Model-Driven safety evaluation with state-event-based component failure annotations

Over the past years, the paradigm of component-based software engineering has been established in the construction of complex mission-critical systems. Due to this trend, there is a practical need for techniques that evaluate critical properties (such as safety, reliability, availability or performance) of these systems. In this paper, we review several high-level techniques for the evaluation of safety properties for component-based systems and we propose a new evaluation model (State Event Fault Trees) that extends safety analysis towards a lower abstraction level. This model possesses a state-event semantics and strong encapsulation, which is especially useful for the evaluation of component-based software systems. Finally, we compare the techniques and give suggestions for their combined usage

Numerical evaluation of e-fields induced by body motion near high-field MRI scanner

In modern magnetic resonance imaging (MRI), both patients and radiologists are exposed to strong, nonuniform static magnetic fields inside or outside of the scanner, in which the body movement may be able to induce electric currents in tissues which could be possibly harmful. This paper presents theoretical investigations into the spatial distribution of induced E-fields in the human model when moving at various positions around the magnet. The numerical calculations are based on an efficient, quasistatic, finite-difference scheme and an anatomically realistic, full-body, male model. 3D field profiles from an actively-shielded 4 T magnet system are used and the body model projected through the field profile with normalized velocity. The simulation shows that it is possible to induce E-fields/currents near the level of physiological significance under some circumstances and provides insight into the spatial characteristics of the induced fields. The results are easy to extrapolate to very high field strengths for the safety evaluation at a variety of field strengths and motion velocities.

Safety issues in functional capacity evaluation: Findings from a trial of a new approach for evaluating clients with chronic back pain

Although safety is recognized as a critical issue in functional capacity evaluations (FCEs), it has rarely been investigated. This paper reports on the findings of a study which examined safety aspects of a new approach to FCE. Fourteen rehabilitation clients with chronic back pain participated in the study. Aspects examined included the pre-FCE screening procedures, the monitoring of performance and safety during the FCE, and the end of FCE measures and follow-up procedures. Support was found for the screening procedures of the approach, particularly blood pressure measurement, and for the combined approach to monitoring of the persons performance from biomechanical, physiological and psychophysical perspectives. Issues for FCE safety in general are identified and discussed, including the importance of screening procedures to determine readiness for FCEs and the issue of load handling in FCEs, especially in relation to clients with chronic back pain.