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Mohammad Reza Jelokhani-Niaraki, Ali Asghar Alesheikh, Abbas Alimohammadi, Abolghasem Sadeghi-Niaraki
2010 (Vol 22), Issue 6
In recent years, the development of the GIS-T (Geographic Information System for Transportation) applications has gained much attention, providing the transportation planners and managers with in-depth knowledge to achieve better decisions. Needless to say, developing a successful GIS for transportation applications is highly dependent on the design of a well-structured data model. Dynamic segmentation (DS) data model is a popular one being used more and more for different GIS-T analyses, serving as a data model that splits linear features into new set of segments wherever its attributes change. In most cases, the sets of segments presenting a particular attribute change frequently. Transportation managers place great importance on having regular update and revision of segmented data to ensure correct and precise decisions are made. However, updating the segmented data manually is a difficult task and a time-consuming process to do, demanding an automatic approach. To alleviate this, the present study describes a rule-based method using topological concept to simply update road segments and replace the manual tasks that users are to carry out. The proposed approach was employed and implemented on real road network data of the City of Tehran provided by the Road Maintenance and Transportation Organization (RMTO) of Iran. The practical results demonstrated that the time, cost, human-type errors, and complexity involved in update tasks are all reduced. KEYWORDS: GIS-T, dynamic segmentation, segment, automatic update, change type, rule

Peter Matis
2010 (Vol 22), Issue 6
In recent years the providers of logistic services are under big pressure to lower their expenses and improve their quality. One way of accomplishing this task is the centralization of logistic activities. The paper presents possible methods for restructuring the distribution network on the case of Slovak Post p.l.c. By reducing the number of centres for distribution and by creating larger centres one can expect improvement in the process efficiency. There is no simple method to find the optimal distribution network. One possible way to tackle this problem is to use aggregation methods to group customers on the micro and macro levels. Several aggregation methods, including two new ones are presented and compared for the centres’ and delivery districts. New measurements for the quality of aggregation are created and tested on real data using all the discussed aggregation methods. KEY WORDS: network creation, aggregation, quantitative methods, fuzzy logic, distribution districts

Dino Županović, Mario Anžek, Goran Kos
2010 (Vol 22), Issue 6
Road traffic safety is a complex system which combines movement of entities in precisely determined space and time dimension. Each of the entities, with their different properties, sets different requirements to road traffic system, including also other entities. Due to the large number of entities and their characteristic requirements, their interaction results in extremely complex relations which determine the behaviour of the road traffic system. The entities are combined according to their common features into certain groups, the movements of which usually result in conflicts. In such situations it is necessary to ensure the movement of a group of entities. This method of insurance necessarily creates negative consequences for all the entities that participate in road traffic system. In order to mitigate as much as possible these consequences, it is necessary to find an adequate method of optimising road traffic system according to a given criterion. The paper uses the results of the analysis of more than 100 road traffic system models and presents the methodology of determining the level of their interconnection. The level of influence of the basic traffic values on the final effect, i.e. the possibility of optimising signal-controlled intersections has been found and described. KEYWORDS: traffic flow, signalized intersection, pretimedsystem, optimization, 2-phase system, 4-phase system, volume-to-capacity, lost time

Marinko Jurčević, Frane Mitrović, Mila Nadrljanski
2010 (Vol 22), Issue 6
This paper deals with the application of System dynamics and Chaos theory in shipping using the example of freight rate forming. The development of new technologies, changes in structure and conditions, information accessibility, etc. are only some of the factors that intensify changes in freight rate forming in shipping. Therefore, shipping environment is becoming increasingly complex and dynamic. System dynamics seems to be a tool very suited for modelling of strategic and operational behaviour in shipping business. Due to the complex behaviour of these systems, chaos theory can also help in modelling of processes in shipping. The basic feature of chaotic systems is fine sensitivity in conditions at the beginning, when small change in input value may cause great changes in output values. By applying its concepts to the business process, as well as in freight rate forming in shipping, it prepares the business systems for quick response to the changes in the environment. KEY WORDS: chaos theory, shipping, freight rate, system dynamics

Davor Sumpor, Jasna Jurum-Kipke, Dalibor Petrović
2010 (Vol 22), Issue 6
While operating a locomotive or a railcar the engine drivers are exposed to the action of several simultaneous factors of disturbances from the traffic environment, and therefore their reliability and safety are reduced. The human-determined physical, sensor and cognitive factors are not only the attributes of the engine driver, but also include influences from the traffic environment, due to the interaction in the “engine driver – traffic means – traffic environment” system. Traffic environment is defined in such a way that, among other things, it includes also the working environment of the drivers cab and the recent traffic situation. The action of factors of temporary subjective disturbances and/or permanent psychological and physiological changes, depend not only on the individual endurance of engine drivers, but also significantly on the type of locomotive or railcar operated by the engine driver, as well as on the fact whether the traffic is intended for the transport of passengers and/or freight, or a shunting engine is involved. The ergo-assessment based on a survey of 50 respondents yielded the final results that are almost identical to the results of ergo-assessment obtained during the formation of the methodology of cognitive ergo-assessment on a sample of 31 respondents. In both cases the surveyed respondents were engine drivers who in practice operate all types of locomotives and railcars, who have acquired engine driver secondary school qualifications and have passed vocational testing for all types of locomotives and railcars. Systemic ergo-assessment of the intensity of the overall psychophysical effort is possible by introducing the index of importance which is used in case of all engine drivers to integrally and equally recognise also the influence of the percentage of occurrence of a certain factor of subjective disturbance and influence of the average assessment of the subjective disturbance intensity, thus allowing an insight into the structure of a system of simultaneous ergo-assessment factors and isolation of ten dominant ergo-assessment factors. Partial cognitive ergo-assessment and inter-comparison of the intensity of subjective disturbances have indicated the types of locomotives and/or railcar compositions in which the maximum partial intensity of disturbance is due to the following factors regarding the working ambient of the drivers cab: visibility, intensity of the difficulty of operation, and intensity of disturbance of the audible traffic noise. KEY WORDS: traffic environment, cognitive ergo-assessment, dominant factors of subjective disturbances, assessment parameters, safety and reliability

