Reliability Analysis of Safety Grade Programmable Logic Controller
This paper focuses on the random hardware failures necessary for the safety assessment of the reactor protection system (RPS). A prediction method of the hardware failure rate for safety assessment is suggested, and applied to the safety grade programmable logic controller (PLC) to identify design weak points from a safety point of view
Task Modeling for Energy Efficiency and Real Time Scheduling in Sensor Networks
We present task modeling methodology in sensor networks. In proposed model, tasks are classified according to the operating modes of related resources so that the operating current for each task can be easily derived. In addition, the execution time for a task is analyzed according to the task's characteristic based on given task classification. Consequently, the breakdown for energy consumption of each task is systematically extracted by multiplying achieved execution time, operating current, and fixed operating voltage. Such specifications acquired through our task modeling are useful to support energy efficient and real time task scheduling
The cyclic executive model and Ada
Periodic processes are major parts of many real-time embedded computer applications. The programming language Ada permits programming simple periodic processes, but it has some serious limitations; producing Ada programs with real-time performance comparable to those produced to date using traditional cyclic executives requires resorting to techniques that are specific to one machine or compiler. We present and evaluate the cyclic executive model for controlling periodic processes. The features and limitations of Ada for programming cyclic executive software are discussed and demonstrated, and some practical techniques for circumventing Ada limitations are described.