• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3010-3012
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• 2005

Orthogonal frequency division multiplexing (OFDM) 시스템은 높은 peak-to-average power ratio(PAR) 문제를 가진다. 일반적으로, partial transmit sequence(PTS) 기법을 이용하여 최적의 PAR 감소 성능을 얻기 위해서는 나눈 부블록의 수와 위상 요소 (rotation factor)에 관한 모든 탐색을 해야 한다. 나눈 부블록 수와 factor 수가 많을수록 PAR 감소 성능은 그 만큼 증가하지만, 그에 비례하여 복잡성과 계산량 또한 지수적으로 증가하여 송신기에서의 시간지연과 전력소비를 초래한다. 따라서, PAR 감소 성능을 낮추면서 복잡성 또한 줄일 수 있는 방법이 요구된다. 하지만, 성능과 계산의 복잡성 사이에는 트레이드오프가 존재하여, 두가지를 동시에 줄이는 것은 매우 어렵다. 본 논문에서는, 성능과 복잡성 사이의 최적의 트레이드오프에 대해 분석하고, 제안한 PTS 기법의 성능을 기존의 복잡한 PTS 기법과 비교한다.

• Biomedical Science Letters
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• v.10 no.4
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• pp.507-514
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• 2004

The Pseudomonas aeruginosa isolated from the clinical specimens has a mutation on the QRDR (quinolone resistance determining region). There were obvious mutations in both gyrA and parC gene which are major targets of quinolone. Simultaneous mutations were found two sites or more on these genes in all of ten strains. GyrB or parE gene had only silent mutation without converted amino acids. We confirmed that P. aeruginosa from clinical specimens exhibited decreased sensitivity to fluroquiolone due to changed Thr-83→lle and Asp-87→Asn types on gyrA and altered Ser-87→Leu type on parC. This is the first finding that a new Met-93→Thr type on parC as well as mutations on gyrB or parE genes differed from existing patterns. This study showed more mutations of gyrA rather than parC, suggesting that change of Type Ⅳ topoisomerase is more serious than that of type Ⅱ (DNA gyrase).

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.2
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• pp.112-119
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• 2016

Many studies have been conducted on the performance of a passive autocatalytic recombiner (PAR), but not many have focused on the locations where the PAR is installed. During a severe accident in a nuclear reactor containment, a large amount of hydrogen gas can be produced and released into the containment, leading to hydrogen deflagration or a detonation. A PAR is a hydrogen mitigation method that is widely implemented in current and advanced light water reactors. Therefore, for this study, a PAR was installed at different locations in order to investigate the difference in hydrogen reduction rate. The results indicate that the hydrogen reduction rate of a PAR is proportional to the distance between the hydrogen induction location and the bottom wall.

• YAKHAK HOEJI
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• v.47 no.5
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• pp.325-330
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• 2003

Solanum melongena L. (Solanaceae) has anti-oxidant, analgesic, and hypolipidemic effects. We previously showed that Solanum melongena (SM) aqueous extract inhibits mast cell-mediated allergic reactions. The activation of protease-activated receptor-2 (PAR-2) induces acute inflammation in rat hindpaw. In the present study, we investigated the effects of the SM aqueous extract on mouse paw edema induced by PAR2 agonists. Trypsin or trans-cinnamoyl-LIGRLO-NH$_2$ (tc-NH$_2$), PAR-2 agonists, was injected into the hind paw of mice to induce paw edema. SM aqueous extract (1, 5, 10, and 100 mg/kg) was orally administered 1 hr before induction of paw edema. SM aqueous extract (5, 10, and 100 mg/kg) significantly inhibited both paw edema and vascular permeability in the dose-dependent manner. Furthermore, SM aqueous extract (10 mg/kg) significantly inhibited PAR-2 agonist-induced myeloperoxidase (MPO) activity and tumor necrosis factor (TNF)-$\alpha$ expression in paw tissue compared to that of saline. These results suggest that SM aqueous extract may be useful for treatment of PAR-2-mediated inflammation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4C
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• pp.230-238
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• 2005

An orthogonal frequency division multiplexing (OFDM) system consists of a number of independently modulated subcarriers and, thus, a high peak-to-average power ratio (PAR) can occur when the subcarriers are added coherently. The high PAR brings such disadvantages as an increased complexity of the analog-to-digital (ADC) and digital-to-analog (DAC) converters and a reduced efficiency of the radio frequency (RF) power amplifier. In this paper, we propose a novel PAR reduction scheme called selective mapping of partial tones (SMOPT). The SMOPT scheme has a reduced complexity, lower sensitivity to peak reduction tones (PRT) positions, and a shorter processing time as compared with the conventional tone reservation (TR) scheme. The performance of the SMOPT scheme is analyzed based on the IEEE 802.1la wireless local area network(WLAM) physical layer model. Numerical results show that the SMOPT scheme outperforms the TR scheme under various scenarios.

