• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.2
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• pp.248-257
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• 2014

As observed in the recent war, suppression of enemy air defense operation is one of the major tactics, simultaneously conducted with high payoff target. Specifically, our air defense operation should be properly constructed, since the operating environment of our forces mostly consists with mountainous terrain, which makes detections of the enemy difficult. The effective arrangements of low altitude air defense radars can be suggested as a way of improving the detection capability of our forces. In this paper, we consider the location problem of low altitude air defense radar, and formulate it as an Integer Programming. Specifically, we surveyed the previous researches on facility location problems and applied two particularly relevant models(MCLP, MEXCLP) to our problem. The terrain factor was represented as demand points in the models. We verified the optimal radar locations for operational situations through simulation model which depicts simple battle field. In the simulation model, the performance of optimal radar locations are measured by the enemy detection rate. With a series of experiments, we may conclude that when locating low altitude air defense radars, it is important to consider the detection probability of radar. We expect that this finding may be helpful to make a more effective air defense plan.

• Journal of Climate Change Research
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• v.5 no.4
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• pp.323-329
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• 2014

Since the terrain of Korea is complex, micro- as well as meso-climate variability is extreme by locations in Korea. In particular, air temperature of agricultural fields is influenced by topographic features of the surroundings making accurate interpolation of regional meteorological data from point-measured data. This study was carried out to compare spatial interpolation methods to estimate air temperature in agricultural fields surrounded by rugged terrains in South Korea. Four spatial interpolation methods including Inverse Distance Weighting (IDW), Spline, Ordinary Kriging (with the temperature lapse rate) and Cokriging were tested to estimate monthly air temperature of unobserved stations. Monthly measured data sets (minimum and maximum air temperature) from 588 automatic weather system(AWS) locations in South Korea were used to generate the gridded air temperature surface. As the result, temperature lapse rate improved accuracy of all of interpolation methods, especially, spline showed the lowest RMSE of spatial interpolation methods in both maximum and minimum air temperature estimation.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.4
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• pp.117-124
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• 2020

This study empirically analyzed air transport trade patterns using data for 30 years between Korea and its trading partners in order to identify specific factors that determine the size of Korea's air transport trade. Independent variables were GDP per capita, capital distance between countries, country area data and number of airports. In addition, it reflected whether it is a landlocked country and whether it has joined the OECD, APEC and ASEAN+3. According to the results of the analysis, it was found that the air cargo trade pattern in Korea is proportional to GDP per capita, and the scale increases as the distance is closer. In addition, the national area and the airport capital acted as a factor in increasing air transport trade. However, whether a country is a landlocked country did not show significant results in terms of trade, exports, and imports. The OECD, APEC, and ASEAN+3 variables were found to generally increase air transport trade.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.392-393
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• 2005

Due to the temporal and spatial simultaneity and the high-frequency repetition, the data set retrieved from the satellite observation is considered to be the most desirable ones for the study of air-sea interaction. With rapidly developing sensor technology, satellite-retrieved data has experienced improvement in the accuracy and the number of parameters. Nevertheless, since it is still impossible to directly measure the heat fluxes between air and sea, the bulk method is an exclusive way for the evaluation of the heat fluxes at the sea surface. It was noted that the large deviation of air temperature in the winter season by the linear regression despite good correlation coefficients. We propose a new algorithm based on the Fourier series with which the SST and the air temperature. We found that the mean of air temperature is a function of the mean of SST with the monthly gradient of SST inferred from the latitudinal variation of SST and the spectral energy of air temperature is related linearly to that of SST. An algorithm to obtain the air temperature over the sea was completed with a proper analysis on the relation between of air temperature and of SST. This algorithm was examined by buoy data and therefore the air temperature over the sea can be retrieved based on just satellite data.

• The Journal of the Acoustical Society of Korea
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• v.19 no.2
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• pp.3-7
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• 2000

This paper is on the sensitivity characteristics of a concentric composite mandrel type fiber optic acoustic sensor with inclusion of an air cavity With the finite element method, we have analyzed sensitivity variation of the sensor in relation to its geometrical factors such as thickness of the air cavity, thickness of the foaming layer, and the ratio of inner diameter/outer diameter of the mandrel. Results of the analysis suggest a thicker air cavity, a thinner foaming layer, and a smaller ratio of the inner diameter/outer diameter of the mandrel to be desirable for higher sensitivity. The sensor structure designed with the above rules provides the sensitivity of about 0.8dB higher than that of a normal concentric composite mandrel sensor without the inherent air cavity.

