scholarly journals Diffusion Model of Preemptive-Resume Priority Systems and Its Application to Performance Evaluation of SDN Switches

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5042
Author(s):  
Tomasz Nycz ◽  
Tadeusz Czachórski ◽  
Monika Nycz
Keyword(s):  
Diffusion Approximation ◽  
Numerical Models ◽  
Software Defined Networks ◽  
Detailed Model ◽  
Preemptive Resume ◽  
Central Controller ◽  
Priority Systems ◽  
Primary Element ◽  
Preemptive Resume Priority ◽  
General Distributions

The increasing use of Software-Defined Networks brings the need for their performance analysis and detailed analytical and numerical models of them. The primary element of such research is a model of a SDN switch. This model should take into account non-Poisson traffic and general distributions of service times. Because of frequent changes in SDN flows, it should also analyze transient states of the queues. The method of diffusion approximation can meet these requirements. We present here a diffusion approximation of priority queues and apply it to build a more detailed model of SDN switch where packets returned by the central controller have higher priority than other packets.

Preemptive resume priority retrial queue with two classes of MAP arrivals

2013 ◽  
Vol 7 ◽  
pp. 2569-2589 ◽  
Author(s):  
M. Senthil Kumar ◽  
S. R. Chakravarthy ◽  
R. Arumuganathan
Keyword(s):  
Retrial Queue ◽  
Preemptive Resume ◽  
Preemptive Resume Priority

AVAILABILITY AND COST ANALYSIS OF A PARALLEL REDUNDANT COMPLEX SYSTEM WITH TWO TYPES OF FAILURE UNDER PREEMPTIVE-RESUME REPAIR DISCIPLINE USING GUMBEL-HOUGAARD FAMILY COPULA IN REPAIR

2008 ◽  
Vol 15 (04) ◽  
pp. 341-365 ◽  
Author(s):  
MANGEY RAM ◽  
S. B. SINGH
Keyword(s):  
Complex System ◽  
Cost Analysis ◽  
Time To Failure ◽  
Preemptive Resume ◽  
Special Cases ◽  
In Series ◽  
State Behaviour ◽  
General Distributions ◽  
Mean Time ◽  
Steady State Behaviour

This paper discusses about the availability of a complex system, which consists of two independent repairable subsystems A and B in (1-out-of-2: F) and (1-out-of-n: F) arrangement respectively. Subsystem A has two identical units arranged in parallel redundancy (1-out-of-2: G), subsystem B has n unit in series (1-out-of-n: F) with two types of failure, viz., partial and catastrophic. Except at two transitions where two types of repair namely exponential and general possible all other transitions have single possibility between any two states. The failure and repair time for both subsystems follow exponential and general distributions respectively. The model is analyzed under "preemptive-resume repair discipline" where A is considered to be in priority while B is non-priority. By employing supplementary variable technique, Laplace transformation and Gumbel-Hougaard family copula various transition state probabilities, availability, Mean Time to Failure (MTTF) and cost analysis (expected profit) are obtained along with steady-state behaviour of the system. Inversions have also been carried out so as to obtain time dependent probabilities, which determine availability of the system at any instant. At last some special cases of the system have been taken.

On the work load process in a general preemptive resume priority queue

1972 ◽  
Vol 9 (03) ◽  
pp. 588-603 ◽  
Author(s):  
R. Schassberger
Keyword(s):  
Distribution Function ◽  
Work Load ◽  
Priority Queue ◽  
General Distribution ◽  
Time Service ◽  
Service Unit ◽  
System A ◽  
Preemptive Resume ◽  
Preemptive Resume Priority ◽  
Method Of Phases

Consider the following queuing system: A sequence of customers arrive at a service unit in a recurrent stream. A customer is of priority k with probability πk , k = 1, …, n. A class i customer preempts service of class k, k > i. Interrupted service is resumed without loss or gain in service time. Service is FIFO within classes. Service times for class k are drawn from a general distribution function Bk (t). Using the method of phases and a resolution technique from the theory of Markov processes we obtain Laplace transforms of various distributions.

Three-Dimensional Simulation of Thermoelectric Devices With Compact Numerical Models

2003 ◽  
Author(s):  
Eric Prather ◽  
Bhalchandra Puranik
Keyword(s):  
Heat Source ◽  
Heat Sink ◽  
Numerical Models ◽  
Three Dimensional ◽  
Electronics Cooling ◽  
Step Function ◽  
Compact Model ◽  
Zone Model ◽  
Detailed Model ◽  
Source Power

Thermoelectric cooling modules (TECs) are widely used within electronic equipment for both temperature reduction and control of individual components. The techniques presented in this paper demonstrate that it is possible to construct a simple three-zone model, that represents the transient and 3D properties of a typical TEC, and can be easily built within existing CFD software packages for a known electric current or voltage input. A comparison of compact model results, detailed model results, and experimental results is presented for a typical electronics cooling setup, including a heat source (from which heat is absorbed by the TEC), TEC device, and air-cooled heat sink. Variables examined include heat source power dissipation, TEC current, and heat sink airflow. Finally, the response of the setup to a step function in current is examined to investigate the transient performance of the compact model.

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