Yoshiharu Omura

Learn More
This paper proposes a new method for Particle-in-Cell (PIC) simulations which aims at achieving both good load balancing and scalability so as to be efficiently executed on distributed memory systems. This method, named <i>OhHelp</i>, simply and equally partitions the space domain where charged particles reside and assigns each partitioned subdomain to each(More)
A decomposition scheme was applied to ALOS/PALSAR data obtained from a fast-growing tree plantation in Sumatra, Indonesia to extract tree stem information and then estimate the forest stand volume. The scattering power decomposition of the polarimetric SAR data was performed both with and without a rotation matrix and compared to the following(More)
We propose a distributed upconverter with composite right/left handed (CRLH) transmission lines (TLs) and its design method. An upconverter MMIC is fabricated by using this design method. The upconverter shows frequency dividing operation by setting RF, LO, and IF frequencies, and achieves image rejection features without image rejection filters or blocks.(More)
We study the cyclotron maser instability (CMI) driven by an energetic ring-beam distribution by a particle simulation to explain possible generation mechanisms of intense radiation phenomena observed in space. The main objective is to understand the nonlinear processes that control saturation of the emission process. Our study reveals new issues that have(More)
In order to evaluate the spacecraft-plasma interactions quantitatively, we have been developing "Geospace Environment Simulator (GES)". A proto model of GES called NuSPACE is an electromagnetic Particle-In-Cell (PIC) simulation code and has been optimized to achieve the high performance with the Earth simulator. To test NuSPACE, we examined the space(More)
  • 1