• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.83-90
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• 1997

Aiming at the treatment of large volumes of gas with a low concentration of poorly water soluble VOC(Volatile Organic Compound), a new system is proposed: the combination absorption tower/bioreactor. In the scrubber part of the bioscrubbing system, the contaminating compounds are absorbed in a aqueous phase. The contaminated scrubbing liquid is transported to the bioreactor, where the compounds are biodegraded by aerobic microorganisms (mainly to carbon dioxide, water, and biomass). In this study, separation of a volatile organic compound(VOC) out of a waste gas stream has been carried out using a re-cyclable high boiling point extrant(HBE). The liquid stream containing a high boiling point entrant(HBE) scrubs the gas stream in a direct gas-liquid countercurrent contacting operation in a packed tower for the removal of said component from the gaseous stream. A packed-bed column using Pall Ring was set up in order to simulate practical conditions for the scrubbing tower. The liquid stream transported to the bioreactor is recovered and recycled to the scrubber. The model gas, which contained 400 mg/$\textrm{m}^3$ of toluene, at a rate of 100 L/min, flowed into the packed column where the scrubbing liquid trickled over the packing in countercurrent to the rising gas at 10~15L/min. The bioscrubber designed for large volume air streams containing VOCs showed removal efficiency up to 80% in an optimum operating conditions during the tests fer removing toluene from an air stream by scrubbing the air stream with HBE.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.421-432
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• 2020

This paper proposes a 2-kW solid-state power amplifier (SSPA) developed by employing power amplifier pallets designed using gallium-nitride high electron mobility transistors, which is used in S-band military radars and to replace existing traveling-wave tube amplifier (TWTA). The SSPA consists of a high-power amplifier module, which combines eight power amplifier pallets, a drive amplifier module, a digital control module, and a power supply unit. First, the amplifier module and component were integrated into a small package to account for space limitations; next, an on-board harmonic filter was fabricated to reject spurious components; and finally, an auto gain control system was designed for various duty ratios because recent military radar systems are all active phase radars using the pulse operation mode. The developed SSPA exhibited a max gain of 48 dB and an output power ranging between 63-63.6 dBm at a frequency band of 3.1 to 3.5 GHz. The auto gain control function showed that the output power is regulated around 63 dBm despite the fluctuation of the input power from 15-20 dBm. Finally, reliability of the developed system was verified through a temperature environment test for nine hours at high (55 ℃) / low (-40℃) temperature profile in accordance with military standard 810. The developed SSPA show better performance such as light weight, high output, high gain, various safety function, low repair cost and short repair time than existing TWTA.

• Journal of The Korean Association For Science Education
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• v.32 no.5
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• pp.1007-1026
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• 2012

The purpose of this study was to develop analytic framework for dialogic argumentation to show the context and flow visualizing interactions of argumentation, to be able to present quality of argumentation specifically. For this, we formulated a method of the argumentation diagram using feature of diagram simple and structurally visualizing interrelation between argument components, and then quantified quality of argumentation to argument level score on this basis. We have developed the learning material for argumentation about a vertical circular motion and used the obtained translations from applying it in developing the framework. We chose argument statements among full transcript and then coded as Toulmin's argument components, and these codes was effectively arranged and linked to show argumentation diagram. Results by argumentation diagram could be useful understanding of interactive argumentation context and the flow and present frequency, the combination of argument elements, rough qualitative level of argumentation. To quantify argumentation quality, we gave different scores to different link lines reflecting indication of argumentation quality like that diversity of argument component, justification, presence or absence of rebuttals. The process of identification of argument level is very simple, qualitative level of argumentation represented as concrete score could present various and concrete argument level. Developed analytic framework might contribute to argumentation research field, because it can present effectively dialogic argumentation result. Also, various analysis cases might guide designing an effective argumentation practice and circular motion learning.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.175-181
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• 2019

For the purpose of Application to the small radar sensor, the MMIC Chip, which is the core component of the W-band, was designed in Korea according to the characteristics of the transceiver and manufactured by 0.1㎛ GaAs pHEMT process, and compared with the MMIC chip purchased overseas. The noise figure of low noise amplifier, insertion loss of the switch and image rejection performance of the down-converted mixer MMIC chip showed better characteristics than those of commercial chips. The MMIC chip developed in domestic was applied to the transmitter and receiver through W-band waveguide low loss transition structure design and impedance matching to verify the performance after the fabrication is 9.17 dB, which is close to the analysis result. As a result, it is judged that the transceiver can be applied to the small radar sensor better than the MMIC chip purchased overseas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.4
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• pp.362-369
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• 2014

A railway SCADA system is a control systems that provide the trains with the electricity. A railway SCADA system sends commands to the RTUs(remote terminal unit) and then it gathers status information of the field devices in the RTUs or controls field devices connected with the RTUs. The RTU can controls input output modules directly, gathers the status information of the field devices connected with it, and send the information to the control center. In this way, a railway SCADA system monitors and controls the electricity power for running trains. The cyber attackers may use some vulnerabilities in the railway SCADA system software to attack critical infrastructures. The vulnerabilities might be created in the railway software development process. Therefore it need to detect and remove the vulnerabilities in the control system. In this paper we propose a new control protocol fuzzing method to detect the vulnerabilities in the DNP3 protocol based application running on VxWorks in RTU(Remote Terminal Unit) that is a component of the centralized traffic control system for railway. Debug-channel based fuzzing method is required to obtain process status information from the VxWorks.

• ALGAE
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• v.17 no.2
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• pp.105-115
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• 2002

Influences of vrious environmental factors on the eutrophication of Nakdong River were analyzed statistically using water samples collected from 1 January, 1999, to 30 September, 2001 at Namji area. The relationships between the concentration of chlorophyll α (eutrophication index) and environmental factors and were analyzed to develop a statistical model which can predict the status of eutrophication. The concentation of chlorophyll α ranged from 66.2 mg · $m^{-3}$ to 70.8 mg · $m^{-3}$ during dry winter season and the average concentration during this study period was 35.5 mg · $m^{-3}$ Namji area of Nakdong River was in the hypereutrohic stage in terms of water quality. Stephanodiscus sp. and Aulacoseria granulata var. angustissima were dominant species during the witnter to spring time and summer to autumn period, respectively. Based on the correlation analysis and the analysis of variance between chlorophyll α concentration and environmental factors, significantly high positive relationships were found in the order of BOD> pH> COD > KMnO₄ consumption > DO > conductivity > alkalinity. In contrast to these factors, significantly negrative relationships were found as in the order of $PO₄^{3-}-P$ >water level>the rate of Namgang-dam discharge > NH₃-N> the rate of Andong-dam discharge> the rate of Hapchoen-dam discharge. Based on the factors analysis of environmental factors on the concentration of chlorophyll α, we obtained five factors as follows. The first factor included water level, pH, turbiditiy, conductivity, alkalinity and the rate of Namgang-dam discharge. The second factor included water temperature DO, NH₄+-N, NO₃- -N. The third factor included KMnO₄ consumption COD and BOD. The fourth factor included the rate of Andong-dam discharge, the rate of Hapcheon-dam discharge, and the rate of Imha-dam discharge. The final factor included T-N T-P and $PO₄^{3-}-P$ > concentration. We derived two statistica models that can predict the occurrence of eutrophication based on the factors by factor analysis, using regression analysis. The first model is the stepwise regression model whose independent variables are the factors produced by factor analysis : chl α (mg · $m^{-3}$ = 42.923+(18.637 factor 3) + (-17.147 factor 1) + (-12.095 factor 5) + (-4.828 factor 4). The second model is the alternative stepwise regression model whose independent variables are the sums of the standardized main component variables:chl α (mg · $m^{-3}$ = 37.295+(7.326 Zfactor 3) + (-2.704 Zfactor 1)+(-2.341 Zfactor 5).

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.2
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• pp.129-146
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• 2014

In order to be successful in the very changeable competitive environment, the organization has to creative not only on the research and development but also on the Value Chain. Especially for the middle and small venture companies, they have to be creative on the Value Chain to get new profit. For the value innovation, kinds of factors which initiate the value innovation such as Meaningful Work, Risk Taking, Customer Orientation, Agile Decision-Making, Business Intelligence, Open Communication, Empowerment, Business Planning, Learning Organization and other similar factors should be included in the organization culture. By focusing on the above 9 factors with value innovation culture, the study practically analysis the effect of the Value Innovation Culture on the Individual Creativity, and the followings are the result of the study. Firstly, meaningful work, empowerment and risk taking are positively associated with expert knowledge which is one component of individual creativity. Secondly, open organization is confirmed to be positively associated with creative thinking skills. Thirdly, learning organization, empowerment and innovativeness are the factors which is positively associated with Intrinsic Motivation. These results have showed the employees' individual recognized Value Innovation Culture is confirmed to be helpful on inducing Individual Creativity.

• The Korean Journal of Community Living Science
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• v.17 no.4
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• pp.81-95
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• 2006

This study was made to find out how stress affect on nutrition status of the college freshmen who were experiencing physical growth and development as well as drastic emotional change. 400 male and female freshmen in 4 year colleges were surveyed respectively through the health check-up procedure for college entrance in February, In order to find out the stress in each group frustration, deprivation, lack of self efficacy, type A behavior and anxiety response were surveyed through 10 questions with total 40 points by assigning 4 points for each question. Diet Status was expressed by DDS (Dietary Diversity Score by 5 food groups) and DVS(Dietary Variety Score). 24-hrs recall method was used to find out the quantity of daily nutrient of EAR(estimated adquacy ratio) by KDRIs(Korean Dietary Recommended Intakes). Nutrition level was analyzed by Can-Pro for professionals (Korea Nutrition Association). And for the quality intake, percentage was calculated and MAR(Mean Adequacy Ratio) were produced. Highest point was obtained in the stress of anxiety with the total 40 score of 30.20, and the scores were 29.79, 28.67, and 28.39 for deprivation, type A behavior and frustration respectively. There was no difference of blood components in accordance with stress type. Stress type was divided into less sensitive group and highly sensitive one and the relationship with the blood nutrient status was observed. The difference of blood component and blood pressure in sensitive and highly sensitive groups was observed in deprivation and anxiety. The index of blood pressure(p<0.05), hemoglobin(p<0.01), HDL-cholesterol(p<0.05), and Fe(p<0.05) was high in the deprivation of sensitive group. Blood pressure and hemoglobin was high in type A of sensitive group(p<0.05). And the contents of blood triglyceride was high in the anxiety of sensitive group(p<0.001) The result of nutrition intake analysis according to stress type showed that there was low intake for energy, riboflavin, and niacin. When the degree of deprivation was high there was a lack of riboflavin intake and there was no significant difference of nutrition intake in lack of self efficacy, type A behavior and anxiety response. Thus, it is necessary for colleges to educate the students to maintain mental stability through various programs and activities after catching a kind and extent of the stress college students we meeting with like the confusion of value system, open heterosexual relationship, and the employment difficulties linked with political uncertainty and economic recession.

• Toxicological Research
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• v.28 no.1
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• pp.5-9
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• 2012

It has been shown that the accumulation of prion in the cytoplasm can result in neurodegenerative disorders. Synthetic prion peptide 106-126 (PrP) is a glycoprotein that is expressed predominantly by neurons and other cells, including glial cells. Prion-induced chronic neurodegeneration has a substantial inflammatory component, and an increase in the levels of matrix metalloproteinases (MMPs) may play an important role in neurodegenerative development and progression. However, the expression of MMPs in PrP induced rat astrocytes and microglia has not yet been compared. Thus, in this study, we examined the fluorescence intensity of CD11b positive microglia and Glial Fibrillary Acidic Protein (GFAP) positive astrocytes and found that the fluorescent intensity was increased following incubation with PrP at 24 hours in a dose-dependent manner. We also observed an increase in interleukin-1 beta (IL-$1{\beta}$) and tumor necrosis factor alpha (TNF-${\alpha}$) protein expression, which are initial inflammatory cytokines, in both PrP induced astrocytes and microglia. Furthermore, an increase MMP-1, 3 and 11 expressions in PrP induced astrocytes and microglia was observed by real time PCR. Our results demonstrated PrP induced activation of astrocytes and microglia respectively, which resulted in an increase in inflammatory cytokines and MMPs expression. These results provide the insight into the different sensitivities of glial cells to PrP.

• Journal of Life Science
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• v.30 no.8
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• pp.722-730
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• 2020

As one of the most serious health risk factors, air pollution can no longer be ignored. Particulate matter (PM) is an important and harmful component of air pollution that originates from a variety of sources. Numerous recent studies have linked PM to a range of conditions including cancer, cardiovascular, respiratory, and skin disease. The eye, despite being directly exposed to air pollution, has been investigated in very few of these studies. In this review, we describe the evidence from in vitro and in vivo studies, as well as epidemiological investigations, that supports the association between exposure to PM and the development of ocular conditions such as surface and retinal disease and glaucoma. Based on the results of previous studies, we suggest that PM exposure can lead to oxidative stress, inflammation, autophagy, and, ultimately, ocular surface disease. Nevertheless, almost no studies focus on ocular surface damage from PM while some epidemiological and clinical studies report on the posterior of the eye. However, the underlying pathological mechanisms in the posterior following PM exposure have yet to be identified, and further studies are therefore warranted of the ocular surface as well as the posterior part of the eye.