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Autor Artalejo, Jesús R. |
Documentos disponibles escritos por este autor (84)
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In this work, we present a bibliography on retrial queues which updates the bibliography published in this journal in Artalejo (1999) [7]. The bibliography is focused on the progress made during the last decade 2000–2009. For the sake of complet[...]![]()
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In this paper, we consider a discrete-time queue of Geo/Geo/c type with geometric repeated attempts. It is known that its continuous counterpart, namely the M/M/c queue with exponential retrials, is analytically intractable due to the spatial he[...]![]()
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In this paper the distribution of the maximum number of customers in a retrial orbit for a single server queue with Markovian arrival process and phase type services is studied. Efficient algorithm for computing the probability distribution and [...]![]()
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Two-dimensional continuous-time Markov chains (CTMCs) are useful tools for studying stochastic models such as queueing, inventory, and production systems. Of particular interest in this paper is the distribution of the maximal level visited in a[...]![]()
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This paper deals with the maximum number of customers in orbit (and in the system) during a busy period for the M/M/c retrial queue. Determining the distribution for the maximum number of customers in orbit is reduced to computation of certain a[...]![]()
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In this paper we deal with the main multiserver retrialqueue of M/M/c type with exponential repeated attempts. This model is known to be analytically intractable due to the spatial heterogeneity of the underlying Markov chain, caused by the retr[...]![]()
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We consider an M/G/1 queue with repeated attempts in which the server operates under a general exhaustive service vacation policy. We develop a comprehensive analysis of the system including ergodicity, limiting behaviour, stochastic decompositi[...]![]()
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This paper deals with a service system in which the processor must serve two types of impatient units. In the case of blocking, the first type units leave the system whereas the second type units enter a pool and wait to be processed later. We d[...]![]()
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Negative arrivals are used as a control mechanism in many telecommunication and computer networks. In the paper we analyze multiserver retrial queues; i.e., any customer finding all servers busy upon arrival must leave the service area and re-ap[...]![]()
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This paper deals with the analysis of an M/M/c queueing system with setup times. This queueing model captures the major characteristics of phenomena occurring in production when the system consists in a set of machines monitored by a single oper[...]![]()
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We consider multiserver retrial queues in which the time between two successive repeated attempts is independent of the number of customers applying for service. We study a Markovian model where each arriving customer finding any free server eit[...]![]()
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A stochastic clearing system is characterized by the existence of an output mechanism that instantaneously clears the system, i.e. removes all work currently present. In this paper we study the stochastic behavior of a single server clearing que[...]![]()
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This paper presents an algorithmic analysis of the busy period for the M/M/c queueing system. By setting the busy period equal to the time interval during which at least one server is busy, we develop a first step analysis which gives the Laplac[...]![]()
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This paper deals with the distribution of the maximum queue length in two-dimensional Markov models. In this framework, two typical assumptions are: (1) the stationary regime, and (2) the system homogeneity (i.e., homogeneity of the underlying i[...]![]()
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Queueing models including the effects of repeated attempts have wide practical use in designing communication systems. The model studied in this paper not only takes into account retrials due to congestion but also considers the effects of balki[...]![]()
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Many of the Currently used cellular networks have been constructed on the premise trial me retrial phenomenon is negligible and the operating environment is static. However. a proper modeling of the mobile cellular network cannot ignore the exis[...]![]()
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New developments in mobile communication technology lead to substantial increases in the retrial phenomenon and its effect on the quality of service (QoS). One aspect of this problem is considered in this paper, where we investigate the distribu[...]![]()
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We consider a multi-server retrial queueing model in which arrivals occur according to a Markovian arrival process. Using continuous-time Markov chain with absorbing states, we determine the distribution of the maximum number of customers in a r[...]![]()
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This paper analyses adiscrete-timeGeo/G/1retrialqueue with batch arrivals in which individual arriving customers have acontrol of admission. We study the underlying Markov chain at the epochs immediately after the slot boundaries making emphasis[...]![]()
