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A container terminal can be defined as a mass service system in which a multiphase service processes takes place. The terminal consists of three subsystems: quayside, yard and gate. In this paper, queuing theory as one of the operational research method is been used, to determine indicators of functioning the service system on the example of the container terminal of the port of Rijeka. Applying the queueing theory, the service phases that represent a bottleneck can be determined, as well as the phases in which the largest capacity surpluses are located. Finally, based on the current capacities the optimal turnover of the terminal was provided, without congestions and with the highest degree of terminal utilization. The basic conclusion is that the capacity of the system is limited by the capacity of the subsystem that has the smallest capacity, and in this case it is gate/truck and train operation area.

Svaki veliki sustav trebao bi prepoznati i znati upravljati svojim rizicima. Problem istraživanja u ovom radu su kvarovi na kontejnerskim dizalicama, jer je za obalne dizalice u procesu prekrcaja na kontejnerskom terminalu izuzetno važno prepoznati kritične kvarove i pridati im pozornost prilikom redovnog odnosno preventivnog održavanja. Da bi se operativni proces prekrcaja na terminalu odvijao bez zastoja uz osiguranje sigurnosti osoblja te na vrijeme prepoznali kvarovi koji predstavljaju najveći rizik može poslužiti metoda analize oblika i efekata kvarova, koja je odabrana za rješenje problema procjene rizika u ovom radu. Provedeno je anketno ispitivanje osoba koji rade na kontejnerskom terminalu riječke luke o vrsti i učestalosti pojedinih kvarova na obalnim dizalicama. Potom je za svaki kvar ocijenjena razina ozbiljnosti, učestalosti i otkrivanja, na temelju čega su izračunom veličine prioriteta rizika isti rangirani. Dobiveni rezultati ukazuju da najveći rizik ima fizičko oštećenje sajli dok je najmanji rizik predstavljaju neispravne nauglice kontejnera. Ovakav način istraživanja može doprinijeti budućem pravovremenom planiranju održavanja i preventivnog otklanjanja kvarova u svrhu neometanog odvijanja prekrcajnog procesa., Every large system should recognize and know how to manage its risks. The research problem in this paper is failures on container cranes, since it is extremely important, for quay cranes in the process of transhipment at the container terminal, to recognize critical failures and pay attention to them during regular or preventive maintenance. In order that the operational transhipment process at the terminal run efficiently, while ensuring the safety of staff and to identify failures that pose the greatest risk in a timely manner, the method of analyzing the forms and effects of failures can be used. This method is recognized as appropriate for solving the problem of risk assessment in this paper and also contributes to their controlling. A survey of operators working at the container terminal of the Port of Rijeka was conducted, on the type and frequency of individual failures on shore cranes. The level of severity, frequency and detection was then assessed for each failure, on the basis of which they were ranked by calculating the size of the risk priorities. This method of research can contribute to the future timely planning of maintenance and preventive troubleshooting for the purpose of uninterrupted transhipment process.

The major cause of under-capacity or overcapacity at smaller airports is seasonality. Such airports are finding it difficult to determine the capacity to meet the demand and adequately handle passengers in both high and low season. If the capacity is not optimally defined, excessive congestions and waiting times occur, resulting in lower service quality. Airports greatly benefit from capacity utilization analysis in terms of more accurate planning, designing, and adjusting capacity to the current demand in order to encourage further development as well as to reduce additional costs. Using queuing theory, this paper aims to answer the following question: is the passenger capacity at Rijeka International Airport (Croatia) optimally determined to meet the demand promptly, both in high and low season, without causing excessive congestions and waiting times. The results obtained indicate the occurrence of overcapacity since high season demand can be well served, even with reduced capacity used in the low season when demand is significantly lower.

Glavni cilj modeliranja prometnog sustava je uspješno poslovanje i kontinuirano istraživanje mogućnosti za njegovo poboljšanje. Primjenom modela predloženog u ovom radu mogu se dobiti korisni rezultati potrebni za uspješno upravljanje lučkim sustavom. Ovi bi rezultati trebali usmjeriti menadžere u luci na donošenje odgovarajućih odluka u cilju poboljšanja poslovne efikasnosti i povećanja konkurentnosti luke. Model se temelji na teoriji općih sustava. Lučki sustav može se predstaviti kao fizički sustav koji tijekom vremena mijenja stanja na slučajan način, tj. prelazi iz jednog stanja u drugo pod utjecajem slučajnih čimbenika koji se ne mogu unaprijed predvidjeti. Ovdje je sustav "usluživanje broda na pristanu" definiran sa skupom elemenata i veza između njih, odnosno UC-strukturom. Nadalje, identificirana su stanja i prijelazi između stanja, zajedno sa shemom ST-dijagrama. Na temelju ST-dijagrama, postavljen je sustav diferencijalnih jednadžbi i preporučen računalni program za njihovo rješavanje., The main goal of the traffic system modelling is successful running a business and continuously searching the possibilities for its improvement. With the application of the model set in this paper one can get the valuable results for managing the port system. These results should route the port managers to bring appropriate decisions in order to enhance the business efficiency and enlarge the port competitiveness. The model presented is based on the general systems theory. The port system can be presented as a physical system which over time changes its status to a random manner i.e., exceed from one state to another under the influence of random factors that cannot be predicted in advance. Here, the system "serving ship at quay" is defined with the universe of discourse and couplings (UC-structure), dividing it on elements and links between them. Next, the states and the transitions between the states are identified, along with the scheme (ST-diagram). From the ST-diagram the system of differential equations is set and the computer program for solving is recommended.

