• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.118-126
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• 2010

The automated mechanical transmission(AMT) is composed of electronic control management(ECM) and automatic shift gear(ASG). The AMT has advantages which are high efficiency of manual transmissions(MT) and offer operation convenience similar to automatic transmissions(AT). However, it has defects that are the torque gap during gear shift transients and shift time is long. To reduce such defects, it is necessary practically to evaluate error and characteristics as developing simulation model before the control algorithm is applied. In this paper, models are composed of vehicle model and AMT shift control model. Particularly AMT shift control model consists of main clutch management model (MCM) and shift control management model(SCM). The developed models were verified by comparing the simulated and experimental results under the same operational conditions. It can also be used to evaluate shift algorithm.

• Journal of the military operations research society of Korea
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• v.34 no.1
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• pp.79-98
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• 2008

The purpose of this paper is to find the desirable R&D policies in defense area by analyzing causality between GDP and R&D investments in government, private, defense sectors. We have five variables which are composed of GDP, total R&D investment, R&D investments in government, private and defense sectors to figure out the causality between R&D investment in defense sector and other components. In the course of analysis on causality, we took the unit root test of variables to prevent spurious regression. Also we need to take cointegration test about non-stationary variables before the causality test. According to these test results, we took the causality test using ECM(Error Correction Model) for the models which have cointegrating relations. And we took ordinary Granger causality test for model which doesn't have a long-run stationary relationship. As a result of the causality test, it was shown that there exists the long-nu causality to GDP and R&D investments in government and private sectors from other variables. However, there doesn't exist the causality to defense R&D investment from other variables. We found that there doesn't exist the causality between R&D investments in defense and private sectors, and that they are independent.

• Molecules and Cells
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• v.42 no.3
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• pp.218-227
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• 2019

This study was designed to determine the effects of the long non-coding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) on vascular smooth muscle cell (VSMC) apoptosis and extracellular matrix (ECM) disruption in a murine abdominal aortic aneurysm (AAA) model. After injection of PVT1-silencing lentiviruses, AAA was induced in Apolipoprotein E-deficient ($ApoE^{-/-}$) male mice by angiotensin II (Ang II) infusion for four weeks. After Ang II infusion, mouse serum levels of pro-inflammatory cytokines were analysed, and aortic tissues were isolated for histological, RNA, and protein analysis. Our results also showed that PVT1 expression was significantly upregulated in abdominal aortic tissues from AAA patients compared with that in controls. Additionally, Ang II treatment significantly increased PVT1 expression, both in cultured mouse VSMCs and in AAA murine abdominal aortic tissues. Of note, the effects of Ang II in facilitating cell apoptosis, increasing matrix metalloproteinase (MMP)-2 and MMP-9, reducing tissue inhibitor of MMP (TIMP)-1, and promoting switching from the contractile to synthetic phenotype in cultured VSMCs were enhanced by overexpression of PVT1 but attenuated by knockdown of PVT1. Furthermore, knockdown of PVT1 reversed Ang II-induced AAA-associated alterations in mice, as evidenced by attenuation of aortic diameter dilation, marked adventitial thickening, loss of elastin in the aorta, enhanced aortic cell apoptosis, elevated MMP-2 and MMP-9, reduced TIMP-1, and increased pro-inflammatory cytokines. In conclusion, our findings demonstrate that knockdown of lncRNA PVT1 suppresses VSMC apoptosis, ECM disruption, and serum pro-inflammatory cytokines in a murine Ang II-induced AAA model.

• Environmental and Resource Economics Review
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• v.24 no.2
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• pp.311-342
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• 2015

We evaluate two main rationales of massive policy intervention of Lee Administration in the Korean transportation fuel market: high market share of domestic refineries, perceived by the Administration as the result of high market concentration, and asymmetry in price adjustment, perceived as the result of collusion. Domestic refineries, huge in capacity and located at seaports, maintain international competitiveness in price. Considering market openness offering preferential treatment to importers, they set domestic prices competitively on the basis of MOPS prices. Yet, the price competitiveness of domestic refineries is so high that they are able to sustain high market share. We confirm that the Korean before-tax consumer prices of gasoline and diesel are lower than Japan's and the weighted averages of 27 EU countries by as much as 159KRW and 21KRW per liter in the case of gasoline and 170KRW and 63KRW in the case of diesel. Price asymmetry is caused by diverse economic and managerial reasons and, as FTC (2005) states, price asymmetry does not immediately imply exercise of market power or collusion. We analyzed price asymmetry in Korea, Japan and 14 EU countries, and found asymmetry in Korea and 11 EU countries in the case of gasoline and in Korea and 8 EU countries in the case of diesel.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.2
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• pp.133-141
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• 2017

The hybrid acoustic sensor for implantable hearing aid has the structure in which a sound pressure based acoustic sensor (ECM) and a vibration based acceleration sensor are combined. This sensor combines the low frequency sensitivity of an acoustic sensor with the high frequency sensitivity of an acceleration sensor, allowing the acquisition of a wide range of sound from low to high frequency. In this paper, an acceleration sensor for use in a hybrid acoustic sensor has been proposed. The acceleration sensor captures the vibration of the tympanic membrane generated by the acoustic signal. The size of the proposed acceleration sensor was determined to diameter of 3.2 mm considering the anatomical structure of the tympanic membrane and the standard of ECM. In order to make the hybrid acoustic sensor have high sensitivity and wide bandwidth characteristics, the aim of the resonance frequency of the acceleration sensor is to be generated at about 3.5 kHz. The membrane of the acceleration sensor derives geometric structure through mathematical model and finite element analysis. Based on the analysis results, the membrane was implemented through a chemical etching process. In order to verify the frequency characteristics of the implemented membrane, vibration measurement experiment using external force was performed. The experiment results showed mechanical resonance of the membrane occurred at 3.4 kHz. Therefore, it is considered that the proposed acceleration sensor can be utilized for a hybrid acoustic sensor.

