Description: In the field of risk evaluation and seismic hazard assessment, it is necessary to codify a great quantity of aspects of the so called knowledge and to supply an intelligent support for the not-well-defined problems (data uncertainty, lack of rigorous solution algorithms). The main feature of an expert system is to emulate effectively the behaviour of a human expert in a particular and defined field, enabling the final user to improve its decisional process and giving access to him to a knowledge base otherwise not clearly codified. From these general considerations the intention came to develop the prototype CZAR (Classificatore Zone A Rischio) that is an expert system reproducing the Italian seismic classification based on the definition of Seismic Hazard given by Progetto Finalizzato Geodinamica (PFG) of the Consiglio Nazionale delle Ricerche (CNR). The expert system built up on the commercial shell Nexpert Object is working on a personal computer through a graphic interface developed with the Graphical User Interface (GUI) of Window 3.0. This user friendly interface makes possible the choice of different procedures to estimate the hazard parameters and also allows the activation of the classification inferential process. The influence of different assumptions and strategies has been evaluated by a mathematical algorithm suggested by the general structure of the Bayes’ theorem. In this paper the prototype of the expert system has been applied to the data relating to Toscana region (central Italy) and the interactive evaluation of the maps furnishes a relative measure for discrepancies on seismic classification in the 2nd seismic category.

Description: Published

Description: 153-173

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: Dispersal and foodweb dynamics have long been studied in separate models. However, over the past decades, it has become abundantly clear that there are intricate interactions between local dynamics and spatial patterns. Trophic meta-communities, i.e. meta-foodwebs, are very complex systems that exhibit complex and often counterintuitive dynamics. Over the past decade, a broad range of modelling approaches have been used to study these systems. In this paper, we review these approaches and the insights that they have revealed. We focus particularly on recent papers that study trophic interactions in spatially extensive settings and highlight the common themes that emerged in different models. There is overwhelming evidence that dispersal (and particularly intermediate levels of dispersal) benefits the maintenance of biodiversity in several different ways. Moreover, some insights have been gained into the effect of different habitat topologies, but these results also show that the exact relationships are much more complex than previously thought, highlighting the need for further research in this area. This article is part of the theme issue ‘Integrative research perspectives on marine conservation’.

Description: The analysis of damage on buildings affected by an earthquake allow to trace back to the defects of the structural system and the imperfections of the constructive elements with reference to the best or worst behaviour in case of seismic action. As a matter of fact the tendency of buildings to be damaged, also defined as seismic vulnerability, is strictly connected with their geometric-constructive characteristics. The damage appears as "effect" of the phenomenon that has its "cause" in the seismic action. Once the characteristics of the system are defined, it is possible to reconstruct the 'cause-effect' relation between seismic action and damage. These relations can be obtained through survey of damage caused by recent earthquake. However this methodology reveals a series of problems. The various quantities applied must be expressed with indices that allow to synthesize complex and articulated scenarios exhaustively; although the damage is a quantity that can be directly assessed by description, it is difficult to measure, as its quantification should be representative for all aspects connected with it (physical, economic, functional, social, etc.). The level of the seismic action must be expressed by a parameter that is an index of the event's destructive capacity and in direct correlation with mechanical quantities (acceleration, velocity, energy, etc.). The vulnerability is an entity able to characterize the more or less accentuated predisposition of the structures to suffer damages independently from the intensity and direction of the seismic action. In this work, subjects concerning seismic action and vulnerability shall not be dealt with, as they have already been investigated in previous works [see Grimaz S., 1992 - Cella F. 1994 and 1995]; in the following the problem of damage quantification shall therefore be explored.

