• The Korean Journal of Physiology and Pharmacology
• /
• v.7 no.5
• /
• pp.275-278
• /
• 2003

Antioxidative activity is an important factor in inhibiting oxidative stress. The usual methods for determining antioxidative activity are time-consuming and cumbersome. They are also indirect processes that use biological material such as brain or liver microsome. This study therefore proposed a new method. Redoxpotential was determined using galvanic cell with or without the addition of various antioxidants or herbal extracts in zinc sulfate solution. The result was compared with the results from the TBA method and the peroxide value from sodium thiosulfate titration. All methods showed significant and dose-dependent enhancement of antioxidative activity by adding ascorbic acid, quercetin, ginseng, or gingko biloba extract. The result of redox potential using galvanic cell showed the smallest standard deviation and took the shortest time among the three methods. Therefore, the antioxidative potential of chemical substances and herbal extracts can be determined simply, directly and accurately in a short period of time using galvanic cell.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.8
• /
• pp.770-777
• /
• 2004

Fouling and cleaning tests are performed for a uniquely designed 7,000 ㎉/hr fluidized bed heat exchanger for exhaust gas heat recovery. Fuel rich condition is maintained in the combustor for a limited time period to generate soot that is to be deposited on the heat transfer surfaces (fouling) and 600 Um glass beads are circulated inside the heat exchanger system for cleaning and enhancing the heat transfer performance. According to the present experimental study, performance degradation mode could be monitored and the effect of particle circulation on the heat transfer improvement could be identified. Through the present study, it is demonstrated that circulating particles contribute not only to the fouling reduction in gas side, but also to the heat transfer enhancement of the unit, while other possible aging factors including water side corrosion seemed to contribute to the accumulated performance deterioration.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.12
• /
• pp.88-96
• /
• 2015

This paper describes a new method for enhancing the accuracy of network analysis applications in energy management systems. Topology processing, state estimation, power flow analysis, and contingency analysis play a key factor in the stable and reliable operation of power systems. In this respect, the aim of topology processing is to provide the electrical buses and the electrical islands with the actual state of the power system as input data. The results of topology processing is used to input of other applications. New method, which includes the topology error analysis based on inconsistency check, coherency check, bus mismatch check, and outaged device check is proposed to enhance the accuracy of network analysis. The proposed methodology is conducted by energy management systems and the Korean power systems have been utilized for the test systems.

• Journal of Construction Engineering and Project Management
• /
• v.7 no.3
• /
• pp.39-55
• /
• 2017

Preeminent performance of construction industry are unattainable with poor productivity resulting in time and cost over runs. Enhancement in productivity cannot be achieved without identifying and analyzing factors that adversely affect productivity. The objective therefore is to propose a productivity analysis model to quantify the probability of effect of factors influencing productivity by using fuzzy logic incorporated with relative importance index method, for various types of construction projects. To achieve this objective, a questionnaire survey was carried out targeting respondents of Indian construction industry, from four distinct projects, namely, residential, commercial, infrastructure and industrial projects. Based on questionnaire administered, the relative importance and ranks of factors demonstrated using relative importance index method. Probability assessment model to analyze productivity was then developed by using Fuzzy Logic Toolbox of MATLAB. The applicability of the proposed model was tested in seven construction projects and the probability of impact of factors on productivity evaluated. The results of application of model in the construction firms infers that the most contributing factor groups for most of the projects were discerned to be manpower, motivation and time group.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2001.05a
• /
• pp.100-105
• /
• 2001

The present paper is to present the results of studied of pressure drop in annuli with corrugated and spirally fluted inner tubes for the turbulent flow regime. To understand the underlying physical phenomena responsible for heat transfer enhancement, flow mechanism documented elsewhere are combined with pressure drop measurements to confirm the friction factors obtained from the annuli with the grooved inner tubes for the Reynolds number of 1000 to 8000. Friction factors were found to be functions of trough depth, pitch and angle, and the annulus radius ratio. friction factor increases in the spirally fluted tubes were larger than those in the corrugated tubes.

