Communications - Scientific Letters of the University of Zilina, 2013 (vol. 15), issue 1
Articles
The Shrinking and Expanding Heuristic for the Fleet Size and Mix Vehicle Routing Problem
Urooj Pasha, Arild Hoff, Arne Lokketangen
Communications - Scientific Letters of the University of Zilina 2013, 15(1):6-13 | DOI: 10.26552/com.C.2013.1.6-13 
The FSMVRP (Fleet Size and Mix Vehicle Routing Problem) is a variant of the classical Capacitated Vehicle Routing Problem, CVRP. We suggest a new methodology, called the Shrinking and Expanding Heuristic (SEH) which is incorporated in a standard tabu search. To determine an appropriate fleet mix is a major challenge in this type of problem and the SEH technique is especially developed to find a good combination of vehicles by introducing a mechanism for changing the existing fleet mix during the search, thus also changing the underlying route structure. The SEH utilizes the concept of depletion and expansion of routes depending upon the filling degree...
Proportionally Fairer Public Service Systems Design
Lubos Buzna, Michal Kohani, Jaroslav Janacek
Communications - Scientific Letters of the University of Zilina 2013, 15(1):14-18 | DOI: 10.26552/com.C.2013.1.14-18
This paper focuses on the utilitarian solution of public service system design problem, obtained when maximising the sum of all utilities and proportionally fair-like solution, taking into account proportional changes in individual utilities. As an archetypal example of the optimisation problem, we are examining the weighted p-median problem, which is solved by the primary-dual based procedure. We use realistic largescale data describing the road network and spatial distribution of population. By comparing the resulting solutions, for selected range of parameters, we evaluate how costly it is to consider fairness criteria in the service system design....
Route Selection and Scheduling for Urban Public Bus Transportation
Ugur Cetin, Nurbanu Ince, Pelin Bayindir, Secil Savasaneril
Communications - Scientific Letters of the University of Zilina 2013, 15(1):19-24 | DOI: 10.26552/com.C.2013.1.19-24
In Turkey, municipalities provide a major portion of the city public transportation service. Since the service has to be provided potentially to every resident, and at a low price, municipalities are often left struggling with negative balance. This implies that operating under low cost is essential for survivability. We conduct a study to analyze the public bus transportation system in Ankara which is the capital city of Turkey. The analysis reveals that there exist inefficiencies in the service due to fleet allocation, routing, dispatch frequency, and scheduling of the vehicles. Considering the daily and hourly transportation needs of the passengers,...
On a Fair Fare Rating an a Bus Line
Stanislav Paluch
Communications - Scientific Letters of the University of Zilina 2013, 15(1):25-28 | DOI: 10.26552/com.C.2013.1.25-28
Suppose we are given along bus line with asingle tariff. Some passengers travel along long distances while another ones along short trips. Such asingle tariff is advantageous for the first mentioned passengers. However, asingle tariff is inconvenient for short trip passengers. Babel, Keller, Hamacher and Schobel tried to solve this problem by dividing serviced area into zones in [1], [2] and [3]. Kohani presented similar attitude in [4]. Another way how to improve fairness is to introduce a double tariff - fare x for passengers traveling at most along k laps and fare y for passengers traveling along more than k laps. This paper shows how to determine...
Designing of Zone Tariff in Integrated Transport Systems
Michal Kohani
Communications - Scientific Letters of the University of Zilina 2013, 15(1):29-33 | DOI: 10.26552/com.C.2013.1.29-33
When designing a tariff system, there are several possibilities how to design the tariff. One of them is dividing the region into the zones. These zones are usually created by stops in one or more municipalities and the price of travelling between arrival and destination stops is determined by the number of travelled tariff zones by the passenger. There are various approaches how to design prices in such a system. In this article we introduce a mathematical model of the tariff zones design based on counting zones and introducing two approaches for designing prices within this system. We will focus on solving this problem using a universal optimisation...
