Dissertations / Theses: 'Queues'

1

Hernandez, Valencia Enrique Jose Posner Edward C. "Queues of queues in communication networks /." Diss., Pasadena, Calif. : California Institute of Technology, 1988. http://resolver.caltech.edu/CaltechETD:etd-11072007-090157.

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2

Zhang, Jiheng. "Limited processor sharing queues and multi-server queues." Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/34825.

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We study two classes of stochastic systems, the limited processor sharing system and the multi-server system. They share the common feature that multiple jobs/customers are being processed simultaneously, which makes the study of them intrinsically difficult. In the limited processor sharing system, a limited number of jobs can equally share a single server, and the excess ones wait in a first-in-first-out buffer. The model is mainly motivated by computer related applications, such as database servers and packet transmission over the Internet. This model is studied in the first part of the thesis. The multi-server queue is mainly motivated by call centers, where each customer is handled by an agent. The number of customers being served at any time is limited by number of agents employed. Customers who can not be served upon arrival wait in a first-in-first-out buffer. This model is studied in the second part of the thesis.

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3

Breuer, Lothar. "Spatial queues." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=961030135.

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4

Lim, David Eng Chung. "Investigation in to ramp queues vs. freeway queues on ramp metered freeways." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/1676.

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Freeways and highways form an integral part of any road network system demanding significant quantities of resources to plan and construct. During times of congestion and flow breakdown forms of traffic management are required to maintain the efficiency, reliability and safety of these high asset road facilities. Here within lies the responsibilities of traffic engineering professionals. The lack of adequate maintenance and management of any urban road network system hinders economic development and quality of life.Ramp metering is an active traffic management system implemented on high speed, free flowing facilities such as freeways and highways. This form of intelligent transport system has been applied to freeways throughout the world to regulate the intensity and demand proportion of freeway inflow during peak demand periods. The primary goal is to manage the existing roadway to operate at maximum efficiency. Main Roads Western Australia, the governing road authority in Western Australia is currently in a position to investigate the suitability of ramp metering on Western Australia's freeways.This research demonstrates how traffic movement and interaction can be mapped and characterised to identify forms of traffic flow breakdown that ramp metering has the potential to address. This research also documents the required components of ramp metering, how it should operate and the potential this active management system has to be applied over a system wide road network infrastructure.The Mitchell Freeway southbound direction undergoes significant forms of congestion and traffic flow breakdown during the morning peak period. A traffic characteristic of the Mitchell Freeway was developed to make an evaluation for the suitability of ramp metering as an effective management system. An analytical comparison between current freeway queues and theoretical on-ramp queues provided indication that the congestion and flow breakdown currently observed had the potential to be managed through ramp metering, ensuring the future sustainability of this vital freeway for the city of Perth, Western Australia.

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Jori, Alessandro. "Queues de Lifshitz magnétiques /." [S.l.] : [s.n.], 1998. http://library.epfl.ch/theses/?nr=1813.

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6

Dieker, Antonius Bernardus. "Extremes and fluid queues." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2006. http://dare.uva.nl/document/19721.

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7

Jones, Lee K., and Richard C. 1943 Larson. "Efficient Computation of Probabilities of Events Described by Order Statistics and Application to a Problem of Queues." Massachusetts Institute of Technology, Operations Research Center, 1991. http://hdl.handle.net/1721.1/5159.

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Consider a set of N i.i.d. random variables in [0, 1]. When the experimental values of the random variables are arranged in ascending order from smallest to largest, one has the order statistics of the set of random variables. In this note an O(N3) algorithm is developed for computing the probability that the order statistics vector lies in a given rectangle. The new algorithm is then applied to a problem of statistical inference in queues. Illustrative computational results are included.

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8

Roy, Kirk Andrew. "Laplace transforms, probabilities and queues." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ31000.pdf.

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9

Shalmon, Michael S. "Queues and packet multiplexing networks." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=71999.

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This thesis has to do with certain fundamental queues that are well established as models for delay in simple packet-switching concentrators and networks. We first revisit the single server queue with Poisson arrivals and general independent service times. We then work out a complete delay analysis for a traffic concentrating tandem network of queues with deterministic service and batch Poisson sources connected to every node; this is the most comprehensive analysis available for a network which is not of Jackson type. We also show how to (partially) extend the analysis to a concentrating tree network, and to an arrival process somewhat more general that batch Poisson.
The two parts of the thesis have a close methodological relationship. Our contribution in both cases is to rederive certain known results, and to produce a variety of new ones, using techniques that are essentially qualitative. Our particular view of the stochastic processes in question is guided by a very special queue discipline, namely Last Come First Served preemptive resume; by identifying certain structural features of the sample paths, one can read, almost without calculation, a host of statistics of common interest. The LCFS preemptive resume discipline also enables us: (i) to strengthen the connection between the single server queue with general independent service times and interarrival times, and the fluctuation theory of random walks; (ii) to strengthen the connection between the queue with Poisson arrivals and branching processes.

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10

Baber, Jack Martyn Alec. "Queues in series with blocking." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/54697/.

