• Korean Journal of Remote Sensing
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• v.33 no.5_3
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• pp.855-866
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• 2017

Several research cases using remote sensing methods to analyze changes of storage and dynamics of groundwater aquifer were reviewed in this paper. The status of groundwater storage, in an area with regional scale, could be qualitatively inferred from geological feature, surface water altimetry and topography, distribution of vegetation, and difference between precipitation and evapotranspiration. These qualitative indicators could be measured by geological lineament analysis, airborne magnetic survey, DEM analysis, LAI and NDVI calculation, and surface energy balance modeling. It is certain that GRACE and InSAR have received remarkable attentions as direct utilization from satellite data for quantification of groundwater storage and dynamics. GRACE, composed of twin satellites having acceleration sensors, could detect global or regional microgravity changes and transform them into mass changes of water on surface and inside of the Earth. Numerous studies in terms of groundwater storage using GRACE sensor data were performed with several merits such that (1) there is no requirement of sensor data, (2) auxiliary data for quantification of groundwater can be entirely obtained from another satellite sensors, and (3) algorithms for processing measured data have continuously progressed from designated data management center. The limitations of GRACE for groundwater storage measurement could be defined as follows: (1) In an area with small scale, mass change quantification of groundwater might be inaccurate due to detection limit of the acceleration sensor, and (2) the results would be overestimated in case of combination between sensor and field survey data. InSAR can quantify the dynamic characteristics of aquifer by measuring vertical micro displacement, using linear proportional relation between groundwater head and vertical surface movement. However, InSAR data might now constrain their application to arid or semi-arid area whose land cover appear to be simple, and are hard to apply to the area with the anticipation of loss of coherence with surface. Development of GRACE and InSAR sensor data preprocessing algorithms optimized to topography, geology, and natural conditions of Korea should be prioritized to regionally quantify the mass change and dynamics of the groundwater resources of Korea.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.4
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• pp.216-226
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• 2019

This study was to investigate the effect of the horse grazing intensity on the vegetation of the S. quelpaertensis, and the physiological changes of the horse. This experiment was conducted at the community of the S. quelpaertensis (altitude of 550m) with the grazing intensity of 1.0AU(500kg), 1.5AU(750kg) and 2.0AU(1,000kg) at 30m × 30m for one week, and then the growth characteristics of the S. quelpaertensis, the changes of the vegetation, the damages on trees and the changes in the physiological characteristics of the horses was investigated and compared before and after the horse grazing. As the results, the 2.0AU grazing land showed that the culm number had the inverse correlation (r=-0.902, P<0.01) to the other lands and the species diversity index of lower-level vegetation showed the correlation (r=0.773, P<0.01) as increasing the grazing intensity.

• Journal of Soil and Groundwater Environment
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• v.13 no.2
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• pp.44-53
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• 2008

The efficiences of mineral acid (HCl), neutral salts ($CaCl_2$), and chelating agent (citric acid and $Na_2$-EDTA) were tested for extracting heavy metals from open burning and open detonation (OBOD) site soil. The extraction efficiencies of Cd, Cu, Pb and Zn from soil for various extractants were in the order of HCl > citric acid > $Na_2$-EDTA > $CaCl_2$, HCl (1.0 M) extracted effectively 82%, 86%, 80%, and 46% of initial total concentrations of Cd, Cu, Pb, and Zn, respectively. Significant negative correlations were observed between pH of extractant and amount of extracted heavy metals. Initially, examined heavy metals were predominantly bound to carbonate and Fe, Mn-oxide fraction. Though the significant amount of carbonate and Fe, Mn-oxide bounded metals were removed but a significant amount remained metals shifted to exchangeable (more mobile) fraction by HCl and citric acid extraction. The increased mobility of remaining metals could be problematic for water resources, thus careful management is needed to control the movement of heavy metals.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.3
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• pp.152-159
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• 2009

This study was carried out to investigate optimum application rate with mixed organic fertilizer for chemical fertilizer alternative where the paddy rice (Chucheong) was cultivated in clay loam of paddy field. The mixed organic fertilizer were applied at 0, 50, 100 and 150% levels of recommended nitrogen by soil testing plot compared with plot of chemical fertilizer (nitrogen, phosphate and potash), respectively. The ammonium nitrogen content in paddy soil and surface water of mixed organic fertilizer 100% plot were higher than chemical fertilizer plot. The absorbed amount of nitrogen and nitrogen use efficiency by rice plant in mixed organic fertilizer 100% plot were higher than chemical fertilizer plot. The number of tillers on rice at 30 days and 60 days after transplanting mixed organic fertilizer 100% plot were many more than chemical fertilizer plot. The milled rice yield of mixed organic fertilizer 100% plot was increased by 4% than chemical fertilizer plot. The optimum application rate of mixed organic fertilizer was as follows ; $OAR_{MOF}(Mg\;ha^{-1})=[(NAR_{ST}{\div}NC_{MOF}/1,000{\times}0.93)/1,000]$ ($OAR_{MOF}$ : Optimum application rate of mixed organic fertilizer, NARST : Nitrogen application rate($kg\;ha^{-1}$) by soil testing, $NC_{MOF}$ : Nitrogen content($g\;kg^{-1}$) of mixed organic fertilizer, and $0.93:124.3kg\;ha^{-1}/133.0kg\;ha^{-1}$, respectively).

