Appropriate small scale mechanization

Poster prepared for a share fair, Addis Ababa, May 201

Infinite majesty : disabled and athletic métis in David Foster Wallace’s tennis writing

As John Jeremiah Sullivan remarks in his introduction to String Theory, a collection of David Foster Wallace’s essays on tennis, tennis “may be [Wallace’s] most consistent theme at the surface level.” As once an elite junior professional himself, Wallace reflects on and writes from his own involvement in the sport, with the conditioning, strategy, and body-mind training that goes into it. In other essays of String Theory, Wallace reaches beyond his personal playing experience, observes professional tennis players with their incredible grace, and creates his own tennis playing students in Infinite Jest. Throughout these fictional and nonfictional accounts, he conceptualizes what such eminent athleticism entails. This paper will show that celebrated athleticism in Wallace’s work exhibits an embodimental métis, or an acute, crafty body-mind knowledge of its movement through space. Beyond only characterizing athletic movement, however, this paper argues that the same concept of métis extends to people with disabilities, including characters with disabilities in Infinite Jest. The same hyperawareness of corporeality, versatile methods of adjusting to oppositional contexts, and extraordinary complexity are shared by both groups. Using rhetorical scholarship on métis and disability theories of embodiment and social representation, this paper will draw parallels between the moving body-minds of athletic and disabled bodies and trace the implications of this analogy for Wallace’s work and disability studies.Englis

Magnetic and electric phase control in epitaxial EuTiO3_3 from first principles

We propose a design strategy - based on the coupling of spins, optical phonons, and strain - for systems in which magnetic (electric) phase control can be achieved by an applied electric (magnetic) field. Using first-principles density-functional theory calculations, we present a realization of this strategy for the magnetic perovskite EuTiO$_3$.Comment: Significantly revised for clarit

Optimal Time-Abstract Schedulers for CTMDPs and Markov Games

We study time-bounded reachability in continuous-time Markov decision processes for time-abstract scheduler classes. Such reachability problems play a paramount role in dependability analysis and the modelling of manufacturing and queueing systems. Consequently, their analysis has been studied intensively, and techniques for the approximation of optimal control are well understood. From a mathematical point of view, however, the question of approximation is secondary compared to the fundamental question whether or not optimal control exists. We demonstrate the existence of optimal schedulers for the time-abstract scheduler classes for all CTMDPs. Our proof is constructive: We show how to compute optimal time-abstract strategies with finite memory. It turns out that these optimal schedulers have an amazingly simple structure - they converge to an easy-to-compute memoryless scheduling policy after a finite number of steps. Finally, we show that our argument can easily be lifted to Markov games: We show that both players have a likewise simple optimal strategy in these more general structures