Guido Lemos

Analyzing the impact of elasticity on the profit of cloud computing providers

Bag-of-tasks (BoT) is an important class of scientific applications. These applications are typically comprised of a very large number of tasks that can be executed in parallel in an independent way. Due to its cost associativity property, a public cloud computing environment is, theoretically, the ideal platform to execute BoT applications, since it could allow them to be executed as fast as possible, yet without implying any extra costs for the rapid turnaround achieved. Unfortunately, current public cloud computing providers impose strict limits on the amount of resources that a single user can simultaneously acquire, substantially increasing the response time of large BoT applications. In this paper we analyze the reasons why traditional providers need to impose such a limit. We show that increases in the limit imposed have a severe impact on the profit achieved by providers. This leads to the conclusion that new approaches to deploy cloud computing services are required to properly serve BoT applications.

HYPERPRESENCE-an application environment for control of multi-user agents in mixed reality spaces

The HYPERPRESENCE system proposed in this work is a mix between hardware and software platforms developed for control of multi-user agents in a mixed reality environment. The hardware is basically composed of robot systems that manipulate objects and move in a closed, real environment and a video camera, imaging system. The environment can be any place that provides or needs interactions with virtual environments for showing results or else to allow manipulation in it via a virtual reality interface. The software part is composed of three main systems: an acquisition module for position control, a tower (hardware) communication module for manipulating the robots and a multi user VRML server for managing virtual spaces and to provide synchronism between the real places and the virtual ones. We present the design and implementation solution adopted for the HYPERPRESENCE architecture. We analyze problems with communication protocols, precision of positioning, how to relate physical and virtual objects and show our solutions for these problems.

Knowledge tv

While iTV content is aimed at human manipulation, it does not appropriately support the performance of computational processes, such as search engines. The principal problem is that the meaning of multimedia documents cannot be explored, reducing the actuation limit of services and applications. In this context, this project proposes the definition of a semantic layer to the iTV platform, based on the Semantic Web concepts, which organizes its content and offers intelligent services, such as semantic queries and recommendation. Thus, this project tries to avoid the same problems that are currently presented by the Web platform, following the Semantic Web trend and increasing the potential to the development of more advanced applications. This technology is being developed in accordance with the Ginga project, which is the official specification for the Brazilian iTV middleware.

QoS Specification and Management in a Middleware for Distributed Multimedia Systems

Multimedia systems should deal with critical issues such as real-time requirements of audio and video. Such requirements can become more complex when applications are executed in different platforms including different technologies, such as Internet and interactive digital television systems. In such a context, this paper proposes a QoS management and specification model to support adaptation in middleware for distributed multimedia systems

A component interconnection model for interactive digital television systems

Distributed multimedia systems should deal with critical issues such as temporal requirements of audio and video. Such requirements can become more complex when applications are executed in interactive digital television systems, since there is a diversity of hardware devices, operating systems and communication technologies. In order to fulfil the requirements of such applications, their constituting components need to interact with each other, as well to consider QoS issues related to devices and transmission media. This paper presents a generic interconnection model that allows communication between components in heterogeneous and distributed multimedia environments. Besides, the model supports adaptation in the middleware layer, triggered by QoS and user requirements changes.

An Open and Extensible Platform for Machine Translation of Spoken Languages into Sign Languages

The purpose of this paper is to investigate the feasibility of offering a multilingual platform for text-to-sign translation, i.e., a solution where a machine translates digital contents in several spoken languages to several sign languages in scenarios such as Digital TV, Web and Cinema. This solution called OpenSigns, is an open platform that has several common components for generic functionalities, initially originated from the Suite VLibras, including the creation and manipulation of 3D animation models, and interchangeable mechanisms specific for each sign language, such as a text-to-gloss machine translation engine, a sign dictionary for each sign language, among others. Our motivation is that the concentration of efforts and resources around a single solution could provide some state-of-the-art improvement, such as a standard solution for the industry and a greater functional flexibility for common components. In addition, we could also share techniques and heuristics between the translation mechanisms, reducing the effort to make a new sign language available on the platform, which may further enhance digital inclusion and accessibility, especially for poorest countries.

A framework for collaborative interaction of people and robots in the Web

We propose a multimedia framework built on a flexible architecture designed for collaborative interaction of people and robots through the Web. Users can communicate to each other exchanging text, audio and video messages. One or several users can communicate with one or more robots and also receive information from them. Robots can be remotely controlled through the use of keyboard, joysticks, data glove, and voice commands. A user can perceive other users through a virtual environment and receive the video from an environment, in which the robot is.