December 2022 - semfis - Mailing lists@ IFISC

Reminder: Talk, TODAY - Thursday, Dec 15, 2022 at 14:30
by semfis＠ifisc.uib-csic.es 15 Dec '22

15 Dec '22

Talk on Thursday Dec 15, 2022 at 14:30 Place: IFISC Seminar Room Title: A method for detecting and quantifying information transmission biases in complex networks Speaker: Fernando Diaz, IFISC (CSIC-UIB) Abstract: Abstract: Social networks play a major role in the transmission of information between individuals. However, one key issue of this way of transmitting information is that it can be biased: the network structure may cause some individuals to have a disproportionate visibility, hinder the communication between members in different opinion groups and so on, leading to dangerous consequences for the democratic discourse and our society in general. Despite the ubiquity of these biases however, a unified theory able to detect which ones are present in a given network and help mitigate their effects is still missing. In this work, we propose a simple method able to isolate and quantify the information transmission biases present in any network. This method is based on an orthogonal decomposition of a graph into an average component plus a set of bias variables. We explore some mathematical properties of these variables, and propose a diagrammatic representation that captures the key properties of eac h bias in an intuitive way. Our method sheds light into the structural inequalities arising in widely different systems, such as political communities on Twitter, linguistic communities in multicultural cities or scientific citations networks. Url event:https://ifisc.uib-csic.es/en/events/seminars/a-method-for-detecting-and-quantifying-information/

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Reminder: IFISC Seminar, TODAY - Wednesday, Dec 14, 2022 at 14:30
by semfis＠ifisc.uib-csic.es 14 Dec '22

14 Dec '22

IFISC Seminar on Wednesday Dec 14, 2022 at 14:30 Place: Zoom Seminar Title: Learning force fields from stochastic trajectories Speaker: Anna Frishman , Technion Israel, Department of Physics Abstract: Particles in biological and soft matter systems undergo Brownian dynamics: their deterministic motion, induced by forces, competes with random diffusion due to thermal noise. More broadly, Brownian dynamics is a generic and simple model for dynamical systems with fast degrees of freedom modeled as noise. &nbsp; Provided only with the time-series of positions of such a system, i.e. a trajectory in phase space, it is challenging to infer what force field had produced it. At the same time, knowledge of the force field is key to characterize the dynamical system. I will discuss the information about the force field contained in the trajectory and present a bound on the rate at which it can be extracted. I will then present a practical method, Stochastic Force Inference, that optimally uses this information to approximate force fields. This technique also permits the evaluation of out-of-equilibrium currents and entropy production, as well as diffusion coefficients. Zoom link: https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09</span… &nbsp; &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/learning-force-fields-from-stochastic-trajectories/

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Reminder: Talk, TODAY - Tuesday, Dec 13, 2022 at 15:00
by semfis＠ifisc.uib-csic.es 13 Dec '22

13 Dec '22

Talk on Tuesday Dec 13, 2022 at 15:00 Place: Zoom Seminar Title: Integrated optical output layer for a reservoir computer based on frequency multiplexing Speaker: Tigers Jonuzi, VLC Photonics Abstract: Reservoir Computing (RCs) is a brain-inspired computational paradigm based on recurrent neural networks where only output weights are tuned, while internal weights remain untrained. Recently, a photonic RC system that encodes neurons in the lines of a frequency comb was demonstrated. A similar frequency-multiplexing approach was used to implement a single-layer feed-forward neural network. Here, we present the design for an integrated optical output layer for such frequency based photonic neural networks. The all-optical output layer uses wavelength (de)multiplexers and wavelength converters to apply signed weights to neurons encoded in comb lines. The design concept has been split in two integrated circuits comprehending a Silicon Photonic technology for the weighting scheme and an Indium Phosphide platform for the non-linear optical operation. During this talk, simulations and design parameters will be presented and discussed in detail. Zoom link:&nbsp;<a href="https://uibuniversitat.zoom.us/j/87008849910">https://uibuniversitat.zoom.us/j/87008849910</a> Meeting ID: 870 0884 9910 Url event:https://ifisc.uib-csic.es/en/events/seminars/integrated-optical-output-layer-for-a-reservoir-co/

