• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.458-463
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• 2005

OFDM communication system is effective for the high data rate transmission in the frequency selective fading channel. Since OFDM has high PAPR, OFDM signal may be distorted by the nonlinear HPA. In this paper, we propose an combined SLM and PTS method for reducing the PAPR in OFDM communication system. Proposed method increased some system complex in comparison with exiting method. But we made sure of high efficiency in the case of reducing the PAPR. As a result of using the 16-QAM modulation and increasing the carrier number in the SLM, PTS method and the SLM-PTS combined method, SLM-PTS combined method is more an effective method of reducing 3.5 dB PAPR than exiting OFDM system when this method is M, L=3, D=128, 256 in 10-3 BER.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4561-4568
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• 2011

In this paper, carrier comparison PWM method for voltage control of Vienna rectifier is discussed. In general, in industrial and communications applications, the two-level rectifier is used. However, this two-level rectifier has the limit of high THD and low efficiency. So, the studies of three-level rectifier has been carried out so far, and the Vienna rectifier circuit is the representative. The space vector pulse width modulation(SVPWM) method is generally used for Vienna rectifier, in which voltage vectors and duration time are calculated from the voltage reference. However, this method require very sophisticated and complex calculations, so realizing this method by software is very difficult. To overcome this disadvantage, simple carrier comparison PWM method for Vienna rectifier is proposed which is modified from the carrier comparison method for 3 level inverter. Furthermore, to verify the usefulness of the Vienna rectifier carrier comparison PWM the simulation and experiment are carried out.

• Korean Journal of Clinical Laboratory Science
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• v.40 no.1
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• pp.31-40
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• 2008

Despite of the importance of the primordial follicle (PMF) recruitment, factors and mechanisms for process are poorly understood. To evaluate expression and role of the follicular transition from PMF to PMF/primary follicles (PMIF) in the present study, we evaluated expression of lats1, lats2, cyclin A1, and cyclin A2 mRNA and protein, and elucidated and role of lats1-cyclin A in the follicular transition from PMF to PRIF. To analysis of differential expression in PMF and PMIF, each stage follicles were collected by day1 and day5 of immuno-compromised rats (ICR) and analyzed by real-time PCR for the genes. For localization of mRNAs and proteins of the genes, in situ hybridization and immunohistochemistry were performed. We confirmed that the lats1, lats2, cyclin A1, and cyclin A2 mRNA were more expressed in PMF than PMIF. Localization of the four genes expression were observed in nuclei of oocytes from the arrested primordial, and in the surrounding granulosa cells of the growing follicles. The mRNA expressions were gradually decreased with follicular development. From immunohistochemistry studies, Cyclin A1 protein expression were observed in oocyte cytoplasmas of early stage follicles, while observed in granulose cells and oocyte nucleoli during growing follicles. This study suggested that the presence of lats gene family might perform negatively regulation of cell proliferation by modulation of the CDC2/Cyclin A complex activity. lats-cyclin A genes in oocytes of the early stage follicles might play a role in the meiotic cell cycle arrest of the primary oocytes at the primordial follicle stage as well as the follicular growth.

• Biomolecules & Therapeutics
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• v.5 no.4
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• pp.325-330
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• 1997

Methanol extract of G. elata inhibited the binding of [/sup 3/H]Rol5-1788, a selective benzodiazepine receptor antagonest, to benzodiazepine receptor of rat cortices. Saturation experiments followed by Scatchard analysis of the results showed that the inhibition of [sub 3/H]Ro15-1788 binding by G. dlata. appeared to be com-petitive. These competitive inhibiton of the butanol fraction was observed to be higher than the methanol extract. Methanol extract of G. efara inhibited a [sub 3/H]flunitrazepam, a selective benzodiazepine receptor agonist, binding to benzodiazepine receptor. GABA significantly enhanced the inhibition of [/sub 3/H]flunitrazepam binding by G. elata, and these "positive GABA shift" supported the strong possibility of agonestic activity to benzodiazepine receptor Butanol fraction was observed to be higher than crude extract by methanol in an agonistic activity to benzodiazepine receptor, furthermore enhanced the binding of [sub 3/H]SR95531 to GABA receptor. Butanol fraction of G. elata significantly diminished the pentylenetetrazole-induced lethality of mice. From these results, it can be concluded that substance or substances with neurochemical properties characteri- stic of a benzodiazepine receptor agonist may be important components, and contribute to the anticonvulsant property of G. elata.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.159-169
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• 2004

