Kiyong Kim

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—Some of the modern voltage regulator systems are utilizing the proportional, integral, and derivative (PID) control for stabilization. Two PID tuning approaches, pole placement and pole–zero cancellation, are commonly utilized for commissioning a digital excitation system. Each approach is discussed including its performance with three excitation parameter(More)
While technological advances in existing types of optical sources are likely to define the near future, new and as yet unrealized mechanisms of light generation may play a significant role further into the future. This may be particularly true in the terahertz frequency regime where sources and detectors are an active field of development 1. Loosely defined(More)
We construct field shapes with distinct amplitude profiles that have nearly identical second-harmonic generation frequency-resolved optical gating (SHG FROG) traces. Although such fields are not true mathematical ambiguities, they result in experimentally indistinguishable FROG traces. These fields are neither time-reversed copies nor pulselets with a mere(More)
By irradiating an ultra-thin overdense foil with an intense circularly polarized laser beam, the laser radiation pressure can push the foil forward. This scheme, laser radiation pressure acceleration, is one of the most actively studied laser-plasma acceleration scheme to generate quasi-monoenergetic proton beams. However, during the acceleration process,(More)
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