Description: Published

Description: 83-103

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: Whereas the conservation and management of biodiversity has become a key issue in environmental sciences and policy in general, the conservation of marine biodiversity faces additional challenges such as the challenges of accessing field sites (e.g. polar, deep sea), knowledge gaps regarding biodiversity trends, high mobility of many organisms in fluid environments, and ecosystem-specific obstacles to stakeholder engagement and governance. This issue comprises contributions from a diverse international group of scientists in a benchmarking volume for a common research agenda on marine conservation. We begin by addressing information gaps on marine biodiversity trends through novel approaches and technologies, then linking such information to ecosystem functioning through a focus on traits. We then leverage the knowledge of these relationships to inform theory aiming at predicting the future composition and functioning of marine communities. Finally, we elucidate the linkages between marine ecosystems and human societies by examining economic, management and governance approaches that contribute to effective marine conservation in practice. This article is part of the theme issue ‘Integrative research perspectives on marine conservation’.

Description: An accurate identification of species and communities is a prerequisite for analysing and recording biodiversity and community shifts. In the context of marine biodiversity conservation and management, this review outlines past, present and forward-looking perspectives on identifying and recording planktonic diversity by illustrating the transition from traditional species identification based on morphological diagnostic characters to full molecular genetic identification of marine assemblages. In this process, the article presents the methodological advancements by discussing progress and critical aspects of the crossover from traditional to novel and future molecular genetic identifications and it outlines the advantages of integrative approaches using the strengths of both morphological and molecular techniques to identify species and assemblages. We demonstrate this process of identifying and recording marine biodiversity on pelagic copepods as model taxon. Copepods are known for their high taxonomic and ecological diversity and comprise a huge variety of behaviours, forms and life histories, making them a highly interesting and well-studied group in terms of biodiversity and ecosystem functioning. Furthermore, their short life cycles and rapid responses to changing environments make them good indicators and core research components for ecosystem health and status in the light of environmental change. This article is part of the theme issue ‘Integrative research perspectives on marine conservation’.

Description: The studies urban areas directed at the definition of seismic risk, raise the problem of the seismic vulnerability assessment of construction properties that require the estimation of the tendency to damage of a plurality of buildings. Very often one comes upon buildings that have been constructed in former epochs without the use of seismic codes and generally built in masonry. The leads to the search for procedures for vulnerability assessment, based on the rapid acquisition of information on existing buildings, which must furnish a sufficiently reliable assessment of the seismic damageability, generally without the possibility to refer to very sophisticated models. In previous works, assessments of seismic vulnerability have been effected using surveys transferred on National Project for Seismic Prevention (GNDT) sheets (Zonno and Ducarme, eds, 1992). These works have been realized using capes systems in order to treat with the uncertainty of the data. However, the analyses that only refer to GNDT sheets, are limited to single buildings, ideationally understood as isolated. An alternative and maybe complementary attempt is to assess the vulnerability of buildings in a global structural context using Geographic Information Systems to mapping the urban system, integrated with the surveys transferred on COOT sheets. The main characteristics of the building and the structural context, indices of a major or minor damageability, have been individuated, but it is difficult to define a rapid procedure for the assessment of seismic vulnerability. The idea was to use an expert system to codify a basis of the presently acquired knowledge and to apply it automatically on the basis of the results obtained by processes of space analyses calculated by GIS. On the basis of the data obtained with GNDT sheets, the vulnerability of the building can be assessed independently from the structural context (intrinsic vulnerability). The availability of data on the space distribution of the adjoining buildings permits an assessment on the effective vulnerability that takes into account the influence of the structural context. With relation to other works effected on the argument, the proposed system automatically assesses a large quantity of geocoded data either in geometry and in the structure of the components. In particular, in this work the seismic vulnerability assessment of the buildings is effected through the Geographic Information Systems PC Arc-Info connected with the Expert System Shell Nexpert Object, starting from the methods used by the GNDT of the National Council for Research (CNR) (Benedetti and Petrini, 1984; Baldi and Corsanego, 1987) and integrating the effects of anisotropics of the structural behaviour and context (Grimaz, 1992-93).

Description: Published

Description: 105-128

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica