• Journal of Positioning, Navigation, and Timing
• /
• v.3 no.2
• /
• pp.83-90
• /
• 2014

In this study, to improve an existing ground-wave based time broadcasting system, a study that predicts the field distribution and field strength of the transmitted signal of a new ground-wave based time broadcasting system was performed. The prediction area was assumed to be the Korean peninsula; and to reflect the mountainous terrain of the Korean peninsula in the prediction of the variations of field distribution and field strength, a new prediction method based on the Monteath model was proposed and utilized. As field distribution changes depending on the position of a transmitter station, potential sites for the transmitter station were selected considering the geographical characteristics. In this regard, the ground conductivity information of North Korea cannot be obtained, and thus, the ground conductivity of the North Korean region was reflected considering the geological characteristics of South Korea and North Korea. Based on this, the variations of field distribution and field strength were predicted by setting the Korean peninsula as the prediction area, and the prediction results depending on the position of the transmitter station were discussed.

• BMB Reports
• /
• v.51 no.10
• /
• pp.526-531
• /
• 2018

Protein-Protein Interactions (PPIs) play essential roles in diverse biological processes and their misregulations are associated with a wide range of diseases. Especially, the growing attention to PPIs as a new class of therapeutic target is increasing the need for an efficient method of cell-based PPI analysis. Thus, we newly developed a robust PPI assay (SeePPI) based on the co-translocation of interacting proteins to the discrete subcellular compartment 'processing body' (p-body) inside living cells, enabling a facile analysis of PPI by the enriched fluorescent signal. The feasibility and strength of SeePPI (${\underline{S}}ignal$ ${\underline{e}}nhancement$ ${\underline{e}}xclusively$ on ${\underline{P}}-body$ for ${\underline{P}}rotein-protein$ ${\underline{I}}nteraction$) assay was firmly demonstrated with FKBP12/FRB interaction induced by rapamycin within seconds in real-time analysis of living cells, indicating its recapitulation of physiological PPI dynamics. In addition, we applied p53/MDM2 interaction and its dissociation by Nutlin-3 to SeePPI assay and further confirmed that SeePPI was quantitative and well reflected the endogenous PPI. Our SeePPI assay will provide another useful tool to achieve an efficient analysis of PPIs and their modulators in cells.

• BMB Reports
• /
• v.45 no.12
• /
• pp.748-753
• /
• 2012

A sequence of 10 amino acids at the C-terminus region of methylglyoxal synthase from Escherichia coli (EMGS) provides an arginine, which plays a crucial role in forming a salt bridge with a proximal aspartate residue in the neighboring subunit, consequently transferring the allosteric signal between subunits. In order to verify the role of arginine, the gene encoding MGS from a thermophile species, Thermus sp. GH5 (TMGS) lacking this arginine was cloned with an additional 30 bp sequence at the 3'-end and then expressed in form of a fusion TMGS with a 10 residual segment at the C-terminus ($TMGS^+$). The resulting recombinant enzyme showed a significant increase in cooperativity towards phosphate, reflected by a change in the Hill coefficient (nH) from 1.5 to 1.99. Experiments including site directed mutagenesis for Asp-10 in TMGS and $TMGS^+$, two dimentional structural survey, fluorescence and irreversible thermoinactivation were carried out to confirm this pathway.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.11a
• /
• pp.55-59
• /
• 2007

It is known that the adhesive interface testing of the rocket motor which using the ultrasonic wave iS superior to the other testing methods about the economically detectable abiliη of the defects. But, the signal analysis of the ultrasonic wave takes too much time and effort that the time interval of the transmitted pulse and the received pulse is too short to be separated the reflected signals because the structure of the rocket motor is multi-layers. The ultrasonic testing of rocket motor have been only applied with automatic system about extremely limited area like the debond in adhesive interface between the motor case and insulator. In this study the new technique to detect the debond between the liner and the propellant using the property of the resonance and Lamb waves was described as comparing the existence ultrasonic testing.

