• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.131-136
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• 1994

In the present study, in order to make an in vitro model of gastric mucosa for physiological and pharmacological studies, we established two immortalized gastric surface mucous cell lines (GSM06 and GSM10), which produce periodic acid-Schiff (PAS)-and concanavalin A (Con A)-positive glycoproteins, from a primary culture of gastric fundic mucosal cells of adult transgenic mice harboring a temperature-sensitive simian virus 40 large T-antigen gene 〔1]. Gastric fundic mucosal cells were isolated as a modification of a previously described method for rats by Schepp et al. (2). The isolated gastric fundic mucosal cells were cultured in DME/F12 medium supplemented with 2% fetal bovine serum (FBS), 1% ITES (consisting of 2 mg/1 insulin, 2 mgg/1 transferrin, 0.122 mg/1 ethanolamine and 0.00914 mg/1 sodium selenite) and 10 ng/ml recombinant epidermal growth factor (EGF) in a collagen-coated culture dish. To remove fibroblastic cells from the culture, gastric mucosal cells were incubated in the culture medium containing dispase (25 U/ml) for 24 h. The cells, uncontaminated with fibroblastic cells, were then cloned by colony formation. In our series of three attempts, two cell lines (GSM06 and GSM10) have been established at last. The cells proliferated, attached to the dish ana grew until confluent monolayers were formed, and maintained tight contact with neighboring cells. Both GSM06 and GSM10 cells have now been in culture for more than 9 months with regular passaging. The either cell produced

• Journal of Ocean Engineering and Technology
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• v.25 no.3
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• pp.66-72
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• 2011

This is the fourth of a series of companion papers dealing with the mechanical property reductions of various marine structural steels. Even though a reduction of the elastic modulus according to temperature increases has not been obtained from experiments, high temperature experiments from room temperature to $900^{\circ}C$ revealed that initial the yield strength and tensile strength are both seriously degraded. The mechanical properties obtained from high temperature experiments are compared with those from EC3 (Eurocode 3). It is found that the high temperature test results generally comply with the prediction values by EC3. Based on the prediction of EC3, time domain nonlinear finite element analyses were carried out for a blast wall installed on a real FPSO. After applying the reduced mechanical properties, corresponding to $600^{\circ}C$ to the FE model of the blast wall, more than three times the deflections were observed and it was observed that most structural parts experience plastic deformations exceeding the reduced yield strength at the high temperature. It is noted that a protection facility such as PFP (passive fire protection) should be required for structures likely to be directly exposed to fire and explosion accident.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.674-680
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• 2013

This paper investigates the impact of liquidity constraints on investment expenditures of family and non-family firms. We analyze the ownership structure of family firms to determine whether family control alleviates or exacerbates investment-cash flow sensitivity in domestic firms. To examine the impact of liquidity constraints on investment expenditures of family and non-family firms, we used a financial data of 644 Korea Exchange traded companies over the 2000 - 2010 period. We estimated a time-series and cross-sectional regression model, using samples of family firms and non-family firms. The results show that cash flow is not associated with investment expenditure in family firms, whereas cash flow has a positive impact on investment in non-family firms. Our results show that lower or no investment-cash flow sensitivities in family-controlled firms are mainly attributable to lower agency costs through strong monitoring activities of family members. Higher investment-cash flow sensitivities are observed in non-family firms with more agency problems. This suggests that investment-cash flow sensitivities would be useful measures of liquidity constraints.

• Journal of Navigation and Port Research
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• v.44 no.5
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• pp.382-391
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• 2020

In line with the trend of global transport volume which has increased rapidly over the years, internal transportation in seaports is always conducted with high frequency. Thus, there is always much potential for traffic jams as well as high transportation costs and emissions. Many efforts have been initiated to streamline the inter-terminal container transport (ITT) through the development of automated vehicles and equipment as well as using private transport facilities to overcome these limitations. The purpose of this paper to develop a framework to design, analyze, and validate the efficiency of a new ITT system in a port area based on the monorail network and automatic vehicles. First, the number of shuttles and loaders was determined depending on the transport demand scenario. Next, a simulation model was applied to evaluate the system performance as well as gain more insight into the working process of the ITT system. Finally, by setting goals for the performance indicators, the results showed that the system was highly efficient with 100% of the containers delivered to their destination on time. Besides, a series of other performance tracking was provided to provide insight into the system's capabilities.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.31-42
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• 1989

An experimental and theoretical investigation was conducted in the present study to explore the mechanical behavior of concrete under dynamic loads. The stress-strain behavior and mechanical characteristics of concrete under various strain-rates were studied from several series of experiments. A new constitutive theory was derived on the basis of viscoplasticity to model the dynamic behavior of concrete. The theory is verified by the present test results as well as other previous test data. It is found from the present study that the strength of concrete is greatly increased with the increase of strain rate and that the rate of strength increase is greater in tension than in compression. The present theory as well as present test results will provide very useful basis to explore the dynamic behavior of concrete structures.

