• Journal of Korean Society for Atmospheric Environment
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• v.31 no.2
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• pp.164-172
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• 2015

Seoul subway plays an important part for the public transportation service in Seoul metropolitan area. As the subway system is typically a closed environment, frequent air pollution problems occurred and passengers get malhealth impact. Especially particulate matters (PM) is well known as one of the major pollutants in subway environments. The purpose of this study was to compare the concentrations of $PM_{10}$ and $PM_{2.5}$ in the Seoul subway system and to provide fundamental data in order to management of subway system. $PM_{10}$ and $PM_{2.5}$ samples were collected in the M station platform and tunnel of Subway Line 4 in Seoul metropolitan and in an outdoor location close to it from Apr. 21, 2010~Oct. 27, 2013. The samples collected on teflon filters using $PM_{10}$ and $PM_{2.5}$ mini-volume portable samplers and PM sequential sampler. The PM contributions were $48.6{\mu}g/m^3$ (outdoor), $84.6{\mu}g/m^3$ (platform) and $204.8{\mu}g/m^3$ (tunnel) for $PM_{10}$, and $34.6{\mu}g/m^3$ (outdoor), $49.7{\mu}g/m^3$ (platform) and $83.1{\mu}g/m^3$ (tunnel) for $PM_{2.5}$. The $PM_{10}$ levels inside stations and outdoors are poorly correlated, indicating that $PM_{10}$ levels in the metro system are mainly influenced by internal sources. In this study, we compared PM concentrations before and after operation of ventilation and Electrostatic Precipitator (EP). Despite the increased PM concentration at outdoor, $PM_{10}$ concentration at platform and tunnel showed the 31.2% and 32.3% reduction efficiency after operation the reduction system. The overall results of this study suggest that the installation and operation of the ventilating system and EP should have served as one of the important components for maintaining the air quality in the subway system.

• The Journal of the Acoustical Society of Korea
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• v.34 no.6
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• pp.411-422
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• 2015

This paper presents an overview of the geological environment investigation and underwater acoustic measurements for the purpose of "Study on the Relationship between the Geological Environment and Acoustic Propagation in Shallow Water", which are jointly carried out by KIOST (Korea Institute of Ocean Science & Technology) and Hanyang University in the western shallow water off the Taean peninsula in the Yellow Sea in April-May 2013. The experimental site was made up of various sediment types and bedforms due to the strong tidal currents and coastal geomorphological characteristics. The geological characteristics of the study area were intensively investigated using multi-beam echo sounder, sub-bottom profiler, sparker system and grab sampler. Acoustic measurements with a wide range of research topics in a frequency range of 20~16,000 Hz: 1) low frequency sound propagation, 2) mid-frequency bottom loss, 3) spatial coherence analysis of ambient noise, and 4) mid- frequency bottom backscattering were performed using low- and mid-frequency sound sources and vertical line array. This paper summarizes the topics that motivated the experiment, methodologies of the acoustic measurements, and acoustic data analysis based on the measured geological characteristics, and describes summary results of the geological, meteorological, and oceanographic conditions found during the experiments.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.108-113
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• 2006

Urban conditions, such as existing underground facilities and ambient noise due to cultural activity, restrict the general application of conventional geophysical techniques. At a tunnelling site in an urban area along an existing railroad, we used the refraction microtremor (REMI) technique (Louie, 2001) as an alternative way to get geotechnical information. The REMI method uses ambient noise recorded by standard refraction equipment and a linear geophone array to derive a shear-wave velocity profile. In the inversion procedure, the Rayleigh wave dispersion curve is picked from a wavefield transformation, and iteratively modelled to get the S-wave velocity structure. The REMI survey was carried out along the line of the planned railway tunnel. At this site vibrations from trains and cars provided strong seismic sources that allowed REMI to be very effective. The objective of the survey was to evaluate the rock mass rating (RMR), using shear-wave velocity information from REMI. First, the relation between uniaxial compressive strength, which is a component of the RMR, and shear-wave velocity from laboratory tests was studied to learn whether shear-wave velocity and RMR are closely related. Then Suspension PS (SPS) logging was performed in selected boreholes along the profile, in order to draw out the quantitative relation between the shear-wave velocity from SPS logging and the RMR determined from inspection of core from the same boreholes. In these tests, shear-wave velocity showed fairly good correlation with RMR. A good relation between shear-wave velocity from REMI and RMR could be obtained, so it is possible to estimate the RMR of the entire profile for use in design of the underground tunnel.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.973-979
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• 2016

