Communications - Scientific Letters of the University of Zilina, 2015 (vol. 17), issue 2
Articles
Re-Aggregation Heuristics for the Large Location Problems with Lexicographic Minimax Objective
Matej Cebecauer, Lubos Buzna
Communications - Scientific Letters of the University of Zilina 2015, 17(2):4-10 | DOI: 10.26552/com.C.2015.2.4-10 
We propose a new heuristic algorithm that provides solutions to the discrete lexicographic minimax location problem. The algorithm is applicable to large instances of the problem. The lexicographic minimax location problem is known to be NP-hard. Therefore, the large instances of the problem are not computable in reasonable time. An aggregation is a valuable tool that allows to adjust the size of the problem and approximate the problem by another one that can be solved. An inevitable consequence of aggregation is the loss of the precision. Typically, an aggregation method is used only once, in the initial phase of the solving process. Here, we propose...
Insertion Method for Multiple Messenger Problem with Multiple Depots
Jan Fabry
Communications - Scientific Letters of the University of Zilina 2015, 17(2):11-14 | DOI: 10.26552/com.C.2015.2.11-14
Messenger problem, as the variation of pickup and delivery problem, deals with the transport of a set of packages from their origins to given destinations. In reality, several vehicles have to be used to be able to satisfy all requirements within given time limit. Messengers can be located in one or multiple depots. Because of NP-hardness of the problem it is impossible, for most real problems, to find the optimal solution in acceptable time. Therefore, heuristic algorithms must be used. In the paper, insertion method for routes generation is presented. As the computational experiments in VBA for Excel show, obtained results can be improved using the...
Min-Max Optimization of Emergency Service System by Exposing Constraints
Jaroslav Janacek, Marek Kvet
Communications - Scientific Letters of the University of Zilina 2015, 17(2):15-22 | DOI: 10.26552/com.C.2015.2.15-22
This paper deals with the fair public service system design using the weighted p-median problem formulation. Studied generalized system disutility follows the idea that the individual user's disutility comes from more than one located service center and the contributions from relevant centers are weighted by some coefficients. To achieve fairness in such systems, various schemes may be applied. The strongest criterion consists in the process when the disutility of the worst situated users is minimized first, and then the disutility of better located users is optimized under the condition that the disutility of the worst situated users does not worsen....
Preconditioning in the Backtracking Duty Generation of Passenger Rail Crew Scheduling: A Case Study
Matyas Koniorczyk, Borbala Talas, Ferenc Gedeon
Communications - Scientific Letters of the University of Zilina 2015, 17(2):23-29 | DOI: 10.26552/com.C.2015.2.23-29
We describe briefly the crew scheduling and rostering approach implemented in Railm@n, the system used by MAV START, the passenger railway transport company of Hungary, to organize the work of passenger train crews that is, conductors. Then we discuss the scheduling (duty generation) phase of the algorithm in detail. When treated in full generality, the problem already scales to an untractable size. We describe our successful experience with the use of preconditioning to keep the problem tractable. The approach may be useful in timetable planning and depot planning, too.
Modelling Passengers' Arrivals at Public Transport Stops
Ludmila Janosikova, Martin Slavik
Communications - Scientific Letters of the University of Zilina 2015, 17(2):30-34 | DOI: 10.26552/com.C.2015.2.30-34
The paper presents statistical exploration of passengers' arrivals at bus stops in urban public transport. First, it describes the methodology which is applied on the urban public transport system where the following conditions are met: (i) passengers are familiar with the timetables, (ii) the vehicles run on time, and (iii) the capacity of the vehicles is sufficient. The methodology is demonstrated on the urban public transport in Zilina, Slovak Republic. The correlation analysis reveals that there is a correlation between the waiting time and headway. The relationship between these variables can be described by a linear function or better by a logarithmic...
An Experimental Study on Dependence of Time Intervals for Connections on Optimization Computations for Task of Aircraft Scheduling
Vojtech Graf, Dusan Teichmann, Michal Dorda
Communications - Scientific Letters of the University of Zilina 2015, 17(2):35-41 | DOI: 10.26552/com.C.2015.2.35-41
Mathematical models are often employed for optimization of different problems arising in transport. It is a well-known fact that calculation times, which are necessary to find out an optimal solution, usually increase together with increasing scale of mathematical models (scale is defined by the number of variables and constraints that form each mathematical model). For some types of linear models (usually for the models in which logical or integer variables are used) it often happens that if scale of the model exceeds a certain limit, the model can be solved exactly either with big difficulties or cannot be solved at all. It is also known that the...
