This thesis investigates embedded databases and graphical interfaces for the MicroBaseJ project. The project aim is the development of an integrated database and GUI user interface for a typical 3G, or 2.5G, mobile phone with Java MIDP2 capability. This includes methods for data acquisition, mobile data and information communication, data management, and remote user interface. Support of phone delivered informatics will require integrated server and networking infrastructure research and development to support effective and timely delivery of data for incorporation in mobile device-based informatics applications. A key research and development (R&D) challenge is to support effective and timely delivery of data for incorporation in mobile device-based informatics applications. Another important aspect of the project is determining how to develop efficient graphics for the small mobile screen. The research investigates and analyses the architecture of a mobile monitoring system. The project developed a generic solution that can be implemented in a number of commercial sectors, such as horticulture, building management and pollution/water management. The developed concept is tested using data relevant to the horticultural area of application. The system also addresses the main issues related to mobile monitoring, including real-time response, data integrity, solution cost, graphical presentation, and persistent storage capabilities of modern mobile devices. Four embedded databases based on J2ME have been investigated. Two of the four have been evaluated and analysed. The Insert function, Sequence Search, and Random Search of Perst List and RMS (Record Management System) databases have been tested. The size of the processed data was limited to 20,000 records when using the wireless toolkit simulator, and 11,000 records when using a mobile phone. Perst Lite reflects good performance and has out-performed RMS in all tests. User interface software such as J2ME Polish for mobile phones has been investigated. Custom J2ME class for graphical interface is developed. This provides the graphical presentation of the data collected from the sensors; including temperature, wind speed, wind direction, moisture, and leaf wetness. The graphical interface, bar charts, and line charts with trace ball for collected data have been designed and implemented. The embedded database performance and project performance have been investigated and analysed. The performances of Perst Lite and RMS are evaluated in terms of the insert, sequence search, and random search functions based on simulation and real devices. The record numbers vary from 1,000 to 20,000. The project performance contains data receiving and storage, and data presentation and configuration. The performance of data storage and configuration can be negated due to the running mode and the response time. Thus, data presenting performance is the key focus in this project. This performance was divided into the categories of initial, data search, data selection, and charting. The initial performance includes the initialisation of the project parameters, and the reaching of the welcome interface. Data search performance refers to the retrieval of the specified data from the embedded database, measured on 48 data points, which only can be presented on the mobile screen from the retrieved data. These four performance types are measured in thousands of record numbers, varying from 1,000 to 18,000 record numbers, with the retrieved data range varying from 1 day to 30 days.

In the past decade and more than any time before, new technologies have been broadly applied in various fields of interaction between human and machine. Despite many functionality studies, yet, how such technologies should be evaluated within the context of human computer interaction research remains unclear. This research aims at proposing a mechanism to evaluate/predict the design of user interfaces with their interacting components. At the first level of analysis, an original concept extracts the usability results of components, such as effectiveness, efficiency, adjusted satisfaction, and overall acceptability, for comparison in the fields of interest. At the second level of analysis, another original concept defines new metrics based on the level of complexity in interactions between input modality and feedback of performing a task, in the field of classical solid mechanics. Having these results, a set of hypotheses is provided to test if some common satisfaction criteria can be predicted from their correlations with the components of performance, complexity, and overall acceptability. In the context of this research, three multimodal applications are implemented and experimentally tested to study the quality of interactions through the proposed hypotheses: a) full-body gestures vs. mouse/keyboard, in a Box game; b) arm/hand gestures vs. three-dimensional haptic controller, in a Slingshot game; and c) hand/finger gestures vs. mouse/keyboard, in a Race game. Their graphical user interfaces are designed to cover some extents of static/dynamic gestures, pulse/continuous touch-based controls, and discrete/analog tasks measured. They are quantified based on a new definition termed index of complexity which represents a concept of effort in the domain of locomotion interaction. Single/compound devices are also defined and studied to evaluate the effect of user’s attention in multi-tasking interactions. The proposed method of investigation for usability is meant to assist human-computer interface developers to reach a proper overall acceptability, performance, and effort-based analyses prior to their final user interface design.

