8 research outputs found
Modelling TCP congestion control dynamics in drop-tail environments
In this paper we study communication networks that employ drop-tail queueing and additive-increase multiplicative-decrease (AIMD)
congestion control algorithms. We show that the theory of non-negative matrices may be employed to model such networks and to derive basic
theorems concerning their behaviour
Asymptotic Approximations for TCP Compound
In this paper, we derive an approximation for throughput of TCP Compound
connections under random losses. Throughput expressions for TCP Compound under
a deterministic loss model exist in the literature. These are obtained assuming
the window sizes are continuous, i.e., a fluid behaviour is assumed. We
validate this model theoretically. We show that under the deterministic loss
model, the TCP window evolution for TCP Compound is periodic and is independent
of the initial window size. We then consider the case when packets are lost
randomly and independently of each other. We discuss Markov chain models to
analyze performance of TCP in this scenario. We use insights from the
deterministic loss model to get an appropriate scaling for the window size
process and show that these scaled processes, indexed by p, the packet error
rate, converge to a limit Markov chain process as p goes to 0. We show the
existence and uniqueness of the stationary distribution for this limit process.
Using the stationary distribution for the limit process, we obtain
approximations for throughput, under random losses, for TCP Compound when
packet error rates are small. We compare our results with ns2 simulations which
show a good match.Comment: Longer version for NCC 201
Modelling TCP congestion control dynamics in drop-tail environments
In this paper we study communication networks that employ drop-tail queueing and additive-increase multiplicative-decrease (AIMD)
congestion control algorithms. We show that the theory of non-negative matrices may be employed to model such networks and to derive basic
theorems concerning their behaviour
Modelling TCP congestion control dynamics in drop-tail environments
In this paper we study communication networks that employ drop-tail queueing and additive-increase multiplicative-decrease (AIMD)
congestion control algorithms. We show that the theory of non-negative matrices may be employed to model such networks and to derive basic
theorems concerning their behaviour
Modelling TCP congestion control dynamics in drop-tail environments
In this paper we study communication networks that employ drop-tail queueing and additive-increase multiplicative-decrease (AIMD)
congestion control algorithms. We show that the theory of non-negative matrices may be employed to model such networks and to derive basic
theorems concerning their behaviour
Robust stabilization and observation of positive Takagi-Sugeno systems
Esta tesis propone metodologías para diseñar controladores robustos y observadores para los sistemas positivos descritos por modelos de Takagi-Sugeno (TS), lineal, inciertos, y tal vez con retraso. Las condiciones de síntesis se expresan como LMIs (desigualdades matriciales lineales).
En la primera parte, se establecen las condiciones para garantizar la estabilización asintótica y la α-estabilización de los sistemas T-S lineales positivas y, tal vez afectados por incertidumbres de intervalo, usando controladores de retroalimentación de estado descompuestos.
En la segunda parte, se dan las condiciones necesarias y suficientes para la estabilización de los sistemas de T-S positivos con retraso, en dos casos: cuando las variables de premisa del sistema son medibles o no. Además, el problema de diseño de control basado en observador es considerado, por las leyes de retroalimentación del estado que se pueden elegir con o sin memoria.
Para mostrar la eficacia de los métodos propuestos, se proporcionan ejemplos numéricos y prácticos, dando resultados satisfactorios.Departamento de Ingeniería de Sistemas y Proceso