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In this paper, information theoretic methodology for system modeling is applied to investigate the probability density function of the busy period in M/G/1 vacation models operating under the N-, T- and D-policies. The information about the dens[...]![]()
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Artalejo, Jesús R. ; Economou, A. ; Lopez-Herrero, M. J. | Amer Inst Mathematical Sciences | 2007-11Populations are often subject to the effect of catastrophic events that cause mass removal. In particular, metapopulation models, epidemics, and migratory flows provide practical examples of populations subject to disasters (e.g., habitat destru[...]![]()
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In this paper we study the M/H2/1 queue with returning customers. We obtain explicit formulae for the steady-state distribution and the expected quality characteristics of the system. In addition, a simple recursion scheme for computing the 'orb[...]![]()
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This paper deals with a single-server retrial queue with a finite number of sources. Our analysis extends previous work on this topic and includes the analysis of the arriving customer's distribution, the busy period and the waiting time process[...]![]()
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G-networks (or queueingnetworks with negative customers, signals, triggers, etc.) are characterized by the following feature: in contrast with the normal positive customers, negative customers arriving to a non-empty queue remove an amount of wo[...]![]()
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We consider the stochastic behaviour of a Markovian bivariate process {(C(t), N(t)), t greater than or equal to 0} whose state-space is a semi-strip S = {0, 1} x N. The intensity matrix of the process is taken to get a limit distribution P-ij = [...]![]()
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In this paper, information theoretic inference methodology for system modeling is applied to estimate the stationary distribution for the number of customers in single server queueing systems with service capacity utilized by a finite population[...]![]()
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In this paper we present information theoretic approximations for theM/G/1 queue with retrials. Various approximations for this model are obtained according to the available information about the service time probability density and the steady-s[...]![]()
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We consider a multiserver queueing system where customers may become impatient and then retry for service after some random time. The study of this queueing model is motivated by the existence of exchange distributed operating systems with a tim[...]![]()
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Artalejo, Jesús R. ; Gómez-Corral, Antonio ; Qi-Ming, He | Institut d'Estadística de Catalunya (Idescat) | 2010-07This paper aims to provide a comprehensive review on Markovian arrival processes (MAPs), which constitute a rich class of point processes used extensively in stochastic modelling. Our starting point is the versatile process introduced by Neuts ([...]![]()
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We study Markovian queueing systems in which the service rate varies whenever the queue length changes. More specifically we consider controllable queues operating under the so-called hysteretic policy which provides a rather versatile class of [...]![]()
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In this paper, we first consider single server retrial queues with two way communication. Ingoing calls arrive at the server according to a Poisson process. Service times of these calls follow an exponential distribution. If the server is idle, [...]![]()
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Mean value analysis is an elegant tool for determining mean performance measures in queueing models. In this paper we show how mean value analysis can be applied to retrial queues. First, we illustrate the technique for the standard M/G/1 retria[...]![]()
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The aim of this paper is to contribute to the connection between computer viruses spreading and epidemiological models. To this end, the block-structured state-dependent event (BSDE) approach is used to study the number of cases of infection in [...]![]()
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Artalejo, Jesús R. ; Gómez-Corral, Antonio | IEEE-Inst Electrical Electronics Engineers Inc | 2007-12The retrial phenomenon and its significant effect on network performance have been taking into account in the literature (e.g., random access protocols in computer networks, cellular mobile telephony). Most studies assume exponential distributio[...]![]()
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This paper deals with a multi-server retrial queueing model in which the number of active servers depends on the number of customers in the system. To this end, the servers are switched on and off according to a multithreshold strategy. For a fi[...]![]()
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We consider an M/G/1 retrial queue with finite capacity of the retrial group. We derive the Laplace transform of the busy period using the catastrophe method. This is the key point for the numerical inversion of the density function and the comp[...]![]()
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This note considers the N- and D-policies for the M/G/1queue. We concentrate on the true relationship between the optimal N- and D-policies when the cost function is based on the expected number of customers in the system.![]()
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This paper deals with a continuous review (s, S) inventory system where arriving demands finding the system out of stock, leave the service area and repeat their request after some random time. This assumption introduces a natural alternative to[...]![]()