Design of Capacitated Emergency Service System
Lydia Gabrisova, Jaroslav Janacek
Communications - Scientific Letters of the University of Zilina 2015, 17(2):42-48 | DOI: 10.26552/com.C.2015.2.42-48
Optimal design of the emergency service systems mostly consists in the decisions on a deployment of service centers, which provide the nearest system users with the associated service. As the demand for emergency service occurs randomly, the nearest service center may be occupied by servicing some previous demand and thus the current demand must be serviced from some more distant available service center. This phenomenon is dealt with in this paper where the center capacity is considered in the service system design to mitigate frequency of the above-mentioned events. For this purpose, two approaches to the capacitated service center deployment were...
A Site Selection Model for Wayside Train Monitoring Systems at Serbian Railways
Sanjin Milinkovic, Slavko Veskovic, Biljana Mitrovic, Zivota Dordevic, Peter Marton
Communications - Scientific Letters of the University of Zilina 2015, 17(2):49-54 | DOI: 10.26552/com.C.2015.2.49-54
To remain competitive in a transport market, railway needs to increase reliability and to reduce the transport costs. Timely detection of a fault or defect can prevent a possible accident and can reduce maintenance costs. This paper presents a model for selection of locations for wayside train monitoring systems that are used to detect faults on the wagons. We present two models: first, based on multi-criteria decision making method is used for selecting a macro location, and second model based on fuzzy logic is used to determine a micro location of a wayside train monitoring system work station on Serbian rail network.
Two Efficient Algorithms for Weighted P-Median Problem
Vladimir Medvid
Communications - Scientific Letters of the University of Zilina 2015, 17(2):55-59 | DOI: 10.26552/com.C.2015.2.55-59
We propose a genetic algorithm for a weighted p-median problem. It is a facility location problem. The algorithm generates a good solution quickly. Computational tests were realized on five different tasks from 21 vertices to 100 vertices and from p-median from p=3 to p=6. The tests were performed 100 times on every task. There were created some modifications of these tasks for a proposed genetic algorithm. The best solution generated by this algorithm is within 0.6% of the optimum for 80% of the tasks. The other 20% of the tasks is within 1.6% of the optimum. Time of realization is within 5.9 s.
Assessment of Railway Station Modernisation Combining Risk Analysis with Multi-Criteria Analysis
Tomas Javorik, Lukas Tyfa
Communications - Scientific Letters of the University of Zilina 2015, 17(2):60-65 | DOI: 10.26552/com.C.2015.2.60-65
When modernising train stations, several options are usually available for the layout of the tracks and its parameters. The best option is chosen by assessing different criteria; it is not an exact procedure, but a compromise between often different perspectives. Many methods are available to aid the decision-making process in these situations; the authors of this article apply mutually combined multi-criteria and qualitative risk analysis to assess two self-proposed options for the modernisation of the Bakov nad Jizerou station (situated in Central Bohemia in the Czech Republic).
Tax Evasion in Sales Cuts Registered by Electronic Cash Register
Maria Durisova, Beata Holkova, Michal Lekyr
Communications - Scientific Letters of the University of Zilina 2015, 17(2):66-72 | DOI: 10.26552/com.C.2015.2.66-72
Tax evasion is a persistent problem of public finances. Sales cuts registered by electronic cash register (hereinafter referred to as "ECR") is part of tax evasion. The State, through constant changes in legislation, creates barriers against them, which are effective only in the short term. The paper is based on the documentation of administrative offences arising from demands and communications with the financial administration. It analyses the changes in the law relating to the elimination of tax evasion by recording sales of ECR and evaluates them. It applies a model approach for the identification of subjects and links in the system. Risky relationships...
Approaches to Active Labour Market Policy in The Slovak Republic, Czech Republic and in Finland
Lubica Konusikova, Alzbeta Kucharcikova
Communications - Scientific Letters of the University of Zilina 2015, 17(2):73-79 | DOI: 10.26552/com.C.2015.2.73-79
The subject matter of the article consists in the issue of unemployment, which is the problem in many countries. The article describes approaches to the solution of the unemployment from the point of view of several economic specializations in theory. Active labour-market policies have developed significantly over the past two decades across Organization for Economic Cooperation and Development (OECD). This article describes the approaches to the solution of unemployment problem of the Czech Republic, Slovak Republic and Finland. Objective of this article is to account variant of active labour market policy.