This is a proposal to probe local part of the interplanetary dust (IPD) cloud complex and retrieve mean volume emissivity of the local IPDs at mid-infrared wavelengths. This will be done by monitoring, with Infrared Camera (IRC) aboard the ASTRO-F, the annual modulation of the zodiacal emission. In pointing mode of the ASTRO-F mission the spacecraft can make attitude maneuvering over approximately ${\pm}1^{\circ}$ range centered at solar elongation $90^{\circ}$ in the ecliptic plane. The attitude maneuvering combined with high sensitivity of the IRC will provide us with a unique opportunity observationally to take derivatives of the zodiacal emission brightness with respect to the solar elongation. From the resulting differential of the brightness over the ${\pm}1^{\circ}$ range, one can directly determine the mean volume emissivity of the local IPDs with a sufficient accuracy to de-modulate the annual emissivity variations due to the Earth's elliptical motion and the dis-alignment of the maximum IPD density plane with respect to the ecliptic. The non-zero eccentricity ($e_{\oplus}$= 0.0167) of the Earth's orbit combined with the sensitive temperature dependence of the Planck function would bring modulations of amplitude at least $3.34\%$ to the zodiacal emission brightness at mid-infrared wavelengths, with which one may determine the IPD temperature T(r) and mean number density n(r) as functions of heliocentric distance r. This will in turn fix the power-law exponent $\delta$ in the relation $T(r) = T_o(r/r_o)^{-\delta}$ for the dust temperature and v in $n(r) = n_o(r/r_o)^-v$ for the density. We discuss how one may de-couple the notorious degeneracy of cross-section, density, reference temperature $T_o$ and exponent $\delta$.

• Journal of Dental Anesthesia and Pain Medicine
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• v.17 no.3
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• pp.163-181
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• 2017

In the field of orofacial surgery, a red blood cell transfusion (RBCT) is occasionally required during double jaw and oral cancer surgery. However, the question remains whether the effect of RBCT during the perioperative period is beneficial or harmful. The answer to this question remains challenging. In the field of orofacial surgery, transfusion is performed for the purpose of oxygen transfer to hypoxic tissues and plasma volume expansion when there is bleeding. However, there are various risks, such as infectious complications (viral and bacterial), transfusion-related acute lung injury, ABO and non-ABO associated hemolytic transfusion reactions, febrile non-hemolytic transfusion reactions, transfusion associated graft-versus-host disease, transfusion associated circulatory overload, and hypersensitivity transfusion reaction including anaphylaxis and transfusion-related immune-modulation. Many studies and guidelines have suggested RBCT is considered when hemoglobin levels recorded are 7 g/dL for general patients and 8-9 g/dL for patients with cardiovascular disease or hemodynamically unstable patients. However, RBCT is occasionally an essential treatment during surgeries and it is often required in emergency cases. We need to comprehensively consider postoperative bleeding, different clinical situations, the level of intra- and postoperative patient monitoring, and various problems that may arise from a transfusion, in the perspective of patient safety. Since orofacial surgery has an especially high risk of bleeding due to the complex structures involved and the extensive vascular distribution, measures to prevent bleeding should be taken and the conditions for a transfusion should be optimized and appropriate in order to promote patient safety.