Lentils (Lens culinaris) have been gaining increasing attention recently as a top five superfood, as they are high in protein and other essential nutrients, including folate, iron, potassium, and various antioxidants. In the present study, phenolic extracts from four different lentil cultivars (green, red, French, and beluga) were evaluated for their total phenolic contents and in vitro antioxidant activities. Total polyphenol and flavonoid contents of four different lentil extracts were 27.30~30.30 mg tannic acid equivalents (TAE)/g and 13.14~16.29 mg quercetin equivalents (QUE)/g, respectively. Beluga and red lentil extracts showed higher polyphenol contents than others (P<0.05), whereas there was no significant difference in flavonoid contents among the four lentil cultivars. $RC_{50}$ values of the lentil extracts for DPPH radical, ABTS radical, and $H_2O_2$ were $57.42{\sim}64.49{\mu}g/mL$, $66.11{\sim}75.69{\mu}g/mL$, and $59.72{\sim}72.86{\mu}g/mL$, respectively. Among the four lentil extracts, beluga lentil extract showed the most potent scavenging effect in all three reactive oxygen species (ROS) scavenging assays, and thus beluga extract was further tested for its inhibitory effect on early peroxidation of linoleic acid. The results showed that beluga lentil extract significantly inhibited linoleic acid peroxidation in a dose-dependent manner (concentration required for 50% reduction=$222.76{\m}g/mL$). In addition, beluga lentil extract showed a significant protective effect against alcohol-induced cytotoxicity in AML-12 cells (normal mouse hepatocyte cell line). Taken together, these results suggest that lentil extracts represent potential sources of natural antioxidants, and further studies will be necessary to determine their protective effects against oxidative stress in vivo.

• Journal of Korean Academy of Nursing
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• v.20 no.3
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• pp.281-299
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• 1990

The organization of nursing department Significantly effects the hospital management. Especially, The head nurse is one of the most important position because head nurse is a first-line manager in the hospital level, a middle manager in nursing service organizations level and the top manager in each nursing unit level. This study was attempted to show the ideal model and nile by compare head nurses' role perception with staff nurses' role expectation according to two types of hospital. The survey was conducted among 94 head nurses and 233 staff nurses who are working at 5 different University Hospitals over 600 beds and 93 head nurses and 218 staff nurses Who are working at 12 different General Hospitals between 100∼300 beds in Seoul. The data was collected in a period from 8th September to 13th October in 1989 and the instrument used for this study was based on Han's one and reffered back to many literary sources and revised. The collected data was analysed by computer using S.P.S.S. program as a Mean, Percentage, Cronbach's alpha, Chi-Square, t-test and ANOVA. 1. The study was compared to the difference of the two subject group's general characteristics according to a type of hospital. As a relult, there were significant differences in age, educational background and career. 2. This Study was compared to the difference of the two subject group's role perception and role expection about each question according to a type of hospital. The result of this comparisons as follows : First, These were the most important issue between both groups : “Head nurse has to know about her staff's events and problems and then help them to solve that promptly.” Second, These were the least important issue between both groups : “Head nurse has an interview with patient's family and visitors”, “Head nurse is interested in her staff's privacy.” 3. This study was compared to the differences of each role areas according to a type of hospital. As a result, there were no significant differences both two subject groups except nursing manager role in staff nurses' group(t＝-2.893, df＝449.0, p＝0.004). 4. This study was tested to the difference of the two subject groups according to general characteristics. As a result, All of that there were no significant differences.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.315-320
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• 2014

