Turing machines can be efficiently simulated by the General Purpose Analog Computer

The Church-Turing thesis states that any sufficiently powerful computational model which captures the notion of algorithm is computationally equivalent to the Turing machine. This equivalence usually holds both at a computability level and at a computational complexity level modulo polynomial reductions. However, the situation is less clear in what concerns models of computation using real numbers, and no analog of the Church-Turing thesis exists for this case. Recently it was shown that some models of computation with real numbers were equivalent from a computability perspective. In particular it was shown that Shannon's General Purpose Analog Computer (GPAC) is equivalent to Computable Analysis. However, little is known about what happens at a computational complexity level. In this paper we shed some light on the connections between this two models, from a computational complexity level, by showing that, modulo polynomial reductions, computations of Turing machines can be simulated by GPACs, without the need of using more (space) resources than those used in the original Turing computation, as long as we are talking about bounded computations. In other words, computations done by the GPAC are as space-efficient as computations done in the context of Computable Analysis

Social Construction Of Safety In Uas Technology In Concrete Settings: Some Military Cases Studied

Unmanned aerial systems (UASs) in general and UAS safety in particular have so far received little attention in the science, technology and society (STS) literature. This paper therefore reports on several (military) cases of this relatively new technology, focusing specifically on issues of safety. Quite often, safety of technology is considered the result of a rational process – one of a series of rational, often calculative, linear steps. The paper’s results suggest that establishing safety in military UASs is very much a social process. Approaching (military) UAS safety from this perspective could perhaps be complementary to more analytical and rational perspectives on safety of this type of technology. Further research is therefore suggested on the implications that social processes can have for safety in UASs. So far, it seems, such a position on safety in technology has been little explored in both the STS and safety literature explicitly

Organizing safety in security organizations

Safety and security are often regarded as two separate concepts, both scientifically and organizationally. Both are often seen as two fundamentally conflicting institutional demands and their agendas as being based on two profoundly different organizing principles. Because of this, safety may get less attention in security organizations than necessary as such a distinction would mean in the perception of people that funding for the one would go at the cost of the other. This chapter points out that organizing for security and for safety may not be so different after all as both safety and security seem to develop from the same social structures and institutional complexities. The differences between the two seem to be a matter of social construction, power and policy, rather than that these differences would inevitably follow from what one would regard as their intrinsic features

Auftragstaktik: Een basis voor modern veiligheidsmanagement?

Binnen het militaire domein houdt men ten aanzien van het bewerkstelligen van veiliger werken veelal vast aan klassieke benaderingswijzen. Deze richten zich voornamelijk op het verhogen van de individuele kwaliteit en de betrouwbaarheid van afzonderlijke onderdelen. Veiligheidsanalyses in dit soort visies voeren langs voorgedefinieerde processtappen. Dit artikel legt een koppeling tussen deze klassieke benaderingswijzen van veiligheid en de principes van Normaltaktik, en tussen modernere visies op veiligheid en de principes van Auftragstaktik. Het huidige strijdtoneel noodzaakt vanwege de complexiteit meer en meer tot het aansturen op hogere-orde doelen, oftewel Auftragstaktik. Het heeft er alle schijn van dat het streven naar veiliger werken in dergelijke complexe omgevingen en ook de analyse daarvan zich slecht laten verenigen met het volgen van rigide stappenplannen. Als dit inderdaad het geval is, dan is het hanteren van louter klassieke veiligheidsmanagementsprincipes niet meer dan window dressing

Interacting with Classic Design Engineering

Triggered by our occasionally tense field experiences relating to the implementation and institutionalization of usability in design engineering organizations that are characterized by traditional engineering education and thinking, we have earlier suspected that the activities associated with human-centered design were orthogonal to the design engineering practices otherwise in place. While noting that other human factors professionals have had comparable challenges relating to multidisciplinary design, we have, however, reached a point where we rather are suggesting that the ontological, epistemological and methodological grounding of classic design engineering, under some circumstances, could be the direct cause for friction between that discipline and that of human factors. In a way taking our own medicine, we have thus arrived at a place where we are realizing the need for an ethnographical exploration and improved understanding of classic design engineering fundamentals, appreciating that a more successful and fruitful interaction and cooperation with that essential discipline very well could spring from a deeper and more nuanced understanding of the mindset of the classic design engineer. The main part of the present paper pivots around developing such an insight, hoping to contribute to the effective, efficient and satisfactory outcome of multidisciplinary cooperation for those who find themselves being tasked with human-centric work in traditional engineering organizations

From Normaltaktik to Auftragstaktik: Lessons for Safety in the Military

In their initiatives to achieve organizational safety goals, managers, but also members of safety institutes – such as regulators – often seem to follow what in the military might be called “normaltaktik” or “order-type tactics”. Also military attitudes towards safety seem to resemble and reinforce normaltaktik. This is somewhat ironic since the military has been forced more and more in the past decennium towards non-conventional warfare – and thus away from the application of normaltaktik. If we would approach safety not from a normaltaktiker but from an auftragstaktiker perspective, not only could this reduce accidents, it could give us a strategic advantage