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This piece of work describes a hospital's Critical Care Unit and uses different mathematical techniques to model the behaviour seen there. The main factor that is included in these models is the problem of bed blocking in the Unit. Blocking is defined as patients who are well enough not to be in the Critical Care Unit, but remain there, for any number of reasons. These patients are using up an expensive and limited resource. The mathematical techniques that the models are built on are extensively reviewed and analysed. These are the Coxian Phase Type Distribution and Networks of Queues with Blocking Equations. Both techniques are described in detail and their distributions analysed under different circumstances. The final chapter shows how the two distributions can be used to model a complex situation such as the one found in the Critical Care Unit. The models are tested and compared. Finally, the models are tested under a number of 'what if scenarios to predict the effect of changing certain factors on the actual Unit.

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11

Wortman, M. A. "Vacation queues with Markov schedules." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/54468.

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Vacation systems represent an important class of queueing models having application in both computer communication systems and integrated manufacturing systems. By specifying an appropriate server scheduling discipline, vacation systems are easily particularized to model many practical situations where the server's effort is divided between primary and secondary customers. A general stochastic framework that subsumes a wide variety of server scheduling disciplines for the M/GI/1/L vacation system is developed. Here, a class of server scheduling disciplines, called Markov schedules, is introduced. It is shown that the queueing behavior M/GI/1/L vacation systems having Markov schedules is characterized by a queue length/server activity marked point process that is Markov renewal and a joint queue length/server activity process that is semi-regenerative. These processes allow characterization of both the transient and ergodic queueing behavior of vacation systems as seen immediately following customer service completions, immediately following server vacation completions, and at arbitrary times The state space of the joint queue length/server activity process can be systematically particularized so as to model most server scheduling disciplines appearing in the literature and a number of disciplines that do not appear in the literature. The Markov renewal nature of the queue length/server activity marked point process yields important results that offer convenient computational formulae. These computational formulae are employed to investigate the ergodic queue length of several important vacation systems; a number of new results are introduced. In particular, the M/GI/1 vacation with limited batch service is investigated for the first time, and the probability generating functions for queue length as seen immediately following service completions, immediately following vacation completions, and at arbitrary times are developed.
Ph. D.

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12

Thiyagarajah, Murali (Muralitharam) Carleton University Dissertation Computer Science. "Permutational power of priority queues." Ottawa, 1993.

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13

He, Shuangchi. "Many-server queues with customer abandonment." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41185.

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Customer call centers with hundreds of agents working in parallel are ubiquitous in many industries. These systems have a large amount of daily traffic that is stochastic in nature. It becomes more and more difficult to manage a call center because of its increasingly large scale and the stochastic variability in arrival and service processes. In call center operations, customer abandonment is a key factor and may significantly impact the system performance. It must be modeled explicitly in order for an operational model to be relevant for decision making. In this thesis, a large-scale call center is modeled as a queue with many parallel servers. To model the customer abandonment, each customer is assigned a patience time. When his waiting time for service exceeds his patience time, a customer abandons the system without service. We develop analytical and numerical tools for analyzing such a queue. We first study a sequence of G/G/n+GI queues, where the customer patience times are independent and identically distributed (iid) following a general distribution. The focus is the abandonment and the queue length processes. We prove that under certain conditions, a deterministic relationship holds asymptotically in diffusion scaling between these two stochastic processes, as the number of servers goes to infinity. Next, we restrict the service time distribution to be a phase-type distribution with d phases. Using the aforementioned asymptotic relationship, we prove limit theorems for G/Ph/n+GI queues in the quality- and efficiency-driven (QED) regime. In particular, the limit process for the customer number in each phase is a d-dimensional piecewise Ornstein-Uhlenbeck (OU) process. Motivated by the diffusion limit process, we propose two approximate models for a GI/Ph/n+GI queue. In each model, a d-dimensional diffusion process is used to approximate the dynamics of the queue. These two models differ in how the patience time distribution is built into them. The first diffusion model uses the patience time density at zero and the second one uses the entire patience time distribution. We also develop a numerical algorithm to analyze these diffusion models. The algorithm solves the stationary distribution of each model. The computed stationary distribution is used to estimate the queue's performance. A crucial part of this algorithm is to choose an appropriate reference density that controls the convergence of the algorithm. We develop a systematic approach to constructing a reference density. With the proposed reference density, the algorithm is shown to converge quickly in numerical experiments. These experiments also show that the diffusion models are good approximations of queues with a moderate to large number of servers.

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14

Ramachandran, Karuna. "Matrix geometric methods in priority queues." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq28517.pdf.

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15

Alnowibet, Khalid Abdulaziz. "Nonstationary Erlang Loss Queues and Networks." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-04222004-192735/.

