98 research outputs found
Road traffic Modelling and Simulating with fluid-dynamic approach
No full textIn this work we present a mathematical model for fluid-dynamic flows on road networks, based on conservation laws according with Piccoli et al. approach. The road network is represented by means of a links and nodes structure. A description of Riemann Solver at junction is given and a complete implementation of this model is then presented, together with some results from computational experiences on different real case studies of road networks
Exponential queuing system with negative customers and bunker for ousted customers
No full textConsideration was given to the queuing system with Poisson flows of incoming positive
and negative customers. For the positive customers, there is an infinite-capacity buffer.
The arriving negative customer knocks out a positive customer queued in the buffer and moves
it to an infinite-capacity buffer of ousted customers (bunker). If the buffer is empty, then the
negative customer discharges the system without affecting it. After servicing the current customer,
the server receives a customer from the buffer or, if the buffer is empty, the bunker.
The customers arriving from both the buffer and bunker are distributed exponentially with the
same parameter. Relations for calculation of the stationary distributions of the queues in the
buffer and bunker were obtained
Modelling emergencies with a priority stochastic system
No full textThe aim of this work is to analyze the Italian emergency system, particularly the Italian radio communication system 118 for the region Campania, and to investigate the effects of the management of different users having different gravity codes for the required services.
The real system under consideration can be modelled with a tandem queueing network. The first node describes the calls of users, and can be seen as an exponential queueing system.
The second node describes the assistance means communication apparatus with the headquarters of 118 and, in the actual real system, works in such way that it can be modeled as a M/M/c/infinity queue, where c are the couple of frequencies. We propose a radio communication system modelled as a M4/M4/c/infinity queueing system with priority service discipline. For the computation of analytical results, we reduce the number of gravity codes, modeling the second node with a M2/M/c/infinity queueing system with priorities
A Virtual Scientific Experiment To Understand Self-Similarity
No full textThe aim of this work is to investigate the effect on learning performance of the use of Virtual Scientific Experiments,
realized using a learning model able to support and improve the e-learning environment IWT. The models consists in
different implication phases: Active Situation, Collaborative Learning, Assessment, Addressed Situation, Knowledge
Institutionalization. In particular a Virtual Scientific Experiment for Self-Similar Processes has been realized to highlight
the singular nature of multimedial traffic compared with the telephonic one
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