Abstract
Vehicle number plate recognition systems are expected to have numerous applications in traffic surveying and monitoring, e.g. finding stolen cars, controlling access to car parks and gathering traffic flow statistics. The Computer Vision Group at the University of Tras-os-Montes e Alto Douro, in collaboration with the Universities of Aveiro and Bristol, has been developing a number plate reading system [3][4][5]. The system builds on the experience gained by the Computer Vision Group at the University of Bristol while developing previous transputer based prototypes [5][6][8][12]. The main tasks of a number plate recognition system are the location of the number plate area in the image, the segmentation of the characters and their identification. These tasks are strongly inter-related, mainly because the way to check if the number plate has been correctly located is based on the result of the character identification process (it should correspond to a predefined syntax). Algorithmic improvements to previous versions of the system, based on the results of intensive testing, are described in the paper. For the location of the number plate area in the image, a new line-based method has been developed. The method, instead of looking for character like shapes in the image, takes advantage of the "signature" of the number plate area in a horizontal cross-section of the image. The method used for the segmentation of the characters is derived from a technique first proposed by Lu [8]. The identification of the characters uses the OCR engine developed by Barroso et al [3][4], based on the critical points method [10][11].

Abstract
Vehicle number plate recognition systems are expected to have numerous applications in traffic surveying and monitoring, e,g. finding stolen cars and controlling access to car parks. In this paper algorithmic improvements to a previous version of a number plate reading system are described. The work builds on the experience gained by the Computer Vision Group at the University of Bristol. This paper addresses the problem of locating the number plate area in the image and proposes a new line based method for number plate location, which is suitable for realtime number plate recognition.

Abstract
Ray-Tracing is a well known algorithm that simulates the reflection and refraction of light rays in the objects surfaces, beginning with rays sent from the view point. Each ray has to be tested against objects in the 3D scene and this is very time consuming. This paper describes one parallel solution. It is oriented to a general network, where each processor manages data and tasks and shares them with the others to optimise common resources utilisation. In this context, a Virtual Sharing Memory (VSM) is used and an efficient load balancing strategy can be implemented. With this approach, the amount of messages in the network tends to increase and strategies to reduce them are needed. Schemes to optimise remote accesses to data have been developed, namely a special type of multicast message addressing named InPathTo. © Springer-Verlag Berlin Heidelberg 1997.

Abstract

Abstract
Distributed systems emerged in the last decade as a more efficient way of sharing networked resources, allowing cooperating processes to be executed in remote computers with possibly distinct architectures and operating systems. This paper presents the motivations that may lead to the usage of distributed architectures in the support of telecommunications services, particularly multimedia services. It also gives an overview of one distributed architecture, ANSA, which was used to implement a prototype of a distributed multimedia service, briefly described.

Abstract
Technical advances in communication networks and terminal equipment make possible the provision of a wide range of new and appealing telecommunication services. However, the increasing user demand and the strong market competition require that the creation of those services is efficient and fast, and that they have attractive interfaces. The complexity of networks and distributed systems, which support those services, renders the usage of formal specification languages, such as SDL, almost mandatory in their development. According to some authors, fifty percent of the total time necessary to develop applications is spent in building and testing graphical interfaces for different platforms. In this paper, an efficient methodology to create graphical interfaces for telecommunication services specified in SDL is presented.