- Florence, Toscana, Italy
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In the past three decades, fractional and fractal calculus (that is, calculus of derivatives and integral of any arbitrary real or complex order) appeared to be an important tool for its applications in many fields of science and... more
In the past three decades, fractional and fractal calculus (that is, calculus of derivatives and integral of any arbitrary real or complex order) appeared to be an important tool for its applications in many fields of science and engineering. This theory allows to face, analytically and/or numerically, fractional differential equations and fractional partial differential equations. In particular, one of the several applications deals with anomalous diffusion processes. The latter phenomena can be clearly described from the statistical viewpoint. Indeed, in various complex systems, the diffusion processes usually no longer follow Gaussian statistics, and thus Fick’s second law fails to describe the related transport behavior. In particular, one observes deviations from the linear time dependence of the mean squared displacement 〈 x (t) 〉 ∝ t, (1)
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Dido solved the first isoperimetric problem in history by cutting an oxhide into strips, tying them together and surrounding with the resulting rope the portion of land where Carthage was to be built. However, Dido’s feat can be improved... more
Dido solved the first isoperimetric problem in history by cutting an oxhide into strips, tying them together and surrounding with the resulting rope the portion of land where Carthage was to be built. However, Dido’s feat can be improved on, as can be shown by cutting an opening in a postcard in such a way that a person is able to pass through it.
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In teaching physics one works hard to make pupils understand that all masses fall with the same acceleration. However, if we drop compound bodies, some parts of them can actually “go faster” than free fall. This experiment can be easily... more
In teaching physics one works hard to make pupils understand that all masses fall with the same acceleration. However, if we drop compound bodies, some parts of them can actually “go faster” than free fall. This experiment can be easily accomplished with a chain and a dumbbell. Here we try to provide a simple explanation for this apparently impossible effect.
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Ihusan Adam, 2 Franco Bagnoli, 3 Duccio Fanelli, 3 L. Mahadevan, and Paolo Paoletti Department of Information Engineering, University of Florence, Florence, Italy Department of Physics and Astronomy, and CSDC, University of Florence,... more
Ihusan Adam, 2 Franco Bagnoli, 3 Duccio Fanelli, 3 L. Mahadevan, and Paolo Paoletti Department of Information Engineering, University of Florence, Florence, Italy Department of Physics and Astronomy, and CSDC, University of Florence, Sesto Fiorentino, Italy INFN, Florence Section, Sesto Fiorentino, Italy School of Engineering and Applied Sciences, Department of Physics, and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA School of Engineering, University of Liverpool, L69 3GH Liverpool, UK
Research Interests: Physics and Tensegrity
This review article focuses on studying problems of observability and controllability of cellular automata (CAs) considered in the context of control theory, an important feature of which is the adoption of a state-space model. Our work... more
This review article focuses on studying problems of observability and controllability of cellular automata (CAs) considered in the context of control theory, an important feature of which is the adoption of a state-space model. Our work first consists in generalizing the obtained results to systems described by CAs considered as the discrete counterpart of partial differential equations, and in exploring possible approaches to prove controllability and observability. After having introduced the notion of control and observation in cellular automata models, in a similar way to the case of discrete-time distributed parameter systems, we investigate these key concepts of control theory in the case of complex systems. For the controllability issue, the Boolean class is particularly studied and applied to the regional case, while the observability is approached in the general case and related to the reconstructibility problem for linear or nonlinear CAs.
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ABSTRACT Previous works have analyzed the cluster organization of the cat cortical network using both traditional multidimensional scaling methods and evolutionary optimization algorithms. Interestingly, the evolutionary optimization... more
ABSTRACT Previous works have analyzed the cluster organization of the cat cortical network using both traditional multidimensional scaling methods and evolutionary optimization algorithms. Interestingly, the evolutionary optimization principle of previous works is based on the modularity measure used to find communities in network with global algorithms. In this paper, we deepen this point taking into account different community-detection algorithms. We compare the performances of Net Explorer, a local information dynamics algorithm for detecting communities in networks, with six well-known community detection algorithms: Info map, Hierarchical Info map, Lou vain, Modularity Optimization, Label Propagation and Oslom. The results indicate that Net Explorer is able to detect the four functional clusters where misattributions of some areas are explained by their multimodal function. Results are discussed in terms of misattributions of brain areas to the different clusters emphasizing connections which are explainable (or not) by a cognitive point of view.
