Dissertations / Theses on the topic 'Human-computer interaction'

Sustainability is a growing concern in a world where climate change threatens to inflict massive environmental and human damage in the coming decades. As climate change becomes a global issue, researchers and professionals from many pursuits are beginning to rally around the cause of bringing about an economically and environmentally sustainable future. Computer science and the related fields of human-computer interaction and interaction design have both a moral obligation and profound opportunity to contribute to environmental sustainability. In this thesis, I will examine the efforts of computer scientists and interaction designers in sustainability so far in order to form an understanding of what computer science has contributed to the effort of curbing damage to the environment to date. While the contributions of computer science and related fields to sustainability are significant, there are many ways in which they are deficient. Therefore, I will look to the future possibilities for academic and industrial developments and improvements in sustainable technology from the perspective of computer scientists and practitioners of related disciplines, and make recommendations as to the direction these fields should take in order to best serve the global thrust toward a sustainable human civilization.

Along with the rapid development of intelligent information age, users are having a growing interaction with smart devices. Such smart devices are interconnected together in the Internet of Things (IoT). The sensors of IoT devices collect information about users' behaviors from the interaction between users and devices. Since users interact with IoT smart devices for the daily communication and social network activities, such interaction generates a huge amount of network traffic. Hence, users' behaviors are playing an important role in the security of IoT smart devices, and the security aspects of Human-Computer Interaction are becoming significant. In this dissertation, we provide a threefold contribution: (1) we review security challenges of HCI-based authentication, and design a tool to detect deceitful users via keystroke dynamics; (2) we present the impact of users' behaviors on network traffic, and propose a framework to manage such network traffic; (3) we illustrate a proposal for energy-constrained IoT smart devices to be resilient against energy attack and efficient in network communication. More in detail, in the first part of this thesis, we investigate how users' behaviors impact on the way they interact with a device. Then we review the work related to security challenges of HCI-based authentication on smartphones, and Brain-Computer Interfaces (BCI). Moreover, we design a tool to assess the truthfulness of the information that users input using a computer keyboard. This tool is based on keystroke dynamics and it relies on machine learning technique to achieve this goal. To the best of our knowledge, this is the first work that associates the typing users' behaviors with the production of deceptive personal information. We reached an overall accuracy of 76% in the classification of a single answer as truthful or deceptive. In the second part of this thesis, we review the analysis of network traffic, especially related to the interaction between mobile devices and users. Since the interaction generates a huge amount of network traffic, we propose an innovative framework, GolfEngine, to manage and control the impact of users behavior on the network relying on Software Defined Networking (SDN) techniques. GolfEngine provides users a tool to build their security applications and offers Graphical User Interface (GUI) for managing and monitoring the network. In particular, GolfEngine provides the function of checking policy conflicts when users design security applications and the mechanism to check data storage redundancy. GolfEngine not only prevents the malicious inputting policies but also it enforces the security about network management of network traffic. The results of our simulation underline that GolfEngine provides an efficient, secure, and robust performance for managing network traffic via SDN. In the third and last part of this dissertation, we analyze the security aspects of battery-equipped IoT devices from the energy consumption perspective. Although most of the energy consumption of IoT devices is due to user interaction, there is still a significant amount of energy consumed by point-to-point communication and IoT network management. In this scenario, an adversary may hijack an IoT device and conduct a Denial of Service attack (DoS) that aims to run out batteries of other devices. Therefore, we propose EnergIoT, a novel method based on energetic policies that prevent such attacks and, at the same time, optimizes the communication between users and IoT devices, and extends the lifetime of the network. EnergIoT relies on a hierarchical clustering approach, based on different duty cycle ratios, to maximize network lifetime of energy-constrained smart devices. The results show that EnergIoT enhances the security and improves the network lifetime by 32%, compared to the earlier used approach, without sacrificing the network performance (i.e., end-to-end delay).<br>Insieme al rapido sviluppo dell'era dell'informazione, gli utenti stanno avendo una crescente interazione con i dispositivi intelligenti. Tali dispositivi intelligenti sono interconnessi tra loro nell'Internet of Things (IoT). I sensori dei dispositivi IoT raccolgono informazioni sui comportamenti degli utenti dall'interazione tra utenti e dispositivi. Poiché gli utenti interagiscono con i dispositivi intelligenti IoT per le attività quotidiane di comunicazione e social network, tale interazione genera un'enorme quantità di traffico di rete. Quindi, i comportamenti degli utenti stanno giocando un ruolo importante nella sicurezza dei dispositivi intelligenti IoT e gli aspetti di sicurezza dell'interazione uomo-macchina stanno diventando significativi. In questa tesi, forniamo un triplice contributo: (1) esaminiamo le sfide alla sicurezza dell'autenticazione basata su HCI e progettiamo uno strumento per rilevare utenti ingannevoli tramite la dinamica dei tasti; (2) presentiamo l'impatto dei comportamenti degli utenti sul traffico di rete e proponiamo un framework per gestire tale traffico di rete; (3) illustriamo una proposta per dispositivi intelligenti IoT con vincoli energetici per essere resilienti contro attacchi energetici ed efficienti nella comunicazione di rete. Più in dettaglio, nella prima parte di questa tesi, analizziamo il modo in cui i comportamenti degli utenti influiscono sul modo in cui essi interagiscono con un dispositivo. Quindi, esaminiamo il lavoro relativo alle sfide di sicurezza dell'autenticazione basata su HCI su smartphone e Brain-Computer Interfaces (BCI). Inoltre, progettiamo uno strumento per valutare la veridicità delle informazioni che gli utenti inseriscono usando la tastiera di un computer. Questo strumento si basa sulla dinamica dei tasti e si basa sulla tecnica di apprendimento automatico per raggiungere tale obiettivo. Per quanto siamo a conoscenza, questo è il primo lavoro che associa i comportamenti degli utenti di digitazione alla produzione di informazioni personali ingannevoli. Abbiamo raggiunto un'accuratezza complessiva del 76% nella classificazione di una singola risposta come veritiera o mendace. Nella seconda parte di questa tesi, esaminiamo l'analisi del traffico di rete, in particolare in relazione all'interazione tra dispositivi mobili e utenti. Poiché l'interazione genera un'enorme quantità di traffico di rete, proponiamo un framework innovativo, GolfEngine, per gestire e controllare l'impatto del comportamento degli utenti sulla rete facendo affidamento sulle tecniche di Software Defined Networking (SDN). GolfEngine fornisce agli utenti uno strumento per costruire le loro applicazioni di sicurezza e offre una GUI (Graphical User Interface) per la gestione e il monitoraggio della rete. In particolare, GolfEngine fornisce la funzione di controllare i conflitti di policy quando gli utenti progettano applicazioni di sicurezza e il meccanismo per controllare la ridondanza dell'archiviazione dei dati. GolfEngine non solo previene le politiche di inserimento malizioso, ma impone anche la sicurezza sulla gestione della rete del traffico di rete. I risultati della nostra simulazione sottolineano che GolfEngine fornisce prestazioni efficienti, sicure e robuste per la gestione del traffico di rete tramite SDN. Nella terza e ultima parte di questa tesi, analizziamo gli aspetti di sicurezza dei dispositivi IoT dotati di batteria dal punto di vista del consumo energetico. Sebbene la maggior parte del consumo di energia dei dispositivi IoT sia dovuta all'interazione dell'utente, c'è ancora una quantità significativa di energia consumata dalla comunicazione point-to-point e dalla gestione della rete IoT. In questo scenario, un avversario può compromettere un dispositivo IoT e condurre un attacco Denial of Service (DoS) che punta a esaurire le batterie di altri dispositivi. Pertanto, proponiamo EnergIoT, un nuovo metodo basato su politiche energetiche che prevengono tali attacchi e, allo stesso tempo, ottimizza la comunicazione tra utenti e dispositivi IoT ed estende la durata della rete. EnergIoT si basa su un approccio di clustering gerarchico, basato su diversi rapporti di duty cycle, per massimizzare la durata della rete di dispositivi intelligenti con vincoli energetici. I risultati mostrano che EnergIoT migliora la sicurezza e la durata della rete del 32%, rispetto agli approcci utilizzati in precedenza, senza sacrificare le prestazioni della rete (cioè, ritardo end-to-end).

