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Authors:LUCIO BIGGIERO, ROBERT MAGNUSZEWSKI Abstract: Advances in Complex Systems, Volume 24, Issue 05, August 2021. In this paper, we investigate the ownership structure of the 3143 EU28 aerospace companies in 2019, and extend the analysis to the 2428 neighbor partners outside EU28 and/or aerospace. Different from the previous studies, we consider all equity capital flows regardless of their size, and their monetary value instead of the corresponding ownership share. We further innovate by applying new methods to measure degree of influence power and hierarchical structure. The resulting picture shows that between the pure EU28 aerospace companies: (i) ownership relationships concern only relatively few companies (10%), which trigger horizontal and vertical structures; (ii) density is extremely low; (iii) relationships are fully hierarchical with no cross-ownership; (iv) capital is seldom transferred across business groups; (v) most of the main topological parameters have a typically polarized scale-free structure. When including also the ownership neighbors, some of those traits change substantially: (i) the share of connected companies substantially grows up to 63%; (ii) size and length of the largest pyramidal structures will grow remarkably, reaching a top of 874 companies; (iii) the industry becomes a full small-world structure, thus allowing huge capital transfer across business groups. Finally, a dramatic financialization, meant as a pivotal and quantitatively heavy role of financial operators, emerges also as a clear characteristic of the extended network. Citation: Advances in Complex Systems PubDate: 2022-01-07T08:00:00Z DOI: 10.1142/S0219525921500120 Issue No:Vol. 24, No. 05 (2022)
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Authors:RICARDO SIMÃO, FRANCISCO ROSENDO, LUCAS WARDIL Abstract: Advances in Complex Systems, Ahead of Print. The role of luck on individual success is hard to be investigated empirically. Simplified mathematical models are often used to shed light on the subtle relations between success and luck. Recently, a simple model called “Talent versus Luck” showed that the most successful individual in a population can be just an average talented individual that is subjected to a very fortunate sequence of events. Here, we modify the framework of the TvL model such that in our model the individuals’ success is modelled as an ensemble of one-dimensional random walks. Our model reproduces the original TvL results and, due to the mathematical simplicity, it shows clearly that the original conclusions of the TvL model are the consequence of two factors: first, the normal distribution of talents with low standard deviation, which creates a large number of average talented individuals; second, the low number of steps considered, which allows the observation of large fluctuations. We also show that the results strongly depend on the relative frequency of good and bad luck events, which defines a critical value for the talent: in the long run, the individuals with high talent end up very successful and those with low talent end up ruined. Last, we considered two variations to illustrate applications of the ensemble of random walks model. Citation: Advances in Complex Systems PubDate: 2021-12-29T08:00:00Z DOI: 10.1142/S0219525921500107
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Authors:GIULIA BRAGHINI, FRANCESCO SALVARANI Abstract: Advances in Complex Systems, Ahead of Print. This paper studies a model for describing opinions’ evolution in a community linked by microblogging directed network systems. The network can evolve in time by means of the creation and the deletion of some connections. When a connexion is created, the individuals have access to the whole history of posts written by the corresponding author and, when a connexion is destroyed, all the posts written by the corresponding author become invisible. The agents’ opinions are described by a set of continuous opinion variables in the closed interval [math]. They represent the agreement (or disagreement) of the corresponding agent with respect to a binary question (such as a referendum or an election with two candidates). The model takes into account the effects on public opinion caused by the sign and the intensity of the initial opinions of the agents, their activity in microblogging platforms the presence of leaders and the possible manipulations of the visibility of the posts by the microblogging platform owner. The model is written as a system of integro-differential equations and simulated by using a Runge–Kutta method. We show that hidden manipulation can have an important impact on the public opinion formation and that very mild interventions of the network owner may induce major effects on the population. In our simulations, the effect of hidden manipulation is shown to be more efficient in driving the public opinion than the action of a leader, in the case of bounded confidence models and for short-time intervals. Citation: Advances in Complex Systems PubDate: 2021-11-24T08:00:00Z DOI: 10.1142/S0219525921500090
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