• Journal of Information Technology Services
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• v.10 no.2
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• pp.95-117
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• 2011

Today, IT governance has also become a subject of attention along with recent technologies such as ITSM (IT Service Management), PPM (Project Portfolio Management) and Compliance. At the national level, the market is fairly recent. and therefore, lacks detailed research in the field. Models specifically related to EIM has not yet been presented to this day, hence, firms that are considering EIM as a potential part of their information management system may fall into a state of disorder in the process of its implementation. To this end, this research attempts to construct an IT governance model for EIM based on existing models, surveys and interviews. In particular, E-discovery has been applied as means of protecting information assets and its use as evidence. In addition, by applying the research model to a particular global firm and then assessing its documentation management system, the overall feasibility of the research model has been tested.

• Journal of Information Technology Applications and Management
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• v.26 no.5
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• pp.1-12
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• 2019

This study conducted an empirical study on factors affecting the continuous use of mobile payment for users. Based on Technology Acceptance Model (TAM) and Extended Expectation-Confirmation Model of lS Continuance (ECM-ISC), we set up the model and hypothesis by adding habit and utilization range as independent variables. We received 426 valid questionnaires from users who have used continuously mobile payments such as Alipay and Wechatpay in China. The collected data was analyzed by SPSS for validity, reliability, factor analysis, T-test and regression analysis. The result shows that perceived usefulness, perceived risk, habits and utilization range have positive effects on users who use AliPay. Users who use Wechatpay have been affected by perceived usefulness, perceived use of ease, habit and application scope. However, the social influence does not affect both.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.676-686
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• 2016

This study analyzed the long term relationship between the K-REITs' lending rate and interest rate variables based on ARDL (autoregressive distributed lag) and also examined the short term relationship based on the ARDL-ECM model. In the results of the empirical test, there is a co-integration relationship among the K-REITs' lending rate, 3 year government bond (rate), 3 year government bond (rate), corporation bond (rate) (AA-, 3year) and general fund loan rate. This means that the K-REITs' lending rate is related to the long term interest rate. The corporate general fund loan rate has a significant correlation with the K-REITs' lending rate in the long term relation and short term adjustment process. The establishment of a management plan by the REITs considering the trends in the corporate general fund loan rate in the decision making process for finance sector borrowings can be practically helpful for the K-REITs.

• Information Systems Review
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• v.17 no.1
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• pp.171-197
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• 2015

SNS provider's biggest interest lies in enhancing user satisfaction through user request analysis and developing services to induce continuous use of those devices. In particular, setting up management directions to develop SNS at maturity is important and it is also important to identify the functions which SNS users are pursuing for and identify what's considered unsatisfiable among the services currently provided in light of user expectations. To this end, this study further presents sociality quality and personal emotional quality reflecting the characteristics of SNS to the existing quality factors and expands to Expected Confirmation Model. This study further took into account of sociality quality and personal emotional quality reflecting the characteristics of SNS and approached to them from the perspective of quality in a comprehensive way, analyzed the degree of impact on recognition factors, and presented the factors that had an impact on the satisfaction with usage and intention to use continuously.

• Biomedical Science Letters
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• v.27 no.3
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• pp.142-153
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• 2021

Liver fibrosis is a wound-healing response to chronic liver injury, which is caused by the continuous and excess deposition of extracellular matrix (ECM). The aim of this study is to investigate whether Uncaria rhynchophylla water extract (UR) can ameliorate thioacetamide (TAA)-induced liver fibrosis. The liver fibrosis model was induced on C57BL/6 mice by intraperitoneal injection with TAA three times a week for 8 weeks. UR (200 mg/kg) or silymarin (50 mg/kg) was administered orally daily for 8 weeks. Biochemical analyses including AST, ALT, MPO, and Ammonia levels were measured in serum. In the mice liver tissues, western blot and histological staining were analyzed. As a result, UR dramatically reduced the levels in serum AST, ALT, MPO, and Ammonia levels. UR treatment regulated NADPH oxidase factors expression, and antioxidant enzymes except for GPx-1/2 were significantly increased via Nrf2 activation. Furthermore, pro-inflammatory mediators, such as COX-2 and iNOS were markedly suppressed through the inhibition of NF-κB activation. Expressions of ECM-related protein including α-SMA and Collagen I were noticeably decreased. The additional histological evaluation confirmed that hepatocyte damage and collagenous fiber accumulation were attenuated. Taken together, these data suggest that UR possessed hepatoprotective effects in TAA-induced liver fibrosis via the NF-κB inactivation and Nrf2 activation. Therefore, UR may act as a potential therapeutic drug against liver fibrosis.