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.247-259
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• 2011

It is necessary to collect, manage and standardize defense and technology terminologies which are used by defense-related agencies in the field of national defense science and technology. The standardization of terminology dictionary can eliminate confusion about terminology and increase accessibility for the terminology by offline and online services. This study focuses on building national defense science and technology terminologies, publishing dictionary including them, and improving information analysis in defense area. as well as take advantage of offline and online services for easy accessibility for the terminology. Based on the results of this study, the terminology data will be used as follows; 1) Defence science and technology terminology databases and its publication. 2) Information analysis in military fields. 3) Multilingual information analysis translated terms in the thesauri. 4) Verification on the consistency of information processing. 5) Language resources for terminology extraction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.541-546
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• 2020

The surveillance radar for naval ships is an essential equipment of a battle system that executes the detection and tracking of targets, and the shooting support function; it calculates the three-dimensional track of the target range, azimuth, and altitude to carry out its duty. The surveillance radar consists of an antenna, a transceiver, a processing unit, and an air dryer section. The radar radiates the transmission signal on the antenna section, receives the reflected signal from the target, and amplifies the signals on the transceiver section. The signal received from the antenna is used to provide the operator with target information in various ways. This study identified the display problems when the information about the target is displayed through the radar. The causes of the problems were analyzed and improved. The tracking disappearance phenomenon caused by the altered-course of the ship was improved on the TWS tracking algorithm. The validity of the improved TWS tracking algorithm was confirmed by the normal condition of the target status on the B-scope.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.84-89
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• 2014

Worldwide Interoperability for Microwave Access (WiMAX) is an efficient technology for 20th century communication system. The technology provides broadband speed without the need for cables and is based on the IEEE 802.16 standard(also called Wireless MAN). Mobile WiMAX is defined as IEEE802.16e which is advanced and efficient technology for mobile telecommunication rather than GSM, CDMA technology. In this work link budget calculation for WiMAX have been done. Cell range have been calculated over digital modulations and they are BPSK, QPSK and QAM. Here different types of models like Cost 231 model have been used for different types of areas like open, rural and urban areas and Erceg-Greenstein model for sub-urban areas. Effect of various parameters like frequency, base station antenna height, transmission power and SNR over cell range have been studied. Analysis have done for both uplink and downlink.

• Journal of Cadastre & Land InformatiX
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• v.44 no.2
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• pp.209-230
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• 2014

There are three forms of REITs company in Korea that was first introduced in 2002. Each REITs have been listed on the KRX, its characteristics are different, but it is classified as a REITs company in all events. REITs current methods are applied uniformly manner that does not reflect the characteristics of the individual. REITs some, that is not seen unlike legislative intent, it is delisted, such as generating an investment loss of investors. In this study it is an object of the invention from the point of view of REITs business validity, to draw up operational support aggressive plans of the scheme. By improving the PF assesment system, to improve the relevance of REIT business and presenting policy direction to the activation of REITs. Through the sophistication of real estate finance utilizing REITs, policy for proper investment of general investors REITs funds were listed with the smooth flow must be realized. The results of this study, it can be utilized as basic data for policy to reflect the real estate policy for activation of the indirect financial investments.

• Tunnel and Underground Space
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• v.26 no.1
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• pp.24-31
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• 2016

Recently, many studies have been conducted to use fixed-wing and rotary-wing unmanned aerial vehicles (UAVs, Drones) for topographic surveying in open-pit mines. Because the fixed-wing and rotary-wing UAVs have different characteristics such as flight height, speed, time and performance of mounted cameras, their results of topographic surveying at a same site need to be compared. This study selected a construction site in Yangsan-si, Gyeongsangnam-do, Korea as a study area and compared the topographic surveying results from a fixed-wing UAV (SenseFly eBee) and a popular rotary-wing UAV (DJI Phantom2 Vision+). As results of data processing for aerial photos taken from eBee and Phantom2 Vision+, orthomosaic images and digital surface models with about 4 cm grid spacing could be generated. Comparisons of the X, Y, Z-coordinates of 7 ground control points measured by differential global positioning system and those determined by eBee and Phantom2 Vision+ revealed that the root mean squared errors of X, Y, Z-coordinates were around 10 cm, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.76-83
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• 1985

A hypothesis that artificial reforming of corn canopy could improve solar light penetration and dry matter production was tested in corn fields (var. Suwon 19) with three planting densities; low (60 ${\times}$ 40cm), medium (60 ${\times}$ 24cm) and high (60 ${\times}$ 16cm). Natural canopy was found that leaf orientations were even over all azimuth but somewhat inclined toward north-south direction and leaf angle ranged 38$^{\circ}$ to 71$^{\circ}$ from horizontal surface. Reforming corn canopy included following treatments: 1) natural canopy planted in north-south rows (natural canopy), 2)east-west plane canopy planted in north-south rows (E-W canopy), 3)east-west plane canopy and upright leaves in north-south rows, 4)north-south plane canopy (N-S canopy) in east-west rows. After corn plots were installed with training system by supporting poles and connecting wires, corn leaves were induced to a reforming direction and tied on wire. Average light intensity at the mid-point of plant height showed 5-10% increases in E-W canopy and in E-W canopy plus upright leaves, but a 2-10% decrease in N-S canopy from natural canopy. At yellow ripe stage, total dry wt. was increased in E-W canopy but not in N-S canopy. The E-W canopy produced 3-10% more grain yield than natural canopy. Though E-W canopy plus upright leaves yielded less at low density, it yielded up to 10% more at higher density. The N-S canopy yielded similar to low compared with natural canopy. These results suggests that reforming canopy toward solar incident direction increases light penetration into lower canopy, photosynthetic efficiency and grain yield, especially at high planting density in corn.