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The nonstationary Erlang loss model is a queueing system consisting of a finite number of servers and no waiting room with a nonstationary arrival process or a time-dependent service rate. The Erlang loss model is commonly used to model and evaluate many communication systems. Often, these types of service systems encounter a change in the arrival rate over time while the service rate remains either constant or changes very little over time. In view of this, the focus in this research is the nonstationary Erlang loss queues and network with time-dependent arrival rate and constant service rate. We developed an iterative scheme referred to as the fixed point approximation (FPA) in order to obtain the time-dependent blocking probability and other measures for a single-class nonstationary Erlang loss queue and a nonstationary multi-rate Erlang loss queue. The FPA method was compared against exact numerical results, and two other methods, namely, MOL and PSA, for various nonstationary Erlang loss queues with sinusoidal arrival rates. Although we used sinusoidal functions to model the time-dependent arrival rate, the solution can be obtained for any arrival rate function. Experimental results demonstrate that the FPA algorithm provides an exact solution for nonstationary Erlang loss queue. The FPA algorithm was also applied to the case of multi-rate nonstationary Erlang loss queues and the results obtained were compared with simulation. We generalized the FPA algorithm for networks of nonstationary Erlang loss queues with Markovian branching, and compared its accuracy to simulation. Finally, FPA was used to analyze networks of nonstationary Erlang loss queues with population constraints. Numerical results showed that FPA provides a good approximation.

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16

Farrar, Timothy Martin. "Resource allocation in systems of queues." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260462.

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17

Moriarty, John. "Queues, directed percolation and directed polymers." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433363.

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18

Izady, Navid. "On queues with time-varying demand." Thesis, Lancaster University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551633.

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The service sector lies at the heart of industrialized societies. Since the early decades of the twentieth century queueing theory has provided service managers with a mathematical framework to evaluate the operational service quality and service efficiency of their services, and to strive for a balance between the two aspects. Unlike most textbook queueing models, however, real service operations have time-varying arrival rates, usually with significant variations over a day. This non-stationarity of the arrival process, which often coincides with time-varying staffing levels; makes queueing models difficult to analyze. Two of the important problems arising when considering time-dependent queues concern service quality evaluation of queues with given parameters in terms of measures like customers' waiting times, and finding the minimal time-dependent staffing levels required for achieving a given service quality target. The former is addressed in the first part of the thesis, and the latter is addressed in the second part. In the first part of the thesis, we evaluate the potential and limitations of numerical methods and investigate approximation approaches proposed in the literature for service quality evaluation of time-dependent single and multiple facility queues. We also propose, implement, and test a novel approximation approach for service quality evaluation of a particular type of time-dependent queues, namely single-class, multi-class, and networks of loss queues. Combining an exact equation derived using infinite-server models with an approximate equation motivated by stationary loss models, the proposed approach produces close to exact results in very short times. The second part of the thesis is dedicated to the staffing problem of non-stationary service networks. In particular, we focus on complex services provided by English emergency departments where a Government set waiting time target must be achieved. Drawing upon infinite-server models' results and a square root staffing law as well as the strength and flexibility of simulation models, we propose a new heuristic approach for staffing emergency departments, based on the concept of time-stable performance. The approach accounts for complexities like multiple classes of customers and resource sharing, and is shown to achieve the desired target while saving some staff-hours in typical situations where staffing levels do not allow properly for the time lags in the workloads.

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19

Martin, Simon P. "Routing and transfers amongst parallel queues." Thesis, University of Newcastle Upon Tyne, 2008. http://hdl.handle.net/10443/2051.

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This thesis is concerned with maximizing the performance of policies for routing and transferring jobs in systems of heterogeneous servers. The tools used are probabilistic modelling, optimization and simulation. First, a system is studied where incoming jobs are allocated to the queue belonging to one of a number of servers, each of which goes through alternating periods of being operative and inoperative. The objective is to evaluate and optimize performance and cost metrics. Jobs incur costs for the amount of time that they spend in a queue, before commencing service. The optimal routing policy for incoming jobs is obtained by solving numerical programming equations. A number of heuristic policies are compared against the optimal, and one dynamic routing policy is shown to perform well over a large range of parameters. Next, the problem of how best to deal with the transfer of jobs is considered. Jobs arrive externally into the queue attached to one of a number of servers, and on arrival are assigned a time-out period. Jobs whose time-out period expires before it commences service is instantaneously transferred to the end another queue, based on a routing policy. Upon transfer, a transfer cost is incurred. An approximation to the optimal routing policy is computed, and compared with a number of heuristic policies. One heuristic policy is found to perform well over a large range of parameters. The last model considered is the case where incoming jobs are allocated to the queue attached to one of a number of servers, each of which goes through periods of being operative and inoperative. Additionally, each job is assigned a time-out on arrival into a queue. Any job whose time-out period expires before it commences service is instantaneously transferred to the end of another queue, based on a transfer policy. The objective is to evaluate and optimize performance and cost metrics. Jobs incur costs for the amount of time that they spend in a queue, before commencing service, and additionally incur a cost for each transfer they experience. A number of heuristic transfer policies are evaluated and one heuristic which performs for a wide range of parameters is observed.

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20

Jones, Gareth. "Modelling bursty flows with fluid queues." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/25093.

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Many modern systems must deal with bursty traffic, from computer systems subject to jobs arriving in clusters to devices with an intermittent energy supply such as those powered by renewable sources. As computer systems become ever more commonplace, and renewable energy targets make unreliable power ubiquitous, an important part of system design will be ensuring system performance under bursty demand. We seek to understand the impact of bursty arrivals and show how system parameters can be chosen to meet service requirements in these situations. In this thesis, we will be concerned with the fluid queue, a modelling paradigm for systems subject to bursty arrivals. Fluid queues describe the evolution of a stochastic buffer fed by a source which changes rate according to a background process, typically a continuous-time Markov chain. We choose this model as it captures the key behaviour we wish to model and the characteristics we seek to compute are amenable to efficient solution. In this thesis we make three contributions to the theory of fluid queues, significantly increasing the class of systems which can be modelled without resorting to experiments or simulations. Firstly, we derive hitting times in models with multi-regime (level-dependent) behaviour, then busy periods in models where the environment process has an infinite (but countable) state space such as the M/M/c queue, and finally performance metrics in networks of fluid queues. We apply such models to give insights into mobile phone battery life, the temperature of a computer system and reserve levels in energy storage reservoirs, all systems subject to bursty arrivals.

