3-D GPR survey with a modular system: reducing positioning inaccuracies and linear noise

Recently, the use of ground-penetrating radar (GPR) arrays with a large number of antenna elements in a fixed configuration has become more common. The investment needed for these systems is significant. Although gradually expandable modular systems, consisting of antennas which can be used independently, do not match the fast acquisition of detailed datasets by means of multi-channel arrays, they can help finding a compromise between increased acquisition speed and (limited) resources. In modular systems, the separation between transmitter-receiver pairs is often larger than the sampling distance prescribed by the Nyquist theorem. As a consequence, additional profiles have to be recorded in between, which requires a high positioning precision. As a completely identical response for the different antennas in an array is difficult to achieve, stripes can occur in the horizontal slices, especially when ringing occurs. This complicates the interpretation of features in the direction of the survey lines. In this paper, a three-dimensional frequency-wavenumber filter is proposed, consisting in a combination of a circular filter and a fan filter. The application of this filter to GPR data collected at the Roman town Mariana (Corsica, France) showed a reduction of the stripe patterns, allowing a more reliable characterization of subtle archaeological structures

Integration of survey, excavation and historical data in Northern Picenum

In this paper it is argued that an integrated non-invasive survey approach, with a large contribution of aerial photography and remote sensing operations, is one of the best ways to achieve diachronic site characterisation and typology of Roman settlements during some of their stages, without having to fall back on large scale and expensive excavation work. Thanks to such an approach, preferably applied on partially or completely deserted sites and areas with a high potential for surface reconnaissance, we are in the position to look not only at such important matters as size and shape, but also at function and functional zoning. Interesting aspects about functional zoning that can be studied thanks to this particular intra-site approach are: discontinuity in the use of space, fluctuations in the size of the built-up area and gradual shifts in the location of the nuclei of the settlement sites. Field survey experience in the Italian landcape has demonstrated that intensive and repeated artefact survey combined with geomorphological operations, geophysical prospections, and systematically checked and monitored by aerial reconnaissance and (if available) compared with regionally or locally available stratigraphic data, is one of the best approaches to detect all three of these dimensions of change. To demonstrate the possibilities of such an integrated approach a case study from Central-Adriatic Italy is chosen. Selected results are presented of systematic archaeological survey work, carried out since 2000 in Northern Picenum (Le Marche) in particular around the coastal Roman town of Potentia and the inland cities of Trea, Ricina and Septempeda

Scanning and visualization of Roman Adriatic townscapes

Since 2000 a team from Ghent University has achieved intensive non-invasive intra-site prospections on four abandoned Roman towns in central Adriatic Italy (Marche Region): the coastal colony of Potentia and the inland municipia of Ricina, Trea and Septempeda. These urban surveys include total coverage geophysical prospections (such as GPR, geomagnetic and earth resistance approaches), low altitude aerial photography (including NIR photography with drone and helikite), geomorphological augerings, surface artifact collection, and micro-topographical field measurements. A GIS-based integration of all survey data, maps and re-studied legacy data has procured a formidable database for the computer-aided digital 3D mapping and interpretation of these complex ancient sites. The methodological acquisitions and archaeological results not only contribute to the understanding of Roman urbanization in this part of Italy, but also support and innovate the use of integrated approaches to geospatial mapping and analysis of ancient urban environments. Based on earlier experiences with 3D visualizations of the abandoned Roman town of Ammaia in Lusitania, as part of the EC funded Project ‘Radiography of the Past’ (http://www2.radiopast.eu/), the project in Adriatic Italy moves now towards presenting the new data in digital formats that allow specialists from archaeology and cultural heritage management, as well as the wider public to immerse into the visual world of Roman Late Republican and Imperial townscapes of a whole valley and its coastal environment

Investment and monetary policy in the euro area

This paper analyses the effects of a change in monetary policy on firms' investment in Germany, France, Italy and Spain using a data set which provides aggregated balance sheet and profit and loss account data for 17 different industries and 3 different size classes. The main findings are twofold. First, in each of the four countries a change in the user cost of capital, which in turn is affected by interest rates, has both statistically and economically significant effects on investment. Second, while the average interest rate on debt is generally higher for small firms than for large firms, there is little evidence that the effects of monetary policy on small firms are larger JEL Classification: E52

Urban landscape survey in Italy and the Mediterranean

Field survey has been making a major contribution to our understanding of the rural landscapes of the Mediterranean for nearly forty years. During that time the techniques used to map ancient settlement patterns have grown in sophistication from being a process of simply identifying sites in the landscape, to one which provided nuanced understandings of their layouts, chronologies and contexts. This has led to a revolution in how archaeologists approach urban sites, with survey techniques being used increasingly often to generate a plan of a town site prior to excavation as a way of ensuring that the excavation can be used to address site-specific questions in a way that had not been possible before. Most recently, research has begun to reveal the advantages of integrating a range of different non-destructive techniques on urban sites. In combination with exciting new computer-based means of data visualization, all of this work means that it is now possible to virtually reconstruct a buried town within a relatively short space of time, as opposed to the old and destructive excavation-centered approach that could take generations. Unsurprisingly these advances are starting to make a very important understanding to urbanism in general and the Roman Empire in particular. Urban Landscape Survey in Italy and the Mediterranean builds upon all these new developments and is one of the first publications to focus exclusively upon the contribution of survey techniques to our understanding of ancient towns. It addresses methodology led enquiry into the nature of urban settlements primarily in Italy, but also in Greece, Turkey, Croatia, Portugal and Spain. The twenty-two papers from leading specialists in the field focus on two underlying themes. The first deals with the characterization of urban sites and draws upon a wide range of case studies. These range from key protohistoric centres in central and south Italy, to towns that epitomise the contradictions of cultural change under Rome, such as Paestum, Aquinum and Sagalassos, to Roman centres such as Teano, Suasa and Ammaia. The second theme is inter-urban relationships, looking in particular at wider urbanized landscapes in Italy. The fascinating selection of recent and on-going projects presented here significantly moves the limits of our current knowledge about ancient towns