• KIEAE Journal
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• v.10 no.3
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• pp.37-42
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• 2010

Together with the concern about the indoor air quality as sick house syndrome, the Ministry of Environment announced "Indoor Air Quality Control Law for the Multi Purpose Facility," which made the interests to be focused in the urgent understanding of current condition and preparation of measures about the indoor air pollution. The law was revised to obligatorily notify the amount of Formaldehyde and Volatile Organic Compounds in the case of newly constructed apartments with more than 100 houses. School also have its own indoor air quality guideline. Indoor air quality in school is very important because, children who very weak to indoor pollutants reside long time in there. The purpose of this paper is to to survey indoor air quality in school by field measurement. Field measurements were performed in 11 schools which were selected from 3 major cities(Incheon, Dae-jeon, chuncheon) in korea, Totally concentration of indoor pollutants were determined in 32 classroom. Target air pollutants were TVOC, formaldehyde, dust, CO, CO2. For the result of this investigation, Indoor air quality in classroom was very poor and it was found that some pollutants(TVOC, float bacteria) exceed the guideline.

• Journal of the military operations research society of Korea
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• v.35 no.3
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• pp.1-15
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• 2009

Central supply depot of Air Force has been receiving and storing the goods from the inside and outside of the country. And it also has been distributing the goods to the air base by air, rail, road, etc. These goods have been called central goods. Among these central goods, 10% of them are transported by air and the amount of freight is increasing day by day. So, air transportation in the Air Force has been more important than ever. But, studies of demand estimation for activating air transportation are very difficient. This study verified the main factors affecting to air transportation and the function of regression model will be useful data for estimating air freight demand.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.11 no.4
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• pp.22-27
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• 2015

Quality characteristics of Shiitake mushroom using two types of dryers, energy-efficient heat pump hot-air dryer and electric heater hot-air dryer were compared. Energy consumed during drying by heat pump hot-air dryer and electric heater hot-air dryer were 22.8 kWh and 28.9 kWh, respectively. Total polyphenol content of heat pump hot-air dryer and electric heater hot-air dryer after drying were $290.55{\pm}10.56ppm$ and $192.99{\pm}6.53ppm$, respectively. No differences were observed between dryers in reconstitution rate and browning ratio after drying. Also, there were no differences between dryers in color value and ${\Delta}E$ value after drying. Shiitake mushroom drying at $45^{\circ}C$ by heat pump hot-air dryer was proved to be more efficient in energy consumption than by electric heater hot-air dryer.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.7
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• pp.482-491
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• 2010

In conventional air-handling units, when the circulated air from the air-conditioned space pass through the cooling coil, the air is over-cooled to eliminate the moisture as well as to decrease the temperature. The purpose of this study is to estimate the thermal performance and energy saving of the cooling/reheating system using heat exchanger which can save both cooling energy and reheating energy by exchanging heat between the cooled air and reheated air. The energy balance equations to estimate the state of the air for each components were provided and the heat transfer rates and the energy saving rates for the system were calculated from the equations. The results showed that the energy saving was up to 40% under present conditions, and saving rates were significantly affected by the air velocity, inlet conditions and the effectiveness of heat exchanger.

• Journal of the Korean Solar Energy Society
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• v.31 no.4
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• pp.87-94
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• 2011

To develop the solar air heater, prototype of solar heater with test room set up on the roof of test chamber and operation characteristics were examined with solar radiation. Air induced from outside was supplied by a blower and also heated air was supplied to the test chamber(size of 1,000mm(inwidth)*2,000mm(in length)*2,000mm(in depth)) established already for performance. It was clear that almost 30% of solar radiation was converted into effective heating energy at maximum and the highest air temperature was $46^{\circ}C$, and thus solar air heater in winter could be used as an possible alternative heating system in building. Furthermore, heat energy obtained from solar air heater can be applied to regenerate absorber in the solar desiccant cooling system.