The electrical stimulation of appropriate components of the human visual system can result in the perception of blobs of light (or phosphenes) in totally blind patients. By stimulating an array of closely aligned electrodes it is possible for a patient to perceive very low-resolution images from spatially aligned phosphenes. Using this approach, a number of international research groups are working toward developing multiple electrode systems (called Artificial Human Vision (AHV) systems or visual prostheses) to provide a phosphene-based substitute for normal human vision. Despite the great promise, there are currently a number of constraints with current AHV systems. These include limitations in the number of electrodes which can be implanted and the perceived spatial layout and display frequency of phosphenes. Therefore the development of computer vision techniques that can maximise the visualisation value of the limited number of phosphenes would be useful in compensating for these constraints. The lack of an objective method for comparing different AHV system displays, in addition to comparing AHV systems and other blind mobility aids (such as the long cane), has been a significant problem for AHV researchers. Finally, AHV research in Australia and many other countries relies strongly on theoretical models and animal experimentation due to the difficult of prototype human trials. Because of this constraint the experiments conducted in this thesis were limited to simulated AHV devices with normally sighted research participants and the true impact on blind people can only be regarded as approximated. In light of these constraints, this thesis has two general aims. The first aim is to investigate, evaluate and develop effective techniques for mobility assessment which will allow the objective comparison of different AHV system phosphene presentation methods. The second aim is to develop a useful display framework to guide the development of AHV information presentation, and use this framework to guide the development of an AHV simulation device. The first research contribution resulting from this work is a conceptual framework based on literature reviews of blind and low vision mobility, AHV technology, and computer vision. This framework incorporates a comprehensive number of factors which affect the effectiveness of information presentation in an AHV system. Experiments reported in this thesis have investigated a number of these factors using simulated AHV with human participants. It has been found that higher spatial resolution is associated with accurate walking (reduced veering), whereas higher display rate is associated with faster walking speeds. In this way it has been demonstrated that the conceptual framework supports and guides the development of an adaptive AHV system, with the dynamic adjustment of display properties in real-time. The second research contribution addresses mobility assessment which has been identified as an important issue in the AHV literature. This thesis presents the adaptation of a mobility assessment method from the blind and low vision literature to measure simulated AHV mobility performance using real-time computer based analysis. This method of mobility assessment (based on parameters for walking speed, obstacle contacts and veering) is demonstrated experimentally in two different indoor mobility courses. These experiments involved sixty-five participants wearing a head-mounted simulation device. The final research contribution in this thesis is the development and evaluation of an original real-time looming obstacle detector, based on coarse optical flow, and implemented on a Windows PocketPC based Personal Digital Assistant (PDA) using a CF card camera. PDA based processors are a preferred main processing platform for AHV systems due to their small size, light weight and ease of software development. However, PDA devices are currently constrained by restricted random access memory, lack of a floating point unit and slow internal bus speeds. Therefore any real-time software needs to maximise the use of integer calculations and minimise memory usage. This contribution was significant as the resulting device provided a selection of experimental results and subjective opinions.

