• The Journal of the Acoustical Society of Korea
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• v.33 no.4
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• pp.255-261
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• 2014

This paper presents an underwater acoustic communication with nonlinear chirp modulation. The information is carried by the carrier amplitude, frequency or phase in the most common underwater acoustic communications. However, the proposed method includes the information within frequency variation of carrier wave for a symbol. Especially, as carrier wave the hyperbolic frequency modulated signal, one of the nonlinear chirp signal, is used and it is robust in the Doppler channel. The proposed method was analyzed and compared to conventional method by simulation. When the doppler shift existed, the error probability of the proposed method is reduced by 5~12 % than conventional method with linear frequency modulated signal. Sea trial was performed to analyze the performance of the proposed method.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.2
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• pp.107-112
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• 2011

Several developed countries have been developing their own satellite navigation systems, such as Europe's Galileo, China's BEIDOU, and Japan's QZSS, to cope with clock errors and signal vulnerabilities of GPS. In addition, modernization of Loran, eLoran, for GPS backup has been conducted. In Korea, a dependent navigation system has been required and for GPS backup, the need for utilization of time synchronization infrastructure through the modernization of Loran has been raised. Loran signal uses 100Khz groundwave. A significant factor limiting the ranging accuracy of the Loran signal is the ASF arising from the fact that the groundwave signal is likely to propagate over paths of varying conductivity and topography. Thus, an ASF compensation method is very important for Loran and eLoran navigation. This paper introduces the propagation delay model and then compares and analyzes the estimations from the propagation delay model and measured ASFs.

• Toxicological Research
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• v.17 no.3
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• pp.215-223
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• 2001

Cadmium is an ubiquitous toxic metal and chronic exposure to cadmium results in the accumulation of cadmium in the liver and kidneys. In contrast, acute exposure leads to damage mainly in the liver. Apoptosis induced by cadmium has been shown in many tissues in vivo and in cultured cells in vitro. However, the molecular mechanism of cadmium-induced apoptosis is not clear in hepatocyte. To investigate the induction of apoptosis in the hepatocyte, we used mouse hepatoma cell line, Hepalclc7 cells, and analysed the molecules that involved in cadmium-induced apoptosis. Cadmium induced the genomic DNA fragmentation, PARP cleavage, and activation of caspase-3 like protease. Caspase-9 cysteine protease was activated in a time-dependent manner but caspase-8 cysteine protease was not significantly activated in cadmium-treated Hepalclc7 cells. Cadmium also induced mitochondrial dysfunction including cytochrome c release from mitochondria, change oj mitochondrial membrane potential tranition, and tranlocation of Bax Protein into mitochondria. These results strong1y indicated that the signal Pathway of apoptotic death in cadmium-treated Hepalclc7 cells is modulated by caspase cascade via mitochondria.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.555-563
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• 2018

Barley has nutritional benefits due to its high dietary fiber content; therefore, the intake of whole barley grains is recommended. However, barley is often consumed in the fermented form because of the improved texture and digestibility. The present study was designed to elucidate the intracellular signaling pathway for macrophage activation by the polysaccharide BF-CP from fermented barley. BF-CP is a neutral polysaccharide, composed of neutral sugars, including glucose (70.7%), xylose (11.4%), and arabinose (9.0%). BF-CP exhibited macrophage-stimulatory activity by inducing the production of interleukin (IL)-6, tumor necrosis factor $(TNF)-{\alpha}$, and nitric oxide in RAW 264.7 macrophages. Further, BF-CP treatment strongly increased the IL-6 and $TNF-{\alpha}$ gene expression in a concentration-dependent manner. Signal transduction experiments using immunoblotting showed that BF-CP phosphorylated mitogen-activated protein kinases (MAPKs), such as c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38, and nuclear factor $(NF)-{\kappa}B$, in RAW 264.7 cells in a concentration-dependent manner. These results suggest that BF-CP activates the macrophages via MAPK and $NF-{\kappa}B$ pathways, and also induces an increase in the production of cytokines.

• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1152-1156
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• 2007

The Camella japonica flower(CJF) extract was studied for their anti-angiogenenic and anti-cell adhesion effect. CJF-extract inhibited the tube formation on human umbilical vein endotherial cells(HUVEC) with butanol extract by 70.2%, acetone extract by 54.2%, ethyl acetate extract by 37.0%, chloroform extract by 21.2%. Cell adhesion molecules were effectively suppressed at different concentration of CJF at 50, 100, 200 ug/well such as for intercellular adhesion molecule(ICAM) by 5.9%, 29.4% and 52.9%, for vascular cell adhesion molecule(VCAM) by 12.5%, 43.8% and 62.5%, for E-selectin by 7.1%, 21.4% and 35.7%, respectively. Signal molecules of vascular endotherial growth factor receptor 2(VEGFR2), ${/beta}$-catenin and PI3K are inhibited by different concentration of CJF at 10, 20 and 30 ${\mu}g/mL$ with western blot. Angiogenesis will be inhibited with suppressing NF-kB molecule resulted in signal molecules blocked by CJF. CJF will be useful materials for treatment of angiogenesis related diseases such as cancer, metastasis, rheumathioid arthritis and obesity.

• KSBB Journal
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• v.22 no.4
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• pp.249-254
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• 2007

Anti-angiogenesis and anti-cell adhesion effects were investigated with different dose of Camellia japonica leaf (CJL) extract for applying anti-cancer, anti-metastasis and anti-obesity. Cytotoxicity on HUVECs was very low at 200 ug/mL of CJL-extract. Anti-angiogenic ratio at increasing dose of 1.5 ug/mL, 3.0 ug/mL, 15 ug/mL and 30 ug/mL was showed 30.7%, 38.5%, 53.8%, and 70.0%, respectively. Also, anti-cell adhesion effect at concentration of $50{\mu}g{/well},\;100{\mu}g{/well}\;and\;200{\mu}g{/well}$ was expressed on E-selectin by 46.7%, 66.7%, and 86.76%, on VCAM-1, 23.0%, 61.5%, and 84.6%, and on ICAM-1, 11%, 55.5%, and 88.8%, respectively. For inquiring anti-angiogenesis mechanism, when western blot was performed with different dose of CJL extract, signal molecules of VEGFR-2, $\beta$-catenin and PI3-K were suppressed. As the signal transduction from VEGFR-2, $\beta$-catenin and PI3-K to NF-${\kappa}$B was interupted, angiogenesis could not be occurred causing not activated NF-kB. C. japonica leaf (CJL) is a useful herb for developing therapeutics of angiogenesis related diseases such as cancer, metastasis, rheumathioid arthritis and obesity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.820-829
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• 2000

In this paper, DSPA(Dynamic Signalling Period Allocation) algorithm that has been proposed by the authors for MAC(Medium Access Control) protocols in W-ATM(Wireless Asynchronous Transfer Mode) is applied to mixed traffic conditions composed of various service classes. We investigate the bandwidth utilization efficiency and quality of service(QoS) fulfillment by the DSPA algorithm used in W-ATM MAC protocols. Simulation results indicate that the DSPA algorithm significantly increases the throughput of the system with the minimum control overhead. Moreover, QoS of each service class is well satisfied by proper and fair channel allocation to different service classes according to their requirements.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.12
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• pp.1117-1124
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• 2013

As the recently soaring wireless traffic, small-cell techniques have been actively studied in order to support such a wireless demand for cellular wireless networks. This paper focuses on the inter-cell interference neutralization to resolve the main barrier for implementing small-cell cellular networks. Assuming that each message is delivered to the final destination by the help of base stations or relays, ergodic interference neutralization is proposed, which exploits the time-varying nature of wireless channels. The previous approach based on amplify-and-forward (AF) suffers from severe performance degradation in the low signal-to-noise (SNR) regime due to noise amplification. On the other hand, the proposed interference neutralization based on recently developed compute-and-forward (CF) fixes such a problem and improves the performance in the low SNR regime.