[pt] A dissertação realiza um estudo ergonômico da interface de produtos Web (sites) focados na transmissão de alta velocidade, considerando as principais barreiras e dificuldades vivênciadas pelos usuários deste tipo de conexão durante a sua interação com o conteúdo de cunho proprietário (plugins). O estudo tem como hipótese: o excesso de plugins (recursos não próprios dos navegadores) nestas interfaces limitam o acesso as páginas com conteúdo Banda Larga e frustam os usuários quanto a carga e a qualidade que os arquivos de vídeo e áudio destes sites deveriam ter. A pesquisa cita os principais acontecimentos, pesquisadores e personalidades que possibilitaram a criação da hipermídia atual, apresentando a história do computador, do CD-ROM, da Internet, da hipermídia e do hipertexto. Este referêncial teórico tem como objetivo auxiliar a compreensão das tecnologias que permitiram o surgimento da Internet Rápida ou Banda Larga. Na primeira parte da pesquisa descrevem-se, ainda, os conceitos de hipertexto, hipermídia e multimídia. Em seguida se estabelece um paralelo entre estas definições e a contextualização com as grades dos sites com conteúdo Banda Larga e os plugins presentes nos arquivos de conteúdo destas páginas. O estudo apontou duas estruturas características dos sites multimídias focados na transmissão rápida: - as páginas hipermídia de cunho hipertextual; - as páginas hipermídia multimídia. A segunda parte da dissertação apresenta o delineamento da pesquisa e os métodos, técnicas e procedimentos da pesquisa utilizados no estudo (questionários com usuários de Internet Banda Larga, Focus Group e Avaliação Cooperativa). Os testes realizados na pesquisa tinham como objetivo: colher opiniões, conhecer hábitos, descobrir dados sob a população usuária e, por fim, observar os colaboradores interagindo com sites reais com conteúdo Banda Larga em tarefas representativas. Estas tarefas permitiram visualizar as principais dificuldades dos usuários com relação ao acesso e ou consumo dos arquivos dinâmicos proprietários. Por fim, as conclusões obtidas com as análises dos resultados dos métodos, técnicas e procedimentos da pesquisa apontam algumas recomendações de projeto de sites multimídia focados na transmissão de alta velocidade. Consideram-se: a utilização dos plugins; a personalização dos sites; e a apresentação do conteúdo sob a ótica do usuário. Deste modo, objetiva-se minimizar os seus constrangimentos e barreiras durante a sua interação com estas interfaces e sistemas. / [en] This will be an ergonomic study of web product interface (sites), focused on high speed transmission. It assesses the main barriers and difficulties experienced by the users of this type of connection during their interaction with proprietary files (plug- ins). The hypothesis of this study is that excess of plug-ins (no self resources) in these interfaces limits the access to broad band web pages, frustrating users as regards the load and quality expected from the audio and video archives. This research discusses the main stylized facts and the research that has made the present hypermedia possible. Furthermore, it presents a brief history of the computer, CD-ROM, Internet, hypermedia and hypertext. This theoretical reference aims at helping to understand the facts that led to the origins of the Broad Band or Speed Internet, and therefore presents the main technologies used for the Broad Band connection. The first part of this paper discusses the definitions of hypertext, hypermedia and multimedia. Then it establishes an analogy between such definitions and contextualization and the Broad Band site grids and plug-ins found in the archives of such web pages. The study points to two structures which are typical of speed transmission multimedia sites: - Hypermedia pages with hypertext characteristics; - Multimedia hypermedia pages. The second part of the paper discusses the methods, techniques and procedures used in the research (questionnaires with Broad Band Internet users, Focus Group and Cooperative Evaluation) as well as the research outlines. The tests performed aim at collecting data/opinions and knowing the habits of the user population, and also observing the interaction between the collaborators and real Broad Band web sites in relevant tasks. Such tasks have made it possible to visualize the main shortcomings of the users towards the access and consumption of proprietary dynamic files. Finally, the findings achieved through the results analysis of research methods, techniques and procedures lead to some multimedia sites project recommendations focused on high speed transmission. These consider using plugins, sites customization and presenting the contents from the users point of view, targeting the reduction of any constraints or barriers they may experience during their interaction with interfaces and systems.

