Antonio Scala

Italian National Research Council | CNR · Institute for Complex Systems ISC

BACKGROUND: The typical reaction strategy to an epidemic involves the implementation of various pharmaceutical (e.g., vaccination) and non-pharmaceutical interventions (e.g., social distancing) to reach the so-called "herd immunity threshold," ensuring that new surges of the epidemic dampen out. AIM: We introduce a novel concept: the "Herd Immunity...

The urgency to develop vaccines during the COVID-19 pandemic has resulted in the acceleration of clinical trials. Specifically, a broad spectrum of efficacy levels has been reported for various vaccines based on phase III cohort studies. Our study demonstrates that conducting large cohort phase III clinical trials during the peak of an epidemic lea...

Social media platforms heavily changed how users consume and digest information and, thus, how the popularity of topics evolves. In this paper, we explore the interplay between the virality of controversial topics and how they may trigger heated discussions and eventually increase users' polarization. We perform a quantitative analysis on Facebook...

The vaccine rush caused by the current pandemic has led to performing fast clinical trials; in particular, we have observed a wide range of reported efficacy for the different vaccines from phase III cohort studies. We show that we show that when performing large cohorts phase III clinical trials near the epidemic peak, the measured effectiveness r...

Networks have always played a special role for human beings in shaping social relations, forming public opinion, and driving economic equilibria. Nowadays, online networked platforms dominate digital markets and capitalization leader-boards, while social networks drive public discussion. Despite the importance of networks in many economic and socia...

In this paper, we develop a general Open Multi-Agent Systems (OMAS) framework over undirected graphs where the agents' interaction is, in general, nonlinear, time-varying, and heterogeneous, in that the agents interact with different pairwise interaction rules for each link, possibly nonlinear, which may change over time. In particular, assuming th...

Social media platforms heavily changed how users consume and digest information and, thus, how the popularity of topics evolves. In this paper, we explore the interplay between the virality of controversial topics and how they may trigger heated discussions and eventually increase users' polarization. We perform a quantitative analysis on Facebook...

Networks have always played a special role for human beings in shaping social relations, forming public opinion, and driving economic equilibria. Nowadays, online networked platforms dominate digital markets and capitalization leader-boards, while social networks drive public discussion. Despite the importance of networks in many economic and socia...

COVID-19 has got us to face a new situation where, for the lack of ready-to-use vaccines, it is necessary to support vaccination with complex non-pharmaceutical strategies. In this paper, we provide a novel Mixed Integer Nonlinear Programming formulation for fine-grained optimal intervention planning (i.e., at the level of the single day) against n...

The COVID-19 information epidemic, or “infodemic,” demonstrates how unlimited access to information may confuse and influence behaviors during a health emergency. However, the study of infodemics is relatively new, and little is known about their relationship with epidemics management. Here, we discuss unresolved issues and propose research directi...

A correlation analysis based on Markowitz Portfolio Theory and data from meteorological station are used to develop a decision-making tool for the optimal spatial installation of renewable energy sources from Wind turbines and PV panels. A case study involving power generation plants and weather stations in the region of Tuscany in Italy is develop...

The COVID-19 pandemic is one of the defining events of our time. National Governments responded to the global crisis by implementing mobility restrictions to slow down the spread of the virus. To assess the impact of those policies on human mobility, we perform a massive comparative analysis on geolocalized data from 13 M Facebook users in France,...

While vaccination is the optimal response to an epidemic, recent events have obliged us to explore new strategies for containing worldwide epidemics, like lockdown strategies, where the contacts among the population are strongly reduced in order to slow down the propagation of the infection. By analyzing a classical epidemic model, we explore the i...

Near real-time monitoring and control of critical infrastructure is essential for the operation and management of cities in a world that is, today, more complex and interconnected than ever. Such an infrastructure can be represented as complex networks an some of their related indices and statistics, many of them based on the shortest paths, play a...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Most real-world networks, from the World-Wide-Web to biological systems, are known to have common structural properties. A remarkable point is fractality, which suggests the self-similarity across scales of the network structure of these complex systems. Managing the computational complexity for detecting the self-similarity of big-sized systems re...

