• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.11
• /
• pp.1009-1017
• /
• 2010

As rotating machines play an important role in industrial applications such as aeronautical, naval and automotive industries, many researchers have developed various condition monitoring system and fault diagnosis system by applying various techniques such as signal processing and pattern recognition. Recently, fault diagnosis systems using artificial neural network have been proposed. For effective fault diagnosis, this paper used MLP(multi-layer perceptron) network which is widely used in pattern classification. Since using obtained signals without preprocessing as inputs of neural network can decrease performance of fault classification, it is very important to extract significant features of captured signals and to apply suitable features into diagnosis system according to the kinds of obtained signals. Therefore, this paper proposes the decision method of the proper feature vectors about each fault signal for neural-network-based fault diagnosis system. We applied LPC coefficients, maximum magnitudes of each spectral section in FFT and RMS(root mean square) and variance of wavelet coefficients as feature vectors and selected appropriate feature vectors as comparing error ratios of fault diagnosis for sound, vibration and current fault signals. From experiment results, LPC coefficients and maximum magnitudes of each spectral section showed 100 % diagnosis ratios for each fault and the method using wavelet coefficients had noise-robust characteristic.

• Journal of Life Science
• /
• v.19 no.6
• /
• pp.836-838
• /
• 2009

Tissue plasminogen activator (tPA) is very useful for dissolving the clots of blood, however, the use of tPA is limited to only 3-5% of ischemic stroke patients because of the narrow therapeutic time windows and negative side effects. Previous evidences suggest that limitation of tPA in thrombolytic therapy may be related to the upregulation of MMPs. However, little is known about the regulatory mechanism. In this study, we examined the role of tPA on MMP upregulation in rat neuronal cells. tPA (5 ${\mu}g$/ml) increased MMP-9 levels of neuronal cells in a time dependent manner. Hypoxia/reoxygenation amplified tPA-induced MMP-9 levels significantly. Pretreatment with JNK inhibitor SP600125 reduced the MMP-9 response. These results suggest that tPA can upregulate MMPs in neuronal cells and that JNK kinase may be involved.

• Journal of Life Science
• /
• v.24 no.4
• /
• pp.454-460
• /
• 2014

In a previous study, we found that methanolic extracts of immature fruits of Satuma mandarin (Citrus unshiu Marc. var. okitsu) contained relatively high amounts of phytochemicals. Here we show that a combined treatment consisting of immature fruits of Satuma mandarin and cisplatin induced strong apoptotic response in human melanoma A375 cells. We further investigated the mechanisms by which immature fruits of Satuma mandarin augment cisplatin-induced apoptosis in A375 cells. Satuma mandarin up-regulated the expression of nitric oxide synthase (NOS), elevated nitric oxide ($NO^{\cdot}$) production, and weakening the anti-apoptotic signals inhibitor of apoptosis (IAP) family, thus facilitating the process of apoptosis. These results suggest that immature fruits of Satuma mandarin in combination with cisplatin might have therapeutic value in melanoma treatment worthy of further development.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2001.04a
• /
• pp.81-81
• /
• 2001

초지 공정은 wire, roll, pump등의 회전체로 이루어진 공정이 거의 대부분이기 때문에 주기적으로 변동하는 성분들이 많고, QCS(Quality Control System) 및 DCS(Distributed Co n ntrol System)상에 서 의 자동 Control Logic에 의 한 불안정 (Fluctuation)요소도 내 재 되 어 있 어 이에 대한 분석이 필요하다. 이러한 주기적인 변동은 제품의 여러 물성(평량, 두께, 광택 도등) 에 영향을 미치게 되어 품질의 균일성이나 프로파일에 영향을 미치게 된다. 따라서 공정상이나 품질에서 주기적으로 변동하는 성분을 추출하여 공정 각 성분과 연관을 시키변 품질에 나타나는 주기적 성분의 요인이 어느 부분에서 기인하는 지를 직접적으로 찾아낼 수 있고 이의 개선을 통해 품질의 균일성 및 프로파일 향상을 꾀할 수 있다. 본 연구에서는 Air padded type 헤드박스 초지기에서 DAQ(Data Acquisition) System 을 이용하여 각 공정별로 MD(Machine Direction)방향으로의 변동을 측정하고 제품의 물성 변동과 비교하였다. DAQ System은 각 공정상의 전기적 신호를 높은 주파수 영역까지 다채널로 동시에 받 아 들일 수 있는 장치로 이 시스템을 활용하여 공정상의 Machine chest 농도, Stock box 유량 및 레벨, Fan pump RPM, Cleaner압력, Screen압력, H!B압력 및 레벨, Silo level등 공 정요소의 변동상태와 상호영향을 분석하였다. 이러한 공정 각 요소의 변동과 MD 방향의 제품 물성 값(Tapio, Paper Variation Analyzer에 대한 비교 분석결과 제품 평량에서 주기적인 변동성분을 확인할 수 있었고 이중 큰 비 중을 차지하는 것이 fνB 레벨 변동주기와 일치하는 것을 찾아낼 수 있었다. 이에 근거하여 D DCS system의 control 요소인 튜닝 parameter(P,I 값)들을 미 세 조정 하여 제 품의 MD방향 평량 변동 진폭을 기존 수준의 30% 수준으로 감소시킬 수 있었다. 그 결과 COV(표준편차/ 평량)값을 0.8-1.2%에서 0.6-0.8%수준으로 낮출 수 있었고 이에 따라 CD (Cross Direction) 방향의 제품 Profile도 함께 개선되는 효과를 거둘 수 있었다.