Ma thèse s'inscrit dans le domaine de l'ingénierie de l'interaction homme-machine. Elle traite de la conception d'interfaces hommes machine (IHM). La créativité n'y est souvent considérée que de manière marginale. Pourtant l'effervescence technologique et la diversité résultante des contextes d'usage appellent à de plus en plus de créativité. Ma thèse soutient le principe que l'innovation passe par l'application de processus créatifs. Dès lors, le défi est de savoir explorer largement et efficacement l'espace de conception dès les phases amont du processus. Il convient donc d'intégrer et d'enseigner la créativité dans les processus de conception d'IHM, en particulier pour les concepteurs débutants.Ce positionnement sur le sujet provient d'une double approche : d'une part théorique, avec un état de l'art explorant les dimensions de la créativité et les outils informatiques de support à la créativité ; d'autre part empirique, avec quatre mises en pratique de la créativité dans des domaines de conception différents comme l'architecture, la conception de produit et la conception de systèmes interactifs. Je construis ma contribution sur les principes suivants : (1) la créativité n'est pas réservée à une élite, mais peut être travaillée et renforcée par des outils informatiques ; (2) ces outils doivent soutenir la motivation, la recherche d'inspiration, l'exploration en largeur, et les connaissances relatives au domaine et aux processus de conception. Selon une démarche réflexive, j'applique ces mêmes principes dans ma thèse. Je propose une exploration en largeur du support à la créativité via cinq contributions logicielles complémentaires : Maestro et Bank pour la capitalisation des connaissances ; WebGallery, BrianStorming et Magellan pour l'inspiration et l'exploration de l'espace de conception. Plus précisément, Maestro traite de la capitalisation des processus de conception tandis que BANK assure la structuration et la capitalisation des connaissances en IHM via un graphe de modèles. WebGallery est une galerie de sites web pour inspirer les concepteurs : je conduis une expérimentation sur la perception humaine du style d'un site web. BrianStorming est un assistant au brainstorming : il fournit des suggestions pendant une séance de brainstorming électronique. Magellan est un environnement interactif à base d'algorithmes génétiques qui génèrent et transforment automatiquement des IHM pour un problème de conception donné. Par ce positionnement et ces contributions logicielles, l'ordinateur change de statut : de simple outil, il devient un concepteur assistant, partenaire du processus de créativité. / My PhD thesis contributes to the engineering of Human Computer Interaction (HCI). It deals with the design of User Interfaces (UI). I claim that creative processes should be better considered, and supported by tools especially for novice designers. The challenge is to speed up the exploration of the design space at the early stages of the process. This claim is grounded in both a theoretical state of the art in creativity and creativity support tools, and in practice of the topic with four hands-on experiences of creativity in different areas of design such as architecture, product design and UI design. I build my contribution on the following principles: (1) creativity is not reserved for the elite, but can be tailored and fostered by software tools; (2) the tools must leverage motivation, inspiration, wide exploration, and knowledge in UI and design processes. Through a reflective process, I apply these principles to my thesis. I explore a wide range of creativity support tools through five complementary software contributions: Maestro and Bank for supporting knowledge capitalization; WebGallery, BrianStorming and Magellan for fostering inspiration and exploration of the design space. Maestro addresses the capitalization of design processes whilst BANK gathers knowledge in HCI as a graph of models. WebGallery is a gallery of websites to inspire designers: I report an experiment on human perception of websites styles. BrianStorming is a brainstorming assistant: it provides suggestions in a electronic brainstorming session. Magellan is an interactive environment based on genetic algorithms that automatically generate and transform UIs for a given design problem. This changes the role of the computer: from a simple tool, it becomes a designer's partner in the creative process.