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21

Girimurugan, Senthil Balaji. "Tandem queues with non-stationary arrivals." Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1249065512/.

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22

Fralix, Brian Haskel. "Stability and Non-stationary Characteristics of Queues." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14569.

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We provide contributions to two classical areas of queueing. The first part of this thesis focuses on finding new conditions for a Markov chain on a general state space to be Harris recurrent, positive Harris recurrent or geometrically ergodic. Most of our results show that establishing each property listed above is equivalent to finding a good enough feasible solution to a particular optimal stopping problem, and they provide a more complete understanding of the role Foster's criterion plays in the theory of Markov chains. The second and third parts of the thesis involve analyzing queues from a transient, or time-dependent perspective. In part two, we are interested in looking at a queueing system from the perspective of a customer that arrives at a fixed time t. Doing this requires us to use tools from Palm theory. From an intuitive standpoint, Palm probabilities provide us with a way of computing probabilities of events, while conditioning on sets of measure zero. Many studies exist in the literature that deal with Palm probabilities for stationary systems, but very few treat the non-stationary case. As an application of our main results, we show that many classical results from queueing (in particular ASTA and Little's law) can be generalized to a time-dependent setting. In part three, we establish a continuity result for what we refer to as jump processes. From a queueing perspective, we basically show that if the primitives and the initial conditions of a sequence of queueing processes converge weakly, then the corresponding queue-length processes converge weakly as well in some sense. Here the notion of convergence used depends on properties of the limiting process, therefore our results generalize classical continuity results that exist in the literature. The way our results can be used to approximate queueing systems is analogous to the way phase-type random variables can be used to approximate other types of random variables.

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23

Labrèche, Nadine. "Overloading a Jackson network of shared queues." Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/9601.

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Jackson networks with finite buffers can be designed so that buffer overflows occur with very low probability. Still, queues can be filled beyond capacity so it is of interest to study the distribution of such occurrences and, as a measure of the reliability of the system, the mean time until an overload. The approach we propose is based on a change of measure which twists the stationary Jackson network into a process for which overloads are frequent. For a Jackson network of shared queues with buffer of size $\ell - 1$, we show that the stationary overflow distribution of the twisted network can be used to determine both the limiting distribution (as $\ell\to\infty$) at the moment of overload and the mean time until overload of the original Jackson network. Our estimation for the mean time until an overload is based on an article by Iscoe and McDonald (1994a) in which the mean time until the overflow of a Jackson network is estimated by the reciprocal of the smallest eigenvalue $\Lambda(B)$ of an associated Dirichlet problem. The distinct feature of this estimate is that it comes complete with error bounds so that, unlike estimators, its accuracy can be evaluated. Of course, in practice such eigensystems, however, we obtain an estimate which we show to be asymptotically equivalent to the one proposed by Aldous (1989).

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24

Iravani, Seyed Mohammad Reza. "Tandem queues attended by a moving server." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ27963.pdf.

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25

Peterson, Sonja. "Product-form networks of queues with signals /." Hamburg : Univ. Hamburg, Fb. Mathematik, Inst. für Math. Stochastik, 1999. http://www.gbv.de/dms/zbw/268360650.pdf.

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26

Chin, Ke-Tsai Edward. "Networks of queues with state-dependent flows." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/25419.

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Siew, Christine Chiu Hsia. "Task allocation policies for State Dependent queues." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/63041.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 108-111).
Consider a model of a dynamical queue with deterministic arrival and service rates, where the service rate depends on the server utilization history. This proposed queueing model occurs in many practical situations. for example in human-in-the-loop systems where widely accepted empirical laws describe human performance as a function of mental arousal, which increases when the human is working on a task and decreases otherwise. Formal methods for task management in state-dependent dynamical queues are gathering increasing attention to improve the efficiency of such systems. The focus of this research is hence to design maximally stabilizing task release control policies to maximize the useful throughput of such a system. Assuming that the error probability of a server is also related to its state., the useful throughput can be defined as the number of successfully completed tasks per unit time. Monitoring of both service and error rates is particularly typical in the realm of human-in-the-loop and production systems. This research focuses on developing policies to minimize both these penalty measures. For a server with deterministic service rate, the optimal policy is found to be a threshold policy that releases a task to the server only when the server state is less than or equal to a certain threshold. Assuming homogeneous tasks that bring in the same deterministic amount of work to be done, it can be shown that an appropriate threshold policy is maximally stabilizing and that this threshold value can be uniquely determined. This work is then further extended to the case when the server behaves stochastically and verified using simulation. Finally, a proof-of-concept experiment is proposed and developed to test the feasibility of the proposed theoretical policies in real-world settings. The experiment consisted of completing multiple-choice verbal analogy questions and the results confirm the effect of workload control in improving human performance.
by Christine Chiu Hsia Siew.
S.M.