Communication Networks as Base for Mobility - Trend Development of Network Architectures
Reiner Keil, Dirk Krone, Iveta Kremenova, Radovan Madlenak
Communications - Scientific Letters of the University of Zilina 2015, 17(2):80-85 | DOI: 10.26552/com.C.2015.2.80-85
New network architectures are required for a flexible service provisioning. These are characterized by the transition from channel-switching to packet-switched networks. The amount of the collected information needs to be provided in these network architectures at the right time at the right place for processing in the control systems and end-systems. The warranty of parameters such as duration and availability within the network architectures is a requirement for the function of the service to be provided. The requirements must be specified for an application to a suitability of the architecture in terms of safety with the required parameters for...
The Methodology of the Biomechanical Movements for the Disabled Based on Art Therapy
Ivana Zidek, Jana Musinska, Jozef Zivcak
Communications - Scientific Letters of the University of Zilina 2015, 17(2):86-91 | DOI: 10.26552/com.C.2015.2.86-91
The essence of the research work is to open up the new possibilities in the treatment processes within rehabilitation, physiotherapy and consequent movement re-education process for people with disabilities, post-traumatic conditions, or degenerative disease. Art therapy is a special type of psychotherapy that focuses on the development of creative skills, emotional development and interpersonal relationships of the mentally, physically or socially disturbed individuals. The methodology proposal includes the systems of rehabilitation, therapeutic physical education, physiotherapy, and ergotherapy. The purpose of the methodology of the biomechanical...
Impact of Road Infrastructure Pricing on Transport Planning
Milos Poliak, Stefania Semanova, Salvador Hernandez, Eliska Pastuszkova
Communications - Scientific Letters of the University of Zilina 2015, 17(2):92-97 | DOI: 10.26552/com.C.2015.2.92-97
The paper deals with an issue of the impact of road infrastructure pricing on transport planning. The first part describes the history of road infrastructure pricing in the USA and the EU. The paper also describes an applicable methodology of toll rate determination in the EU. Further part of the paper deals with the factors affecting decision-making of carriers while planning a route of transport. Especially, it deals with a value of time savings and savings in fuel costs while deciding among several routes of transport. The proposal of a methodology for toll rate determination, taking into account the value of time savings for a carrier while using...
Operational Reliability of Fire Appliances on Mercedes-Benz Chassis with Brigades of Fire Rescue Service of the Moravian-Silesian Region
Ladislav Janosik, Marek Cochlar, Pavel Polednak
Communications - Scientific Letters of the University of Zilina 2015, 17(2):98-102 | DOI: 10.26552/com.C.2015.2.98-102
This paper is focused on the evaluation of data obtained from operational records of fire appliances for the period 2010 - 2013 with emphasis on fire appliances built on Mercedes-Benz chassis. These vehicles are operated by the professional units of Fire Rescue Service of the Moravian-Silesian Region. The data recorded in electronic form in operational records were analysed. The primary result of this analysis was the selection of repairs after failure. Failure severity with regard to the functional reliability of fire appliances was used as selection criterion. Subsequently the assessment of the reliability was performed by setting selected characteristics...
Moral Implications of Augustine's Philosophical and Spiritual Journey in his Confessiones
Michal Valco, Roman Kralik, Lee Barrett
Communications - Scientific Letters of the University of Zilina 2015, 17(2):103-108 | DOI: 10.26552/com.C.2015.2.103-108
Aurelius Augustinus, though born to a Christian mother, had undergone a long and tedious spiritual journey in his search for truth and meaning. Youthful hedonism gave way to Skepticism, Manichaeism, and later on to Neo-Platonism as he searched for answers to some of the most pressing existential questions of mankind. Platonism, above all, proved to be (in its renewed, mystical form of Neo-Platonism) the most influential factor in his spiritual and intellectual journey. What we see in Augustine, in his personal struggle with philosophical ideas and religious cults that allowed him to become one of the most influential Christian philosopher of all times,...
Nanotechnology Safety as a New Challenge for Occupational Health and Safety
Pavel Danihelka, Martie Van Tongeren, Lucie Sikorova, Tana Brzicova
Communications - Scientific Letters of the University of Zilina 2015, 17(2):109-114 | DOI: 10.26552/com.C.2015.2.109-114
Nanotechnology as a key enabling technology offers great potential for economy and society, but may also bring new threats to workers´ health due to new aspects of hazard, ways of transport, nanoparticles transformation and accumulation. Even if principal paradigms of classical toxicology are probably applicable to nanostructured materials, important gaps still exist. One of the most important topics to be developed is the occupational exposure assessment with special attention paid to the exposure measurement and exposure scenarios building. This article brings insight into the state-of-the-art of the nanotechnology safety and analyses key needs in...