• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.12
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• pp.927-934
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• 2015

In this study, we numerically investigated the concentration characteristics of a linear Fresnel reflector system that can drive a solar thermal absorption refrigeration system to be installed in Saudi Arabia. Using an optical modeling program based on the Monte Carlo ray-tracing method, we simulated the concentrated solar flux, concentration efficiency, and concentrated solar energy on four representative days of the year - the vernal equinox, summer solstice, autumnal equinox, and winter solstice. Except the winter solstice, the concentrations were approximately steady from 9 AM to 15 PM, and the concentration efficiencies exceed 70%. Moreover, the maximum solar flux around the solar receiver center changes only within the range of $13.0{\sim}14.6kW/m^2$. When we investigated the effects of the receiver installation height, reflector width, and reflector gap, the optimal receiver installation height was found to be 5 m. A smaller reflector width had a greater concentration efficiency. However, the design of the reflector width should be based on the capacity of the refrigeration system because it dominantly affects the concentrated solar energy. The present study was an essential prerequisite for thermal analyses of the solar receiver. Thus, an optical-thermal integration study in the future will assist with the performance prediction and design of the entire system.

• The Korean Journal of Ecology
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• v.22 no.3
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• pp.139-144
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• 1999

In order to clarify ecological survival strategy of Rumex crispus community dominating under contaminated area of lower region of Kumho riverside including Chimsangyo (CS), Paldalgyo (PD), Talseochon (TS) and Kumhogyo (KH), we analyzed the content of heavy metals and inorganic matter and vegetative growth. R. crispus showed rapid formation of community by high growth rate, high T/R ratio and showed maximum T/R ratio at the contaminated area Talseochon. Nitrogen and phosphorus contents in R. crispus showed high value in shoot than that of root. T/R ratio of nitrogen and phosphorus showed 3.1∼3.6 and 1.5∼4.5 for the early growth stage, and 6.7∼17.3 and 3.9∼8.3 for the late one, respectively. The absorbed heavy metals by riot were translocated to shoot, the heavy metal content in shoot higher than those in root of Cu, Zn, Fe, and Pb for 3.6, 1.7, 1.5 and 4.8 times, respectively. Distribution ratio of the heavy metals in each organ showed 61∼85% and 15∼39% for shoot and root, respectively. R. crispus accumulated heavy metals in the order of Fe>Zn>Cu>Pb in shoot, and showed maximum values of Cu, Zn, Fe and Pb for 89.7, 376.6, 2946.1 and 13.2 ㎍/g dw, respectively at Talseochon in April. A physiological and morphological characteristics of R. crispus showed thickened leaf, increased water content above 80% and rapid growth of shoot. R. crispus showed ecological adaptation to the contaminated area by transportation of heavy metals and inorganic matter to shoot, and by accumulation of Ca ion in root.

• Transactions of the KSME C: Technology and Education
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• v.2 no.1
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• pp.47-55
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• 2014

A new concept of an Eco-friendly desalination method is introduced in this study. The main idea of the desalination method of seawater is the condensation of the vaporized seawater by solar heat energy on the surface of seashore. The wind turbine blade plays a role of heat exchanger condensing the vaporized water in the air. In this analytical study, the availability of the proposed desalination system was studied. First, an analytical condensation theory of the vaporized water in air was arranged and the parametric study was conducted to estimate the amount of freshwater produced from the system with the change of the temperature difference between the humid air and turbine blade, and the relative humidity in air, and wind speed. From the analytical calculation, 2,927(ton/year) of freshwater was produced at the vertical-type wind turbine (Diameter=4m, Height=3m) as the relative humidity is 100%, the temperature difference between the impeller blade and the humid air is $40^{\circ}C$ and the wind speed is 10m/s.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.42-47
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• 2006

Direct medical control by medical doctors is an essential part of emergency medical services system (EMSS). However, the indications are not specifically defined, even in 119 system with their own medical control team. The Seoul Metropolitan Fire and Disaster Management Department has operated internal medical consultation services on its own since January 2004. Based on the experiences from these services, we reviewed the cases of the direct medical consultation and establish the indications for direct medical control. And we presumed the demand of direct medical control with the established indications. The crews of 119 in Seoul made 793 calls to Medical Control Team during November 2004. We reviewed all of the calls according to the level of consciousness (AVPU), the kinds of emergency care done by crews during transport (10 categories), and the mechanisms of injuries (9 categories). The need for direct medical control was judged by authors with reviewing the records reported by the crews and control teams. Among 23 items, 14 items assigned as the indications, which were abnormal level of consciousness (VPU), 6 kinds of emergency care, and 5 mechanisms of injures. The sum of the three of them, 7,782 cases (45.9%), was in need of direct medical control. In conclusion, about half of the patients transported by 119 crews in Seoul require direct medical control. The need for the direct medical control in Seoul was estimated as many as 260 calls per day. To fulfill the need for direct medical control and to provide a effective medical control, the direct medical control should be accomplished through the communications between the crews and the medical staffs in the local hospitals.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.4
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• pp.439-444
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• 1983