The paper demonstrates the application of the queuing theOIYin modelling the port's bulk cargo unloading terminal. Abulk cargo terminal can be obsetved as a queuing system definedby basic parameters: the rate of bulk cargo ship arrivals orquantity of bulk cargo and the rate of ship servicing i. e. quantityof bulk cwgo, in an observed time unit. Appropriate indices ofbulk cmgo terminal operations are computed on the basis ofthese parameters. The unloading terminal is detennined as aqueuing system marked with MIMI I by Kendall notation. Thesystem is characterized by Poisson distribution of entity arrivalsand exponentially distributed service time. Subsequently, themodel set up will be tested on the real example of the unloadingterminal of the bulk cmgo port in Bakar. Through applicationof the proposed model it should be possible to make a decisionon how to optimize the transhipment processes on the bulk dischmgingtemzinal to increase its efficiency. The obtained parametersand the calculated indices point to solid capacity employmentrate in 2005 and the probability that the berth is unoccupiedis relatively low. Indices show that the tenninaltrafficrate has dramatically improved taking into consideration theprevious years.

This paper focuses on a bulk terminal short term operations planning problem faced by the port management in tactical decision making. Loading and discharging of ship cargo, cargo stocking, maintenance and service of facility equipment are regular operations of a sea port's bulk terminal. Their organization is subject to difficult-to-predict or unforeseen influences. The challenge that port management faces in day to day operations is in making the best possible plan with scheduled duration of operations/states and transition instants, considering various internal and external factors influencing terminal performance. A states and transitions model is used to derive effective solutions for obtaining states order and states transition time of a bulk terminal, with the objective of minimizing operational costs. Behavior of the terminal is tested with stochastic and deterministic methods.

Za uspješno poslovanje prometnog sustava neophodno je kvalitetno upravljanje. U tu svrhu treba proučiti čimbenike koji utječu na uspješnost poslovanja te istražiti pokazatelje uspješnosti poslovanja i načine za njihovo poboljšanje. Da bi se s prometnim sustavom moglo uspješno upravljati treba postaviti odgovarajući model/modele koji će predstavljati njegovu pojednostavljenu sliku. Cilj rada je istraživanje mogućih problema i poteškoća koje se javljaju pri modeliranju prometnog sustava, te nalaženje rješenja ili mogućnosti za njihovo izbjegavanje. Radi lakšeg i razumljivijeg tumačenja u radu je za ilustraciju odabran primjer lučkog sustava, a navedeni rezultati istraživanja mogu se vrlo lako prepoznati i primijeniti pri modeliranju drugih prometnih sustava., A high-quality management is essential for a successful business of the traffic system. Therefore, the factors affecting on business performance need to be researched, as well as business efficacy indicators and the ways for their improvement need to be explored. In order to manage the traffic system successfully, the setting up of the appropriate model/models representing a simplified real traffic system is required. The aim of this paper is to research into possible problems and difficulties that occur when modelling the traffic system and to find solutions or options for their avoidance. For a better and easier interpretation of the research work done, the example of the port system is selected for illustration. The listed research results can be very easily identified and applied in modelling other traffic systems.

U ovom radu istražuje se utjecaj rezultata problema dodjele veza ovisno o različitim varijantama projekta riječne luke. Uspoređujući postavu višenamjenskih i specijaliziranih vezova na temelju optimalnog pridruživanja vezova plovilima, sa zahtjevima u pogledu efikasnosti luke, moguće je odabrati najbolju varijantu projekta. Cilj je postići optimalni raspored plovila uzduž pristana uz minimalno zadržavanje plovila u luci i minimalni utrošak prekrcajnih resursa. Model osmišljen u ovom radu testiran je na primjeru luke unutarnjih voda. Za rješavanje problema korištena je metoda linearnog programiranja u sklopu koje je posebno razrađen i prilagođen problem asignacije na takav način da se dobiju praktični rezultati u što manje matematičkih iteracija uz prihvatljivu točnost rezultata., This paper explores the impact of berth allocation problem (BAP) solving depending on different options for river port design. Comparing multipurpose and specialized berths layout with port efficiency requirements, based on berth allocation, an optimal design option may be selected. The aim is to achieve an optimal distribution of vessels alongside quay with minimum vessels' time in port and port operator workload. The model set up in this paper is tested on the example of the inland waterway port. The problem solution is attained using the linear mixed integer programming method. Standard assignment problem is adjusted in such a way to achieve the practical results in as low as possible mathematical iterations while not compromising results' precision.