P. Mazzetti

Integration of REST style and AJAX technologies to build Web applications; an example of framework for Location-Based-Services

In the last years two important architectural and technological solutions have been proposed for improving Web applications design. The REST architectural style has been defined to describe the WWW architecture and to guide its future evolution preserving the fundamental characteristics of scalability. At the same time AJAX and related technologies have changed the way many Web applications are designed and implemented enhancing responsiveness and pervasiveness. The integration of this two approaches seems promising, but several issues must be tackled. For testing possible solutions, we designed and implemented a framework for building mobile Web applications using the REST architecture and AJAX technologies: the MIRAJ framework. It was used to develop a basic set of Location-Based-Services for tourist guidance in an archaeological park located in Metaponto, Italy.

Interoperability federated system for the scientific community working in the EOS sector

A federation system solution suited for the challenging area of the Earth Observation from Space (EOS) domain is presented. It addresses system integration issues, conceiving a distributed system based on modern industry-standard protocols, whose components are existing legacy systems. A web-enabled federation system-a distributed system which implements a loosely-coupled federated database system-was designed and developed. The interoperability issue was tackled by a couple of solutions: a mediated message-based architecture and the specification of a federation common model. Several e-business enabling technologies were utilised for achieving the system reusable components, in particular XML-based ones. An application scenario, experimented in the framework of a project funded by the Italian Space Agency (ASI) is briefly reported.

Case-study on the use of microwave sensors for cloud detection over Tuscany

The present work empirically deals with the challenging problem of the integration of data obtained from passive and active microwave sources, in order to develop procedures to suitably calibrate and validate satellite-based passive microwave rainfall algorithms by means of multiparameter radar information over midlatitude areas. In particular it addresses the problems due to the time interval between radar and radiometer acquisitions and to the different view geometry of the sensors. A statistical image processing technique is utilised in order to navigate data, reducing effects due to cloud shape change and motion during the time lag. Results show that time lag and geometry differences effects reduction can significantly improve correlation allowing to better investigate the inner cloud structure.

Design and implementation of wireless tourist services in the Metaponto archaeological park

The paper describes the services implementation starting from the system architecture definition to the deployment, analyzing the design solutions and technological choices. As a result of user analysis, two services W-park and W-site are used for testing. The Metaponto archaeological park was considered as a good choice for the demonstration of these two services, which are designed to provide guidance and special information of large areas such as natural and archaeological parks. Thus the design and development of W-park and W-site services showed the importance of high-level design to integrate innovative technologies in the existing frameworks to build new services.

SSM/I and the Montagnana radar data fusion to analyze clouds over Tuscany

The present work empirically deals with the challenging problem of the integration of data obtained from passive and active microwave sources, in order to develop procedures to suitably calibrate and validate satellite-based passive microwave rainfall algorithms by means of multi parameter radar information over midlatitude areas. Furthermore, this research tires to analyze the well-known beam-filling problem and the different microwave channel penetration top9ic. SSM/I passive microwave radiometer precipitation related parameters were analyzed against multi parameter radar Zh and Zdr 3D maps, obtained from the POLAR-55C multi parameter radar set near Florence, Italy. SSM/I-derived parameters, related to rainfall over land were analyzed by means of information derived form radar volume data. We faced several statistical analyses of the obtained data sets. Results report the effectiveness of Montagnana radar and SSM/I data fusion. In particular, it is assessed the utility of utilizing both active and passive microwave hydrometeor-related information in order to improve the inferences about monitored phenomena. Results are valuable in order to better calibrate and validate passive microwave algorithms for rainfall rate estimation and for cloud detection over land. Correlation values may be improved by filtering radar data according to several parameters thresholds, in order to tackle beam-filling problem and statistical issues.

Microwave rainfall monitoring: a Tuscany study case

The present work empirically deals with the challenging problem of the integration of data obtained from passive and active microwave sources, in order to develop procedures to suitably calibrate and validate satellite-based passive microwave rainfall algorithms by means of near simultaneous multi-parameter radar information acquired over the same area. SSM/I passive microwave radiometer precipitation related parameters have been compared with multi-parameter radar Zh and Zdr constant-altitude and vertical profile maps, obtained from CAPPI and RHI data from the POLAR-55C meteorological radar, located near Florence in Italy. As a result, such investigation proved the importance of considering the different vertical penetrations due to the diverse microwave channels, in order to work out better regression laws between the passive and active data.

Improving rainfall estimates derived from dual polarization C-band radar reflectivity data

Abstract Attenuation due to propagation is a significant problem for weather radars operating in C-band or at higher frequencies. When an accurate rainfall rate estimate is required, as in hydrological applications, a good attenuation correction technique must be carefully applied. The task becomes more complex when only incoherent radar observables are available (absolute and differential reflectivity ZH and ZDR): in such a case, standard cumulative algorithms for attenuation correction are commonly used on a range cell by range cell basis. However, instabilities show up in the presence of anomalous reflectivity data and can diverge, leading to unrealistic rainfall rates. To avoid the correction become useless or even void of sense, it must be applied on data that have been previously corrected from other sources of errors. The major causes of anomalous reflectivity are related to beam blocking effects and related clutter phenomena, common in regions with a complex orography. Here we analyze on experimental data the advantages obtained by accounting for clutter and screening effects, before correcting attenuation due to propagation. Results show that the preliminary correction of radar data can help to reduce instabilities and to obtain better rainfall rate estimates when compared to raingage data. Some residual instability may show up in some cases, due to the inadequacy of the reflectivity-attenuation relationships at high reflectivity values.

Active and passive microwave for rainfall monitoring

This paper reports the experimentation of a joint use of ground-based radars and satellite radiometer in order to obtain more information at diverse spatial and temporal scales to improve quantitative measurement of rainfall over the centre of Italy. In particular the utilisation of radar vertical profile measurements to validate and calibrate passive microwave data is outlined. Experimentation has been conducted on a data set made up of Montagnana multiparameter C-band and DMSP-SSM/I data.

Robustness and limitation of algorithms for attenuation correction of C-band meteorological radar

Addresses the problem of jointly correcting beam blocking and C-band propagation attenuation effects in weather radars by resorting to incoherent radar observables and to a clutter discrimination technique. The authors propose a strategy for data processing and discuss its effectiveness based on data gathered during a severe storm occurred in October 1992. Data analysis points out that accounting for the effects of clutter contamination and beam screening in the correction procedure greatly helps in mitigating the effects the instability of iterative techniques utilised for C-band attenuation correction. Nevertheless, in the presence of extremely intense rainfall, the correction algorithm may still. Diverge, clearly evidencing that in such cases the problem of an adequate and careful criterion to derive the specific attenuation-reflectivity conversion relationship becomes of primary importance.

Spatial and temporal sampling errors in rainfall fields reconstruction through meteorological radar data

The accuracy in the reconstruction of space-time rainfall fields through radar rainfall estimates depends both on the accuracy of the estimate in the radar sample volume, and on the data updating capability of the radar system. The last aspect becomes of capital importance when the monitored phenomenon exhibits a high variability both in space and in time. This paper analyzes the problem of the optimal choice, depending on monitored event, of parameters of the radar acquisition, to minimize the error in reconstructing a rainfall field through the radar observation.<<ETX>>