Dong-Hyun Kim

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Quantitative assessment of the myelin water content in the brain can substantially improve our understanding of white matter diseases such as multiple sclerosis. In this study, in vivo myelin water content was estimated using T(2)* relaxation with multi-slice acquisitions in magnetic resonance imaging (MRI). The main advantages of using T(2)* relaxation are(More)
A fat-saturated twice-refocused spin echo sequence was implemented on a GE Signa 1.5-T whole-body system for diffusion-weighted imaging. Data were acquired using an analytically designed interleaved variable-density (VD) spiral readout trajectory. This flexible design algorithm allowed real-time prescription on the scanner. Each interleaf of the VD spiral(More)
In cloud computing, the lightweight, efficient and secure authentication scheme is needed because it is to handle large amounts of data in real-time. Hence, this paper proposes an efficient and lightweight multi-user authentication scheme based on cellular automata (CA) in cloud computing environments. In the proposed scheme, an authentication process is(More)
The double inversion recovery (DIR) imaging technique has various applications such as black blood magnetic resonance imaging and gray/white matter imaging. Recent clinical studies show the promise of DIR for high resolution three dimensional (3D) gray matter imaging. One drawback in this case however is the long data acquisition time needed to obtain the(More)
The increase in pattern complexity due to optical proximity correction (OPC), the tight requirements for critical dimension (CD) control and the difficulties in defect inspections make IC manufacture more expensive. To alleviate the high cost, manufacturing requirements must be handled at the design stage to improve the quality and yield of ICs. We(More)
Variable density spirals have been proposed in a variety of applications, including MR fluoroscopy, cardiac imaging, and MR spectroscopic imaging. In this work, a simple analytic solution for designing a flexible set of variable density spiral trajectory waveforms is presented. The method enables real-time waveform prescription on scanners with limited(More)
A regularized algorithm is presented for localized in vivo shimming. The technique uses first- (X,Y,Z), second- (Z(2), ZX, ZY, X(2)-Y(2), XY), and third-order (Z(3)) shim coils, and is robust when applied to arbitrarily-shaped, as well as off-center, regions of interest (ROIs). A single-shot spiral pulse sequence is used for rapid field map acquisition, and(More)
MR Electric Properties Tomography (EPT) is a lately developed medical imaging modality capable of visualizing both conductivity and permittivity of the patient at the Larmor frequency using B 1 maps. The paper discusses the development of EPT reconstructions, EPT sequences, EPT experiments, and challenging issues of EPT.
A scheme is proposed for producing ps length pulses of x-ray radiation from the Advanced Light Source (ALS) using two RF deflecting cavities. The cavities create vertical displacements of electrons correlated with their longitudinal position in the bunch. The two cavities separated by 180 degrees of vertical phase advance. This allows the vertical kick from(More)
Along with the commercialization of the Internet of Things (IoT) technology, the demand for long-range, low-power and long-range, large amount of data transmission arises. However, there has been no such communication technology to satisfy the transmission. The Wi-Fi is able to send large amounts of data with its broadband technology, but because of high(More)