This chapter shows two examples of application complex networks and stochastic systems to energy systems. Two case studies are taken into consideration: the first one illustrates how regional-scale electric mobility can be planned with the help of complex network science, while the second shows how stochastic systems and Markowitz portfolios can be...

We address the diffusion of information about the COVID-19 with a massive data analysis on Twitter, Instagram, YouTube, Reddit and Gab. We analyze engagement and interest in the COVID-19 topic and provide a differential assessment on the evolution of the discourse on a global scale for each platform and their users. We fit information spreading wit...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

We develop a minimalist compartmental model to study the impact of mobility restrictions in Italy during the Covid-19 outbreak. We show that, while an early lockdown shifts the contagion in time, beyond a critical value of lockdown strength the epidemic tends to restart after lifting the restrictions. We characterize the relative importance of diff...

Recent studies have shown that online users tend to select information that adheres to their system of beliefs, ignore information that does not, and join groups that share a common narrative. This information environment can elicit tribalism instead of informed debate, especially when issues are controversial. Algorithmic solutions, fact-checking...

Significance This paper presents a large-scale analysis of the impact of lockdown measures introduced in response to the spread of novel coronavirus disease 2019 (COVID-19) on socioeconomic conditions of Italian citizens. We leverage a massive near–real-time dataset of human mobility and we model mobility restrictions as an exogenous shock to the e...

The policies implemented to hinder the COVID-19 outbreak represent one of the largest critical events in history. The understanding of this process is fundamental for crafting and tailoring post-disaster relief. In this work we perform a massive data analysis, through geolocalized data from 13M Facebook users, on how such a stress affected mobility...

In response to the COVID-19 pandemic, National governments have applied lockdown restrictions to reduce the infection rate. We perform a massive analysis on near real-time Italian data provided by Facebook to investigate how lockdown strategies affect economic conditions of individuals and local governments. We model the change in mobility as an ex...

We develop a minimalist compartmental model to analyze policies on mobility restriction in Italy during the Covid-19 outbreak. Our findings show that a early lockdowns barely shift the epidemic in time: moreover, beyond a critical value of the lockdown strength, an epidemic that seems to be quelled fully recovers after lifting the restrictions. We...

The detection of contaminant intrusion into a water-distribution network (WDN) is a difficult issue due to uncertainty related to the type of injected contaminant, source location, and intrusion time. The placement of water quality sensors has received increasing interest in the last years, and it still represents an open problem and a great challe...

The social brain hypothesis approximates the total number of social relationships we are able to maintain at 150. Similar cognitive constraints emerge in several aspects of our daily life, from our mobility to the way we communicate, and might even affect the way we consume information online. Indeed, despite the unprecedented amount of information...

Despite their entertainment oriented purpose, social media changed the way users access information, debate, and form their opinions. Recent studies, indeed, showed that users online tend to promote their favored narratives and thus to form polarized groups around a common system of beliefs. Confirmation bias helps to account for users’ decisions a...

Recent studies, targeting Facebook, showed the tendency of users to interact with information adhering to their preferred narrative and to ignore dissenting information. Primarily driven by confirmation bias, users tend to join homogeneous and polarized clusters (i.e., echo chambers) where they cooperate to frame and reinforce a like-minded system...

Recent studies, targeting Facebook, showed the tendency of users to interact with information adhering to their preferred narrative and to ignore dissenting information. Primarily driven by confirmation bias, users tend to join homogeneous and polarized clusters (i.e., echo chambers) where they cooperate to frame and reinforce a like-minded system...

Despite their playful purpose social media changed the way users access information, debate, and form their opinions. Recent studies, indeed, showed that users online tend to promote their favored narratives and thus to form polarized groups around a common system of beliefs. Confirmation bias helps to account for users’ decisions about whether to...

The aim of the sparse analytic hierarchy process (SAHP) problem is to rank a set of alternatives based on their utility/importance; this task is accomplished by asking human decision-makers to compare selected pairs of alternatives and to specify relative preference information, in the form of ratios of utilities. However, such an information is of...

