Search results for "entropy"
showing 10 items of 496 documents
Modelling urban networks sustainable progress
2019
In this paper, we analyse the relations between thermodynamics and city networks: an increase in the complexity and the organized information in such urban systems leads to less demand for resources and less social entropy, which overall makes them more efficient and stable. The goal of this study is to propose a method to measuring city networks sustainable progress based on statistical models, derived from Eurostat databases and NASA satellite images, and capable of analyzing different conceptual scenarios of urban development in Europe. The obtained probability-based indices enable us to evaluate the dynamics of city networks in terms of three components of sustainable progress – economi…
Quantification and automatized adaptive detection of in vivo and in vitro neuronal bursts based on signal complexity.
2015
In this paper, we propose employing entropy values to quantify action potential bursts in electrophysiological measurements from the brain and neuronal cultures. Conventionally in the electrophysiological signal analysis, bursts are quantified by means of conventional measures such as their durations, and number of spikes in bursts. Here our main aim is to device metrics for burst quantification to provide for enhanced burst characterization. Entropy is a widely employed measure to quantify regularity/complexity of time series. Specifically, we investigate the applicability and differences of spectral entropy and sample entropy in the quantification of bursts in in vivo rat hippocampal meas…
An Information-Theoretic Framework to Measure the Dynamic Interaction between Neural Spike Trains
2021
Understanding the interaction patterns among simultaneous recordings of spike trains from multiple neuronal units is a key topic in neuroscience. However, an optimal approach of assessing these interactions has not been established, as existing methods either do not consider the inherent point process nature of spike trains or are based on parametric assumptions that may lead to wrong inferences if not met. This work presents a framework, grounded in the field of information dynamics, for the model-free, continuous-time estimation of both undirected (symmetric) and directed (causal) interactions between pairs of spike trains. The framework decomposes the overall information exchanged dynami…
2020
Abstract Background and objective Deep learning approaches are common in image processing, but often rely on supervised learning, which requires a large volume of training images, usually accompanied by hand-crafted labels. As labelled data are often not available, it would be desirable to develop methods that allow such data to be compiled automatically. In this study, we used a Generative Adversarial Network (GAN) to generate realistic B-mode musculoskeletal ultrasound images, and tested the suitability of two automated labelling approaches. Methods We used a model including two GANs each trained to transfer an image from one domain to another. The two inputs were a set of 100 longitudina…
Maximizing reading: pattern analysis to describe points of gaze
2006
As people read texts, their points of gaze can be described either as a sequence or as a pattern of dots. If reading fixations are visualized as a pattern and their duration is graphically attributed to the 3 rd dimension, image processing techniques can be employed to describe individual reading styles. Two reader groups of text editors and of University students were matching according to parametric tests. Yet they appeared to have marked inter-subject variability of fixation distribution when individual cases were considered. To illustrate this, we applied a simple "Coulomb law" - like model that takes both fixation duration and spacing into account. Further the image entropy filter was …
Spatial/spectral information trade-off in hyperspectral images
2015
This paper shows an empirical analysis of the trade-off between the spectral and the spatial information content of hyperspectral images. The objective of this study is to provide some insights into how changes and variations of both resolutions may affect the information content of the resulting image. This is useful for different stages of hyperspectral image processing: from acquisition to final applications. We propose two alternative approaches to measure the information content of a hyperspectral image: first, a second order approximation where the data distribution is supposed to be Gaussian, and secondly a higher order approximation where no assumption about the data distribution is…
Small worlds with a difference
2011
Political discussions on social network platforms represent an increasingly relevant source of political information, an opportunity for the exchange of opinions and a popular source of quotes for media outlets. We analyzed political communication on Twitter during the run-up to the German general election of 2009 by extracting a directed network of user interactions based on the exchange of political information and opinions. In consonance with expectations from previous research, the resulting network exhibits small-world properties, lending itself to fast and efficient information diffusion. We go on to demonstrate that precisely the highly connected nodes, characteristic for small-world…
Diversity in random subspacing ensembles
2004
Ensembles of learnt models constitute one of the main current directions in machine learning and data mining. It was shown experimentally and theoretically that in order for an ensemble to be effective, it should consist of classifiers having diversity in their predictions. A number of ways are known to quantify diversity in ensembles, but little research has been done about their appropriateness. In this paper, we compare eight measures of the ensemble diversity with regard to their correlation with the accuracy improvement due to ensembles. We conduct experiments on 21 data sets from the UCI machine learning repository, comparing the correlations for random subspacing ensembles with diffe…
Peculiarities of the local structure in new medium- and high-entropy, low-symmetry tungstates
2022
G. Bakradze acknowledges financial support provided by the Latvian Council of Science for project no. 1.1.1.2/VIAA/3/19/444 (agreement no. 1.1.1.2/16/I/001) realized at the Institute of Solid State Physics, University of Latvia. The Institute of Solid State Physics, University of Latvia, as a centre of excellence, has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement no. 739508, project CAMART2.
Thermodynamic properties at the phase transition of Pb(Zr, Sn, Ti)O3solid solutions
2000
Abstract Field induced deformation and electrocaloric effect are investigated in the vicinity of phase transition at 163°C. The sharp increase of electrostriction below Tc is explained by the field induced ferroelectric to antiferroelectric phase transition. The antiferroelectric phase appears and remains stable below Tc in the absence of field. Elastic compliance and thermal expansion as functions of temperature are studied.