L'envelliment de la població i la importància de les TIC a la societat actual han motivat la necessitat d'integrar més a les persones grans en la interacció persona-ordinador. La investigació actual es centra en factors individuals de l'envelliment i l'aproximació més generalitzada és dissenyar interfícies considerant les persones grans com a conjunt de factors. Aquesta tesi doctoral planteja un paradigma diferent: de factors a persones grans com a actors. En aquest paradigma, prestar atenció als canvis en capacitats funcionals no és l'únic que importa, cal que interacció i ús real estiguin més fortament relacionats. En aquest marc, aquesta tesi presenta els resultats d'un treball etnogràfic extens sobre el correu electrònic i la web. Mètodes quantitatius i mixtes s'han utilitzat en altres aspectes, que recolzen aquest estudi de camp. Altres capítols presenten contribucions metodològiques en avaluació en entorns reals. La tesi acaba proposant estratègies per a investigar amb persones grans com a actors socials, insistint en considerar l'experiència de vida de la gent gran i estudiar més l'ús i les interaccions en entorns reals combinant etnografia i treball més experimental.<br>El envejecimiento de la población y la importancia de las TIC en la sociedad actual han motivado la necesidad de integrar más a las personas mayores en la interacción persona-ordenador. La investigación actual se centra en factores individuales del envejecimiento y la aproximación más generalizada es diseñar interfaces considerando a las personas mayores como un conjunto de factores. Esta tesis doctoral plantea un paradigma diferente: de factores a personas mayores como actores. En este paradigma, prestar atención a los cambios en capacidades funcionales no es lo único que importa, sino que interacción y uso real deberían estar más fuertemente relacionados. En este marco, esta tesis presenta los resultados de un trabajo etnográfico extenso sobre el correo electrónico y la web. Métodos cuantitativos y mixtos se han utilizado en otros aspectos, que apoyan este estudio de campo. Otros capítulos presentan contribuciones metodológicas en evaluación en entornos reales. La tesis acaba proponiendo estrategias para investigar con personas mayores como actores sociales, insistiendo en considerar la experiencia de vida de la gente mayor y estudiar más el uso y las interacciones en entornos reales combinando etnografía y trabajo más experimental.<br>Population ageing and the role of computers in current society have created a need to strengthen HCI with older people. The current paradigm considers them as a set of factors and central to it is compensation for age-related changes in functional abilities. This dissertation proposes a different paradigm: from factors towards interaction based on older people as social actors. Within this paradigm, compensating for diminishing abilities is not the cornerstone of research. Instead, interaction and real-life use should be closely intertwined. Against this framework, the thesis presents the results of an extensive ethnographic work on e-mail and web use. Quantitative and mixed methods are employed in other aspects related to use and interaction which complement this major study. Other chapters include methodological contributions to real-life evaluation. The dissertation discusses strategies for approaching HCI with older people. Central to them is the concept of life experience and the need to turn to everyday interactions by combining classical ethnography with experimentations.

The purpose of this master's thesis project is to design, implement and evaluate vision-based user interfaces for use in the context of virtual environments. Three interfaces are treated. The first one is a 4 degrees of freedom (DOF) mouse that can track the position and 1 DOF or rotation (roll) of a user's hand. The second one is a 6 DOF mouse that can track both the position and the orientation of a user's hand in 3D space. Finally the third one is a laser pointing interface used to track the laser spot of a standard laser pointer, in order to interact with a large screen display. The two latter interfaces use an auto-calibrated approach based on planar homography, that distinguish them from the standard computer-vision based approach which requires a previous step of calibration.

This thesis initially presents an 'assay' of the literature pertaining to individual differences in human-computer interaction. A series of experiments is then reported, designed to investigate the association between a variety of individual characteristics and various computer task and interface factors. Predictor variables included age, computer expertise, and psychometric tests of spatial visualisation, spatial memory, logical reasoning, associative memory, and verbal ability. These were studied in relation to a variety of computer-based tacks, including: (1) word processing and its component elements; (ii) the location of target words within passages of text; (iii) the navigation of networks and menus; (iv) command generation using menus and command line interfaces; (v) the search and selection of icons and text labels; (vi) information retrieval. A measure of self-report workload was also included in several of these experiments. The main experimental findings included: (i) an interaction between spatial ability and the manipulation of semantic but not spatial interface content; (ii) verbal ability being only predictive of certain task components of word processing; (iii) age differences in word processing and information retrieval speed but not accuracy; (iv) evidence of compensatory strategies being employed by older subjects; (v) evidence of performance strategy differences which disadvantaged high spatial subjects in conditions of low spatial information content; (vi) interactive effects of associative memory, expertise and command strategy; (vii) an association between logical reasoning and word processing but not information retrieval; (viii) an interaction between expertise and cognitive demand; and (ix) a stronger association between cognitive ability and novice performance than expert performance.

The quality attribute concerning usability is generally of significant importance to systems. The area of Human Computer Interaction, HCI, especially handles several usability aspects. This degree project emphasizes HCI in a context of, so called, Smart House. The report is divided into three main sections: theory, application, and measurement results. In the theory section we will present about the context of HCI and the content of HCI, such as HCI model and goals of HCI design. In the application section we discuss the use of mobile phones as a device to remotely control devices of smart houses, and present a system developed to support such services. In order to make the system more attractive, we decided to design it for two categories of operations, menu operation and direct-touch operation mode. Finally, we have used questionnaires for reasons of measuring user satisfaction. Through investigation and analysis of the result of this, we come to the conclusion that system usability is good.