Robert Maršanić, Zdenka Zenzerović, Edna Mrnjavac
2010 (Vol 22), Issue 6
The demand for parking services is not a constant one, but rather varies from minimum to maximum. The range between the maximum and minimum demands and the dynamics of changes are the basic factor influencing the required size of the parking area capacity and the respective financial effects. The objective of this paper is to demonstrate that the queuing theory can be implemented in defining the optimal number of serving places (ramps) and the required capacity (number of parking spaces) in controlled access parking areas and that the established model can serve in business decision-making in respect to planning and development of the parking area capacity. The presented model has been verified in the example of the “Delta” parking area in the City of Rijeka but this model is particularly valuable as it can be implemented in any controlled access parking areas, i.e., parking areas with toll-bars under current or any other changed future conditions. KEY WORDS: planning of parking area capacities, optimal parking area capacity, queuing theory, parking area as a queuing system

Ljubiša Kuzović, Dražen Topolnik, Draženko Glavić
2010 (Vol 22), Issue 6
The purpose of this paper is to define factors that influence the emergence of induced i.e. generated traffic for experts involved in highway feasibility studies. An explanation of the practical methods for forecasting generated traffic is done by reviewing international experiences in the relevant literature. Also, the idea underlying this paper is to explain the different treatments of generated traffic in evaluating highway projects with no tolls, which is based on socio-economic aspects versus the evaluation of highway projects with tolls, which is based on financial aspects. Finally, we propose that since it is hard to measure the economic benefits from indirect effects (in the evaluation of socio-economic aspects) the evaluators could determine the economic benefits of the generated traffic using the same procedure as for normal traffic. KEYWORDS: induced traffic (generated traffic), normal traffic, coefficient of elasticity, time savings, vehicle operating cost (VOC) savings, the economic surplus

Josip Zavada, Jasna Blašković Zavada, Katica Miloš
2010 (Vol 22), Issue 6
Big cities in the world are burdened by heavy traffic and all the resulting negative consequences. A partial solution of this problem is achieved by the introduction of high-quality public urban transport of passengers that enables faster and more efficient transport. Since the introduction of individual forms of public urban transport depends on several factors, such as economic, traffic, environmental and technical ones, the problem is often a very complex one. The implementation of trolleybuses represents one of the forms of passenger transportation in public urban transport. It is the most favourable electrical vehicle for public urban transport when the implementation of a rail system is not affordable. Looking through history, the trolleybus has experienced significant changes in the implementation, in a large number of world urban environments. This paper points out the unjustifiable neglect of trolleybus in the implementation for the public urban transport and the renewed increase in the interest for its implementation. The advantages and drawbacks of the trolleybus are listed in relation to buses, as well as the reasons due to which some cities in the world are introducing it or increasing its implementation. The paper also emphasises and provides arguments of the ecological and energy advantages of trolleybuses in relation to buses as crucial in advanced public urban transport of passengers. Also, advanced technical solutions are pointed out that contribute to safer, faster and more comfortable transport of passengers. KEY WORDS: trolleybus, bus, public urban transport, environment, economics

Xiaojun Yu, Hai-Jun Huang
2010 (Vol 22), Issue 5
This paper investigates the efficiency loss of selfish routing simultaneously with user equilibrium (UE) player and Cournot-Nash (CN) players. The upper bound of the efficiency loss of UE-CN mixed equilibrium with polynomial cost functions is obtained by the scaling method and the nonlinear programming method, respectively. It is shown that the upper bound of efficiency loss obtained by the scaling method only depends on the polynomial degree of the link travel cost function and the upper bound of efficiency loss obtained by the nonlinear programming method depends on the number of the CN players besides the aforementioned factors. The numerical tests validate our analytical results. KEY WORDS: efficiency loss, UE-CN mixed equilibrium, variational inequality, selfish routing game

Urša Horvat
2010 (Vol 22), Issue 5
The aim of this paper is to present the possibility of introducing the motorway of the sea to the Port of Koper. Based on the present situation in the Port of Koper and the planned extension of the container terminal determined by the development plans of the Port of Koper, the paper presents the increase in the container transhipment due to the introduction of the motorway of the sea and its influence on the hinterland infrastructure. For this purpose a simulation was introduced which shows the increase in container transhipment and its distribution between the road and railway part of the container terminal until the year 2015. The maximum capacity of the road and railway part of the container terminal presents two critical points which would be reached due to the introduction of the motorway of the sea to the Port of Koper. The consequence would be a change in the distribution ratio of transhipment between road and railway part of the container terminal. This would overturn the desired ratio of 30:70 (road: railway) determined by the guidelines of the White Paper. KEY WORDS: Motorway of the sea, Port of Koper, container transhipment

Mirjana Kovačić
2010 (Vol 22), Issue 5
In this paper, the author presents the multi-criteria analysis methods, PROMETHEE I and II and GAIA, used for selecting the location of a nautical tourism port. In an example of the selected location of a nautical tourism port in the Northern Adriatic, the author has used an analytic and graphical evaluation for solving such a problem. Particular attention has been paid to the use of GAIA method, which is suitable for visualisation of the problem characteristics through geometrical interpretation and presentation of the results of a multi-criteria analysis. By application of the described methods, it is possible to establish the most acceptable location considering the principles of sustainable development. The paper emphasises the importance of applying multi-criteria analysis and multi-criteria use of selected methods, which contain criteria and sub-criteria for selecting the optimal location of a nautical tourism port. In the paper the results of the research “Criteria for selecting the location of a nautical tourism port” conducted during 2006/2007 have been used. KEY WORDS: nautical tourism port, selecting the location, multi-criteria analysis

Darja Topolšek, Anton Čižman, Martin Lipičnik
2010 (Vol 22), Issue 5
Collaborative behaviour and various aspects of comparing collaboration with coordination and cooperation present the basis for more detailed assumptions concerning the importance of integrating logistic function with the marketing function. The collaborative behaviour dimension of inter-functional integration presents a system of mutual visions, decision-making and collective responsibility to provide results, services or a product. Logisticians often define integration within the framework of the supply chain, yet they neglect the internal integration or the integration between individual departments or functions in a company. Defining internal integration and its level as well as the connection with the level of collaborative behaviour is the basis of the research part of this paper. The quantitative research part studies whether and to what extent collaborative behaviour influences the level of internal integration between logistic and marketing functions. The research is based on a quantitative analysis of results of the survey that was conducted in Slovene retail companies. KEY WORDS: logistics, marketing, logistic function, marketing function, internal integration, collaborative behaviour, inter-functional relations

