Flexible Workload Research Articles

QoC elastic scheduling for real-time control systems

The elastic task model, a significant development in scheduling of real-time control tasks, provides a mechanism for flexible workload management in uncertain environments. It tells how to adjust the control periods to fulfill the workload constraints. However, it is not directly linked to the quality-of-control (QoC) management, the ultimate goal of a control system. As a result, it does not tell how to make the best use of the system resources to maximize the QoC improvement. To fill in this gap, a new feedback scheduling framework, which we refer to as QoC elastic scheduling, is developed in this paper for real-time process control systems. It addresses the QoC directly through embedding both the QoC management and workload adaptation into a constrained optimization problem. The resulting solution for period adjustment is in a closed-form expressed in QoC measurements, enabling closed-loop feedback of the QoC to the task scheduler. Whenever the QoC elastic scheduler is activated, it improves the QoC the most while still meeting the system constraints. Examples are given to demonstrate the effectiveness of the QoC elastic scheduling.

Feedback scheduling of model-based networked control systems with flexible workload

In this paper, a novel control structure called feedback scheduling of model-based networked control systems is proposed to cope with a flexible network load and resource constraints. The state update time is adjusted according to the real-time network congestion situation. State observer is used under the situation where the state of the controlled plant could not be acquired. The stability criterion of the proposed structure is proved with time-varying state update time. On the basis of the stability of the novel system structure, the compromise between the control performance and the network utilization is realized by using feedback scheduler. Examples are provided to show the advantage of the proposed control structure.

Elastic scheduling for flexible workload management

An increasing number of real-time applications related to multimedia and adaptive control systems require greater flexibility than classical real-time theory usually permits. We present a novel scheduling framework in which tasks are treated as springs with given elastic coefficients to better conform to the actual load conditions. Under this model, periodic tasks can intentionally change their execution rate to provide different quality of service and the other tasks can automatically adapt their periods to keep the system underloaded. The proposed model can also be used to handle overload conditions in a more flexible way and to provide a simple and efficient mechanism for controlling a system's performance as a function of the current load.

Cybernetic institutional management theory and practice: A system of flexible workload for university teachers

Cybernetic institutional management theory and practice: A system of flexible workload for university teachers

Cybernetic institutional management theory and practice: A system of flexible workload for university teachers

Cybernetic institutional management theory and practice: A system of flexible workload for university teachers

Fawsim

This paper describes a flexible artificial workload simulator in use both as a pedagogic aid in a teaching environment and as a tool in a software prototype test facility. The background motivations behind the development of the tool are presented first. This is followed by a delineation of the goals derived from the motivations and examination of related work. Next the design choices are pre sented and justified. This is followed by a brief description of the tool. The presenta tion continues with a description of the choices made during the implementation phase. Particular attention is paid to how the sequencing of workload components was achieved. The discussion of implemen tation is concluded with some necessary low level details. The validation pro cedures are described. Finally the opera tion of the tool is explained and conclu sions are given.