Communications - Scientific Letters of the University of Zilina, 2000 (vol. 2), issue 4
Articles
Unified View of Optimization of Transport Supply
Jan Cerny
Communications - Scientific Letters of the University of Zilina 2000, 2(4):4-8 | DOI: 10.26552/com.C.2000.4.4-8 
The paper presents so called transport supply optimization problem, which can be generally formulated as to find an optimum covering of demand. The types of supply can be very different (as goods-supply, transport-supply etc). In spite of variability of real supply optimization problems they have several common properties. For the presented problem it formulates continuous and discrete model, shows that both models have similar structure and presents solutions of corresponding mathematical problems.
Transport Accessibility of Villages
Ludmila Janosikova, Alexander Kubani
Communications - Scientific Letters of the University of Zilina 2000, 2(4):9-15 | DOI: 10.26552/com.C.2000.4.9-15
This paper deals with a method for quality analysis of mass transport in a region. Time accessibility of villages was chosen as a quality criterion. The region of ®ilina was examined. The combination of bus and train transport was taken into account. Accessibility was examined in dependence on three categories of passengers: irregular passengers, working people and students. The results were analysed using a geographic information system.
Cost-Effective Inventory Control Under Risk
Ondrej Bartl
Communications - Scientific Letters of the University of Zilina 2000, 2(4):16-28 | DOI: 10.26552/com.C.2000.4.16-28
Inventory systems play an important role in manufacturing and service providing organisations to support fluency of production or service. Evolution in time and environment of risk usually characterise operation of such systems. Proper control rules are required for decision making on replenishment orders. If stochastic dynamics of system motion exhibits the Markovian property, then Markov decision models can be employed to reveal a cost-effective inventory control policy. A single-item periodic-review inventory system in the maintenance centre of amanufacturing or transportation organisation with aPoisson arrival stream of demand requirements for...
The Pyramidal Method for Traveling Salesman Problem
Stefan Pesko
Communications - Scientific Letters of the University of Zilina 2000, 2(4):29-34 | DOI: 10.26552/com.C.2000.4.29-34
A shortest pyramidal tour (SPT) is a well-solved case of TSP when a distance matrix is the Monge matrix. We study heuristic repeating method for SPT with the distance matrix without restriction. A new procedure for computing SPT is based on a shortest path in the network. Good results for solved the Euclidean TSP instances with the stochastic version of the demonstrated method are presented.
Transport-Optimal Partitioning of a Region
Jaroslav Janacek
Communications - Scientific Letters of the University of Zilina 2000, 2(4):35-42 | DOI: 10.26552/com.C.2000.4.35-42
This paper deals with a problem of inhabited region partitioning. The partitioning is performed when a public administration system is changed. Location of subregion centres is usually connected with the partitioning. Both of these activities, the location subregions centres and forming of the subregions, have impacted public service accessibility. When the service provided to inhabitants is concentrated in the subregion centres, accessibility can be evaluated and the problem of optimal partitioning and centre location can be solved. This paper shows various partitioning problems and reports on associated solution techniques and results obtained for...
The Discrete Process of Storage with Two Priority Classes
Julius Rebo
Communications - Scientific Letters of the University of Zilina 2000, 2(4):43-51 | DOI: 10.26552/com.C.2000.4.43-51
This paper is devoted to a specific model of the discrete process of storage with two priority classes. Every priority class of the elements is formed by independent Poisson distributed incoming streams of the elements. There are derived some basic characteristic values, a method of assignment optimal out-going capacities for the classes of priority and a costs minimising method for the length of the storage period as well.
Application of the Minimalization of Maximal Error Method in Transformation by Polynomial Approximation
Robert Tenzer
Communications - Scientific Letters of the University of Zilina 2000, 2(4):52-58 | DOI: 10.26552/com.C.2000.4.52-58
The least square method is generally used for an estimation of the coefficients of polynomial transformation. The paper describes the rationalization of polynomial approximation by the minimization of maximal error model (Chebyshew approximation).