Alok Mishra, Deepti Mishra
2010 (Vol 22), Issue 5
Recently, Radio Frequency Identification (RFID) has received considerable attention and is considered to be the next wave of information technology revolution. The number of RFID applications in different industries is increasing continuously. Cumulative sales of RFID tag is up in 2006 which shows RFID adoption trend in industries to improve their efficiency of operations and to gain a competitive advantage. In the aviation industry, major airports, airlines have been also planning the RFID adoption in baggage handling and customer services areas for a long time. Many pilot tests have been performed at various airports and RFID tags were found to be far more precise along with better performance than bar codes. This paper provides a review on RFID systems, associated technology, advantages, limitations and applications in various fields. Further, this paper reports the preliminary review of state of RFID adoption planning, architecture and implementation plan in a major airline, focusing on improved baggage handling, increased airport/airline security and customer services. KEYWORDS: aviation, airline, baggage handling, customer-service, Radio Frequency Identification (RFID)

Pero Vidan, Josip Kasum, Marijan Zujić
2010 (Vol 22), Issue 5
In maritime traffic, a route is one or more known tracks along which navigation takes place or there is intention to sail. Meteorological factors are important if the route exceeds the distance of 1500M [1]. Meteorological navigation is the selection of a navigational route in view of meteorological factors and control of vessel during heavy weather conditions and safe navigation aimed at the protection of human lives, vessels and cargo during heavy weather. The paper proposes a model of grouping and evaluating estimates of meteorological factors when planning meteorological navigation. It is advised to upgrade the Electronic Chart Display and Information System – ECDIS program with the aim of allowing for the computer planning of meteorological navigation. KEY WORDS: planning of navigation, meteorology, optimal route, Electronic Chart Display and Information System - ECDIS

Bojan Hlača, Dušan Rudić, Saša Hirnig
2010 (Vol 22), Issue 5
The economic situation and comparative advantages of the Port of Rijeka are no more than important preconditions of its development and competitive ability. No adequate connection of the Port of Rijeka to its catchment area is possible without a modern rail and road traffic. The researches and analyses of the port hinterland connection current state, the results of which are provided in these documents, clearly indicate the need to upgrade the existing railway tracks and build a new level Rijeka – Zagreb railway line. This line is a vital condition for ensuring both, a strong growth of the port performances and its competitive ability vis-a-vis other neighbouring ports. The level railway line Rijeka – Zagreb with Rijeka railway junction adequately upgraded, should be therefore regarded as strategic traffic project and conditio sine qua non for the future development of the Port of Rijeka. However, no solution of the Rijeka railway junction problem will be possible without finding the right way for better connection of some of the port terminals. When considering the integral solution of the rail traffic in the greater Rijeka Basin, it is important to know that the access to individual port terminals, the connection with the railway in Istria through the Učka Tunnel and connection with the port terminals on the Island of Krk are of great importance for the Port of Rijeka future development. The efforts to recognize the problems in the port environment and define priorities that make the rail transport a key factor of the Port of Rijeka’s future growth, are the main contributions of this study. KEY WORDS: Port of Rijeka, traffic connections, rail traffic, Rijeka railway junction, development guidelines

Mladen Nikšić, Slaven Gašparović
2010 (Vol 22), Issue 5
The paper studies the ropeways as a special subgroup of land traffic system from the interdisciplinary aspect of the traffic sciences and geography. The ropeways have seen a propulsive technical and technological development over the last several decades. Therefore, the paper gives an overview of the types of ropeways with special emphasis on the technologically most advanced ropeways. Regarding the lack of studies on the ropeway issues in Croatia, the space distribution of ropeways in the Republic of Croatia has been analysed. The ropeways, as well as other transport modes, affect the space, and since ropeways are considered environmentally friendly traffic modes, their impact on the environment is analysed, both in the mountains and in the cities. Moreover, the economic influence of ropeways on the surrounding area is studied as well. KEY WORDS: ropeway, surface lift, aerial ropeway, chairlift, gondola, funicular

Patricija Bajec, Igor Jakomin
2010 (Vol 22), Issue 4
Should firms perform logistics services on their own or should they buy them from a logistics provider? Today’s global competition forces companies to re-evaluate their existing processes, technologies and services in order to focuse on strategic activities. Outsourcing is now increasingly used as a competitive weapon in today’s economy. External parties can often do job quicker, cheaper and better. This has resulted in an increasing awareness of the importance of the make-or-buy decision, the dilemma organisations face when deciding between keeping logistics services in house or purchasing them from an outside logistics provider. This article provides a make-or-buy decision process methodology that any manager can implement – whatever the size or industrial type of the organization. The make-or-buy methodology is one of the most critical strategic decisions within logistics outsourcing and should be taken in a structured and consistent manner. A practical guide to this decision is a step-by-step guide to addressing make-or-buy decision in a consistent and structured manner. The high-level steps are as follows: • evaluate whether outsourcing is right for your company; • determine exactly what functions to outsource and the performance expectations; • use a well-defined professional selection process to evaluate and select which provider(s) are right for the job. KEY WORDS: logistics, logistics outsourcing, make-or-buy decision, outsourcing methodology

Shuguang Li, Qing-Hua Zhou, Yongfeng Ju
2010 (Vol 22), Issue 4
In order to solve the system optimum dynamic traffic assignment problem, the whole link model with physical queue is used to formulate the single destination system optimum dynamic traffic assignment problem as a mixed linear program. A relationship between the cumulative curves and the wave speed presented by Newell (1993) is used to present a dynamic network model in considering spillback queue. And nonlinear constrains are relaxed into mixed linear constrains; the linear program software is used to solve the system optimum dynamic traffic assignment problem. A numerical example illustrates the simplicity and applicability of the proposed approach. KEYWORDS: Dynamic System Optimum Traffic Assignment; physical queue; mixed integer linear programming