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28

Diaz, Jean-Pierre. "Processus non standard et queues de distribution." Paris 6, 1989. http://www.theses.fr/1989PA066142.

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Nous etablissons des methodes de prevision pour la loi du maximum d'une suite de variables independantes de meme loi, attire par une loi de frechet. Les resultats sont ensuite generalises au domaine d'attraction des lois de weibull, ainsi qu'au jeme maximum (j fixe). Nous nous interessons, dans un deuxieme temps aux processus auto-semblables et a l'analyse r sur s. Nous proposons un test de detection de dependances a long terme. Nous envisageons ensuite un filtre permettant de supprimer de telles correlations

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29

Magalhaes, Marcos N. "Queues with a Markov renewal service process." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53582.

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In the present work, we study a queue with a Markov renewal service process. The objective is to model systems where different customers request different services and there is a setup time required to adjust from one type of service to the next. The arrival is a Poisson process independent of the service. After arrival, all the customers will be attended in order of arrival. Immediately before a service starts, the type of next customer is chosen using a finite, irreducible and aperiodic Markov chain P. There is only one server and the service time has a distribution function F_ij, where i and j are the types of the previous and current customer in service, respectively. This model will be called M/MR/l. Embedding at departure epochs, we characterize the queue length and the type of customer as a Markov renewal process. We study a special case where F_ij, is exponential with parameter μ_ij. We prove that the departure is a renewal process if and only if μ_ij = μ , A i j ε E. Furthermore, we show that this renewal is a Poisson process. The type-departure process is extensively studied through the respective counting processes. The crosscovariance and the crosscorrelation are computed and numerical results are shown. Finally, we introduce several expressions to study the interdependence among the type·departure processes in the general case, i.e. the distribution function F_ij, does not have any special form.
Ph. D.

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30

Dalhoumi, Mohamed Néjib. "Sur l'estimation de probabilités de queues multivariées." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS061/document.

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Cette thèse présente des contributions à la modélisation multivariée des queues de distribution. Nous introduisons une nouvelle modélisation des probabilités de queue jointes d'une distribution multivariée avec des marges Pareto. Ce modèle est inspiré de celui de Wadsworth et Tawn (2013). Une nouvelle variation régulière multivariée non-standard de coefficient une fonction à deux variables est introduite, permettant de généraliser deux approches de modélisation respectivement proposées par Ramos et Ledford (2009)et Wadsworth et Tawn (2013). En nous appuyant sur cette modélisation nous proposons une nouvelle classe de modèles semi-paramétriques pour l'extrapolation multivariée selon des trajectoires couvrant tout le premier quadrant positif. Nous considérons aussi des modèles paramétriques construits grâce à une mesure non-négative satisfaisant une contrainte qui généralise celle de Ramos et Ledford (2009). Ces nouveaux modèles sont flexibles et conviennent tant pour les situations de dépendance que d'indépendance asymptotique
This PhD thesis presents contributions to the modelling of multivariate extremevalues. We introduce a new tail model for multivariate distribution with Pareto margins. This model is inspired from the Wadsworth and Tawn (2013) one. A new non-standard multivariate regular variation with index equals to a function of two variables is thus introduced to generalize both modeling approaches proposedby Ramos and Ledford (2009) and Wadsworth and Tawn (2013), respectively. Building on this new approach we propose a new class of non-parametric models allowing multivariate extrapolation along trajectories covering the entire first positive quadrant. Similarly we consider parametric models built with a non-negative measure satisfying a constraint that generalizes the Ramos and Ledford (2009) one. These new models are flexible and valid in both situations of dependence or asymptotic independence

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Aleiyouka, Mohalilou. "Sur la dépendance des queues de distributions." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMLH28/document.

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Pour modéliser de la dépendance entre plusieurs variables peut s'appuyer soit sur la corrélation entre les variables, soit sur d'autres mesures, qui déterminent la dépendance des queues de distributions.Dans cette thèse, nous nous intéressons à la dépendance des queues de distributions, en présentant quelques propriétés et résultats.Dans un premier temps, nous obtenons le coefficient de dépendance de queue pour la loi hyperbolique généralisée selon les différentes valeurs de paramètres de cette loi.Ensuite, nous exposons des propriétés et résultats du coefficient de dépendance extrémale dans le cas où les variables aléatoires suivent une loi de Fréchet unitaire.Finalement, nous présentons un des systèmes de gestion de bases de données temps réel (SGBDTR). Le but étant de proposer des modèles probabilistes pour étudier le comportement des transactions temps réel, afin d'optimiser ses performances
The modeling of the dependence between several variables can focus either on the positive or negative correlation between the variables, or on other more effective ways, which determine the tails dependence of distributions.In this thesis, we are interested in the tail dependence of distributions, by presenting some properties and results. Firstly, we obtain the limit tail dependence coefficient for the generalized hyperbolic law according to different parameter values of this law. Then, we exhibit some properties and results of die extremal dependence coefficient in the case where the random variables follow a unitary Fréchet law.Finally, we present a Real Time Database ManagementSystems (RDBMS). The goal is to propose probabilistic models to study thebehavior of real-time transactions, in order to optimize its performance

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Green, David Anthony. "Departure processes from MAP/PH/1 queues." Title page, contents and abstract only, 1999. http://thesis.library.adelaide.edu.au/public/adt-SUA20020815.092144.

