Ana Paula Afonso

Adding Geographic Scopes to Web Resources

Many web pages are rich in geographic information and primarily relevant to geographically limited communities. However, existing IR systems only recently began to offer local services and largely ignore geo-spatial information. This paper presents our work on automatically identifying the geographical scope of web documents, which provides the means to develop retrieval tools that take the geographical context into consideration. Our approach makes extensive use of an ontology of geographical concepts, and includes a system architecture for extracting geographic information from large collections of web documents. The proposed method involves recognising geographical references over the documents and assigning geographical scopes through a graph ranking algorithm. Initial evaluation results are encouraging, indicating the viability of this approach.

Evaluation of Overcluttering Prevention Techniques for Mobile Devices

The increasing popularity of mobile devices has fostered the development of visualization applications for these devices. However, the reduced screen size and different interaction devices, which people are not familiarized, present some challenges to visualization in a mobile environment. This paper describes how, as a proof of concept, a combination of two different techniques can reduce the over cluttering of icons on a mobile device screen. An evaluation of these techniques is also presented.

The nature of Hα star-forming galaxies at z∼ 0.4 in and around Cl 0939+4713: the environment matters

Cluster star-forming galaxies are found to have an excess of far-infrared emission relative to Hα, when compared to those in the field, which could be caused by intense active galactic nuclei (AGN) activity, dust and/or declining star formation histories. Here we present spectroscopic observations of Hα emitters in the Cl 0939+4713 (Abell 851) super-cluster at z = 0.41, using AF2+ WYFFOS on the William Herschel Telescope. We measure [O ii], Hβ, [O iii], Hα and [N ii] for a sample of 119 Hα emitters in and around the cluster. We find that 17 ± 5 per cent of the Hα emitters are AGN, irrespective of environment. For star-forming galaxies, we obtain Balmer decrements, metallicities and ionization parameters with different methods, individually and by stacking. We find a strong mass–metallicity relation at all environments, with no significant dependence on environment. The ionization parameter declines with increasing stellar mass for low-mass galaxies. Hα emitters residing in intermediate environments show the highest ionization parameters (along with high [O iii]/Hα and high [O iii]/[O ii] line ratios, typically twice as large as in the highest and lowest densities), which decline with increasing environmental density. Dust extinction (A_(Hα)) correlates strongly with stellar mass, but also with environmental density. Star-forming galaxies in the densest environments are found to be significantly dustier (A_(Hα) ≈ 1.5 − 1.6) than those residing in the lowest density environments (A_(Hα) ≈ 0.6), deviating significantly from what would be predicted given their stellar masses.

Visualization of geographic query results for small screen devices

The visualization of geo-referenced information on a map has become an essential method to help the users to get the intended information. The adaptation of visualization techniques for mobile devices, such as, PDA and mobile phones make this type of applications ubiquitous. However, the context of mobility and the limitations of mobile devices, such as, the small screen, suggest that some visualization techniques may not be appropriate for those devices. In this work we intend to integrate filtering mechanisms, based on semantic criteria, and to use multiple representations with different levels of detail to generate intelligible representations as a result of geographic queries in mobile environments.

MoViSys --- A Visualization System for Geo-Referenced Information on Mobile Devices

Visualization of geo-referenced information on mobile devices can be useful in diverse areas. These applications require a user-friendly interface to enable querying the data interactively and the generation of intelligible images. Moreover, they must deal with the limitations of mobile devices, such as small screen size, and the context of mobility. This paper describes MoViSys, a visualization system for geo-referenced data, organized in several categories with multiple attributes, on mobile devices. This system explores filtering mechanisms to present the result of interactive queries specified through an adaptive interface.

Filtering mechanisms for the visualization of geo-referenced information

This paper describes a prototype of a web tool for the visualization of geo-referenced information organized in several categories. The main features that distinguish this tool from others with the same purpose are the inclusion of filtering mechanisms based on semantic criteria and the use of multiple representations with different levels of detail. Filtering mechanisms contribute to reduce the amount of displayed data allowing the generation of intelligible representations. The user selects interactively the categories she/he is interested in. This is a basic filtering mechanism, but besides this, a degree of interest function is used to include semantic criteria. This function quantifies the users interest in order to visualize the most relevant data, suppressing the less relevant data.The definition of multiple representations with different levels of detail enables the reduction of the detail when small scales are being used. In addition less detailed representations are used to present less relevant data.

Dynamic Information Dissemination to Mobile Users

We present the dynamic channel model, an information push model for data dissemination to mobile users. This is a set of extensions to the conceptual models developed for information channels that capture mobility-specific requirements. Dynamic channels are used for filtering and setting update order priorities for the information that users intend to monitor, which depends on their location and changes as they roam. The dynamic channel model was implemented in Ubidata, a software framework for the construction of systems for information dissemination to mobile users.

Designing Information Appliances Using a Resource Replication Model

We discuss the design of new network applications that collect and manage data and interface with users through portable devices. These applications maintain data pipelines that interact with network information servers and distill information into reduced data models that may be queried and replicated effectively through wireless networks to computing devices of very small size. We present initial design considerations for applications of this class.

Dynamic data delivery to mobile users

We propose an information push model information dissemination to mobile users, called dynamic channel model. It is a set of extensions to the conceptual models developed for information channels, capturing mobility-specific requirements. These are used for filtering and setting update order priorities for the information that users intend to monitor, which depends on their location and changes as they roam. We also present the architecture of Ubidata, an adaptable framework for information dissemination to mobile systems. We introduce our development process for a class of mobile computing applications operating under an information dissemination metaphor.

Context aware point of interest adaptive recommendation

Applications that allow the users to search for nearby points of interest have, recently, become very popular amongst mobile device users. However, the increasing amount of available information and the limitations of current mobile devices can hinder an efficient and helpful user experience. It is fundamental that what is shown to the user is relevant. We propose an adaptive recommendation function that uses location and temporal contexts combined with the historical context of the previous searches to quantify the relevance of the points of interest shown to the user.