Igor Trupac, Elen Twrdy
2010 (Vol 22), Issue 4
With the European Union growing eastwards and with the establishment of important production facilities in the countries of Central and Eastern Europe, the hinterland potential is bound to grow even more. The strategic goal of the Port of Koper is to become one of the best ports in the Southern Europe, to develop from a handling port into a commodity distributional centre. Penetrating and exploiting these markets demands cooperation (integration) with the existing inland terminals (logistic centres) and establishing of new ones positioned between Eastern and Western Europe. This paper aims to present and analyse: (I) supply chains of the flow of goods through the Port of Koper to/from the countries of Central and Eastern Europe, (II) the current state and strategies to optimize the flow of goods, (III) market potential, investments in new terminals and capacities. KEY WORDS: Port of Koper, strategies, goals, supply chains, integration, new terminals, market potential, investments

Rajko Horvat, Berislav Barišić-Jaman, Gordan Mršić, Igor Špoljarić, Andro Vrdoljak, Ivan Pehar
2010 (Vol 22), Issue 4
One of the measures to increase road traffic safety in Croatia is the introduction of obligatory use of daily lights on vehicles in road traffic during driving, regardless of the visibility and the time of day. The paper describes the new original technical and technological procedure of analysing automotive light bulbs in order to find the traces of glass particles of the broken glass balloon in the marginal cases of action of small inertia forces generated as result of a traffic accident. Investigations of light bulbs in traffic accidents had been rarely done before; therefore the subject of this scientific research is the analysis of the light bulb filament used in automobiles to light the road ahead and to give light signals, i.e. all the light signalling devices on the automobile using the new technical and technological procedure by means of SEM/EDX method. The scientific research has improved the investigation procedure in analysing the light bulbs on automobiles in determining whether at the moment of the traffic accident the regulatory lights were switched on. In determining the responsibility of participants for causing the traffic accident, such a fact may sometimes be of crucial significance. KEY WORDS: traffic accident, light bulb, technical and technological procedure, lights in traffic, microscope, molten glass particles

Pero Škorput, Sadko Mandžuka, Niko Jelušić
2010 (Vol 22), Issue 4
The paper analyses the real-time detection of incidents in road traffic. A general model is presented of an integral road traffic incident management system. The paper presents the major incident detection methods. The detection procedure on open highway sections has been dealt with in particular. Adequate mathematical model has been defined, as the base for the realisation of the estimators of the traffic flow condition variables. The proposed method is the Extended Kalman Filter. The final part of the paper deals with an example for the realisation of the Incident Management Decision Support System (IMDSS). KEY WORDS: intelligent transport system, incident management system, traffic model in the status space, theory of estimation, extended Kalman filter, automatic incident detection, decision support system

Sanja Steiner, Tomislav Mihetec, Ana Božičević
2010 (Vol 22), Issue 4
In the forthcoming period the European air traffic management will handle double flight operations than today – from 1.7 to 2.1 higher traffic level in 2025 than in 2005 [1]. The problem of the European airspace fragmentation should be solved by the comprehensive dynamic harmonization programs, which can contribute to effective increase of airspace capacity and increase of air transport efficiency. The main objective of the development strategy refers to the implementation of reformation processes of the European air traffic management system through functional ATM1 regionalization. Encouraged by the Single European Sky project, and through airspace de-fragmentation, numerous projects have been initiated by Eurocontrol in cooperation with the European Commission. One of them is establishing of the Functional Airspace Block in South Eastern Europe. The implementation of regulatory, institutional and legal framework of the Single European Sky FAB2 would ensure the expansion of the European air traffic market to South Eastern Europe, counting over 500 million potential users [2]. Croatia and all the other countries in the region have to adopt the provisions of ECAA3 Agreement and EU air transport acquis in their national legislation. This paper specifies the main determinants of the strategic development as well as the key factors which influence the European air traffic dynamics. The paper elaborates the indicators and significant elements of the required ATM reforms in South Eastern Europe on the samples of six ANSPs according to ECAA Agreement and EU acquis. KEYWORDS: Single European Sky, European Common Aviation Area, Air Traffic Management, South Eastern Europe, Functional Airspace Block

Nikolina Brnjac, Borna Abramović, Marinko Maslarić
2010 (Vol 22), Issue 4
The increase of market share of railway in cargo transport on Corridor X is considered a precondition in order to make railway operation cost-effective and commercially attractive to private operators. Railway sector has suffered damage during the war and the infrastructure needs modernization in order to create efficient and environmentally-friendly transport modes. The intervention is necessary in order to allow the railway network to be successful in the corridor competition. The forecasting model would be used to forecast the requirements for intermodal transport by the year 2018 on Corridor X using forecasting model for the future of the development of cargo transport requirements on Corridor X. KEY WORDS: intermodal transport, cargo flows, transport forecast

Pero Tabak, Slobodan Kaštela
2010 (Vol 22), Issue 4
The paper compares the EU Postal Directives (97/67/EZ and 2002/39/EZ) in a consolidated text and the respective parts of the Croatian legislative frame with the aim of harmonising the national postal system with EU. Both regulatory frames are presented, as well as objectives and scopes, types of postal services (particularly the universal ones), reserved area, necessary conditions governing the provision of services, tariff principles, insurance of market competition through transparency of financing and separation of the accounting system, desired quality of universal services, harmonisation of technical standards and obligations of national regulatory authorities. By presenting individual chapters of the Post Directives, some specific solutions of the Croatian regulatory framework have been indicated and uncertainties which result from the comparison analysis of the European Postal Directives and the Croatian legislation as well as the influence of these documents on the postal traffic technology. KEY WORDS: EU Postal Directives, Croatian postal regulatory frame, universal services

Sergej Težak, Zdravko Toš, Ivo Jurić
2010 (Vol 22), Issue 3

This paper examines the reliability of the operation of cableway systems in Slovenia, which has major impact on the quality of service in the mountain tourism, mainly in wintertime. Different types of cableway installations in Slovenia were captured in a sample and fault tree analysis (FTA) was made on the basis of the obtained data. The paper presents the results of the analysis. With these results it is possible to determine the probability of faults of different types of cableways, which types of faults have the greatest impact on the termination of operation, which components of cableways fail most, what is the impact of age of cableways on the occurrence of the faults. Finally, an attempt was made to find if occurrence of faults on individual cableway installation has also impact on traffic on this cableway due to reduced quality of service.

