyquist. However, superior accuracies are obtained from their allpass IIR fractional delay counterpart at the expense of a slight shift in noise-shaping bands at very high frequencies. The merits and drawbacks of each technique for the various sigma-delta topologies are assessed in terms of in-band signal-to-noise ratios, accuracy of tunability and coefficient complexity for ease of implementation.

Program slice metrics and their potential role in DSL design, position paper

The advantages a DSL and the benefits its use potentially brings imply that informed decisions on the design of a domain specific language are of paramount importance for its use. We believe that the foundations of such decisions should be informed by analysis of data empirically collected from systems to highlight salient features that should then form the basis of a DSL. To support this theory, we describe an empirical study of a large OSS called Barcode, written in C, and from which we collected two well-known 'slice' based metrics. We analyzed multiple versions of the system and sliced its functions in three separate ways (i.e., input, output and global variables). The purpose of the study was to try and identify sensitivities and traits in those metrics that might inform features of a potential slice-based DSL. Results indicated that cohesion was adversely affected through the use of global variables and that appreciation of the role of function inputs and outputs can be revealed through slicing. The study presented is motivated primarily by the problems with current tools and interfaces experienced directly by the authors in extracting slicing data and the need to promote the benefits that analysis of slice data and slicing in general can offer.

An FPGA based decimation filter processor design for real-time continuous-time Σ−Δ modulator performance measurement and evaluation

This paper reports on a Field Programmable Gate Array (FPGA) implementation as well as prototyping for real-time testing of a low complexity high efficiency decimation filter processor which is deployed in conjunction with a custom built low-power jitter insensitive Continuous Time (CT) Sigma-Delta (Σ-Δ) Modulator to measure and assess its performance. The CT Σ-Δ modulator/decimation filter cascade can be used in integrated all-digital microphone interfaces for a variety of applications including mobile phone handsets, wireless handsets as well as other applications requiring all-digital microphones. The work reported here concentrates on the design and implementation as well as prototyping on a Xilinx Spartan 3 FPGA development system and real-time testing of the decimation processing part deploying All-Pass based structures to process the bit stream coming from CT Σ-Δ modulator hence measuring in real-time and fully assessing the modulator's performance.

Contributo do design nos dispositivos de intervenção cirúrgica

Hoje em dia a técnica de cirurgia laparoscópica é bastante comum no tratamento de várias doenças ao nível do abdómen. Um ponto forte em relação a outras técnicas cirúrgicas é a rápida recuperação do paciente após a cirurgia, como também o fato de as marcas provocadas pela cirurgia serem bastante mais discretas. Sendo assim, é de elevada importância que esta técnica evolua e seja aperfeiçoada para que o erro humano seja minimizado e o tratamento dos pacientes melhorado. As dificuldades encontradas na realização destas cirurgias são causa direta dos tipos de instrumentos utilizados, sendo a interação com os aparelhos um fator importante para que a intervenção cirúrgica seja realizada com sucesso. Como tal, devido a natureza ergonómica dos instrumentos, os cirurgiões sentem dificuldades na execução das suas tarefas ao longo da cirurgia, acusando dores musculares nas mãos e nos braços. Este trabalho tem como principal objetivo melhorar este tipo de cirurgia através do design aliado à ergonomia de aparelhos manuais, tendo as formas e funções dos instrumentos existentes como base de estudo para a criação de um aparelho mais ergonómico e eficaz. Também a existência de tecnologias capazes de reproduzir os conceitos criados pelo designer são uma mais valia para a criação das formas desenvolvidas. Desta forma, ao longo do desenvolvimento do produto são tidas em conta questões de ergonomia, mas também a higiene é considerada de relativa importância devido a facilidade de transmissão de doenças através do toque, sendo assim pertinente ter em consideração os pré requisitos necessários para a criação de um aparelho de natureza cirúrgica. O protótipo criado possui um componente eletromecânico já desenvolvido para este tipo de intervenção cirúrgica, desta forma o desenvolvimento da carcaça tem a forma do corpo eletromecânico como base para a criação da melhor ergonomia possível. Esta segue um conceito minimalista e orgânico, procurando adaptar-se à mão do utilizador com o intuito de proporcionar um melhor manuseio do aparelho e através das interfaces conferir uma utilização intuitiva, mais eficaz e menos demorada.

Estudo da percepção dos problemas de usabilidade de um software relacionados com o desempenho dos processos cognitivos

Dissertação apresentada à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Audiovisual e Multimédia.

Narrative Bifurcation, Cloud Computing Interfaces and Hitchcok

From a narratological perspective, this paper aims to address the theoretical issues concerning the functioning of the so called «narrative bifurcation» in data presentation and information retrieval. Its use in cyberspace calls for a reassessment as a storytelling device. Films have shown its fundamental role for the creation of suspense. Interactive fiction and games have unveiled the possibility of plots with multiple choices, giving continuity to cinema split-screen experiences. Using practical examples, this paper will show how this storytelling tool returns to its primitive form and ends up by conditioning cloud computing interface design.

