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Scheduling Approach (scheduling + approach)
Selected AbstractsResource allocation with minimum rates for OFDM broadcast channels,EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2007Carolin Huppert Downlink transmissions with minimum rate requirements over orthogonal frequency division multiplexing (OFDM) channels are commonly done by means of scheduling algorithms. However, regarding it from an information theoretical point of view, this is not optimal since broadcast techniques can achieve higher rates. The drawbacks of the optimum broadcast algorithm are that the signalling overhead is larger than for scheduling and also the computational complexity is much higher. In this paper we propose an algorithm which overcomes these points. This algorithm is a hybrid algorithm combining scheduling and broadcast approaches. Thus, it combines advantages of both methods. Furthermore, we present modifications to this algorithm to avoid irresolvable decoding dependencies. We show by means of simulation results that the proposed algorithm operates close to the optimum performance and that it outperforms a pure scheduling approach. Copyright © 2007 John Wiley & Sons, Ltd. [source] Class-based weighted fair queueing: validation and comparison by trace-driven simulationINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2005Rachid El Abdouni Khayari Abstract World-wide web as well as proxy servers rely for their scheduling on services provided by the underlying operating system. In practice, this means that some form of first-come-first-served (FCFS) scheduling is utilized. Although FCFS is a reasonable scheduling strategy for job sequences that do not show much variance, for the world-wide web it has been shown that the requested-object sizes do exhibit heavy tails. Under these circumstances, job scheduling on the basis of shortest-job first (SJF) or shortest remaining processing time (SRPT) has been shown to minimize the total average waiting time. However, these methods have the disadvantage of potential job starvation. In order to avoid the problems of both FCFS and SJF we present in this paper a new scheduling approach called class-based interleaving weighted fair queueing (CI-WFQ). This scheduling approach exploits the specific characteristics of the job stream being served, that is, the distribution of the sizes of the objects being requested, to set its parameters such that good mean response times are obtained and starvation does not occur. In that sense, the new scheduling strategy can be made adaptive to the characteristics of the job stream being served. In this paper we compare the new scheduling approach (using trace-driven simulations) to FCFS, SJF and the recently introduced ,-scheduling, and show that CI-WFQ combines very good performance (as far as mean and variance of response time and blocking probability are concerned) with a scheduling complexity almost as low as for FCFS (and hence, lower than for SJF and ,-scheduling). The use of trace-driven simulation is essential, since the special properties of the arrival process makes analytical solutions very difficult to achieve. Copyright © 2005 John Wiley & Sons, Ltd. [source] Robust global stabilization of linear systems with input saturation via gain schedulingINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 4 2010Bin Zhou Abstract The problem of robust global stabilization of linear systems subject to input saturation and input-additive uncertainties is revisited in this paper. By taking advantages of the recently developed parametric Lyapunov equation-based low gain feedback design method and an existing dynamic gain scheduling technique, a new gain scheduling controller is proposed to solve the problem. In comparison with the existing ,2 -type gain scheduling controller, which requires the online solution of a state-dependent nonlinear optimization problem and a state-dependent ,2 algebraic Riccati equation (ARE), all the parameters in the proposed controller are determined a priori. In the absence of the input-additive uncertainties, the proposed controller also partially recovers Teel's ,, -type scheduling approach by solving the problem of global stabilization of linear systems with actuator saturation. The ,, -type scheduling approach achieves robustness not only with non-input-additive uncertainties but also requires the closed-form solution to an ,, ARE. Thus, the proposed scheduling method also addresses the implementation issues of the ,, -type scheduling approach in the absence of non-input-additive uncertainties. Copyright © 2009 John Wiley & Sons, Ltd. [source] Real-time scheduling of multiple uncertain receding horizon control systemsOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 2 2009Behnood Gholami Abstract In this paper, a new scheduling approach is proposed that considers the effect of modeling uncertainty for multiple continuous time receding horizon control (RHC) systems. This is accomplished by combining a scheduling approach with results from the continuous time nonlinear systems theory. It is shown that using a rate monotonic priority assignment method combined with analytical bounds on the prediction error, the problem of scheduling multiple uncertain plants can be cast into an appropriate constrained optimization problem. The constraints guarantee that the processes will be schedulable. The optimization provides optimized performance and balanced resource allocation in the presence of uncertainty. The proposed method was applied to a real-time simulation of RHC trajectory tracking for two hovercraft vehicles demonstrating the validity of the approach. Copyright © 2008 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||