• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.229-229
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• 2015

Downscaling is a fundamental procedure in the assessment of the future climate change impact at regional and watershed scales. Hence, it is important to investigate the spatial variability of the climate conditions that are constructed by various downscaling methods in order to assess whether each method can model the climate conditions at various spatial scales properly. This study introduces a fundamental research from Jang and Kavvas(2015) that precipitation variability from a popular statistical downscaling method (BCSD) and a dynamical downscaling method (MM5) that is based on the NCAR/NCEP reanalysis data for a historical period and on the CCSM3 GCM A1B emission scenario simulations for a projection period, is investigated by means of some spatial characteristics: a) the normalized standard deviation (NSD), and b) the precipitation change over Northern California region. From the results of this study it is found that the BCSD method has limitations in projecting future precipitation values since the BCSD-projected precipitation, being based on the interpolated change factors from GCM projected precipitation, does not consider the interactions between GCM outputs and local geomorphological characteristics such as orographic effects and land use/cover patterns. As such, it is not clear whether the popular BCSD method is suitable for the assessment of the impact of future climate change at regional, watershed and local scales as the future climate will evolve in time and space as a nonlinear system with land-atmosphere feedbacks. However, it is noted that in this study only the BCSD procedure for the statistical downscaling method has been investigated, and the results by other statistical downscaling methods might be different.

• Journal of Ocean Engineering and Technology
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• v.23 no.2
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• pp.47-52
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• 2009

A Lagrangian particle tracking model coupled with the Princeton Ocean Model were used to estimate the average residence time of coastal water in Masan Bay, Korea. Our interest in quantifying the transport time scales in Masan Bay was stimulated by the search for a mechanistic understanding of this spatial variability, which is consistent with the concept of spatially variable transport time scales. Tidal simulation was calibrated through a comparison with the results of semi-diurnal current and water elevation measured at the tidal stations of Masan, Gadeokdo. In the model simulations, particles were released in eight cases, including slack before ebb, peak ebb, slack before flood, and peak flood, during both spring and neap tides. The averaged values obtained from the particle release simulations were used for the average residence times of the coastal water in Masan Bay. The average residence times for the southeastern parts of Somodo and the Samho River, Masan Bay were estimated to be about 20~50days and 70~80days, respectively. The spatial difference for the average residence time was controlled by the tidal currents and distance from the mouth of the bay. Our results might provide useful for understanding the transport and behavior of coastal water in a bay and might be used to estimate the dissimilative capacity for environmental assessment.

• Korean Journal of Ichthyology
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• v.24 no.4
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• pp.297-301
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• 2012

Three specimens of Moolgarda seheli were collected for the first time from the southern coastal waters of Jeju Island in October 2010. This species is characterized by scales with a flexible membranous edge, a distinctive dark dot on the upper axis of the pectoral fin base, 39 lateral line scales, and 24~25 vertebrae. The newly proposed Korean name of the genus Moolgarda is "Cho-seung-kkori-sung-eo-sok" and that of M. seheli is "Cho-seung-kko-ri-sung-eo".

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.73.2-73.2
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• 2014

We investigate the rotation measure (RM) of the nearby low luminosity AGN M87 by using archival polarimetric VLA data at 8, 15, 22 and 43 GHz. For the first time, the RM properties of its jet are resolved at at arc-second scales. The distribution of the RM appears to be a gaussian with a mean value of ~200rad/m2 and the power spectrum follows a power law with index -2.5. A simple Kolmogorov model assuming a random turbulent magnetic fields extrinsic to the jet appears not to be adequate to explain the observed RM power spectra. On the other hand, underlying RM gradients possibly connected with the jet could be a possible interpretation.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1269-1272
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• 2005

We propose a simple and efficient driving algorithm to reduce Dynamic False Contour(DFC) in Plasma Display Panels(PDPs) by using both accumulation and combination of light emission periods. Although the accumulative way of light emission in sustain period is regarded as more effective than combinational way to reduce DFC, it takes much addressing time to express high gray-scale. Therefore, we combine accumulative and combinational light emission methods to reduce DFC. In the proposed method, one TV field (16.7ms) is composed of four combinational subfields for expressing small gray scales and fifteen accumulative subfields for large gray scales. In addition, we use some Graphic Signal Processing(GSP) algorithm to get more natural images by reducing DFC.