This paper proposes a dimension reduction process for computing the Dijkstra's shortest path algorithm in a complex network. This is done through a novel multiscale (MS) network decomposition into base-elements: links and landmark-nodes. All of them result to be essential for keeping all the network connectivity information and for speeding up the...

This paper proposes a dimension reduction process for computing the Dijkstra's shortest path algorithm in a complex network. This is done through a novel multiscale (MS) network decomposition into base-elements: links and landmark-nodes. All of them result to be essential for keeping all the network connectivity information and for speeding up the...

According to the World Economic Forum, the diffusion of unsubstantiated rumors on online social media is one of the main threats for our society. The disintermediated paradigm of content production and consumption on online social media might foster the formation of homogeneous communities (echo-chambers) around specific worldviews. Such a scenario...

The wide availability of user-provided content in online social media facilitates the aggregation of people around common interests, worldviews, and narratives. However, the World Wide Web (WWW) also allows for the rapid dissemination of unsubstantiated rumors and conspiracy theories that often elicit rapid, large, but naive social responses such a...

Social media enabled a direct path from producer to consumer of contents changing the way users get informed, debate, and shape their worldviews. Such a disintermediation might weaken consensus on social relevant issues in favor of rumors, mistrust, or conspiracy thinking-e.g., chem-trails inducing global warming, the link between vaccines and auti...

In this work we present a thorough quantitative analysis of information consumption patterns of qualitatively different information on Facebook. Pages are categorized, according to their topics and the communities of interests they pertain to, in a) alternative information sources (diffusing topics that are neglected by science and main stream medi...

The large availability of user provided contents on online social media facilitates people ag-gregation around shared beliefs, interests, worldviews and narratives. In spite of the enthusiastic rhetoric about the so called collective intelligence unsubstantiated rumors and conspiracy theories-e.g., chemtrails, reptilians or the Illuminati-are perva...

Users online tend to select information that support and adhere their beliefs, and to form polarized groups sharing the same view-e.g. echo chambers. Algorithms for content promotion may favour this phenomenon, by accounting for users preferences and thus limiting the exposure to unsolicited contents. To shade light on this question, we perform a c...

Recent findings showed that users on Facebook tend to select information that adhere to their system of beliefs and to form polarized groups-i.e., echo chambers. Such a tendency dominates information cascades and might affect public debates on social relevant issues. In this work we explore the structural evolution of communities of interest by acc...

Do echo chambers actually exist on social media? By focusing on how both Italian and US Facebook users relate to two distinct narratives (involving conspiracy theories and science), we offer quantitative evidence that they do. The explanation involves users' tendency to promote their favored narratives and hence to form polarized groups. Confirmati...

Despite the scientific evidences, anthropogenic climate change is still a strongly controversial subject. Since the subject is relevant for the well-being of future generations, it should be discussed on a neutral ground; however, denial campaigns in many nations enhance the polarization on the subject and often opposite views are linked to differe...

The social brain hypothesis fixes to 150 the number of social relationships we are able to maintain. Similar cognitive constraints emerge in several aspects of our daily life, from our mobility up to the way we communicate, and might even affect the way we consume information online. Indeed, despite the unprecedented amount of information we can ac...

The social brain hypothesis fixes to 150 the number of social relationships we are able to maintain. Similar cognitive constraints emerge in several aspects of our daily life, from our mobility up to the way we communicate, and might even affect the way we consume information online. Indeed, despite the unprecedented amount of information we can ac...

In 2017, the surface water resources of central Italy suffered from a combination of dry weather and increased human extraction. Specifically, the water level of the main surface drinking water reservoir supplying the City of Rome (Lake Bracciano) is currently low and the lacustrine ecosystem is in an unstable state. The aim of this study is to des...

Users’ polarization and confirmation bias play a key role in misinformation spreading on online social media. Our aim is to use this information to determine in advance potential targets for hoaxes and fake news. In this article, we introduce a framework for promptly identifying polarizing content on social media and, thus, “predicting” future fake...