Nous nous intéressons à l'interaction dans le contexte de la Réalité Augmentée sur dispositifs mobiles. Le dispositif mobile est utilisé comme une lentille magique qui 'augmente' la perception de l'environnement physique avec du contenu numérique. Nous nous sommes particulièrement intéressés aux relations spatiales entre le contenu affiché à l'écran et l'environnement physique. En effet la combinaison des environnements physique et numérique repose sur ces relations spatiales, comme l'adaptation de l'augmentation numérique en fonction de la localisation de l'utilisateur. Mais ces relations spatiales définissent aussi des contraintes pour l'interaction. Par exemple l'effet des tremblements naturels de la main rend instable la vidéo affichée sur l'écran du dispositif mobile et par conséquent a un impact direct sur la précision d'interaction. La question est alors, comment peut-on relâcher ces contraintes spatiales pour améliorer l'interaction sans pour autant casser la co-localisation physique-numérique. Nous apportons trois contributions. Tout d'abord, nous avons établi un espace de conception décrivant le contenu affiché à l'écran dans le contexte de la Réalité Augmentée sur dispositifs mobiles. Cet espace conceptuel met en exergue les relations spatiales entre les différents repères des composants le structurant. Cet espace permet d'étudier systématiquement la conception de techniques d'interaction dans le contexte de la Réalité Augmentée sur dispositifs mobiles. Deuxièmement, nous avons conçu des techniques de pointage améliorant la précision du pointage en Réalité Augmentée sur supports mobiles. Ces techniques de pointage ont été évaluées lors d'expériences utilisateur. Enfin, dans le cadre du projet en partenariat AIST-Tuskuba, Schneider France et Schneider Japon dans lequel s'inscrit cette thèse, nous avons développé une boîte à outils pour le développement d'applications de Réalité Augmentée sur dispositifs mobiles. Cette boîte à outils a été utilisée pour développer plusieurs démonstrateurs. / We explored interaction within the context of handheld Augmented Reality (AR), where a handheld device is used as a physical magic lens to 'augment' the physical surrounding. We focused, in particular, on the role of spatial relations between the on-screen content and the physical surrounding. On the one hand, spatial relations define opportunities for mixing environments, such as the adaptation of the digital augmentation to the user's location. On the other hand, spatial relations involve specific constraints for interaction such as the impact of hand tremor on on-screen camera image stability. The question is then, how can we relax spatial constraints while maintaining the feeling of digital-physical collocation. Our contribution is three-fold. First, we propose a design space for handheld AR on-screen content with a particular focus on the spatial relations between the different identified frames of reference. This design space defines a framework for systematically studying interaction with handheld AR applications. Second, we propose and evaluate different handheld AR pointing techniques to improve pointing precision. Indeed, with handheld AR set-up, both touch-screen input and the spatial relations between the on-screen content and the physical surrounding impair the precision of pointing. Third, as part of a collaborative research project involving AIST-Tsukuba and Schneider- France and Japan, we developed a toolkit supporting the development of handheld AR applications. The toolkit has been used to develop several demonstrators.

Made available in DSpace on 2016-03-15T19:37:33Z (GMT). No. of bitstreams: 1 Valmir Fernandes Junior.pdf: 2218220 bytes, checksum: f12b7829c2024510149ca8f24aa66e26 (MD5) Previous issue date: 2010-08-10 / This paper presents a technique to iris detection and tracking that can be used in a human computer interface which allows people with mobility restricted, including no mobility above the shoulders, can control the mouse pointer only moving their eyes, without using expensive equipments. The unique data input used is an ordinary webcam without optical zoon, special lights or restricting user face mobility. The mouse displacement will occur in a straight way, in other words, the mouse cursor will be positioned at the place estimated by the technique. To the iris detection tests 60 images were used. 90.83% of the iris were identified correctly, there were 4.17% of missing iris and 5% false positives (iris were estimated in a wrong place). Using images generated straight from the webcam the iris were found correctly in 87,5%, no iris were found in 11,11% and in 1,39% the technique found iris in wrong places, the average time between positioning and a click is about 20 seconds. / Este trabalho apresenta uma técnica de detecção e rastreamento de íris para ser utilizada em uma interface homem-computador que permita pessoas com mobilidade restrita, inclusive sem mobilidade nos ombros, possam controlar o cursor do mouse com o movimento dos olhos, sem a necessidade de adquirir equipamentos caros. A única entrada de dados utilizada é uma webcam simples sem auxílio de zoon ótico, iluminação especial ou fixação da face do usuário. A movimentação do mouse dar-se-á de maneira direta, ou seja, o ponteiro do mouse será direcionado para a região estimada pela técnica. Para a realização dos testes de detecção de íris foram utilizadas 60 imagens. Em 90.83% dos casos as íris foram encontradas corretamente, 4.17% dos casos não foram identificados e ocorreram 5% de falsos positivos (casos em que as íris foram estimadas no lugar errado). Com as imagens geradas diretamente pela webcam a identificação das íris ocorreu com sucesso em 87,50% dos casos, erros em 11,11 % e 1,39% de falsos positivos, o tempo médio entre o posicionamento e um clique é de cerca de 20 segundos.

