Search results for "Queue"
showing 10 items of 64 documents
Bayesian design in queues: An application to aeronautic maintenance
2007
We exploit Bayesian criteria for designing M/M/c//r queueing systems with spares. For illustration of our approach we use a real problem from aeronautic maintenance, where the numbers of repair crews and spare planes must be sufficiently large to meet the necessary operational capacity. Bayesian guarantees for this to happen can be given using predictive or posterior distributions.
Analysis of the renal transplant waiting list in the País Valencià (Spain).
2005
In this paper we analyse the renal transplant waiting list of the Pais Valencia in Spain, using Queueing theory. The customers of this queue are patients with end-stage renal failure waiting for a kidney transplant. We set up a simplified model to represent the flow of the customers through the system, and perform Bayesian inference to estimate parameters in the model. Finally, we consider several scenarios by tuning the estimations achieved and computationally simulate the behaviour of the queue under each one. The results indicate that the system could reach equilibrium at some point in the future and the model forecasts a slow decrease in the size of the waiting list in the short and mid…
A Bayesian analysis of a queueing system with unlimited service
1997
Abstract A queueing system occurs when “customers” arrive at some facility requiring a certain type of “service” provided by the “servers”. Both the arrival pattern and the service requirements are usually taken to be random. If all the servers are busy when customers arrive, they usually wait in line to get served. Queues possess a number of mathematical challenges and have been mainly approached from a probability point of view, and statistical analysis are very scarce. In this paper we present a Bayesian analysis of a Markovian queue in which customers are immediately served upon arrival, and hence no waiting lines form. Emergency and self-service facilities provide many examples. Techni…
An analytical model of a new packet marking algorithm for TCP flows
2005
In Differentiated Services networks, packets may receive a different treatment according to their Differentiateo Services Code Point (DSCP) label. As a consequence, packet marking schemes can also be devised to differentiate packets belonging to a same TCP flow, with the goal of improving the performance experienced. This paper presents an analytical model for an adaptive packet marking scheme proposed in our previous work. The model combines three specific sub-models aimed at describing (i) the TCP sources aggregate, (ii) the marker, and (iii) the network status. Preliminary simulation results show quite accurate predictions for throughput and average queue occupancy. Besides, the research…
On implicit data structures for priority queues
1985
Comparaison avec une structure liee simple et implementation de certaines structures de donnees implicites pour les files d'attente de priorite. Le minutage des experiences montre que les structures implicites sont plutot lentes
Turbo-Roundabouts: a Model to Evaluate Capacity, Delays, Queues and Level of Service
2012
A turbo roundabout is a particular type of roundabout where entering and circulating lanes are bounded by traffic signs and by non-mountable curbs. The physical separation between lanes, both at entries and on the ring, helps to prevent side collisions crossing the roundabout. The main advantages of turbo roundabouts are: i) reduction in the number of potential conflict points; ii) lower speed of vehicles passing through the intersection; iii) safety conditions at the intersection due to lower risk of side-by-side accidents. These aspects make turbo-roundabouts more appropriate than roundabouts when a higher level of safety has to be guaranteed, particularly in presence of relevant pedestri…
EVALUATING CAPACITY AND EFFICIENCY OF TURBO-ROUNDABOUTS.
2009
Recent evolution of roundabout design has been directed towards the so-called turbo-roundabout, with the aim of ensuring better safety conditions than those afforded by traditional schemes. The few turbo-roundabout installations so far implemented have not allowed sufficient research in order to analyze operational conditions and capacity models validated by field observations. In any case the theoretical approach to the functional study of turbo-roundabouts undoubtedly involves more complex aspects compared to typical roundabouts because of the paths of entering streams (constrained to get onto physically separated lanes), the “turbine” configuration of the circulatory carriageway, as well…
The M/G/1/1 queue with repeated attempts and different types of feedback effects
1985
Queueing systems with repeated attempts have wide practical use in designing switching networks and computer systems. The model presented in this paper not only takes into account repetitions by congestion but also considers the feedback effects from all types of failures in establishing a connection. A semi-regenerative analysis is applied in order to determine the characteristics of the underlying queueing process. Bedienungssysteme mit wiederholten Versuchen sind von groβem praktischen Nutzen bei der Bemessung von Vermittlungseinrichtungen und Computersystemen. Das Modell, das in dieser Arbeit vorgestellt wird, berucksichtigt nicht nur Wiederholungen nach vorangegangener Blockierung, son…
Queue Based Dynamic Charging Resource Allocation and Coordination for Heterogeneous Traffic in an Electrical Vehicle Charging Station
2021
Electric vehicle (EV) fast-charging stations (CSs) with innovative operation management strategies can help to meet the growing EV charging needs. Despite the short charging time associated with th...
Call admission control scheme using borrowable guard channels and prioritizing fresh calls retrials in small cell networks
2014
International audience; Recent trends in mobile cellular networks turn towards deployment of Small Cell Networks (SCNs), where, the cell size gets smaller, and thus the number of subscribers served in a cell will be relatively smaller, such that traffic models with a finite source of subscribers should be considered. Smaller cells cause the mobile subscribers to cross several cells during an ongoing conversation resulting in frequent handovers. Most of works dealing with Call Admission Control (CAC) problems based on guard channels scheme in cellular mobile networks consider models without retrials (reapeted calls phenomenon). However, almost all existing works which take into account retri…