2 research outputs found
Stochastig modeling with continuous feedback markov fluid queues
Cataloged from PDF version of article.Markov fluid queues (MFQ) are systems in which a continuous-time Markov chain
determines the net rate into (or out of ) a buffer. We deal with continuous feedback
MFQs (CFMFQ) for which the infinitesimal generator of the background process
and the drifts in each state are allowed to depend on the buffer level through continuous
functions. Explicit solutions of CFMFQs for a few special cases has been
reported, but usually numerical methods are preferred.
A numerically stable solution method based on ordered Schur decomposition
is already known for multi-regime MFQs (MRMFQ). We propose a framework for
approximating CFMFQs by MRMFQs via discretizing the buffer space. The parameters
of the CFMFQ are approximated by piecewise constant functions. Then, the
solution is obtained by block-tridiagonal LU decomposition for the related MRMFQ.
Moreover, we describe a numerical method that enables us to solve large scale systems
efficiently.
We model basically two different stochastic systems with CFMFQs. The first is
the workload-bounded MAP/PH/1 queue, to which the arrivals occur according to
a workload-dependent MAP (Markovian Arrival Process), and the arriving job size
distribution is phase-type. The jobs that would cause the buffer to overflow are rejected
partially or completely. Also, the service speed is allowed to depend on the
buffer level. As the second application, we model the horizon-based delayed reservation
mechanism in Optical Burst Switching networks with or without fiber delay
lines. We allow multiple traffic classes and the effect of offset-based and FDL-based
differentiation among traffic classes in terms of burst blocking is investigated.
Lastly, we propose a distributed algorithm for air-time fairness in multi-rate
WLANs that overcomes the performance anomaly in IEEE 802.11 WLANs. We also
give a stochastic model of the proposed model, and provide a novel and elaborate proof for its effectiveness. We also present an extensive simulation study.Yazıcı, Mehmet AkifPh.D
Reliability Abstracts and Technical Reviews January - December 1970
Reliability Abstracts and Technical Reviews is an abstract and critical analysis service covering published and report literature on reliability. The service is designed to provide information on theory and practice of reliability as applied to aerospace and an objective appraisal of the quality, significance, and applicability of the literature abstracted