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Intimate partner violence (IPV) has been a well-studied problem in the past psychological literature, especially through its classical methodology such as qualitative, quantitative and mixed methods. This article introduces two basic... more
Intimate partner violence (IPV) has been a well-studied problem in the past psychological literature, especially through its classical methodology such as qualitative, quantitative and mixed methods. This article introduces two basic stochastic models as an alternative approach to simulate the short and long-term dynamics of a couple at risk of IPV. In both models, the members of the couple may assume a finite number of states, updating them in a probabilistic way at discrete time steps. After defining the transition probabilities, we first analyze the evolution of the couple in isolation and then we consider the case in which the individuals modify their behavior depending on the perceived violence from other couples in their environment or based on the perceived informal social support. While high perceived violence in other couples may converge toward the own presence of IPV by means a gender-specific transmission, the gender differences fade-out in the case of received informal social support. Despite the simplicity of the two stochastic models, they generate results which compare well with past experimental studies about IPV and they give important practical implications for prevention intervention in this field.
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The emergence and the global adaptation of mobile devices has influenced human interactions at the individual, community, and social levels leading to the so called Cyber-Physical World (CPW) convergence scenario [1]. One of the most... more
The emergence and the global adaptation of mobile devices has influenced human interactions at the individual, community, and social levels leading to the so called Cyber-Physical World (CPW) convergence scenario [1]. One of the most important features of CPW is the possibility of exploiting information about the structure of social communities of users, that manifest through joint movement patterns and frequency of physical co-location: mobile devices of users that belong to the same social community are likely to "see" each other (and thus be able to communicate through ad hoc networking techniques) more frequently and regularly than devices outside of the community. In mobile opportunistic networks, this fact can be exploited, for example, to optimize networking operations such as forwarding and dissemination of messages. In this paper we present a novel local cognitive-inspired algorithm for revealing the structure of these dynamic social networks by exploiting information about physical encounters, logged by the users' mobile devices as they encounter each other. We show that with our approach, that mimics - locally at each node - the epidemic spread of information in the network induced by the observed frequency and regularity of contacts, we are able to detect not only the existing communities but also to identify dynamic interactions among the individuals. Thus, the main features of our scheme are: (i) the capacity of detecting social communities induced by physical co-location of users through distributed, online algorithms; (ii) the capacity to detect users belonging to more communities (thus acting as bridges across them), and (iii) the capacity to detect the dynamics of communities evolution over time.
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ABSTRACT With the availability of detailed information about the connectivity among brain areas, network analysis tools have been applied to datasets comprising cat and macaque cortical networks. Using evolutionary optimization algorithms... more
ABSTRACT With the availability of detailed information about the connectivity among brain areas, network analysis tools have been applied to datasets comprising cat and macaque cortical networks. Using evolutionary optimization algorithms (based on global analysis of the network), similarities between anatomical connections and functional properties of the areas of the brain have been found in previous works. To find functional properties of the brain, we have applied NetExplorer, a novel community detection algorithm based on local information dynamics, to two different datasets of cortical connectivity. We have compared the performances of NetExplorer with the results obtained by other six algorithms (Infomap, Hierarchical Infomap, Louvain, Modularity Optimization, Label Propagation and Oslom) with the same two datasets of cortical connectivity. In both datasets, NetExplorer places among the best algorithms in predicting the actual functional cortical clusters. We discuss the algorithm results considering the misattributions of brain areas to the different clusters and emphasizing the connections that are explainable by their multimodal functions.
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ABSTRACT We present a research framework consisting of a standard chat environment and a set of analytical tools, able to detect some relevant characteristics of the group dynamics of interacting people. The analysis is independent of the... more
ABSTRACT We present a research framework consisting of a standard chat environment and a set of analytical tools, able to detect some relevant characteristics of the group dynamics of interacting people. The analysis is independent of the semantic content of the exchanged messages, and the standardized interface avoids hard-to-detect non-verbal communications, still providing the expression of emotional contents. This study proposes a quantitative approach to the investigation of the cognitive small group dynamics, considering the personal representation of the others, and communication dynamics. We developed a framework for the analysis that merges the complex network theory with concepts from social psychology and sociophysics. The focus of the framework is a quantitative investigation of how people explore and build their cognitive representation of the social space. Moreover two different experimental tasks have been proposed in order to investigate the role of some ecological constraints on the cognitive heuristics used by the subjects. The results show how people behave differently with respect to the task they are facing. In particular the absolute and the relative frequencies of the messages and their qualitative aspects significantly differ between the two conditions, as so as the cognitive strategies used by subjects to assess the affinity with the others.