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Reminder: Master Thesis, TODAY - Monday, Dec 12, 2022 at 15:00
by semfis＠ifisc.uib-csic.es 12 Dec '22

12 Dec '22

Master Thesis on Monday Dec 12, 2022 at 15:00 Place: Zoom Seminar Title: Functional networks of weather events propagation between airports Speaker: Raúl López Martín, IFISC / UIB Abstract: Meteorology and climatology are fields of great relevance, not only from a purely scientific point of view, but also as they affect everyday life. Hence, gaining a deeper understanding on these areas is necessary. In this project, to do so, the novel functional networks approach is going to be followed to understand the spatial and temporal propagation of three meteorological variables: temperature, difference between temperature, and dew point and wind speed. To do so, first their associated time series are going to be extracted from airport meteorological reports for 249 airports from 2019 to 2022. Then, after time series are reconstructed, causality relations are going to be checked between time series of the same variable at different spatial locations, using Granger causality. Finally, complex networks are going to be built where nodes are the spatial locations, and an edge exists between two nodes if a causality is found between them. An analysis of the results will allow us to make hypothesis about the physical phenomena underlying the found causalities and determine strong points and limitations of the methodology. Finally, further work for this project, both from a methodological and applicational point of view, will be commented. Supervisor: Massimiliano Zanin Jury: Jose Javier Ramasco,&nbsp;Sandro Meloni,&nbsp;Massimiliano Zanin &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/functional-networks-of-weather-events-propagation/

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Talk on Tuesday, Dec 13, 2022 at 15:00
by semfis＠ifisc.uib-csic.es 09 Dec '22

09 Dec '22

Talk on Tuesday Dec 13, 2022 at 15:00 Place: Zoom Seminar Title: Integrated optical output layer for a reservoir computer based on frequency multiplexing Speaker: Tigers Jonuzi, VLC Photonics Abstract: Reservoir Computing (RCs) is a brain-inspired computational paradigm based on recurrent neural networks where only output weights are tuned, while internal weights remain untrained. Recently, a photonic RC system that encodes neurons in the lines of a frequency comb was demonstrated. A similar frequency-multiplexing approach was used to implement a single-layer feed-forward neural network. Here, we present the design for an integrated optical output layer for such frequency based photonic neural networks. The all-optical output layer uses wavelength (de)multiplexers and wavelength converters to apply signed weights to neurons encoded in comb lines. The design concept has been split in two integrated circuits comprehending a Silicon Photonic technology for the weighting scheme and an Indium Phosphide platform for the non-linear optical operation. During this talk, simulations and design parameters will be presented and discussed in detail. Zoom link:&nbsp;<a href="https://uibuniversitat.zoom.us/j/87008849910">https://uibuniversitat.zoom.us/j/87008849910</a> Meeting ID: 870 0884 9910 Url event:https://ifisc.uib-csic.es/en/events/seminars/integrated-optical-output-layer-for-a-reservoir-co/

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Master Thesis on Monday, Dec 12, 2022 at 15:00
by semfis＠ifisc.uib-csic.es 09 Dec '22

