• Proceedings of the Korea Society of Environmental Biology Conference
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• 2001.12a
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• pp.89-89
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• 2001

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.6
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• pp.517-526
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• 2015

Among the various image fusion or pan-sharpening methods, those wavelet-based methods provide superior radiometric quality. However, the fusion processing is not only simple but also flexible, since many low- and high-frequency sub-bands are often produced in the wavelet domain. To address this issue, a novel DT-CWT (Dual-Tree Complex Wavelet Transform) proportional to the fusion method by a WZP (Wavelet Zero-Padding) is proposed. The proposed method produces a single high-frequency image in the spatial domain that is injected into the LRM (Low-Resolution Multispectral) image. Thus, a wavelet domain fusion can be simplified to spatial domain fusion. In addition, in the proposed DT-CWTP (DT-CWT Proportional) fusion method, it is unnecessary to decompose the LRM image by adopting WZP. The comparison indicates that the proposed fusion method is nearly five times faster than the DT-CWT with SW (Substitute-Wavelet) fusion method, meanwhile simultaneously maintaining the radiometric quality. The conducted experiments with WorldView-2 satellite images demonstrated promising results with the computation efficiency and fused image quality.

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.4
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• pp.252-267
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• 2015

Offshore structures might encounter several environmental and operating conditions during their lifetime of several decades. In order to predict the dynamic behavior of offshore structures, several simulation cases should be considered to deal with all the combinations of ocean environments and operating conditions. Because a sophisticated time-domain coupled dynamic analysis requires an extremely large amount of computational time to handle all the possible cases, an efficient preliminary process to prescreen the probability of severe environmental conditions can be helpful in downsizing the number of simulation cases and computational effort. In this study, a prescreening procedure to reduce the number of environmental conditions for dynamic analyses of offshore structures is proposed. For the efficiency of the procedure, frequency-domain theories were adopted to estimate the platform offset, using quasi-static analyses in line tension prediction. The results were validated by comparing with those of dynamic analysis coupled between platform and mooring lines, and reasonable agreement was observed. In addition, the characteristics of environmental conditions classified to be severe to the system were investigated through the application of the developed prescreening scheme to several actual environmental conditions.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.6
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• pp.437-446
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• 2023

We propose a transient evaluation scheme using a pressure measurement in a complicate pipeline systems. Conservation of mass and momentum equations in time domain can be transformed into a pressure head and flowrate relationship between upstream and downstream point in frequency domain. The impedance formulations were derived to address measured pressure at downstream to evaluate of flowrate or pressure head at any point of system. Both branched pipeline element and looped pipeline element can be generally addressed in the platform of the basic reservoir pipeline valve system. The convolution of time domain response function with measured pressure head from a downstream point provides flowrate or pressure head response in any point of the designated pipeline system. The proposed method was validated through comparison between traditional method of characteristics and the proposed method in several hypothetical systems.

• Structural Engineering and Mechanics
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• v.20 no.3
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• pp.347-362
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• 2005

The input energy to a base-isolated (BI) building during an earthquake is considered and formulated in the frequency domain. The frequency-domain approach for input energy computation has some notable advantages over the conventional time-domain approach. Sensitivities of the input energy to the BI building are derived with respect to uncertain parameters in the base-isolation system. It is demonstrated that the input energy can be of a compact form via the frequency integration of the product between the input component (Fourier amplitude spectrum of acceleration) and the structural model component (so-called energy transfer function). With the help of this compact form, it is shown that the formulation of earthquake input energy in the frequency domain is essential for deriving the sensitivities of the input energy to the BI building with respect to uncertain parameters. The sensitivity expressions provide us with information on the most unfavorable combination of the uncertain parameters which leads to the maximum energy input.