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Research Interests: Cognitive Psychology, Computer Science, Technology, Interpersonal Communication, Heuristics, and 12 moreData Analysis, Social Behaviour, Network Dynamics, Complex network, Analogy, Social Dynamics, Social dynamic, Emergent Properties, Estimator, Dynamic System, Statistical Estimation, and Social Network
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Intimate partner violence (IPV) is a significant public health problem and social issue that involves couples from all socioeconomic and cultural contexts. IPV may affect women and men, but these latter are the most common perpetrators of... more
Intimate partner violence (IPV) is a significant public health problem and social issue that involves couples from all socioeconomic and cultural contexts. IPV may affect women and men, but these latter are the most common perpetrators of IPV. We developed stochastic Agent-Based models of IPV focused on the couple dynamics, determined by the parallel, individual behaviour of partners. Based on the psychological theory of the Cycle of Violence, we have developed a model based on four discrete states: passivity, normal situation, upset and physical assault. The individual transition probability depends on the previous state of the subject and that of the partner, and on a control parameter, the aggressiveness. We then let this parameter evolve depending on the perceived violence from past experiences (polarisation) or from the support received from the environment (social influence). From the analysis of the phase diagrams we observe the emergence of characteristic patterns, in agreem...
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Reputation is one of the most effective solutions to the so-called «puzzle of cooperation», but it is usually studied in contexts in which information is not ambiguous and there are no incentives towards strategically using it. In this... more
Reputation is one of the most effective solutions to the so-called «puzzle of cooperation», but it is usually studied in contexts in which information is not ambiguous and there are no incentives towards strategically using it. In this study, we test wheter the possibility of being evaluated (with a like or a dislike) when giving suggestions about a deal in a competitive game has an effect on truthfulness of suggestions. We designed a computer-mediated experiment and we tested adolescents in a high-school in Italy, with the aim of understanding the development of reputational dynamics and how adolescents deal with competing incentives. Our results show that when reputations introduced, adolescents become more cooperative, both in terms of donations to partners and of suggestions offered. We also observe that reputations, both positive and negative, behave as attractors, thus those of ill-repute receive negative reviews even when they cooperate, and individuals with positive reputati...
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espanolEste experimento forma parte de un conjunto de lecciones desarrolladas por F. Bagnoli para introducir la fisica a un publico muy heterogeneo y no experto. La idea es presentar los temas de fisica como una especie de espectaculo,... more
espanolEste experimento forma parte de un conjunto de lecciones desarrolladas por F. Bagnoli para introducir la fisica a un publico muy heterogeneo y no experto. La idea es presentar los temas de fisica como una especie de espectaculo, conectandolos con los asuntos de la vida real, haciendo hincapie en los principios comunes, mas alla de los ejemplos o casos particulares tratados. Este material tambien se puede usar en un curso estandar de fisica, como una manera de mostrar a los estudiantes que los temas que se trabajan en el curso forman parte de la vida diaria. EnglishThis experiment is part of a series of lessons for introducing physics to laymen. The idea is that of presenting topics in physics as a kind of show, connecting them to topics in real life, trying to focus on the common principles that are beyond the variety of possible examples. This material can be also used in standard physics course as a way of convincing students that what they study in their course is actually...
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espanolEste experimento se presenta ante el publico asistente a un evento cientifico acompanado por la lectura de un comic. Asi, de modo simpatico se propicia la reflexion sobre un hecho fisico bien conocido a nivel practico y bastante... more
espanolEste experimento se presenta ante el publico asistente a un evento cientifico acompanado por la lectura de un comic. Asi, de modo simpatico se propicia la reflexion sobre un hecho fisico bien conocido a nivel practico y bastante utilizado, pero cuyos fundamentos fisicos no siempre se comprenden: al introducir sal entre hielo se reduce la temperatura de la mezcla y se derrite el hielo. EnglishA popular comic is used to introduce this experiment. This sympathetic way reflection on a physical fact well known to practical level and fairly used, but whose physical fundamentals are not always understood: introducing salt in ice is reduced the temperature of the mixture, and the ice melts.