Toshio Koike

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A high-performance speed control system for cage induction motors is described which utilizes a PWM inverter. The effects of primary current coincidence and machine constant variation on system characteristics such as response time, torque precision, and operating noise were investigated. Based on the results obtained, new control methods have been devised;(More)
The NASA Cold-land Processes Field Experiment-1 (CLPX-1) involved several instruments in order to acquire data a t different spatial resolutions. Indeed, one of the main tasks of CLPX-1 was to explore scaling issues associated with microwave remote sensing of snowpacks. To achieve this task, microwave brightness temperatures collected at 18.7, 36.5, and 89(More)
In this paper, we propose a powered visualizer for earth environmental science (PVES) which can accommodate three-dimensional (3-D) datasets. Though a data integration system called the Information Fusion Reactor for Earth Environmental Science (IFRES) is being developed at the Institute of Industrial Science at the University of Tokyo, PVES is a part of(More)
We develop a new data assimilation algorithm by employing a heuristic optimization approach named very fast simulated re-annealing (VFSA), which is capable of minimizing the cost function without using the adjoint model. The method is independent on model operator and observation operator, and has advantages in dealing with strong nonlinearities and(More)
Soil moisture is the central focus of land surface and atmospheric modeling because it controls surface water and energy fluxes and consequently affects land–atmosphere interactions. Although global or regional satellite-derived surface soil moisture data sets are readily available, knowledge about assimilating them into numerical weather prediction (NWP)(More)
[1] Soil moisture is a very important variable in land surface processes. Both field moisture measurements and estimates from modeling have their limitations when being used to estimate soil moisture on a large spatial scale. Remote sensing is becoming a practical method to estimate soil moisture globally; however, the quality of current soil surface(More)