Vol. 16 No. 6 (2004)
Slavko Šarić, Jozo Balić, Rudo Vidović
2004 (Vol 16), Issue 6
This article presents a review of the existing networks andthe NGN concept. By analysing the condition of the existingtelecommunication networks and services it is obvious that theyare different single-se1vice networks that cannot meet the requirementsof the users for various se1vices. The increased demandsof the users for telecommunication se1vices have inducedthe introduction of liberalization in the telecommunicationmarket. That opened the door for competition and greatinvestments in the development of telecommunication networks.The existing telecommunication networks orientated to thetransmission of voice and the existing data network could notbe adapted to new requirements without difficulties. That is thereason why the search for a solution for convergence and unionof a great number of different single-service networks started.The basic requirement was reduced in the end to the conceptionof the universal wideband data network that can meet all thedemands of the users by dividing the resources. As a collSequenceof that it was necessmy to find the solution for the transmissionof voice by a data network. The solution was seen in theerection of softswitch architecture for VoiP. Thus, the voicewould be transmitted by packets as one of the components indata transmission. It was necessary to define protocols for enablingthe operation in the NGN conception, as well as to thoroughlyobserve the problems of the JP telephony operation in regardto the real-time voice component. Apart from these tasks itwas necessmy to see how to adapt the existing networks into theNGN conception and to provide interaction between differentnetworks and different layers of networks by applying certainstandards and protocols. The awareness of the necessity ofgradual introduction and realization of NGN conception hasbecome obvious, always in the relation to the existing conditionof PSTN and the users' demands. Special attention should begiven to the introduction of IN as a tool for the realization ofadditional se1vices and for enabling the control in NGN. Theproblem of JP routers for NGN has also been mentioned, aswell as the importance of the new core generation of optical networks.The conceptual framework of NGN is based today onIP/ATM transport technology, which is at this level of developmentgenerally accepted as the optimal transp011 solution. The problem of addressing caused by the insufficient address spaceof Ipv4 has been stressed and the solution of that problem hasbeen anticipated with the introduction of lpv6 technology,which, due to its complexity and high costs, would be graduallyintroduced by a dual approach into the system.The differentiating elements of NGN in relation to the existingnetworks have been specially pointed out. The modulm;that is, plane nature of the NGN conception in relation to thevertical and hierarchical conception of PSTN has beenstressed, as well as the pdvileges that this open conception offerswhen choosing the equipment of the highest quality by differentmanufacturers. Both existing, voice (TDM) and data(NGN) (ATM/IP), networks will act parallel in the next yearsuntil new solutions to NGN will have been introduced.
Iztok Ostan
2004 (Vol 16), Issue 6
The empirical sociological studies of exploitation are nowadaysrare in Slovenia and in other countries as well. Researchamong Slovene students showed that according to their statementsthere is much exploitation in Slovenia and that it hasbeen increasing. It showed also that statements of students donot differ much from the results of public opinion research regardingexploitation, nor from the statements of irregular studentswith long working experience. It was also found that thereare no substantial differences in statements of Italian and Slovenestudents. Traffic technology students are a group amongfull-time students who agree most with the statements that thereis much exploitation and that it has been increasing. A hypothesiswas set that statements of these students could be used as anindicator of general student opinion regarding exploitation.
Mirsad Kulović
2004 (Vol 16), Issue 6
The road freight transport costs are a function of numerousfactors that could be grouped according to their characteristicsand level of utilization of company's technical and human potential.The different input prices, product characte1istics, truckconfiguration, geographical characteristics, road conditions,and driving characteristics make it very difficult to estimate thecurrent transportation costs for a particular company. To investigatethe main factors that may affect road freight transportcosts, it is useful to analyze the influence of truck fleet operationalparameters on these costs. This paper desc1ibes freighttransport costs model based on tntck fleet operational parameters.The explanation of the model is given through a practicalexample. The model enables changes of input parameters andreflects the influence of different management decisions whichhave an impact on transportation costs.
Andrej Godec, Boštjan Hernavs
2004 (Vol 16), Issue 6
Over the past few years we have been witnessing a rapid andundreamt of development in the communications field. Every·one wants to communicate with others all the time. Industry isa major generator of these changes. But users do not like fastand frequent changes because they usually mean nothing good.The majority is satisfied with basic necessities and there is ahuge problem in t1ying to convince them into something new.There is a difference between technical and marketing sector.We are dealing with economy, promises, contracts. But industrywants more: new users, fresh money for new investments.The aim of this article is to find a technical solution for increasingthe existent optical cable capacities. The purpose is notto replace the existing cables but to use advanced technologyand to improve economy, safety and reliability of all kinds ofcommunications which use optical transmission medium.
Slavko Šarić, Anto Bilobrk, Davor Nađ
2004 (Vol 16), Issue 6
Voice transmission over JP networks (Voice over InternetProtocol) represents one of the ways in which voice and datanetworks are integrated. The future development is based onthe explosion of the Internet as the means of communication,with the openness of standards and the readiness of the equipmentmanufacturers to accept such standard and to unify it.The service providers find interest in introducing new servicesthat are not based only on voice transmission, but voice becomesonly one of the applications that are realised over the JPnetworks. Voice transmission over the JP technology is at themoment not at the level of the existing quality of services, butthe coming solutions in the near future will enable Vo!P as thestandard operative solution. The advantages are reflected in theincrease of income keeping the current users and attracting newones, investments into infrastructure will maximize the opportunitiesfor packet service development, strengthen customers'loyalty and reduce operative expenditures, the services will bewidespread - long-distance international services or nationalservices of calling cards can be located at almost any European,African, or Central-Eastern count1y and directed to almost100 percent of the population. With the advantages of lowinitial costs of the new POPs (Points of Presence), the serviceproviders can suddenly expand their presence to many countriesor destinations.
Goran Zovak, Goran Beraković, Ivica Ostrun
2004 (Vol 16), Issue 6
Traffic accidents in road traffic are becoming an increasingproblem regardless of whether there is only material damage orserious injuries and fatalities. There are various causes resultingin traffic accidents, and this paper describes the reconstructionwork on a section of the motorway in order to improve thetraffic safety. Also, the results of the given reconstruction havebeen analysed.
Velimir Kolar, Vinko Jenić, Boris Magličić
2004 (Vol 16), Issue 6
The paper deals with all the resources and factors that determineor influence to any extent the technological process ofstaff of train rostering. The Timetable, Train Traction andTraction Vehicle Maintenance Sector and the legal regulationsstipulate the basic parameters for rostering and these are explained.The paper also analyses the contents and the methodof producing the rostering plan which shows all the practicaldrawbacks and the limiting factors that influence significantlythe possibility of corrections in order to improve the utilisationlevel of the staff of train. A model has been developed with thepresentation of the factors that influence the staff of train rostering.The paper also shows the project of a software solutionfor the staff of train rostering with the defined and explainedClipper program.
