1. Interlayer connectivity affects the coherence resonance and population activity patterns in two-layered networks of excitatory and inhibitory neuronsDavid Ristič, Marko Gosak, 2022, original scientific article Abstract: The firing patterns of neuronal populations often exhibit emergent collective oscillations, which can display substantial regularity even though the dynamics of individual elements is very stochastic. One of the many phenomena that is often studied in this context is coherence resonance, where additional noise leads to improved regularity of spiking activity in neurons. In this work, we investigate how the coherence resonance phenomenon manifests itself in populations of excitatory and inhibitory neurons. In our simulations, we use the coupled FitzHugh-Nagumo oscillators in the excitable regime and in the presence of neuronal noise. Formally, our model is based on the concept of a two-layered network, where one layer contains inhibitory neurons, the other excitatory neurons, and the interlayer connections represent heterotypic interactions. The neuronal activity is simulated in realistic coupling schemes in which neurons within each layer are connected with undirected connections, whereas neurons of different types are connected with directed interlayer connections. In this setting, we investigate how different neurophysiological determinants affect the coherence resonance. Specifically, we focus on the proportion of inhibitory neurons, the proportion of excitatory interlayer axons, and the architecture of interlayer connections between inhibitory and excitatory neurons. Our results reveal that the regularity of simulated neural activity can be increased by a stronger damping of the excitatory layer. This can be accomplished with a higher proportion of inhibitory neurons, a higher fraction of inhibitory interlayer axons, a stronger coupling between inhibitory axons, or by a heterogeneous configuration of interlayer connections. Our approach of modeling multilayered neuronal networks in combination with stochastic dynamics offers a novel perspective on how the neural architecture can affect neural information processing and provide possible applications in designing networks of artificial neural circuits to optimize their function via noise-induced phenomena.
Keywords: neuronal dynamics, coherence resonance, excitatory neurons, inhibitory neurons, neural network, multilayer network, interlayer connectivity
Published in DKUM: 20.12.2024; Views: 0; Downloads: 4
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2. Intelligent system for prediction of mechanical properties of material based on metallographic imagesMatej Paulič, David Močnik, Mirko Ficko, Jože Balič, Tomaž Irgolič, Simon Klančnik, 2015, original scientific article Abstract: This article presents developed intelligent system for prediction of mechanical properties of material based on metallographic images. The system is composed of two modules. The first module of the system is an algorithm for features extraction from metallographic images. The first algorithm reads metallographic image, which was obtained by microscope, followed by image features extraction with developed algorithm and in the end algorithm calculates proportions of the material microstructure. In this research we need to determine proportions of graphite, ferrite and ausferrite from metallographic images as accurately as possible. The second module of the developed system is a system for prediction of mechanical properties of material. Prediction of mechanical properties of material was performed by feed-forward artificial neural network. As inputs into artificial neural network calculated proportions of graphite, ferrite and ausferrite were used, as targets for training mechanical properties of material were used. Training of artificial neural network was performed on quite small database, but with parameters changing we succeeded. Artificial neural network learned to such extent that the error was acceptable. With the oriented neural network we successfully predicted mechanical properties for excluded sample.
Keywords: artificial neural network, factor of phase coherence between the surfaces, fracture toughness, image processing, mechanical properties, metallographic image, ultimate tensile strength, yield strength
Published in DKUM: 12.07.2017; Views: 1554; Downloads: 437
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3. Autapse-induced multiple coherence resonance in single neurons and neuronal networksErgin Yilmaz, Mahmut Özer, Veli Baysal, Matjaž Perc, 2016, original scientific article Abstract: We study the effects of electrical and chemical autapse on the temporal coherence or firing regularity of single stochastic Hodgkin-Huxley neurons and scale-free neuronal networks. Also, we study the effects of chemical autapse on the occurrence of spatial synchronization in scale-free neuronal networks. Irrespective of the type of autapse, we observe autaptic time delay induced multiple coherence resonance for appropriately tuned autaptic conductance levels in single neurons. More precisely, we show that in the presence of an electrical autapse, there is an optimal intensity of channel noise inducing the multiple coherence resonance, whereas in the presence of chemical autapse the occurrence of multiple coherence resonance is less sensitive to the channel noise intensity. At the network level, we find autaptic time delay induced multiple coherence resonance and synchronization transitions, occurring at approximately the same delay lengths. We show that these two phenomena can arise only at a specific range of the coupling strength, and that they can be observed independently of the average degree of the network.
Keywords: neuronal dynamics, autapse, coherence resonance, scale-free network
Published in DKUM: 23.06.2017; Views: 1163; Downloads: 447
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4. Harold Pinter in Slovene translationsDarja Darinka Hribar, 2004, original scientific article Abstract: This article examines the translation of Harold Pinter's most notable stylistic peculiarities into Slovene, illustrating its main points with examples taken from his play The Homecoming. The findings demonstrate above all a marked degree of non-observance of the special verbal pattern (special cohesion) of the originals, a failure to convey Pinter's special configuration of meaning (special coherence), and a disregard for internal unifying coincidences. It argues that the Slovene translations of Pinter rely mostly on traditional theories of meaning and of language norms, thus preventing the reproduction of those emotional and psychological actions of Pinter's characters which are usually not expressed by means of the rhetorical, informative elements of his dialogue, but by its form and sonority, i. e. the length, strength, and level of articulation of verbal expression. This blurs Pinter's famous logic of emotion, narrows the proverbial openness and conceptual uncertainty of his plays, and limits their potential vitality in translation. Taking into account current drama and theatre translation practices in Slovenia, i.e. the rarity of published drama translation and the depedence on a translated performance text for subsequent theatrical productions, the article argues that in such cases the drama translation should be retrospective, i.e. aiming at a maximum reconstruction of all relevant linguistic, stylistic, and textual properties of the original, leaving expressly subjective interventions in the text to the theatre practitioners.
