# Miklós KrészUniversity of Szeged · Department of Applied Informatics

Miklós Krész

PhD

## About

62

Publications

12,988

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365

Citations

Citations since 2016

## Publications

Publications (62)

Brands can be defined as psychological constructs residing in our minds. By analyzing brand associations, we can study the mental constructs around them. In this paper, we study brands as parts of an associative network based on a word association database. We explore the communities–closely-knit groups in the mind–around brand names in this struct...

Mass timber construction systems, incorporating engineered wood products as structural elements, are gaining acceptance as a sustainable alternative to multi-story concrete or steel-frame structures. The relative novelty of these systems brings uncertainties on whether these buildings perform long-term as expected. Consequently, several structural...

In this paper, we provide a simple forward-looking approach to compare rating methods with respect to their stability over time. Given a rating vector of entities involved in the comparison and a ranking indicated by the rating, the stability of the methods is measured by the change in rating vector and ranks of the entities over time from a forwar...

Indoor Air Quality monitoring is a major asset to improving quality of life and building management. Today, the evolution of embedded technologies allows the implementation of such monitoring on the edge of the network. However, several concerns need to be addressed related to data security and privacy, routing and sink placement optimization, prot...

As environmental awareness is becoming increasingly important, alternatives are needed for the traditional forward product flows of supply chains. The field of reverse logistics covers activities that aim to recover resources from their final destination, and acts as the foundation of the efficient backward flow of these materials. Designing the ap...

Both community detection and influence maximization are well-researched fields of network science. Here, we investigate how several popular community detection algorithms can be used as part of a heuristic approach to influence maximization. The heuristic is based on the community value, a node-based metric defined on the outputs of overlapping com...

The mental lexicon stores words and information about words. The lexicon is seen by many researchers as a network, where lexical units are nodes and the different links between the units are connections. Based on the analysis of a word association network, in this article we show that different kinds of associative connections exist in the mental l...

Because of the wide variety of possible application fields and the spread of smart devices, the research of wireless sensor networks has become an increasingly important area in the last decade. During the design of these networks, several important aspects have to be considered, for example the lifetime of the network, expected battery usage, or r...

Recycling waste materials has become increasingly important recently both for economic and environmental reasons. In order to efficiently operate the backward flow of the materials, a basic challenge is to design the proper reverse logistics network containing the collection points, test centers and manufacturing plants. This paper studies the supp...

In the last years personnel cost became a huge factor in the financial management of many companies and institutions.The firms are obligated to employ their workers in accordance with the law prescribing labour rules. The companies can save costs with minimizing the differences between the real and the expected worktimes. Crew rostering is assignin...

A new methodology in temporal networks is presented for the use of fraud detection systems in the banking sector. Standard approaches of fraudulence monitoring mainly have the focus on the individual client data. Our approach will concentrate on the hidden data produced by the network of the transaction database. The methodology is based on a cycle...

As more and more cities adopt the use of smart cards as means to access public transportation networks, it becomes much easier to discover the mobility patterns of individual passengers. A natural way to represent such patters is in the form of graphs. In this paper we analyze the public transportation network of a major metropolitan area from a un...

Here we prove that counting maximum matchings in planar, bipartite graphs is #P-complete. This is somewhat surprising in the light that the number of perfect matchings in planar graphs can be computed in polynomial time. We also prove that counting non-necessarily perfect matchings in planar graphs is already #P-complete if the problem is restricte...

A confluent and terminating reduction system is introduced for graphs, which preserves the number of their perfect matchings. A union-find algorithm is presented to carry out reduction in almost linear time. The König property is investigated in the context of reduction by introducing the König deficiency of a graph G as the difference between the...

We present a new model for probabilistic forecasting using graph-based rating method. We provide a "forward-looking" type graph-based approach and apply it to predict football game outcomes by simply using the historical game results data of the investigated competition. The assumption of our model is that the rating of the teams after a game day c...

Abstract—Community detection is a widely discussed topicin network science which allows us to discover detailed in-formation about the connections between members of a givengroup. Communities play a critical role in the spreading ofviruses or the diffusion of information. In [1], [8] Kempe et al.proposed the Independent Cascade Model, defining a si...

This article introduces the schedule assignment problem for public transit, which aims to assign vehicle blocks of a planning period to buses in the fleet of a transportation company. This assignment has to satisfy several constraints, the most important of which is compatibility, meaning that certain blocks can only be serviced by buses belonging...

Papers dealing with optimization problems in public transportation usually follow the same methodology. The problem is modeled in a classical mathematical way, and then either solved directly using mathematical programming methods, or by the application of combinatorial heuristics. Even if this process yields an optimal solution, it might prove com...

