Do soccer players play the mixed-strategy Nash equilibrium?

Mixed-strategy Nash equilibrium (MSNE) is a commonly-used solution concept in game-theoretic models in various fields in economics, management, and other disciplines, but the experimental results whether the MSNE predicts well actual play in games is mixed. Consequently, evidence for naturally-occurring games in which the MSNE predicts the outcome well is of great importance, as it can justify the vast use of MSNE in models. The game between the kicker and goalkeeper in soccer penalty kicks is a real-world game that can be used to examine the application of the MSNE concept or its accuracy because payoffs are a common knowledge, the players have huge incentives to play correctly, the game is simple enough to analyze, its Nash equilibrium is in mixed strategies, and players' actions can be observed. We collected and analyzed data on the direction of kicks and jumps in penalty kicks in various top leagues and tournaments. Our analysis suggests that the MSNE predictions are the closest to the actual sample data, even though some other prediction methods use information on the marginal distribution of kicks or jumps whereas the MSNE does not.Soccer; Football; MSNE; Mixed-strategies; Mixed-strategy Nash equilibrium; Sports; Penalty kicks

Combined High Power and High Frequency Operation of InGaAsP/InP Lasers at 1.3μm

A simultaneous operation of a semiconductor laser at high power and high speed was demonstrated in a buried crescent laser on a P-InP substrate. In a cavity length of 300μm, a maximum CW power of 130mW at room temperature was obtained in a junction-up mounting configuration. A 3dB bandwidth in excess of 12GHz at an output power of 52mW was observed

AlGaAs lasers with micro-cleaved mirrors suitable for monolithic integration

A technique has been developed for cleaving the mirrors of AlGaAs lasers without cleaving the substrate. Micro-cleaving involves cleaving a suspended heterostructure cantilever by ultrasonic vibrations. Lasers with microcleaved mirrors have threshold currents and quantum efficiencies identical to those of similar devices with conventionally cleaved mirrors

Dynamic Windows Scheduling with Reallocation

We consider the Windows Scheduling problem. The problem is a restricted version of Unit-Fractions Bin Packing, and it is also called Inventory Replenishment in the context of Supply Chain. In brief, the problem is to schedule the use of communication channels to clients. Each client ci is characterized by an active cycle and a window wi. During the period of time that any given client ci is active, there must be at least one transmission from ci scheduled in any wi consecutive time slots, but at most one transmission can be carried out in each channel per time slot. The goal is to minimize the number of channels used. We extend previous online models, where decisions are permanent, assuming that clients may be reallocated at some cost. We assume that such cost is a constant amount paid per reallocation. That is, we aim to minimize also the number of reallocations. We present three online reallocation algorithms for Windows Scheduling. We evaluate experimentally these protocols showing that, in practice, all three achieve constant amortized reallocations with close to optimal channel usage. Our simulations also expose interesting trade-offs between reallocations and channel usage. We introduce a new objective function for WS with reallocations, that can be also applied to models where reallocations are not possible. We analyze this metric for one of the algorithms which, to the best of our knowledge, is the first online WS protocol with theoretical guarantees that applies to scenarios where clients may leave and the analysis is against current load rather than peak load. Using previous results, we also observe bounds on channel usage for one of the algorithms.Comment: 6 figure

Anomalous Microfluidic Phonons Induced by the Interplay of Hydrodynamic Screening and Incompressibility

We investigate the acoustic normal modes ("phonons") of a 1D microfluidic droplet crystal at the crossover between 2D flow and confined 1D plug flow. The unusual phonon spectra of the crystal, which arise from long-range hydrodynamic interactions, change anomalously under confinement. The boundaries induce weakening and screening of the interactions, but when approaching the 1D limit we measure a marked increase in the crystal sound velocity, a sign of interaction strengthening. This non-monotonous behavior of the phonon spectra is explained theoretically by the interplay of screening and plug flow.Comment: http://link.aps.org/doi/10.1103/PhysRevLett.99.124502 http://www.weizmann.ac.il/complex/tlusty/papers/PhysRevLett2007.pd

The absorption spectrum around nu=1: evidence for a small size Skyrmion

We measure the absorption spectrum of a two-dimensional electron system (2DES) in a GaAs quantum well in the presence of a perpendicular magnetic field. We focus on the absorption spectrum into the lowest Landau Level around nu=1. We find that the spectrum consists of bound electron-hole complexes, trion and exciton like. We show that their oscillator strength is a powerful probe of the 2DES spatial correlations. We find that near nu=1 the 2DES ground state consists of Skyrmions of small size (a few magnetic lengths).Comment: To be published in Phys Rev Lett. To be presented in ICSP2004, Flagstaff, Arizona. 4 figures (1 of them in color). 5 page