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Bibliography: leaves 145-150. Electronic publication; Full text available in PDF format; abstract in HTML format. A MAP/PH/1 queue is a queue having a Markov arrival process (MAP), and a single server with phase-type (PH-type) distributed service time. This thesis considers the departure process of these types of queues, using matrix analytic methods, the Jordan canonical form of matrices, non-linear filtering and approximation techniques. Electronic reproduction.[Australia] :Australian Digital Theses Program,2001.

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Harada, Douglas Yugi Bocal [UNESP]. "Entendendo as filas de espera: uma abordagem para o Ensino Médio." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/151565.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O tempo de espera é uma variável muito estudada em nosso cotidiano e não pode ser desconsiderada ou minimizada, principalmente quando algum tempo é tomado de uma pessoa por outras que não respeitam uma ordenação estabelecida em sistemas de atendimento. No caso das filas, isso poderia ser evitado em boa parte, se todos entendessem sua estrutura e sua finalidade. Esta investigação tem como objetivo desenvolver um aprendizado sobre sistemas de filas e suas possíveis aplicações, além de estabelecer alguns aspectos educacionais sobre esse assunto. Este estudo foi desenvolvido no âmbito escolar, considerando o caso da educação em filas. A investigação iniciou-se com pesquisa bibliográfica de aspectos teóricos sobre filas e sobre os conceitos de tempo de espera, tipos de filas e suas aplicações. Seguidamente, foi realizado um questionário referente à estrutura de filas e sua educação básica, com a finalidade de avaliar o nível de conhecimento dos alunos. Após a aplicação dessa etapa, foi realizada uma apresentação sobre o tema tratado e, em seguida, aplicação de outro questionário, a fim de analisar a existência de melhoria na aprendizagem. Com o desenvolvimento e aplicação deste estudo, foi possível concluir que houve significativo ganho de conhecimento e de aprendizado dos alunos com relação à educação de filas e seus aspectos. Como motivações aos alunos, foram realizadas duas aplicações simples de filas com comportamentos distintos: uma situação em que os alunos presenciam no seu cotidiano, a fila da cantina, e outra com a teoria mais conhecida e regularmente aplicada. As situações estudadas fornecem subsídios aos alunos na compreensão e na aplicação da teoria em sistemas de filas de espera.
Waiting time is a very studied variable in our daily life and can not be disregarded or minimized, especially when some time is taken from a person by others who do not respect an ordering established in care systems. In the case of queues, this could be largely avoided if everyone understood its structure and purpose. This research aims to develop a learning about queuing systems and their possible applications, besides establishing some educational aspects about this subject. This study was developed in the school context, considering the case of education in queues. The investigation began with a bibliographical research of theoretical aspects about queues and about the concepts of waiting time, types of queues and their applications. Next, a questionnaire was carried out regarding the structure of queues and their basic education, with the purpose of evaluating the students' level of knowledge. After the application of this step, a presentation was made on the subject treated and then application of another questionnaire, in order to analyze the existence of improvement in learning. With the development and application of this study, it was possible to conclude that there was a significant gain in the knowledge and learning of students regarding the education of queues and their aspects. As motivations to the students, two simple applications of queues with different behaviors were carried out: a situation in which the students see in their daily lives, the canteen queue, and another with the best known and regularly applied theory. The situations studied provide support for students in the understanding and application of the theory in queuing systems.

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34

Yang, Jing pei. "A Design of Buffer Scheme by Using Data Filter for Solid State Disk." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1277132119.

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Tuan, Phung Duc. "Retrial Queues and their Applications in Communication Systems." 京都大学 (Kyoto University), 2011. http://hdl.handle.net/2433/142135.

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Drekic, Stevo. "Methods to reduce delay in preemptive priority queues." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0009/NQ42514.pdf.

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Huo, Jiale. "On testing concurrent systems through contexts of queues." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102987.

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Concurrent systems, including asynchronous circuits, computer networks, and multi-threaded programs, have important applications, but they are also very complex and expensive to test. This thesis studies how to test concurrent systems through contexts consisting of queues. Queues, modeling buffers and communication delays, are an integral part of the test settings for concurrent systems. However, queues can also distort the behavior of the concurrent system as observed by the tester, so one should take into account the queues when defining conformance relations or deriving tests. On the other hand, queues can cause state explosion, so one should avoid testing them if they are reliable or have already been tested. To solve these problems, we propose two different solutions. The first solution is to derive tests using some test selection criteria such as test purposes, fault coverage, and transition coverage. The second solution is to compensate for the problems caused by the queues so that testers do not discern the presence of the queues in the first place. Unifying the presentation of the two solutions, we consider in a general testing framework partial specifications, various contexts, and a hierarchy of conformance relations. Case studies on test derivation for asynchronous circuits, communication protocols, and multi-threaded programs are presented to demonstrate the applications of the results.

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Böhm, Walter. "Lattice path counting and the theory of queues." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 2008. http://epub.wu.ac.at/1086/1/document.pdf.

