Abstract
The paper presents a multimedia database model accounting for the representation of documents, collections and the associated metadata. Appropriate structures are provided for descriptive metadata and for metadata resulting from automatic content analysis. The model is based on the identification and unification of the main concepts in the archival standards and the audiovisual area. The main features of the model, designed to support multimedia database applications, axe the integration of descriptive and content analysis metadata, the association of metadata to collections as well as to items, the extensibility with respect to the inclusion of new descriptors and the support to several retrieval modes. The MetaMedia application development platform, based on the model, has been used to support the construction of a historic documentation collection where a common web interface provides collection administrators, metadata creators and visitors a multi-faceted view of the repository.

Abstract

Abstract
The efficiency of network attachment plays a crucial role in the performance of accessing services in new environments. As an example, when a moving network is changing its location relative to attachment points, the detection of the candidate access networks along with their properties and security relationships needs to be carefully managed. This paper presents the framework and mechanisms for network attachment of Ambient Networks. Different steps required for optimizing the network attachment procedure are studied, and a secure network attachment protocol is proposed.

Abstract
The web is currently the information searching and browsing environment of choice for scholars and lay users alike. The goal of most cultural heritage applications is to interest a large audience, and therefore web interfaces are being developed even when part of their functionality is not offered to the general public. We present a web-based interface for managing, browsing and searching a repository of historic documents. The documents pertain to a region which has been an important regional power in medieval times and their originals are under the custody of the Portuguese national archives. The challenges of the project came from its requisites in three aspects: rigorous archival description, the incorporation of document analysis and a flexible search interface. The system is an instance of a multimedia database framework providing both browse and retrieval functionalities to end users and configuration and content management services to the collection administrators.

Abstract
Keeping up with the timing constraints of real-time traffic in wireless environments is a hard task. One of the reasons is that the real-time stations have to share the same communication medium with stations that are out of the sphere-of-control of the real-time architecture. That is, with stations that generate timing unconstrained traffic. The VTP-CSMA architecture targets this problem in IEEE 802.11 wireless networks. It is based on a Virtual Token Passing procedure (VTP) that circulates a virtual token among real-time stations, enabling the coexistence of real-time and non real-time stations in a shared communication environment. The worst-case timing analysis of the VTP-CSMA mechanism shows that the token rotation time is upper-bounded, even when the communication medium is shared with timing unconstrained stations. Additionally, the simulation analysis shows that the token rotation mechanism behaves adequately, even in the presence of error-prone communication channels. Therefore, the VTP-CSMA architecture enables the support of real-time communication in shared communication environments, without the need to control the timing behavior of every communicating device. A ring management procedure for the VTP-CSMA architecture is also proposed, allowing real-time stations to adequately join/leave the virtual ring. This ring management procedure is mandatory for dynamic operating scenarios, such as those found in VoIP applications. © 2007 IEEE.

Abstract
This paper presents two evolutionary schemes and a swarm intelligence algorithm for the design of combinational logic circuits. A Genetic and a Memetic schemes as the evolutionary algorithms. The Particle Swarm Optimization as the swarm algorithm. The fitness function used in these three algorithms is sequential, that is, divided in two parts. The first part of the fitness function f(1) evaluates the circuit functionality, while the second part f(2) deals with the circuit complexity. The experiments consist in applying the algorithms in the design of two arithmetic circuits: the one-bit full adder and the one-bit full subtractor. We also present a scalability analysis using the parity checker family of circuits.