KEYWORDS: cableways, aerial ropeways, chairlifts, ski-tows, quality, faults, fault tree analysis, reliability, service quality, winter tourism, mountain tourist centre

Danko Kezić, Anita Gudelj
2010 (Vol 22), Issue 3

Advanced function of the computer-based river traffic management system should automatically predict and prevent possible conflict and deadlock states between vessels by using adequate control policy (supervisor). This paper proposes a formal method for calculating maximally permissive deadlock prevention supervisor. To model the river system, the authors use a class of Petri net suitable for describing multiple re-entrant flowlines with disjoint sets of resources, jobs and control places, and matrix-based formal method to analyze the system. By using matrix algebra, the structural characteristics of the Petri net (circular waits, P-invariants, critical siphons and subsystem, key resource) have been analyzed and the steps for supervisor design proposed. The first and the second level deadlocks can be avoided by maintaining the number of tokens in the critical subsystems and ensuring that the key resource would not be the last available resource in the system. The derived supervisor has been verified by a computer simulation using MATLAB environment.

KEYWORDS: traffic management system, deadlock avoidance, discrete event system, Petri net

Željko Kurtela, Pavao Komadina
2010 (Vol 22), Issue 3

The ballast water exchange methods in open sea are, for the time being, the prevailing procedures accepted by shipowners. However, such methods do not guarantee full efficacy in elimination of allochthonous organisms. Besides, in some navigation zones, in particular in the closed seas, not even the criteria prescribed by international regulations can be fulfilled, i.e. the position of a ship exchanging ballast must be farther than 200Nm from the shore (alternatively 50Nm) at the sea depth exceeding 200m. Numerous research attempts on various treatment methods lead to the conclusion that there is still no scientific opinion on the final choice of methods for wide application on board. The treatment methods, such as hydrocyclone separation in the first stage and UV radiation in the second stage, stand a good chance for application on board. Advantages of such a combined method are in the very application of treatment that can be performed during all stages of ballast water treatment, i.e. loading ballast, voyage in ballast and discharging ballast. In closed seas and on shorter routes the operational advantages of hydrocyclone and UV radiation could be the prevailing factor for application. Within the research on the possible application of ballast water treatment by hydrocyclone and UV radiation, a pilot plant with hydrocyclone cluster and UV device was constructed. The research carried out on the pilot plant installed on board the m/v ‘’Naše more’’ proved the effectiveness of such ballast water treatment method and offered a new approach in using hydrocyclone for the inactivation of organisms by hydrodynamic forces. This approach has largely increased the efficacy of the device and a new method for utilization of hydrocyclone in ballast water treatment on board has been discovered.

KEY WORDS: ballast water treatment, hydrocyclone, UV radiation, application of method, pilot plant, hydrodynamic forces

Tomaž Tollazzi, Marko Renčelj, Vlasta Rodošek, Borut Zalar
2010 (Vol 22), Issue 3

In industrialized countries people over 50 years of age represent a rapidly growing part of population. Their lifestyle is also becoming more active, which means that the percentage of older drivers in the population of all drivers is also increasing. Many different studies have shown that elderly drivers are more frequently involved in specific types of accidents, especially at intersections.

In the past 15 years there was a trend of increasing popularity of roundabouts in Slovenia. Their introduction was generally supported by the arguments of increased traffic-flow capacity and traffic safety as well. The studies on which these arguments are based were performed with an “ideal” type of driver in mind; the one that fully understands new rules and reacts correctly in all situations that may occur at such intersections, where there are no light signals to guide them. An elderly person does not necessarily conform to that ideal and if the percentage of elderly drivers became significant, the premises of the above mentioned studies may not be correct anymore which in turn implies that their results could also be questioned.

The present study concentrated on the evaluation of traffic safety of elderly drivers, at various types of intersection, from their own perspective. Various statistical analyses of obtained data were performed. The most important finding was that we may claim, with high degree of probability, that the average person of the age of over 60 feels more unsafe at double-lane roundabouts than they would feel had the same intersection been equipped with traffic lights.

Elderly traffic participants will always cause more accidents or participate in them due to hazardous factors. Challenge, arising from many different studies and researches, is in studying what measures and solutions can reduce the risk for elderly participants.

KEYWORDS: traffic safety, road intersections, roundabouts, elderly people, older drivers

Yulong Pei, Yonggang Wang, Yin Zhang
2010 (Vol 22), Issue 3

With the development of microscopic traffic simulation models, they have increasingly become an important tool for transport system analysis and management, which assist the traffic engineer to investigate and evaluate the performance of transport network systems. Lane-changing model is a vital component in any traffic simulation model, which could improve road capacity and reduce vehicles delay so as to reduce the likelihood of congestion occurrence. Therefore, this paper addresses the virtual desire trajectory, a vital part to investigate the behaviour divided into four phases. Based on the boundary conditions, β-spline curves and the corresponding reverse algorithm are introduced firstly. Thus, the relation between the velocity and length of lane-changing is constructed, restricted by the curvature, steering velocity and driving behaviour. Then the virtual desire trajectory curves are presented by Matlab and the error analysis results prove that this proposed description model has higher precision in automobile lane-changing process reconstruction, compared with the surveyed result.

KEY WORDS: traffic simulation, lane-changing model, virtual desire trajectory, β-spline curves, driving behaviour

Andreja Križman, Anton Ogorelc
2010 (Vol 22), Issue 3

The purpose of this paper is to present the research results of a study conducted in the Slovene logistics market of conflicts and opportunism as disturbing factors while examining their impact on cooperation in logistics outsourcing performance. Relationship variables are proposed that directly or indirectly affect logistics performance and conceptualize the hypotheses based on causal linkages for the constructs.

On the basis of extant literature and new argumentations that are derived from in-depth interviews of logistics experts, including providers and customers, the measurement and structural models are empirically analyzed. Existing measurement scales for the constructs are slightly modified for this analysis. Purification testing and measurement for validity and reliability are performed. Multivariate statistical methods are utilized and hypotheses are tested. The results show that conflicts have a significantly negative impact on cooperation between customers and logistics service providers (LSPs), while opportunism does not play an important role in these relationships. The observed antecedents of logistics outsourcing performance in the model account for 58.4% of the variance of the goal achievement and 36.5% of the variance of the exceeded goal.

