Robot covering problem has gained attention as having the most promising applications in our real life. Previous spanning tree coverage algorithm addressed this problem well in a static environment, but not in a dynamic one. In this paper, we present and analyze our algorithm workable in a dynamic environment with less shadow areas.

Many applications of digital image processing require the evaluation of fast Fourier transforms. Therefore, for the more conventional rectangular grid image systems, FFT algorithms have been largely developed so far. For users of hexagonal grid image systems, unfortunately, life is less easier since they generally have to write the hexagonal FFT codes by themselves. This complexity tends to hinder the development and use of the hexagonal imaging system. In this short paper, we propose, without a mathematical proof, a method to simulate hexagonal FFTs based on the relations between the two grid systems. And this is done with only the use of regular rectangular FFT schemes. By this method, a hexagonally sampled image can be easily transformed via the many FFT programs available in the market.