Les personnes âgées face au défi d'utilisation des nouvelles technologies : étude de l’utilisabilité des interfaces de téléphones portables

L’évolution technologique et l'accroissement de la population vieillissante sont deux tendances majeures de la dernière décennie. Durant cette période, la prolifération ubiquitaire de la téléphonie mobile a changé les habitudes de communication des gens. Le changement constant des appareils téléphoniques portatifs, l'augmentation des fonctions, la diversité iconographique, la variété des interfaces et la complexité de navigation exigent aujourd’hui non seulement plus de temps d'adaptation et d’apprentissage, mais représentent aussi un effort cognitif important. Les technologies d'information et de communication (TIC) sont devenues des outils incontournables de la vie moderne. Pour les personnes âgées, cet univers en perpétuelle mutation avec ces nouveaux appareils représente un obstacle à l’accès à l’information et contribue ainsi au gap générationnel. Le manque de référence et de soutien et les déficiences physiques ou cognitives, que certaines personnes développent en vieillissant, rendent l'usage de ce type d’objet souvent impossible. Pourtant, les produits intelligents plus accessibles, tant au niveau physique que cognitif sont une réelle nécessité au sein de notre société moderne permettant aux personnes âgées de vivre de manière plus autonome et « connectée ». Cette recherche a pour but d'exposer les défis d'usage des téléphones portables existants et d'identifier en particulier les problèmes d’usage que les personnes âgées manifestent. L’étude vise la tranche de population qui est peu habituée aux technologies de communications qui ne ciblent le plus souvent que les plus jeunes et les professionnels. C’est en regardant les habitudes d’usage, que la recherche qualitative nous permettra d’établir un profil des personnes âgées par rapport au TIC et de mieux comprendre les défis liés à la perception, compréhension et l’usage des interfaces de téléphones portables.

Le rôle des interfaces dans l’expérience de jeu vidéo : le jeu du ping-pong et son adaptation sur des plateformes numériques

Le succès commercial des jeux vidéo nous montre qu’ils sont devenus une alternative non négligeable en matière de loisir et de divertissement. En observant les tendances, on constate que les concepteurs de jeux vidéo cherchent à transposer ou adapter les loisirs comme la danse, l’interprétation de la musique ou la pratique d’un sport dans le contexte de jeux vidéo (l’univers virtuel) et ceci est devenu encore plus évident depuis l’apparition des nouvelles technologies intégrant le mouvement comme mode d'interaction. En rapport aux activités dont les jeux vidéo s’inspirent, ces tendances entraînent des changements considérables sur l’aspect formel de l’activité ludique et notamment l’interaction. Dans le cas particulier du tennis de table, ou ping-pong dans le langage courant, il semble y avoir des différences en terme de plaisir lors de la pratique de ce loisir de façon traditionnelle ou en mode virtuel dans ses différentes adaptations. Le but de cette recherche est de mettre en évidence les différences entre l’appréciation de l’interaction avec le contrôleur multifonctionnel Wiimote et une raquette traditionnelle de ping-pong et de découvrir les implications sur l’expérience du plaisir de la transposition du jeu ping-pong traditionnel comparé aux adaptations sur la console Wii. Ainsi, en regard du CLASSIC GAME MODEL de Juul (2005) et du modèle THE FOUR FUN KEYS de Lazzaro (2008) nous comparons les deux modes d’interaction, jeu traditionnel avec le jeu virtuel, sur le plan formel du jeu et sur les dimensions du plaisir que chacun procure. Les résultats obtenus par l’observation des tests de jeu et l’entremise des autres outils permettent de souligner le rôle déterminant des interfaces dans l’engagement des joueurs et de montrer les limites des interfaces digitales par rapport à celle des jeux traditionnels.

Étude empirique du contexte d’utilisation des interfaces de vidéocommunication mobile

Ce document présente les résultats d’une étude empirique sur l’utilisation de la vidéoconférence mobile selon le contexte de l’usager afin de proposer des lignes directrices pour la conception des interfaces des dispositifs de communication vidéo mobile. Grâce à un échange riche d’informations, ce type de communication peut amener un sentiment de présence fort, mais les interfaces actuelles manquent de flexibilité qui permettrait aux usagers d’être créatifs et d’avoir des échanges plus riches lors d’une vidéoconférence. Nous avons mené une recherche avec seize participants dans trois activités où leurs conversations, leurs réactions et leurs comportements ont été observés. Deux groupes de discussion ont aussi servi à identifier les habitudes développées à partir de leur utilisation régulière de la vidéoconférence. Les résultats suggèrent une différence importante entre l’utilisation de la caméra avant et la caméra arrière de l’appareil mobile, et la nécessité de fournir des outils qui offrent plus de contrôle sur l’échange dans la conversation. L’étude propose plusieurs lignes directrices de conception pour les interfaces de communication vidéo mobiles, concernant la construction du contexte mobile de l’utilisateur.

Design. Fabrication and Characterization of Fiber Optic Sensors for Physical and Chemical Applications

Advent of lasers together with the advancement in fiber optics technology has revolutionized the sensor technology. Advancement in the telemetric applications of optical fiber based measurements is an added bonus. The present thesis describes variety of fiber based sensors using techniques like micro bending, long period grating and evanescent waves. Sensors to measure various physical and chemical parameters are described in this thesis.

