A Single Species Model with Impulsive Diffusion

In most models of population dynamics, diffusion between patches is assumedto be continuous or discrete, but in practice many species diffuse only during a single period. Inthis paper we propose a single species model with impulsive diffusion between two patches, whichprovides a more natural description of population dynamics. By using the discrete dynamical systemgenerated by a monotone, concave map for the population, we prove that the map always has a globallystable positive fixed point. This means that a single species system with impulsive diffusionalways has a globally stable positive periodic solution. This result is further substantiated bynumerical simulation. Under impulsive diffusion the single species survives in the two patches.

Synthesis of a stroboscopic image from a hand-held camera sequence for a sports analysis

This paper presents a method for synthesizing a stroboscopic image of a moving sports player from a hand-held camera sequence. This method has three steps: synthesis of background image,synthesis of stroboscopic image, and removal of player's shadow. In synthesis of background image step, all input frames masked a bounding box of the player are stitched together to generate a background image. The player is extracted by an HOG-based people detector.In synthesis of stroboscopic image step, the background image, the input frame, and a mask of the player synthesize a stroboscopic image. In removal of shadow step, we remove the player's shadow which negatively affects an analysis by using mean-shift. In our previous work, synthesis of background image has been timeconsuming. In this paper, by using the bounding box of the player detected by HOG and by subtracting the images for synthesizing a mask, computational speed and accuracy can be improved. These have contributed greatly to the improvement from the previous method.These are main improvements and novelty points from our previous method. In experiments, we confirmed the effectiveness of the proposed method, measured the player's speed and stride length, and made a footprint image. The image sequence was captured under a simple condition that no other people were in the background and the person controlling the video camera was standing still, such like a motion parallax was not occurred. In addition, we applied the synthesis method to various scenes to confirm its versatility.

Simulations to study the static polarization limit for RHIC lattice

A study of spin dynamics based on simulations with the Polymorphic Tracking Code （PTC） is reported, exploring the dependence of the static polarization limit on various beam parameters and lattice settings for a practical RHIC lattice. It is shown that the behavior of the static polarization limit is dominantly affected by the vertical motion, while the effect of beam-beam interaction is small. In addition, the ＂nonresonant beam polarization＂ observed and studied in the lattice-independent model is also observed in this lattice-dependent model. Therefore, this simulation study gives insights of polarization evolution at fixed beam energies, that are not available in simple spin tracking.