The main objective of the research described in this thesis was to investigate and understand the origins of culturally-determined usability problems in the context of Human Computer Interaction (HCI) to develop a method for treating this issue, when designing systems intended to be shared by culturally-heterogeneous user groups, such as Computer Supported Co-operative Work (CSCW) systems and the Internet. The resulting approach supports HCI designers by providing an alternative to internationalisation and localisation guidelines, which are inappropriate for tackling culturally-determined usability problems in the context of shared-systems. The research also sought to apply and test the developed approach in order to assess its efficacy and to modify or improve it accordingly.

Users’ trust in online situations is influenced by various characteristics of human-computer interaction. Looking at the increasing scope of services online, it remains an up-to-date issue, expanding its meaning for both informational and transactional websites. In this work, the Scale for Online Users’ Trust (SCOUT) was developed to assess the trustworthiness of both types of websites. Based on the scale, the effects of user experience on users’ trust were examined in several studies. For informational websites, hedonic qualities appeared to be significant predictors of trustworthiness in addition to usability. The effects could be confirmed for transactional websites. Furthermore, perceptions of security aspects were investigated in a set of studies. The effects of customer ratings, fictitious graphical elements, web assurance seals and interactive security-related feedback on users’ trust were analyzed. Findings from all together 11 studies of this work allow for inferences for website design that could support academics and practitioners in designing for trustworthy web environments<br>Nutzervertrauen in Websites ist sowohl auf informationalen als auch auf transaktionalen Websites nach wie vor ein entscheidender Faktor für erfolgreiche Online-Situationen. In dieser Arbeit wird die Entwicklung des Fragebogens SCOUT (Scale for Online Users’ Trust) beschrieben, mit dem die Vertrauenswürdigkeit von Websites beider Kategorien gleichermaßen erfasst werden kann. Darauf aufbauend wurde die Wirkung des Nutzererlebens auf Vertrauen in mehreren Studien untersucht. Für informationale Websites ergaben sich hedonische Merkmale und Usability als signifikante Prädiktoren von Vertrauenswürdigkeit. Diese Effekte konnten für transaktionale Websites bestätigt werden. Zusätzliche wurde geprüft, wie Kundenbewertungen, fiktive grafische Elemente, Gütesiegel und interaktive sicherheitsrelevante Rückmeldungen auf Nutzervertrauen wirken. Aus insgesamt elf Studien lassen sich Empfehlungen für eine vertrauensförderliche Website-Gestaltung ableiten

Esta dissertação apresenta um estudo sobre linguagens táteis em interação humanocomputador e uma nova abordagem de prefixação vibrotátil. Nós pretendemos analisar como as escolhas feitas durante o processo de concepção de vocabulários táteis afetam o desempenho do usuário em uma tarefa interativa. Por isso desenvolvemos e testamos diferentes conjuntos de sinais táteis para suporte à navegação em ambientes virtuais. Isso nos levou a esboçar o conceito de Padrão Tátil Modificador para comunicação vibrotátil que foi testado por meio de experimentos com usuários. Na avaliação dos vocabulários táteis construídos com padrões modificadores foram considerados os efeitos de estimulação multisensorial, fatores relacionados ao processamento de seqüências táteis e o mascaramento causado pela exibição de múltiplos estímulos ao mesmo tempo. Resultados mostram que os participantes que usaram vocabulários construídos com padrões modificadores obtiveram desempenho melhor na tarefa de navegação. Esse e outros resultados relacionados à percepção, aprendizagem e interpretação dos nossos vocabulários atestam a validade do uso de modificadores na construção de linguagens táteis. As conclusões extraídas deste trabalho se mostram úteis no auxílio à concepção de interfaces táteis que sejam usáveis e que demandem expressividade de seus vocabulários.<br>This thesis presents a study about tactile languages in human-computer interaction and a novel approach for vibrotactile prefixation. We intended to analyse how the choices made during the design process of tactile vocabularies would affect the user performance on an interactive task. Therefore, we have designed and tested different sets of tactile signals for aid navigation in virtual environments. It leaded us to fashion the concept of Modifier Tactile Pattern for vibrotactile communication which was tested through user experiments. In the assessment of the modifier-based vocabularies we attempted to effects of multisensory stimulation, factors related to the processing of tactile sequences and masking caused by multiple stimuli delivered in a same time. Results show that those participants who used modifier-based vocabularies performed better the navigation task. That and others results related to perception, learning and interpretation of our tactile vocabularies show the validity of the use of modifiers on tactile languages. The statements made from this work will be useful for designing usable tactile interfaces that demand expressive vocabularies.

This master's thesis deals with problems of testing, especially manual and beta testing. Further thesis discuss area of Human - Computer Interaction and looks for possibilities of effective managing of HCI projects. As solution project hosting area is proposed, explained and existing solutions are examined. In practical part of thesis system for managing HCI projects is designed and implemented based on previous research.

Cuando las personas interactúan con los ordenadores, hay mucha información que no se proporciona a propósito. Mediante el estudio de estas interacciones implícitas es posible entender qué características de la interfaz de usuario son beneficiosas (o no), derivando así en implicaciones para el diseño de futuros sistemas interactivos. La principal ventaja de aprovechar datos implícitos del usuario en aplicaciones informáticas es que cualquier interacción con el sistema puede contribuir a mejorar su utilidad. Además, dichos datos eliminan el coste de tener que interrumpir al usuario para que envíe información explícitamente sobre un tema que en principio no tiene por qué guardar relación con la intención de utilizar el sistema. Por el contrario, en ocasiones las interacciones implícitas no proporcionan datos claros y concretos. Por ello, hay que prestar especial atención a la manera de gestionar esta fuente de información. El propósito de esta investigación es doble: 1) aplicar una nueva visión tanto al diseño como al desarrollo de aplicaciones que puedan reaccionar consecuentemente a las interacciones implícitas del usuario, y 2) proporcionar una serie de metodologías para la evaluación de dichos sistemas interactivos. Cinco escenarios sirven para ilustrar la viabilidad y la adecuación del marco de trabajo de la tesis. Resultados empíricos con usuarios reales demuestran que aprovechar la interacción implícita es un medio tanto adecuado como conveniente para mejorar de múltiples maneras los sistemas interactivos.<br>Leiva Torres, LA. (2012). Diverse Contributions to Implicit Human-Computer Interaction [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17803<br>Palancia

The work is devoted to Human-computer interaction and its main goal is to get closer to the field. The first part describes two main areas, namely Cognitive Science and Cogni-tive Psychology, from which HCI is based on. The second part deals specifically with Human-computer interaction, the history of the origins, aspects of human factor, ele-ments of interaction and modeling of interaction together with examples from everyday life.

