• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.53.3-53.3
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• 2017

While quasars are sparse in number density, they reside at relatively high-redshift as compared to galaxies. Hence, they are likely to be less non-linearly evolved than the galaxy population, and thus have a distribution that more closely mirrors the primordial density field. Therefore, they offer an intriguing opportunity to search for primordial non-Gaussianity (PNG). To this end, the 3-point correlation function (3PCF) is an excellent statistical tool to detect departures from Gaussianity, vanishing for a Gaussian field. In this work, we will make the first-ever measurement of the large-scale quasar 3PCF from the SDSS-IV DR14 quasar sample (spanning the largest volume to-date) to place constraints on PNG through the usual f_NL-type parametrization. This work will use the order N^2-time 3PCF algorithm of Slepian & Eisenstein (2015), with N the number of objects.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.3
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• pp.335-342
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• 1988

In this paper, we proposed a new algorithm for EMG low frequency analysis. Through the power spectrum analysis of Gaussian's, Gamma's and Erlang's PDF(probability density function) based on the proposed algorithm, the proper PDF of IPI (inter pulse interval) representing the firing rate of muscle was suggested. In order to verify the proposed algorithm EMG signals of masseter and biceps muscle were detected by surface electrode and its power spectrum analysis was performed. The experimental results are compared with the computer simulaiton. As a result, the masseter muscle's IPI was fitted by Gamma PDF, having a 10Hz fundamental frequency including n(1+\ulcornerfp high harmnic frequency on 10% MVC(maximum voluntary contaraction). And the biceps muscle's IPI was fitted by Gaussian PDF, also it have a 14Hz fundamental frequency.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.4
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• pp.1-5
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• 1976

Spectrum의 시간기복을 나타내는 시간 및 주파수의 함수 F(w,t,T) 및 W(w,t,T)를 정의하였고, 실례에 적용시켰다. Fourier변환을 f(t)와 Phasor ejwt와의 Correlation으로 정의하였고 그 변환시분이 시간마다의 성분의 합계이어서 t 시각에서의 Spectrum을 그 근거에서의 f(t)값에만 의함을 증명하였다. Two new time functions defining Time Dependent Fourier Transform F(w,t,T) and Time Dependent Spectrum Density W(w,t,T) are deduced. courier transform is defined as the correlation between the time function f(t) and phasor ejwt. Several theorems corncerning the new functions are proved in order to verify the instantaneous cause a effet of the function f(t) and the nuctuating spectrum.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.246-249
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• 2009

Due to the additive white Gaussian noise (AWGN), images are often corrupted. In recent days, Bayesian estimation techniques to recover noisy images in the wavelet domain have been studied. The probability density function (PDF) of an image in wavelet domain can be described using highly-sharp head and long-tailed shapes. If a priori probability density function having the above properties would be applied well adaptively, better results could be obtained. There were some frequently proposed PDFs such as Gaussian, Laplace distributions, and so on. These functions model the wavelet coefficients satisfactorily and have its own of characteristics. In this paper, mixture distributions of Gaussian and Laplace distribution are proposed, which attempt to corporate these distributions' merits. Such mixture model will be used to remove the noise in images by adopting Maximum a Posteriori (MAP) estimation method. With respect to visual quality, numerical performance and computational complexity, the proposed technique gained better results.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.7 s.238
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• pp.846-853
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• 2005

In this paper, mass transfer in turbulent flow around a rotating circular cylinder is investigated by Direct Numerical Simulation for Schmidt numbers Sc=1 and 1670. Correlation between Sherwood and Reynolds number predicted agrees well with other experimental results over both Sc. Reynolds analogy identified at Sc=1 definitely causes a strong correlation between concentration fluctuation and streamwise velocity. For Sc=1670, it is found that positive small values of concentration fluctuations are observed more frequently than the case of Sc=1 particularly out of the range of Nernst diffusion layer in the viscous sub-layer. This fact is fully confirmed by detailed statistical study using a probability density function of concentration fluctuations.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.30-33
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• 2002

We have shown that it is possible to form a fibrilar network of fibronectin on a polyelectrolyte polymer film whose dimensions are similar to those reported on the extra cellular matrix. The fibronectin network was observed to form only when the charge density of the polymer was in excess of the natural charge density of the cell wall. Furthermore, the self-organized fibronectin layer was much thicker than the polymer film, indicating that long ranged interaction may playa key role in the assembly process. It is therefore important to understand the structure of the polymer layer/protein interface. Here we report on a neutron reflectivity study where we explore the structure of the polyelectrolyte layer, in this case sulfonated polystyrene (PSSx,), with varying degree of sulfonation (x<30%), as a function of sulfur content and counter ion concentration. These results are then correlated with systemic study of the adsorption and the multilayer formation of fibronectin as a function of incubation time for various sulfonation levels of $PSSx.^1$

• Journal of Information Display
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• v.10 no.4
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• pp.158-163
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• 2009

There are two kinds of well-known electron emissions from metal: field and thermionic emission. For thermionic emission, electrons come out of a metal due to the thermal energy, whereas for field emission, electrons tunnel out of a metal through the strong electric field. In this study, the most general electron emission caused by the temperature and electric field with a free electron gas model was considered. The total current density of electron emission comes from the field emission effect, where the electron energy is lower than vacuum, and from the thermionic-emission effect, where the electron energy is higher than vacuum. The total current density of electron emission is shown as a function of the temperature for a constant electric field, and as a function of the electric field for a constant temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.112-116
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• 2001

Organic Electroluminescence device, which have the single-layer structure of ITO(indium-tin-oxide)/MEH-PPV (Poly[2-(2'-ethylhexyloxy )-5-methoxy-1,4-pheny lenevinylene])/Al(aluminium) and ITO/MEH-PPV/$Alq_3$(tris-8-hydroxyquinolinato aluminium)/Al were fabricated and electrical properties were investigated. Experimental results, in single-layer structure, shown that turn on voltage is about 12 V, and current density increases as a function of increasing temperature. It was explained by thermionic emission. In double-layer structure, thickness $200\AA$ of $Alq_3$ is shown electrical properties that turn on voltage is about 11 V, and current density decreases as a function of increasing temperature.ࠀȀ 耀Ѐ€

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.3
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• pp.215-220
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• 2002

This paper proposes a method to apply the Backpropagation(BP) algorithm of MVL(Multi-Valued Logic) Neural Network to pattern recognition. It extracts the property of an object density about an original pattern necessary for pattern processing and makes the property of the object density mapped to MVL. In addition, because it team the pattern by using multiple valued logic, it can reduce time f3r pattern and space fer memory to a minimum. There is, however, a demerit that existed MVL cannot adapt the change of circumstance. Through changing input into MVL function, not direct input of an existed Multiple pattern, and making it each variable loam by neural network after calculating each variable into liter function. Error has been reduced and convergence speed has become fast.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.11 s.242
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• pp.1248-1256
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• 2005

This study was undertaken to investigate the flow characteristics of emulsified fuel with the ultrasonic energy-adding system by using the chaotic method. Efffcts of water contents within emulsified fuel, flow rate and tube length with 5m in diameter from an emulsified chamber has been discussed on the strange attractor and power spectral density function. Five probe sensors were set up from 0.5 to 2.5m by length in 0.5m increments in the tube. In particular, the chaotic features of this system have been practically characterized in terms of chaotic statistics such as the power spectral density function and phase space portraits by resorting to the somewhat noble deterministic chaos theory. In the tube, the dominant frequency increased with increasing water contents and flow rate, but decreased a little with an increase in the length from the emulsified chamber.