• 한국측량학회지
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• 제30권6_2호
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• pp.653-663
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• 2012

Using soft classification, it is possible to obtain the land cover proportions from the remotely sensed image. These land cover proportions are then used as input data for a procedure called "super-resolution mapping" to produce the predicted hard land cover layers at higher resolution than the original remotely sensed image. Superresolution mapping can be implemented using a number of algorithms in which the Hopfield Neural Network (HNN) has showed some advantages. The HNN has improved the land cover classification through superresolution mapping greatly with the high resolution data. However, the super-resolution mapping is based on the spatial dependence assumption, therefore it is predicted that the accuracy of resulted land cover classes depends on the relative size of spatial features and the spatial resolution of the remotely sensed image. This research is to evaluate the capability of HNN to implement the super-resolution mapping for SPOT image to create higher resolution land cover classes with different zoom factor.

• Bulletin of the Korean Chemical Society
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• 제19권11호
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• pp.1194-1198
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• 1998

The density and the viscosity of aqueous PEO solutions are observed with the several concentrations of PEO at 20 ℃. The effects of urea on them are also observed. The apparent and the partial specific volumes of PEO are calculated from the density data, which result that the polymer-polymer interaction is dominating in the binary aqueous PEO solutions, while the polymer-solvent interaction is dominating in the ternary aqueous urea-PEO solutions. It is explained by the urea induced breakage of the structured water originated from the hydrophobic interactions and the binding of the urea to the PEO chain. The concentration dependence of relative viscosity and the density dependence of fluidity is also discussed with the concept of the polymersolvent and the polymer-polymer interactions of aqueous urea-PEO solutions.

• 국제초고층학회논문집
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• 제8권4호
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• pp.313-324
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• 2019

This paper presents the analysis of wind speeds data measured on top of three neighboring high-rise buildings close to a beach in Xiamen city, China, during Typhoon "Usagi" 2013. Wind tunnel simulation was carried out to validate the field measurement results. Turbulence intensity, turbulence integral scale, power spectrum and cross correlation of recorded wind speed were studied in details. The low frequency trend component of the typhoon speed was also discussed. The field measurement results show turbulence intensity has strong dependence to the wind speed, upwind terrain and even the relative location to the Typhoon center. The low frequency fluctuation could severely affect the characteristics of wind. Cross correlation of the measured wind speeds on different buildings also showed some dependence on the upwind terrain roughness. After typhoon made landfall, the spatial correlation of wind speeds became weak with the coherence attenuating quickly in frequency domain.

• ETRI Journal
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• 제44권3호
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• pp.504-511
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• 2022

Monte Carlo simulations show that, as temperature increases, the average kinetic energy of channel electrons in a GaN transistor first decreases and then increases. According to the calculations, the relative energy change reaches 40%. This change leads to a reduced barrier height due to quantum coupling among the three-dimensional motions of channel electrons. Thus, an analysis and physical model of the gate leakage current that includes drift velocity is proposed. Numerical calculations show that the negative and positive temperature dependence of gate leakage currents decreases across the barrier as the field increases. They also demonstrate that source-drain voltage can have an effect of 1 to 2 orders of magnitude on the gate leakage current. The proposed model agrees well with the experimental results.

• 대한기계학회논문집B
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• 제39권8호
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• pp.677-682
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• 2015

격자 볼츠만 기법(Lattice Boltzmann method)을 사용하여 에멀전의 유변학적 특성을 파악하기 위한 시뮬레이션을 수행하였다. 간단한 전단 유동하에서 온도와 전단속도, 계면장력에 변화를 주어 에멀전(decane-in-water)의 상대점도를 계산하고 이를 분석하였다. 에멀전의 상대점도는 온도가 증가함에 따라 감소하였고, 전단속도가 증가함에 따라 감소하는 전단박하(Shear thinning) 현상을 보여주었다. 이는 크로스 모델(Cross model)을 통해 검증하였고 일치하는 경향을 보여주었다. 계면에 존재하는 계면활성제(Surfactant)를 통해 제어되는 계면장력이 증가할수록 상대점도는 감소하는 경향을 보여주었다. 이것은 큰 계면장력에서는 기름방울의 변형이 억제되고 점도가 상대적으로 높은 기름방울의 표면적이 감소하면서 나타난다고 해석할 수 있다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.348-351
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• 2009

