Communications - Scientific Letters of the University of Zilina, 2016 (vol. 18), issue 1A
Articles
Usability of the SIP Protocol Within Smart Home Solutions
Jakub Hrabovsky, Pavel Segec, Peter Paluch, Marek Moravcik, Jozef Papan
Communications - Scientific Letters of the University of Zilina 2016, 18(11):4-12 | DOI: 10.26552/com.C.2016.1A.4-12 
A smart home is being an important part of research due to its impact on the life of many people, who decide to try this partially known concept of building and controlling their houses. In this paper we present a little different approach to the implementation of a smart home structure and its methods in real environment. As a part of the work we specify main requirements on the architectural design, which should be considered in final solution. Our research is focused primarily on the use of open standards and tools. This approach became popular because it provides an alternative view in comparison to commercial ones, where mostly proprietary and...
Object-In-Fluid Framework in Modeling of Blood Flow in Microfluidic Channels
Ivan Cimrak, Katarina Bachrata, Hynek Bachraty, Iveta Jancigova, Renata Tothova, Martin Busik, Martin Slavik, Markus Gusenbauer
Communications - Scientific Letters of the University of Zilina 2016, 18(11):13-20 | DOI: 10.26552/com.C.2016.1A.13-20
We present a fully three-dimensional computational model of red blood cells and their flow in a fluid. This model includes all components necessary to capture important physical and biological aspects of the cell flow. It comprises descriptions of elasticity of the cell membrane, cell-cell interactions, two-way cell-fluid interaction, and adhesion of cell to surfaces. Using this model, we analyze different processes involving flow of cells. We present the results of ongoing research concerning the development of model for cell adhesion, the analysis of microfluidic devices with periodic obstacle arrays, the optimization of microfluidic connectors and...
The Column Generatiion and Traiin Crew Scheduliing
Jaroslav Janacek, Peter Marton, Matyas Koniorczyk
Communications - Scientific Letters of the University of Zilina 2016, 18(11):21-27 | DOI: 10.26552/com.C.2016.1A.21-27
Better productivity and efficiency is more and more required in the railway operation. The train crew management is one of the several problems that could be solved using mathematical methods. Crew management is a problem that is well-known in Operations Research. We compare two approaches for solving the train crew scheduling problem. The first approach consists of solving the original problem by single model. The second approach corresponds to the step-by-step column generation. This technique was originally based on Dantzig-Wolfe decomposition. The benchmarks used for comparison of both approaches originate in real problems from railway systems...
Searching Correlations Between Communication and Motivation
Martina Blaskova, Rudolf Blasko, Stanislaw Borkowski, Joanna Rosak-Szyrocka
Communications - Scientific Letters of the University of Zilina 2016, 18(11):28-35 | DOI: 10.26552/com.C.2016.1A.28-35
The aim of the paper is to examine various contents of the relations between communications (including informativeness), and motivation, i.e. consider the benefits of effective communication as well the risks of ineffective communication acting on motivation, perceive feedback as sustainable and accelerative element of any communication system, reflect on communication and informativeness as motivational tools, consider the need to motivate employees for quality communication and raising awareness in the organization and so on. The empirical part presents the most significant results of Slovak-Polish research in motivation regarding the linkages of...
Sports Sponsoriing - Part of Corporate Strategy
Michal Varmus, Viliam Lendel, Jakub Soviar, Josef Vodak, Milan Kubina
Communications - Scientific Letters of the University of Zilina 2016, 18(11):36-41 | DOI: 10.26552/com.C.2016.1A.36-41
Sponsoring is closely connected with sports and is often incorrectly seen as mere paid advertising. In this article we focused on sponsoring and how it is understood and perceived by Slovak marketing managers and the business community. Based on a survey, interviews and literature analysis we highlighted the strategic aspect of sponsoring in relation to the companies and sports clubs. We focused only on the main factors related to sponsoring. This article also represents a basis for further research in order to better define approaches and motivational aspects of sponsoring.
Identification of the Main Aspects of Innovation Management and the Problems Arising from their Misunderstanding
Viliam Lendel, Stefan Hittmar, Wlodzimierz Sroka, Eva Siantova
Communications - Scientific Letters of the University of Zilina 2016, 18(11):42-48 | DOI: 10.26552/com.C.2016.1A.42-48
Goal of the article is to identify main aspects of innovation management using detailed analysis of available scientific literature together with outcomes of performed empirical research. With the identified main aspects, we were able to identify problematic areas related to the use of innovation management and to propose a number of recommendations in order to correct these issues. The article thus brings to managers a handy tool in a form of a set of recommendations (instructions) that are meant to support problem-free use of innovation management within a company.