As industry becomes increasingly reliant on robotic assistance and human-computer interfaces, the demand to understand the human sensorimotor system’s characteristics intensifies. Although this field of research has been going on for over a century, new technologies push the limits of the human motor system and our knowledge of it. With new technologies come new abilities, and, in the area of medical care and rehabilitation, the need to expand our knowledge of the sensorimotor system comes from both the patient and physician. Two studies relating to human force interaction are presented in this thesis. The first study focuses on humans’ ability to bimanually recreate forces. That is, to feel a force on one hand and reproduce that force on the other. This skill is applicable in everyday lives from tasks such as a gardener using shears to trim a bush to a surgeon tying a delicate suture. These two tasks illustrate the different factors in this study on force recreation, which are the effects of: (1) occupational force dexterity, (2) force magnitude, and (3) the number of fingers used in the recreation task. Results showed statistical significance for force magnitude and number of fingers as factors in bimanual force recreation but not for occupation. The second study examines how humans compensate for force perturbations in different directions with respect to the line of action and the effects of restricting movement time. A dynamic tracking task was presented to participants in which they were told to follow a moving target as accurately as possible. During a fixed interval along the target’s path, a force field would perturb them in an undisclosed direction. Nine force conditions and three speeds were tested on both the left and right hands. Statistical analyses and comparison of error data indicate an effect of force direction on compensation accuracy. Speed is demonstrated as a statistically significant factor on accuracy, and a linear relationship between speed and error is posited.

Modern facial feature tracking techniques can automatically extract and accurately track multiple facial landmark points from faces in video streams in real time. Facial landmark points are defined as points distributed on a face in regards to certain facial features, such as eye corners and face contour. This opens up for using facial feature movements as a handsfree human-computer interaction technique. These alternatives to traditional input devices can give a more interesting gaming experience. They also open up for more intuitive controls and can possibly give greater access to computers and video game consoles for certain disabled users with difficulties using their arms and/or fingers. This research explores using facial feature tracking to control a character's movements in a platform game. The aim is to interpret facial feature tracker data and convert facial feature movements to game input controls. The facial feature input is compared with other handsfree inputmethods, as well as traditional keyboard input. The other handsfree input methods that are explored are head pose estimation and a hybrid between the facial feature and head pose estimation input. Head pose estimation is a method where the application is extracting the angles in which the user's head is tilted. The hybrid input method utilises both head pose estimation and facial feature tracking. The input methods are evaluated by user performance and subjective ratings from voluntary participants playing a platform game using the input methods. Performance is measured by the time, the amount of jumps and the amount of turns it takes for a user to complete a platform level. Jumping is an essential part of platform games. To reach the goal, the player has to jump between platforms. An inefficient input method might make this a difficult task. Turning is the action of changing the direction of the player character from facing left to facing right or vice versa. This measurement is intended to pick up difficulties in controling the character's movements. If the player makes many turns, it is an indication that it is difficult to use the input method to control the character movements efficiently. The results suggest that keyboard input is the most effective input method, while it is also the least entertaining of the input methods. There is no significant difference in performance between facial feature input and head pose input. The hybrid input version has the best results overall of the alternative input methods. The hybrid input method got significantly better performance results than the head pose input and facial feature input methods, while it got results that were of no statistically significant difference from the keyboard input method. Keywords: Computer Vision, Facial Feature Tracking, Head Pose Tracking, Game Control / Moderna tekniker kan automatiskt extrahera och korrekt följa multipla landmärken från ansikten i videoströmmar. Landmärken från ansikten är definerat som punkter placerade på ansiktet utefter ansiktsdrag som till exempel ögat eller ansikts konturer. Detta öppnar upp för att använda ansiktsdragsrörelser som en teknik för handsfree människa-datorinteraktion. Dessa alternativ till traditionella tangentbord och spelkontroller kan användas för att göra datorer och spelkonsoler mer tillgängliga för vissa rörelsehindrade användare. Detta examensarbete utforskar användbarheten av ansiktsdragsföljning för att kontrollera en karaktär i ett plattformsspel. Målet är att tolka data från en appliktion som följer ansiktsdrag och översätta ansiktsdragens rörelser till handkontrollsinmatning. Ansiktsdragsinmatningen jämförs med inmatning med huvudposeuppskattning, en hybrid mellan ansikstdragsföljning och huvudposeuppskattning, samt traditionella tangentbordskontroller. Huvudposeuppskattning är en teknik där applikationen extraherar de vinklar användarens huvud lutar. Hybridmetoden använder både ansiktsdragsföljning och huvudposeuppskattning. Inmatningsmetoderna granskas genom att mäta effektivitet i form av tid, antal hopp och antal vändningar samt subjektiva värderingar av frivilliga testanvändare som spelar ett plattformspel med de olika inmatningsmetoderna. Att hoppa är viktigt i ett plattformsspel. För att nå målet, måste spelaren hoppa mellan plattformar. En inefektiv inmatningsmetod kan göra detta svårt. En vändning är när spelarkaraktären byter riktning från att rikta sig åt höger till att rikta sig åt vänster och vice versa. Ett högt antal vändningar kan tyda på att det är svårt att kontrollera spelarkaraktärens rörelser på ett effektivt sätt. Resultaten tyder på att tangentbordsinmatning är den mest effektiva metoden för att kontrollera plattformsspel. Samtidigt fick metoden lägst resultat gällande hur roligt användaren hade under spelets gång. Där var ingen statisktiskt signifikant skillnad mellan huvudposeinmatning och ansikstsdragsinmatning. Hybriden mellan ansiktsdragsinmatning och huvudposeinmatning fick bäst helhetsresultat av de alternativa inmatningsmetoderna. Nyckelord: Datorseende, Följning av Ansiktsdrag, Följning av Huvud, Spelinmatning

As pessoas com deficiência compreendem uma parcela da população as quais as formas de planejamento dos espaços urbanos causam impacto direto em sua qualidade de vida, sendo a incapacidade visual a mais abrangente entre as deficiências, acometendo mais de 35 milhões de pessoas no Brasil. Nas últimas décadas, as normas e leis brasileiras de promoção da acessibilidade buscam criar condições para que as pessoas com deficiências possam ter uma vida social e econômica mais ativa, por meio do uso dos preceitos do design universal nos projetos de acessibilidade para espaços públicos e meios de transporte. No entanto, definir regulamentos e normas tem se mostrado insuficiente, pois a simples padronização de recursos físicos, como pisos táteis, não garantem a autonomia para o deslocamento das pessoas com deficiência visual. Paralelo às adequações dos espaços públicos para a acessibilidade, algumas tecnologias eletrônicas têm sido desenvolvidas de forma efetiva para o design universal, dentre elas as atuais formas de audiodescrição de programas de TV, cinemas e teatros, assim como o desenvolvimento de tecnologias de voz sintetizada para quepessoas com deficiência visual possam fazer uso dos portáteis smartphones. Neste estudo, foram realizadas pesquisas bibliográficas e experimentos em ambientes controlados e ambientes públicos, utilizando-se de técnicas de pesquisa qualitativa para o levantamento, registro e análise de informações, por meio da observação de voluntários com deficiência visual, enquanto utilizavam um modelo primordial de equipamento com voz digital para orientá-los em três ambientes públicos na cidade de São Paulo, compreendendo uma movimentada estação de metrô, uma calçada a céu aberto e uma instituição pública de cultura. Os experimentos demonstraram que os voluntários com deficiência visual podem utilizar um formato adequado de audiodescrição para a orientação e mobilidade, contanto que sejam consideradas peculiaridades que relacionem a velocidade de marcha de pessoas com deficiência visual com os processos cognitivos pertinentes à audição e à percepção ambiental. Por consequência, esta pesquisa oferece princípios para o design de audionavegação, por meio de readequações na audiodescrição para abranger os conceitos de orientação e mobilidade, de modo a possibilitar sua aplicação em projetos de interfaces eletrônicas portáteis com voz sintetizada para orientar pessoas com deficiência visual, buscando assim um incrementando na autonomia dessas pessoas para seu wayfinding em ambientes públicos e transportes de massa. / The people with