Jaewon Choi

Real-time surface plasmon resonance dispersion imaging with a wide range of incident angles and detection wavelengths

We present a wide range of angle- and wavelength-resolved, real-time surface plasmon resonance (SPR) dispersion imaging techniques. Two-dimensional SPR dispersion images were obtained in real time by utilizing a hemicylindrical shaped prism having a high refractive index of 1.72 and a short focal length lens. Our system covers a wide range of incident angles (up to 30) and can detect wavelengths over the whole visible region, allowing us to simultaneously detect the SPR dispersion images produced by air and water substrates (refractive indices of 1 and 1.33, respectively) without scanning or moving the SPR system.

Isolated Mini-domain for Trusted Cloud Computing

On the cloud system, guest domains for cloud customers can be attacked by one of administrators with privilege or remote hackers who can compromise management tools. Therefore, the customers need a guarantee that their domains run on the secure environment with a protection against them. In this paper, we examine the security issues incurred by I/O model of hyper visors with a management domain, and propose an isolated mini-domain to protect the guest domains under the untrustworthy environment by addressing those issues.

Efficiency optimized asymmetric half-bridge converter with hold-up time compensation

In this paper, a new asymmetric half-bridge (AHB) converter integrated with hold-up time compensation circuit is proposed. The AHB converter is one of the most promising topologies in low-to-mid power applications because of zero-voltage switching (ZVS) of all switches and small number of components. But when the converter is designed considering the hold-up time condition, it has large transformer offset-current and small transformer turns-ratio. Although many researchers have studied to solve this problem, the advantages of conventional works are limited by losses from additional components. To solve this problem, a new AHB converter with an optimized efficiency is proposed in this paper. Since the proposed converter increases voltage gain using integrated boost converter during the hold-up time, it can be designed to obtain an optimized efficiency in nominal state, without losses from the additional components.

Simultaneous investigation of shear modulus and torsional resonance of solid He 4

We investigate the origin of a resonant period drop of a torsional oscillator (TO) containing solid

Three-switch LLC resonant converter for high efficiency adapter with universal input voltage

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Asymmetrical half-bridge converter with reduced DC-offset current in transformer

He by inspecting its relation to a change in elastic modulus. To understand this relationship directly, we measure both phenomena simultaneously using a TO with a pair of concentric piezoelectric transducers inserted in its annulus. Although the temperature,

Half bridge LLC resonant converter with high voltage gain for single-phase AC/DC power system

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Information of group-correlations in Korean financial market

He concentration, and frequency dependence are essentially the same, a marked discrepancy in the drive amplitude dependence is observed. We find that this discrepancy originates from the anisotropic response of polycrystalline solid

Identifying the structure of group correlation in the Korean financial market

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Numerical simulation of the zebra pattern formation on a three-dimensional model

He connected with low-angle grain boundaries by studying the shear modulus parallel to and perpendicular to the driving direction.