The vehicle scheduling problem has been extensively studied in the past decades. Yet, most models and methods given in the literature consider only a theoretical scenario where vehicles just have to service the timetabled trips of the input. However, schedules created this way cannot be used in real life, as they should also consider constraints su...

The pre-planned schedules of a transportation company are often disrupted by unforeseen events. As a result of a disruption, a new schedule has to be produced as soon as possible. This process is called the vehicle rescheduling problem, which aims to solve a single disruption and restore the order of transportation. However, there are multiple disr...

Background: Obesity is a global epidemic associated with aging-like cellular processes. Resistance to hormones such as leptin and insulin are hallmarks in obesity. Contributing factors in obesity and overweight, including: lifestyle habits, hypothyroidism and genetics, can cause changes in the levels of metabolic parameters. Exercising is known to...

Several methods have been proposed recently to estimate the edge infection probabilities in infection or diffusion models. In this paper we will use the framework of the Generalized Cascade Model to define the Inverse Infection Problem—the problem of calculating these probabilities. We are going to show that the problem can be reduced to an optimiz...

In this paper we present preliminary results for a fast parallel adaptation of the well-known k-means clustering algorithm to graphs. We are going to use our method to detect communities in complex networks. For testing purposes we will use the graph generator of Lancichinetti et al., and we are going to compare our method with the OSLOM, CPM, and...

In this paper we propose a clique-based high-resolution overlapping community detection algorithm. The hub percolation method is able to find a large number of highly overlapping communities. Using different hub-selection strategies and parametrization we are able to fine tune the resolution of the algorithm. We also propose a weighted hub-selectio...

The Domingos-Richardson model, along with several other infection models, has a wide range of applications in prediction. In most of these, a fundamental problem arises: the edge infection probabilities are not known. To provide a systematic method for the estimation of these probabilities, the authors have published the Generalized Cascade Model a...

The applications of infection models like the Linear Threshold or the Domingos-Richardson model requires a graph weighted with infection probabilities. In many real-life appli-cations these probabilities are unknown; therefore a systematic method for the estimation of these probabilities is required. One of the methods proposed to solve this proble...

The daily schedule of a transportation company is often disrupted
by unforseen events. As a result, a new schedule has to be produced as soon as
possible to restore the order. In this paper, we consider the bus rescheduling
problem for solving such a scenario. We present a mathematical model for
the problem, and also introduce fast solution methods...

The driver scheduling problem in public transportation is defined in the following way. There is a set of operational tasks, and the goal is to define the sequence of these tasks as shifts in such a way that every task must be assigned to a shift without overlapping. In real-world situations several additional constraints need to be considered, whi...

The study of infection processes is an important field of science both from the theoretical and the practical point of view, and has many applications. In this paper we focus on the popular Independent Cascade model and its generalization. Unfortunately the exact computation of infection probabilities is a #P-complete problem [Chen2010], so one can...

In this article, we present heuristic methods for the vehicle scheduling problem that solve it by reducing the problem size using different variable fixing approaches. These methods are constructed in a way that takes some basic driver requirements into consideration as well. We show the efficiency of the methods on real-life and random data instan...

Overlapping community detection has already become an interesting prob-lem in data mining and also a useful technique in applications. This underlines the importance of following the lifetime of communities in real graphs. Palla et al. developed a promising method, and analyzed community evolution on two large databases [23]. We have followed their...

In this paper we propose a method for estimating the edge infection
probabilities in a generalized Domingos-Richardson model. The probabilities are
considered as unknown functions of a priori known edge attributes. To handle this
inverse infection problem, we divide the past data to learning and test sets. Then
we try to assign edge probabilities s...

In this paper we work out an application-oriented flexible optimization framework for driver scheduling. The new framework is general enough for the known optimization methods to be integrated and also take into consideration most of the practical requirements occurred in real-life public transportation systems. The potential usability of our appro...

In the area of optimization of public transportation there are several methods for modeling and solving vehicle and driver scheduling problems. We designed a sequential heuristic method for solving the combined (vehicle and driver scheduling) problem. Our model is based on a modification of the vehicle schedules to satisfy driver requirements. We i...

The study of various network related processes has recently become a key issue in many science disciplines including biology, chemistry , and physics, but also in sociology and other areas dealing with intensive communication. Different models are sought to describe such processes, among which automata appear to be successful candidates. Percolatio...

The study of various network related processes has recently become a key issue in many science disciplines including biology, chemistry, and physics, but also in sociology and other areas dealing with intensive communication. Different models are sought to describe such processes, among which automata appear to be successful candidates. Percolation...