disabilities comprise a portion of the population whose forms of planning in urban spaces have a direct impact on their quality of life, with visual impairment being the most comprehensive among disabilities, affecting more than35 million individuals in Brazil. In the last decades, the Brazilian norms and laws to promote accessibility seek to create conditions for people with disabilities to have a more active social and economic life, through the use of universal design precepts in the projects of accessibility for public spaces and mass transports. However, setting regulations and norms has proved insufficient, since the simple standardization of physical resources, such as tactile floors, do not guarantee autonomy for the displacement of visually impaired people. Parallel to the adaptations of public spaces for accessibility, some electronic technologies have been effectively developed for the universal design, amongst them the present forms of audiodescription of TV programs, cinemas and theaters, as well as the development of synthesized voice technologies so that people with visual disabilities can make use of portable smartphones. In this study, in addition to relevant bibliographical research, practical experiments were carried out in controlled and public environments, applying qualitative research techniques for the collection, recording and analysis of information through the observation of volunteers with visual impairment, using a primordial model of equipment with digital voice technology to guide them in three public spaces in the city of São Paulo, comprising a busy subway station, a sidewalk and a public cultural institution. The experiments have shown that visually impaired volunteers can use an appropriate format of audiodescription for orientation and mobility, as long as they are considered peculiarities that relate the visually impaired people walking speed to cognitive processes relevant to hearing and for environmental perception. As a result, this research offers principles for the audionavigation design, through adjustments in audiodescription to include the orientation and mobility concepts, enabling its application in projects of portable electronic interfaces with synthesized voice to guide visually impaired people, seeking an increase in wayfinding autonomy for these people when in public environments and mass transports.

A pesquisa explora a intersecção entre o design de informação e os estudos acerca do fenômeno urbano, considerando o avanço recente das tecnologias voltadas à representação e as possibilidades que trazem à comunicação visual. É proposta uma introdução ao tema da cidade, abordada tanto de uma perspectiva macro, que busca embasamento nas ciências, quanto do ponto de vista da experiência urbana de seus usuários. Em seguida, são investigadas as possibilidades do design de informação nesse contexto, por meio de uma revisão bibliográfica da teoria relacionada ao tema e da análise de projetos e iniciativas que buscam aproximar, por meio do design e do uso de ambientes virtuais, conjuntos de dados e informações da cognição humana. Com relação às tecnologias, são investigadas ferramentas de representação da informação urbana, envolvendo visualização de dados, interação humano-computador e navegação por ambientes tridimensionais. Em um paralelo com a arquitetura, são observadas formas como a informação tem sido espacializada em ambientes físicos e virtuais. Por fim, o trabalho propõe investigações práticas, de modo a explorar particularidades de algumas das ferramentas disponíveis, e pondera sobre a atuação do designer na representação da informação urbana à luz das questões estudadas. / This research explores the intersection between information design and studies on urban phenomena, considering the recent developments in technologies of representation and possibilities that they bring to visual comunication. An introduction to the theme of the city is proposed, viewed both from a macro perspective, that seeks grounding in science, and from the perspective of the user experience. Then, are investigated the possibilities of information design in this context, trough a literature review of the theme and analysis of information design projects that seek to approach urban issues and human cognition. With regard to digital technologies, the representation of urban information evolving automatized data visualization, human-computer interaction and navigation in 3D environments are investigated. In a parallel with architecture, ways in which information has been spatialized in physical and virtual environments are observed. Lastly, the research proposes a practical investigation, to explore particularities of some available tools and to consider the role of designers on representation of urban information, taking into account the studied issues.