• BMB Reports
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• v.34 no.1
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• pp.73-79
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• 2001

Transcriptional activation domains are known to be inherently "unstructured" with no tertiary structure. A recent NMR study, however, has shown that the transactivation domain in human p53 is populated with an amphipathic helix and two nascent turns. This suggests that the presence of such local secondary structures within the overall "unstructured" structural framework is a general feature of acidic transactivation domains. These pre-existing local structures in p53, formed selectively by positional conserved hydrophobic residues that are known to be critical for transcriptional activity, thus appear to constitute the specific structural motifs that regulate recognition of the p53 transactivation domain by target proteins. Here, we report the results of a NMR structural comparison between the native human p53 transactivation domain and an inactive mutant (22L,23W$\rightarrow$22R,23S). Results show that the mutant has an identical overall structural topology as the native protein, to the extent that the amphipathic helix formed by the residues 18T 26L within the native p53 transactivating domain is preserved in the double mutant. Therefore, the lack of transcriptional activity in the double mutant should be ascribed to the disruption of the essential hydrophobic contacts between the p53 transactivation domain and target proteins due to the (22L,23W$\rightarrow$22R,23S) mutation.

• Journal of Environmental Science International
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• v.19 no.2
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• pp.157-170
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• 2010

Air mass recirculation is a common characteristic in the coastal area as a result of the land-sea breeze circulation. This study simulates the recirculation of air mass over the Gwangyang Bay using WRF-FLEXPART and offers a basic information about the effective domain size that can reflect recirculation. For this purpose, WRF is set up four nested domains and three cases are selected. Subsequently FLEXPART is operated on the basis of WRF output. During the clear summer days with weak wind speed, particles that emitted from Yeosu national industrial complex and Gwangyang iron works flow into emission sources because of the land-sea breeze. When land-sea breeze is strengthen, the recirculation phenomena appears clearly. However particles aren't recirculated under weak synoptic condition. Also plume trajectory is analyzed and as a consequence, the smallest domain area have to be multiplied by 1.3 to understand recirculated dispersion pattern of particles.

• Journal of Environmental Science International
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• v.25 no.5
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• pp.683-694
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• 2016

Sensitivity analysis of the WRF model according to the impact of nudging (e.g., nudging techniques and application domains) was conducted during high nocturnal ozone episode to improve the prediction of the regional ozone concentration in the southeastern coastal area of the Korean peninsula. The analysis was performed by six simulation experiments: (1) without nudging (e.g., CNTL case), (2) with observation nudging (ONE case) to all domains (domain 1~4), (3) with grid nudging (GNE case) to all domains, (4)~(6) with grid nudging to domain 1, domain 1~2 and domain 1~3, respectively (GNE-1, GNE-2, GNE-3 case). The results for nudging techniques showed that the GNE case was in very good agreement with those observed during all analysis periods (e.g., daytime, nighttime, and total), as compared to the ONE case. In particular, the large effect of grid nudging on the near-surface meteorological factors (temperature, relative humidity, and wind fields) was predicted at the coastline and nearby sea during daytime. The results for application domains showed that the effects of nudging were distinguished between the meteorological factors and between the time periods. When applied grid nudging until subdomain, the improvement effects of temperature and relative humidity had differential tendencies. Temperature was increased for all time, but relative humidity was increased in daytime and was decreased in nighttime. Thus, GNE case showed better result than other cases.

• Journal of the Korean Geosynthetics Society
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• v.12 no.2
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• pp.1-11
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• 2013

Water content of subgrade soil in water supply systems has a large effect on performance. Many researchers lately make use of time-domain reflectometry (TDR) probes to measure the soil water content of subgrade soil from monitoring. The laboratory calibration test of TDR probe should be performed with soil field, because TDR probe can cause an error by type, gradation, density, and temperature of soil. This study shows the laboratory calibration test using TDR CS616, TDR-P3, TDR-T3. The calibration equations of TDR were then proposed. It was confirmed from the study that the data of TDR probe monitored in field could be used to estimate the freezing, unfrozen water content, and matric suction of soil.

• Structural Engineering and Mechanics
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• v.17 no.3_4
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• pp.445-466
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• 2004

In this paper, several modal identification techniques for output-only structural systems are extensively investigated. The methods considered are the power spectral method, the frequency domain decomposition method, the Ibrahim time domain method, the eigensystem realization algorithm, and the stochastic subspace identification method. Generally, the power spectral method is most widely used in practical area, however, the other methods may give better estimates particularly for the cases with closed modes and/or with large measurement noise. Example analyses were carried out on typical structural systems under three different loading cases, and the identification performances were examined throught the comparisons between the estimates by various methods.