• 물과 미래
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• 제28권5호
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• pp.117-127
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• 1995

해상도를 고려하는 GIUH 모형에 대한 적용과 분석을 평창강 유역의 소유역인 이목정유역에 대하여 수행하였다. 모형의 적용과 Fractal 분석을 위해 1:25,000, 1:50,000 그리고 1:100,000 축척의 지도를 이용하였다. 따라서 축척간의 비율이 일정한 값을 갖는다. 링크의 길이는 해상도 1mm의 구장기를 이용하였고 Fractal 차원은 Richardson 방법을 사용하였다. 지도의 축척에 따라 매개변수들의 현저한 변화를 발견하였으며 이러한 경향은 매개변수의 물리적 의미를 상실하게 한다. 그런데 Fractal 변환과 의 Melton지형법칙은 이러한 규모문제를 효과적으로 조정해주는 역할을 할 수 있다. 그리고 이 방법은 하도망과 유역간의 연관성을 모형에 반영할 수 있는 장점이 있다. 이 연구에서 제안한 GIUH의 적용성을 검증하기 위해 지수형 GIUH 모형과 비교하였다. 그 결과 제안된 2모수 gamma GIUH 모형이 좋은 재현성을 보였다. 따라서 Fractal 이론을 도입한 2모수 gamma GIUH 모형은 축척을 고려하는 IUH를 유도하는데 있어서 적절하다고 할 수 있다.

• 항공우주기술
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• 제7권2호
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• pp.31-37
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• 2008

항공기의 변수 추정을 위해서는 비행시험을 통해 얻어진 데이터를 이용해야한다. 비행 시험의 문제점으로 비행중에는 데이터를 재조정하기가 힘들다. 이러한 점을 감안하여 본 논문에서는 변수추정을 위한 비행시험을 대신해서 선회 비행 데이터를 사용하여 주파수영역에서 변수를 추정하는 상용화된 변수추정프로그램(CIFER)으로 스마트 무인기 40% 축소기의 동적 파라미터를 추정하였다.

• 응용통계연구
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• 제22권4호
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• pp.879-891
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• 2009

We developed the projected l-axial skew-normal(LASN) family of distributions for I-axial data. The LASN family of distributions contains the semicircular skew-normal(SCSN) and the circular skew-normal(CSN) families of distributions as special cases. The LASN densities are similar to the wrapped skew-normal densities for the small values of the scale parameter. However CSN densities have more heavy tails than those of the wrapped skew-normal densities on the circle. Furthermore the CSN densities have two modes as the scale parameter increases. The LASN distribution has very convenient mathematical features. We extend the LASN family of distributions to a bivariate case.

• 대한전자공학회논문지
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• 제26권10호
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• pp.1554-1560
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• 1989

This paper suggests the algorihtm which extracts the classification parameter relative to the only feature of document patterns even though they are rotated or scaled, and also classifies them. With the complex logarithmic conformal mapping, the sample of the document pattern image makes the pattern image of the complex logarithmic plane. Because the power spectrum of this plane is invariant to the rotation, and scale of the pattern image, it is used as the characteristics parameter of the patten image. By using the coherence function, this method analyzes the standard and input power spectrum. additionally, it classifies the input pattern image. Even though input image is rotated, our algorithm can classify it without reference to the rotation, and this is possible when the scale is in the range of 0.5-1.5.

• International Journal of Fluid Machinery and Systems
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• 제10권3호
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• pp.197-208
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• 2017

When Francis turbines operate at partial load, residual swirl in the draft tube causes low-frequency pulsation of pressure and power output. Scale effects and system response may bias the prediction of prototype behavior based on laboratory tests, but could be overcome by means of a 1D analytical model. This paper deals with the two most important features of such a model, the compliance and the source of excitation. In a distributed-parameter version, compliance should be represented as an exponential function of local pressure. Lack of similarity due to different Froude number can thus be compensated. The normally unknown gas content in the vortex cavity has significant influence on the pulsation, and should therefore be measured and considered as a test parameter.

• Communications for Statistical Applications and Methods
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• 제4권3호
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• pp.929-941
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• 1997

In this paper, we propose the minimum risk estimator (MRE) and the approximate maximum likelihood estimator (AMLE) of the location and the scale parameters of the two-parameter exponential distribution with Type-II censoring. The MRE's can be derived by minimizing the mean squared error among the class of estimators which include some estimators as special cases. We show that the MRE's are more efficient than the other estimators of the scale and the location parameter in the terms of the mean squared error.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.183-195
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• 2014

Kinetically constrained models (KCM) have attracted interest as models that assign dynamic origins to the interesting dynamic properties of supercooled liquid. Signs of dynamic heterogeneity in the crossover model that linearly interpolates between the FA-like symmetric constraint and the East model constraint by asymmetric parameter b were investigated using Monte Carlo technique. When the asymmetry parameter was decreased sufficiently, smooth fragile-to-strong dynamic transition was observed in terms of the relaxation time, diffusion constant, Stokes-Einstein violation, and dynamic length scale. Competition between energetically favored symmetric relaxation mechanism and entropically favored asymmetric relaxation mechanism is behind such transition.

• Journal of the Korean Data and Information Science Society
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• 제15권1호
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• pp.227-237
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• 2004

In this paper we presented a Bayesian inference approach for estimating the location and scale parameters of the lognormal distribution using iterative Gibbs sampling algorithm. We also presented estimation of location parameter by two non iterative methods, importance sampling and weighted bootstrap assuming scale parameter as known. The estimates by non iterative techniques do not depend on the specification of hyper parameters which is optimal from the Bayesian point of view. The estimates obtained by more sophisticated Gibbs sampler vary slightly with the choices of hyper parameters. The objective of this paper is to illustrate these tools in a simpler setup which may be essential in more complicated situations.

• Smart Structures and Systems
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• 제17권2호
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• pp.257-274
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• 2016

The nonlocal static bending, buckling, free and forced vibrations of graphene nanosheets are examined based on the Kirchhoff plate theory and Taylor expansion approach. The nonlocal nanoplate model incorporates the length scale parameter which can capture the small scale effect. The governing equations are derived using Hamilton's principle and the Navier-type solution is developed for simply-supported graphene nanosheets. The analytical results are proposed for deflection, natural frequency, amplitude of forced vibration and buckling load. Moreover, the effects of nonlocal parameter, half wave number and three-dimensional sizes on the static, dynamic and stability responses of the graphene nanosheets are discussed. Some illustrative examples are also addressed to verify the present model, methodology and solution. The results show that the new nanoplate model produces larger deflection, smaller circular frequencies, amplitude and buckling load compared with the classical model.

• Computers and Concrete
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• 제24권6호
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• pp.499-511
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• 2019

In this paper, wave propagation of double-bonded Cooper-Naghdi micro sandwich cylindrical shells with porous core and carbon nanotube reinforced composite (CNTRC) face sheets are investigated subjected to multi-physical loadings with temperature dependent material properties. The governing equations of motion are derived by Hamilton's principle. Then, the influences of various parameters such as wave number, CNT volume fraction, temperature change, Skempton coefficient, material length scale parameter, porosity coefficient on the phase velocity of double-bonded micro sandwich shell are taken into account. It is seen that by increasing of Skempton coefficient, the phase velocity decreases for higher wave number and the results become approximately the constant. Also, by increasing of the material length scale parameter, the cut of frequency increases, because the stiffness of micro structure increases. The obtained results for this article can be used to detect, locate and quantify crack.