Nos últimos anos observa-se um intenso debate acerca da transição da TV analógica para a TV digital, acompanhada pela incorporação de inúmeras inovações, dentre as quais destacamos a interatividade, que abre uma nova modalidade para este meio de comunicação, a TV interativa. Os desafios de pesquisa e desenvolvimento em TV interativa são amplos e ainda não totalmente investigados. Em particular, a questão da consistência de interfaces com usuário se apresenta como um tópico relevante e pouco explorado na literatura. Esta dissertação investiga a questão da consistência da interface com o usuário para a TV interativa, considerando seus aspectos teóricos e de implementação. Para tanto investigamos na literatura de Interfaces Humano-Computador a questão da consistência e suas abordagens. Considerando que a consistência é uma característica relativa a um modelo, buscamos identificar modelos de interfaces de TV interativa que sejam exemplos de boas práticas a serem seguidas. A metodologia proposta e utilizada é composta por cinco etapas, a saber: modelagem do usuário, análise de tarefas, diretrizes gerais de interface, análise comparativa de plataformas e coordenação da interface. As três primeiras etapas geram recomendações enquanto que a etapa de análise comparativa gera referências. Utilizando estes dois subsídios a etapa de coordenação da interface objetiva elencar exemplos de interfaces que possam se tornar modelos, esta etapa também verifica a consistência interna do modelo proposto e elabora alternativas no caso das soluções encontradas não serem satisfatórias. No âmbito desta metodologia realizamos extensas avaliações experimentais, dentre as quais destacamos a proposta de quatro modelos de usuário (Torcedor Antenado, Mãe Ocupada, Meia Idade com Ajuda e Torcedor com Baixa Alfabetização), uma análise contextual de tarefas envolvendo dois dos quatro modelos de usuário propostos, bem como uma extensa análise comparativa entre sete plataformas de TV. Este trabalho resultou numa proposta integrada de interface que abrange três aspectos: um mapa de navegação, um conjunto mínimo de teclas para o controle remoto e um modelo de navegação. O mapa de navegação apresenta a taxonomia do sistema. O conjunto mínimo de teclas compreende os recursos mínimos que devem estar universalmente disponíveis ao usuário. O modelo de navegação apresenta uma forma consistente e extensível de navegação para ser utilizada em aplicativos de TV interativa. / In the past few years there has been an intense debate about the transition from analog to digital Television, with the acquisition of many innovations. Of particular interest to this study is the interactivity, which opens a new modality for this medium, the interactive TV. The challenges posed by research and development in interactive TV are ample and not fully investigated. In particular, the question of user interface consistency presents itself as a relevant topic, which is little explored in the literature. This work investigates the question of user interface consistency for interactive TV, taking into account it\'s theoretical and implementation implications. The question of consistency and its approaches was reviewed in the literature of Human-Computer Interfaces. Considering that consistency is a characteristic relative to a model, we tried to identify models of interactive TV interfaces, which are examples of best practices to be followed. The methodology proposed and utilized has five steps: user modeling, task analysis, interface guidelines, platform comparative analysis and interface coordination. The first three steps generate recommendations while the comparative analysis generates references. Using these two products the interface coordination tries to determine examples of interfaces, which can become models, this step also verifies the internal consistency of the proposed model and elaborates alternatives if the found solutions are not satisfactory. Using this methodology a large experimental evaluation was performed. Of special interest is the proposition of four user models, a contextual task analysis of two of the user models as well as an extensive comparative analysis between seven TV platforms. The result of this work is the proposition of an integrated interface, which focuses on three aspects: the navigation map, the minimum remote and a navigation model. The navigation map is the taxonomy of the system. The minimum remote is a group of keys that should be universally available to the user. The navigation model presents a consistent and extensible mechanism for navigation in interactive TV applications.

