Robust Self-Triggered Control for Nonlinear Cyber-Physical Systems with State Constraints under DoS Attacks

This paper is concerned with the event-based control problem for nonlinear cyber-physical systems (CPSs) with state constraints. A novel security control strategy consisting of a self-triggered mechanism is developed to decrease the network communication loads to the most extent on the basis of ensuring system safety and stability. The maximum capability of the designed self-triggered mechanism to resist denial-of-service (DoS) attacks occurring in controller-actuator (C-A) and sensor-controller (S-C) channels synchronously is also analyzed. In particular, we prove that the security control strategy guarantees the system safety and stability without resulting in Zeno behavior. Finally, a numerical example is provided to demonstrate the prominent effectiveness and the advantages over the existing results.

Survey Use to Validate Engineering Methodology and Enhance System Safety

Surveys and the resulting data provide powerful insights to an item or concept being assessed. Not only do they garner feedback that can be used to enhance the item, but, in the instance of this article, they can enhance the validity of positive change via novel concepts prior to spending the time and money in incorporating these concepts and running the risk of negligible meaningful return. In an effort to ensure the validity of proposed novel methods in a design engineering context, a survey was developed and administered to engineering subject matter experts. This was done to not only ensure that the proposed methods would be viable if implemented but gave confidence in the results of the research that drove the method development. This assessment activity served as a risk reduction activity to ensure smooth implementation of the methods from both an efficiency standpoint and, most importantly, as part of maximizing system safety. This paper discusses the composition and considerations of the survey administered in the research study, in addition to the survey results with the intention of providing a format for others in a similar context to glean from and, if practical, replicate the method.

Model-based safety assessment for conceptual aircraft systems design

Traditional system technology modeling in conceptual aircraft design mainly relies on empirical knowledge and methods derived from conventional systems, for which valid system architecture designs are known. Since these systems have been proven valid especially from a safety perspective, detailed system safety analyses are usually not necessary. For unconventional systems and innovative technologies, on contrary, new architectures have to be designed and system safety has, therefore, to be taken into account. Therefore, the application of model-based safety assessment (MBSA) for designing system architectures in conceptual aircraft design studies is proposed. A MBSA approach based on a Simulink architecture model is presented which is tailored for use in conceptual design studies. It is applied to the cryocooling system of a hybrid-electric powertrain architecture from an already-published study. The original architecture as well as possible architecture alternatives are investigated. As a result, a safer architecture version with lower number of components can be proposed. The application example indicates that using MBSA in conceptual design benefits the latter by providing insights into safety properties of the system and by pointing out architecture safety weaknesses. This could result in safer, thus more realistic system architectures.