• Animal cells and systems
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• v.2 no.3
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• pp.403-410
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• 1998

The Tcf-1 (T cell specific factor-1) is a transcription factor uniquely expressed in T-lineage cells. Its expression is developmentally regulated, which is high in the specific stage of immature thymocytes, but is much lower in mature T cells. We cloned the Tcf-1 gene by subtractive hybridization and found it to be highly expressed in the thymus compared to the mRNA level in the spleen as expected. Since apoptosis occurs enormously in the thymus, we were interested in whether Tcf-1 gene expression could be regulated by such a high level of apoptotic assault. By using T cell hybridoma 70.7 cells, we induced apoptosis by incubating cells with anti-CD3 antibody in vitro. After apoptosis induction, Tcf-1 mRNA level was found to be significantly reduced compared to normal cells. Since Tcf-1 is a transcription factor for the CD3-e gene, we tested how CD3-e expression is regulated in apoptotic cells. The surface level of CD3-e protein is also down-regulated after apoptosis induction. Such a down-modulation of CD3-e protein would reduce the TCR/CD3 complex on the cell surface, which would be an important regulator for T cell apoptosis.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.47-47
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• 2003

The presenilin 1 (PS1) or PS2 is an essential component of the ${\gamma}$-secretase complex, which mediates the intramembrane proteolysis of selected type-I membrane, including the ${\beta}$-amyloid precursor protein (APP) to yield A${\beta}$. Familial Alzheimer's disease (FAD)-associated mutations in presenilins give rise to an increased production of a highly amyloidogenic A${\beta}$42. In addition to their well-documented proteolytic function, the presenilins play a role in calcium signaling. We have previously reported that presenilin FAD mutations cause highly consistent alterations in intracellular calcium signaling pathways, which include deficits in capacitative calcium entry (CCE), the refilling mechanism for depleted internal calcium stores. However, molecular basis for the presenilin-mediated modulation of CCE remains to be elucidated. In the present study, whole-cell patch clamp method was used to identify a specific calcium-permeable ion channel current(s) that is responsible for the CCE deficits associated with FAD-linked PS1 mutants. Unexpectedly, both voltage-activated and conventional store depletion-activated calcium currents I(CRAC), were absent in HEK293 cells, which were stably transfected either with wild-type or FAD mutant (L286V, M146L, and delta E9) forms of PS1. Recently, magnesium-nucleotide-regulated metal cation current, or I(MagNum), has been described and appears to share many common properties with I(CRAC) including calcium permeability and inhibitor sensitivity (e.g. 2-APB). We have detected I(MagNum) in all 293 cells tested. Interestingly, FAD mutant 293 cells developed only about half of currents compared to PS1 wild type cells.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.10
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• pp.1-9
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• 1999

In this paper, a subblock partition scheme for reduction of computational complexity in partial transmit sequence which reduces the peak-to-average power ratio in orthogonal frequency division multiplexing (OFDM) is proposed. In this scheme, complex signals are assigned into partial subbands randomly and signals in a partial subband are duplicated and concatenated repetitively to make a subblock. By modulation of active subbands which have almost interleaved pattern, computational complexity can be reduced. As results of computer simulation, the proposed shows almost same peak to average power ratio reduction performance as compared to the conventional one. However, computational complexity required to transmit a partial transmit sequence OFDM symbol has been reduced extensively.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.219-225
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• 2014

The purpose of this paper is to control of the low-speed, high-precision PMSM 2-axes pitch/turning. In this paper, apply the PAM-PWM inverter for it. However, The PAM-PWM inverter, control algorithms and hardware is complex. But it is possible to improve the performance in the low-speed operation can reduce the effect of the PWM ripple and Dead Time of inverter by applying suitable DC-bus voltage control. The direct driver PMSM(Permanent Magnet Synchronous Motor) configured to vector control part, PAM control part and the other controller. The vector control part includes PI current, speed control, additional space vector modulation. PAM control part has to have PI voltage controller and P current controller for DC-bus voltage control. Besides, the motor position estimator, the speed estimator and the counter electromotive force and Dead Time Compensation are added. With this arrangement, PMSM was driven with a low pole pitch/turning by performing the current control to the current command or torque command is the paper. As a result, it was possible to minimize the disturbance component that appears in the drive in proportion to the DC voltage magnitude. The use of a hydraulic drive method for a two-axis bubble column is a typical tank. When using the PWM PAM inverter driver is in the turret can be driven by high-precision, low vibration, low noise compared to the hydraulic drive may contribute to the computerization of the turret.