Imre Varga

University of Debrecen · Department of Informatics Systems and Networks

Mass transportation networks of cities or regions are interesting and important to be studied to get a picture of the properties of a somehow better topology and system of transportation. One way to do this lies on the basis of spatial information of stations and routes. As we show however interesting findings can be gained also if one studies the...

Objectives: The COVID-19 pandemic is considered a major threat to global public health. The aim of our study was to use the official epidemiological data to forecast the epidemic curves (daily new cases) of the COVID-19 using Artificial Intelligence (AI)-based Recurrent Neural Networks (RNNs), then to compare and validate the predicted models with...

Objectives: The current form of severe acute respiratory syndrome called coronavirus disease 2019 (COVID19) caused by a coronavirus (SARSCoV2) is a major global health problem. The aim of our study was to use the official data and predict the possible outcomes of the COVID 19 pandemic using artificial intelligence (AI) based RNNs (Recurrent Neural...

Main issues of the Big Data processing imply high speed transmission between different nodes of the infocommunication system. Best effort based datagram delivery of the protocol data units requires bandwidth in the scale of n*10 Mb/s for time critical services. Although IntServ and DiffServ QoS mechanisms make possible for time critical data flows...

Faults and damage zone properties control a range of important phenomena, from the hydraulic properties of underground reservoirs to the physics of earthquakes on a larger scale. Here, we investigate the effect of disorder of porous rocks on the spatial structure of damage emerging under compression. Model rock samples are numerically generated by...

A model of agent-based simulation of communicating vehicles is presented to study the information spreading in a vehicular ad hoc network (VANET). The agents are moving along the fastest paths between their starting points and their destinations on real urban topo-logy. During the motion, they can exchange information by short-range wireless commun...

In several real networks large heterogeneity of links is present either in intensity or in the nature of relationships. Therefore, recent studies in network science indicate that more detailed topological information are available if weighted or multi-layer aspect is applied. In the age of globalization air transportation is a representative exampl...

In this paper I propose a novel method to model real online social networks where the growing scale-free networks have tunable clustering coefficient independently of the average degree and the exponent of the degree distribution. Models based on purely preferential attachment are not able to describe high clustering coefficient of social networks....

We propose a novel method to generate scale-free networks with discretely tunable clustering coefficient in order to model real social networks. Recently several methods were introduced to generate networks with power law degree distribution. Most of them are based on preferential attachment, but in these networks the average clustering coefficient...

In this work a novel model of spreading processes is presented. The model is an upgrade of a previously introduced model of information spreading [1]. Here we take into account that agents of the system are not always active during the spreading and information can flow only through those that are currently active. In order to suit our work to othe...

The most important characteristics of the fragmentation of heterogeneous solids is that the mass (size) distribution of pieces is described by a power law functional form. The exponent of the distribution displays a high degree of universality depending mainly on the dimensionality and on the brittle-ductile mechanical response of the system. Recen...

In this work a novel model of information spreading processes in systems of dynamic active-inactive actors is presented. In our model information can flow only through those actors of the system that are currently active. Based on this model we carried out computer simulations showing how the activity of agents affect the process. We also carried o...

In this paper the results of our investigations related to social spreading are summed up and concluded. In our work we studied information spreading on different network topologies. Based on a novel complex network generating method we managed to generate several test cases for social simulations focusing mainly on the case of declining socia...

In this paper we aim to investigate the question if it's worth it to advertise on declining social networks or not. Our investigations are based on computer simulations using a previously defined and here simplified model of information spreading. To make our results as close to the real life as possible we run simulations both on a real network sa...

We investigate the scaling properties of the sources of crackling noise in a fully dynamic numerical model of sedimentary rocks subject to uniaxial compression. The model is initiated by filling a cylindrical container with randomly sized spherical particles that are then connected by breakable beams. Loading at a constant strain rate the cohesive...