Approaches to the Quantification of the Human Capital Efficiency in Enterprises
Alzbeta Kucharcikova, Lubica Konusikova, Emese Tokarcikova
Communications - Scientific Letters of the University of Zilina 2016, 18(11):49-54 | DOI: 10.26552/com.C.2016.1A.49-54
Human capital is one of the enterprise inputs. There are people who are the bearers of new knowledge, ideas, experiences and skills; they contribute to their own personal growth as well as to increasing the performance and competitiveness of the whole enterprise. Human capital management helps enterprises to achieve enterprise goals just by using the human capital efficiently. For the assessment of the results achieved and directing further development it is important to know how to measure the efficiency. The aim of the article is: based on the study of special and scientific foreign literature to identify and compare the different theoretical approaches...
Uniform Workload Distribution Problems
Peter Czimmermann, Stefan Pesko, Jan Cerny
Communications - Scientific Letters of the University of Zilina 2016, 18(11):55-58 | DOI: 10.26552/com.C.2016.1A.55-58
In this paper we review common studies from the years 1984-2015 of problems occurring in uniform scheduling of workload distributions. These problems were formulated first by Pesko in dealing with the practical problem of regular scheduling of service vehicles. Given the nonnegative, real matrix with daily records of vehicles as columns, we need to minimize some irregularity measure of row sums (workloads) by permuting matrix columns. The problem has various practical modifications, such as the weighted rows of matrix, workload uncertainty variance, graph approach of exchange of elements and generalized inverse formulations. Some of them are presented...
Simulation of Parameters Influencing the Electric Vehicle Range
Lubos Kucera, Igor Gajdac, Martin Mruzek
Communications - Scientific Letters of the University of Zilina 2016, 18(11):59-63 | DOI: 10.26552/com.C.2016.1A.59-63
Increasing the range of electric vehicles is crucial for electromobility expansion. Using the simulation it is possible to identify the parameters that have a significant impact on the electric vehicle range. Therefore, the analysis of parameters influencing the range was created. Simulation was based on real driving cycles for better accuracy.
Implementation of Memetic Algorithms into Structural Optimization
Peter Pechac, Milan Saga, Ardeshir Guran, Leszek Radziszewski
Communications - Scientific Letters of the University of Zilina 2016, 18(11):64-69 | DOI: 10.26552/com.C.2016.1A.64-69
The paper presents an implementation of the memetic algorithm for discrete structural optimization. This algorithm is a combination of genetic algorithm and five local search methods. The proposed memetic algorithm is able to choose the right local search method based on performance which is evaluated in real time during optimization.
Numerical Simulation of Melt Filtration Process
Marek Bruna, Dana Bolibruchova, Petr Prochazka
Communications - Scientific Letters of the University of Zilina 2016, 18(11):70-74 | DOI: 10.26552/com.C.2016.1A.70-74
The paper aims to comprehensively elaborate the impact of ceramic filter design on filling parameters during the casting of aluminium alloys. Experimental work focuses mainly on the evaluation of velocity, filling time and turbulences in the close vicinity of the filter by numerical simulation. The whole experiment was divided into two stages: in the first stage was evaluated set of three filters with different channels cross-section geometry, and in the second stage was evaluated set composed of four filters with different number of channels and channels diameter.
Numerical Simulation of Residual Stresses and Distortions of T-Joint Welding for Bridge Construction Application
Radoslav Konar, Marek Patek, Michal Sventek
Communications - Scientific Letters of the University of Zilina 2016, 18(11):75-80 | DOI: 10.26552/com.C.2016.1A.75-80
Prediction of the distortions and residual stresses of the welded steel structures is still very important to reduction of the costs, mainly during the optimization of welding process. If there is necessity of the higher welding current to ensure weld penetration, distortions might be influenced by appropriate welding sequence. During optimization process, numerical analysis of welding process, based on finite element method, can be used to prediction of distortions at different welding sequences without necessity of preparing high amount of experimental samples. Numerical simulation of T-joint welding process is presented in this article, together...