This thesis describes the development and evaluation of a theoretical framework to account for the dynamic aspects of behaviour at the Human-Computer Interface (HCIF). The purpose behind this work is to allow for the consideration of dynamic Human-Computer Interaction (HCI) in the design of interactive computer systems, and to facilitate the generation of design tools for this purpose. The work describes an example of a design tool which demonstrates how designers of interactive computer systems may account for some aspects of the dynamics of behaviour, involved with the use of computers, in the design of new interactive systems. The thesis offers empirical and literary evidence to support the validity of the dynamic factors governing the interaction of humans with computers.

One of the main goals of Human Computer Interaction (HCI) is to improve the interface between users and computers: interfacing should be effortless and easy to learn. In this thesis, we pursue this goal, aiming to reduce the stress of users and increase their wellbeing. We work on two different but complementary approaches: (i) Automatic assessment of user’s inner psychological state, so as to enhance computer-human interaction; and (ii) Information presentation in a comprehensive manner, with no stress added by devices and applications when delivering information. Not only computers should understand their users, but also users should easily understand the information given by computers. For the first approach we collected physiological and psychological data from people exposed to emotional stimuli. We created a database, and made it freely available to the community, for further use in research on automated detection of the differences in the inner states of users. We employed the data for predicting both the emotional state of users and their personality traits. For the second approach, we investigated two devices that intend to provide comprehensible feedback easily. First we discuss how to utilize a breathing sensor that informs its users on their current physiological state and on how to decrease the stress in daily life by adapting their breathing patterns. Here we investigated general criteria on how to develop systems that are easily understandable. The second device was a tactile belt. We analyze the belt as a solution that provides comprehensive guidance information in navigation contexts, and that does not require cognitive effort. The belt uses localized tactile stimulation to transmit directional information. By employing the tactile sense it can augment or even replace the information normally received through eyes and ears. Finally, we discuss opportunities for future applications of our research, and conclude with a summary of our contributions to HCI: transmitting information from humans to machines and vice versa.

One of the main goals of Human Computer Interaction (HCI) is to improve the interface between users and computers: interfacing should be effortless and easy to learn. In this thesis, we pursue this goal, aiming to reduce the stress of users and increase their wellbeing. We work on two different but complementary approaches: (i) Automatic assessment of user’s inner psychological state, so as to enhance computer-human interaction; and (ii) Information presentation in a comprehensive manner, with no stress added by devices and applications when delivering information. Not only computers should understand their users, but also users should easily understand the information given by computers. For the first approach we collected physiological and psychological data from people exposed to emotional stimuli. We created a database, and made it freely available to the community, for further use in research on automated detection of the differences in the inner states of users. We employed the data for predicting both the emotional state of users and their personality traits. For the second approach, we investigated two devices that intend to provide comprehensible feedback easily. First we discuss how to utilize a breathing sensor that informs its users on their current physiological state and on how to decrease the stress in daily life by adapting their breathing patterns. Here we investigated general criteria on how to develop systems that are easily understandable. The second device was a tactile belt. We analyze the belt as a solution that provides comprehensive guidance information in navigation contexts, and that does not require cognitive effort. The belt uses localized tactile stimulation to transmit directional information. By employing the tactile sense it can augment or even replace the information normally received through eyes and ears. Finally, we discuss opportunities for future applications of our research, and conclude with a summary of our contributions to HCI: transmitting information from humans to machines and vice versa.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>A Visão Computacional pode ser utilizada para capturar gestos e criar dispositivos de interação com computadores mais intuitivos e rápidos. Os dispositivos comerciais atuais de interação baseados em gestos utilizam equipamentos caros (dispositivos de seguimento, luvas, câmeras especiais, etc.) e ambientes especiais que dificultam a difusão para o público em geral. Este trabalho apresenta um estudo sobre a viabilidade de utilizarmos câmeras Web como dispositivo de interação baseado em gestos da Mão. Em nosso estudo consideramos que a mão humana está limpa, isto é, sem nenhum dispositivo (mecânico, magnético ou óptico) colocado nela. Consideramos ainda que o ambiente onde ocorre a interação tem as características de um ambiente de trabalho normal, ou seja, sem luzes ou panos de fundo especiais. Para avaliar a viabilidade deste mecanismo de interação, desenvolvemos alguns protótipos. Neles os gestos da mão e as posições dos dedos são utilizados para simular algumas funções presentes em mouses e teclados, tais como selecionar estados e objetos e definir direções e posições. Com base nestes protótipos apresentamos algumas conclusões e sugestões para trabalhos futuros.<br>Computer Vision can be used to capture gestures and create more intuitive and faster devices to interact with computers. Current commercial gesture-based interaction devices make use of expensive equipment (tracking devices, gloves, special cameras, etc.) and special environments that make the dissemination of such devices to the general public difficult. This work presents a study on the feasibility of using Web cameras as interaction devices based on hand-gestures. In our study, we consider that the hand is clean, that is, it has no (mechanical, magnetic or optical) device. We also consider that the environment where the interaction takes place has the characteristics of a normal working place, that is, without special lights or backgrounds. In order to evaluate the feasibility of such interaction mechanism, we have developed some prototypes of interaction devices. In these prototypes, hand gestures and the position of fingers were used to simulate some mouse and keyboard functions, such as selecting states and objects, and defining directions and positions. Based on these prototypes, we present some conclusions and suggestions for future works.

By the availability of today&rsquo<br>s inexpensive powerful hardware, it becomes possible to design real-time computer vision systems even in personal computers. Therefore, computer vision becomes a powerful tool for human-computer interaction (HCI). In this study, three different vision-based HCI systems are described. As in all vision-based HCI systems, the developed systems requires a camera (a webcam) to monitor the actions of the users. For pointing tasks, laser pointer is used as the pointing device. The first system is Vision-Based Keyboard System. In this system, the keyboard is a passive device. Therefore, it can be made up of any material having a keyboard layout image. The web camera is placed to see the entire keyboard image and captures the movement of the laser beam. The user enters a character to the computer by covering the corresponding character region in the keyboard layout image with the laser pointer. Additionally, this keyboard system can be easily adapted for disabled people who have little or no control of their hands to use a keyboard. The disabled user can attach a laser pointer to an eyeglass and control the beam of the laser pointer by only moving his/her head. For the same class of disabled people, Vision-Based Mouse System is also developed. By using the same setup used in the previous keyboard system, this system provides the users to control mouse cursor and actions. The last system is Vision-Based Continuous Graffiti1-like Text Entry System. The user sketches characters in a GraffitiTM-like alphabet in a continuous manner on a flat surface using a laser pointer. The beam of the laser pointer is tracked during the image sequences captured by a camera and the corresponding written word is recognized from the extracted trace of the laser beam.