• Management & Information Systems Review
• /
• v.22
• /
• pp.231-254
• /
• 2007

This study is analyzed how much protected buying and selling service on Auction site affects to the customers' satisfaction. According to the results of it, First, considering that the aspects of the reliability of the Auction site, trade factor affects to the reliability of Auction website. Second, it shows the organized security of the site affects to the reliability. and it could be explained the escrow service has brought the customers to get the reliability of Auction website. Third, the execution of purchasing contract on website affects to the customers' satisfaction. and it makes customers confirm and rely on Auction. For example, carrying out of the escrow service, enhancement of the system for the policies for the buying protection of customers, and various concerns and efforts for the execution of the purchasing contract and so on affect to the customers' satisfaction.

• YAKHAK HOEJI
• /
• v.43 no.5
• /
• pp.635-641
• /
• 1999

In this study, we investigated the immunopotent activities of lepidan, a water soluble proteoglycan from Lentinus lepideus. To examine whether lepidan may affect nonspecific immune responses, we determined the effect on the production of nitric oxide (NO). Lepidan effectively increased the NO production in IFN-${\gamma}$ and LPS triggered RAW 264.7 cells. To further demonstrate the evidence that lepidan activates various immune cells, we determined the alkaline phosphatase activity, plaque-forming cell number and secretion of interleukine-4 (IL-4) and granulocyte/macrophage-colony stimulating factor (GM-CSF) after lepidan treatment in murine splenocytes. The results showed that lepidan increased alkaline phosphatase activity and the number of plaque-forming cells, which indicates that lepidan can lead B lymphocytes to late stage of differentiation. Also, when the splenocytes were cultured with lepidan for 48 hr, the level of IL-4 and GM-CSF in the supernatant dramatically increased. Taken together, these data suggest that lepidan is a biological response modulator that is able to activate immune responses.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.183-186
• /
• 1999

A 900 71Hz RF band-pass amplifier for wireless communication systems is designed and fabricated. HSPICE simulation results show that the amplifier can achieve a tunable center frequency between 880 MHz and 920 MHz. The gain of designed amplifier is 19 dB at Q=88, and the power dissipation is about 61 mW under 3 V power supply by using the spiral inductor with negative-7m circuit and center frequency tunning circuit. The designed band-pass amplifier is implemented by using 0.6 um 2-poly-3-metal standard CMOS process.

• Journal of the Korean Home Economics Association
• /
• v.49 no.7
• /
• pp.39-49
• /
• 2011

The purpose of this study was to examine the relationship between the attitude towards well-being and life satisfaction, to investigate the effect of healthy lifestyle and attitude towards well-being on life satisfaction, and to explore the differences in well-being lifestyle factors, well-being attitude, and life satisfaction against demographic variables. This study gave a questionnaire survey to adults between the ages of 10 and 60 who lived in the Seoul, Daegu and Kyungbuk regions of South Korea. Data collected from the 285 respondents was analyzed using descriptive statistics, correlation, t-tests, ANOVA, factor analyses, and regression analysis. The lifestyle for well-being was categorized into four areas, social welfare oriented activity, use of environmentally friendly products, self-esteem enhancement, and sports activity. Three of these factors were significantly correlated with the attitude towards wellbeing. The results of the regression analysis suggested that healthy lifestyle and attitude towards well-being affected people's life satisfaction.

• Journal of the Korean Institute of Rural Architecture
• /
• v.17 no.3
• /
• pp.63-70
• /
• 2015

Recently, the rural village development projects are proceeding as enhancement of the rural landscape as the interest toward rural tourism and rural immigrant has increased. However, the projects are solely to support construction of community space and there has been a lack of community facility remodeling in term of both deterioration facilities and abandoned facilities. Thus in this study proposes rural community facility remodeling process to utilize remodeling of rural deterioration facilities and abandoned facilities. For setting rural community remodeling process, this study analysed preceding research data and suggested rural community remodeling process stage ; planning, spacial resolution, remodeling factor analysis, implementation, maintenance control, based on research data. For systematic performed this process, this study regulated role of local resident, expert and local government on remodeling process stage.