Papers in International Journals

• Ferreira, Fátima; Pacheco, António; Ribeiro, Helena (2021)  Distribution of the number of losses in busy-periods of oscillating M-X/G/1/(n,a,b) systems . Computers & Operations Research: 129, 105180.

• Ferreira, Fátima; Pacheco, António; Ribeiro, Helena (2017)  Moments of losses during busy-periods of regular and nonpreemptive oscillating MX/G/1/n systems . Annals of Operations Research: 252(1), 191–211.

• Pacheco, António; Ribeiro, Helena (2008)  Moments of the duration of busy periods of M^X/G/1/n systems . Probability in the Engineering and Informational Sciences: 22(3), 347-354.

• Pacheco, António; Ribeiro, Helena (2008)  Consecutive customer losses in oscillating GI^(X)/M//n systems with state dependent services rates . Annals of Operations Research: 162(1), 143-158.

• Pacheco, António; Ribeiro, Helena (2008)  Consecutive customer losses in regular and oscillating M^X/G/1/n systems . Queueing Systems. Theory and Applications.: 58(2), 121-136.

Papers or Chapters in Edited Books

• Ferreira, Fátima; Pacheco, António; Ribeiro, Helena (2020)  Numbers of Served and Lost Customers in Busy-Periods of M/M/1/n Systems with Balking . Lecture Notes in Computer Science: 12251, 147-156.

• Ferreira, Fátima; Pacheco, António; Ribeiro, Helena (2016)  On the blocking probability and loss rates in nonpreemptive oscillating queueing systems . Lecture Notes in Computer Science, Springer, Cham: 9845, 155-166.

• Ferreira, Fátima; Pacheco, António; Ribeiro, Helena (2013)  Distribution of the number of losses in busy-periods of M^X/G/1/n Systems . Advances in Regression, Survival Analysis, Extreme Values, Markov Processes and Other Statistical Applications, Springer Berlin Heidelberg, 163-171.

• Pacheco, António; Ribeiro, Helena (2009)  Momentos do número de perdas de clientes em períodos de ocupação contínua de sistemas oscilantes M/G/1/n (Moments of the number of losses in busy periods of finite oscillating M/G/1/n queueing systems) . Estatística. Arte de Explicar o Acaso, Edições SPE, Lisboa, 497-510.

• Ferreira, Fátima; Pacheco, António; Ribeiro, Helena (2009)  Analysis of finite oscillating GI^X/M(m)//N queueing systems . Recent Advances in Stochastic Operations Research, World Scientific, Singapore, 79-98.

• Ferreira, Fátima; Pacheco, António; Ribeiro, Helena (2009)  Análise de sistemas oscilantes M^X/G/1/(n,a,b) . Estatística. Arte de Explicar o Acaso, Edições SPE, Lisboa, 233-244.

• Pacheco, António; Ribeiro, Helena (2007)  Bursts and gaps of Markov renewal arrival processes . Recent Advances in Stochastic Operations Research, World Scientific, Singapore, 245-262.

• Pacheco, António; Ribeiro, Helena (2006)  Sucessões markovianas com recompensas e visitas a conjuntos de estados em processos semi-markovianos (Markov-reward sequences and visits to sets of states in semi-Markov processes) . In L. Canto e Castro, E.G. Martins, C. Rocha, M.F. Oliveira, M.M. Leal, and F. Rosado, editors, Ciência Estatística: Edições SPE, Lisboa, 545-557.

• Pacheco, António; Ribeiro, Helena (2005)  Visitas a conjuntos de estados em processos semi-markovianos (Visits to set of states in semi-Markov processes) . In C.A. Braumann, P. Infante, M.M. Oliveira, R. Alpizar-Jara, and F. Rosado, editors, Estatística Jubilar: Edições SPE, Lisboa, 537-548.

Communications in Conference Proceedings

• Ferreira, Fátima; Pacheco, António; Ribeiro, Helena (2007)  Markov regenerative analysis of finite oscillating queueing systems . Procs. of the International Workshop on Recent Advances in Stochastic Operations Research - RASOR 2007, Nanzan University: Japan, March 5-6, 235-242.

• Pacheco, António; Ribeiro, Helena (2007)  Algorithmic approach to compute moments of the duration of busy periods in oscillating queueing systems . Procs. of the International Workshop on Recent Advances in Stochastic Operations Research - RASOR 2007, Nanzan University: Japan, March 5-6, 235-242.

• Pacheco, António; Ribeiro, Helena (2006)  Consecutive customer loss probabilities in M/G/1/n and GI/M(m)/n systems . Procs. SMCTools - Tools for Solving Structured Markov Chains: Pisa, Italy, October 10.

• Pacheco, António; Ribeiro, Helena (2006)  Algorithms for computing moments of the length of busy-periods of single-server systems . Proceedings of the 10th WSEAS International Conference on COMPUTERS, Vouliagmeni, Athens, Greece, July 13-15, 986-991.

• Ribeiro, Helena; Pacheco, António (2005)  Bursts and gaps of Markov renewal arrival processes . Procs. International Workshop on Recent Advances in Stochastic Operations Research - RASOR 2005, Canmore: Canada, August 25-26, 211-218.

Thesis

• Ribeiro, Helena (2007)  Customer Loss Probabilities and other Performance Measures of Regular and Oscillating Systems . Instituto Superior Técnico - UTL, Lisboa.

• Ribeiro, Helena (1995)  Filas de Espera: Estudo Teórico e Simulaçãao de Alguns Modelos (Queueing Systems: Study and Simulation of Some Models) . Faculdade de Ciências, Universidade de Lisboa, Lisboa.