Made available in DSpace on 2014-06-11T19:24:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-10-27Bitstream added on 2014-06-13T20:31:09Z : No. of bitstreams: 1 thomaz_dap_me_bauru.pdf: 4396945 bytes, checksum: bc7aa023a12bcf3e2f968380bc87dea8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este estudo trata das questões relacionadas ao design de interface, usabilidade e técnicas de avaliação de interfaces web. A abordagem teórica inicia-se com o questionamento sobre a popularização dos computadores pessoais e a difusão da internet e seus novos processos communicacionais que fizeram emergir apontamentos sobre a forma de interação entre o ser humano e os sistemas comunicacionais. Também aborda os aspectos de design de interface, ao entender que este corresponde ao primeiro contado do indivíduo com a informação apresentada no site e, por essa razão, ressaltam-se as questões relacionadas à apresentação da informação visual. Para completar a relação entre tecnologia e ser humano, são apresentados dados sobre Interação Humano-Computador (HC), usabilidade e ergonomia cognitiva, e métodos de avaliação de interface, assim como também algumas definições e classificações sobre o jornal impresso e o digital. Deste modo, o estudo apresenta um análise ergonômica e de usabilidade sobre a leitura dos jornais eletrônicos a partir da comparação com os jornais impressos. Como método, adotou-se uma avaliação de percepção do usuário, a partir de um questionário impresso aplicado a um grupo de 41 sujeitos. De modo geral, os resultados indicam que nos jornais analisados há a necessidade de um maior cuidado com os aspectos da representação visual. Neste sentido, entende-se que a pesquisa colaborou com os estudos da área, pois enfatiza a necessidade de se incluir os usuários no desenvolvimento de interfaces web, assim como também em utilizar com maior critério a muldisciplinariedade do suporte e fazer com as áreas de design, usabilidade, ergonomia, tecnologia e comunicação trabalhem em congruência. / The study deals with issues related to interface design, usability and technical evaluation of web interfaces. The theorical approach starts with the questioning of the popularity growth of personal computers and the spread of the Internet with its new communication processes that have emerge notes about the form of interaction between humans and communicational systems. Also covers aspects of interface design, understanding that this is the first contact of the individual with the information presented on the site and, for that reason, issues related to the presentation of visual information are emphasized. To complete the relation between technology and the human being, it presents data about Human-Computer Interaction (HCI), usability and cognitive ergonomics, and methods for interface evaluation, as well as some definitions and classifications on the paper and digital form of the news. Thus, the study presents an ergonomic and usability analysis on the reading of eletronic journal from the comparison with the printed newspaper. As a method, it was adopted an evaluation of the user perception, from a printed questionnaire applied to a group of 41 subjects. Overall, the results indicate that on the analyzed newspaper there is a need for greater care concerning the aspects of visual representation. In this sense, the study helped with the studies in the area, as it emphasizes the need to include users in development process of web interfaces, as well as to use with more discretion the support's multidisciplinarity and make the areas of design, usability, ergonomics, technology and communication to work in congruence.

