Illés Horváth

ORCID: 0000-0003-2724-1851
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Research Areas
  • Advanced Queuing Theory Analysis
  • Markov Chains and Monte Carlo Methods
  • Matrix Theory and Algorithms
  • Stochastic processes and statistical mechanics
  • Simulation Techniques and Applications
  • Distributed and Parallel Computing Systems
  • Theoretical and Computational Physics
  • Complex Network Analysis Techniques
  • Time Series Analysis and Forecasting
  • Opinion Dynamics and Social Influence
  • Network Traffic and Congestion Control
  • Cloud Computing and Resource Management
  • Probability and Risk Models
  • Statistical Distribution Estimation and Applications
  • Advanced Wireless Network Optimization
  • Stochastic processes and financial applications
  • Software-Defined Networks and 5G
  • Distributed systems and fault tolerance
  • Numerical methods for differential equations
  • Financial Risk and Volatility Modeling
  • COVID-19 epidemiological studies
  • Complex Systems and Time Series Analysis
  • Graph theory and applications
  • Petri Nets in System Modeling
  • Data Visualization and Analytics

Budapest University of Technology and Economics
2009-2023

Institute for Computer Science and Control
2018

Universidad EAFIT
2014

We investigate local-density dependent Markov processes on a class of large graphs sampled from graphon, where the transition rates vertices are influenced by states their neighbors. show that as average degree converges to infinity (faster than given threshold), evolution process in transient regime solution set non-local integro-partial differential equations depending limit graphon. also provide rigorous derivation for epidemic threshold case Susceptible–Infected–Susceptible (SIS) such graphons.

10.1016/j.spa.2022.03.001 article EN cc-by-nc-nd Stochastic Processes and their Applications 2022-03-09

This paper presents matrix-exponential (ME) distributions, whose squared coefficient of variation (SCV) is very low. Currently, there no symbolic construction available to obtain the most concentrated ME and numerical optimization-based approaches construct them have many pitfalls. We present a procedure which avoids issues.

10.1080/15326349.2019.1702058 article EN cc-by Stochastic Models 2019-12-18

10.1016/j.cam.2022.114651 article EN Journal of Computational and Applied Mathematics 2022-08-03

We propose a numerical inverse Laplace transformation method without overshoot which is derived from matrix exponential (ME) distributions with minimal coefficient of variation. discuss the properties through an integral based interpretation methods belonging to Abate–Whitt framework. Compared previously applied non-overshooting alternative, "Erlang" method, error proposed improves O(1/n) O(1/n2) while it maintains same computational complexity.

10.1016/j.entcs.2018.03.035 article EN Electronic Notes in Theoretical Computer Science 2018-05-01

In this paper, we investigate dimension reduction possibilities of multidimensional time series data and introduce a graph based clustering approach using the cross-correlation between series. The proposed solution consists two main steps: introducing novel similarity measure for measuring cross-correlations graph-based technique. These parts are both compared to existing techniques, including noise tolerance our performs better in noisy environment. is applied performance metrics specific...

10.1109/ines.2017.8118563 article EN 2017-10-01

10.1016/j.dam.2010.11.016 article EN publisher-specific-oa Discrete Applied Mathematics 2010-12-16

Load balancing plays a crucial role in many large scale computer systems. Much prior work has focused on systems with First-Come-First-Served (FCFS) servers. However, servers practical are more complicated. They serve multiple jobs at once, and their service rate can depend the number of service. Motivated by this, we study load for using Limited-Processor-Sharing (LPS). Our model heterogeneous servers, meaning curve multiprogramming level (limit sharing processor) differs between We focus...