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We are concerned with the main multiserver retrial queue of M/M/c type with exponential repeated attempts. It is known that an analytical solution of this queueing model is difficult and does not lead to numerical implementation. Based on approp[...]![]()
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There is a growing interest in queueing systems with negative arrivals; i.e. where the arrival of a negative customer has the effect of deleting some customer in the queue. Recently, Hanison and Pitel (1996) investigated the queue length distrib[...]![]()
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The M/G/1 queue with repeated attempts is considered. A customer who finds the server busy, leaves the service area and joins a pool of unsatisfied customers. Each customer in the pool repeats his demand after a random amount of time until he fi[...]![]()
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We consider queuing systems where customers are not allowed to queue, instead of that they make repeated attempts, or retrials, in order to enter service after some time. We obtain the distribution of the number of retrials produced by a tagged [...]![]()
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This paper deals with the main retrial queue of M/M/c-type with exponential repeated attempts. We refer to a busy period and present a detailed computational analysis of four new performance measures: (i) the successful retrials, (ii) the blocke[...]![]()
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The basic reproduction number, R (0), is probably the most important quantity in epidemiology. It is used to measure the transmission potential during the initial phase of an epidemic. In this paper, we are specifically concerned with the quanti[...]![]()
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This paper deals with a Markovian multiserver model, where the simultaneous effect of customerbalking, impatience and retrials is evaluated. The study of systems incorporating these features is motivated by the observation of real service system[...]![]()
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This paper deals with the M/G/1queue with D-policy, i.e., the server is turned off at the end of a busy period and turned on when the cumulative amount of work firstly exceeds some fixed value D. We first concentrate on the computation of the st[...]![]()
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The basic models of infectious disease dynamics (the SIS and SIR models) are considered. Particular attention is paid to the number of infected individuals that recovered and its relationship with the final epidemic size. We investigate this des[...]![]()
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In teletraffic applications of retrial queues only the service zone is observable. Another part of a retrial queue, the orbit, which represents the delay before repeated attempts to get service, cannot be observed. Thus, it is very important to [...]![]()
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This paper deals with a single server retrial queueing system subject to active and independent breakdowns. The objective is to extend the results given independently by Aissani [1] and Kulkarni and Choi [15]. To this end, we introduce the conce[...]![]()
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We are concerned with the M/G/1 retrial queue with balking. The ergodicity condition is first investigated making use Of classical mean drift criteria. The limiting distribution of the number of customers in the system is determined with the hel[...]![]()
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This note provides a unified approach to the distribution of the time to extinction from quasi-stationarity for general Markov chains evolving both in discrete and in continuous time. Our results generalize a number of similar derivations which [...]![]()
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Multi-server retrial queues are widely used to model stochastically many telephone systems and computer networks. This paper studies the distribution of the time needed to reach a certain level of congestion, i.e., a given number of customers in[...]![]()
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We consider a Markov decision process for an MX/M/1 queue that is controlled by batches of negative customers. More specifically, we derive conditions that imply threshold-type optimal policies, under either the total discounted cost criterion o[...]![]()
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Discrete-time multiserver queues have been used for many years to investigate the behavior of communication and computer systems in which time is slotted. In this paper, we consider the discrete-time Geo/Geo/cqueue. We first develop an efficient[...]![]()
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Performance Analysis of a Block-Structured Discrete-Time Retrial Queue with State-Dependent Arrivals
In this paper, we introduce a new discrete block state-dependent arrival (D-BSDA) distribution which provides fresh insights leading to a successful generalization of the discrete-time Markovian arrival process (D-MAP). The D-BSDA distribution i[...]![]()
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This paper is concerned with the performance evaluation of a single-server queue with repeated attempts and disasters. Our queueing system is characterized by the phenomenon that a customer who finds the server busy upon arrival joins a group of[...]![]()
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Many stochastic systems, including biological applications, use Markov chains in which there is a set of absorbing states. It is then needed to consider analogs of the stationary distribution of an irreducible chain. In this context, quasi-stati[...]![]()