• Tuberculosis and Respiratory Diseases
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• v.74 no.6
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• pp.264-268
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• 2013

Background: Idiopathic pulmonary fibrosis (IPF) is a lethal pulmonary fibrotic disease. In general, the exaggerated activation of the coagulation cascade has been observed during initiation or maintenance of the fibrotic disease. In our recent study, immunohistochemical expression of protease-activated receptor-2 (PAR-2), which plays a key role in coagulation cascade, was observed in surgical specimen of IPF patients, and associated with poor clinical outcome. The aim of this study was to evaluate the overexpression of PAR-2 in inflammatory cells from peripheral blood and bronchoalveolar lavage fluid in IPF patients. Methods: From May 2011 to March 2012, IPF patients and controls were enrolled in Seoul National University Hospital. Peripheral blood and bronchoalveolar lavage fluid were collected for analysis of PAR-2 expression. Flow cytometry and reverse transcription polymerase chain reaction were used for PAR-2 receptor and mRNA assessment. Results: Twelve IPF patients and 14 controls were included in this study. Among them, flow cytometry analysis was conducted from 26 peripheral blood (patient group, 11; control group, 13) and 7 bronchoalveolar lavage fluid (patient group, 5; control group, 2). The expression of PAR-2 receptor was not different between patient and control groups (p=0.074). Among all 24 population, PAR-2 mRNA assessment was performed in 19 persons (patient group, 10; control group, 9). The mRNA expression of PAR-2 was not significant different (p=0.633). Conclusion: In IPF patients, PAR-2 receptor and mRNA expression were not different from control group.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.489-495
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• 2014

Protease-activated receptor (PAR)-2 is expressed in endothelial cells and vascular smooth muscle cells. It plays a crucial role in regulating blood pressure via the modulation of peripheral vascular tone. Although some reports have suggested involvement of a neurogenic mechanism in PAR-2-induced hypotension, the accurate mechanism remains to be elucidated. To examine this possibility, we investigated the effect of PAR-2 activation on smooth muscle contraction evoked by electrical field stimulation (EFS) in the superior mesenteric artery. In the present study, PAR-2 agonists suppressed neurogenic contractions evoked by EFS in endothelium-denuded superior mesenteric arterial strips but did not affect contraction elicited by the external application of noradrenaline (NA). However, thrombin, a potent PAR-1 agonist, had no effect on EFS-evoked contraction. Additionally, ${\omega}$-conotoxin GVIA (CgTx), a selective N-type $Ca^{2+}$ channel ($I_{Ca-N}$) blocker, significantly inhibited EFS-evoked contraction, and this blockade almost completely occluded the suppression of EFS-evoked contraction by PAR-2 agonists. Finally, PAR-2 agonists suppressed the EFS-evoked overflow of NA in endothelium-denuded rat superior mesenteric arterial strips and this suppression was nearly completely occluded by ${\omega}$-CgTx. These results suggest that activation of PAR-2 may suppress peripheral sympathetic outflow by modulating activity of $I_{Ca-N}$ which are located in peripheral sympathetic nerve terminals, which results in PAR-2-induced hypotension.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.643-646
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• 2014

Objective: This study aimed to explore the expression of tissue factor (TF), protease activated receptor-2 (PAR-2), and matrix metalloproteinase-9 (MMP-9) in the MCF-7 breast cancer cell line and influence on invasiveness. Methods: Stable MCF-7 cells transfected with TF cDNA and with TF ShRNA were established. TF, PAR-2, and MMP-9 protein expression was analyzed using indirect immunofluorescence and invasiveness was evaluated using a cell invasion test. Effects of an exogenous PAR-2 agonist were also examined. Results: TF protein expression significantly differed between the TF cDNA and TF ShRNA groups. MMP-9 protein expression was significantly correlated with TF protein expression, but PAR-2 protein expression was unaffected. The PAR-2 agonist significantly enhanced MMP-9 expression and slightly increased TF and PAR-2 expression in the TF ShRNA group, but did not significantly affect protein expression in MCF-7 cells transfected with TF cDNA. TF and MMP-9 expression was positively correlated with the invasiveness of tumor cells. Conclusion: TF, PAR-2, and MMP-9 affect invasiveness of MCF-7 cells. TF may increase MMP-9 expression by activating PAR-2.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1181-1185
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• 2005

A combining of MIMO signal processing with OFDM is regarded as a promising solution of enhancing the performance of next generation wireless system. Therefore, in this paper, an OFDM-based wireless system employing layered space-time architecture is considered for a high-rate transmission. In the MIMO-OFDM system, we evaluate the PAR performance using the SLM approaches. The investigated SLM scheme for MIMO-OFDM signals selects the transmitted sequence with lowest average PAR over all transmitting antennas and retrieves the side information very accurately at the expense of a slight degradation of the PAR performance. The low probability of false side information can improve the overall detection performance of the MIMO-OFDM system with erroneous side information compared to the ordinary SLM approache, respectively. Also, we provide closed form of the average BER performance in MIMO-OFDM system using analytic approach.

• Ocean Science Journal
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• v.41 no.4
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• pp.235-244
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• 2006

Determining 'photosynthetically active radiation' (PAR) is a key part of calculating phytoplankton productivity in a biogeochemical model. We explore the daily and seasonal variability in the ratio of PAR irradiance to total irradiance that occurred at Ieodo Ocean Research Station (IORS) in the East China Sea under clear-sky conditions in 2004 using a simple radiative transfer model (RTM). Meteorological data observed at IORS and aerosol optical properties derived from Aerosol Robotic Network observations at Gosan are used for the RTM. Preliminary results suggest that the use of simple PAR irradiance-ratio values is appropriate in calculating phytoplankton productivity as follows: an average of $0.44\;({\pm}0.01)$ in January to an average of $0.48\;({\pm}0.01)$ in July, with average daily variabilities over these periods of about $0.016\;({\pm}0.008)$ and $0.025\;({\pm}0.008)$, respectively. The model experiments demonstrate that variations in the major controlling input parameters (i.e. solar zenith angle, precipitable water vapor and aerosol optical thickness) cause PAR irradiance ratio variation at daily and seasonal timescales. Further, increases (>0.012) in the PAR irradiance ratio just below the sea-surface are positively correlated with high solar zenith angles and strong wind stresses relative to those just above the sea-surface.