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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Secondary processes induced by finite birth-and-death processes

Branford, Alan John. January 1980 (has links) (PDF)
Typescript (photocopy)
2

Secondary processes induced by finite birth-and-death processes.

Branford, Alan John. January 1980 (has links) (PDF)
Thesis (M.Sc.) -- University of Adelaide, Dept. of Applied Mathematics, 1982. / Typescript (photocopy).
3

Derivation of Moments during a Busy Period

Fan, Rocky Yuk-keung 09 1900 (has links)
The purpose of this project is to derive the first two moments of two random variables, that is, the number served during and the length of a busy period. Two singleserver models are discussed in this project, namely, the Mb°∕Ea∕ 1 model, and the Mb∕Mb∕1 model. Moreover, in the development, standard methods such as the moment generating function technique are used, application of a computer system will also be introduced. / Thesis / Master of Science (MSc)
4

Mathematical methods in queueing theory

Edwards, Jane Joan January 1965 (has links)
Thesis (M.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / The thesis deals with some of the mathematical techniques that are used in solving queueing theory problems. The organization of the paper is basically the same as that used by Goddard [3] in his treatment of queueing theory. The first method investigated is the analysis of queueing problems as Markovian processes. This analysis is due to D. G. Kendall [4,5] and is primarily for the case M/G/1. Formulas are found for E(n) and E(w). The limitations of this method in dealing with more general queues are mentioned. For the case M/M/s, the differential-difference equations are developed with examples of their use in machine breakdown problems and telephone trunk line congestion. The treatment is primarily for the case in which the system is in statistical equilibrium. The uses of Laplace transforms and probability generating functions are illustrated by Pollazoek's method of finding the moments of the waiting time distribution for the queue M/G/1. They are also shown in finding Pn(t) and Pn in an example of welders using a power supply. A method of expressing the distribution of the waiting time for the queue G/G/1, due to Lindley [7], is outlined at the conclusion of the paper. The result is an expression for the waiting time distribution in terms of the density function of the difference between the service time and inter-arrival time, rather than either density function separately. / 2031-01-01
5

Certain Static and Dynamic Priority Policies in Queueing Systems

Sarhangian, Vahid 20 December 2011 (has links)
In this thesis, we first study delay systems with different classes of impatient customers. We analyze the M/GI/1+M queue serving two priority classes under the static non-preemptive priority discipline. We also study the multi-server priority queue considering two cases depending on the time-to-abandon distribution being exponentially distributed or deterministic. In all models, we obtain the Laplace transforms of the virtual waiting time for each class by exploiting the level-crossing method. This enables us to obtain the steady-state system performance measures. In the second part, we consider the steady-state waiting time distributions of a two class M/GI/1 queue operating under a dynamic priority discipline. We find an accurate approximation for the steady-state waiting time distribution of the low-priority customers which allows us to study how they are penalized as the priority parameter increases. We also obtain bounds for the variance of the waiting time of high-priority customers.
6

Certain Static and Dynamic Priority Policies in Queueing Systems

Sarhangian, Vahid 20 December 2011 (has links)
In this thesis, we first study delay systems with different classes of impatient customers. We analyze the M/GI/1+M queue serving two priority classes under the static non-preemptive priority discipline. We also study the multi-server priority queue considering two cases depending on the time-to-abandon distribution being exponentially distributed or deterministic. In all models, we obtain the Laplace transforms of the virtual waiting time for each class by exploiting the level-crossing method. This enables us to obtain the steady-state system performance measures. In the second part, we consider the steady-state waiting time distributions of a two class M/GI/1 queue operating under a dynamic priority discipline. We find an accurate approximation for the steady-state waiting time distribution of the low-priority customers which allows us to study how they are penalized as the priority parameter increases. We also obtain bounds for the variance of the waiting time of high-priority customers.
7

Single and dual queueing schemes with prioritised traffic scheduling and finite waiting room

