Gregorio D’Agostino

Atomic simulation of a palladium nanophase

Abstract The present paper is aimed at introducing various methods for simulating nanophase materials at the atomic level. Palladium is assumed as a prototype of a large class of materials. Thermodynamic, structural and mechanical properties have been computed and compared with the bulk ones in order to outline possible peculiarities of the simulated nanostructures. The role of the density as a critical parameter to classify the simulated samples have also been emphasized. Structural analysis have been performed by means of Voronoi-like polyhedra which also provide the localization of the disorder. Finally simulated cold compactification and heating process have been performed.

When a text is translated does the complexity of its vocabulary change? Translations and target readerships.

In linguistic studies, the academic level of the vocabulary in a text can be described in terms of statistical physics by using a “temperature” concept related to the texts word-frequency distribution. We propose a “comparative thermo-linguistic” technique to analyze the vocabulary of a text to determine its academic level and its target readership in any given language. We apply this technique to a large number of books by several authors and examine how the vocabulary of a text changes when it is translated from one language to another. Unlike the uniform results produced using the Zipf law, using our “word energy” distribution technique we find variations in the power-law behavior. We also examine some common features that span across languages and identify some intriguing questions concerning how to determine when a text is suitable for its intended readership.

A Mean Field Model of Coupled Cascades in Flow Networks

We introduce an analytical model of cascading behavior of interdependent networks under stressing conditions and find evidence of abrupt breakdown phenomena. Our results indicate that coupling several infrastructures can diminish the impact of small cascades at the cost of increasing system wide ones. As a consequence, the enhancement of the systemic risk failures with increasing network size, represents an effect to be accounted while planning projects aiming to integrate national networks into “super-networks”.

Analysis of Gender Diversity in the Italian Community of Information Systems

We present a study on gender analysis of the Italian community of Information Systems—itAIS—based on a three-dimensional framework accounting for the context, the success, and the members’ attitudes. We represent the community as a semantic social network. We analyze the semantics of the information systems domain, the topology of the social network and the dynamics of interests by means of a suite of purposely-developed tools. The experimental work analyses the scientific papers accepted for presentation at the itAIS conference from 2007 to 2016. While the number of males is larger than that of females, we do not observe discrimination in the community. Moreover, despite observed diversity, Italian feminine scientists play a significant role in the community.

Operational Resilience Metrics for a Complex Electrical Network

The Electrical Distribution Network is a Critical Infrastructure which plays a primary role in citizen life. Resilience is a relevant property to be achieved as it allows the network to withstand all types of perturbations affecting its functions and allowing to provide its service with continuity. Resilience comes out from a combination of a number of specific properties related to both intrinsic network technologies and to operator’s management skills. This work reports on the results obtained by using a model for estimating Resilience applied to a real network (the electrical distribution network of the city of Roma) which accounts for most of the parameters influencing the effective resilience of the network. Results confirm that the model can appropriately handle a real network and provide valuable insights to electrical operators.

Availability Study of the Italian Electricity SCADA System in the Cloud

Recently, the allure of the cloud is also affecting the SCADA systems. Cloud-based commercial solutions to manage small private SCADA systems are spreading, while the utilities are still evaluating the cloud adoption. For electric utility companies, reasons for moving in the cloud can be traced to the need of storing, accessing and analyzing a huge amount of records collected from their new smart meters, and managing grid-connected small-scale decentralized energy generation from renewable sources. Moreover, the cloud allows an easy and affordable deploy of monitor dashboards, populated with accurate consumption data, accessible at anytime from anywhere, directly to the customers’ smartphones. On the other hand, cloud poses fears on security, privacy and system downtime. In this work, we focus on the latter aspect analyzing the availability of the SCADA system managing the Italian power transmission network for different possible adoptions of the cloud.

Phenomenological Simulators of Critical Infrastructures

The objective of this chapter is to introduce and discuss the main phenomenological approaches that have been used within the CI M&S area. Phenomenological models are used to analyse the organizational phenomena of the society considering its complexity (finance, mobility, health) and the interactions among its different components. Within CI MA&S, different modelling approaches have been proposed and used as, for example, physical simulators (e.g. power flow simulators for electrical networks). Physical simulators are used to predict the behaviour of the physical system (the technological network) under different conditions. As an example, electrical engineers use different kind of simulators during planning and managing of network activities for different purposes: (1) power flow simulators for the evaluation of electrical network configuration changes (that can be both deliberate changes or results from of the effects of accidents and/or attacks) and contingency analysis, (2) real time simulators for the design of protection devices and new controllers. For the telecommunication domain one mat resort to network traffic simulators as for example ns2/ns3 codes that allow the simulation of telecommunication networks (wired/wireless) at packet switching level and evaluate its performances. Single domains simulators can be federated to analyse the interactions among different domains. In contrast, phenomenological simulators use more abstract data and models for the interaction among the different components of the system. The chapter will describe the main characteristic of some of the main simulation approaches resulting from the ENEA and UBC efforts in the CIP and Complexity Science field.

A Spectral Approach to Synchronizability of Interdependent Networks

The quality of life in full developed countries depends on the cooperative functioning of different infrastructures. One of the most striking problems is to understand in simple terms to what extent this cooperation can be assured. The complexity science provides a powerful means to analyze the interaction of such critical infrastructures at pure topological level. The application of the paradigm of complexity to the global system resulting from the interdependent infrastructures leads to the concept of “Network of Networks”. The present work is devoted to understand emergent (that is collective) synchronization behaviors through the spectral analysis of the laplacian. We provide evidence that, upon increasing the number of links between the different infrastructures, the behavior of the total system experiences a drastic changes in its synchronization modes. When few links are introduced, the synchronization inside the component networks is very fast and the global synchronization takes place mainly at the boundaries; on the other side, when the number of links exceeds a threshold, the bottlenecks for the synchronization process localize mainly inside the component networks.

The robustness of assortativity (short paper)

Complex networks are ubiquitous in real word and represent a key model for both human made and natural systems. An important characteristics that distinguishes technological networks from biological networks is the assortativity, i.e. the correlation among the degrees of connected nodes. We apply spectral analysis to investigate how assortativity influences the robustness of a network with respect to failure propagations or epidemic spreading. We find a no free lunch situation: while disassortative networks are more robust since they have a higher failure threshold, in assortative networks there is more time for intervention before total breakdown.