The ubiquity of low-cost GPS-enabled mobile devices and the proliferation of online social networks have enabled the collection of rich geo-social information that includes the whereabouts of the users and their social connections. This information can be used to provide a rich set of access control policies that ensure that resources are utilized uniquely and securely. Existing literature focu...

Combined processing using different sensor types, i.e. for applications like change detection, requires a good geo-referencing. Furthermore the individual sensor properties have to be taken into account. SAR systems are side-looking and run-time systems. They suffer from occlusions and ambiguities especially in urban areas. Additionally layover and shadow effects disturb the geo-referencing of ...

Interoperability is a crucial problem for geographic information systems. The transfer of data and models between different systems requires the ability to set up a correspondence between concepts in one system to concepts in the other. Concept matching is helped by ontologies. However, the challenge of making ontologies themselves interoperable continues. In other words, given two geo-ontologi...

P ropelling aerosols into the upper atmosphere or pumping carbon dioxide into the deep ocean are just two schemes that have been proposed to repair the Earth’s climate through geo-engineering1 (see Box 1). In the absence of adequate reductions in anthropogenic CO2 emissions, geo-engineering has been put forward as the only remaining option that might fix our rapidly changing climate2. Because s...

Data security in a mobile context is a critical issue. Over the last few years a new category of location-based services, the Enterprise LBS (ELBS), has emerged focusing on the demands of mobility in organisations. These applications pose challenging requirements, including the need of selective access to ELBS based on the position of mobile users and spatially bounded organisational roles. To ...

Geographic Information Retrieval (GIR) in an attempt to improve relevance by taking geographic information in textual documents into account. We describe out experiments carried out at the GeoCLEF 2007 evaluation [1] that investigate further the role of geo-filtering based re-ranking and query expansion with geographic terms. Our main findings are that manual query expansion with geo-terms is m...

Due to limited receiver bandwidth and tracking configuration differences, measurements made on a narrowband geostationary satellite signal may differ significantly from those made on GPS signals and result in relatively large range bias errors for users. Modeling and analysis of this net effect is complicated by several parameters including a wide range of allowed GEO signal correlator spacings...

Distal lung development occurs through coordinated induction of myofibroblasts, epithelial cells, and capillaries. Lunatic Fringe (Lfng) is a beta(1-3) N-acetylglucosamine transferase that modifies Notch receptors to facilitate their activation by Delta-like (Dll1/4) ligands. Lfng is expressed in the distal lung during saccular development, and deletion of this gene impairs myofibroblast differ...

Many social media researchers and data scientists collected geotagged tweets to conduct spatial analysis or identify spatiotemporal patterns of filtered messages for specific topics or events. This paper provides a systematic view to illustrate the characteristics (data noises, user biases, and system errors) of geo-tagged tweets from the Twitter Streaming API. First, we found that a small perc...