Oana Dinu

Maritime vessel obsolescence, life cycle cost and design service life

Maritime vessels have long service life and great costs of building, manning, operating, maintaining and repairing throughout their life. Major actions are needed to repair, renovate, sometime built or even replace those scrapped when technology or demand changes determine obsolescence. It is regarded as a concern throughout vessels entire life cycle and reflects changes in expectation regarding performances in functioning, safety and environmental effects. While service live may differ from physical lives, expectations about physical lives is the main factors that determines design service life. Performance and failure are illustrated conceptually and represented in a simplified form considering the evolution of vessels parameters during its service life. In the proposed methodology an accumulated vessel lifecycle cost is analyzed and obsolescence is characterized from ships design, performances, maintenance and management parameters point of view. Romanian ports feeding Black Sea are investigated in order to provide comprehensive information on: number and types of vessels, transport capacity and life cycle length. Recommendations are to be made in order to insure a best practice in lifecycle management in order to reduce costs.

Development of Non-Motorized Infrastructure Network in Oradea City Using Dijkstra Algorithm in ArcGIS

In this paper it is developed a location model for the infrastructures dedicated to non-motorized movements by bike in Oradea city, using ArcGIS geographic and information system [3]. They are taken into consideration the movements made by the target people – alternating movements (from home to school) and optional movements (made for recreation), the densities in residential areas, the type of the city arteries and the mobility need of the target people (in this case – young people aged between 15 and 25) in order to design two structures of the transport infrastructure networks (one for the alternating movements and the other for the optional movements), structures which will be realized on the actual frame of the existing transport infrastructure in Oradea city. Using Dijkstra algorithm, the minimal routes for the movements related to the alternating mobility, but also for the movements specific to the optional mobility are determined. Further on the most used arteries in the two structures of urban infrastructure networks are determined. The paper suggests as a solution the structure of the network for the non-motorized movements and also those arteries that must be used for its development, that guarantee gains for the target people (time), for the main operators who exploit the motorized systems, for the local budget of the local municipalities (less funds to sustain the public services) and especially for the environment and people’s health (attenuation of noxious and phonic pollution, reduction of the accidents’ number and health improvement).

Planned Traffic Stability on a Rail Network

Impetuous multiplication of mobility and road traffic proliferation lead to concerns for increasing the attractiveness of urban public transport. Compared to private car use, urban public transport attractiveness is conditioned, in particular, by travel times and certainty of respecting the transport schedules, meaning planned traffic stability. Traffic schedules are considered to be more stable as the primary delays from the announced schedule have low probabilities and values and their propagation as repeated delays is least noticed in time and space. Solutions for assuring traffic stability must take into consideration contradictory aspects, because introducing time reserves in the schedules means time travel extensions. In order to assure the stability of planned traffic, present paper develops studies of various models and methods that aim to reduce inherent primary delays. Thereby, for studying repeated delays on a complex network, a mathematical model adequate to a Discrete Event Dynamic System (DEDS), that in MAX-PLUS algebra becomes a linear system, was used. The paper concludes with a case study on an integrated network resulted from the superposition of Bucharest’s existing suburban rail network with the underground network designed for 2030, being identified measures for improving the stability indicators. Traffic stability is assessed on the basis of two indicators: instability coefficient and delay elimination rate. Main measure for improving stability indicators is the growth of time reserves taking into consideration the quality requirements resulting from the condition of maintaining a reduced planned travel time.

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.