Recently, although the requirement of quality of VOD content has been transferred upto the class of HD, conventional management systems characterized by OS dependency are truly limited in quality of video image, stability, and compatibility of network environments. In addition most of the content management systems realize very limited capabilities for the real affairs of content management and distribution services in such an OS dependent environment. In this paper, we propose a new scheme of HD-Class VOD Content Management System to solve these problems. We design and implement the proposed system based on open sources by using H.264 video compression method. The proposed system offers high quality content management method based on opened systems and independent on-line distribution method so that it can be realized as an integrated management scheme for VOD contents. Moreover, our system solves the problems of occasional cutting-down video, small screen, and poor image quality that exist in the conventional wmv-type CMS. According to the result of performance evaluation, our system maintains sufficient performance and tolerence for the case of large scale HD content operations or fabrications. We expect that the proposed integrated DB scheme will especially be effective when the content management applications are changed from Internet Web environments to mobile terminal environments.

• Korean Journal of Optics and Photonics
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• v.15 no.4
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• pp.385-390
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• 2004

In this paper, we designed a 4-bit optical true time-delay(TTD) for phased array antennas(PAAs), which is composed of a wavelength-fixed optical source, 2 ${\times}$ 2 optical MEMS switches, and fiber-optic delay lines. A 4-bit TTD with a unit time delay difference of 6 ps for 10-GHz PAAs has been implemented. Measurement results on time delay show an error of -0.4 ps at maximum, corresponding to a radiation angle error of less than 1.63$^{\circ}$. Thus, the TTD implemented in this research performs in excellent agreement with theory. Each TTD line, composed of MEMS switches and fiber-optic delay lines, connected to the corresponding antenna element has insertion loss in between 1.36 ㏈ and 2.40 ㏈ depending upon the setup of the switches. On the other hand, the insertion loss difference between TTD lines was 0.32 ㏈ at maximum for a fixed radiation angle. The TTD structure proposed in this paper might be more reliable and economical than those previously proposed using tunable wavelength sources if proper power equalization either with gain control of RF amplifiers or variable attenuators is achieved.

• Korean Journal of Environmental Biology
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• v.34 no.2
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• pp.116-123
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• 2016

The ecotoxicity tests for metal plating wastewater were conducted using Daphnia magna (D. magna) and Euglena agilis (E. agilis). Evaluation for sources of toxicity was performed by 1) Correlation analysis between the concentration of individual metals in the metal plating wastewater and the toxic effects on D. magna, 2) Toxicant identification evaluation methods including graduated pH method, EDTA procedure and sodium thiosulfate procedure, 3) Comparison of toxic effect value ($EC_{50}$ or $LC_{50}$) of individual metal on D. magna and it's concentration in the metal plating wastewater. To evaluate the possibility of E. agilis, a Korean domestic organism, as a test model organism for metal plating waste water, E. agilis toxicity test was also assessed using on-line euglena ecotoxicity system (E-Tox system). Based on toxicant characterization test using D. magna, it was expected that SS, oxidants and heavy metals are responsible for toxicity of metal plating waste water. Especially Cu, Hg, and Ag were the major cationic metals that caused toxicity. E. agilis is less sensitive than D. magna based on the $EC_{50}$ value however it shows prompt response to toxic test substances. E. agilis shows even a significant effect on the cell swimming velocity within 2 min to toxic metal plating wastewater. Our study demonstrates that E. agilis test can be a putative ecotoxicity test for assessing the quality of metal plating waste water.

