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Summary There has been a huge increase in interest in blockchain technology. However, little is known about the drivers behind the adoption of this technology. In this article we identify and analyze these drivers, using six real‐world and representative scenarios. We confirm in our analysis that blockchain is not an appropriate technology for some scenarios, from a purely technical point of view. The choice for blockchain technology in such scenarios may therefore seem as an irrational choice. However, our analysis reveals that there are nontechnical drivers at play that drive the adoption of blockchain, such as philosophical beliefs, network effects, and economic incentives. These nontechnical drivers may explain the rationality behind the choice for blockchain adoption.

Self driving cars have recently attracted academia and industry interest. As planning algorithms become responsible for critical decisions, many questions concerning traffic safety arise. An increased automation level demands proportional impact on safety requirements, currently governed by the ISO 26262 standard. However, ISO 26262 sees safety as a functional property of a system and fails to cover emergent concerns related to autonomous decisions. In order to fill this gap we propose the field of tactical safety, which extends safety analysis to planning and execution of driving maneuvers, response to traffic events or autonomous system failures. It is meant to complement, not to replace functional safety properties of a system and allows the analysis of autonomous agents from a safe behavior point of view. We draw the requirements for tactical safety from an automotive standard which defines functional elements for advanced driving automation systems.

We apply model learning on three SSH implementations to infer state machine models, and then use model checking to verify that these models satisfy basic security properties and conform to the RFCs. Our analysis showed that all tested SSH server models satisfy the stated security properties, but uncovered several violations of the standard.

Expansion postponement is a tantalisingly simple conjecture about pure type systems which has so far resisted all attempts to prove it for any interesting class of systems. We prove the property for all normalising pure type systems, and discuss the connection with typechecking.