Effects of temperature and soil moisture on the growth and grain-filling of two wheat cultivars were investigated. Two levels of temperature; day 3$0^{\circ}C$/night $25^{\circ}C$ and day 2$0^{\circ}C$/night 15$^{\circ}C$ and two levels of soil moisture; stressed (45-50% of F.C.) and non-5tressed (50-60% of F.C.) were imposed in the green house from heading date to the maturity and grain weight, chlorophyll content of flag leaf and leaf area index(LAI) were observed at weekly interval. Grain maturation was faster in the high temperature than those in the lower temperature. Chlorophyll content of flag leaf and LAI decreased rapidly in the high temperature and chlorophylls disappeared at the 20 days after heading. In lower temperature condition, slower decrements were shown in chlorophyll content and it remained until 45 days after heading. Grain weights in the high and optimum temperature conditions reached to maximum values at 29 days and 45 days after heading, respectively. Differences of grain weight and chlorophyll content of flag leaf were not significant between stressed and non-5tressed soil moisture condition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.9
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• pp.757-762
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• 2012

In general, an ordinary CCTV camera has equipped with 24 frames per second. This camera is not capable of capturing an image of bullet trace which has speed about 1km per second. In spite of these difficulties, by means of the stereographical projection, a long distance trace is able to be contained in one image. Currently, to capture a series of image of an object with high speed, it is usual to use one of the complicated camera with high shutter speed or computerized devices with capability of controlling shutter timing with slightly different capture time. This paper proposed a monitoring tracer bullet single camera system equipped convex mirror trying to see whether or not a normal set of camera and convex mirror is capable of shooting on target located in as far as 250m.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.105-111
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• 2013

The present study has been carried out to reduce the heat loss from a built in refrigerator by using reverse heat loss method to discern the region with larger heat loss. To perform this purpose, an infrared thermographic camera has been used to measure the surface temperature of the refrigerator and tried to improve the heat loss near the ice dispenser. The numerical heat transfer analysis also has been accomplished to clarify the heat transfer mechanism near the ice dispenser. The possible applicable method to reduce heat loss was increasing the curvature radius at the ice dispenser corner. The curvature radius has been changed from 0mm to 40mm to see the effect of the curvature at the corner. From the present research, the optimal curvature radius for the reduction of heat loss at the ice dispenser could be 30mm.

• Journal of Korean Library and Information Science Society
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• v.36 no.1
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• pp.47-69
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• 2005

The aim of this paper is to evaluate the text of six alternative versions of Korean fairy tale The Sun and the Moon. So the author took a textual bibliographical study of those versions in a comparative analysis of titles, backgrounds, characters. styles and functions of them. On the basis of this comparative analysis, the version of Hyo-Sun Eu was selected as a good text. In the version of Hyo-Sun Eu. if the helper In the story, King of Heaven represented in the form of Taoism would change into Heaven represented in the form of God, and the literary style change into the colloquial style, and the last scene that the Sun Brother turns to the Sun Sister and the Moon Sister to the Moon Brother would be removed, this version will be the best one.

• International Commerce and Information Review
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• v.16 no.5
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• pp.387-407
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• 2014

The purpose of this study was to substantially survey the satisfaction of resident companies in Incheon Free Economic Zone to improve the investment environment of Incheon Free Economic Zone to attract more resident companies. This study implies that additional industrial lots should be secured and the restrictions against small/medium companies should be alleviated so they can grow into strong companies considering that the resident companies in Incheon Free Economic Zone are highly satisfied with their business in Incheon Free Economic Zone. As resident companies' satisfaction with administrative support, recruitment, and industrial infrastructure is low, Incheon Free Economic Zone Authority should understand and improve the specific complaints of resident companies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1202-1209
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• 2003

With explosive growth of Internet users, the market share of electronic commerce becomes wider. Therefore the Internet is standing in the spotlight of a new medium of advertisement, and several Internet advertising methods have been implemented. However the banner advertising that is the typical internet advertising method is showing low click rate because of user's unconcern. Accordingly we propose a new Internet advertising method that makes expose advertising content on the background of web browser when user puts mouse pointer over a specified text. Internet users are willing to click a interesting text, just at that moment the advertising content is appeared on the background of web browser. Therefore we could expect high effectiveness of advertising and moreover after clicking the text, the advertising content is shown continually on the web browser. The proposed method, unlike banner advertising, various shapes of image can be applied and makes use of whole background of web page.