09 Dec '22

Master Thesis on Monday Dec 12, 2022 at 15:00 Place: Zoom Seminar Title: Functional networks of weather events propagation between airports Speaker: Raúl López Martín, IFISC / UIB Abstract: Meteorology and climatology are fields of great relevance, not only from a purely scientific point of view, but also as they affect everyday life. Hence, gaining a deeper understanding on these areas is necessary. In this project, to do so, the novel functional networks approach is going to be followed to understand the spatial and temporal propagation of three meteorological variables: temperature, difference between temperature, and dew point and wind speed. To do so, first their associated time series are going to be extracted from airport meteorological reports for 249 airports from 2019 to 2022. Then, after time series are reconstructed, causality relations are going to be checked between time series of the same variable at different spatial locations, using Granger causality. Finally, complex networks are going to be built where nodes are the spatial locations, and an edge exists between two nodes if a causality is found between them. An analysis of the results will allow us to make hypothesis about the physical phenomena underlying the found causalities and determine strong points and limitations of the methodology. Finally, further work for this project, both from a methodological and applicational point of view, will be commented. Supervisor: Massimiliano Zanin Jury: Jose Javier Ramasco,&nbsp;Sandro Meloni,&nbsp;Massimiliano Zanin &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/functional-networks-of-weather-events-propagation/

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IFISC Seminar on Wednesday, Dec 14, 2022 at 14:30
by semfis＠ifisc.uib-csic.es 09 Dec '22

09 Dec '22

IFISC Seminar on Wednesday Dec 14, 2022 at 14:30 Place: Zoom Seminar Title: Learning force fields from stochastic trajectories Speaker: Anna Frishman , Technion Israel, Department of Physics Abstract: Particles in biological and soft matter systems undergo Brownian dynamics: their deterministic motion, induced by forces, competes with random diffusion due to thermal noise. More broadly, Brownian dynamics is a generic and simple model for dynamical systems with fast degrees of freedom modeled as noise. &nbsp; Provided only with the time-series of positions of such a system, i.e. a trajectory in phase space, it is challenging to infer what force field had produced it. At the same time, knowledge of the force field is key to characterize the dynamical system. I will discuss the information about the force field contained in the trajectory and present a bound on the rate at which it can be extracted. I will then present a practical method, Stochastic Force Inference, that optimally uses this information to approximate force fields. This technique also permits the evaluation of out-of-equilibrium currents and entropy production, as well as diffusion coefficients. Zoom link: https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09</span… &nbsp; &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/learning-force-fields-from-stochastic-trajectories/

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Reminder: Talk, TODAY - Wednesday, Dec 07, 2022 at 14:30
by semfis＠ifisc.uib-csic.es 07 Dec '22

07 Dec '22

Talk on Wednesday Dec 07, 2022 at 14:30 Place: IFISC Seminar Room Title: Time evolution of signed networks sparkling with conflicts Speaker: Paride Crisafulli, IFISC Abstract: The&nbsp;Fireworks Model&nbsp;describes the behavior and the time-evolution of signed networks generated by two-sided conflicts. We assumed that links form ex-novo at each step and decay in the next one, making it unnecessary to study the actual edge-dynamics. If this assumption holds, our model reduces the study of these networks to a series of sampling problems. We tested the model on two different datasets: the USPTO patent-litigation dataset and an Interstate-War dataset. We focused on reproducing the main features of the networks, with particular regard to the largest connected component&nbsp;and the number of triangles. &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/time-evolution-of-signed-networks-sparkling-with-c/

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Talk on Wednesday, Dec 07, 2022 at 14:30
by semfis＠ifisc.uib-csic.es 02 Dec '22

02 Dec '22

Talk on Wednesday Dec 07, 2022 at 14:30 Place: IFISC Seminar Room Title: Time evolution of signed networks sparkling with conflicts Speaker: Paride Crisafulli, IFISC Abstract: The&nbsp;Fireworks Model&nbsp;describes the behavior and the time-evolution of signed networks generated by two-sided conflicts. We assumed that links form ex-novo at each step and decay in the next one, making it unnecessary to study the actual edge-dynamics. If this assumption holds, our model reduces the study of these networks to a series of sampling problems. We tested the model on two different datasets: the USPTO patent-litigation dataset and an Interstate-War dataset. We focused on reproducing the main features of the networks, with particular regard to the largest connected component&nbsp;and the number of triangles. &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/time-evolution-of-signed-networks-sparkling-with-c/

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