Orientador: Luis Carlos Paschoarelli / Banca: Nelyse Apparecida Melro Salzedas / Banca: José Carlos Plácido da Silva / Resumo: Este estudo trata das questões relacionadas ao design de interface, usabilidade e técnicas de avaliação de interfaces web. A abordagem teórica inicia-se com o questionamento sobre a popularização dos computadores pessoais e a difusão da internet e seus "novos" processos communicacionais que fizeram emergir apontamentos sobre a forma de interação entre o ser humano e os sistemas comunicacionais. Também aborda os aspectos de design de interface, ao entender que este corresponde ao primeiro contado do indivíduo com a informação apresentada no site e, por essa razão, ressaltam-se as questões relacionadas à apresentação da informação visual. Para completar a relação entre tecnologia e ser humano, são apresentados dados sobre Interação Humano-Computador (HC), usabilidade e ergonomia cognitiva, e métodos de avaliação de interface, assim como também algumas definições e classificações sobre o jornal impresso e o digital. Deste modo, o estudo apresenta um análise ergonômica e de usabilidade sobre a leitura dos jornais eletrônicos a partir da comparação com os jornais impressos. Como método, adotou-se uma avaliação de percepção do usuário, a partir de um questionário impresso aplicado a um grupo de 41 sujeitos. De modo geral, os resultados indicam que nos jornais analisados há a necessidade de um maior cuidado com os aspectos da representação visual. Neste sentido, entende-se que a pesquisa colaborou com os estudos da área, pois enfatiza a necessidade de se incluir os usuários no desenvolvimento de interfaces web, assim como também em utilizar com maior critério a muldisciplinariedade do suporte e fazer com as áreas de design, usabilidade, ergonomia, tecnologia e comunicação trabalhem em congruência. / Abstract: The study deals with issues related to interface design, usability and technical evaluation of web interfaces. The theorical approach starts with the questioning of the popularity growth of personal computers and the spread of the Internet with its "new" communication processes that have emerge notes about the form of interaction between humans and communicational systems. Also covers aspects of interface design, understanding that this is the first contact of the individual with the information presented on the site and, for that reason, issues related to the presentation of visual information are emphasized. To complete the relation between technology and the human being, it presents data about Human-Computer Interaction (HCI), usability and cognitive ergonomics, and methods for interface evaluation, as well as some definitions and classifications on the paper and digital form of the news. Thus, the study presents an ergonomic and usability analysis on the reading of eletronic journal from the comparison with the printed newspaper. As a method, it was adopted an evaluation of the user perception, from a printed questionnaire applied to a group of 41 subjects. Overall, the results indicate that on the analyzed newspaper there is a need for greater care concerning the aspects of visual representation. In this sense, the study helped with the studies in the area, as it emphasizes the need to include users in development process of web interfaces, as well as to use with more discretion the support's multidisciplinarity and make the areas of design, usability, ergonomics, technology and communication to work in congruence. / Mestre

The phenomenon of mental models has long been studied in both cognitive science and HCI, yet their impact in knowledge transfer between user interfaces are not as commonly studied. Rarely are practical examples of this phenomenon studied from an academic perspective. Using a real world example, Skatteverket’s (Swedish tax authorities) information system Basregister, this case study seeks to explore the role of mental models in knowledge transfer between user interfaces. Method of investigation entailed utilizing two design iterations, three interview phases, and five participants employed at Skatteverket. This study investigated if, and how much design elements from well-known external- and the original- system impact the acquisition of new mental models for the newly produced user interface designs. Main results conclude that both external and internal design elements may be to tremendous benefit when the goal is to design with maximum knowledge transfer, as to reduce cognitive load on the user. However, that such implementations should be carefully instigated when designing new UI, and always from a user-centric approach.

The purpose of this thesis was to integrate cognitive science into an existing organization of software systems development, and to display the benefits and importance of applying the theory and methodology of this interdisciplinary field onto this type of research. This was to be accomplished through participating in a project at ISD Datasystem AB, with the objective to investigate and develop new principles of man - machine interaction for fighter control, and build an appropriate workstation prototype. The participation spanned across the first iteration of the project’s development cycle, specified in accordance to the Rational Unified Process. A field study was conducted and several LoFi-prototypes of the graphical and physical man - machine interface (MMI) were made, as well as an evaluation of the developed prototype. The evaluation was performed with the help of end-users, who valuated the prototype in an inquiry and an interview after having performed a scenario interacting with it. The results showed that the prototype’s usability was highly valuated by the users.Data collected during the evaluation could also be used to guide further development of the prototype. The theoretical research and the empirical work in the project both showed that cognitive science is a valuable, and perhaps, an indispensable asset to software systems development, and that the knowledge and tools of cognitive science can be used in order to develop computer systems that are to be integrated in distributed man -machine systems of high complexity.

Do ponto de vista do usuário, a interface é uma das partes mais importantes dos sistemas computacionais, porque por meio dela o usuário vê, ouve e sente. Essa relevância motiva pesquisadores da área de Interação Humano-Computador a estudarem maneiras de se criarem interfaces com design focado em usabilidade. A avaliação da usabilidade de interfaces visa verificar se elas atendem aos requisitos do usuário de forma que as funcionalidades do sistema sejam realizadas de modo efetivo, eficiente e que satisfaça as expectativas do usuário. Tendo em vista que o ciclo de desenvolvimento de software costuma ser longo, avaliações da usabilidade de diferentes versões de interfaces devem ser realizadas no decorrer do processo, como forma de minimizar erros e reduzir custos de produção do sistema. Uma das avaliações de usabilidade mais conhecidas é a avaliação heurística, criada por Jacob Nielsen, que se destaca pelo baixo custo e rapidez de aplicação. Nela, especialistas avaliam as interfaces e os diálogos do sistema com base em um conjunto de regras gerais, as heurísticas, que lhes permitem identificar problemas de usabilidade. Apesar de respeitadas e amplamente usadas, as heurísticas de Nielsen foram criadas sem foco em interfaces de dispositivos móveis, muito difundidos atualmente. Por meio deste trabalho, verificou-se que as heurísticas de Nielsen têm limitações para encontrarem problemas de usabilidade em interfaces de dispositivos móveis. Por conta disso, propôs-se um conjunto de heurísticas para avaliação de interfaces de dispositivos móveis e se definiu um conjunto de diretrizes para o desenvolvimento dessas interfaces. A validação das heurísticas propostas indicou que elas foram mais efetivas que as de Nielsen para encontrarem problemas de usabilidade considerados pelos especialistas como catastróficos ou de baixa gravidade / From the users point of view, the interface is one the most important part of computer systems, because everything he sees, hears and feels are contained therein. This relevance motivates researchers of Human-Computer Interaction to study ways to create interfaces with design focused on usability. The usability evaluation of interfaces aims to determine whether the interfaces meet the requirements of the system so that its functionalities are carried out effectively, efficiently and satisfying the users expectations. Considering that the software development lifecycle is often long, usability evaluations of different versions of interfaces should be made during the process, in order to minimize errors and reduce production costs of the final system. Heuristic evaluation, created by Jacob Nielsen, is one of the most used usability evaluation methods, because of it low cost and ease of implementation. In this evaluation method, experts evaluate interfaces and systems dialogues based on a set of general rules, called heuristics, which enable them to identify usability problems. Although respected and widely used, Nielsens heuristics were not created having mobile devices interfaces in mind. Through this work, it was verified that Nielsens heuristics have limitations in finding usability problems in mobile devices interfaces. Because of this, we proposed a set of heuristics for evaluating interfaces for mobile devices and defined a set of guidelines for the development of these interfaces. The validation of the proposed heuristics indicated that they were more effective than Nielsens to find usability problems considered by experts as catastrophic or of low gravity

Este estudo buscou identificar variáveis e parâmetros determinantes para a otimização do design da interface dos teclados virtuais de padrão Qwerty no contexto da produção de textos em português. Tendo como fonte principal de dados o usuário final, buscou-se, nesta pesquisa, entender de que maneira os variados sistemas de teclado e as diversas configurações possíveis se adequam aos hábitos e à cultura de uso dos diferentes usuários, considerando-se, neste ponto, as diferenças entre a língua inglesa (condicionante do arranjo Qwerty) e a portuguesa. A pesquisa foi composta de dois experimentos e um questionário e conduzida junto a usuários de dispositivos móveis com telas de 3,5 a seis polegadas, limites que englobam grande parte dos aparelhos equipados com os teclados aqui analisados. No capítulo 1 contextualizou-se o problema estudado e definiu-se espectro da pesquisa. O capítulo 2 apresenta a revisão bibliográfica sobre o tema e trata do uso do teclado desde seu surgimento até sua utilização em smartphones, das especificidades da língua portuguesa e de caminhos, métodos e soluções encontrados em pesquisas correlatas. No capítulo 3 são apresentados os métodos utilizados em cada etapa do estudo: o questionário buscou respostas junto a 302 usuários a respeito de diversos fatores