Cycle frequency in standard Rock-Paper-Scissors games: Evidence from experimental economics

The Rock-Paper-Scissors (RPS) game is a widely used model system in game theory. Evolutionary game theory predicts the existence of persistent cycles in the evolutionary trajectories of the RPS game, but experimental evidence has remained to be rather weak. In this work we performed laboratory experiments on the RPS game and analyzed the social-state evolutionary trajectories of twelve populations of N=6 players. We found strong evidence supporting the existence of persistent cycles. The mean cycling frequency was measured to be $0.029 \pm 0.009$ period per experimental round. Our experimental observations can be quantitatively explained by a simple non-equilibrium model, namely the discrete-time logit dynamical process with a noise parameter. Our work therefore favors the evolutionary game theory over the classical game theory for describing the dynamical behavior of the RPS game.Comment: 7 Page, 3 figure; Keyword: Rock-Paper-Scissors game; cycle; social state; population dynamics; evolutionary trajector

Modeling and Hydrodynamic Characteristics of Bionic Undulate Fin Propeller Driven by Hydraulic

The bionic undulating propeller driven by hydraulic system has different structure, kinematic and dynamic characteristics than that of the common bionic undulating propellers driven by other sources. This paper highlights firstly the structure and driving mechanism of bionic undulating propeller with a hydraulic system, and then setup its kinematic model, based on ruled-surface equation. Changing rules of dynamic mesh for bionic fin is designed based on kinetic model. Later on, the changing courses of hydrodynamic force caused by the bionic undulating fin are calculated and studied with the CFD (Computational Fluid Dynamics) method, as well as the changing characteristics of the fluid pressure field. The analysis showed that while driven by hydraulic system, the bionic propeller could produce full-baseline undulating motion, and has flexible start-up process, as well as doubled-frequency character. The bionic undulating fin driven by hydraulic system puts up flexible characters on both kinematic and dynamics. Key Words: Hydraulic Driven; Undulating Fin; Bionic Propeller; Dynamic Mesh; Hydrodynamic