Control kernel based adaptive control implementation

[EN] A control system with distributed computing resources always should guarantee the safe control of the plant. In this contribution, the concept of control kernel is used for that purpose. Two types of nodes with different resources are defined: the powerful server node and the resource-constrained light node. This architecture allows to split the control tasks into two blocks. Those demanding strong computing resources are allocated in the server nodes and those compelling tasks required to ensure the safety of the controlled plant are allocated in the light nodes. Resource limitations lead to control adaptation. Two simple applications illustrate some of the benefits of this architecture with one server node and one light node, even the architecture can be extended to several nodes. In the first case, an adaptive control is implemented in the server node, providing the control algorithm to the light node, which is also able to compute a local safe control action. In the second experiment, two different control tasks requiring different resources are implemented in a mobile robot control. To keep bounded the computing time at the local level, the supervisor decides the time allocated to each activity, providing the resulting controller to the light node.This work has been partially granted by Conselleria de Educación Generalitat Valenciana, under PROMETEO project number 2008-088, and Ministerio de Ciencia e Innovaci´on under COBAMI project DPI2011-28507-C02-01/02.Simarro Fernández, R.; Albertos Pérez, P.; Simó Ten, JE. (2013). Control kernel based adaptive control implementation. SIGBED review. 10(1):24-28. doi:10.1145/2492385.2492389S242810

System Support for Bandwidth Management and Content Adaptation in Internet Applications

This paper describes the implementation and evaluation of an operating system module, the Congestion Manager (CM), which provides integrated network flow management and exports a convenient programming interface that allows applications to be notified of, and adapt to, changing network conditions. We describe the API by which applications interface with the CM, and the architectural considerations that factored into the design. To evaluate the architecture and API, we describe our implementations of TCP; a streaming layered audio/video application; and an interactive audio application using the CM, and show that they achieve adaptive behavior without incurring much end-system overhead. All flows including TCP benefit from the sharing of congestion information, and applications are able to incorporate new functionality such as congestion control and adaptive behavior.Comment: 14 pages, appeared in OSDI 200

Data reduction in the ITMS system through a data acquisition model with self-adaptive sampling rate

Long pulse or steady state operation of fusion experiments require data acquisition and processing systems that reduce the volume of data involved. The availability of self-adaptive sampling rate systems and the use of real-time lossless data compression techniques can help solve these problems. The former is important for continuous adaptation of sampling frequency for experimental requirements. The latter allows the maintenance of continuous digitization under limited memory conditions. This can be achieved by permanent transmission of compressed data to other systems. The compacted transfer ensures the use of minimum bandwidth. This paper presents an implementation based on intelligent test and measurement system (ITMS), a data acquisition system architecture with multiprocessing capabilities that permits it to adapt the system’s sampling frequency throughout the experiment. The sampling rate can be controlled depending on the experiment’s specific requirements by using an external dc voltage signal or by defining user events through software. The system takes advantage of the high processing capabilities of the ITMS platform to implement a data reduction mechanism based in lossless data compression algorithms which are themselves based in periodic deltas