The proliferation of mobile devices and the emergence of wireless location-based services has generated consumer demand for availability of GPS in urban and indoor environments. This demand calls for enhanced GPS algorithms that accommodate high degrees of signal attenuation and multipath effects unique to the ''urban channel.'' This paper overviews the market for location-based services and discusses algorithmic innovations that address challenges posed by urban environments.

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Lake Trasimeno is a closed lake in Central Italy and in historically its water level has been affected by wide fluctuations mostly depending on the climate. The lake has suffered many water crises due to water scarcity and in recent decades, droughts have also severely affected the economic and environmental situation. The aim of this study was to analyze the possibility of limiting these severe level fluctuations by evaluating of feasible water resource management policies that could also reduce the environmental stress of this area. Therefore, a specific decision support system (DSS) has been developed in order to simulate different scenarios for the entire water system of the Trasimeno area. In particular, the hydrological model implemented in the DSS allowed for the simulation and validation of different management policy hypotheses for the water resource in order to mitigate environmental and water crises for the Lake Trasimeno. Results indicated that it is possible to transfer a certain amount of water from nearby reservoirs without affecting the availability of the resource for specific users. In this way, Lake Trasimeno can benefit both from an increase in water levels in the lake, so a possible better situation in quantitatively and qualitatively.

This paper discusses various methods for calculating the minimum instream flows for the protection of aquatic life for the purpose of illustrating its increasing complexity. These procedures are the Montana method (Tennant, 1976); the wetted perimeter method (Collings, 1974; Cochnauer, 1976) and the IFIM method (Instream Flow Incremental Methodology; Bovee, 1982). An analysis is then made of some regionalisation criteria based on these methods, from which useful suggestions can be drawn for the development of a procedure to be applied to basins. A method is thus proposed for calculating the recommended flows for protecting the aquatic environment based on simple hydrological variables, such as Q7 10, which can be estimated for a basin on the basis of area A and a Base Flow Index (BFI) which summarises its hydrogeological characteristics. This approach can be used when the field data necessary for more complex methods is not available. These require the defining of the environmental suitability of a watercourse for certain designated reference fish species, according to the flow and the morphology of the channel. The positive results of this approach were verified by Leonard (1990) and this methodology was applied to the Tiber river basin.