• Smart Structures and Systems
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• v.26 no.2
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• pp.185-193
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• 2020

Nonlinear vibration of sandwich plate with functionally graded material (FGM) core and carbon nano tubes reinforced (CNTs) nano-composite layers by considering temperature-dependent material properties are studied in this paper. Base on Classical plate theory (CPT), the governing partial differential equations of motion for sandwich plate are derived using Hamilton principle. The Galerkin procedure and multiple scales perturbation method are used to find relation between nonlinear frequency and amplitude of vibration response. The dynamic responses of the sandwich plate are also investigated in both time and frequency domains. Then, the effects of nonlinearity, excitation, power law index of FG core, volume fraction of carbon nanotube, the function of material variations of FG core, temperature changes, scale transformation parameter and damping factor on the frequency responses are investigated.

• ETRI Journal
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• v.31 no.2
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• pp.121-128
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• 2009

In this paper, we describe a fixed-threshold sequential minimal optimization (FSMO) for structured SVM problems. FSMO is conceptually simple, easy to implement, and faster than the standard support vector machine (SVM) training algorithms for structured SVM problems. Because FSMO uses the fact that the formulation of structured SVM has no bias (that is, the threshold b is fixed at zero), FSMO breaks down the quadratic programming (QP) problems of structured SVM into a series of smallest QP problems, each involving only one variable. By involving only one variable, FSMO is advantageous in that each QP sub-problem does not need subset selection. For the various test sets, FSMO is as accurate as an existing structured SVM implementation (SVM-Struct) but is much faster on large data sets. The training time of FSMO empirically scales between O(n) and O($n^{1.2}$), while SVM-Struct scales between O($n^{1.5}$) and O($n^{1.8}$).

• Journal of Surface Science and Engineering
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• v.33 no.5
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• pp.365-372
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• 2000

Pure $Fe_3$Al alloys with three different compositions of Fe-21.8%Al, Fe-24.1%Al and Fe-27.2%Al were prepared by vacuum induction melting followed by homogenization and hot forging. The long-time oxidation behavior of the prepared alloys was studied at 1073, 1273 and 1473k in air. The oxidation resistance greatly increased with an increase in Al contents. Thin and uniform oxide scales were always formed on Fe-27.2%Al, while thick and fragile oxide scales were formed on Fe-(21.8, 24.1%)Al. Internal oxidation was observed in Fe-(21.8, 24.1%)Al, when oxidized above 1273K. The major oxidation product of all the oxidized alloys was always $\alpha$-$Al_2$$O_3$.

• Earthquakes and Structures
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• v.22 no.5
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• pp.517-526
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• 2022

In this paper, nonlinear P-delta effects are studied on the seismic performance, and the modal responses of a flexural frame, considering large deformations. Using multiple scales method, the nonlinear differential equations of motion are estimated, and the nonlinear interactions between the frame's degrees of freedom are outcropped. The results of time and frequency domain analyzes of a dynamic model are examined under internal resonance cases, and the linear and nonlinear responses are investigated in each modal cases. Also, changing the modal responses with respect to the amplitude and frequency of the harmonic forces is evaluated. It is shown that the dominant absorption of energy is in the first natural frequency of the frame, in the case of earthquake excitation, and when a harmonic force is applied to the frame, the peaks of the frequency domain responses depending on the frequency of harmonic force are in the first, and second or third natural frequency of the structure.

• Journal of Family Resource Management and Policy Review
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• v.19 no.4
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• pp.141-161
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• 2015

The purpose of this study was to explore the differences in time perspective by socio-demographic variables and to investigate the effect of time perspective on time management and life satisfaction for college students. Questionnaires including time perspective, time management, and life satisfaction scales were used for this study. The survey data from 382 college students were analyzed by frequency, percentage, mean, standard deviation, t-test, ANOVA, Duncan test, Pearson's correlation analysis, and stepwise regression. The time perspective, composed of four factors future insensibility and present, past, and future orientation, differed according to the sex, academic grade, and specialty of the college students. The time perspective of the college students and the socioeconomic status of their households were investigated as effective variables on time management and life satisfaction. Based on these results, the implications for research and policy on the time perspective of college students were discussed.