The DIADEM Software Development Methodology extended to Multimedia Interfaces

DIADEM, created by THOMSON-CSF, is a methodology for specifying and developing user interfaces. It improves productivity of the interface development process as well as quality of the interface. The method provides support to user interface development in three aspects. (1) DIADEM defines roles of people involved and their tasks and organises the sequence of activities. (2) It provides graphical formalisms supporting information exchange between people. (3) It offers a basic set of rules for optimum human-machine interfaces. The use of DIADEM in three areas (process control, sales support, and multimedia presentation) was observed and evaluated by our laboratory in the European project DIAMANTA (ESPRIT P20507). The method provides an open procedure that leaves room for adaptation to a specific application and environment. This paper gives an overview of DIADEM and shows how to extend formalisms for developing multimedia interfaces.

Extracting Urban Food Potential: design-based methods for digital and bodily cartography

Sweden’s recent report on Urban Sustainable Development calls out a missing link between the urban design process and citizens. This paper investigates if engaging citizens as design agents by providing a platform for alternate participation can bridge this gap, through the transfer of spatial agency and new modes of critical cartography. To assess whether this is the case, the approaches are applied to Stockholm’s urban agriculture movement in a staged intervention. The aim of the intervention was to engage citizens in locating existing and potential places for growing food and in gathering information from these sites to inform design in urban agriculture. The design-based methodologies incorporated digital and bodily interfaces for this cartography to take place. The Urban CoMapper, a smartphone digital app, captured real-time perspectives through crowd-sourced mapping. In the bodily cartography, participant’s used their bodies to trace the site and reveal their sensorial perceptions. The data gathered from these approaches gave way to a mode of artistic research for exploring urban agriculture, along with inviting artists to be engaged in the dialogues. In sum, results showed that a combination of digital and bodily approaches was necessary for a critical cartography if we want to engage citizens holistically into the urban design process as spatial agents informing urban policy. Such methodologies formed a reflective interrogation and encouraged a new intimacy with nature, in this instance, one that can transform our urban conduct by questioning our eating habits: where we get our food from and how we eat it seasonally.

Programming Principles: Abstract Classes and Interfaces

In this session we look at how to use Abstract Classes and Interfaces in Object Oriented Design - especially as a way to get all the advantages of multiple inheritance without any of the problems.

Orientaçoes para o design da interface de software educativo multimédia. 'Orientaciones para el diseño de un interfaz de software educativo multimedia'.

Conocer qué desafíos se fijan los creadores de software educativo multimedia, qué tipo de comunicación debemos establecer entre el usuario y el ordenador para que sus exploraciones desemboquen en situaciones de aprendizaje y cómo favorecer la realización de software adecuado a la naturaleza del proceso educativo en las cuales las características de accesibilidad, transparencia, atractivo, claridad de objetivos educativos y la realización de actividades, contribuyen a una mayor interactividad del hombre con la máquina. Se utilizó la investigación por compilación, con compilación documental, por entrevista y por encuesta, y la investigación documental, utilizando fuentes primarias y secundarias de información para esbozar la evolución, tendencias y orientaciones de diseño de interfaces. La investigación empírica se divide en dos estudios, el primero abordó la cuestión del nivel de conocimientos y la utilización del software educativo por parte de los maestros de Educación infantil y profesores de primaria y, el segundo, tenía como objetivo confeccionar una lista de orientaciones para el diseño de interfaces, a partir de aspectos estudiados en el marco teórico, y a partir de los cuales se diseñó una tabla de evaluación de interfaces de software educativo multimedia. El estudio se llevó a cabo con maestros y profesores de primaria que asistían al curso complementario de formación en la Escuela Superior de Educación de Fafe durante los años 1999-2000, 2000-2001, 2001-2002. Se elaboró una tabla de evaluación de interfaces destinado a los realizadores de software educativo que sirve para controlar la calidad del interfaz. Los docentes a pesar de conocer algún que otro software educativo disponible en el mercado, su uso en el contexto educativo es poco frecuente. Los profesores que estuvieron ligados a proyectos con prácticas en ordenador o que realizaron acciones de formación en Nuevas Tecnologías conocen y recurren más al software educativo.

O design e a interpretação do lugar

O modo de inventar é um acto de cultura que exige uma interacção com a imaginação e um controlo através dos dados culturais dessa mesma imaginação. O Designer move-se não tendo a garantia de eficácia dos seus movimentos, mas com dados de cultura sabe que pode controlar a imaginação, porque admite que o Design é a disciplina com a capacidade de transformar o espaço e o tempo. O Designer sabe que existe uma Teoria da Arte e uma Filosofia da Arte (que engloba todas as artes com estéticas diferentes). Em certos casos nota que há estéticas susceptíveis de serem aplicadas a várias artes, mas que há artes que desenvolvem estéticas (parece) não transmissíveis. Sabe que a poética existe e que sem ela não se consegue operar, pelo que tem de ter um programa de intervenção concreto para que a imaginação se desenvolva e se alcance um objecto concreto.