Bedford, Anthony, Anthony.bedford@rmit.edu.au January 2003 (has links)
Analysis of new schemes aimed at improving congestion in communications systems is vital for todays service providers. Many techniques are used to evaluate such schemes be it precisely via mathematics or approximately using simulation. This thesis introduces a new scheme, the multi priority dual queue (MPDQ). The MPDQ is the combination of two concepts, the dual queue introduced by [Hayes et. al., 1999] and prioritised traffic. The MPDQ is a system with finite waiting room with two queues where traffic upon arrival if finding the first queue full wait in the second queue if there is room. When a space becomes vacant in the first queue, a customer at the front of the second queue enters the back of the first, which is the queue that has the service centre at the front of it. The traffic can be of two or more classes. The analysis of such a system is complex, both analytically using queueing theory and approximately using simulation analysis. Both approaches are taken in this thesis. To begin, the new algorithmic approach used for the MPDQ is applied for the single buffer model. The steady state and waiting time distributions are obtained and later compared to the MPDQ. Next the performance characteristics are obtained by solving the steady state and waiting time distributions of a two class MPDQ. Preemptive and non-preemptive service disciplines are investigated. Maple is also used to solve the algorithm. To broaden the application of the MPDQ scheme, computer simulations using Arena are undertaken to extend the application of the scheme (and existing finite queueing models) to situations with more than two priorities, something that is extremely difficult to solve analytically. Using simulation, comparisons are undertaken for the single and dual queue schemes for more than two priorities with a variety of queueing disciplines used including First In First Out (FIFO), Last In First Out (LIFO), High Class First (HCF), and Low Class First (LCF). Network scenarios are also modelled to determine the performance of the MPDQ in this environment.
8

Evaluation by simulation of queueing network models of multiprogrammed computer systems /

Lester, Lewis Neale. January 1980 (has links) (PDF)
Thesis (Ph.D.)-- University of Adelaide, Dept. of Computing Science, 1982. / Typescript (photocopy).
9

On distributed scheduling for wireless networks with time-varying channels

Reddy, Akula Aneesh 17 July 2014 (has links)
Wireless scheduling is a fundamental problem in wireless networks that involves scheduling transmissions of multiple users in order to support data flows with as high rates as possible. This problem was first addressed by Tassuilas and Ephremides, resulting in the celebrated Back-Pressure network scheduling algorithm. This algorithm schedules network links to maximize throughput in an opportunistic fashion using instantaneous network state information (NSI), i.e., queue and channel state knowledge across the entire network. However, the Back-Pressure (BP) algorithm suffers from various drawbacks - (a) it requires knowledge of instantaneous NSI from the whole network, i.e. feedback about time-varying channel and queue states from all links of the network, (b) the algorithm requires solving a global optimization problem at each time to determine the schedule, making it highly centralized. Further, Back-pressure algorithm was originally designed for wireless networks where interference is modeled using protocol interference model. As recent break-throughs in full-duplex communications and interference cancelation techniques provide greatly increased capacity and scheduling flexibility, it is not clear how BP algorithm can be modified to improve the data rates and reduce the delay. In this thesis, we address the drawbacks of Back-Pressure algorithm to some extent. In particular, our first work provides a new scheduling algorithm (similar to BP) that allows users to make individual decisions (distributed) based on heterogeneously delayed network state information (NSI). Regarding the complexity issue, in our second work, we analyze the performance of the greedy version of BP algorithm, known as Greedy Maximal Scheduling (GMS) and understand the effect of channel variations on the performance of GMS. In particular, we characterize the efficiency ratio of GMS in wireless networks with fading. In our third and fourth work, we propose and analyze new scheduling algorithms that can benefit from new advancements in interference cancelation techniques. / text
10

Token passing medium access control protocol performance under asymmetric service

Pereira, Rubem Kicis Torrents January 1997 (has links)
No description available.

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