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
A Prototype Embedded XML-DA Server and its Evaluations
In current control systems, it is important to get information from field devices just when the information is needed for applications such as maintenance, asset management or diagnosis. However, getting information for those applications is not always easy. Many control systems do not provide enough information for those purposes, because they are designed for its own purpose: to control the plant. Since the devices themselves possess the necessary information, it is desirable for such applications to have direct access via open and standard interfaces. It is shown that an OPC XML-DA (XML data access) server embedded in the device is a possible candidate for this objective. We have developed a prototype server on a small embedded controller. In this paper, we evaluate the experimental system consisting of the embedded OPC XML-DA server and data acquisition application, and discuss where performance bottlenecks are and how the performance can be improved of the server. Finally, we discuss the performance evaluations on the improved server and the architecture which makes effective use of the server
Solidarity. Reflections on an Emerging Concept in Bioethics. Summary
1. References to solidarity are currently on the increase in public discourse. In the UK and beyond, during economic crises and in a political climate where many feel that mutual assistance has lost currency, calls for a new and forceful emphasis on the meaning of solidarity are increasingly heard. Such appeals to solidarity are inevitably linked to ideas about how societies function, and about how and where the boundary between individual, familial, communal and societal spheres of responsibilities should be drawn.