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2006.<br>Includes bibliographical references (p. 113-122).<br>The mobile phone is always carried with the user and is always active: it is a very personal device. It fosters and satisfies a need to be constantly connected to one's significant other, friends or business partners. At the same time, mobile devices are often used in public, where one is surrounded by others not involved in the interaction. This private interaction in public is often a cause of unnecessary disruption and distraction, both for the bystanders and even for the user. Nevertheless, mobile devices do fulfill an important function, informing of important events and urgent communications, so turning them off is often not practical nor possible. This thesis introduces Intimate Interfaces: discreet interfaces that allow subtle private interaction with mobile devices in order to minimize disruption in public and gain social acceptance. Intimate Interfaces are inconspicuous to those around the users, while still allowing them to communicate. The concept is demonstrated through the design, implementation and evaluation of two novel devices: * Intimate Communication Armband - a wearable device, embedded in an armband, that detects motionless gestures through electromyographic (EMG) sensing for subtle input and provides tactile output;<br>(cont.) * Notifying Glasses - a wearable notification display embedded in eyeglasses; it delivers subtle cues to the peripheral field of view of the wearer, while being invisible to others. The cues can convey a few bits of information and can be designed to meet specific levels of visibility and disruption. Experimental results show that both interfaces can be reliably used for subtle input and output. Therefore, Intimate Interfaces can be profitably used to improve mobile human-computer interaction.<br>by Enrico Costanza.<br>S.M.

Die langfristigen Folgen von psychischer Fehlbeanspruchung stellen ein beträchtliches Problem unserer modernen Gesellschaft dar. Zur Identifizierung derartiger Fehlbelastungen während der Mensch-Maschine-Interaktion (MMI) kann die objektive, kontinuierliche Messung der psychischen Beanspruchung einen wesentlichen Beitrag leisten. Neueste Entwicklungen in der Sensortechnologie und der algorithmischen Methodenentwicklung auf Basis von KI liefern die Grundlagen zu ihrer messtechnischen Bestimmung. Vorarbeiten zur Entwicklung einer Methode zur neuronalen Beanspruchungsdiagnostik sind bereits erfolgt (Radüntz, 2017). Eine praxisrelevante Nutzung dieser Ergebnisse ist erfolgsversprechend, wenn die Methode mit Wearables kombiniert werden kann. Gleichzeitig sind die Evaluation und bedingungsbezogene Reliabilitätsprüfung der entwickelten Methode zur neuronalen Beanspruchungsdiagnostik in realitätsnahen Umgebungen erforderlich. Im Rahmen von experimentellen Untersuchungen der Gebrauchstauglichkeit von kommerziellen EEG-Registrierungssystemen für den mobilen Feldeinsatz wird die darauf basierende Systemauswahl für die MMI-Praxis getroffen. Die Untersuchungen zur Validierung der kontinuierlichen Methode zur Beanspruchungsdetektion erfolgt am Beispiel des Fluglotsenarbeitsplatzes beim simulierten „Arrival Management“.<br>The long-term negative consequences of inappropriate mental workload on employee health constitute a serious problem for a digitalized society. Continuous, objective assessment of mental workload can provide an essential contribution to the identification of such improper load. Recent improvements in sensor technology and algorithmic methods for biosignal processing are the basis for the quantitative determination of mental workload. Neuronal workload measurement has the advantage that workload registration is located directly there where human information processing takes place, namely the brain. Preliminary studies for the development of a method for neuronal workload registration by use of the electroencephalogram (EEG) have already been carried out [Rad16, Rad17]. For the field use of these findings, the mental workload assess- ment on the basis of the EEG must be evaluated and its reliability examined with respect to several conditions in realistic environments. A further essential require-ment is that the method can be combined with the innovative technologies of gel free EEG registration and wireless signal transmission. Hence, the presented papers include two investigations. Main subject of the first investigation are experimental studies on the usability of commercially-oriented EEG systems for mobile field use and system selection for the future work. Main subject of the second investigation is the evaluation of the continuous method for neuronal mental workload registration in the field. Thereby, a challenging application was used, namely the arrival management of aircraft. The simulation of the air traffic control environment allows the realisation of realistic conditions with different levels of task load. Furthermore, the work is well contextualized in a domain which is very sensible to human-factors research.

This thesis presents a theoretical framework for the study of interactive systems, using methods from information theory, machine learning and control theory. The framework builds on the information-theoretic capacities of empowerment, relevant information and mutual information, which I adapt and apply to the domain of human-computer interaction. Three user studies exploring dynamic interactive scenarios - one car-tracking and two collaborative target-acquisition experiments - provide empirical data for the development of probabilistic models, used in the characterisation of specific aspects of human performance, such as the level of control, the quality of decision-making, and the level of engagement in interpersonal coordination. Human control models are extended to accommodate for the inherent lags, characteristic for human-computer and human-human interaction, in a principled way. Optimal controllers, describing particular patterns of human behaviour, are built on these theoretical models, providing evidence for specific limits of human performance through simulations. The thesis describes the potential of empowerment, as a generic task-independent measure of control, to characterise the uncertainty in human-machine interfaces. This work builds an important bridge between theory and experiments, and suggests that the proposed information-theoretic concepts could provide analytical tools for supporting the design and evaluation of interactive systems, by elucidating novel aspects of human performance complementing standard measures. The thesis provides proof of concept examples for the application of such information-theoretic measures, and demonstrates how they can be treated naturally side-by-side along traditional metrics used in HCI research. It emphasises the acquisition cost of accurate theoretical models, necessary to ensure the reliability of such measures.

This thesis explores the gap between theory and practice within the context of humancomputer interaction (HCI), specifically relating to effective implementation of HCI methods and frameworks within practice. The thesis is structured as follows: three connected but stand-alone papers are presented preceded by an introduction, and followed by a conclusion. The introduction defines HCI, discusses its history and evolution, and how it has been influenced by different disciplines. The first paper covers the usability of personalisation of Web sites and consists of three quantitative studies. The main measurements are effciency, effectiveness, and satisfaction as indicators of usability. Two of the studies show a significant relationship between the amount of content on a page and time taken to find information. The third study shows that when users are only allowed 3-5 seconds to glance through the page (skim), the significance, found in the other two studies, disappeared. There is, however, no indication that subjective satisfaction is affected, regardless of the amount of time users take to find information in any of the studies. The second paper is a case study: a practical evaluation of how usability is implemented in commercial website design projects. It compares the difference between targeting usability issues early in the design and later in the development. The third paper conceptualises involving users early on in design projects, how this affects design projects in the context of Garrett's (2002) framework and how it compares with current and optimal approaches. It shows that involving users early in the design process does not negatively affect time or effort and concludes by defining areas where research should concentrate to provide further evidence towards involving stakeholders in Web design through researchable propositions. Finally, the conclusion chapter summarises each of the paper's limitations and conclusions. It links the three papers through a discussion on how they are related in addition to how this research could benefit the practitioner