• Korean Journal of Plant Tissue Culture
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• v.24 no.4
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• pp.239-256
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• 1997

Plants belonging to the category of 2n apomixis or agamospermy form embryos and seeds without the processes of normal meiosis and syngamy. Seeds produced in this way have identical genotype of their maternal parent. Three different types of agamospermy are recognized: diplospory, apospory, and adventitious (adventive) embryony. $F_1$ hybrid cultivars cannot be used as seed sources in the next ($F_2$) generation because this generation would be extremely variable as a result of genetic segregation. Hybrid vigor is also reduced in the $F_2$ generation. Therefore, parental stocks for hybrid seed production need to be maintained and cross must be continuously repeated. Agamospermic 2n apomixis would make it possible to fix the genotype of a superior variety so that clonal seeds faithfully representing that genotype could be continuously and cheaply produced independent of pollination. That is, $F_1$ hybrid seeds could be produced for many generations without loss of vigor or genotype alteration. Production of apomictic $F_1$ hybrid seed would be simplified because line isolation would not be necessary to produce seed or to maintain parental lines, and the use of male-sterile lines could be avoided. Overall, apomixis would enable a significant reduction in hybrid seed production costs. Additionally, the production of clonal seed is not only important for seed propagated crops, but also for the propagation of heterozygous fruit trees and timbers. Clonal seed would help avoid costly and time-consuming vegetative propagating methods that are currently used to ensure the large-scale production of these plants. Apomixis is scattered throughout the plant kingdom, but few important agricultural crops possess this trait Therefore, most research to date has centered on introgressing the trait of apomixis into agricultural crops such as wheat, maize, and some forage grasses from wild distant relatives by traditional cross breeding. The classical breeding approach, however is slow and often impeded by many breeding barriers. These problems could be surmounted by taking mutagenesis or molecular approach. Arabidopsis thaliana is a tiny sexually reproducing plant and is convenient in constructing and screening in molecular researches. Male-sterile mutants of Arabidopsis are particularly suitable genetic background for mutagenesis and screening for apomictic mutants. Molecular approaches towards isolating the genes controlling the apomictic process are feasible. Direct isolation of genes conferring apomixis development would greatly facilitate the transfer of this trait to wide variety of crops. Such studies are now in progress.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.8
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• pp.1149-1156
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• 2001

Previous studies conducted with swine have reported that the mobile nylon bag technique (MNBT) does not always accurately predict in vivo nutrient digestibilities. Therefore, in this study, the MNBT was modified so that nutrient digestibilities would more closely resemble those from conventional (Con) digestibility studies obtained using the indicator method. A total of 19 feeds were tested including five cereal grains, five legumes, three high protein sources and six mixed diets. The principle changes to the MNBT included the use of a fecal collection harness which minimized the number of bags lost. In addition, previous protocols involved pooling of bags within pig while in the present experiment all bags were analyzed separately to increase the precision of the test. Finally, chemical analyses were done using the entire nylon bag plus residue rather than opening.the bags and scraping out the contents. With the exception of the barley sample (p=0.01), dry matter digestibility (DMD) coefficients obtained with the MNBT were not significantly different from those obtained with the indicator method. The linear regression equation relating the MNBT to the indicator method was Con DMD=-O.77+1.02 MNBT DMD ($r^2=0.93$: p<0.0001). There was no significant (p>0.05) difference in gross energy digestibility (GED) coefficients determined using the MNBT or the indicator method for any of the 19 feeds. The regression line equation relating the MNBT to the indicator method was Con GED=-5.68+1.06 MNBT GED ($r^2=0.94$: p<0.0001). The MNBT was less effective in predicting in vivo crude protein digestibility (CPD) than it was in predicting dry matter and energy digestibility. Differences greater than five percentage units were observed for two of the legumes, Kabuli chickpeas (p=0.02) and the extruded pea-canola seed mixture (p=0.01) as well as for three of the mixed diets including the unheated hulled barley-based diet (p=0.01), the unheated hulless-barley based diet (p=0.08) and the barley-soybean meal based diet (p=0.008). The regression equation relating the MNBT to the indicator method was Con CPD=5.75 + 0.90 MNBT CPO ($r^2=0.76$; p<0.0001). This study indicates that the modified MNBT can be used for the rapid determination of dry matter and energy digestibility in a wide variety of ingredients. For the measurement of crude protein digestibility, the technique produces results similar to conventional digestibility studies for cereal grains and high protein feeds but tends to overestimate protein digestibility for legumes and mixed diets.