Mathematical Modelling of the Highway Influence to Air Pollution
Daniela Durcanska, Ferdinand Hesek
Communications - Scientific Letters of the University of Zilina 2000, 2(4):59-68 | DOI: 10.26552/com.C.2000.4.59-68
The paper deals with the procedure of the highway project evaluation from the standpoint of highway influence to the environment. The official calculation methodology of air pollution is used for that purpose. The methodology was adjusted so that the differences of highways from the common roads were taken into consideration by the calculation of pollutant distribution in the surroundings of the highway, mainly from the high speed of the traffic stream point of view.
Railroad Turnouts - From Surveying to Information System
Stanislav Hodas
Communications - Scientific Letters of the University of Zilina 2000, 2(4):69-73 | DOI: 10.26552/com.C.2000.4.69-73
Railroad turnouts and crossings are inseparable elements of railway infrastructure for providing the fluent train traffic which are as a rule, joined into certain trackage groups. The information registration of their position in the railway lay-out is necessary. In our case we will point out the design of the information system which could be employed in the railway engineering works during the maintenance of the above mentioned objects in operation. This information system was created for the independent railway society which owns the railway yard in its railway system.
Wind Engineering in the 21st Century
Vladimir Feranec
Communications - Scientific Letters of the University of Zilina 2000, 2(4):74-83 | DOI: 10.26552/com.C.2000.4.74-83
Progress in wind engineering during last 3-5 decades is described in this paper, from the existence of wind tunnels with the simulated atmospheric boundary layer and introducing random processes in wind load on buildings and structures. State of the art is presented from the First International Conference on Wind Effects on Buildings and Structures in U. K. (1963) together with some visions for the future. Some remarks are also devoted to wind engineering research in the Department of Structural Mechanics, Civil Engineering Faculty, University of ®ilina [1] - [31].
Problems and Methods of Control in Transportation Systems
Petr Cenek
Communications - Scientific Letters of the University of Zilina 2000, 2(4):84-90 | DOI: 10.26552/com.C.2000.4.84-90
The basic idea of the article is to show various problems of control and management in transportation systems and the necessity of an available information support. The importance of transportation and some ideas on its significance for a modern society is reflected in the paper. The model of a transportation system is further described together with some optimisation problems and methods how to solve them. The necessity of a generalisation of a data model and standardisation of data on the transportation infrastructure as well as statistical data on transportation flows is stressed as abasic need for any exact method of control in transportation systems.
It Contributions to Efficient Transport Management
Anthony Wren
Communications - Scientific Letters of the University of Zilina 2000, 2(4):91-94 | DOI: 10.26552/com.C.2000.4.91-94
Transport systems revolve around their schedules. Computer scheduling systems are now installed in very many transport organisations, and savings are well documented. These may be: direct savings from more efficient schedules; indirect savings because of the ability provided to investigate speedily alternative scenarios; induced savings where the computer has pointed out how adjustments to timetables or operating rules would increase efficiency. However, the use of an IT system for scheduling does not, in itself, guarantee a good schedule. There are many attractively presented systems that produce poor schedules, often quite quickly. These should be...
Management of the Transport Infrastructure Development Programme in the Czech Republic
Radek Novak
Communications - Scientific Letters of the University of Zilina 2000, 2(4):95-99 | DOI: 10.26552/com.C.2000.4.95-99
The article deals with problems of the transport infrastructure in the Czech Republic in all branches and modes of transport. There are discussed some details of the essential principles of the global national project "Transport Infrastructure Development Programme in the Czech Republic". This is the principal focus of this article. The article is based on various materials and documents of different management levels - especially those of the Ministry of Transport and Communication of the CR. These documents are summarised in the Programme. The article is focused mainly on the explanation of the future trends of rebuilding and modernisation of the...
Profile of the Best World Logistics Practice
Jaroslav Kral
Communications - Scientific Letters of the University of Zilina 2000, 2(4):100-107 | DOI: 10.26552/com.C.2000.4.100-107
The paper deals with an issue of supply chain management that is a trend in integrated logistics enterprise management. It gives a synthesised view on current logistics management practice of the best World companies. It defines reasons of supply chains genesis, conditions of an implementation and environment of operations improvements. Also it justifies an importance of information technologies, information systems and the Internet place here. The paper indicates the most important problem for solving is supply chain inventory to be minimised.