Location-based indexing for mobile context-aware access to a digital library

Mobile information systems need to collaborate with each other to provide seamless information access to the user. Information about the user and their context provides the points of contact between the systems. Location is the most basic user context. TIP is a mobile tourist information system that provides location-based access to documents in the digital library Greenstone. This paper identifies the challenges for providing effcient access to location-based information using the various access modes a tourist requires on their travels. We discuss our extended 2DR-tree approach to meet these challenges

Spatial distribution of land type in regression models of pollutant loading

This paper proposes a method to improve landscape-pollution interaction regression models through the inclusion of a variable that describes the spatial distribution of a land type with respect to the pattern of runoff within a drainage catchment. The proposed index is used as an independent variable to enhance the strength, as quantified by R² values, of regression relationships between empirical observations of in-stream pollutant concentrations and land type by considering the spatial distribution of key land-type categories within the sample point’s drainage area. We present an index that adds a new dimension of explanatory power when used in conjunction with a variable describing the proportion of the land type. We demonstrate the usefulness of this index by exploring the relationship between nitrate ( - 3 NO ) and land type within 40 drainage sub-catchments in the Ipswich River watershed, Massachusetts. Nutrient loads associated with non-point source pollution paths are related to land type within the up-stream drainage catchments of sample sites. Past studies have focused on the quantity of particular land type within a sample point’s drainage catchment. Quantifying the spatial distribution of key land-type categories in terms of location on a runoff surface can improve our understanding of the relationship between sampled - 3 NO concentrations and land type. Regressions that employ the proportion of residential and agricultural land type within catchments provide a fair fit (R² = 0.67). However, we find that a regression adding a variable that indicates the spatial distribution of residential land improves the overall relationship between instream - 3 NO measurements and associated land types (R² = 0.712). We test the sensitivity of the results with respect to variations in the surface definition in order to determine the conditions under which the spatial index variable is useful

Sistema Integrado de Informação de apoio à investigação de técnicas de mitigação da erosão dos solos na sequência de incêndios florestais

The project RECOVER aims to develop mitigation techniques to reduce soil and water degradation immediately after forest fires. Forest fires are becoming increasingly frequent as a result of climate change and poor forest planning, with deleterious impacts on soil fertility and structure. It erodes the top soil layers, where is located the only nutrient pool of the majority of Portuguese soils. This nutrient mobilization happens during the first autumn rainfall events, and therefore sediment and nutrient exportation typically occurs in the first 4/6 months after fire. The speed at which nutrient loss occurs and the extension of forest fires limits in terms of costs and logistics the solutions that can be taken to reduce soil and water degradation. RECOVER will test a set of feasible solutions to reduce ash flush. This is essential to produce feasible solutions that will be easily adopted by forest managers and forest owners. RECOVER presents an innovative approach based on field surveys of soil and vegetation properties following forest fires, which will be used to perform a GIS database from which the critical spots will be identified. The implementation of an integrated information system (integrating a spatial database, a map server and GIS software) will allow us to store the data collected in the field as well as the information produced through the spatial analysis. This information will be available in a web‐GIS portal, complemented with information to producers and all other agents evolved in the forestry management.O RECOVER almeja desenvolver técnicas mitigadoras e estratégias para a redução da degradação do solo e da água imediatamente após os incêndios florestais. A frequência dos referidos incêndios florestais tem vindo a aumentar, fruto das mudanças climáticas e do deficiente planeamento florestal, com severos impactes ao nível da fertilidade e estrutura dos solos. Como consequência aumenta a erosão da camada superior dos solos, onde se localizam, na maioria dos solos portugueses, os únicos nutrientes existentes. Esta mobilização de nutrientes ocorre nos primeiros eventos chuvosos outonais, e, como tal, a exportação dos sedimentos e dos nutrientes acontece normalmente nos primeiros 4/6 meses após os incêndios. A velocidade a que a perda de cada nutriente ocorre e a extensão dos incêndios florestais é uma condicionante em termos de custos e baliza as soluções que se podem implementar para a redução da degradação do solo e da água. O RECOVER testará um conjunto de soluções praticáveis de forma a reduzir a lavagem das cinzas. A metodologia proposta apresenta uma integração inovadora de técnicas quantitativas de campo e irá proceder a análises de percepção junto de todos os intervenientes no planeamento florestal. Tal abordagem é essencial afim de produzir soluções passíveis de se colocar em prática que poderão ser facilmente adoptadas pelos planeadores florestais bem como pelos proprietários florestais. Este projecto apresenta uma abordagem inovadora baseada em levantamentos de campo das propriedades do solo e da vegetação após a ocorrência de incêndios florestais, cujos resultados serão usados para a construção de uma base de dados em ambiente SIG, que servirá para identificar os locais críticos. A implementação de um sistema de informação integrado (conjugando uma base de dados espacial, um servidor de mapas e software SIG) permitir‐nos‐á armazenar os dados recolhidos no campo bem como a informação produzida através da análise espacial desenvolvida. Esta informação estará disponível através de um portal Web‐SIG, complementado com informações para os produtores e todos os outros agentes envolvidos na gestão florestal