In order to evaluate the performance of a grounding system against lightning or fault currents including high frequency components, the grounding impedance should be considered rather than its ground resistance. Recently, some researches on the evaluation and modeling of the grounding impedances have been carried out but the results have not been yet sufficient. This paper deals with the frequency dependence of the resistivity and relative dielectric constant of sand associated with water contents. As a result, the resistivity of sand is getting lower with increasing water content and it is nearly independent on the frequency in the range of less than 1MHz, and is decreased over the frequency range of above 1MHz. Also, the relative dielectric constant is rapidly decreased with the frequency in the range of less than 10kHz, but it is nearly not dependent on the frequency over the frequency range of 10kHz. It was found from this work that the frequency dependance of resistivity and relative dielectric constant of soil should be considered in designing the grounding systems for protection against lightning or surges.

• 생물정신의학
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• 제4권1호
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• pp.108-115
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• 1997

The alcoholic neuropathies developed in approximately 34% of chronic alcoholics and the sexual dysfunction had been experienced in 8-54% of male alcoholics(Schiavi 1990). The aims of this study were to identify the prevalence of subclinical polyneuropathies and sexual disorders in alcohol dependence, and to evaluate the association between them. The nerve conduction velocity(NCV), electromyography(EMG), and pudendal somatosensory evoked potentials(SEPs) were tested for the male alcoholics(N=34) and controls(N=17 for NCV & EMG, N=25 for pudendal SEPs). The pudendal SEPs were measured by the following procedures, in which we stimulated the dorsal nerve of penis attached by the ring electrode(stimulus intensity, three times of threshold : stimulus rate, 1-4.7Hz : stimulus duration, 0.1 or 0.2msec), and recorded at the scalp(active electrode, 2cm behind Cz : reference electrode, Fz). The NCV and EMG detected signs of peripheral neuropathies in 79.4% of alcoholics. Among the alcoholics, 64.7% were abnormal on the pudendal SEPs. Among the alcoholics who revealed abnormality on EMG and NCV, 81.4% were abnormal on the pudendal SEPs, in which 51.9% were not responded. The P1 latencies of pudendal SEPs on neuropathic alcoholics were significantly delayed(p<0.05) than non-neuropathic alcoholics. There was a relative correlation between peripheral neuropathies and sexual disorders in the alcoholics. The prevalence of subclinical neuropathies and sexual disorders seemed to be much higher in alcohol dependence than expectation, and these two problems were relatively correlated, and our results suggested that the peripheral polyneuropathies were one of the prerequisites of sexual disorders.

• ETRI Journal
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• 제23권1호
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• pp.33-38
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• 2001

A numerical simulation and an experimental implementation of T-shaped microstrip-fed printed slot array antenna are presented in this paper. The proposed antenna with relative permittivity 4.3 and thickness 1.0mm is analyzed by the finite-difference time-domain (FDTD) method. The dependence of design parameters on the bandwidth characteristics is investigated. The measured bandwidth of twin-slot array antenna is from 1.37 GHz to 2.388 GHz, which is approximately 53.9 % for return loss less than or equal to -10 dB. The bandwidth of twin-slot is about 1.06 % larger than that of single-slot antenna. The measured results are in good agreement with the FDTD results.

• 호남수학학술지
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• 제29권4호
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• pp.653-666
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• 2007

Let R be a commutative Noetherian ring (with a nonzero identity) and let M be an R-module. Further let I be an ideal of R. In this paper, by putting a suitable condition on $Ass_R$(M), we obtain some results concerning $I^{*(M)}$ and prove that the sequence of sets $Ass_R(R/(I^n)^{*(M)})$, $n\;\in\;N$, is increasing and ultimately constant. (Here $(I^n)^{*(M)}$ denotes the integral closure of $I^n$ relative to M.)

• 한국통신학회논문지
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• 제16권7호
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• pp.615-627
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• 1991

In this paper the relative magnitudes of the 1/f noise constants were experimentally investigated in the plana type's resistors fabricated with the different type's semicondector materials, and a new measurement technique for the 1/f noise in the semiconductor plana type's resistors may be located at the semiconductor and silicon dioxde.