KEYWORDS: logistics outsourcing performance; logistics customer–provider relationships; conflicts and cooperation in logistics outsourcing; PLS path modelling

Deda Đelović, Dijana Medenica Mitrović
2010 (Vol 22), Issue 3

After theoretical considerations of organizational changes, the research findings were presented in relation to the following: the selection of the optimal model for implementation of organizational changes in the port that is subject of analysis and establishing of the character of the correlation between the organizational changes, the productivity level and the ship service time (components related to cargo handling operations). Through the implementation of AHP (Analytic Hierarchy Process) method, it has been identified that the optimal model for implementation of organizational changes in the studied port is restructuring. Starting from the relevant elements of the process model of productivity improvement, direct interdependency has been identified between the character of organizational changes and the level of productivity per full-time employee in the port, as well as the existence of correlation between the character of organizational changes, productivity level in the cargo handling process ship service time.

KEY WORDS: port, organisational changes, AHP method

Matjaž Knez, Bojan Rosi, Matjaž Mulej, Martin Lipičnik
2010 (Vol 22), Issue 3

In the age of global expansion of business operations and contemporary way of life the material and information flows in and between different companies are growing rapidly; they are thus becoming more and more difficult to manage. Had business functions in companies been dealt with separately until now (purchase, production, finances, sale, etc.), today the emphasis is placed on their integration due to their interdependence. By studying supply chains inside and between business partners, companies can gain competitive advantage and become more adjustable, taking the increasingly changing market circumstances into account. This enables them to meet consumers’ demands and expectations requisitely holistically. Taking all the crucial activities into account, the logistics management plays a key role in the companies facing the challenges of the new millennium. Based on the numerous megatrends, which influence each and every business entity, this article aims to explain the increasing strategic importance of logistics management. The latter may not be dealt with one-sidedly as a cost; moreover, the key aspects such as competitiveness as well as long–term existence of a company must also be considered. Innovation and systemic thinking in it and about it are needed.

KEY WORDS: logistics management, logistics strategy, supply chains, megatrends, innovation, systemic thinking

Čedomir Ivaković, Ratko Stanković, Mario Šafran
2010 (Vol 22), Issue 2
The problem of forming the distribution network results from the need to harmonize the characteristics of efficiency and efficacy of the supply chain with the corporate competition strategy. In this sense the possibility of optimising the distribution network has been presented (on a mathematical model) by applying the logistic outsourcing. The optimisation has been carried out using MS Excel software tools Solver. The results of the analysis have shown that possibilities for the reduction of distribution costs need to be searched for primarily in the domain of transport, in the target segment of the distribution network. The improvement elements have been achieved by outsourcing part of the supply chain, i.e. by introducing the cross-docking system which is managed by the external supplier of the logistic services. Quantitative changes, apart from the redistribution of the traffic of logistic and distribution centres and the reduction of logistic costs, have been reflected also in the geographical arrangement of distribution. The logistic outsourcing had dominant impact on the formation of the distribution network. KEY WORDS: distribution network, optimisation, logistic outsourcing

Ante Bukša, Ivica Šegulja, Vinko Tomas
2010 (Vol 22), Issue 2
By adjusting the maintenance approach towards the significant components of ship’s engines and equipment, through the use of operational data from the ship machinery’s daily reports, higher operability and navigation safety can be achieved. The proposed maintenance adjustment model consists of an operation data analysis and risk analysis. The risk analysis comprises the definition of the upper and the lower risk criterion, as well as the definition of a risk index. If the risk index is higher than the lower risk criterion, the component is significant, while it is not significant and has an acceptable risk index if the risk index is lower than the lower risk criterion. For each significant component with a risk index found to be “unacceptable” or “undesirable”, an efficient maintenance policy needs to be adopted. The assessment of the proposed model is based on data regarding the power engine original operation throughout a 13-year period. The results of engine failure examinations reveal that the exhaust valve is the most vulnerable component with the highest rate of failure. For this reason the proposed model of adjusting the maintenance approach has been tested on the exhaust valve sample. It is suggested that the efforts to achieve higher ship operability and navigation safety should go in the direction of periodical adjustments of the maintenance approach i.e. choosing an efficient maintenance policy by reducing the risk indices of the significant engine components. KEY WORDS: maintenance adjustment approach, risk analysis, risk index, lower risk criterion, upper risk criterion, significant components, ship navigation

Ljupko Šimunović, Ivan Grgurević, Jasmina Pašagić Škrinjar
2010 (Vol 22), Issue 2
Pedestrian crossings are the critical points in the traffic network that need to enable pedestrians to safely cross the road. The safety level depends on the type of pedestrian crossing. The differences between individual types of pedestrian crossings can be noted also in relation to other criteria such as the price, energy, environmental impact, accessibility, etc. Besides, various groups of users assess the quality service differently, even when this refers to the same type of pedestrian crossing. Therefore, optimal solution of a pedestrian crossing has to be selected based on a comprehensive and rational analysis and application of adequate software tools. The selection methodology of an optimal pedestrian crossing is defined using a multi-criteria analysis. In order to view the problem as a whole, four scenarios of evaluating alternatives are foreseen. Four different groups of stakeholders: traffic experts, investors, groups of persons with disabilities and healthy persons (persons not included in the previous three stakeholder groups), who use a pedestrian crossing (according to different age, disability, perception of personal safety, etc.), assessed the importance of the offered criteria. Different groups of users have different preferences in relation to individual groups of criteria, depending on their interests and needs. One group finds the criterion of pedestrian safety the most important one, others think that finances are most important (the cost of construction), some think that accessibility is the most important issue, etc. The solutions obtained in this manner provide insight into the advantages and drawbacks of individual versions. This makes it easier for the decision-makers to select only one variant / alternative from a group of the offered solutions in compliance with the defined criteria and sub-criteria with the aim of defining an optimal pedestrian crossing for a certain spatial and traffic location. KEY WORDS: pedestrian crossing, multi-criteria decision-making, analytical hierarchy process

