• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.197-204
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• 2013

In this paper, we propose a new method for artificial bandwidth extension of narrow-band signal in frequency domain. In the proposed method, a narrow-band signal is decomposed into excitation signal and spectral envelope, which are extended independently in frequency domain. The excitation signal is extended such that low-band harmonic structure is maintained in high band, and the spectral envelope is extended based on sub-band energy using NMF. Finally, the spectral phase is determined based on signal correlation between frames in time domain, resulting in the final wide-band signal. The subjective evaluation verified that the wide-band signal generated by the proposed method has a higher quality than the original narrow-band signal.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2615-2618
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• 2009

Double rectangular patch with 4-bridges is investigated for solution of IEEE 802.11b/g (2.4 GHz) and 802.11a (5.5 GHz). Rectangular patch for 5.5 GHz frequency band is printed on the PCB substrate and connected to another rectangular patch for 2.4 GHz frequency band with 4-bridges to obtain dual band operation in an antenna element. 4-bridges can modify the desired frequency band from its original frequency band by changing its width. Gain of 2.4 GHz patch is 5 dBi and 5.5 GHz patch is 3.7 dBi at ${\theta}=0^{\circ}$.

• Journal of Korean Academy of Nursing
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• v.38 no.4
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• pp.503-512
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• 2008

Purpose: This study was to identify the effects of Nei-Guan accupressure using a wrist band on postoperative nausea and vomiting after middle ear surgery. Methods: The study design was a nonequivalent control group non-synchronized posttest design. Forty patients were assigned into two groups of 20 patients, the wrist band group and the control group. In the wristband group, acupressure was applied with a wrist band on the P6 point at both wrists from 30 min before to 24 hr after anesthesia. Results: The 1st hypothesis 'Applied wrist band groups will have a greater reduction in the nausea & vomiting grades by INVR than the control group' was accepted (t=2.303, p=.028). The 2nd hypothesis 'The Applied wrist band groups will have a greater reduction in the occurrence of nausea & vomiting than the control group' was partly accepted. The 3rd hypothesis 'The applied wrist band group will have a greater reduction in injection of antiemetics for 24 hr. post anesthesia than the control group' was rejected. Conclusion: Acupressure on the P6 point using a wrist band is effective to alleviate nausea for middle ear surgery patients.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.3
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• pp.245-251
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• 2013

The effect of band-to-band tunneling (BTBT) leads to an obvious increase of the leakage current of junctionless (JL) transistors in the OFF state. In this paper, we propose an effective method to decline the influence of BTBT with the example of n-type double gate (DG) JL metal-oxide-semiconductor field-effect transistors (MOSFETs). The leakage current is restrained by changing the geometrical shape and the physical dimension of the gate of the device. The optimal design of the JL MOSFET is indicated for reducing the effect of BTBT through simulation and analysis.

• Journal of electromagnetic engineering and science
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• v.16 no.3
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• pp.164-168
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• 2016

A dual-band through-the-wall imaging radar receiver for a frequency-modulated continuous-wave radar system was designed and fabricated. The operating frequency bands of the receiver are S-band (2-4 GHz) and X-band (8-12 GHz). If the target is behind a wall, wall-reflected waves are rejected by a reconfigurable $G_m-C$ high-pass filter. The filter is designed using a high-order admittance synthesis method, and consists of transconductor circuits and capacitors. The cutoff frequency of the filter can be tuned by changing the reference current. The receiver system is fabricated on a printed circuit board using commercial devices. Measurements show 44.3 dB gain and 3.7 dB noise figure for the S-band input, and 58 dB gain and 3.02 dB noise figure for the X-band input. The cutoff frequency of the filter can be tuned from 0.7 MHz to 2.4 MHz.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.422-425
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• 2008

TerraSAR-X is new radar satellite operated at X-band, multi polarization, and multi beam mode. Compared with C-band or L-band SAR, the X-band system inherently suffers from more temporal decorrelation, but is more sensitive to surface deformation monitoring due to short wavelength (3.1 cm) and high spatial resolution (1m-3m). It is generally expected that sensitivity to estimate surface movement using TerraSAR-X will be increased by the factor of 10, compared to current C-band system with low spatial resolution such as ERS-2, Envisat. Many urban areas are experiencing land subsidence due to water, oil and natural gas withdrawal, underground excavation, sediment compaction, and so on. Monitoring of surface deformation is valuable for effectively limiting damage areas. In addition high accuracy and spatially dense subsidence map can be achieved by X-band InSAR observation, promoting identification and separation of various subsidence processes and leading to enhanced understanding via mechanical modeling. In this study we will introduce some initial InSAR results using new TerraSAR-X SAR data for surface deformation monitoring.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.147-152
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• 1996

The 2,4-D + BA combination in MS medium showed high regenerating ability and induced compact callus from leaf and petiole segments of three strawberry cultivars, 'Bokyo', 'Suhong', whereas the NAA + BA combination resulted in friable callus. Band of RAPD products obtained with primer 212 from the callus was different from the band of mother plant when callus induced from leaf segment of 'Suhong' cultivar was maintained in MS medium containing NAA or BA for 8 months. The RAPD bands obtained from mother plants of 'Bokyo' and 'Yeobong' were different from that of callus maintained in the presence of MS liquid medium containing 2,4-D(0.2 mg/$\ell$) subcultured every two weeks for 6 months(12 subcultures).

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.11
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• pp.89-94
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• 2011

In this paper, we developed the W-band MMIC low noise amplifier for the millimeter-wave seeker using the tuner system. The MHEMT devices for MMIC LNA exhibited DC characteristics with a drain current density of 692mA/mm, an extrinsic transconductance of 726mS/mm. The current gain cutoff frequency(fT) and maximum oscillation frequency($f_{max}$) were 195GHz and 305GHz, respectively. The fabricated W-band low noise amplifier represented S21 gain of 7.42dB at 94 GHz and noise figure of 2.8dB at 94.2 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1065-1072
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• 2012

In this paper, the method of design of the waveguide band-pass filter and limiter in radar system is proposed. First, we design a self-resonant iris, which can behave as a band-pass filter by mounting the PIN diode on the iris. When low power microwave is incident on the proposed element, the element behaves as a band-pass filter. Under a high power microwave condition, however, the element behaves as a limiter having wide band stop characteristics. The fabricated element has a pass band with -0.7 dB insertion loss at 10 GHz under the low power condition and isolation about 25 dB under the high power condition.

• Journal of The Korean Astronomical Society
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• v.45 no.1
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• pp.7-17
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• 2012

Y-band is a broad passband that is centered at ~1 ${\mu}m$. It is becoming a new, popular window for extragalactic study especially for observations of red objects thanks to recent CCD technology developments. In order to better understand the general characteristics of objects in Y-band, and to investigate the promise of Y-band observations with small telescopes, we carried out imaging observations of several extragalactic fields, brown dwarfs, and high redshift quasars with Y-band filter at the Mt. Lemmon Optical Astronomy Observatory and the Maidanak observatory. From our observations, we constrain the bright end of the galaxy and the stellar number counts in Y-band. We also test the usefulness of high redshift quasar (z >6) selection via i - z - Y color-color diagram, to demonstrate that the i - z - Y color-color diagram is effective for the selection of high redshift quasars even with a conventional optical CCD camera installed at a 1-m class telescope.