Optimal Assignment of Vehicles to Urban Transport Routes
Dusan Teichmann, Michal Dorda, Ivana Olivkova
Communications - Scientific Letters of the University of Zilina 2013, 15(1):34-38 | DOI: 10.26552/com.C.2013.1.34-38
The article deals with solving a concrete problem occurring in the tramway net conditions in Ostrava urban mass transport. Nowadays acertain tramway set is in the traffic, where different vehicle types in terms of the capacity are assigned. For every route, one vehicle type is used. Information about the offered capacity and the passenger flows per hour is known. But the existing assignment of vehicles to single routes causes agreater discrepancy in terms of offered places and passengers' demand. The discrepancy can be measured by means of the ratio of these values on the most frequented route section. The discrepancy is characterized so that the ratios...
Mathematical Programming vs. Constraint Programming for Scheduling Problems
Ludmila Janosikova, Tomas Hreben
Communications - Scientific Letters of the University of Zilina 2013, 15(1):39-43 | DOI: 10.26552/com.C.2013.1.39-43
This paper focuses on a classical scheduling problem known as the job-shop scheduling problem which is one of the most difficult problems in combinatorial optimisation. The paper presents two solution techniques, namely mathematical programming and constraint programming and compares their computational efficiency on benchmark problems. In addition, the experience with scheduling trains in a passenger railway station is presented. The computational experiments proved that the mathematical programming approach outperforms constraint programming with respect to the quality of the solution.
Evaluation of a Heuristical Algorithm for Transit Line Planning
Juraj Cenek
Communications - Scientific Letters of the University of Zilina 2013, 15(1):44-48 | DOI: 10.26552/com.C.2013.1.44-48
Transit line routing is apart of strategic planning of transportation services in aregion. As such it is vital for providing services of astandard quality for an acceptable price. From a mathematical point of view line planning is an NP hard problem which is difficult to solve and so mostly heuristic methods or an interactive approach supported by simulations are used. The paper describes shortly a new heuristic algorithm, evaluates its quality on a design of set of regional lines and compares the designed plan with a current transportation services in a real region chosen as an example.
Keeping Jigsaws Connected
Johan Oppen
Communications - Scientific Letters of the University of Zilina 2013, 15(1):49-53 | DOI: 10.26552/com.C.2013.1.49-53
This paper describes a combinatorial problem where the idea is to find out in how many ways a jigsaw puzzle can be built, piece by piece, in such a way that it stays connected at all times during the building phase. Computational methods, both exact and approximate, to count the number of such connected sequences are presented.
Value of Stock Level Information and Impact on Manufacturers' Substitution Decisions
Nursen Tore, Secil Savasaneril, Yasemin Serin
Communications - Scientific Letters of the University of Zilina 2013, 15(1):54-61 | DOI: 10.26552/com.C.2013.1.54-61
In this work, we study the product substitution decisions of amanufacturer that produces multiple items. We first quantify the cost savings due to flexibility attained through substitution. Ideally, the manufacturer must use the stock level information when giving production, scheduling and substitution decisions. In practice however, such decisions are often given ignoring the available information. In this work, we also address the importance of using stock level information by quantifying its value. Results show that using stock level information is critical especially when taking production scheduling decisions.
Multi-Stage Discrete Programming of the Production Line
Robert Bucki, Franciszek Marecki
Communications - Scientific Letters of the University of Zilina 2013, 15(1):62-67 | DOI: 10.26552/com.C.2013.1.62-67
The paper highlights the problem of multi-stage optimization consisting in determining a timescale of realization orders of objects. Each production stage requires solving a multi-stage discrete programming problem. Production is optimized from the given state of the line to the state in which the line capacity does not allow any further manufacturing. Tools to be replaced in production aggregates are determined by means of heuristic algorithms. Optimization of the manufacturing line is brought to the discrete linear model within each stage.
Hepatitis B Disease Diagnosis Using Rough Set
Tomasz Kanik
Communications - Scientific Letters of the University of Zilina 2013, 15(1):68-73 | DOI: 10.26552/com.C.2013.1.68-73
This paper describes processing of the medical data by means of the prediction system based on Rough Set Theory (RST). The Rough Sets proved to be very useful for the analysis of the decision problems concerning objects described in a data table by a set of condition attributes as well as a set of decision attributes. In order to make efficient data analysis and suggestive predictions in a case of the data of patients suffering from viral hepatitis were used to predict a probability of their death or serious disability. This paper also demonstrates an extension of the Rough Set methodology for reducing number of input data in order to increase prediction...
