6,190 research outputs found
Periodic Strategies: A New Solution Concept and an Algorithm for NonTrivial Strategic Form Games
We introduce a new solution concept, called periodicity, for selecting
optimal strategies in strategic form games. This periodicity solution concept
yields new insight into non-trivial games. In mixed strategy strategic form
games, periodic solutions yield values for the utility function of each player
that are equal to the Nash equilibrium ones. In contrast to the Nash
strategies, here the payoffs of each player are robust against what the
opponent plays. Sometimes, periodicity strategies yield higher utilities, and
sometimes the Nash strategies do, but often the utilities of these two
strategies coincide. We formally define and study periodic strategies in two
player perfect information strategic form games with pure strategies and we
prove that every non-trivial finite game has at least one periodic strategy,
with non-trivial meaning non-degenerate payoffs. In some classes of games where
mixed strategies are used, we identify quantitative features. Particularly
interesting are the implications for collective action games, since there the
collective action strategy can be incorporated in a purely non-cooperative
context. Moreover, we address the periodicity issue when the players have a
continuum set of strategies available.Comment: Revised version, similar to the one published in Advances in Complex
System
Blending of Polyhydroxybutyrate-co-valerate with Polylactic Acid for Packaging Applications – Reflections on Miscibility and Effects on the Mechanical and Barrier Properties
Biopolymers for packaging applications offer many advantages and are therefore of increasing interest. In order to develop a sustainable alternative for petrochemical-based polymers the biobased and biodegradable polymers, the focus of this work are polyhydroxybutyrate-co-valerate (PHBV) and polylactic acid (PLA) (and copolymers). Blending of these two biopolymers was reviewed under thermodynamic aspects and backed with own results. Additionally, different ways of improving the miscibility were performed by compatibilisers, peroxides, transesterification catalysts, and by blending PHBV with modified molecular weight. These blends were extruded as cast films, and characterised by means of mechanical and barrier properties. This study analyses the miscibility of PLA and PHB-copolyester (with approximately equal molar masses) and reports on the unusually high barrier properties in PLA and PHBV blends. However, the quality of blending, especially regarding barrier properties to interphase boundaries, depends on the compatibility of the components and the morphology of the blend. Our results suggest that a PHBV content of 20–35 % in PLA is the most suitable blend system in terms of compatibility and high barrier properties
INVERSE DYNAMICS OF TAKE-OFF ON SKI-JUMPING SIMULATOR
A special take-off simulator for ski-jumping was constructed to enable training of jumping skills. An inverse dynamics model was used to evaluate a take-off technique on that simulator. A 3D video based kinematical system was used to obtain body coordinates, which were then transformed to 2D sagittal plane. From a five link segment model the joint forces in horizontal and vertical direction as well as joint torques were calculated. Results showed sufficient sensitiveness of the method for a take-off assessment. A vibration effect, probably due to the low approaching velocity and thus a poorer balance, was observable, what was not a case in a normal snow conditions
Mode spectrum and temporal soliton formation in optical microresonators
The formation of temporal dissipative solitons in optical microresonators
enables compact, high repetition rate sources of ultra-short pulses as well as
low noise, broadband optical frequency combs with smooth spectral envelopes.
Here we study the influence of the resonator mode spectrum on temporal soliton
formation. Using frequency comb assisted diode laser spectroscopy, the measured
mode structure of crystalline MgF2 resonators are correlated with temporal
soliton formation. While an overal general anomalous dispersion is required, it
is found that higher order dispersion can be tolerated as long as it does not
dominate the resonator's mode structure. Mode coupling induced avoided
crossings in the resonator mode spectrum are found to prevent soliton
formation, when affecting resonator modes close to the pump laser. The
experimental observations are in excellent agreement with numerical simulations
based on the nonlinear coupled mode equations, which reveal the rich interplay
of mode crossings and soliton formation
Representation of Markov chains by random maps: existence and regularity conditions
We systematically investigate the problem of representing Markov chains by
families of random maps, and which regularity of these maps can be achieved
depending on the properties of the probability measures. Our key idea is to use
techniques from optimal transport to select optimal such maps. Optimal
transport theory also tells us how convexity properties of the supports of the
measures translate into regularity properties of the maps via Legendre
transforms. Thus, from this scheme, we cannot only deduce the representation by
measurable random maps, but we can also obtain conditions for the
representation by continuous random maps. Finally, we present conditions for
the representation of Markov chain by random diffeomorphisms.Comment: 22 pages, several changes from the previous version including
extended discussion of many detail
Transport and thermoelectric properties of the LaAlO/SrTiO interface
The transport and thermoelectric properties of the interface between
SrTiO and a 26-monolayer thick LaAlO-layer grown at high
oxygen-pressure have been investigated at temperatures from 4.2 K to 100 K and
in magnetic fields up to 18 T. For 4.2 K, two different electron-like
charge carriers originating from two electron channels which contribute to
transport are observed. We probe the contributions of a degenerate and a
non-degenerate band to the thermoelectric power and develop a consistent model
to describe the temperature dependence of the thermoelectric tensor. Anomalies
in the data point to an additional magnetic field dependent scattering.Comment: 7 pages, 4 figure
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