• Journal of Welding and Joining
• /
• v.21 no.5
• /
• pp.555-560
• /
• 2003

In automobile industry, it is necessary to reduce the weight from the view point of energy and environmental problems in these days. One of the ways for weight reduction is using adhesive aluminum structures. In this study, ultrasonic signals reflected from the adhesively bonded joint layer are used to evaluate the adhesively bonded joints. FFT is performed to determine bond-layer parameters such as effective thickness and frequency for adhesively bonded joint Al 6061 plates in comparison with the measured and theoretical ratios. And the parameters of ultrasonic wave and the J-integral are investigated to evaluate the adhesively bonded joint strength by DCB specimens.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.6
• /
• pp.654-660
• /
• 2013

This paper describes an imaging approach to detect targets behind a wall. To acquire the accurate information over the strong signals reflected by the wall and affected by multipath, a bi-static through-wall imaging radar using a noise waveform is proposed in this paper including the methodology of imaging the received signal. The complete derivation of the proposed approach is presented. And the result of tests is demonstrated to show the possibility of the proposed approach.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.32 no.1
• /
• pp.77-82
• /
• 2008

Strain-gauges have been dominantly used to measure strain at various points on a rotor, however, either a slip ring or telemetry has to be used to send sensor signals to data acquisition instruments at stationary side. Both slip ring and telemetry have numerous inherent problems which force severe limitations in real applications. This paper introduces a new rotor condition monitoring system using FBG(Fiber Bragg Grating) sensors and a rotary optical coupler. A single optical fiber with many FBG sensors is installed on the rotor and an optical dynamic interrogator is installed at stationary side. The sensor signal connection between rotating part and stationary part is made by the rotary optical coupling method which makes use of light's unique characteristic-light travels through space. Broad band light source from the interrogator travels to the optical fiber on the rotor and reflected FBG sensor signals travel back to the optical fiber on stationary side and are connected to the interrogator. Rotary optical coupler's insertion loss change due to rotation is compensated by using a reference sensor installed at the center of the rotor. The proposed system's performance has been successfully demonstrated by accurately measuring strains at 5 points on a blade rotating at high speed.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.322-326
• /
• 2008

In this paper, we have studied the images which have been reconstructed by using combination of images acquired by the variation of operating frequency. When inner images have been reconstructed, they have been superposed by the surface state effect. In this case, the images of the phase object can be enhanced by the contrast of inner images. There is a kind of specimen, one is a reference block having 1/4T, 1/2T, 3/4T side drilled holes as main run piping material of the steam generator in nuclear power plants. It has been shown that the two results of defect shapes have better than before in this processing and phase contrast grow about twice. And we have constructed the acoustic microscope by using a quadrature detector that enables to acquire the amplitude and phase of the reflected signal simultaneously. Further more we have studied the reconstruction method of the amplitude and phase images, the enhancement method of the defect images' contrast.

• Journal of Biomedical Engineering Research
• /
• v.8 no.1
• /
• pp.41-48
• /
• 1987

In estimating the freguency-dependent attenuation coefficient, we analyzed the range-dependent ultrasonic beam and proposed the method of calculating the experimental equation of beam pattern in order to reduce the error on the influence of beam pattern. These experimental equations are divided into the spectral centroid and the spec ural standard deviation slope according to axial propagation length. These are repnesented by the first-order equation in the near field of the beam and the second- order eqLlatlon In the far field. In order to prove the validity of this method, the attenuation coefficients of the non-corrected ease and the corrected case are compared. Using the reflected signal from acryle plate, the attenuation coefficients were estimated by the spectral shift method ann the spectral difference method. The result shows attenuation coeffi talents after correction are better than attenuation coefficients before correction. And this method can be applied In vivo measurement.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.1B
• /
• pp.62-70
• /
• 2000

Intelligent vehicles are equipped with radar sensors for collision avoidance. We present a method of suppressing mutual interference among pulse-type radars, where all the radars are standardized. We developed a method of separating the true self-reflection from the false one by controlling the pulse emission of a radar in anorhogonal ON, OFF pattern. Interference signal identified in OFF-intervals is recorded to indicate the positions of the expected ghosts in ON-intervals. PFA and PM are derived for a radar system with I-Q demodulation scheme, where Gaussian noise alone is Rayleigh-distributed and Gaussian noise plus reflected radar pulse are Rician-distributed. The value of the threshold adaptively updated in order to prevent the deterioration of PM. In the experimental result, PFA decreases by an order of 10,000, when compared with the conventional M of N majority voting method.