New Possibilities of Robot Arm Motion Simulation
Alexander Rengevic, Darina Kumicakova
Communications - Scientific Letters of the University of Zilina 2016, 18(11):81-86 | DOI: 10.26552/com.C.2016.1A.81-86
The importance of computer simulations of the industrial robot arm motions at the technological scene becomes more important especially in connection with industrial applications of the new types of robot arm kinematic structures or with solving the human robot safety collaboration in industry. The article is aimed at the simulation of the basic (primitive) tasks executed by industrial robot with utilization of software packages of the "open-source" platform ROS. ROS is the software of modular architecture that extends the capabilities of the different robot types programming and controlling.
Logistics Processes and Systems Design Using Computer Simulation
Martin Krajcovic, Andrej Stefanik, Luboslav Dulina
Communications - Scientific Letters of the University of Zilina 2016, 18(11):87-94 | DOI: 10.26552/com.C.2016.1A.87-94
In the course of logistics systems designing, great emphasis has been recently put on speed, quality and flexibility of the proposed solutions. The logistics system draft requires then not only an analysis of the logistics systems requirements, a draft of several solution variants and their static verification but also dynamic verification of performance of the designed system in real conditions in a form of computer simulation. The following article deals with the issues of the use of computer simulation for logistics processes and systems designing.
Simulation of Residual Stresses in Surface and Subsurface Layer after Machining
Andrej Czan, Michal Sajgalik, Jozef Holubjak, Marianna Piesova, Tatiana Czanova
Communications - Scientific Letters of the University of Zilina 2016, 18(11):95-100 | DOI: 10.26552/com.C.2016.1A.95-100
This article deals with non-destructive detection method of residual stress as analytical tool of expected distribution of residual stress in surface and sub-surface layers. Based on measurements, which can consists of cloud of points, lines or surface map of residual stress, we can simulate potential distribution of residual stress in surface and subsurface layers via mathematical-statistical procedures. Right identification of residual stress and its distribution can improve the prediction of failures and similar damage incidences due to workload over lifetime of components and also, it can be used as evaluation parameter of suitability of applied...
Use of MSC.Adams Software Product in Modelling Vibration Sources
Alzbeta Sapietova, Vladimir Dekys
Communications - Scientific Letters of the University of Zilina 2016, 18(11):101-107 | DOI: 10.26552/com.C.2016.1A.101-107
This paper presents the methodology of rotating device modelling in order to facilitate correct evaluation of selected, usually malfunction (degraded) states of rotating machines of mechanical systems, especially of gearboxes. The analysis was performed using mathematical models utilising MSC.ADAMS software product to solve the dynamics of a system of bodies. The correctness of the proposed method is verified by qualitative comparison of simulation results with the presented symptoms of malfunction states and also by comparison with real measurement results from technical practice.
Determination of the Optimum Preload of Roller Bearings in Terms of their Life Using Fem
Slavomir Hrcek, Robert Kohar, Stefan Medvecky, Branislav Krchnavy, Marcel Caco
Communications - Scientific Letters of the University of Zilina 2016, 18(11):108-114 | DOI: 10.26552/com.C.2016.1A.108-114
The objective of this paper is to describe the procedure of correct determination of the optimum preload of tapered roller bearings in terms of their fatigue life, using the procedure laid down in ISO 281, and by analysis of contact stress state (analytically and by the FEM) with application of the Lundberg-Palmgren theory. The procedures will be applied to a specific example of the fit of the output shaft of a gearbox in a pair of tapered roller bearings designed specifically for this application.
Numerical Simulation of Heat Transport from the Electric Arc Furnace to the Heat Recovery System
Milan Malcho, Jozef Jandacka, Richard Lenhard, Stanislav Gavlas, Tadeas Ochodek
Communications - Scientific Letters of the University of Zilina 2016, 18(11):115-121 | DOI: 10.26552/com.C.2016.1A.115-121
The paper presents a numerical model of heat transport from melting charge of the electric arc furnace designed for ferroalloy production, into a cooled roof of the electric arc furnace from which waste heat is led to the heating system of a company. The model considers the influence of an asymmetric flue gas removal and geometry of electrode arrangement. The model was developed implementing CFD - the finite volume method in ANSYS - Fluent program code. Outputs of the simulation model served as a basis for dimensioning heat exchanger circuits designed for waste heat recovery to provide a company heating.