Members > Faculty Members

Helena Ribeiro

Institutional Address

Instituto Politécnico de Leiria
Escola Superior de Tecnologia e Gestão (ESTG)
Campus 2
Morro do Lena - Alto do Vieiro
Apartado 4163
2411 - 901 LEIRIA


Phone: | Email: helena.ribeiro@ipleiria.pt

Position

Coordinator Professor, Instituto Politécnico de Leiria

Area

Statistics and Stochastic Processes

Principal Area

Queueing Theory

Qualifications

  •  Ph.D. in Mathematics, IST, UTL, 2007
  • M.Sc. in Probability and Statistics, FCUL, UL, 1995


Publications

Papers in International Journals

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 (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.