We take inspiration from the Modern Portfolio Theory introduced by Markowitz to propose a simplified strategy for the portfolio management of renewable energy sources based on Gaussian fluctuations with tunable correlations. By analyzing the impact of production fluctuations, we show how – depending on the sources' temporal correlation patterns – a...

The advent of social networks revolutionized the way people access to information sources. Understanding the complex relationship between these sources and users is crucial. We introduce an algorithm, that we call PopRank, to assess both the Impact of Facebook pages as well as users’ Engagement on the basis of their mutual interactions. The ideas b...

Most of classical decision making processes aim at selecting the “best” alternative or at ranking alternatives based on the opinions of decision makers. Often, such a process occurs among people (experts or decision makers) who are expected to achieve some shared consensus in ranking the alternatives. However, this is not likely to happen (especial...

The claim of Cambridge Analytica, a political consulting firm, that it was possible to influence voting behavior by using data mined from the social platform Facebook created a sudden fear in its users of being manipulated; consequently, even the market price of the social platform was shocked.We propose a case study analyzing the effect of this da...

Users online tend to acquire information adhering to their system of beliefs and to ignore dissenting information. Such dynamics might affect page popularity. In this paper we introduce an algorithm, that we call PopRank, to assess both the Impact of Facebook pages as well as users' Engagement on the basis of their mutual interactions. The ideas be...

Installing an efficient monitoring and control sensor system provides the possibility to carry out main tasks on Water Distribution Networks (WDNs) management and protection. Given the WDNs complexity, efficient numerical techniques are needed to support optimal monitoring system design. Generally, it is appropriate to locate sensors at highly conn...

The advent of WWW changed the way we can produce and access information. Recent studies showed that users tend to select information that is consistent with their system of beliefs, forming polarized groups of like-minded people around shared narratives where dissenting information is ignored. In this environment, users cooperate to frame and reinf...

Water Distribution Networks (WDNs) can be regarded as complex networks and modeled as graphs. In this paper, Complex Network Theory is applied to characterize the behavior of WDNs from a topological point of view, reviewing some basic metrics, exploring their fundamental properties and the relationship between them. The crucial aim is to understand...

The demand for provisioning, using, and maintaining distributed computational resources is growing hand in hand with the quest for ubiquitous services. Centralized infrastructures such as cloud computing systems provide suitable solutions for many applications, but their scalability could be limited in some scenarios, such as in the case of latency...

Users polarization and confirmation bias play a key role in misinformation spreading on online social media. Our aim is to use this information to determine in advance potential targets for hoaxes and fake news. In this paper, we introduce a general framework for promptly identifying polarizing content on social media and, thus, "predicting" future...

Users polarization and confirmation bias play a key role in misinformation spreading on online social media. Our aim is to use this information to determine in advance potential targets for hoaxes and fake news. In this paper, we introduce a general framework for promptly identifying polarizing content on social media and, thus, "predicting" future...

We study how renewable energy impacts regional infrastructures considering the full deployment of electric mobility at that scale. We use the Sardinia Island in Italy as a paradigmatic case study of a semi-closed system both by energy and mobility point of view. Human mobility patterns are estimated by means of census data listing the mobility dyna...

Background: Vaccine hesitancy has been recognized as a major global health threat. Having access to any type of information in social media has been suggested as a potential influence on the growth of anti-vaccination groups. Recent studies w.r.t. other topics than vaccination show that access to a wide amount of content through the Internet witho...

This book constitutes revised selected papers from the 12th International Conference on Critical Information Infrastructures Security, CRITIS 201, held in Lucca, Italy, in October 2017. The 21 full papers and 4 short papers presented were carefully reviewed and selected from 63 submissions. They present innovative research and explore new challeng...

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...

The Analytic Hierarchy Process (AHP) is a de-facto standard technique in centralized decision making. Consider a situation where there is a need to rank a set of elements or alternatives, based on their value or utility, of which we just know pairwise relative information, i.e., the ratio of their values. AHP proved an effective tool to retrieve th...

Social media aggregate people around common interests eliciting collective framing of narratives and worldviews. However, in such a disintermediated environment misinformation is pervasive and attempts to debunk are often undertaken to contrast this trend. In this work, we examine the effectiveness of debunking on Facebook through a quantitative an...