[EN] Computers are now present everywhere, but their potential is not fully exploited due to some lack of acceptance. In this thesis, the pen computer paradigm is adopted, whose main idea is to replace all input devices by a pen and/or the fingers, given that the origin of the rejection comes from using unfriendly interaction devices that must be replaced by something easier for the user. This paradigm, that was was proposed several years ago, has been only recently fully implemented in products, such as the smartphones. But computers are actual illiterates that do not understand gestures or handwriting, thus a recognition step is required to "translate" the meaning of these interactions to computer-understandable language. And for this input modality to be actually usable, its recognition accuracy must be high enough. In order to realistically think about the broader deployment of pen computing, it is necessary to improve the accuracy of handwriting and gesture recognizers. This thesis is devoted to study different approaches to improve the recognition accuracy of those systems. First, we will investigate how to take advantage of interaction-derived information to improve the accuracy of the recognizer. In particular, we will focus on interactive transcription of text images. Here the system initially proposes an automatic transcript. If necessary, the user can make some corrections, implicitly validating a correct part of the transcript. Then the system must take into account this validated prefix to suggest a suitable new hypothesis. Given that in such application the user is constantly interacting with the system, it makes sense to adapt this interactive application to be used on a pen computer. User corrections will be provided by means of pen-strokes and therefore it is necessary to introduce a recognizer in charge of decoding this king of nondeterministic user feedback. However, this recognizer performance can be boosted by taking advantage of interaction-derived information, such as the user-validated prefix. Then, this thesis focuses on the study of human movements, in particular, hand movements, from a generation point of view by tapping into the kinematic theory of rapid human movements and the Sigma-Lognormal model. Understanding how the human body generates movements and, particularly understand the origin of the human movement variability, is important in the development of a recognition system. The contribution of this thesis to this topic is important, since a new technique (which improves the previous results) to extract the Sigma-lognormal model parameters is presented. Closely related to the previous work, this thesis study the benefits of using synthetic data as training. The easiest way to train a recognizer is to provide "infinite" data, representing all possible variations. In general, the more the training data, the smaller the error. But usually it is not possible to infinitely increase the size of a training set. Recruiting participants, data collection, labeling, etc., necessary for achieving this goal can be time-consuming and expensive. One way to overcome this problem is to create and use synthetically generated data that looks like the human. We study how to create these synthetic data and explore different approaches on how to use them, both for handwriting and gesture recognition. The different contributions of this thesis have obtained good results, producing several publications in international conferences and journals. Finally, three applications related to the work of this thesis are presented. First, we created Escritorie, a digital desk prototype based on the pen computer paradigm for transcribing handwritten text images. Second, we developed "Gestures à Go Go", a web application for bootstrapping gestures. Finally, we studied another interactive application under the pen computer paradigm. In this case, we study how translation reviewing can be done more ergonomically using a pen.<br>[ES] Hoy en día, los ordenadores están presentes en todas partes pero su potencial no se aprovecha debido al "miedo" que se les tiene. En esta tesis se adopta el paradigma del pen computer, cuya idea fundamental es sustituir todos los dispositivos de entrada por un lápiz electrónico o, directamente, por los dedos. El origen del rechazo a los ordenadores proviene del uso de interfaces poco amigables para el humano. El origen de este paradigma data de hace más de 40 años, pero solo recientemente se ha comenzado a implementar en dispositivos móviles. La lenta y tardía implantación probablemente se deba a que es necesario incluir un reconocedor que "traduzca" los trazos del usuario (texto manuscrito o gestos) a algo entendible por el ordenador. Para pensar de forma realista en la implantación del pen computer, es necesario mejorar la precisión del reconocimiento de texto y gestos. El objetivo de esta tesis es el estudio de diferentes estrategias para mejorar esta precisión. En primer lugar, esta tesis investiga como aprovechar información derivada de la interacción para mejorar el reconocimiento, en concreto, en la transcripción interactiva de imágenes con texto manuscrito. En la transcripción interactiva, el sistema y el usuario trabajan "codo con codo" para generar la transcripción. El usuario valida la salida del sistema proporcionando ciertas correcciones, mediante texto manuscrito, que el sistema debe tener en cuenta para proporcionar una mejor transcripción. Este texto manuscrito debe ser reconocido para ser utilizado. En esta tesis se propone aprovechar información contextual, como por ejemplo, el prefijo validado por el usuario, para mejorar la calidad del reconocimiento de la interacción. Tras esto, la tesis se centra en el estudio del movimiento humano, en particular del movimiento de las manos, utilizando la Teoría Cinemática y su modelo Sigma-Lognormal. Entender como se mueven las manos al escribir, y en particular, entender el origen de la variabilidad de la escritura, es importante para el desarrollo de un sistema de reconocimiento, La contribución de esta tesis a este tópico es importante, dado que se presenta una nueva técnica (que mejora los resultados previos) para extraer el modelo Sigma-Lognormal de trazos manuscritos. De forma muy relacionada con el trabajo anterior, se estudia el beneficio de utilizar datos sintéticos como entrenamiento. La forma más fácil de entrenar un reconocedor es proporcionar un conjunto de datos "infinito" que representen todas las posibles variaciones. En general, cuanto más datos de entrenamiento, menor será el error del reconocedor. No obstante, muchas veces no es posible proporcionar más datos, o hacerlo es muy caro. Por ello, se ha estudiado como crear y usar datos sintéticos que se parezcan a los reales. Las diferentes contribuciones de esta tesis han obtenido buenos resultados, produciendo varias publicaciones en conferencias internacionales y revistas. Finalmente, también se han explorado tres aplicaciones relaciones con el trabajo de esta tesis. En primer lugar, se ha creado Escritorie, un prototipo de mesa digital basada en el paradigma del pen computer para realizar transcripción interactiva de documentos manuscritos. En segundo lugar, se ha desarrollado "Gestures à Go Go", una aplicación web para generar datos sintéticos y empaquetarlos con un reconocedor de forma rápida y sencilla. Por último, se presenta un sistema interactivo real bajo el paradigma del pen computer. En este caso, se estudia como la revisión de traducciones automáticas se puede realizar de forma más ergonómica.<br>[CAT] Avui en dia, els ordinadors són presents a tot arreu i es comunament acceptat que la seva utilització proporciona beneficis. No obstant això, moltes vegades el seu potencial no s'aprofita totalment. En aquesta tesi s'adopta el paradigma del pen computer, on la idea fonamental és substituir tots els dispositius d'entrada per un llapis electrònic, o, directament, pels dits. Aquest paradigma postula que l'origen del rebuig als ordinadors prové de l'ús d'interfícies poc amigables per a l'humà, que han de ser substituïdes per alguna cosa més coneguda. Per tant, la interacció amb l'ordinador sota aquest paradigma es realitza per mitjà de text manuscrit i/o gestos. L'origen d'aquest paradigma data de fa més de 40 anys, però només recentment s'ha començat a implementar en dispositius mòbils. La lenta i tardana implantació probablement es degui al fet que és necessari incloure un reconeixedor que "tradueixi" els traços de l'usuari (text manuscrit o gestos) a alguna cosa comprensible per l'ordinador, i el resultat d'aquest reconeixement, actualment, és lluny de ser òptim. Per pensar de forma realista en la implantació del pen computer, cal millorar la precisió del reconeixement de text i gestos. L'objectiu d'aquesta tesi és l'estudi de diferents estratègies per millorar aquesta precisió. En primer lloc, aquesta tesi investiga com aprofitar informació derivada de la interacció per millorar el reconeixement, en concret, en la transcripció interactiva d'imatges amb text manuscrit. En la transcripció interactiva, el sistema i l'usuari treballen "braç a braç" per generar la transcripció. L'usuari valida la sortida del sistema donant certes correccions, que el sistema ha d'usar per millorar la transcripció. En aquesta tesi es proposa utilitzar correccions manuscrites, que el sistema ha de reconèixer primer. La qualitat del reconeixement d'aquesta interacció és millorada, tenint en compte informació contextual, com per exemple, el prefix validat per l'usuari. Després d'això, la tesi se centra en l'estudi del moviment humà en particular del moviment de les mans, des del punt de vista generatiu, utilitzant la Teoria Cinemàtica i el model Sigma-Lognormal. Entendre com es mouen les mans en escriure és important per al desenvolupament d'un sistema de reconeixement, en particular, per entendre l'origen de la variabilitat de l'escriptura. La contribució d'aquesta tesi a aquest tòpic és important, atès que es presenta una nova tècnica (que millora els resultats previs) per extreure el model Sigma- Lognormal de traços manuscrits. De forma molt relacionada amb el treball anterior, s'estudia el benefici d'utilitzar dades sintètiques per a l'entrenament. La forma més fàcil d'entrenar un reconeixedor és proporcionar un conjunt de dades "infinit" que representin totes les possibles variacions. En general, com més dades d'entrenament, menor serà l'error del reconeixedor. No obstant això, moltes vegades no és possible proporcionar més dades, o fer-ho és molt car. Per això, s'ha estudiat com crear i utilitzar dades sintètiques que s'assemblin a les reals. Les diferents contribucions d'aquesta tesi han obtingut bons resultats, produint diverses publicacions en conferències internacionals i revistes. Finalment, també s'han explorat tres aplicacions relacionades amb el treball d'aquesta tesi. En primer lloc, s'ha creat Escritorie, un prototip de taula digital basada en el paradigma del pen computer per realitzar transcripció interactiva de documents manuscrits. En segon lloc, s'ha desenvolupat "Gestures à Go Go", una aplicació web per a generar dades sintètiques i empaquetar-les amb un reconeixedor de forma ràpida i senzilla. Finalment, es presenta un altre sistema inter- actiu sota el paradigma del pen computer. En aquest cas, s'estudia com la revisió de traduccions automàtiques es pot realitzar de forma més ergonòmica.<br>Martín-Albo Simón, D. (2016). Contributions to Pen & Touch Human-Computer Interaction [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/68482<br>TESIS

