Formal veri cation for complex concurrent systems is a computationally intensive and, in some cases, intractable process. The complexity is an inherent part of the veri cation process due to the system complexity that is an exponential function of the sizes of its components. However, some properties can be enforced by automatically synchronizing the components, thus eliminating the need for ve...

This white paper lays out some foundational information about different approaches to safety: how various industries differ in their approaches to safety engineering, and a comparison of three general approaches to safety (system safety, industrial safety engineering, and reliability engineering). An attempt is made to lay out the properties of industries and systems that make one approach more...

Molecular-electronic transducers (MET) have a high conversion coefficient and low power consumption, and do not require precision mechanical components thus allowing the construction of cost- and power-efficient seismic accelerometers. Whereas the instrumental resolution of a MET accelerometer within the 0.1-100 Hz frequency range surpasses that of the best Micro-Electro Mechanical Systems (MEM...

Safety case development is not a post-development activity, rather it should occur throughout the system development lifecycle. The key components in a safety case are safety arguments. Too often, safety arguments are constructed without proper reasoning. Inappropriate reasoning in safety arguments could undermine a system’s safety claims, which in turn contributes to safety-related failures of...

Abstract To reduce computation time, the inherent strain (IS) method is popular. It consists in adding layers, at room temperature, with an “inherent strain” representing plastic deformation undergone during deposition. An IS developed, including a direct determination of tensor based on transient thermo-elastic-viscoplastic (TEVP) simulation. Validation achieved: taking full-field strains, all...

For any software system upon which lives depend, the most important question one can ask about it is, ‘How do we know the system is safe?’ Despite the critical importance of this question, no widely accepted, generally applicable answer exists. Instead, debate continues to rage over the question, with theorists and practitioners quarrelling with each other and amongst themselves. This paper sug...

Modern automation systems incorporate (Safety Integrity Level) SIL certified Safety Instrumented Systems (SIS) as an inherent part of the system. Phrases such as “integrated but separate” are often used to illustrate the undiminished safety integrity of these fully integrated automation systems. This paper will cover how an Integrated Safety System (one that performs both basic process control ...

In the first part of the paper, I propose a framework for focus and question interpretation. While both serve to introcude alternatives, I offer reasons that the two kinds of alternatives arise on different levels of semantic interpretation. The resulting approach can correctly account for all possible constellations of focus and questions, including intervention effects, without the use of typ...

T he UK Parliament recently debated and then approved legislation to allow mitochondrial replacement (MR) to be used in the clinic. However, we are concerned that some of the science of MR has been misunderstood or otherwise given only fleeting consideration. We set out our arguments below and offer a way forward to ensure that MR can safely deliver the health benefits it promises for those suf...

1 Who knoWs a utility representation Repeatedly it is alleged that this or that theory concerns a decision maker maximizing some utility function. But, as I have been at pains to discuss, the representation is not a creature of the decision maker but of the scientist studying the decision maker’s behavior “The representation theorems go in only one direction: from behavioral and structural prop...