ARTiVIS Arts, real-time video and interactivity for sustainability

Dissertação para obtenção do Grau de Doutor em Media Digitais

Risky behaviour and HIV/AIDS-related stigma in Zimbabwe

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Do anti-retroviral treatments encourage individuals to get tested for HIV/AIDS in Sub-Saharan Africa?

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

O uso do video nos sites dos jornais impressos

DISSERTAÇÃO APRESENTADA PARA CUMPRIMENTO DOS REQUISITOS NECESSÁRIOS À OBTENÇÃO DO GRAU DE MESTRE EM (CIÊNCIAS DA COMUNICAÇÃO, VERTENTE DE CINEMA E TELEVISÃO),

Interactive acquisition of spatial information from images for multimedia applications

Dissertação para obtenção do Grau de Doutor em Informática

A framework for developing motion-based games

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Expanding the magic circle in pervasive casual play

Dissertação para obtenção do Grau de Doutor em Informática

Video interaction using pen-based technology

Dissertação para obtenção do Grau de Doutor em Informática

An existence result for discontinuous games

We introduce a notion of upper semicontinuity, weak upper semicontinuity, and show that it, together with a weak form of payoff security, is enough to guarantee the existence of Nash equilibria in compact, quasiconcave normal form games. We show that our result generalizes the pure strategy existence theorem of Dasgupta and Maskin (1986) and that it is neither implied nor does it imply the existence theorems of Baye, Tian, and Zhou (1993) and Reny (1999). Furthermore, we show that an equilibrium may fail to exist when, while maintaining weak payoff security, weak upper semicontinuity is weakened to reciprocal upper semicontinuity.

On the existence of pure-strategy equilibria in large games

Over the years, several formalizations and existence results for games with a continuum of players have been given. These include those of Schmeidler (1973), Rashid (1983), Mas-Colell (1984), Khan and Sun (1999) and Podczeck (2007a). The level of generality of each of these existence results is typically regarded as a criterion to evaluate how appropriate is the corresponding formalization of large games. In contrast, we argue that such evaluation is pointless. In fact, we show that, in a precise sense, all the above existence results are equivalent. Thus, all of them are equally strong and therefore cannot rank the different formalizations of large games.

Collusion and reciprocity in infinitely repeated games

This paper extends the standard industrial organization models of repeated interaction between firms by incorporating preferences for reciprocity. A reciprocal firm responds to unkind behavior of rivals with unkind actions (destructive reciprocity), while at the same time, it responds to kind behavior of rivals with kind actions (constructive reciprocity). The main finding of the paper is that, for plausible perceptions of fairness, preferences for reciprocity facilitate collusion in infinitely repeated market games, that is, the critical discount rate at wish collusion can be sustained tends to be lower when firms have preferences for reciprocity than when firms are selfish. The paper also finds that the best collusive outcome that can be sustained in the infinitely repeated Cournot game with reciprocal firms is worse for consumers than the best collusive outcome that can be sustained in the infinitely repeated Cournot game with selfish firms.

Narrative Memory in Hyperfiction and Games

The aim of this paper is to address some theoretical issues concerning the narrative practice in cyberspace. From a narratological perspective it intends to clarify the functioning of time and space in storytelling. For that purpose it traces the concept(s) of memory inherited from rhetoric; the use of memory as a narrative device in traditional accounts; the adaptations imposed by hyperfiction. Using practical examples (including two Portuguese case studies - InStory 2006, and Noon 2007) it will show how narrative memory strategies can be helpful in game literacy. The main purpose is to contribute to serious game research and (trans)literary studies.

Representar Fantasmas: Identidade nos Chats de Video Aleatório

Este texto falará de como é percepcionado o “outro” e como nos percepcionámos a nós mesmos através da comunicação em plataformas virtuais de tecnologias que utilizam sistemas de chats de video conhecidos como anónimos ou aleatórios, nomeadamente leituras sobre a vigilância existente, grafismo, design, capacidade de imersão, co-presença e de comunicação. Repararemos que este tipo de sites traz uma certa novidade aos mundos virtuais e reais. Por um lado, uma possibilidade de sermos anónimos (dada a liberdade que estes sites dão ao utilizador, sem uma autoridade hierárquica, cada um pode fazer o que lhe apetece até ser «rejeitado» pelo outro utilizador, através de um clique no botão "next"). Também pelo facto de ser um entre milhares de outros idênticos, todos enquadrados pela mesma janela (espaço homogéneo = população homogénea). A quase impossibilidade de voltarmos a ver o mesmo utilizador, online ou na vida real, dá-nos também a liberdade de agirmos como queremos. Por outro lado, os níveis de realismo no site são elevados porque a comunicação é baseada em webcams e microfones que dão uma representação muito aproximada da realidade, de modo que o utilizador se mostra mais ou menos tal como é. Neste sentido, neste antagonismo destas duas forças surge uma sensação paradoxal. Os utilizadores sentem-se como que a representar para fantasmas, mas são pessoas que estão ali também, corpos reais por trás de uma imagem. O próprio utilizador é como um fantasma que pode desaparecer ou esconder-se a qualquer momento, optar por estar ou não presente. É na fronteira entre estes dois mundos que a fantasia, jogos de papéis e personalidades e construção de identidades tomam lugar.

About using serious games to teach (Portuguese) sign language

Sign language is the form of communication used by Deaf people, which, in most cases have been learned since childhood. The problem arises when a non-Deaf tries to contact with a Deaf. For example, when non-Deaf parents try to communicate with their Deaf child. In most cases, this situation tends to happen when the parents did not have time to properly learn sign language. This dissertation proposes the teaching of sign language through the usage of serious games. Currently, similar solutions to this proposal do exist, however, those solutions are scarce and limited. For this reason, the proposed solution is composed of a natural user interface that is intended to create a new concept on this field. The validation of this work, consisted on the implementation of a serious game prototype, which can be used as a source for learning (Portuguese) sign language. On this validation, it was first implemented a module responsible for recognizing sign language. This first stage, allowed the increase of interaction and the construction of an algorithm capable of accurately recognizing sign language. On a second stage of the validation, the proposal was studied so that the pros and cons can be determined and considered on future works.

Benefits & drawbacks of different means of interaction for placing objects above a video footage

Public Display Systems (PDS) increasingly have a greater presence in our cities. These systems provide information and advertising specifically tailored to audiences in spaces such as airports, train stations, and shopping centers. A large number of public displays are also being deployed for entertainment reasons. Sometimes designing and prototyping PDS come to be a laborious, complex and a costly task. This dissertation focuses on the design and evaluation of PDS at early development phases with the aim of facilitating low-effort, rapid design and the evaluation of interactive PDS. This study focuses on the IPED Toolkit. This tool proposes the design, prototype, and evaluation of public display systems, replicating real-world scenes in the lab. This research aims at identifying benefits and drawbacks on the use of different means to place overlays/virtual displays above a panoramic video footage, recorded at real-world locations. The means of interaction studied in this work are on the one hand the keyboard and mouse, and on the other hand the tablet with two different techniques of use. To carry out this study, an android application has been developed whose function is to allow users to interact with the IPED Toolkit using the tablet. Additionally, the toolkit has been modified and adapted to tablets by using different web technologies. Finally the users study makes a comparison about the different means of interaction.