Coordination of Bus Departures by Mathematical Programming
Lydia Gabrisova, Petr Kozel
Communications - Scientific Letters of the University of Zilina 2013, 15(1):74-79 | DOI: 10.26552/com.C.2013.1.74-79
This paper deals with coordination of bus arrivals. A quality criterion of this problem is to minimize waiting time of passengers, to make public transport more attractive. One possibility for solving is to increase the number of arrivals with associated investments. Another possibility, without investment, is the coordination of bus arrivals. The latter possibility is analyzed and solved in this paper. Mathematical formulation of this problem leads to a quadratic programming model which is hard to solve. Our approach is based on piecewise linearization of the quadratic objective function. This integer programming model enables to include to the problem...
Effects of Atmospheric Corrosion on the Car Park Roof Structure
Vincent Kvocak, Renata Vargova, Pavol Beke, Eva Terpakova
Communications - Scientific Letters of the University of Zilina 2013, 15(1):80-87 | DOI: 10.26552/com.C.2013.1.80-87
The effects of the outdoor climatic conditions are observed in all constructions. Steel members of such constructions are affected negatively by urban atmospheres in a synergy with the effects of industrial pollutants. In very exposed buildings the impact of such effects is so significant that diagnostic assessment of their state and technical expertise is required. The paper presented shows the actual state assessment and the verification of structural reliability of the existing load-bearing structure of an exterior car park roof, emphasizing the estimation of corrosion losses in the steel structure that have considerably lowered its lifespan and...
Energy and Environmental Evaluation of the Selected Wooden Family Houses
Pavol Durica, Silvia Badurova, Radoslav Ponechal
Communications - Scientific Letters of the University of Zilina 2013, 15(1):88-95 | DOI: 10.26552/com.C.2013.1.88-95
Existing buildings are responsible for over 40 % of the world´s total primary energy consumption (data from IEA). The EU adopted the Energy Performance of Buildings Directive [1], which obliges Member States to reduced 20 % in greenhouse gas (GHG) emissions by 2020 compared with 1990 levels, a 20 % cut in energy consumption through improved energy efficiency by 2020 and a 20 % increase in the use of renewable energy by year 2020. The Directive also requires Member States to ensure that, after year 2020, all new buildings in the EU will have to consume “nearly zero” energy. Slovakia has excellent availability of wood and therefore...
Integrated Safety Implications for Project Management
Michal Vanek, Yveta Tomaskova, Michal Senovsky, Lucie Krcmarska
Communications - Scientific Letters of the University of Zilina 2013, 15(1):96-102 | DOI: 10.26552/com.C.2013.1.96-102
Safety insurance provisions in the broadest sense of the term belong among major tasks and challenges for a company management as wellas any municipality administration. In the framework of the decision making process, the manager or administrator takes into account a lot offactors, among which - apart from safety risks - financial possibilities of the company or municipality are of major importance. The decisionsmade have a project character, and managers and administrators can take advantage of project management tools to be able to assess viabilityof the decisions suggested, as well as their implementation. This paper concentrates on the prior-to-investment...
A Multipurpose Robotic Vehicle for the Rescue of Persons and Interventions in Emergency Situations
David Rehak, Ales Dudacek, Pavel Polednak
Communications - Scientific Letters of the University of Zilina 2013, 15(1):103-109 | DOI: 10.26552/com.C.2013.1.103-109
At present, multipurpose robotic vehicles represent the best possible solution for the rescue and transport of persons in a state of traumafrom places in difficult-to-access terrain, in poor weather conditions and in emergency situations. It is a case of complementary means supplementingthe equipment for rescue and emergency response that already exists or is being developed on the basis of a concept drawn in theframework of Integrated Emergency System of the Czech Republic. As a multipurpose means, the vehicle can be used for unmanned remoteinvestigations into situations, for unmanned rescue and materials transport. Simultaneously, a modification...