A redex in a graph G is a triple r=(u,c,v) of distinct vertices that determine a 2-star. Shrinking r means deleting the center c and merging u with v intoone vertex. Reduction of G entails shrinking all of its redexes in a recursive way, and, at the same time, deleting all loops that are created during this process. It is shown that reduction can b...

This paper describes the most obvious way for public transportation companies to decrease their operational cost. This is
to optimize the logistics of their operations. The optimization process is a very complex operation and therefore we split
the logistics into three phases: vehicle scheduling, driver scheduling and driverrostering. The phases re...

Soliton automata are a mathematical model for electronic switching at the molecular level. In the design of soliton circuits, deterministic automata are of primary importance. The underlying graphs of such automata, called soliton grahs, are characterized in terms of generalized trees and graphs having a unique perfect matching. Based on this chara...

Soliton automata are the mathematical models of certain possible molecular switching devices. Both from theoretical and practical point of view, it is a central question to describe soliton automata with constant external edges. Extending a result of Dassow and Jürgensen, we characterize soliton automata in this special case.

A counterpart of Tutte's Theorem and Berge's formula is proved for open graphs with perfect (maximum) internal matchings. Properties of barriers and factor-critical graphs are studied in the new context, and an efficient algorithm is given to find maximal barriers of graphs having a perfect internal matching.

An efficient method based on the elementary decomposition of soliton graphs is worked out for soliton automata by which their descriptional complexity is reduced to automata defined by elementary graphs.

Soliton automata are the mathematical models of certain possible molecular switching devices called soliton circuits. Both from theoretical and practical point of view, it is a central question to describe soliton automata with a single external vertex. Extending a result of Dassow and Jurgensen, we characterize nondeterministic automata in this sp...

Soliton graphs are studied in the context of a reduction procedure that simplifies the structure of graphs without affecting the deterministic property of the corresponding automata. It is shown that an elementary soliton graph defines a deterministic automaton iff it reduces to a graph not containing even-length cycles. Based on this result, a gen...

A matching M is called flexible if there exists an alternating cycle with respect to M. Given a graph G=(V,E) and S ⊆ V, a flexible matching M ⊆ E is sought which covers a maximum number of vertices belonging to S. It is proved that the existence of such a matching is decidable in O(|V|·|E|)\mathcal{O}(|V|\cdot |E|) time, and a concrete flexible ma...

Soliton automata are a mathematical model for electronic switching at the molecular level. In the design of soliton circuits, deterministic automata are of primary importance. The underlying graphs of such automata, called soliton grahs, are characterized in terms of generalized trees and graphs having a unique perfect matching. Based on this chara...

Soliton circuits are among the most promising alternatives for molecular electronic devices based on the design of molecular
level conventional digital circuits. In order to capture the logical and computational aspects of these circuits, a mathematical
model called soliton automaton was introduced by Dassow and Jürgensen in 1990.

An efficient method based on the elementary decomposition of soliton graphs is worked out for soliton automata by which their descriptional complexity is reduced to automata defined by elementary graphs.

Splitters are introduced to capture the meaning of barriers in graphs having a perfect internal matching. The factor-critical property is extended in a natural way to accommodate such graphs, and a characterization of factor-critical graphs is given in the new context. Two Tutte type theorems are presented for open graphs with perfect internal matc...

Graphs with perfect internal matchings are decomposed into elementary components, and these components are given a structure reflecting the order in which they can be reached by external alternating paths. It is shown that the set of elementary components can be grouped into pairwise disjoint families determined by the “two-way accessible” relation...

The order of elementary components in an open graph G having a perfect internal matching is studied along external alternating paths covering these components. For two elementary components C and D, D is a predecessor of C if all external alternating paths leading to C must cover D on their way. The immediate predecessor of C is an elementary compo...

Soliton automata are the mathematical models of certain possible molecular switching devices. In this paper we work out a decomposition of soliton automata through the structure of their underlying graphs. These results lead to the original aim, to give a characterization of soliton automata in general case.

Questions raised by DNA-chip technology pose new challenges for bioinformatics. In contrast to the information stored in static DNA databases, DNA-chip experiments provide a large amount of information about dynamic changes in the expression of several thousand genes simultaneously. It is a natural goal to exploit both of these information sources,...

## Projects

Project (1)

Standardized metabolic panel data of numerous blood tests are exposed to various network-analysis methods in order to deductively find "2 steps" effects. With the ethical approval of the Hungarian Health Ministry on anonymous, retrospectively collected data. Can be considered as a big health data project.