ligados à utilização do teclado virtual em smartphones; os dois experimentos envolveram a gravação em vídeo da interação de 17 participantes com o teclado em diferentes tarefas de inserção de textos em português, o primeiro envolvendo a cópia de textos pré-definidos em diferentes configurações de teclado, e o segundo a análise da produção de textos livres no aparelho do próprio participante, configurado conforme suas preferências pessoais. O capítulo 4 apresenta as análises empreendidas em cada etapa de interação com usuários e o capítulo 5 mostra as conclusões a que se chegou com base nos dados analisados. Os resultados mostraram que em grande parte dos aparelhos o desenho do teclado é pautado pelo arranjo Qwerty, que delimita o tamanho e mapeamento das teclas mais utilizadas para inserção de textos. Observou-se também que os usuários que utilizam seus aparelhos com maior versatilidade têm maior fluência no uso do teclado e acabam por contornar as limitações da interface, vindo a avaliar melhor o sistema. O uso eficiente do teclado estaria ligado não especificamente à velocidade de digitação, mas a um ritmo próprio de cada indivíduo que, quando alterado, contribui para a incidência de erros. Nesse sentido, verificou-se que as tarefas de cópia, por envolver a observação constante do texto a ser reproduzido, tendem a causar pausas no processo de digitação, aumentando a probabilidade da ocorrência de toques em teclas diferentes das pretendidas. Erros deste tipo, mais comuns, mostraram-se estar atrelados à maior utilização das teclas e parecem ser, portanto, inevitáveis. O processo de prevenção e correção de falhas de digitação, desta forma, mostrou-se fator fundamental na utilização deste tipo de teclado, evidenciando a importância dos assistentes de digitação. Estes, no entanto, podem vir a condicionar a maneira como o usuário interage com o teclado e, em alguns casos, contribuir para a ocorrência de erros. / This study seeks to identify, in the context of Portuguese text entry, determinant variables and parameters for the Qwerty keyboard interface design optimization. Considering that the primary data source is the final user, this research attempts to understand how adequate are the various keyboard systems and configurations to users\' habits and culture, taking into account the differences between English (language used to define the Qwerty layout) and Portuguese. In this research, two experiments and one survey were carried out with 3,5\" to 6\" smartphones users, boundaries that encompasses the majority of the devices equipped with the keyboard types targeted to be analyzed. In the first chapter the problem was contextualized and the spectrum of the research was defined. The second chapter presents the history of the Qwerty keyboard, since its development (when the typewriters were being created) to the use in smartphones, shows important singularities of Portuguese language and an overview of related studies. In the third chapter the methods applied in this research were shown: the survey was carried out with 302 participants to find how they cope with different aspects of the use of smartphones; the two experiments involved the recording of 17 users interacting with the keyboard in different kinds of tasks, text transcription with varying device configuration and free text production in the participant\'s own device. The fourth chapter presents the analysis of the data obtained in the different stages of the study that involved interaction with users and the fifth chapter shows the conclusions made base on the data analyzed. Results showed that great part of the devices present the keyboard ruled by the Qwerty layout, which limits the size and the mapping of the keys most used for text insertion. It was also noted that those who use their devices with greater flexibility are more fluent in the use of the keyboard and create shortcuts to cope with limitations imposed by this interface. These users tend to give the keyboard a better evaluation. The results also showed that a efficient use of the interface would not be tied specifically to typing speed, but rather to the individual typing rhythm that, when disturbed, contributes for the occurrence of errors. In this sense, it was noted that copy tasks, because it involves constant monitoring of the text to be copied, tend to produce pauses in the typing process, which increases the probability of touches landing in different keys than intended. This type of error, most common, appeared to be tied to key usage and, thus, seem to be inevitable. Error preventing and correction, this way, are fundamental for the usage of virtual keyboards in small devices. Results showed that the use of typing assistants, however, could modify the way users type and, in some cases, contribute to the increase of error occurrence.