This work describes a software engine which works with textual documents containing historical information. The purpose of this work three-fold: firstly to show the validity of the developed engine to correctly identify and label the entities of the universe of discourse with a labelled-combined XTM-DITA model. Secondly to analyze the improvements achieved in the interaction between people (users) and computers with a practical application of the designed methodology to a real-world problem in the semantic web area and thirdly to plan its future integration into a traceability system.

ITSs (Intelligent Tutoring Systems) provide a way of addressing some of the issues that the more traditional CAI (Computer Aided Instruction) systems do not address - the individual learning needs and individual learning abilities and levels of users - so that the user is in control of their learning experience. An ITS needs to be able to provide an explanation, for a real world situation, that successfully meets the needs of the user. To ensure relevant explanation content requires the ITS be based on sound planning principles and tutoring knowledge as well as knowledge of the domain and the user. To ensure a coherent explanation structure requires that the tutoring knowledge be applied with full recognition of the knowledge of the domain and the user. For a model of the user's knowledge to be effective, the system should be able to use it to enhance the flexibility and responsiveness of explanations generated. A user model should guide the generation of explanations so they are pitched at the correct level of the user's existing knowledge; models should be able to actively support the needs of the user so that the user's efforts in seeking out information are minimised. The aim of this research is to generate effective, flexible and responsive explanations, in educational software systems, through developing better explanation facilities than exist in currently available ITS software. In achieving this aim, I am advancing research into dialogue planning and user modelling. The explanation facilities described meet the requirements of an explanation that is tailored to the user's needs, a sound theory from which particular explanations are constructed, and a user model that can accurately represent the behaviour and beliefs of the user. My research contributions include explicitly and formally representing discourse planning / reasoning, from both the user's view and the tutor's view so that they can be clearly understood and represented in the ITS. More recent planners have adopted approaches that can be characterised as using adaptations of the classical planning approach, with informally specified planning algorithms and planning languages. Without clear, explicit and full descriptions of actions and the planning algorithm we can not be certain of the plans that such planners produce. I adopt a theoretically rigorous approach based on classical planning theory - the actions available to the planner, the planning language and algorithm should be explicitly represented to ensure that plans are complete and consistent. Classical regression planning uses dynamic planning thus enabling the system to be flexible in a variety of situations and providing the responsiveness required for an ITS. I take a theoretically rigorous approach in constructing a well specified model of discourse, building upon existing research in the area. I present a tutoring module that is able to find a way to motivate the user to take a recommended action, by relating the action to the user's goals, and that is able to reason about the text structure to generate an effective explanation - putting together several clauses of text whilst maintaining coherency. As part of developing such constructs for motivating, enabling and recommending, as well as constructs for structuring text, I use a pedagogic model based on the principled approach of (i) advising the user to take an action (ii) motivating the user to want to take the action and (iii) ensuring the user knows how to do the action. I take a clear and realistic approach to user modelling, making explicit models of the user's behaviour and beliefs. I adopt a theoretically rigorous approach, formally distinguishing between the user's reasoning and their actions, so they can be focused on separately. Formally making this distinction, more easily enables models of the user's reasoning to be tailored to the individual user. To enable the tutor to consider the full impact on the user, of the information to be delivered to the user, I use different plan spaces. I explicitly identify the different perspectives of the user and the tutor so that they can be focused on separately to generate an explanation that is tailored to the user. In my approach, reasoning about the user's skills, rules and knowledge is independent from reasoning about those of the tutor.

