Echo chambers and polarisation dynamics are as of late a very prominent topic in scientific communities around the world. As these phenomena directly affect our lives, and seemingly more and more as our societies and communication channels evolve, it becomes ever so important to understand the intricacies of novel opinion dynamics in the modern era. We build upon an existing echo chambers and...
We study the q-voter model with bounded confidence on the complete graph. Agents can be in one of three states. Two types of agents behaviour are investigated: conformity and independence. We analyze whether this system is qualitatively different from a corresponding model without bounded confidence. Our main results are the following. Firstly, the system has two phase transitions: one between...
We study an agent-based model of innovation diffusion on the Watts-Strogatz random graphs. The model is based on the $q$-voter model with a noise (with nonconformity, in the terminology of social psychology), which has been previously used to describe the diffusion of green products and practices. It originates from the $q$-voter model with independence, known also as the noisy nonlinear voter...
The current world keeps evolving, and in our era the challenge of "too much data" keeps popping up, in particular in the world of portfolio optimization, therein lies the opportunity of providing more accurate results through the use of the relatively new tools developed in the random matrix theory literature to reduce the bias in the sample covariance matrix of some financial data (real or...
The main goal of our work is to show how ideas change in social networks. Our analysis is based on three concepts: (i) temporal networks [1], (ii) the Axelrod model of culture dissemination [2], (iii) the garbage can model of organizational choice [3]. The use of the concept of temporal networks allows us to show the dynamics of ideas spreading processes in networks, thanks to the analysis of...
Empirical time series of inter-event or waiting times are investigated using a modified Multifractal Detrended Fluctuation Analysis operating on fluctuations of mean detrended dynamics. The core of the extended multifractal analysis is the non-monotonic behavior of the generalized Hurst exponent $h(q)$ -- the fundamental exponent in the study of multifractals. The consequence of this behavior...
We investigate the binary $q$-voter model with generalized anticonformity on random Erdős–Rényi graphs. The generalization refers to the freedom of choosing the size of the influence group independently for the case of conformity $q_c$ and anticonformity $q_a$. This model was studied before on the complete graph, which corresponds to the mean-field approach, and on such a graph discontinuous...
Elucidating what factors are salient in emerging interactions in social networks is still an open question. Thus, we develop an agent-based model for generating interactions in signed networks. The ABMs, based on the Activity Driven Network model, use signed relations between agents to reproduce their interaction frequencies and crucial network distributions. The calibration and validation...
We applied the moving average cluster entropy to study long-range correlation, dynamics and heterogeneity of financial time series, and to propose an alternative method to portfolio estimation.
The cluster entropy relies on the Shannon entropy $S(P_i) = - \sum_i P_i \ln P_i$. The probability distribution function of each asset $i$ is obtained intersecting the asset time series $y(t)$ with...
In the age of social media there is more and more need to understand how do people create relations using those. The objective here was not only to look if relations are being created as a consequence of social interactions, but also to separate emergence of positive and negative relations. The knowledge we can gain here could benefit a wide spectrum of applications - from purely scietific to...
Macroeconomic analyses are, to a large extent, based on firm segmentation and creating homogeneous groups of entities. Thanks to this procedure one can estimate indicators (e.g., various Key Performance Indicators) with high accuracy and examine trends of the market. Unfortunately, the drawback is that segmentation algorithms based on distance measures model average values and are not suitable...
Social stratification, the division of society into groups, can result from historical and social factors and reflect economic inequality. Ethnicity, gender, and race are examples of subgroups where people belonging to one can be privileged in terms of status, power, and wealth. In fact, in many societies, dominant classes are composed of many people associated with one group, and economic...
The term "hierarchy" when applied to networks can mean one of the few structures: simple order hierarchy meaning ordering of elements, nested hierarchy that is multi-level community structure or flow hierarchy defined by directed links that show causal or control structure in the network.
We introduce two measures of node depth for flow hierarchy in directed networks, measuring the level of...
Spreading processes play an increasingly important role in modeling for diffusion networks, information propagation, marketing and opinion setting. We address the problem of learning of a spreading model such that the predictions generated from this model are accurate and could be subsequently used for the optimization, and control of diffusion dynamics. Unfortunately, full observations of the...
We introduce a generalized version of the noisy q-voter model, one of the most popular opinion dynamics models, in which voters can be in one of s≥2 states. As in the original binary q-voter model, which corresponds to s=2, at each update randomly selected voter can conform to its q randomly chosen neighbors (copy their state) only if all q neighbors are in the same state. Additionally, a...
One of the challenges faced by today's societies is to deal with the growing polarization. Here, we propose an agent-based model incorporating theories of structural balance and homophily. Most of the literature identify a structurally balanced state as a polarized one. However, we show that these two states are not always equivalent. We study a multilayer system with one layer related to the...
I present the issue of quantifying the impact of modern maritime piracy practises on world trade. For this purpose the case of Somali piracy is investigated. Data is carefully analysed with the statistical methodology of modern empirical economics to identify the causal effect of pirate attacks on trade volumes and transportation costs. This is a good example for the detection of small causal...
A new type of in-depth microscopic analysis is presented for the Yard-Sale model, one of the most well known multi-agent market exchange models. This approach led to the classification and study of the individual strategies carried out by the agents undergoing transactions, as given by their risk propensity. These findings allowed to determine a region of parameters for which the strategies...
The Covid-19 pandemic has affected not only economies of particular countries but the entire world economic system. It is not surprising that also currency exchange rates are not left untouched by the current crisis. The main objective of our study here is to assess the similarity between the time series of currency exchange rates and the Covid-19 time series (e.g., we investigate the...
The Axelrod model is a well known model of culture development and dissemination describing a possible mechanism for emergence of cultural domains. It is based on two sociological phenomena: homophily and the theory of social influence. Technically, it assumes that every culture is represented by a vector of F cultural traits (features), each taking any of q allowed opinions (values). The...
