Abstract
This paper describes an interferometric synthetic aperture sonar system based on an unmanned surface vehicle customized for shallow water environments. Synthetic aperture sonar enables imagery of high resolution that is independent of range by using the displacement of the sonar platform to create a large virtual array. If two geometrically displaced images are obtained, the construction of three-dimensional topographic maps is possible through the use of interferometric techniques. The use of an unmanned surface vehicle presents several advantages that alleviate some problems related to the formation of synthetic aperture images, which are mainly related to the fact that a precise navigation system can be used for the boat control and sonar imagery motion compensation. Also, a small unmanned surface vehicle is advantageous in terms of cost of operation, maintenance and ease of deployment. Mapping of shallow water areas is an important task for many commercial and scientific applications like river navigability, infrastructure maintenance and natural resource monitoring. These tasks can be done efficiently with this system. Sample data obtained during test trials illustrate how synthetic aperture can be used to generate underwater imagery and bathymetric data.

Abstract
This study is dedicated to the learning process to help students to deal with the complexity of a Lighting Design Project. In the Department of Electrical Engineering, preference was given to applying methods integrating technology in the learning and then evaluating the outcomes. Problem-based learning (PBL) was used as an instructional strategy of active learning, and adapted for use in Lighting Design course. In cooperative learning, students work together in small groups in an organized way, on a well-ordered activity They are individually responsible for their work,. on the other hand, the work of the group as a whole is also assessed. Teams need to be small enough so that everyone can play apart And the students' work must be clearly defined. By applying PBL it is expected that students work in a cooperative and collaborative learning way, developing positive interdependence, individual accountability, face-to-face promotive interaction, as well as group processing. Students see the potential of the method. PBL addresses many of the concerns of teachers and professional organizations. Above all, it encourages students to be in charge of their education. It emphasizes critical thinking skills, understanding, learning how to learn, and working cooperatively with others. The benefits of PBL in the Lighting Design course are seen in the way students improved the study and analysis of a Lighting Design project. This method can also he seen as a benefit for Electrical Engineering programme where educators strive for improved teaching and learning.

Abstract
Besides services traditionally available in wireless networks, new ones may be offered that transparently adjust and adapt to the user context. The user would have more choice and flexibility if not only could he use platform and third-party services, but also compose his own services in an ad-hoc way, making it available to other users, involving them collaboratively in the construction of a wide set of services. Moreover, collaboration among users can be fostered by the availability of awareness services in mobile environments that enable them to execute joint tasks and activities. This paper presents iCas, an architecture to create context-aware services on the fly, and discusses its main modules. Also a collaborative application scenario is briefly described.

Abstract
The primary goal of the research on image segmentation is to produce better segmentation algorithms. In spite of almost 50 years of research and development in this Held, the general problem of splitting in image into meaningful regions remains unsolved. New and emerging techniques are constantly being applied with reduced Success. The design of each of these new segmentation algorithms requires spending careful attention judging the effectiveness of the technique. This paper demonstrates how the proposed methodology is well suited to perform a quantitative comparison between image segmentation algorithms using I ground-truth segmentation. It consists of a general framework already partially proposed in the literature, but dispersed over several works. The framework is based on the principle of eliminating the minimum number of elements Such that a specified condition is met. This rule translates directly into a global optimization procedure and the intersection-graph between two partitions emerges as the natural tool to solve it. The objective of this paper is to summarize, aggregate and extend the dispersed work. The principle is clarified, presented striped of unnecessary supports and extended to sequences of images. Our Study shows that the proposed framework for segmentation performance evaluation is simple, general and mathematically sound.

Abstract
Web search engines are powerful tools used to satisfy specific information needs on the web. Their purpose is to maximize user satisfaction when performing this task. Although there are other sources of evidence, besides text, to characterize document relevance for a specific need, especially for HTML documents, current search engines do not allow users to explore these features when posing a query. Search engine queries are based almost exclusively on keywords. We believe that it is possible to improve user satisfaction if HTML tags and document metadata are available to users at query time. In this paper we present Xearch, a meta-search system that wraps public search engines in a framework that improves both the expressiveness of the language available for the user to specify information needs and the control over the answer format. Xearch converts HTML pages to a specific XML Schema, covering text and metadata derived from HTML. User queries are then submitted on this schema and can be specified through keywords but also explore documents' HTML tags and metadata. Results from our experimental evaluation confirm that it is possible to improve the answer quality with this framework.

Abstract
The ability to interactively render dynamic scenes with global illumination is one of the main challenges in computer graphics. The improvement in performance of interactive ray tracing brought about by significant advances in hardware and careful exploitation of coherence has rendered the potential of interactive global illumination a reality. However, the simulation of complex light transport phenomena, such as diffuse interreflections, is still quite costly to compute in real time. In this paper we present a caching scheme, termed Instant Caching, based on a combination of irradiance caching and instant radiosity. By reutilising calculations from neighbouring computations this results in a speedup over previous instant radiosity-based approaches. Additionally, temporal coherence is exploited by identifying which computations have been invalidated due to geometric transformations and updating only those paths. The exploitation of spatial and temporal coherence allows us to achieve superior frame rates for interactive global illumination within dynamic scenes, without any precomputation or quality loss when compared to previous methods; handling of lighting and material changes are also demonstrated.