A usabilidade é um requisito valioso para os produtos de Sistemas de Informação. A avaliação de usabilidade está cada vez mais se tornando uma parte importante do processo de desenvolvimento de software. O objetivo deste trabalho é propôr uma abordagem para suportar avaliação de usabilidade de sistemas web por meio da análise de arquivos de log dos servidores web. A metodologia desenvolvida neste trabalho consiste em filtrar arquivos de log, para capturar as tarefas realizadas, e comparar com um modelo descritivo das tarefas possíveis de serem desempenhadas em um website. As tarefas realizadas são descritas pelos recursos web essenciais para o cumprimento dessas tarefas. As métricas de usabilidade obtidas deste processo podem indicar possíveis problemas de usabilidade. Métodos de avaliação de usabilidade mais detalhados podem ser aplicados para verificar ou não se estes problemas realmente ocorrem. Além disso, a comparação de métricas permite identificar o quanto positivas foram algumas mudanças com relação à eficácia e à eficiência na interação com o website em avaliação. Este trabalho resultou no desenvolvimento de uma ferramenta que recebe um arquivo de log referente a um website, filtra seu conteúdo, de acordo com páginas web relacionadas a tarefas previamente cadastradas, e calcula métricas que quantifiquem a usabilidade do website avaliado. / Usability is a valuable requirement for Information Systems products. Usability evaluation is increasingly becoming an important part of software development process. The objective of this work is to propose an approach for supporting usability evaluation of web systems by analyzing log files of web servers. The methodology developed in this work is to filter log files, to capture the tasks performed, and compare with a model describing the possible tasks to be performed on a website. The tasks performed are described by web resources essential to the fulfillment of these tasks. The usability metrics obtained by this process can indicate possible usability problems. More detailed usability evaluation methods may be applied to verify whether or not these problems do occur. Furthermore, comparison of metrics identifies how positive some changes were with respect to the effectiveness and the efficiency of the interaction with the website in evaluation. This work resulted in the development of a tool that receives a log file relating to a website, filter content, according to web pages related tasks previously registered, and calculate metrics that quantify the usability of the evaluated website.

A usabilidade é um requisito valioso para os produtos de Sistemas de Informação. A avaliação de usabilidade está cada vez mais se tornando uma parte importante do processo de desenvolvimento de software. O objetivo deste trabalho é propôr uma abordagem para suportar avaliação de usabilidade de sistemas web por meio da análise de arquivos de log dos servidores web. A metodologia desenvolvida neste trabalho consiste em filtrar arquivos de log, para capturar as tarefas realizadas, e comparar com um modelo descritivo das tarefas possíveis de serem desempenhadas em um website. As tarefas realizadas são descritas pelos recursos web essenciais para o cumprimento dessas tarefas. As métricas de usabilidade obtidas deste processo podem indicar possíveis problemas de usabilidade. Métodos de avaliação de usabilidade mais detalhados podem ser aplicados para verificar ou não se estes problemas realmente ocorrem. Além disso, a comparação de métricas permite identificar o quanto positivas foram algumas mudanças com relação à eficácia e à eficiência na interação com o website em avaliação. Este trabalho resultou no desenvolvimento de uma ferramenta que recebe um arquivo de log referente a um website, filtra seu conteúdo, de acordo com páginas web relacionadas a tarefas previamente cadastradas, e calcula métricas que quantifiquem a usabilidade do website avaliado. / Usability is a valuable requirement for Information Systems products. Usability evaluation is increasingly becoming an important part of software development process. The objective of this work is to propose an approach for supporting usability evaluation of web systems by analyzing log files of web servers. The methodology developed in this work is to filter log files, to capture the tasks performed, and compare with a model describing the possible tasks to be performed on a website. The tasks performed are described by web resources essential to the fulfillment of these tasks. The usability metrics obtained by this process can indicate possible usability problems. More detailed usability evaluation methods may be applied to verify whether or not these problems do occur. Furthermore, comparison of metrics identifies how positive some changes were with respect to the effectiveness and the efficiency of the interaction with the website in evaluation. This work resulted in the development of a tool that receives a log file relating to a website, filter content, according to web pages related tasks previously registered, and calculate metrics that quantify the usability of the evaluated website.