10.1145/3366705 article EN Proceedings of the ACM on Measurement and Analysis of Computing Systems 2019-12-17

Numerical inverse Z-transformation (NIZT) methods have been efficiently used in engineering practice for a long time. In this paper, we compare the abilities of most widely NIZT methods, and propose new variant classic method based on contour integral approximation, which is efficient when point interest (at value function needed) smaller than order method. We also introduce vastly different concentrated matrix geometric (CMG) distributions that tackles limitations many larger

10.3390/math8040556 article EN cc-by Mathematics 2020-04-10

The paper presents a new proof of O'Cinneide's characterization theorem.[7 O'Cinneide, C.A. Characterization phase-type distributions. Comm. Stat. Stochastic Models 1990, 6, 1–57.[Taylor & Francis Online] , [Google Scholar]] It is much simpler than the original one and constructive in sense that we not only show existence phase type representation, but present procedure which creates representation. We prove succeeds when conditions theorem hold.

10.1080/15326349.2015.1012912 article EN Stochastic Models 2015-04-03

In spite of the fact that discrete phase type (DPH) distributions are used almost as often continuous (CPH) canonical representation is not available for general (cyclic) order 3 DPH yet. this paper we investigate 3. During course investigation find problem far more complex than one CPH distribution. As a result needed to distinguish 8 different subclasses distributions, while it was enough their representation. Additionally, were able prove all with relatively simple methodology which...

10.1016/j.entcs.2015.10.024 article EN Electronic Notes in Theoretical Computer Science 2015-11-01

Load balancing plays a crucial role in many large scale systems. Several different load principles have been proposed the literature, such as Join-Shortest-Queue (JSQ) and its variations, or Join-Below-Threshold. We provide high level mathematical framework to examine heterogeneous server clusters mean-field limit system number of servers proportionally. aim identify both transient stationary for various choices principles, compute relevant performance measures distribution mean time jobs,...

10.2139/ssrn.4511962 preprint EN 2023-01-01

Abstract The steepest increase property of phase-type (PH) distributions was first proposed in O’Cinneide (1999) and proved Yao (2002), but since then has received little attention the research community. In this work we demonstrate that can be applied for proving previously unknown moment bounds PH with infinite or finite support. Of special interest are free specific representations except size representation. For support, it is shown such a distribution stochastically smaller than equal...

10.1017/apr.2019.7 article EN Advances in Applied Probability 2019-03-01

Load balancing plays a crucial role in many large scale computer systems. Much prior work has focused on systems with First-Come-First-Served (FCFS) servers. However, servers practical are more complicated. They serve multiple jobs at once, and their service rate can depend the number of service. Motivated by this, we study load for using Limited-Processor-Sharing (LPS). Our model heterogeneous servers, meaning curve multiprogramming level (limit sharing processor) differs between We focus...

10.1145/3393691.3394199 article EN 2020-06-08

We provide error bounds for the N-intertwined mean-field approximation (NIMFA) local density-dependent Markov population processes with a well-distributed underlying network structure showing NIMFA being accurate when typical vertex has many neighbors. The result justifies some of most common approximations used in epidemiology, statistical physics and opinion dynamics literature under certain conditions. allow interactions between more than 2 individuals, an hypergraph accordingly.

10.1016/j.physa.2022.128370 article EN cc-by-nc-nd Physica A Statistical Mechanics and its Applications 2022-12-01

The self-repelling Brownian polymer model (SRBP) initiated by Durrett and Rogers in [Durrett-Rogers (1992)] is the continuous space-time counterpart of myopic (or 'true') self-avoiding walk (MSAW) introduced physics literature Amit, Parisi Peliti [Amit-Parisi-Peliti (1983)]. In both cases, a random motion space pushed towards domains less visited past kind negative gradient occupation time measure. We investigate asymptotic behaviour SRBP non-recurrent dimensions. First, extending...

10.48550/arxiv.0912.5174 preprint EN other-oa arXiv (Cornell University) 2009-01-01

Highly concentrated functions play an important role in many research fields including control system analysis and physics, they turned out to be the key idea behind inverse Laplace transform methods as well. This paper uses matrix-exponential family of create highly functions, whose squared coefficient variation (SCV) is very low. In field stochastic modeling, have been used for decades. They advantages: are easy manipulate, always non-negative, integrals involving often closed-form...

10.48550/arxiv.1901.08627 preprint EN other-oa arXiv (Cornell University) 2019-01-01
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