Cookies
O website necessita de alguns cookies e outros recursos semelhantes para funcionar. Caso o permita, o INESC TEC irá utilizar cookies para recolher dados sobre as suas visitas, contribuindo, assim, para estatísticas agregadas que permitem melhorar o nosso serviço. Ver mais
Aceitar Rejeitar
  • Menu
Publicações

2005

A tool for fast development of modular and hierarchic neural network-based systems

Autores
Reinaldo, F; Roisenberg, M; Barreto, JM; Camacho, R; Reis, LP;

Publicação
Modelling and Simulation 2005

Abstract
This paper presents the PyrantidNet Tool its a fast and easy way to develop Modular and Hierarchic Neural Network-based Systems. This tool facilitates the fast emergence of autonomous behaviours in agents because it uses a hierarchic and modular control methodology of heterogeneous learning modules: the pyramid. Using the graphical resources of PyramidNet the user is able to specify a behaviour system even having little understanding of artificial neural networks. Experimental tests have shown that a very significant speedup is attained in the development of modular and hierarchic neural network-based systems when using this tool.

2005

Group-based replication of on-line transaction processing servers

Autores
Correia, A; Sousa, A; Soares, L; Pereira, J; Moura, F; Oliveira, R;

Publicação
DEPENDABLE COMPUTING, PROCEEDINGS

Abstract
Several techniques for database replication using group communication have recently been proposed, namely, the Database State Machine, PostgresR, and the NODO protocol. Although all rely on a totally ordered multicast for consistency, they differ substantially on how multicast is used. This results in different performance trade-offs which are hard to compare as each protocol is presented using a different load scenario and evaluation method. In this paper we evaluate the suitability of such protocols for replication of On-Line Transaction Processing (OLTP) applications in clusters of servers and over wide area networks. This is achieved by implementing them using a common infra-structure and by using a standard workload. The results allows us to select the best protocol regarding performance and scalability in a demanding but realistic usage scenario.

2005

Metaheuristics applied to mixed and simultaneous extensions of vehicle routing problems with backhauls

Autores
Crispim, J; Brandao, J;

Publicação
JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY

Abstract
Metaheuristics are a class of approximate methods designed to solve hard combinatorial optimization problems arising within various different areas. The importance of metaheuristics results from their ability to continue the search beyond a local optimum so that near-optimal or optimal solutions are efficiently found. In order to solve the backhauling problem associated with mixed and simultaneous delivery and pick-ups, this paper presents a hybrid algorithm which is comprised of the two metaheuristics of tabu search and variable neighbourhood descent. The primary challenge associated with backhauling consists of creating routes in which vehicles are not only required to deliver goods, but also to perform pick-ups at customer locations. The problems associated with these two categories of problems, however, have received little attention in the literature to date. A set of examples taken from the literature with Euclidean cost matrices are presented. Finally, some numerical results are illustrated to show the effectiveness of the proposed approach.

2005

WAVE: Sound and music in an immersive environment

Autores
Valbom, L; Marcos, A;

Publicação
COMPUTERS & GRAPHICS-UK

Abstract
This paper presents WAVE-a Virtual Audio Environment, which embraces the implementation of an immersive musical instrument model that uses three-dimensional (3D) sound techniques combined with visualisation and virtual reality technologies. This prototype environment aims to extend the idea of a musical instrument into a new musical/ audio system, incorporating traditional musical concepts side by side with actual music concepts, in order to progress one step further in the music/sound composing and performing approaches. The architecture of the system is based on low-cost hardware and open source software with affordable professional audio equipment to maintain an adequate sound quality. Also several applications of this virtual environment are discussed in the paper, including the way to satisfy at the same time composers, performers, music/audio students or even simple occasional users.

2005

Protocol conformance using a progressive test approach

Autores
Mamede, J; Carrapatoso, E; Ricardo, M;

Publicação
PROCEEDINGS OF THE SECOND IASTED INTERNATIONAL MULTI-CONFERENCE ON AUTOMATION, CONTROL, AND INFORMATION TECHNOLOGY - COMMUNICATION SYSTEMS

Abstract
The development of communications systems demands testing. This paper presents a framework for testing on-the-fly, which relies on the definition of 3 types of tests and on their sequential execution. The ioco conformance relation was considered in order to assign verdicts. A tool prototype is also presented that supports the proposed framework. This tool, named PROFYT, was developed based on the SPIN verifier, and uses communicating FSMs to describe the specification. The test of Conference Protocol implementations was carried out on-the-fly with PROFYT and enabled us to conclude about the benefits of the test methodology proposed.

2005

Optical fiber sensors for nuclear environments

Autores
Rego G.M.; Fernandez A.F.; Santos J.L.; Salgado H.M.; Berghmans F.; Gusarov A.;

Publicação
Recent Advances in Multidisciplinary Applied Physics

Abstract

  • 4225
  • 4541