The tropical shadow-vertex algorithm solves mean payoff games in polynomial time on average

We introduce an algorithm which solves mean payoff games in polynomial time on average, assuming the distribution of the games satisfies a flip invariance property on the set of actions associated with every state. The algorithm is a tropical analogue of the shadow-vertex simplex algorithm, which solves mean payoff games via linear feasibility problems over the tropical semiring $(\mathbb{R} \cup \{-\infty\}, \max, +)$. The key ingredient in our approach is that the shadow-vertex pivoting rule can be transferred to tropical polyhedra, and that its computation reduces to optimal assignment problems through Pl\"ucker relations.Comment: 17 pages, 7 figures, appears in 41st International Colloquium, ICALP 2014, Copenhagen, Denmark, July 8-11, 2014, Proceedings, Part

Algebraic Properties of Effectivity Functions.

voting ; social planning ; game theory ; economic equilibrium

Tight Cyclic Game Forms.

information ; game theory ; economic equilibrium

The region of two-point coherence enhancement after backscattering through turbulence

Experimental observations of the backscattered intensity distribution after double passage through turbulence using a polarisation interferometer are described and discussed. The existence of regions in which there is an enhancement of coherence is demonstrated and explained

Huddersfield Open Access Publishing (HOAP) Project

The JISC funded Huddersfield Open Access Publishing (HOAP) Project aimed to develop a low cost sustainable Open Access (OA) journal publishing platform using EPrints Institutional Repository software. This poster will report on the development of the HOAP platform and discuss the outcomes of the project. The platform was developed to convert the peer reviewed, Teaching in Lifelong Learning journal, from its existing print subscription model to an OA e-journal. A specific front end was created for the journal, with content being archived in the University Repository. As part of this work, there has been a re-write of the notes for contributors section and a move from copyright transfer to a licence to publish model. HOAP is now a member of CrossRef and the Committee on Publishing Ethics, the journal has also been submitted to the Directory of Open Access Journals. The platform will also be used to launch a new title, Huddersfield Research Review during 2012. This title will showcase the most significant research at the University of Huddersfield by including interviews with the authors of the most cited and/or downloaded articles in the Repository together with an editorial overview by a senior researcher who will locate Huddersfield research within the broader national and international literature in the relevant fields and disciplines. An audit of the University’s journals resulted in the addition of another title during the project and also the potential for five others to be hosted, including two new peer-reviewed OA titles in 2012. In order to disseminate its output, the project developed a toolkit for other institutions, including new workflows, a licence to publish template and guidelines for new title proposals. The project hopes the toolkit will inspire other institutions to investigate OA journal publishing. A major output of HOAP for Huddersfield has been a fundamental change in the understanding of the utility of Institutional Repositories in which ‘innovation’ and ‘impact’ displace ‘management’ and ‘preservation” as the primary functions. The HOAP platform provides not only an interface through which both original and archived peer-reviewed content can be delivered in a sustainable OA format but also a means of delivering specialist content to specific academic audiences through a traditional journal front-end. The poster will share the recommendations for further developments at Huddersfield and implications for the wider community

Observation of the enhancement of coherence by backscattering through turbulence

We present results of an experiment in which a plane mirror is coherently illuminated and viewed through a turbulent cell. Using a two-pinhole aperture in the pupil plane for both illumination and viewing, we have obtained time-averaged images containing fringes. This gives qualitative confirmation of theoretical predictions claiming that the enhanced back-scattering effect may be used to image deterministic objects. © 1992