Abstract
Nowadays, there is a wide range of commercial LBMS (Location-Based Mobile Services) available in the market, and a trend towards the display of 3D maps can be clearly observed. Given the complete disparity of ideas and a visible commercial orientation in the industry, the study of the visualization aspects that influence user performance and experience in the exploration of urban environments, using 3D maps, becomes an important issue. Based on a proposed conceptual framework, an online questionnaire was developed and administered in order to measure the real impact of each element. Combining the experimental results with the current state-of-the-art, a new visualization paradigm is defined in a dual specification: "layers" providing relevant visual content to the map, and "functions" providing the necessary functionality.

Abstract
We describe a real-time facade tracking system that uses, as setup information, only two images of a facade, captured on the moment. No more previous information is needed, such as a facade 3D model, dimensions or aspect ratio. Feature points and their local descriptors are extracted from that pair of images and used during the detection and tracking of the facade. Additionally, parallax and topological information is also used in order to increase the overall robustness of the tracking process. Experiments show that the system can detect and track a wide variety of facades, including those that are not entirely planar, partially occluded or have few distinguishable visual landmarks. The reliance on on-the-spot information, alone, makes this system useful for Outdoor Augmented Reality applications, in an Anywhere Augmentation urban context.

Abstract
There are several problems in the computer graphics and visualization domains which require optimization tasks to be performed in order to improve the quality of the overall process. In this context, we propose and describe an innovative optimization methodology and a supporting software framework: i-om. The design goals of the proposed framework were twofold. The first comprises the decoupling, as much as possible, of the optimization process from the application specific processing tasks. In order to attain this goal, we opted to make use of intelligent techniques (i.e. metaheuristics). The second goal is to allow remote operation, and consequently great portability and interoperability, between the optimization tools and the visualization application. To fulfill the latter requirement the proposed framework was designed with the ability to communicate with external application using a specifically developed high level message protocol. The optimization framework was implemented and the paper presents illustrative results demonstrating the usefulness and effectiveness of the proposed approach..

Abstract
Documents on the World Wide Web are dynamic entities. Mainstream information retrieval systems and techniques are primarily focused on the latest version a document, generally ignoring its evolution over time. In this work, we study the term frequency dynamics in web documents over their lifespan. We use the Wikipedia as a document collection because it is a broad and public resource and, more important, because it provides access to the complete revision history of each document. We investigate the progression of similarity values over two projection variables, namely revision order and revision date. Based on this investigation we find that term frequency in encyclopedic documents - i.e. comprehensive and focused on a single topic - exhibits a rapid and steady progression towards the document's current version. The content in early versions quickly becomes very similar to the present version of the document.

Abstract
Strategies developed for database preservation in the past include technology preservation, migration, emulation and the use of a universal virtual computer. In this paper we present a new concept of "Model Migration for Database Preservation". Our proposed approach involves two major activities. First, migrating the database model from conventional relational model to dimensional model and second, calculating the information embedded in code and preserving it instead of preserving the code required to calculate it. This will affect the originality of the database but improve two other characteristics: the information considered relevant is kept in a simple and easier to understand format and the systematic process to preserve the dimensional model is independent of the DBMS details and application logic.

Abstract
The study of the blogosphere can provide sociologically relevant data. We analyze the links between blogs in the portuguese blogosphere, in order to understand how they group and interact, to identify clusters and to characterize them. Our data set contains post data for more than 70,000 blogs, with over 400,000 links. The linkage data is represented as a blog graph and partitioned into several slices, according to their in-degree. We then study the evolution of blog features, and observe a consistent pattern of decrease in posting frequency, number of out-links, and post length, as we move from the highly-cited blogs to the less cited ones. Copyright 2010 ACM.