Browsing by Author "Melchor-Aguilar, D."

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    Comparing PI controllers for delay models of TCP/AQM networks
    (Elsevier, 2010) Ünal H.U.; Melchor-Aguilar, D.; Üstebay, D.; Niculescu, S.-I.; Özbay, Hitay
    In this paper, ns-2 simulations and related comparisons of four different PI controllers designed for TCP/AQM networks will be presented. The simulations are performed for various scenarios. © 2010 IFAC.
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    Comparison of PI controllers designed for the delay model of TCP/AQM networks
    (Elsevier, 2013) Ünal H. U.; Melchor-Aguilar, D.; Üstebay, D.; Niculescu, S. -I.; Özbay, Hitay
    One of the major problems of communication networks is congestion. In order to address this problem in TCP/IP networks, Active Queue Management (AQM) scheme is recommended. AQM aims to minimize the congestion by regulating the average queue size at the routers. To improve upon AQM, recently, several feedback control approaches were proposed. Among these approaches, PI controllers are gaining attention because of their simplicity and ease of implementation. In this paper, by utilizing the fluid-flow model of TCP networks, we study the PI controllers designed for TCP/AQM. We compare these controllers by first analyzing their robustness and fragility. Then, we implement these controllers in ns-2 platform and conduct simulation experiments to compare their performances in terms of queue length. Taken together, our results provide a guideline for choosing a PI controller for AQM given specific performance requirements.