• Journal of Korean Society of Steel Construction
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• v.25 no.3
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• pp.223-231
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• 2013

Recently, high-performance steels have been increasingly used for structural materials in buildings and bridges with the demand for high-rise and long-span of main structures. This paper offers a series of basic study for the design specification of structural members using high performance steel, that is material properties of HSA800 (High-performance rolled steel for building structures). Built-up square tube stub columns with variables of width-to-thickness ratios are planned as a parametric study in order to investigate the local buckling behaviors and check the current design limit of width-to-thickness ratio. In addition, the buckling behaviors of stub columns obtained finite element (FE) analysis were compared with those from experimental tests. The verified FE model was used for parametric study and checked applicability of high-strength steel on current design specification.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.7
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• pp.149-158
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• 2012

Much attention is being paid to social media because of their potentials to draw collective intelligence. In this context does this study attempt to draw some implications of social media as knowledge creation platform and suggest a conceptual framework of social media management. Information sharing among the public through social media literally produces profound influence throughout the society and thus not only business firms but all levels of public institutions, including government are seeking to take its advantage for various purposes such as public relations, crowd sourcing, etc. Especially considering that social media open the possibility of social knowledge creation platform in the Big Data era, this study is perhaps able to contribute to further development of social media management model together with a series of measuring indexes.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.5
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• pp.67-77
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• 2007

The images of MODerate resolution Imaging Spectroradiometer (MODIS) that provide wider swath and shorter revisit frequency than Land Satellite (Landsat) and Satellite Pour I' Observation de la Terre (SPOT) has been used fer land cover classification with better spatial resolution than National Oceanic and Atmosphere Administration/Advanced Very High Resolution Radiometer (NOAA/AVHRR)'s images. Due to the advantages of MODIS, several researches have conducted, however the results for the land cover classification using MODIS images have less accuracy of classification in small areas because of low spatial resolution. In this study, uncertainty of paddy fields classification using MODIS images was conducted in the region of Gyeonggi-do and the relation between this uncertainty of estimating paddy fields and topographical factors was also explained. The accuracy of classified paddy fields was compared with the land cover map of Environmental Geographic Information System (EGIS) in 2001 classified using Landsat images. Uncertainty of paddy fields classification was analyzed about the elevation and slope from the 30m resolution Digital Elevation Model (DEM) provided in EGIS. As a result of paddy classification, user's accuracy was about 41.5% and producer's accuracy was 57.6%. About 59% extracted paddy fields represented over 50 uncertainty in one hundred scale and about 18% extracted paddy fields showed 100 uncertainty. It is considered that several land covers mixed in a MODIS pixel influenced on extracted results and most classified paddy fields were distributed through elevation I, II and slope A region.

• Journal of Energy Engineering
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• v.2 no.3
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• pp.268-275
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• 1993

A series of parametric investigations are performed in order to resolve the flow characteristic of a Quebec city stoker incinerator. The parameters considered in this study are five internal configurations of the Quebec city stoker itself and its modified ones, primary air velocity, the injection velocity and angle of the secondary air, and the reduction of the stoker exit area. A control-volume based finite-difference method by Patankar together with the power-law scheme is employed for discretization. The resolution of the pressure-velocity coupling is made by the use of SIMPLEC algorithm. The standard, two equation, k-$\varepsilon$ model is incorporated for the closure of turbulence. The size of recirculation region, turbulent viscosity, the mass fraction of the secondary air and pressure drop are calculated in order to analyze the characteristics of flow field. The results are physically acceptable and discussed in detail. The flow field of the Quebec city stoker shows the strong recirculation zone together with the high turbulence intensity over the upper part of the incinerator.

• Science of Emotion and Sensibility
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• v.12 no.4
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• pp.403-410
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• 2009

The purpose of this study was to find whether there is sound quality difference among mobile service providers in terms of ringtone in mobile phones, and identify factors that contribute to the difference of sound quality. A series of experiments were performed to identify the source of sound difference while controlling brand factor of the leading company. Mobile service provider, phone manufacturer, phone model variation, specific music genre and contents provider factors were examined. The results showed there was sound quality difference among mobile service providers. The difference comes from mobile phones provided to service provider and sound contents. There was difference in sound quality among same models that provided to different service providers. The different sound making process contributed to the difference of sound quality. The genre effect was not clear. To complement the limitation of samples used, an interview with the sound expert of mobile device was performed. The results showed hardware parts used and careful tuning of the device can influence to the sound quality of the mobile phone.