The component queues method for QBD process fitting and analysis
File(s)
Accepted version
Author(s)
Bor, Julianna
Casale, Giuliano
Smirni, Evgenia
Type
Conference Paper
Abstract
Markovian queueing analysis requires fitting models of arrival and service processes, such as phase-type (PH) distributions, to accurately represent system measurements. However, fitting real-world data is challenging in practice due to model over-parameterization, the large order of the fitting equations, and the limited understanding of the impact of fitting decision on queueing. Motivated by these issues, we present a methodology that uses quasi-birth-death (QBD) processes to fit PH distributions directly from measured queueing data. Core to the proposed method is a new result that reduces the solution of a broad class of QBD processes to the analysis of a collection of simpler queueing systems featuring PH distributions of small order, leading to exact or approximate solutions depending on the chosen arrival process. The proposed method reduces the computational complexity of solving a QBD process from cubic to quadratic for this special class of QBD processes. Numerical results on real traces demonstrate that this feature enables accurate PH fitting from real-world system data.
Date Acceptance
2026-06-06
Citation
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN
0302-9743
Publisher
Springer
Journal / Book Title
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Copyright Statement
Subject to copyright. This paper is embargoed until publication. Once published the author’s accepted manuscript will be made available under a CC-BY License in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy).
License URL
Source
QEST+FORMATS 2026
Publication Status
Accepted
Start Date
2026-09-02
Finish Date
2026-09-04
Coverage Spatial
Liverpool, UK