• Progress in Medical Physics
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• v.13 no.2
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• pp.85-89
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• 2002

We authors developed a new small-size birdcage RF coil for animal MR images. And we compared signal-to-noise ratio (SNR) of the new small coil with a conventional knee coil. The dimension of the low-pass type birdcage coil with 12 elements at 37 MRI system are 13 cm outer diameter, 12 cm inner diameter and 20 cm length. For each element, the width of copper tape is 0.05 mm, thickness is 8 mm and length is 20 cm. The small birdcage coil with 12 elements exhibited 7 resonance modes. The isolation of the quadrature channel could be achieved more than 20 ㏈. The coil quality factor (Q value) was 98.6. The SNR of the animal coil was 243.2 on the average and was about twice as high as the conventional knee coil. The present study successfully demonstrated that the small birdcage coil could provide high quality animal MR images with the improved SNR. Therefore, it is expected that the small birdcage coil could be used in the clinical diagnosis and research studies for veterinary medicine in the near future.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.2
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• pp.76-82
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• 2011

In this paper, we propose the technique to detect the location and size of the small target in multi-resolution image using cubic facet model. The input image is reduced by the multi-resolution and we obtain the multi-resolution images. We apply the facet model and the local maxima conditions to the multi-resolution images of each level. And then, we detect the location of the small target. We estimate that the location at the maximum of the $D_2$ which means the local maxima value of the facet model in the multi-resolution images is the location of the small target. We can detect the small target of the various size about the multi-resolution images of each level. In this paper, we experimented in the various infrared images with the small target. The method using the typical facet model applies a mask. However, the proposed method applies a mask in the multi-resolution images. We verified to vary the mask size and differ the size of the small target. The proposed algorithm can detect the location and size of the small target.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.759-769
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• 2002

Mutated forms of ras are found in many human tumors and the rate of incidence is significantly higher in colon and pancreatic cancers. The protein product from the ras oncogene is a small G-protein, $p21^{ras}{\;}(Ras)$ that is known to playa key role in the signal transduction cascade and cell differentiation and proliferation. Mutated Ras is unable to regulate itself and remains constantly activated, leading to uncontrolled cell growth. The function of Ras in signal transduction requires its location near the growth factor receptor at the cell membrane. However, Ras does not have a transmembrane domain. Ras requires farnesylation to increase its hydrophobicity and subsequent plasma membrane association for its transforming activity. This key post-translational modification is catalyzed by the enzyme Ras farnesyltransferase (FTase), which transfers a farnesyl group from farnesylpyrophosphate to the C-terminal cysteine of the Ras protein. The requirement has focused attention on FTase as a target for therapeutic intervention. Selective inhibition of FTase will prevent Ras protein from association with the plasma membrane, leading to a disruption of oncogenic Ras function.

• Journal of electromagnetic engineering and science
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• v.3 no.2
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• pp.79-85
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• 2003

In this paper, we investigated the degree of compensation for distorted optical pulse of wavelength division multiplexed(WDM) channel with initial frequency chirp generated in optical transmitter. The WDM channel signal distortion is due to chromatic dispersion, self phase modulation(SPM) and cross phase modulation(XPM) in fiber. The considered system is 3 ${\times}$ 40 Gbps intensity modulation direct detection(IM/DD) WDM transmission systems, which adopted mid-span spectral inversion(MSSI) as compensation method. We confirmed that the effect of initial frequency chirp on compensation for signal distortion due to a SPM is gradually decreased as a dispersion coefficient of fiber becomes gradually small. But, in the aspect of a compensation for signal distortion due to both SPM and XPM, the effect of initial frequency chirp on compensation is gradually decreased as a dispersion coefficient of fiber becomes gradually large.

• ETRI Journal
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• v.26 no.6
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• pp.605-614
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• 2004

In this paper, we investigate array calibration algorithms to derive a further improved version for correcting antenna array errors and RF transceiver errors in CDMA smart antenna systems. The structure of a multi-channel RF transceiver with a digital calibration apparatus and its calibration techniques are presented, where we propose a new RF receiver calibration scheme to minimize interference of the calibration signal on the user signals. The calibration signal is injected into a multi-channel receiver through a calibration signal injector whose array response vector is controlled in order to have a low correlation with the antenna response vector of the receive signals. We suggest a model-based antenna array calibration to remove the antenna array errors including mutual coupling errors or to predict the element patterns from the array manifold measured at a small number of angles. Computer simulations and experiment results are shown to verify the calibration algorithms.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.270-273
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• 2000

We have fabricated and analyzed photodiodes for optical link with Si pin structures. As the results of experiment, the web patterned photodiode(type C) with $p^{+}$-guard ring showed low junction capacitance of 6~7 pF at $V_{R}$=-5V and high separation ability for optical signal(dark current : $\leq$ 5 nA, optical signal current : $\geq$ 340 nA) due to the small effective $p^{+}$-n junction area and the expanded electric field region. The fabricated Si pin photodiode can be applicable for detecting an optical signal with the wavelength of about 660~670 nm. It can also be integrated with the twin well CMOS structure to develope an one chip based optical receiver IC. IC.C.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.12
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• pp.46-52
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• 1991

A new signal process circuit using two ISFETs as the input devices of the MOS differential amplifier stage for an ISFET biosensor has been developed. One chip integration of the newly developed signal process circuit, ISFETs and a Pt quasi-reference electrode has been carried out according to modified LOCOS p-well CMOS process. The fabricated chip showed gains of 0.8 and 1.6, good liniarity in the input-output relationship and very small power dissipation, 4mW. The chip was applied to realize a urea sensor by forming an immobilized urease membrane, using lift-off technique. on the gate of an ISFET. The urea sensor chip showed stable responses in a wide range of urea concentrations.

• Journal of Ocean Engineering and Technology
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• v.32 no.1
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• pp.62-67
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• 2018

A wave buoy commonly used for measurements in marine environments is very useful for measurements on the sea surface wind and waves. However, it is constantly exposed to external forces such as typhoons and the risk of accidents caused by ships. Therefore, the installation and maintenance charges are large and constant. In this study, we developed a system for monitoring the sea surface wind using marine radar to provide spatial and temporal information about sea surface waves at a small cost. The essential technology required for this system is radar signal processing. This paper also describes the analytical process of using it for monitoring the sea surface wind. Consequently, developing this system will make it possible to replace wave buoys in the near future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1413-1421
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• 1993

It is possible to weaken the undesirable effect of a bounded control input signal to the plant and done by setting up an additional correction loop which compensates for the suppresed portion of the control input signal. The design and analysys of stability of state controller is used by the Kalman-Szego-Lemma and as the result of this method is made possible to take advantage of the control input to the plant even for small error signals.

• Journal of Power Electronics
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• v.10 no.3
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• pp.306-312
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• 2010

In this paper, the design of an optimum single input Fuzzy controller for application in dc to ac converters is presented. Contrary to conventional Fuzzy controllers, the proposed controller has a smaller number of rules and tuning parameters but is capable of performing identically to a conventional controller. These benefits lead to a simpler controller design. The controller is designed as a PI controller for small-signal disturbances. However, for optimum large-signal performance, heuristic tuning is used. The tuning is less complicated and hence optimum large-signal performance is achievable. The system is simulated and a hardware prototype was developed for comparison purposes.