Kostandina Veljanovska, Kristi M. Bombol, Tomaž Maher
2010 (Vol 22), Issue 2
An appropriately designed motorway access control can decrease the total travel time spent in the system up to 30% and consequently increase the merging operations safety. To date, implemented traffic responsive motorway access control systems have been of local or regulatory type and not truly adaptive in the real sense of the meaning. Hence, traffic flow can be influenced positively by numerous intelligent transportation system (ITS) techniques. In this paper a contemporary approach is presented. It considers the design philosophy of an optimal and adaptive closed-loop multiple motorway access control strategy. The methodology proposed uses the artificial intelligence technique - known as reinforcement learning (RL) with multiple agents, and applies the Q-learning algorithm. One segment of the motorway network with three lanes in each direction and three motorway entries was designed. The detectors and traffic signals were placed at the entries (ramps). Traffic flows and traffic occupancy on the main line as well as the traffic demand on the motorway entries were taken as input model variables. The output variables referred to the travel speed on the corridor, the total travel time, and the total stop time. VISSIM micro-simulator and direct programming of the simulator functions were used in order to implement the RL technique. The peak hour was chosen for the time of simulation. The model was tested in two phases. Its effectiveness was compared to ALINEA. It was observed that the proposed strategy was capable of responding both to dynamic sensory inputs from the environment and to dynamically changing environment. The model of the environment and supervision were not required. The control policy changed as response to the inherent system characteristic changes. It was confirmed that the strategy was truly adaptive and real-time responsive to the traffic demand on the corridor. KEY WORDS: motorway access, traffic flows, control, strategy, artificial intelligence, Q-Learning, simulation

Niko Jelušić, Mario Anžek, Božidar Ivanković
2010 (Vol 22), Issue 2
Advanced automatic traffic control systems and various other ITS (Intelligent Transport Systems) applications and services rely on real-time information from the traffic system. This paper presents the overview and general functions of different information sources which provide real-time information that are used or could be used in ITS. The objective is to formally define the quality of information sources suitable for ITS based on formal models of the traffic system and information sources. The definition of quality encompasses these essential factors: traffic system information that exists or may be requested, user requirements and attributes that describe the information sources. This provides the framework and guidelines for the evaluation of information sources that accounts for relevant factors that influence their selection for specific ITS applications. KEY WORDS: information source, information source quality, Intelligent Transport Systems (ITS), automatic traffic control

Robert Muha, Drago Sever
2010 (Vol 22), Issue 2
The transportation of hazardous goods represents an economic activity whose consequences can have serious impact on the safety of transportation, the environment and human health. With the aim of reviewing the elements that affect the activity, this article presents a model for the transportation of hazardous goods of which, generally, there are two forms: the theoretical model for the transportation of hazardous goods, which represents the goal for the establishment of relations on the transportation of hazardous goods services market; and the real model for the transportation of hazardous goods, which represents an adaptation of the theoretical model to the status in a specific localised region. The research, which was conducted as part of the principal author’s Ph.D. thesis, illustrates the exceptional influence of the society changes within a specific country. The theoretical model for the road transportation of hazardous goods is transposed into the real transportation services environment in Slovenia and it presents its transition and incorporation into the common EU transportation service market. KEY WORDS: transportation policy, model of the road transportation of hazardous goods

Josip Kasum, Pero Vidan, Krešimir Baljak
2010 (Vol 22), Issue 2
The density of navigation in the world waterways is considerable, especially because it is more profitable, when compared to other forms of transport. In this paper the authors propose new measures for security protection of inland waterways and of ships and ports in inland navigation. Because of various kinds of threats in inland waterways navigation it is proposed to develop the International Ship and Port facility Security Code (ISPS) code suited to such navigation. Therefore the working title of the document is proposed as International Ship and Port Facility Security Code in Inland Waterways (ISPSIW). KEY WORDS: safety, threats, protection, inland navigation

Bojan Beškovnik, Livio Jakomin
2010 (Vol 22), Issue 2
This paper describes the trends towards green logistics in global aspect and challenges of adopting green logistics in the region of Southeast Europe. Modern logistics with supply chain management is experiencing a period of important evolution. From reversible logistics, we came to green logistics, which is a wider concept of environmentally friendly thinking. Reverse logistics includes processes of movements and transportation of waste from users to recycling plants; meanwhile, green logistics deals also with environmental issues such as pollution and environmental degradation caused by improper logistics processes and utilisation of old and environmentally unfriendly transport technology. The case of Southeast Europe was analysed, and in this context, a development model for green logistics implementation was proposed. A vast number of different challenges in the logistics sector are still open in this region; therefore, systematic analyses and proposals should be subject of additional scientific work in the logistics sector. All parties, including manufacturing industry, logistics providers and governments should take an active part in such researches, as the pressure from green thinking will become even stronger in the coming period. KEY WORDS: reverse logistics, green logistics, logistics providers, Southeast Europe, green logistics model

Hrvoje Marković, Bojana Dalbelo Bašić, Hrvoje Gold, Fangyan Dong, Kaoru Hirota
2010 (Vol 22), Issue 1
A model for predicting travel times by mining spatio-temporal data acquired from vehicles equipped with Global Positioning System (GPS) receivers in urban traffic networks is presented. The proposed model, which uses k-nearest neighbour (kNN) non-parametric regression, is compared with models that use historical averages and the seasonal autoregressive integrated moving average (ARIMA) model. The main contribution is provision of a methodology for mining GPS data that involves examining areas that cannot be covered with conventional fixed sensors. The work confirms that the method that predicts traffic conditions most accurately on motorways and highways (namely seasonal ARIMA) is not optimal for travel time prediction in the context of GPS data from urban travel networks. In all the examined cases, kNN approach yields a mean absolute percentage error that is twice as good as ARIMA, while in some cases it even yields a mean absolute percentage error that is an order of magnitude better. The merit of the model is demonstrated using GPS data collected by vehicles travelling through the road network of the city of Zagreb. To evaluate the performance, the models mean absolute percentage error, mean error, and root mean square error are calculated. A non-parametric ranked Friedman ANOVA to test groups of three or more models, and the Wilcoxon matched pairs test to test significance between two models are used. The alpha levels are adjusted using the Bonferroni correction. Today’s commercial fastest-route guidance systems can readily incorporate the proposed model. Since the model yields travel times that are dependent on dynamic factors, these commercial systems can be made dynamic. Furthermore, the model can also be used to generate pre-trip information that will help users to save time. KEYWORDS: travel time prediction, urban traffic, GPS data, k-nearest neighbour, seasonal ARIMA, non-parametric regression