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In this paper we will show how recent advances in the combinatorics of lattice paths can be applied to solve interesting and nontrivial problems in the theory of queues. The problems we discuss range from classical ones like M^a/M^b/1 systems to open tandem systems with and without global blocking and to queueing models that are related to random walks in a quarter plane like the Flatto-Hahn model or systems with preemptive priorities. (author´s abstract)
Series: Research Report Series / Department of Statistics and Mathematics

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Coulombe, Michael Joseph. "MergeArray and scalable, relaxed, concurrent, mergeable priority queues." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99867.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.
Title as it appears in MIT Commencement Exercises program, June 5, 2015: MergeArray and scalable, concurrent, relaxed, mergeable priority queues. Cataloged from PDF version of thesis.
Includes bibliographical references (pages 62-63).
The priority queue is a well-studied data structure which has prospered in the ever-growing field of distributed computing. However, in the asynchronous shared-memory model, one operation was left behind: merge. I present the MergeArray, a framework for implementing scalable, relaxed, concurrent, and mergeable objects, which exploits disjoint access parallelism by using an array of sequential objects and performs merges lazily, index-by-index. I use MergeArray to build a linearizable and scalable priority queue with lock-free merge and insert and a relaxed, deadlock-free remove-min with expected worst-case rank-error of O(plogp) for p threads under common assumptions. I show experimental evidence that supports this rank-error estimate in practice as well as increased performance and scalability on a relaxed Minimum Spanning Tree benchmark compared to SprayList, a cutting-edge relaxed priority queue.
by Michael Joseph Coulombe.
S.M.

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Ishizaki, Fumio. "STUDIES ON DISCRETE-TIME QUEUES WITH CORRELATED ARRIVALS." Kyoto University, 1996. http://hdl.handle.net/2433/160809.

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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである
Kyoto University (京都大学)
0048
新制・論文博士
博士(工学)
乙第9308号
論工博第3138号
新制||工||1047(附属図書館)
UT51-96-T528
(主査)教授長谷川利治, 教授茨木俊秀, 教授金澤正憲
学位規則第4条第2項該当

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Kratz, Marie. "Statistique des queues de distribution et approximation poissonnienne." Paris 6, 1993. http://www.theses.fr/1993PA066135.

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Ce travail aborde des problemes lies a la theorie des valeurs extremes par le biais de l'approximation poissonnienne. Il est constitue de deux parties, selon que les variables aleatoires sont independantes ou non. La premiere partie, en deux chapitres, permet de passer en revue les diverses methodes proposees. Le premier chapitre traite de l'approximation poissonnienne des sommes de bernoulli. On s'interesse particulierement a deux methodes: la methode des semi-groupes d'operateurs associee aux techniques de couplage proposee par deheuvels et pfeifer et la methode de stein-chen utilisee par barbour. Apres avoir fait une synthese des differents resultats obtenus selon les methodes d'approximation et les metriques choisies, on compare les qualites respectives de ces resultats. Le second chapitre est une etude de l'approximation poissonnienne du processus empirique. De bons resultats sont obtenus par une methode directe tres simple, ne faisant pas appel aux techniques precedentes (note soumise au c. R. A. S. ). Dans la seconde partie, on s'interesse a l'approximation poissonnienne du processus des excedences. Apres un rappel des resultats classiques de la theorie des extremes, on traite plus specifiquement le cas des processus gaussiens, non sans importance en pratique. On calcule en particulier la vitesse de convergence du nombre d'excedences de suites normales non stationnaires (ce sujet a donne lieu a un article ecrit en collaboration avec j. Husler), puis l'on considere le probleme de l'evaluation de la vitesse de convergence du processus empirique gaussien vers un processus de poisson sous certaines conditions de melangeance. Cette etude fait l'objet d'un article, en preparation, ecrit en collaboration avec h. Rootzen

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Weber, Theophane. "Conditional dynamics of non-Markovian, infinite-server queues." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32339.

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Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2005.
Includes bibliographical references (p. 75-79).
We study the transient dynamics of a partially observed, infinite server queue fed with a Poisson arrival process whose controlled rate is changed at discrete points in time. More specifically, we define a state that incorporates partial information from the history of the process and write analytical formula for the dynamics of the system (state transition probabilities). Moreover, we develop an approximation method that makes the state finite-dimensional, and introduce techniques to further reduce the dimension of the state. This method could thus enable the formulation of tractable DPs in the future.
by Theophane Weber.
S.M.

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43

Srinivasan, Rengarajan Carleton University Dissertation Mathematics. "Topics in state dependent queues and queueing networks." Ottawa, 1988.

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Shawaly, El-Sayed Abdel-Azim. "Queue lengths and delays at oversaturated traffic signal-controlled intersections." Thesis, University of Sheffield, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327891.

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Da, Silva Soares Ana. "Fluid queues: building upon the analogy with QBD processes." Doctoral thesis, Universite Libre de Bruxelles, 2005. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211053.

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Les files d'attente fluides sont des processus markoviens à deux dimensions, où la première composante, appelée le niveau, représente le contenu d'un réservoir et prend des valeurs continues, et la deuxième composante, appelée la phase, est l'état d'un processus markovien dont l'évolution contrôle celle du niveau. Le niveau de la file fluide varie linéairement avec un taux qui dépend de la phase et qui peut prendre n'importe quelle valeur réelle.

