Abstract

Abstract
Four research projects used Second Life", a 3D virtual-world platform, to investigate aspects of technology-enhanced STEM education. These European and USA studies, which differ in their pedagogical-philosophy commitments, theoretical frameworks, methodologies, and target content, critically examine a range of cognitive, affective, technical, and social factors pertaining to the prospects of students' and teachers' successful engagement with immersive microworlds. Specifically, each project describes students' successes and challenges in creating complex virtual artifacts and collaborating in real time with peers and the broader community. The design-based research studies of mathematical and computational literacy present sample student artifacts and discuss the learning they evidence. Collectively, we posit that overcoming the following obstacles could make virtual worlds both effective and exciting learning environments: professional development (technical skill, affective disposition), collaboration with school systems (logistics of access, allocation of resources), alignment with targeted content (harnessing students' creative divergence), and initial learning curves (issues of teacher-to-student ratio).

Abstract
Denotational semantics is a powerful technique to formally de. ne programming languages. However, language constructs are not always orthogonal, so many semantic equations in a definition may have to be aware of unrelated constructs semantics. Current approaches for modularity in this formalism do not address this problem, providing, for this reason, tangled semantic definitions. This paper proposes an incremental approach for denotational semantic specifications, in which each step can either add new features or adapt existing equations, by means of a formal language based on function transformation and aspect weaving.

Abstract
Manufacturing is nowadays facing with markets trends that ask for more customized products, shorter product life-cycles, best quality and shorter prices. Addressing these requirements, manufacturing systems need to be more responsive and reconfigurable, adapting their behaviors to changing conditions. The concepts inherited from biology and nature seem suitable to design reconfigurable manufacturing systems. In this paper, a bio-inspired solution, where self-organization and multi-agent systems play key roles, is described, contributing to achieve an adaptive and evolvable reconfigurable manufacturing control system.

Abstract
In this letter, a novel radio-frequency finite impulse reponse (FIR) electrooptical configuration for self-referencing optical wavelength-division-multiplexed intensity sensors is reported. By employing the proposed low-cost electronic FIR filter at the reception stage, the use of a 14-km fiber delay coil is avoided for a 2-kHz modulation frequency, preserving sensitivity and self-reference. The technique is analyzed following the Z-transform formalism and measurements validating the theoretical model are reported.

Abstract
A seawater quality monitoring program for Foz do Arelho outfall has already started in May 2006 to evaluate the background seawater quality around the vicinity of the sea outfall and to follow the impacts of wastewater discharge in the area. Seven monitoring campaigns were already performed between 2006-2007 in which CTD and ADCP measurements were obtained in the vicinity of the wastewater discharge. Predictions of the plume behavior for several times of the year were obtained using a near field model with the monitoring data as input. The plume behavior was mostly influenced by density stratification. During stratified conditions the plume was trapped with dilutions always above 270 to 1. During unstratified conditions the plume was surfacing with dilutions above always 375 to 1. It is concluded that the outfall is behaving as expected.