Rok Kamnik, Boštjan Kovačič, Andrej Štrukelj
2010 (Vol 22), Issue 1
In August 1999 an exceptional transportation of two steamers of 666 tonnes was performed from the Port of Koper to the Nuclear power plant in Krško. The transport covered a distance of about 200km and represented one of the largest exceptional transports in Slovenia ever. Finding the best route represented one of the major issues, because the steamers had to cross more than 50 problematic sections and bridges, most of which have not been designed for such heavy loads. It was necessary to load-test almost all bridges on the route to determine whether those bridges need any extra supports or not. Consequently, a logistic operator has an important and indispensable role and becomes a co-modeller of logistic service. A deformation analysis or a polynomial interpolation of vertical displacements could also be used. Therefore, a laboratory load test of a concrete plate was made. The concrete plate was loaded with hydraulic cylinder PZ 100 with extensiometer up to 21kN. Every increase of load by 3kN was measured with Nikon Ser 800 total station. KEY WORDS: deformation analysis, exceptional transport, bridges in Slovenia

Tamas Berta, Ádám Török
2010 (Vol 22), Issue 1
The main scope of this paper is to present the formulation and visualization of shortening travel time in road transport due to the improvement of road network in Hungary. The formulation of the travel time based model has been developed by the authors. The paper also presents the demonstration of the results. The approach followed is quite innovatory in terms of visualization. The travel times were taken into account as opposed to geographical distances. Also, graph theory is used in order to calculate the matrix of “travel time” distances. The data from more than 30 cities were included in the model so as to make it quite representative for Hungary. KEYWORDS: road transportation, reduction of travel time, positive external effect

Anton Hauc, Majda Bastič, Lidia Jurše, Mirko Pšunder
2010 (Vol 22), Issue 1
The construction of railway infrastructure should be dealt with as a national strategic development programme, which — due to technical, geographical, logistical, and other requirements — is carried out through a number of projects and represents a complex multiple project operation for investors, contractors, and other influential players. The national strategic development programme for the construction of railway infrastructure is connected — through programmes in the neighbouring countries and EU member states — to Trans-European networks (TEN) that strategically regulate the construction within the community. In the Republic of Slovenia, the construction of railway infrastructure within TEN programmes is carried out on the pan-European traffic Corridors V and X within individual projects for the construction of sections and a number of supporting projects. The technical requirements, deadlines, and other TEN requirements as well as national strategic requirements and financial possibilities of the state represent the basic criteria that should be taken into consideration in setting up a strategic project plan, with optimal project classification achieved through the implementation project portfolio. The current paper has utilised the method of multiple-criteria decision analysis to prepare the portfolio, taking into account the macroeconomic and infrastructural criteria. Consequently, the results represent the basis for the preparation of an optimal financial plan with regard to financing possibilities of the Republic of Slovenia and the European Union. The paper also summarises the research results regarding the formation of the project implementation process of the TEN-T network construction in the Republic of Slovenia. KEY WORDS: national strategic development, railway infrastructure construction, railway Corridors V and X, project portfolio, multiple-criteria decision analysis, Republic of Slovenia

Anita Gudelj, Maja Krčum, Elen Twrdy
2010 (Vol 22), Issue 1
The management of a container terminal is a complex process that involves many decisions. Among the problems to be solved, there are the spatial allocation of containers on the terminal yard, allocation of ships to berths and cranes, scheduling priorities and operations in order to maximize performances based on some economic indicators. Since the container port facilities are very expensive, it is desirable to optimize their performance, making better management decisions. This paper wants to present the contribution of the simulation and optimization techniques with the aim of improving the cooperation between different types of equipments, increasing the productivity of the terminal and helping in minimizing costs. In particular, the Petri net is used to present berth operations, and the genetic algorithm is used for scheduling container loading/unloading operations by cranes in order to minimize the maximum time it takes to serve a given set of vessels. KEYWORDS: transportation, berth management, scheduling, simulation, optimization

Mihaela Bukljaš Skočibušić, Natalija Jolić
2010 (Vol 22), Issue 1
From the aspect of the Republic of Croatia, short-sea shipping has multiple significance. Primarily, the short-sea shipping between the Croatian and Italian coast, diverting of a part of cargo that is transported from the European Union into the countries of south-eastern Balkan via Croatia, reduction in harmful emissions in traffic and increase of traffic in the domestic ports. From the aspect of Europe short-sea shipping refers to the movement of goods and passengers by sea between the ports located in Europe or between these ports and the ports outside Europe that have a joint sea border with Europe. The aim of introducing short-sea shipping are: relief of the burden on the European road routes and shift of transport of cargo and passengers to the maritime transport, improvement of traffic connections and competitiveness of Croatia with the European Union, as well as the connection of the Danube and the Adriatic. KEY WORDS: short-sea shipping, Republic of Croatia, maritime routes, traffic corridors

Roman Krajnc, Drago Sever
2010 (Vol 22), Issue 1
Modern approach to transportation system research is based on the system theory. System analysis is relevant. Constant transportation technique and technology devel-opment caused by the need of conformation to the new market conditions is the basis for such an approach. The model approach for resolving the problems of public pas-senger transport is provided in a scientific report. The model of quality of passenger transport comprises the submodels which define relevant measures for the provi-sion of passenger transport quality. The synthesis of sub-model for adoption of quality standards, submodel of pas-senger demands, submodel of operation safety and securi-ty and economic submodel construct the model of quality of public passenger transport (PPT). Its evaluation has been carried out using SWOT analysis. KEY WORDS: public passenger transport, traffic, lines, network, quality, mobility

Marijan Rajsman, Georg-Davor Lisicin
2010 (Vol 22), Issue 1
The objective of this paper is to analyse road traffic safety in the Republic of Croatia based on the selected indicators which were used by the legislator in bringing the Law on Road Traffic Safety which has been in force since 28 July 2004, and the achieved effects in reaching the desired safety level in the three-year period from 2005 to 2007. The aim of the research is to establish a prognostic trend of the values of the studied indicators in the time period following the enforcement of new legal regulations. Adequate safety indicator values for the respective period were analyzed using the methods of analysis and synthesis, mathematical statistics as well as trend assessment based on the found mathematical prognostic models. Based on the results of this research it was found that the basic hypothesis according to which the implementation of new legal guidelines had to result in positive change in the condition of road traffic safety, failed to be confirmed. A change in the road traffic safety improvement strategy has been proposed as well as a more significant participation and recognition of the profession and science in this field which is of great significance for the society. KEY WORDS: influence of legal regulations, road traffic safety, effects and tendencies

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