Computer simulation for the evaluation of static and dynamic priority schemes in an ATM multiplexer with multimedia traffic

1999 ◽  
Vol 9 (6) ◽  
pp. 359-369
Author(s):  
Saud Al-Barrak ◽  
Adnan Nouh ◽  
Saad Haj Bakry
Keyword(s):  
Computer Simulation ◽  
Multimedia Traffic ◽  
Dynamic Priority ◽  
Atm Multiplexer ◽  
Priority Schemes

DELAY ANALYSIS OF A MULTIMEDIA ATM MULTIPLEXER WITH HOMOGENEOUS ARRIVALS

2004 ◽  
Vol 13 (05) ◽  
pp. 999-1018 ◽  
Author(s):  
HAMED NASSAR ◽  
HASAN AL MAHDI
Keyword(s):  
Random Variable ◽  
Delay Analysis ◽  
Multimedia Traffic ◽  
Batch Arrivals ◽  
File Transfers ◽  
Class 1 ◽  
Atm Multiplexer ◽  
Time Class ◽  
Special Case ◽  
General Size

In this paper we present a delay analysis of an ATM multiplexer handling multimedia traffic of two classes: real time class, e.g., live audio and video and nonreal time class, e.g., file transfers. Packets arrive into the multiplexer in batches of general size and are output one at a time. The arrivals are homogeneous in the sense that either the arriving batch is all class-1 packets or all class-2 packets. The multiplexer is modeled as a priority discrete time queueing system with batch arrivals and geometric service. The homogeneity of the arrivals is reflected by the addition of an indicator random variable into the model. The analysis is comprehensive in that it covers the three main delay measures: the unfinished work, the busy period and the waiting time. For these measures, probability generating functions are derived, from which moments of arbitrary orders can be obtained. However, only the first moments are obtained in the article to produce expected values. Presented at the end is a special case when the arriving batches are of Poissonian size. Some numerical values are obtained and plotted for this case.

scholarly journals Impacts of Metering-Based Dynamic Priority Schemes

2021 ◽  
Author(s):  
Raphaël Lamotte ◽  
André de Palma ◽  
Nikolas Geroliminis
Keyword(s):  
Arrival Time ◽  
Cost Savings ◽  
Pareto Improvement ◽  
Modal Shift ◽  
Dynamic Priority ◽  
Schedule Flexibility ◽  
Set Up ◽  
Priority Schemes ◽  
Pareto Improving ◽  
Small Capacity

Several works published over the last two decades have shown for a stylized set-up with homogeneous users that metering-based priority (MBP) schemes may generate Pareto improving departure time adjustments similar to those induced by congestion pricing, but without any financial transaction. We investigate whether MBP (i) still generates significant savings and (ii) remains Pareto-improving, with various sources of heterogeneity (in schedule flexibility, desired arrival time, and capacity usage). We consider two types of schemes: one where the priority status is allocated randomly (R-MBP) and another (HOV-MBP), which only prioritizes users with small capacity usage (e.g., carpoolers). We find that the relative total cost savings of R-MBP decrease with heterogeneity in flexibility, but may increase with heterogeneity in desired arrival time. It fails however to be Pareto-improving, as nonprioritized users are almost systematically worse-off. HOV-MBP circumvents this issue by generating an ordering effect and a modal shift, which both contribute to a better distribution of benefits among users. Under favorable circumstances, they may even restore a Pareto improvement. Overall, MBP appears as a realistic way to alleviate congestion, scoring well both in terms of efficiency and social acceptability.

Characterization of Modulated Structure Through Structure Images and their Computer Simulation

1990 ◽  
Vol 48 (1) ◽  
pp. 70-71
Author(s):  
Kiyomichi Nakai ◽  
Yusuke Isobe ◽  
Chiken Kinoshita ◽  
Kazutoshi Shinohara
Keyword(s):  
Computer Simulation ◽  
High Resolution ◽  
Spherical Aberration ◽  
High Resolution Electron Microscopy ◽  
Basic Mechanism ◽  
Objective Lens ◽  
Specimen Thickness ◽  
Transmitted Beam ◽  
Modulated Structure ◽  
Resolution Electron

Induced spinodal decomposition under electron irradiation in a Ni-Au alloy has been investigated with respect to its basic mechanism and confirmed to be caused by the relaxation of coherent strain associated with modulated structure. Modulation of white-dots on structure images of modulated structure due to high-resolution electron microscopy is reduced with irradiation. In this paper the atom arrangement of the modulated structure is confirmed with computer simulation on the structure images, and the relaxation of the coherent strain is concluded to be due to the reduction of phase-modulation.Structure images of three-dimensional modulated structure along <100> were taken with the JEM-4000EX high-resolution electron microscope at the HVEM Laboratory, Kyushu University. The transmitted beam and four 200 reflections with their satellites from the modulated structure in an fee Ni-30.0at%Au alloy under illumination of 400keV electrons were used for the structure images under a condition of the spherical aberration constant of the objective lens, Cs = 1mm, the divergence of the beam, α = 3 × 10-4 rad, underfocus, Δf ≃ -50nm and specimen thickness, t ≃ 15nm. The CIHRTEM code was used for the simulation of the structure image.

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