While the effects of climate change unfold and become more visible, infrastructures – especially those related to the distribution of water and energy – are the most exposed to the deep changes expected in the next years. Water is fundamental for people, and for infrastructures like energy, waste, and food production. Water sustainability is theref...

In this chapter we study the access time on random walks, i.e., the expected time for a random walk starting at a node \(v_i\) to reach a node \(v_j\), an index that can be easily calculated resorting to the powerful tools of positive systems. In particular, we argue that such an index can be the base for developing novel topological descriptors, n...

Significance Social media heavily changed the way we get informed and shape our opinions. Users’ polarization seems to dominate news consumption on Facebook. Through a massive analysis on 920 news outlets and 376 million users, we explore the anatomy of news consumption on Facebook on a global scale. We show that users tend to confine their attenti...

Nowadays users get informed and shape their opinion through social media. However, the disintermedi-ated access to contents does not guarantee quality of information. Selective exposure and confirmation bias, indeed, have been shown to play a pivotal role in content consumption and information spreading. Users tend to select information adhering (a...

Facebook is flooded by diverse and heterogeneous content, from kittens up to music and news, passing through satirical and funny stories. Each piece of that corpus reflects the heterogeneity of the underlying social background. In the Italian Facebook we have found an interesting case: a page having more than 40K followers that every day posts the...

Negli ultimi tre decenni stiamo assistendo ad un aumento della pressione antropica sull’ambiente, causata da diversi fattori come la crescita della popolazione sia rurale che urbana o il rapido sviluppo dei paesi emergenti. Infatti, con l’incremento della popolazione urbana vi è la necessità urgente di far fronte a una sfida multiforme che coinvolg...

Islanding is known as a management procedure of the power system that is implemented at the distribution level to preserve sensible loads from outages and to guarantee the continuity in electricity supply, when a high amount of distributed generation occurs. In this paper we study islanding on the level of the transmission grid and shall show that...

We use a simple model of distress propagation (the sandpile model) to show how financial systems are naturally subject to the risk of systemic failures. Taking into account possible network structures among financial institutions, we investigate if simple policies can limit financial distress propagation to avoid system-wide crises, i.e. to dampen...

The World Economic Forum listed massive digital misinformation as one of the main threats for our society. The spreading of unsubstantiated rumors may have serious consequences on public opinion such as in the case of rumors about Ebola causing disruption to health-care workers. In this work we target Facebook to characterize information consumptio...

On social media algorithms for content promotion, accounting for users preferences, might limit the exposure to unsolicited contents. In this work, we study how the same contents (videos) are consumed on different platforms -- i.e. Facebook and YouTube -- over a sample of $12M$ of users. Our findings show that the same content lead to the formation...

Online users tend to select claims that adhere to their system of beliefs and to ignore dissenting information. Confirmation bias, indeed, plays a pivotal role in viral phenomena. Furthermore, the wide availability of content on the web fosters the aggregation of likeminded people where debates tend to enforce group polarization. Such a configurati...

Recent findings showed that users on Facebook tend to select information that adhere to their system of beliefs and to form polarized groups -- i.e., echo chambers. Such a tendency dominates information cascades and might affect public debates on social relevant issues. In this work we explore the structural evolution of communities of interest by...

A crucial feature in implementing the next generation of smart grids is how to introduce self-healing capabilities allowing to ensure a high quality of service to the users. We show how distributed communication protocols can enrich complex networks with self-healing capabilities; an obvious field of applications are infrastructural networks. In pa...

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 system...

Public utilities, such as electricity, telecommunication, natural gas, water or sewage, constitute services whose proper functioning is of paramount importance for the whole society. Among these critical infrastructures, power grid and telecommunication network are, probably, the most critical ones. Their interdependency could exacerbate the conseq...

A crucial feature in implementing the next generation of smart grids is how to introduce self-healing capabilities allowing to ensure a high quality of service to the users. We show how distributed communication protocols can enrich complex networks with self-healing capabilities; an obvious field of applications are infrastructural networks. In pa...