Economic models and algorithms for distributed systems

Distributed computing paradigms for sharing resources such as Clouds, Grids, Peer-to-Peer systems, or voluntary computing are becoming increasingly popular. While there are some success stories such as PlanetLab, OneLab, BOINC, BitTorrent, and SETI@home, a widespread use of these technologies for business applications has not yet been achieved. In a business environment, mechanisms are needed to provide incentives to potential users for participating in such networks. These mechanisms may range from simple non-monetary access rights, monetary payments to specific policies for sharing. Although a few models for a framework have been discussed (in the general area of a "Grid Economy"), none of these models has yet been realised in practice. This book attempts to fill this gap by discussing the reasons for such limited take-up and exploring incentive mechanisms for resource sharing in distributed systems. The purpose of this book is to identify research challenges in successfully using and deploying resource sharing strategies in open-source and commercial distributed systems.

Distributed systems and multimedia

Edited book to support level 3 undergraduate understanding.

SMART: system of augmented reality for teaching

Os computadores e os jogos de consola, são um vocabulário bem comum dos jovens e das crianças de hoje. No entanto, na maior parte das escolas, o processo de ensino-aprendizagem continua a ser feito da forma tradicional através do recurso aos quadros pretos e aos cadernos. Este projecto pretende mostrar que, se as aulas forem dadas de uma forma mais interactiva, as crianças estarão mais motivadas e consequentemente a taxa de aprendizagem terá tendência a aumentar. Pretende-se então, utilizar a tecnologia – a Realidade Aumentada, acreditando que será uma mais valia para o ensino, pois permite estabelecer novas relações com o saber, ultrapassando os limites dos materiais tradicionais e contribuindo para a diminuição da distância entre os alunos e o conhecimento.

SysteM of augmented reality for teaching kids: smartkids

As crianças do jardim de infância/pré-escola são um grupo de utilizadores muito especiais, uma vez que se encontram numa fase inicial das suas vidas onde têm de aprender a viver em sociedade, isto é, aprender a ouvir e respeitar as opiniões dos outros, partilhar os mesmos objectos e também a ajudar-se mutuamente. Este estudo mostra que através da utilização da tecnologia Realidade Aumentada, estas crianças são capazes de colaborar de uma forma espontânea suportada pela motivação, envolvimento e curiosidade. Descreve-se o design e a avaliação de um jogo de Realidade Aumentada, que consiste num sistema educativo para o ensino de crianças do pré-escolar. Este jogo permite que as crianças explorem conceitos tais como os animais e os meios onde vivem através de marcadores de Realidade Aumentada e de um tabuleiro de madeira. Estes marcadores consistem nas peças do jogo e através deles, as crianças podem manipular objectos virtuais em 3D. Foram realizados testes com diversas turmas de crianças em diferentes ambientes de aprendizagem, nomeadamente em escolas e num museu. Os resultados sugerem que o jogo é eficaz para obter níveis altos de concentração, motivação e colaboração entre as crianças, particularmente quando o feedback do jogo é fornecido de forma imediata. Os resultados mostram também que o jogo tem um impacto positivo sobre a experiência de aprendizagem das crianças.

ARBOT: augmented reality system for teaching logic algorithmic

This article purposes the ARBot, a system that has as main objective the presentation of concepts of logic for students of elementary and secondary education. The system was developed using the technology known as Augmented Reality (AR), which allows complement the actual environment where the user is, by adding virtual objects. In this scenario the RA created from a virtual game interface is used, through which cognitive challenges are presented. To solve these challenges, users must set up three-dimensional virtual characters using visual language. As a result it follows that, in a playful way, concepts of algorithms and programming are assimilated by users. In addition, the system enables two users to interact in a cooperative game mode. In cooperative mode, the system focuses on collaborative learning, since it allows users to jointly solve the cognitive challenge presented by the system.

An online data access prediction and optimization approach for distributed systems

Current scientific applications have been producing large amounts of data. The processing, handling and analysis of such data require large-scale computing infrastructures such as clusters and grids. In this area, studies aim at improving the performance of data-intensive applications by optimizing data accesses. In order to achieve this goal, distributed storage systems have been considering techniques of data replication, migration, distribution, and access parallelism. However, the main drawback of those studies is that they do not take into account application behavior to perform data access optimization. This limitation motivated this paper which applies strategies to support the online prediction of application behavior in order to optimize data access operations on distributed systems, without requiring any information on past executions. In order to accomplish such a goal, this approach organizes application behaviors as time series and, then, analyzes and classifies those series according to their properties. By knowing properties, the approach selects modeling techniques to represent series and perform predictions, which are, later on, used to optimize data access operations. This new approach was implemented and evaluated using the OptorSim simulator, sponsored by the LHC-CERN project and widely employed by the scientific community. Experiments confirm this new approach reduces application execution time in about 50 percent, specially when handling large amounts of data.

Augmented reality in sport scenarios using cameras mounted on a tripod

[ES] In this paper we address the problem of inserting virtual content in a video sequence. The method we propose uses just image information. We perform primitive tracking, camera calibration, real and virtual camera synchronisation and finally rendering to insert the virtual content in the real video sequence. To simplify the calibration step we assume that cameras are mounted on a tripod (which is a common situation in practise). The primitive tracking procedure, which uses lines and circles as primitives, is performed by means of a CART (Classification and Regression Tree). Finally, the virtual and real camera synchronisation and rendering is performed using functions of OpenGL (Open Graphic Library). We have applied the method proposed to sport event scenarios, specifically, soccer matches. In order to illustrate its performance, it has been applied to real HD (High Definition) video sequences. The quality of the proposed method is validated by inserting virtual elements in such HD video sequence.