• Journal of the Korea Society of Computer and Information
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• v.29 no.5
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• pp.67-74
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• 2024

As the number of coffee shops increases, many people are studying or working at coffee shops. Coffee shop operators have been required to analyze customer visits due to customer turnover and profit problems. Methods such as image analysis, QR code authentication, and Bluetooth beacon have been proposed for these statistics and analysis. However, it is difficult to use due to problems such as invasion of privacy and low accuracy. Therefore, in this study, to solve these problem and provide more accurate in-store congestion information, we propose a crowding measurement method of coffee shop using high frequency signal. There is an advantage in that a high frequency signal replaces the Bluetooth signal, and the transmission range of the signal is limited to the store, thereby increasing the accuracy of the method. To verify the performance of the proposed system, we conducted a comparative experiment with a Bluetooth based system, and as a result, the proposed method showed lower misrecognition rate. Thus, the proposed method will be an effective useful service for providing information on crowding at coffee shops and processing statistics.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.95-95
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• 2003

Inositol은 세포의증식 및 정보전달과정에 관여하는 phosphatidylinositol (PI)의 구성성분으로서 중요한 세포내 기능을 수행한다. P1는 세포내에서 특이적 인산화효소에 의하여 Pl4-phosphate(PIP), Pl4,5-phosphate($PIP_2$)로 변환되며 PIP$_2$는 phospholipase C(PLC)에 의하여 세포내 second messengers인 1,2-diacylglycerol (DAG)와 inositol 1,4,5-triphosphate ($IP_3$)로 변환된다. 이렇게 생산된 DAG와 IP3는 각각 protein kinase C의 활성과 $Ca^{2++}$의 동원에 관여하여 다양한 세포내 신호전달에 관여하는 것으로 보고되고 있다. 또한 mouse에서 $IP_3$의 작용에 의한 $Ca^{2++}$의 상승은 난모세포의 성숙분열이 촉진되고 돼지 난포세포에 있어서도 PI대사가 일어나고 있는 것으로 보고되고 있다. 본 연구에서는 돼지 미성숙 난모세포의 성숙과 단위발생에 미치는 inositol의 영향을 확인하기 위하여 실시하였다. inositol의 농도가 난포란의 성숙에 미치는 영향을 검토하기 위하여 난포란을 각각 $150 \mu mole$, $250 \mu mole$, $350 \mu mole$, inositol을 포함하는 Whitten's 배양액에서 44시간 성숙시킨 결과 $93.57 \pm 4.21, 93.91 \pm 2.71, 92.96 \pm 3.58%$가 성숙되어 대조구의 $87.10 \pm 4.21$보다 유의적(P<0.05)으로 차이를 나타내었다. 난포란의 등급에 따른 inositol의 영향을 확인하기 위하여 형태적으로 난구세포가 치밀한 난포란과 난구세포가 치밀하지 않은 난포란을 $250 \mu mole$ inositol을 포함하는 Whitten's 배양액에서 성숙을 유도한 결과 난구세포가 치밀한 난포란과 난구세포가 치밀하지 않은 난포란에서 inositol을 첨가하였을 때 성숙율은 각각 $95.35 \pm 2.22와 63.55 \pm 8.12$로 inositol을 첨가하지 않은 대조구보다($89.21 \pm 3.69와 48.56 \pm 8.99$) 유의적인 차이를 보였다. 난구세포가 inositol에 의한 성숙에 미치는 영향을 확인하기 위하여 난구세포를 제거한 난포란을 inositol을 포함하는 배지에서 성숙을 유도한 결과 inositol을 첨가하지 않은 처리구보다 양호한 성숙율을 보였다.