Keywords: English literature, drama, translation, theory of translation, translation of beletristics, cohesion, coherence, comparative analyses, drama translations
Published in DKUM: 16.05.2017; Views: 1775; Downloads: 173
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5. Discourse Characteristics of Self-Help Books: The Example of The 7 Habits of Highly Effective People by Stephen R. CoveyTamara Nerat, 2017, master's thesis Abstract: The main purpose of the thesis was to explore the discourse characteristics in self-help books on the example of a popular classic of this genre. The aim was a discourse analysis of the self-help manual The 7 Habits of Highly Effective People (1989) by Stephen R. Covey. The book falls under the self-help category and includes typical features which are common for the genre. The thesis presents the distinguishing characteristics and shows the conventions which make it a typical representative of its genre. The main part consists of a discourse analysis of a chapter from the book, discussing the prevailing cohesive relations and its situational and generic coherence. The analysis examines the following cohesive devices: reference chains, typical examples of ellipsis and substitution, conjunction (the use of linking words and lexical ties), typical examples of lexical cohesion (examples of reiteration). The practical value of discourse analysis is in the fact that it displays a text's cohesion and coherence, both of which impact the text's quality and show if a text makes sense as a unified whole. The knowledge of cohesive devices is useful for evaluating texts (helping readers, critics, teachers) and text production (helping writers, journalists, students). The analysis has demonstrated connectedness and unity achieved through the use of cohesive devices and the prevalence of certain cohesive devices which can be linked to the specifics of the genre. The analysis also shows a situational and generic coherence, that is in line with the expectations towards the genre and context. An insight into how the internal organization of the text and content is connected to the register and genre of the text is supplied by the conclusion based on the analysis.
Keywords: discourse, cohesion, cohesive devices, coherence, register, genre, self-help, Stephen R. Covey, self-improvement, habits
Published in DKUM: 20.02.2017; Views: 2864; Downloads: 264
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6. Intelligence-related differences in induced gamma band activityNorbert Jaušovec, 2004, published scientific conference contribution abstract Keywords: psychology, intelligence, emotional intelligence, coherence, desynchronization, EEG, event-related coherence, event-related desynchronization, cognitive precesses, neural efficiency, memory processes, perception
Published in DKUM: 07.06.2012; Views: 1909; Downloads: 31
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7. Differences in induced brain activity related to creativityNorbert Jaušovec, 2004, published scientific conference contribution abstract Keywords: psychology, intelligence, emotional intelligence, coherence, desynchronization, EEG, event-related coherence, event-related desynchronization, cognitive precesses, neural efficiency, memory processes, perception
Published in DKUM: 07.06.2012; Views: 1750; Downloads: 45
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8. Proximity to periodic windows in bifurcation diagrams as a gateway to coherence resonance in chaotic systemsMarko Gosak, Matjaž Perc, 2007, original scientific article Abstract: We show that chaotic states situated in the proximity of periodic windows in bifurcation diagrams are eligible for the observation of coherence resonance. In particular, additive Gaussian noise of appropriate intensity can enhance the temporal order in such chaotic states in a resonant manner. Results obtained for the logistic map and the Lorenz equations suggest that the presented mechanism of coherence resonance is valid beyond particularities of individual systems. We attribute the findings to the increasing attraction of imminent periodic orbits and the ability of noise to anticipate their existence and use a modified wavelet analysis to support our arguments.
Keywords: chaotic systems, spatial resonance, coherence resonance, nonlinear systems, noise, spatial dynamics, mathematical models, bifurcation diagrame
Published in DKUM: 07.06.2012; Views: 2407; Downloads: 143
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9. Spatial coherence resonance in excitable biochemical media induced by internal noiseMarko Gosak, Marko Marhl, Matjaž Perc, 2007, original scientific article Abstract: We show that in a spatially extended excitable medium, presently modelled with diffusively coupled FitzHugh-Nagumo neurons, internal stochasticity is able to extract a characteristic spatial frequency of waves on the spatial grid. Internal noise is introduced via a stochastic simulation method and is the only agent acting on the system. Remarkably, the spatial periodicity is best pronounced at an intermediate level of internal stochasticity. Thus, the reported phenomenon is an observation of internal noise spatial coherence resonance in excitable biochemical media.
Keywords: noise, spatiotemporal noise, intensity, spatial resonance, spatial coherence resonance, excitable media, excitable biochemical media, neuronal dynamics, internal noise
Published in DKUM: 07.06.2012; Views: 1735; Downloads: 85
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