[pt] A tecnologia de jogos multi-jogador é uma especialização dentro da área de ambientes virtuais distribuídos. Com a crescente popularidade de jogos pela Internet, torna-se interessante analisar os seus principais problemas e encontrar soluções de arquiteturas destes ambientes, a fim de adaptá-las para as necessidades específicas destes jogos. Uma arquitetura híbrida usando as abordagens cliente- servidor e peer-to-peer é proposta e implementada neste trabalho, visando atender uma certa classe de jogos multi- jogador. Com o objetivo de permitir uma eficiente transmissão de objetos criados entre os jogadores durante uma sessão, é proposta uma alteração em sua forma de representação geométrica. É mostrado que técnicas de modelagem de mais alto nível como CSG ou Metaball podem ser usadas para permitir esta transmissão eficiente sob certas circunstâncias. É também proposta uma técnica eficiente de representação e transmissão de coordenadas do ambiente virtual usando campos de bits. / [en] Multiplayer game technology is a specialized field in networked virtual environments (Net-VE). With the increasing popularity of Internet games, the analysis of their main problems and the search for an architecture for these environments has become interesting in order to adapt them to the specific needs of these games. A hybrid architecture using both client-server and peer-to-peer approach is proposed and implemented in this work for a certain class of multiplayer games. In order to provide an efficient transmission of user created objects among players during a session, a change in its geometrical representation is proposed. It is showed that the use of higher level object representation such as CSG or Metaball modeling techniques can be used to provide this efficient transmission under certain circumstances. It is also proposed the use of bitfields as a efficient way to both represent and transmit coordinates of the virtual world.

Made available in DSpace on 2016-04-04T18:31:36Z (GMT). No. of bitstreams: 1 Vitor Chaves de Oliveira.pdf: 1928054 bytes, checksum: 49bf6198a68438069d6ef8b9a2ec77e9 (MD5) Previous issue date: 2012-12-10 / In recent years, virtualization computing has become a worldwide reality present in datacenters servers of most organizations. The motivations for the use of this solution are focused primarily on cost reduction and increases in availability, integrity and security of data. Based on these benefits, recently it was started the use of this technology for personal computers as well. That is, for desktops, giving birth to the so-called desktop virtualization. Given the technical advantages of the approach, its growth has been so significant that, before 2014, it is expected to be present in over 90% of organizations. However, this new method is completely based on a physical client-server architecture, which increases the importance of the communication network that makes this technique possible. Therefore, analyzing the network in order to investigate the effects according to the environment implemented, becomes crucial. In this work it s varied the local s client hardware and the application, i.e. the service used. The purpose was to detail their effects on computer networks in a Quality of Service (QoS) parameter, throughput. Secondarily are outlined perceptions regarding the Quality of Experience (QoE). / Nos ?ltimos anos, a virtualiza??o computacional se tornou uma realidade nos servidores presentes nos data-centers da maioria das organiza??es no mundo. As motiva??es para o emprego desta solu??o est?o centradas, primordialmente, na redu??o de custos e em aumentos na disponibilidade, na integridade e na seguran?a dos dados. Com base nestes benef?cios, recentemente, se come?ou a aproveitar esta tecnologia tamb?m para os computadores pessoais. Isto ?, para os desktops, dando origem a chamada virtualiza??o de desktop. Dadas as vantagen t?cnicas da abordagem, seu crescimento tem sido t?o expressivo que, antes de 2014, se espera que ela esteja presente em mais de 90% das organiza??es. Todavia, este m?todo ? totalmente baseado em uma arquitetura cliente-servidor f?sica, o que aumenta a import?ncia da rede de comunica??o que torna a t?cnica poss?vel. Logo, analisar a rede, a fim de investigar os impactos de acordo com o ambiente implementado, se torna fundamental. Neste trabalho variamos o hardware local do cliente e a aplica??o, isto ?, o servi?o utilizado. A finalidade foi a de detalhar seus efeitos, em redes de computadores, em um par?metro de Qualidade de Servi?o (QoS), a vaz?o. Secundariamente s?o esbo?adas percep??es de Qualidade da Experi?ncia (QoE).

The main goal of this work is creating client-server application with image processing and cryptographic verification of image source and creation time. The work focuses on creating a mobile client application on the Android platform that securly takes photos by mobile device camera, processes captured images and provides a digital signature, timestamp and GPS location. The main part of the work is secure key exchange, encrypted communication, data and energy efficiency of the client-server application. The server application is implemented on the Java EE platform and processes the received image, performs object detection, object recognition in the image and provides a timestamp from a trusted server. Then taken photo can be considered as a trusted electronic document usable as valid evidence for the judical or administrative proceedings.