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In order to do that, we use a stochastic fluid-flow model with two buffers, one for the agent that runs the routine tasks and the other for the remaining non-routine jobs at the CPU. ... We use the QoS performance measures to formulate and solve an optimization problem to design an optimal threshold value. ... The authors thank the editor and the anonymous reviewers for their comments and suggestions that led to considerable improvements in the content and presentation of this paper. ...doi:10.1016/j.peva.2004.06.002 fatcat:pk5splf4mvbhnm7gcmhegajzdq
This model can be formulated as a Markov Decision Process (MDP) for which the optimal strategy has nice structural properties. ... The fluid approach provides excellent approximations, and thus understanding, of the optimal MDP policy. ... In the next section we will exploit this description to determine a switching curve k(·) that approximates the optimal switching curve. x 1 (t) = λ − b(k Fluid-based approximations of the optimal policy ...doi:10.1007/s11134-017-9554-x fatcat:ka6n7trsjnb7nex6hip7gnzexi
The authors consider a model with two queues served by a sin- gle server with switch-over times. The server operates under a Bernoulli-threshold schedule. ... Summary: “We focus on window flow control as used in packet- switched communication networks. ...
Optimizing the "drain time" under a fluid scaling gives a simple linear switching strategy, which turns out to accurately approximate the numerically found optimal strategy in the stochastic model when ... For example, when µ1, µ2 ≥ µ0, the switching curves in the fluid model are both equal to zero, and hence the fluid policy gives preemptive priority to classes 1 and 2. ...doi:10.1145/1328690.1328711 fatcat:5l2ugws27bg2zakw4ounawuche
Acknowledgment The authors are grateful to Sem Borst for valuable discussions and comments. References ... The optimal switching curves in the fluid regime can be used to determine asymptotically fluid optimal strategies for the stochastic model. ... In Section 4.1 we determined the optimal trajectory for the fluid control model, n * (t). ...doi:10.1007/s11134-010-9171-4 fatcat:iuyjao36fffzlci5b5ldc5pb7y
The author then studies the correspondences between the stochastic network problems with an associated fluid problem, proving that the value function of the fluid problem provides a lower bound for the ... control of queueing networks: an approach via fluid models. ...
Moreover, we find that intuitive switching strategies that are optimal for queues with homogeneous entry rates are not optimal in this setting. ... We use approximate dynamic programming methods to determine when servers should be switched, and we compare the performance of such dynamic allocations to that of a pre-scheduled deterministic allocation ... We now present our optimization models for this problem. ...doi:10.1080/0740817x.2011.564602 fatcat:4c2r6ghv2nayfgjrdgd7qagk2y
lengths crosses an activation threshold (with ratio and activation threshold parameters for each direction). ... The target ratio is chosen to be optimal in a deterministic fluid approximation, assuming a convex holding cost is incurred on the two queues during the overload incident. ... The stochastic AP determines when SSC occurs, and how the fluid evolves during periods of SSC; see §5.3 below. Time-Varying Models. ...doi:10.1287/ijoc.2015.0642 fatcat:yrtxa2pombb2jhrp5m7glud47i
We survey both the different applications areas in communication networks as well as the theoretical tools that have been developed to model and to solve the resulting control problems. ... Another example of this approach is the reference  where the authors consider a fluid model for the optimal flow control. ... and of a stochastic fluid, respectively. ...doi:10.1007/978-1-4615-0805-2_16 fatcat:wwfp5ccqfng7dghdpffcfnfzsa
A fluid approximation gives the main term in the asymptotic expression of the value function for a controllable stochastic network. ... Key words and phrases. stochastic network, fluid optimal control problem, asymptotic optimality, large deviations. ... Acknowledgement The authors would like to thank an anonymous referee for his valuable remarks that have improved the paper. ...doi:10.1214/aoap/1069786504 fatcat:jlovjpl5jbhuroblhmx6cdf4pu
Run-time Models for Self-managing Systems and Applications
Our primary focus is on multiserver systems in general, since this research provides the mathematical methods and results that have been and will continue to be used for the stochastic analysis and/or ... Motivated by emerging trends and applications such as autonomic computing, this paper presents an overview of some research in the stochastic analysis and optimization of multiserver systems. ... He also thanks Alan Hoffman, Yingdong Lu, Baruch Schieber, Mayank Sharma and Shmuel Winograd for helpful comments on an earlier version of the paper, as well as Dan Prener for fruitful discussions regarding ...doi:10.1007/978-3-0346-0433-8_1 fatcat:7ddyzwfwebhfrdkb5in4ylkcee
To gain fundamental insights into these very difficult problems, we consider a fluid model of n × n input-queued switches with associated fluid-flow costs, and we derive an optimal scheduling control policy ... Computational experiments demonstrate the benefits of our optimal scheduling policy over variants of max-weight scheduling within fluid models of input-queued switches. ... Fluid Models is section introduces a deterministic process that represents our uid models for input-queued switches, describes the scaled processes of the original stochastic process, and relates them ...arXiv:1910.13657v2 fatcat:5am3gattt5cg3fuwrnl5tfrvsa
This paper uses stochastic fluid models (SFMs) for control and optimization (rather than performance analysis) of communication networks, focusing on problems of buffer control. ... Index Terms-Communication network, perturbation analysis, stochastic fluid network. ... The fluid-flow worldview can provide either approximations to queuing-based models or primary models in their own right. ...doi:10.1109/tac.2002.800739 fatcat:erx2u5fcjvagfct5n6kwy6prfe
Encyclopedia of Operations Research and Management Science
The underlying model for an ATM reference connection consists of a network with a sequence of */D/1/N 5 queues and an extra delay (propagation and switching) between these queues. ... Examples are given for the loss probability of ATM cells in G/G/1/N 4 type systems as well as certain tandem networks that represent a model for ATM reference connections. ... Several approaches have been used for modeling network traffic sources, including fluid-flow sources  , on-off sources  , MPEG coded video sources  , Composite Source Models  , ...doi:10.1007/978-1-4419-1153-7_1188 fatcat:qc4mcfmojvesvdeee7mzrhtxby
In a number of these cases, the thresholds that optimize performance measures such as overall average sojourn time are determined.” 2001¢:60194 60K25 90B22 Dudin, Alexander [Dudin, Aleksandr] (BE-BEL-AMI ... Summary: “A second-order fluid flow model of a queue with finite capacity buffer and variable net input process is presented, based on the previous work of R. L. Karandikar and V. G. Kulkarni. ...
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