Hierarchical Real-time System Research Articles

Fault Tolerant Dynamic Scheduling on Real Time Hierarchical System: Proposals for Fault Tolerant Mechanism on Safety-Critical System

The paradigm changes from federated architecture to integrated architecture in the real time system introduces a partitioned system to ensure fault isolation and for scheduling the hierarchy scheduling at the global level between partition and local in partition. Integrated architecture based on partitioned system with hierarchical scheduling is referred as real time hierarchical system which is a solution to increase efficiency in terms of hardware cost and size. This approach increasing the complexity of the integration process including the handling of faults. In this paper the authors describe a proposal with three components for dealing with fault tolerant in real time hierarchical systems by handling fault in task level, partition level and distributed level. The contribution of this proposal is the mechanism for building fault tolerant system on real time hierarchical system.

Compositional real-time scheduling framework for periodic reward-based task model

As the size and complexity of embedded software systems increase, compositional real-time scheduling framework is widely accepted as means to build large and complex systems. A compositional real-time scheduling framework proposes to decompose a system into independent subsystems and provides ways to assemble them into a flexible hierarchical real-time scheduling system while guaranteeing the internal real-time requirements of each subsystem. In this paper, we consider the imprecise reward-based periodic task model in compositional scheduling framework. Thus, we introduce the imprecise periodic resource model to characterize the imprecise resource allocations provided by the system to a single component, and the interface model to abstract the imprecise real-time requirements of the component. The schedulability of mandatory parts is also analyzed to meet the minimum requirement of tasks. Finally, we provide a scheduling algorithm to guarantee a certain amount of reward, which makes it feasible to efficiently compose multiple imprecise components.

A motion control algorithm for a continuous mining machine based on a hierarchical Real-time Control System design methodology

The drive toward increased safety for coal miners has led to the development of computer-assisted methods of underground coal mining. The development of control architectures for the control of the movement of continuous mining machines (tramming control) is an important part of this overall effort. The tramming control algorithm design described is in concert with hierarchical architecture design principles developed at National Institute of Standards and Technology (NIST), referred to as the Real-time Control Systems (RCS) methodology. The algorithm design allows for the control of both cutting and free-space movement by a continuous mining machine and allows for a high degree of human operator interaction.

Software features of DBMS kernel in large real-time EMS systems

Improvements made to a relational database management system (DBMS) developed for real-time energy management and control systems for electric utilities are described. The focus is on the software performance improvement features and the dual database concept for coordinated updates. The discussion covers task structuring, buffer usage, active restructuring, and presolving of access routes. Some of these features are applicable to other real-time systems with large databases shared by many application programs. The extension of the DBMS design for use in a hierarchical real-time system is described. >

Structured hierarchical real-time operating system for a sequential process control

A multilevel hierarchical real-time operating system SPS for sequential process control is presented. This system has been realized to carry out the gas turbins tests in a production environment. The system has been built up using the “bottom up” principle in such a way that each level implements a higher level machine in terms of primitives offered at that level. In this paper the modular system representation is given as well as its functional representation. Both, modular and functional, system representation, are discused from the utilitary for designer and user point of view.

An APL shared variable processor in a distributed real-time environment

A hierarchical real-time computer system has been developed for laboratory automation purposes. It consists of microcomputers for data acquisition and control and a large mini for data processing. The control micros are connected to each other, the mini and an operator's terminal through a communication microprocessor. This latter is designed in accordance with the APL concept of Shared Variable Processor, taking into account the reliability and throughput considerations steming from the real-time and distributed nature of the system.

Structured Hierarchical Real-time Operating System for a Sequential Process Control

A multilevel hierarchical real-time operating system SPS for sequential process control is presented. This system has been realized to carry out the gas turbine tests in a production environment. The system has been built up using the “bottom up” principle in such a way that each level implements a higher level machine in terms of primitives offered at that level. In this paper the modular system representation is given as well as its functional representation. Both, modular and functional, system representation, are discused from the utilitary for designer and user point of view.

An APL Shared Variable Processor in a Distributed Real-time Environment

A hierarchical real-time computer system has been developed for laboratory automation purposes. It consists of microcomputers for data acquisition and control and a large mini for data processing. The control micros are connected to each other, the mini and an operator’s terminal through a communication microprocessor. This latter is designed in accordance with the APL concept of Shared Variable Processor, taking into account the reliability and throughput considerations steming from the real-time and distributed nature of the system.

An interactive language for computer-aided identification and control system design

A new interactive command language was developed to implement integrated computer-aided design in computer control applications. It is intended to operate at the supervisory level in a real-time hierarchical system. The integrated approach is based on convolution algebra and provides a unified conceptual framework for studying the behaviour of practical systems in the time domain. Consequently, as an alternative to choosing fixed system structures and design procedures, the user may evaluate experimental procedures suggested by the underlying theory. The language has been implemented on a minicomputer at Bradford University and applied to industrial control problems. The highly flexible and practical aspects of the language are demonstrated.

Hierarchical Automatic Control System for Chemical Plant

Principles of the construction of a hierarchical real-time control system for a large plant are discussed. As an example of the hierarchical automatic control system, a three-level control system for a large chemical complex is described.