Multimedialne seminarium z ekono- i socjofizyki
2009/2010 | 2010/2011 | 2011/2012 | 2012/2013 | 2013/2014 | 2014/2015 | 2015/2016 | 2016/2017 | 2017/2018 | 2018/2019 | 2019/2020 | 2021/2022 | 2022/2023 | 2023/2024
2023-04-25 (Wtorek)
Zapraszamy na spotkanie o godzinie 18:00 
Mateusz Wilinski (Los Alamos National Laboratory)Statistical Inference, Learning and Optimization for Dynamics on Networks
Long distance connections in the modern interconnected world play an important role in many areas of life, such as information spreading, epidemics, financial contagion or opinion dynamics. This drives the need for proper understanding of diffusion and spreading processes on networks. Another unprecedented feature of the current era is the data availability, which, together with rapid development of machine learning tools, allow us to learn and predict models from observed processes. In reality, however, these large amounts of data are often incomplete, noisy or biased. We address this problem in the case of spreading processes on networks and propose a general framework, which allows us to learn, predict and optimize spreading models from data, when the latter is incomplete or subject to uncertainty. We also describe the general philosophy behind our idea and how it could be used with different inference methods. Additionally, we show how the procedure can be improved when additional information about the process is known.join us via zoomhttps://us02web.zoom.us/j/82025295160?pwd=Rno0Skx6Q3haRzVzZy90dkRrbmxQQT09Meeting ID: 820 2529 5160Passcode: 794269
2023-03-21 (Wtorek)
Zapraszamy na spotkanie o godzinie 18:00
Adam Sulik (Technical University of Warsaw)Evolution of signed relations due to principles of structural balance and status theories
One of the issues of social science is the analysis of why and how human relationships are formed. The causes of these phenomena are explainedby structural balance theory and status theory, among others. Although the structural balance model by Antal et al. is a breakthrough in modeling the formation of social relationship structures, but by the diverse nature of positive and negative relationships in real-world social networks, it is unable to capture a complete picture of the relationships between users of different online communities. In addition to stability as understood by Heider’s hypothesis, which is contained in structural balance theory, dynamics based on social status should also be taken into account.We present two new models: an extended model of structural balance on directed networks and a model combining dynamics of structural balance and status theories. Presented numerical simulation results are consistent with analytical expectations. The theoretical observations have been verified on real networks, where the effect of status on the relationship between users of the studied websites has been noticed.join us via zoomhttps://us02web.zoom.us/j/82025295160?pwd=Rno0Skx6Q3haRzVzZy90dkRrbmxQQT09Meeting ID: 820 2529 5160Passcode: 794269
2022-11-29 (Wtorek)
Zapraszamy na spotkanie o godzinie 18:30
Tomasz Raducha (University Carlos III of Madrid)Multilayer structure enhances the optimal outcome of coordination games
We consider the two-player general coordination game [1] described by a payoff matrixwith two parameters. It contains a socialdilemma -- the most rewarding outcome is obtained if bothplayers choose the same strategy, but there is a hidden trade offbetween security and profit. The highest possible profit is madewhen both play the payoff-dominantor Pareto-optimal strategy. On the other hand, the risk-dominant strategyis the best choice in the lack of knowledge, i.e. it is the strategy thatresults in the highest average payoff assuming that the opponentwill play either way with the same probability.We study a population of players participating in two games ontwo inter-connected layers.A given node can be present on both layersor only on one of them. If it is present on both, it plays the samestrategy everywhere. The fraction of nodes shared between the layersis controlled by the node overlap parameter. Players on each layer are engaged in different games, i.e. parametersdefining the payoff matrix have different valueson each layer. In order to give the same relevance to both layers,their preferences towards one of the equilibria are set to beequally strong, thereforegames are truly symmetrical.In our multilayer model, which strategy is risk-dominantdepends on the layer, but coordination on the Pareto-optimal strategy prevailsin most of the parameters space or is at least favoured on average.This symmetry breaking is a clear indication that the multilayer structureenhances the Pareto-optimal outcome and it does so ina complex manner.[1] Tomasz Raducha, Maxi San Miguel. "Coordination and equilibrium selection in games: the role of local effects." Scientific reports 12.1 (2022): 1-16. join us via zoomhttps://us02web.zoom.us/j/82025295160?pwd=Rno0Skx6Q3haRzVzZy90dkRrbmxQQT09Meeting ID: 820 2529 5160Passcode: 794269
2022-11-08 (Wtorek)
Zapraszamy do sali 1.03, ul. Pasteura 5 o godzinie 18:30
Ryszard Kutner (Wydział Fizyki UW)The Concept of the Continuous Multicritical Phenomena in Complex Systems: Agent-Based Modeling of the Company Market
In response to the everyday empirical observations of complex systems, we developed an approach in which many different critical phenomena can coexist. We found this coexistence in the non-equilibrium multicritical continuous phase transitions for partial stationary acrostates in an agent-based simulation model. Each multicritical point belongs to the 1-manifold and is assigned with the continuous spectrum of critical exponents (except the spectrum discontinuity at border/marginal exponents). It applies to both primary and secondary statistics/characteristics. It is a novel look at the universality, which we call continuous multicriticality.join us via zoomhttps://us02web.zoom.us/j/82025295160?pwd=Rno0Skx6Q3haRzVzZy90dkRrbmxQQT09Meeting ID: 820 2529 5160Passcode: 794269