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We consider a queueing system where a customer who finds all channels busy must decide either to join the queue or to retry after an exponentially distributed time. The performance of the system can be approximated by using the RTA approximation[...]![]()
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We are concerned with the M/G/1 queue with repeated attempts where a customer who finds the server busy leaves the service area and repeats his request after a random amount of time. We concentrate on the study of the waiting time process. Its a[...]![]()
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In this paper, we deal with a discrete-time multiserver retrial queue with finite population. Firstly, we study the Markov chain at the epochs immediately after slot boundaries making emphasis on the computation of its steady-state distribution.[...]![]()
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The main aim of this paper is to study the steady state behavior of an M/G/1-type retrial queue in which there are two flows of arrivals namely ingoing calls made by regular customers and outgoing calls made by the server when it is idle. We car[...]![]()
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This paper deals with the M/G/1 queue with N-policy. We show some applications of the stochastic decomposition property for the queue size. A new stochastic decomposition property for the waiting time is observed. Explicit expressions for the mo[...]![]()
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In this paper, we introduce a versatile block-structured state-dependent event (BSDE) approach that provides a methodological tool to construct non-homogeneous Markov-modulated stochastic models. Alternatively, the BSDE approach can be used to c[...]![]()
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We consider a retrial queueing system where customers at the retrial group have preemptive priority over customers at the waiting line. The stationary distribution can be approximated at a desired level of accuracy in such a way that the approxi[...]![]()
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Queueing systems with repeated requests have many useful applications in communications and computer systems modeling. In the majority of previous work the repeat requests are made individually by each unsatisfied customer. However, there is in [...]![]()
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This paper is concerned with the stochastic analysis of the departure and quasi-input processes of a Markovian single-server queue with negative exponential arrivals and repeated attempts. Our queueing system is characterized by the phenomenon t[...]![]()
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The population of naive T cells in the periphery is best described by determining both its T cell receptor diversity, or number of clonotypes, and the sizes of its clonal subsets. In this paper, we make use of a previously introduced mathematica[...]![]()
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We deal with stochastic epidemic models having a set of absorbing states. The aim of the paper is to study some continuous characteristics of the epidemic. In this sense, we first extend the classical study of the length of an outbreak by invest[...]![]()
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We investigate stochastic and epidemic models, when there is a random environment that influences the spread of the infectious disease. The inclusion of an external environment into the epidemic model is done by replacing the constant transmissi[...]![]()
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Modeling and understanding virus spreading is a crucial issue in computer security. Epidemiological models have been proposed to deal with this problem. We investigate the dynamics of computer virus spreading by considering an stochastic suscept[...]![]()
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We concentrate on the analysis of the busy period and the waiting time distribution of a multi-server retrial queue in which primary arrivals occur according to a Markovian arrival process (MAP). Since the study of a model with an infinite retri[...]![]()
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We consider queuing systems where customers are not allowed to queue; instead of that they make repeated attempts, or retrials, in order to enter service after some time. The performance of telephone systems and communication networks modelled a[...]![]()
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We study the maximumn umber of infected individuals observed during an epidemic for a Susceptible–Infected–Susceptible (SIS) model which corresponds to a birth–death process with an absorbing state. We develop computational schemes for the corre[...]![]()
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We study the maximumn umber of infected individuals observed during an epidemic for a Susceptible–Infected–Susceptible (SIS) model which corresponds to a birth–death process with an absorbing state. We develop computational schemes for the corre[...]![]()
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We analyze the dynamics of infectious disease spread by formulating the maximum entropy (ME) solutions of the susceptible-infected-susceptible (SIS) and the susceptible-infected-removed (SIR) stochastic models. Several scenarios providing helpfu[...]![]()
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The phenomenon of repeated attempts arises naturally in telecommunication and computer networks. One aspect of the retrial feature is considered in this paper, where we investigate the transient behavior of the successful and blocked events made[...]![]()
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We consider an M/G/1 retrial queue with finite capacity of the retrial group. First, we obtain equations governing the dynamic of the waiting time. Then, we focus on the numerical inversion of the density function and the computation of moments.[...]