Mircea Rosca

Transshipment Modeling and Simulation of Container Port Terminals

The growth of containerization and transporting goods in containers has generated capacity and equipment allocation problems in maritime ports. Container terminals represent complex systems with dynamic interactions between the various handling, transportation and storage units, and uncertainties about future events. Maritime container terminal operates at full capacity if the arrival of vessels to berth is uniform according to its capacity and equipment operating at constant parameters. Since there are random factors both on the arrival of ships and on the operation of equipments, the paper analyzes the influence of these factors on the terminal capacity. Therefore, we proposed a generic simulation model structure for the comparative assessment of the measures of performance of maritime terminal in ideal conditions (without perturbations in the terminal operation) and in different statistical assumptions of vessels inflows to berth and number of containers to unload per vessel. Based on event driven and virtual reality technology, the handling technology simulation model is developed using ARENA simulation software. The model is set-up by combining three basic functions: transport, transfer, and stacking. The transport activity is assumed by the flows of the container vessels and trucks. Different characteristics of the arrival flows are assumed (intervals between transport units, number of containers to unload). Quay cranes provide the container transfer. The stacking areas consist in one capacity area on the quay for the quick transfer on trucks. The simulation results lead to the conclusion that it can be achieved berth high occupancy and minimization of vessels waiting time at the port if the vessels inflows follow a distribution with small variance around the ideal value.

Simulation model for port shunting yards

Sea ports are important nodes in the supply chain, joining two high capacity transport modes: rail and maritime transport. The huge cargo flows transiting port requires high capacity construction and installation such as berths, large capacity cranes, respectively shunting yards. However, the port shunting yards specificity raises several problems such as: limited access since these are terminus stations for rail network, the in-output of large transit flows of cargo relatively to the scarcity of the departure/arrival of a ship, as well as limited land availability for implementing solutions to serve these flows. It is necessary to identify technological solutions that lead to an answer to these problems. The paper proposed a simulation model developed with ARENA computer simulation software suitable for shunting yards which serve sea ports with access to the rail network. Are investigates the principal aspects of shunting yards and adequate measures to increase their transit capacity. The operation capacity for shunting yards sub-system is assessed taking in consideration the required operating standards and the measure of performance (e.g. waiting time for freight wagons, number of railway line in station, storage area, etc.) of the railway station are computed. The conclusion and results, drawn from simulation, help transports and logistics specialists to test the proposals for improving the port management.

The influence of transport network vulnerability for maritime ports

The concepts of reliability and vulnerability are quite important in assessing the ability of transport networks from land to provide continuity in operation tacking in consideration the relation with seaports. Transport infrastructure modernizing and extension according to land use and sustainable development requirements still represents a challenging issue among policy makers, regional/local communities and scientists. The interest for the researches reliability and vulnerability for transport networks who connect maritime ports with interior citys is generate by the natural disasters, the terrorist acts, unconventional war, etc.. Transport network modelling enable the development of mathematical models used in evaluating the reliability and vulnerability. Nodes or link disruption could have an important impact over transport network users. In our paper we investigates the Romanian road network vulnerability related to Danube crossing versus maritime ports (Constanta and Mangalia) and its mitigation by improving network topology. We use Visum software to promote a methodology to assess road transport network vulnerability versus Romanian seaports and we propose some solutions to reduce probability of road transport network to fail.

Traffic Modeling in Urban Congested Areas

The paper aims to identify solutions for traffic safety enhancement in an urban area where major changes in traffic flow intensity and pattern will occur. The changes of the study area pattern will be caused, on the one hand, by the development of new residential and office areas and, on the other hand, by the opening of a new road overpass linking the inner urban area with an outside area where peri- and regional traffic flow are concentrated. The assessment of the traffic systematization solutions under these new conditions is based on a simulation model developed with the AIMSUN software. The study area is located in Bucharest, around the zone of University Politehnica of Bucharest Campus. The main difficulty of the model consists in the prediction of the exogenous traffic data of the study area. The simulation model is applied for one proposed scenario considering the increase of the traffic flow intensities. A set of measures for traffic systematization is assessed and compared based on flow features (speed, frequency and time of stops, external effects limitations).

ROAD ACCIDENT ESTIMATION MODEL IN URBAN AREAS

Summary. Urban areas are significantly different in terms of traffic risk. In a decisive manner, they are the result of...

Inland waterway ports nodal attraction indices relevant in development strategies on regional level

Present paper aims to propose a set of ranking indices and related criteria, concerning mainly spatial analysis, for the inland waterway port, with special view on inland ports of Danube. Commonly, the attraction potential of a certain transport node is assessed by its spatial accessibility indices considering both spatial features of the location provided by the networks that connect into that node and its economic potential defining the level of traffic flows depending on the economic centers of its hinterland. Paper starts with a overview of the critical needs that are required for potential sites to become inland waterway ports and presents nodal functions that coexist at different levels, leading to a port hierarchy from the points of view of: capacity, connection to hinterland, traffic structure and volume. After a brief review of the key inland waterway port ranking criterion, a selection of nodal attraction measures is made. Particular considerations for the Danube inland port case follows proposed methodology concerning indices of performance for network scale and centrality. As expected, the shorter the distance from an inland port to the nearest access point the greater accessibility. Major differences in ranking, dependent on selected criterion, were registered.

The Optimal Allocation of Unloading/Loading Ramps in Distribution Centers

Warehousing enables the consolidation of shipments to clients by assembling full truck loads from goods stored in warehouse or distribution center. Storage can be efficiently replenished by ordering full truck loads from suppliers. In order to reduce freight storage and handling costs from distribution centers, cross-docking technique represents a logistic solution which is more and more used. Thus, the optimization of simultaneous unloading/loading operations constitutes an important issue for the distribution center owner/administrator. This paper presents a model based on genetic algorithms optimization techniques for solving the problem of unloading/loading ramps allocation. The efficiency of a cross-docking center is conditioned practically by finding an allocation and an optimal arrangement of ramps. This implies the allocation of destinations to unloading/loading ramps of distribution centers to minimize the total distance performed by the the cargo handling equipment. The case study presents a cross-docking platform with single handling equipment which is assigned to 10 unloading/loading ramps. By applying the solution of the ramp allocation generated through simulation, the total distance performed by the handling equipment is reduced which means lower handling cost for the distribution center owner/administrator.