ITSs (Intelligent Tutoring Systems) provide a way of addressing some of the issues that the more traditional CAI (Computer Aided Instruction) systems do not address - the individual learning needs and individual learning abilities and levels of users - so that the user is in control of their learning experience. An ITS needs to be able to provide an explanation, for a real world situation, that successfully meets the needs of the user. To ensure relevant explanation content requires the ITS be based on sound planning principles and tutoring knowledge as well as knowledge of the domain and the user. To ensure a coherent explanation structure requires that the tutoring knowledge be applied with full recognition of the knowledge of the domain and the user. For a model of the user's knowledge to be effective, the system should be able to use it to enhance the flexibility and responsiveness of explanations generated. A user model should guide the generation of explanations so they are pitched at the correct level of the user's existing knowledge; models should be able to actively support the needs of the user so that the user's efforts in seeking out information are minimised. The aim of this research is to generate effective, flexible and responsive explanations, in educational software systems, through developing better explanation facilities than exist in currently available ITS software. In achieving this aim, I am advancing research into dialogue planning and user modelling. The explanation facilities described meet the requirements of an explanation that is tailored to the user's needs, a sound theory from which particular explanations are constructed, and a user model that can accurately represent the behaviour and beliefs of the user. My research contributions include explicitly and formally representing discourse planning / reasoning, from both the user's view and the tutor's view so that they can be clearly understood and represented in the ITS. More recent planners have adopted approaches that can be characterised as using adaptations of the classical planning approach, with informally specified planning algorithms and planning languages. Without clear, explicit and full descriptions of actions and the planning algorithm we can not be certain of the plans that such planners produce. I adopt a theoretically rigorous approach based on classical planning theory - the actions available to the planner, the planning language and algorithm should be explicitly represented to ensure that plans are complete and consistent. Classical regression planning uses dynamic planning thus enabling the system to be flexible in a variety of situations and providing the responsiveness required for an ITS. I take a theoretically rigorous approach in constructing a well specified model of discourse, building upon existing research in the area. I present a tutoring module that is able to find a way to motivate the user to take a recommended action, by relating the action to the user's goals, and that is able to reason about the text structure to generate an effective explanation - putting together several clauses of text whilst maintaining coherency. As part of developing such constructs for motivating, enabling and recommending, as well as constructs for structuring text, I use a pedagogic model based on the principled approach of (i) advising the user to take an action (ii) motivating the user to want to take the action and (iii) ensuring the user knows how to do the action. I take a clear and realistic approach to user modelling, making explicit models of the user's behaviour and beliefs. I adopt a theoretically rigorous approach, formally distinguishing between the user's reasoning and their actions, so they can be focused on separately. Formally making this distinction, more easily enables models of the user's reasoning to be tailored to the individual user. To enable the tutor to consider the full impact on the user, of the information to be delivered to the user, I use different plan spaces. I explicitly identify the different perspectives of the user and the tutor so that they can be focused on separately to generate an explanation that is tailored to the user. In my approach, reasoning about the user's skills, rules and knowledge is independent from reasoning about those of the tutor.

In this thesis we propose novel methods for 3D interaction on 3D environments. The evaluation of these methods was performed based on three interaction environments: 3D interaction using portable multi-touch devices, 3D hand gesture data manipulation using 3D database representation and 3D multi-threaded programing using hand gesture interaction. The three experiments provided qualitative and quantitative information to evaluate the features of the presented interfaces. The first experiment, based on the use on the use of portable multi-touch devices, aimed to evaluate the use of 3D movements to interact under a 3D environment. Also, the possibility of generate collaborative interaction under 3D interfacing (simulating a 3D multi-touch table top environment) was evaluated. The second experiment consisted on 3D touchless data manipulation, removing the intermediate device (portable multi-touch) and providing hand gesture data interaction using the Kinect device. Furthermore, this evaluation was conducted over a 3D cube database model, based on the concepts of multidimensional databases and graphic databases. The third experiment intended to evaluate the possibility of software generation using a 3D interaction environment, following a similar model of interaction from the second experiment, but providing a better two handed interaction. The environment aimed multi-threaded programing under a 3D interface. The three experiments provided valuable data about users’ interaction and preference, which were tested with users of different ages and levels of knowledge. The research process and results are summarized in this research work.

People began to interact with their own environment since their birth. Their main organs to sense their surroundings are their hands, and this is the most natural way of interaction in human-human interactions. The goal of this dissertation is to enable users to employ their hands in interaction with computers similar to human-human interaction. Using hands in the computer interaction increases both the naturalness of computer usage and the speed of interaction. One way of accomplishing this goal is to utilize computer vision methods to develop hand interfaces. In this study, a regular, low-cost camera is used for image acquisition, and the images from camera are processed by our novel vision system to detect user intention. The contributions are (i) a method for interacting with a screen without touching in a distributed computer system is proposed, (ii) a benchmark of four hand shape representation methods is performed using a comprehensive hand shape video database, and (iii) a vison-based hand interface is designed for an application that queries a video database system, and its usability and performances are also assessed by a group of test users to determine its suitability for the application.

Communication, simulation, interactive narrative and ubiquitous computing are widely accepted as perspectives in humancomputer interaction. This paper proposes play as another possible perspective. Everyday uses of the computer increasingly show signs of similarity to play. This is not discussed with regard to the so-called media society, the playful society, the growing cultural acceptance of the computer, the spread of computer games or a new version of Windows, but in view of the playful character of interaction with the computer that has always been part of it. The exploratory learning process involved with new software and the creative tasks that are often undertaken when using the computer may support this argument. Together with its high level of interactivity, these observations point to a sense of security, autonomy and freedom of the user that produce play and are, in turn, produced by play. This notion of play refers not to the playing of computer games, but to an implicit, abstract (or symbolic) process based on a certain attitude, the play spirit. This attitude is discussed regarding everyday computer use and related to the other mentioned perspectives.

Humans live in physical world and perform activities that are physical, natural and biological. But humans are forced to shift explicitly from physical world to virtual world and vice-versa in performing computer aided physical activities. The research reported here is investigating: How implicit human-computer interaction can be used as a means to bridge the gap between physical world and virtual world. An agent-centric approach is introduced to extend ubiquitous computing to unlimited geographical space and a framework for implicit human-computer interaction is also discussed. The benefits of standardized ontologies are used as a base upon which this framework is built. This semantic approach together with agent-centric approach is discussed to visualize the visions of implicit Human-Computer Interaction (i-HCI).<br>PHYVIR project