We propose a method of generating different scale-free networks, which has several input parameters in order to adjust the structure, so that they can serve as a basis for computer simulation of real-world phenomena. The topological structure of these networks was studied to determine what kind of networks can be produced and how can we give the ap...

We investigate the approach to catastrophic failure in a model porous granular material undergoing uniaxial compression. A discrete element computational model is used to simulate both the microstructure of the material and the complex dynamics and feedbacks involved in local fracturing and the production of crackling noise. Under strain-controlled...

We study the impact fragmentation of two-and three-dimensional disordered solids in a discrete element model of heterogeneous brittle materials focusing on the spatial distribution and mass-velocity correlation of fragments. Our calculations revealed that depending on the energy of impact the breakup process can have two different outcomes: at low...

We present a discrete element model of geomaterials and investigate the uniaxial compression of cylindrical specimens. In order to capture the heterogeneous micro-structure of materials the sample is generated by sedimenting randomly sized spherical particles inside a cylindrical container. The cohesive interaction of particles is represented by be...

We present a detailed experimental study of the aggregation of particles of permanent magnetic moment in an external magnetic field. The experiments are performed with millimeter-sized particles floating on the surface of water. Due to the large size of the particles, thermal noise does not have any relevance in the system; the particles undergo de...

The attraction-limited cluster—cluster aggregation of two-dimensional Ising dipolar particles with or without particle-size dispersity is studied. The fast decrease of the number of even-sized clusters for relatively smaller clusters is observed. Furthermore, it is suggested that, even in the dilute limit, the dynamic exponents are affected by the...

We show that in binary dipolar monolayers (BDM) crystalline states, analogous to colloidal molecular crystals observed in colloids interacting with a periodic array of traps, can emerge without the application of an underlying substrate. The n-mers of BDMs are bounded configurations of particles with oppositely oriented permanent dipoles. Brownian...

We present an experimental study of the kinetic and structural aspects of heteroaggregation in binary dipolar monolayers. Particles of the two components of the system have oppositely oriented dipole moments constrained to be perpendicular to the plane of motion. We show experimentally that growing clusters have chain-like morphology with a crossov...

An experimental and theoretical study of the formation of structures in a binary monolayer of dipolar particles is presented. We construct an experimental technique for an easy to control realization of a binary monolayer where the two components have oppositely oriented dipole moments constrained perpendicular to the plane of motion. The experimen...

The attraction-limited cluster-cluster aggregation of two-dimensional Ising dipolar particles with or without particle-size dispersity is studied. The fast decrease of the number of even-sized clusters for relatively smaller clusters is observed. The threshold concentration is also determined, under which the dynamics of aggregation is explained us...

We propose an experimental technique for an easy to control realization of a binary dipolar monolayer where the two components have oppositely oriented dipole moments constrained perpendicular to the plane of motion without the application of an external field. The experimental setup ensures that hydrodynamic effects do not play a crucial role in t...

A theoretical study of the structure formation observed very recently [W. D. Ristenpart, I. A. Aksay, and D. A. Saville, Phys. Rev. Lett. 90, 128303 (2003)] in binary colloids is presented. In our model solely the dipole-dipole interaction of the particles is considered, electrohydrodynamic effects are excluded. Based on molecular dynamics simulati...

We present a variant of the recently developed void expansion method (VEM) to generate random heterogeneous materials with a highly porous micro-structure. A polydisperse mixture of structural and void particles is generated by gradually expanding randomly placed initially point-like objects. Computer simulations revealed that varying the volume fr...

Rendezetlen mikroszkópikus tulajdonságokkal rendelkező anyagok törési folyamatát vizsgáltuk konstans és periódikusan változó külső terhelés alatt. Megmutattuk, hogy a makroszkópikus törés kritikus időpontjához közeledve a rendszert univerzális skálatörvények jellemzik, amelyek felhasználhatóak a makroszkópikus törés előrejelzésére is. A creep és fa...