Dans cette thèse, nous explorons le lien entre les files fluides et les processus QBD, et nous appliquons des arguments utilisés en théorie des processus de renouvellement pour obtenir la distribution stationnaire de plusieurs modèles fluides.

Nous commençons par l'étude d'une file fluide avec un réservoir de taille infinie; nous déterminons sa distribution stationnaire, et nous présentons un algorithme permettant de calculer cette distribution de manière très efficace. Nous observons que la distribution stationnaire de la file fluide de capacité infinie est très semblable à celle d'un processus QBD avec une infinité de niveaux. Nous poursuivons la recherche des similarités entre les files fluides et les processus QBD, et nous étudions ensuite la distribution stationnaire d'une file fluide de capacité finie. Nous montrons que l'algorithme valable pour le cas du réservoir infini permet de calculer toutes les quantités importantes du modèle avec un réservoir fini.

Nous considérons ensuite des modèles fluides plus complexes, de capacité finie ou infinie, où le comportement du processus markovien des phases peut changer lorsque le niveau du réservoir atteint certaines valeurs seuils. Nous montrons que les méthodes développées pour des modèles classiques s'étendent de manière naturelle à ces modèles plus complexes.

Pour terminer, nous étudions les conditions nécessaires et suffisantes qui mènent à l'indépendance du niveau et de la phase d'une file fluide de capacité infinie en régime stationnaire. Ces résultats s'appuient sur des résultats semblables concernant des processus QBD.

Markov modulated fluid queues are two-dimensional Markov processes, of which the first component, called the level, represents the content of a buffer or reservoir and takes real values; the second component, called the phase, is the state of a Markov process which controls the evolution of the level in the following manner: the level varies linearly at a rate which depends on the phase and which can take any real value.

In this thesis, we explore the link between fluid queues and Quasi Birth-and-Death (QBD) processes, and we apply Markov renewal techniques in order to derive the stationary distribution of various fluid models.

To begin with, we study a fluid queue with an infinite capacity buffer; we determine its stationary distribution and we present an algorithm which performs very efficiently in the determination of this distribution. We observe that the equilibrium distribution of the fluid queue is very similar to that of a QBD process with infinitely many levels. We further exploit the similarity between the two processes, and we determine the stationary distribution of a finite capacity fluid queue. We show that the algorithm available in the infinite case allows for the computation of all the important quantities entering in the expression of this distribution.

We then consider more complex models, of either finite or infinite capacities, in which the behaviour ff the phase process may change whenever the buffer is empty or full, or when it reaches certain thresholds. We show that the techniques that we develop for the simpler models can be extended quite naturally in this context.

Finally, we study the necessary and sufficient conditions that lead to the independence between the level and the phase of an infinite capacity fluid queue in the stationary regime. These results are based on similar developments for QBD processes.
Doctorat en sciences, Spécialisation mathématiques
info:eu-repo/semantics/nonPublished

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46

Cheung, Sing Kwong. "Processor-sharing queues and resource sharing in wireless LANs." Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/57875.

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Chang, Kuo-Hwa. "Extreme queues and stationarity of heavy-traffic service systems." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/25441.

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Farajian, Patrick. "Dynamic input rate control in queues with feedback delay." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=26386.

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The signal propagation delays in a high speed, wide area telecommunication network can be orders of magnitude larger than a message transmission time. This implies that the response times associated with dynamic congestion management strategies can be long relative to the characteristic times of the queue-length processes being controlled, and that such strategies may be of limited use in controlling message loss in high speed settings. We examine the interplay between signal propagation delays and efficiency of feedback-based congestion controls in the case of a very simple network model consisting of a single multiplexor serving a remote source population. We establish, using simulations of two simple approaches described in the literature, that loss performance can be very sensitive to propagation delay, and that response times can be diminished, for given propagation delays, by applying a rate-based, or cyclic, service strategy at the multiplexor output line in place or First-In, First-Out. We develop an optimization framework for the control problem, enabling the use of Markov Decision Programming to calculate the form and performance of feedback-based controllers which are optimal in terms of the trade-off achieved between forced losses at the network boundary and congestion-induced losses in the network interior. Observing that performance can be made insensitive to signal propagation delays by means of appropriate buffer dimensioning, we develop an asymptotic analysis of the buffer requirements, applicable in the limit of large values of the delay/bandwidth product.

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Böhm, Walter, and Sri Gopal Mohanty. "M/M/1 Queues under N-policy involving Batches." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 1990. http://epub.wu.ac.at/1784/1/document.pdf.

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Böhm, Walter, and Sri Gopal Mohanty. "On Discrete Time Markovian N-policy Queues involving Batches." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 1991. http://epub.wu.ac.at/1716/1/document.pdf.

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Consider two Markovian N-policy queueing models in discrete time, one with batch arrival, the other with batch service. In this paper the transient behaviour of both models is studied and the analogous continuous time results are achieved by a limiting process. The steady state solution for the model with batch arrival is derived. (author's abstract)
Series: Forschungsberichte / Institut für Statistik

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Dissertations / Theses on the topic 'Queues'

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