• Journal of Internet Computing and Services
• /
• v.19 no.1
• /
• pp.105-111
• /
• 2018

This paper presents the analysis of image quality with FHD(Full HD) resolution camera equipped DIC(Digital Image Correlation) platform for the measurement of the architectural structure's relative displacement. DIC platform was designed based on i.MX6 of Freescale. Displacement measurement based on DIC method, the error is affected by image quality factors as pixel number, brightness, contrast, and SNR[dB](Signal to Noise Ratio). The effect were analyzed. The displacement of ROI(Region Of Interest) area within the image was measured by sub-pixel units based on DIC method. The non-contact telemetry property of DIC method, it can be used to long distance non-contact measurement. The various displacement results was measured and analyzed with the image quality factor adjustment according to the distance(25m, 35m, 50m).

• Development and Reproduction
• /
• v.6 no.1
• /
• pp.1-6
• /
• 2002

To elucidate the mechanism underlying the embryotropic effect of extracellular matrix(ECM) on the preimplantation development of mammalian embryos, the involvement of mitogen-activated protein kinase(MAPK) downstream the integrin signaling was examined in mouse blastocysts. Blastocysts were cultured in the presence of growth factor-reduced(GFR) Matrigel(0.5％, v/v). MAPK activity was measured by in vitro phosphorylation of myelin basic protein by the Erk1/2 antibody immunoprecipitates of embryonic extract following the Matrigei treatment. MAPK activity of the early blastocysts rapidly increased within 10 min fo1lowing the Matrigel treatment. When the embryos were cultured for 12 h in the presence of Matrigel, the MAPK activity was significantly higher than that ot the control embryos. PD098059, a MAPK kinase(MEK) inhibitor, attenuated the effect of Matrigel on the change in MAPK activity. Taken together, it suggested that the embryotropic effect of ECM proteins might be mediated by the activation of MAPK cascade.

• Journal of Broadcast Engineering
• /
• v.13 no.5
• /
• pp.565-573
• /
• 2008

This paper proposes noise reduction methods to improve the channel estimation performance in Equalization On-Channel Repeater (E-OCR) for Terrestrial-Digital Multimedia Broadcasting (T-DMB) system. In the E-OCR for T-DMB system, the channel estimation is performed by the pilot signal extraction and the channel coefficient estimation. Since the performance of the channel estimation highly depends on the estimated channel coefficients whose accuracy is associated with the received signal-to-noise ratio (SNR), it is important to reduce noise existing at the estimated channel coefficients. To reduce such noise components, various noise reduction methods of the estimated channel coefficients based on the M -point weighted moving average are proposed. Computer simulations show that the proposed methods improve the estimation performance by more than 2 to 3 dB in terms of the symbol error rate after equalization.

• Journal of Sensor Science and Technology
• /
• v.11 no.3
• /
• pp.171-182
• /
• 2002

The differential electromagnetic transducer for IME(implantable middle ear) system, which have two small permanent magnets glued with the same pole facing each other in the coil, has high vibration efficiency and does not influenced by external magnetic field. In this paper, using finite element method, highly efficient structure of the transducer was proposed and vibration force of the transducer was calculated by electromagnetic theory. And the necessary vibration force of transducer to transmit the sound signal to inner ear when the transducer is attached at stapes was calculated and the design parameters of the transducer were investigated. Using the parameters, the differential electromagnetic transducer was manufactured in small size to implant in confined human middle ear. And it was examined by unloaded and loaded vibration experiment using temporal bone sampled from cadaver.

• Korean Journal of Food Science and Technology
• /
• v.52 no.3
• /
• pp.249-254
• /
• 2020

Argyreia capitata (Vahl) Choisy is a species of the genus Argyreia. Although many studies have analyzed the biological activity of A. nervosa, A. speciasa, and A. acuta, the anti-inflammatory effect of A. capitata extract (ACE) remains unclear. In this study, we evaluated the anti-inflammatory effect of ACE using lipopolysaccharide (LPS)-induced inflammatory markers in RAW 264.7 cells. We confirmed that the ACE inhibited the LPS-induced NO (nitric oxide) and iNOS (inducible nitric oxide synthase) expression in RAW 264.7 cells. ACE suppressed not only the LPS-induced phosphorylation of IKK, IκB, and p65 but also IL-1β expression. Collectively, these results suggest that ACE is a novel anti-inflammatory agent that suppresses iNOS expression, NO production, and the NF-κB signaling pathways.

• Journal of Internet Computing and Services
• /
• v.9 no.1
• /
• pp.43-54
• /
• 2008

In this paper, we implement an automatic entity information management system for smart refrigerator using RFID technology in which objects containing electronic tags are automatically identified using radio wave. Unlike current "smart" refrigerators, the system presented in this paper implements smart tag information acquisition mechanism and real-time information management system to provide various information on entities in refrigerators to local and remote users. As the first step, this paper analyzes the requirements for smart refrigerator system based on the RFID and suggests design considerations. Based on the analysis, we propose and implement an efficient tag location tracking method based on antenna transfer method and an intelligent tag information management system based on embedded database and web server. We also provide a wide range of experimental results on the number of tags identified at a time and the tag recognition ratio according to the RFID antenna transfer speed and the angle between tag reader and tags.