• 한국수산과학회지
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• 제9권2호
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• pp.143-150
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• 1976

동일 년급군 체장에 관한 도수분포는 정규분포를 하는데, 어류자원의 감소계수를 z라 할 때 x 세 년급군의 미수가 $N_x=N_o\exp(-zx)$로 표시된다. 위의 두가지 사실에다 체장조성표를 이용하여 생잔율 $\varrho^{-z}$ 추정하는 방법을 연구한 결과를 요약하면 다음과 같다. 1. 연령, 분업에 관한 정밀조정표(표본)로부터 각년급군별 모체장평균, 모분산의 불편추정치($\bar{x},S^2$ 소표본일 때는 S^2 대신 $n/n-1{\cdot}S^2$를 구하였다. 2. 표본에서 구한 각 연금군별 모체장평균의 불편추정치$(\bar{x})$간의 경향선식과 각 년급군별 모분산($S^2$ 혹은 $n/n-1{\cdot}S^2$의 불편추정치간의 경향선식을 구하였다. 3. 각 경향선식에서 년급군별 모체장평균치와 모분산의 추정치$\hat{u},\hat{\sigma^2}$를 구하였다. 4. 각 년급군별로 모체장평균이 불편추정치$(\bar{x})$와 경향식에서 구한 모체장평균의 추정치$(\hat{u})$와의 차에 관한 유의성검정을 하고 또 각 년급군별로 모분산의 불편추정치($S^2$ 혹을 $n/n-1{\cdot}S^2$와 경향선식에서 구한 모분산의 추정치$\hat{\sigma}^2$와의 차에 관한 유의성검정을 하였다. 5. 유의성검정에서 두 종류 가운데 적어도 하나가 유의적이면 유의적인 년급군의 모체장평균(u)과 모분산$(\sigma^2)$을 모체장평균의 불편추정치$(\bar{x})$와 모분산의 불편추정치($S^2$ 혹은 $n/n-1{\cdot}S^2$로 한다. 2종의 검정이 유의적이 아닌 때는 해당하는 년급군의 모체장평균(u)과 모분산$\sigma^2$을 경향선식에서 구한 모체장평균의 추정치$\hat{u}$와 모분산의 추정치$(\hat\sigma^2)$로 하였다. 표본이 없는 년급군의 모체장평균(u)과 모분산$(\sigma^2)$도 역시 경향선식에서 구한 모체장평균 및 모분산의 추정치$\hat{u},\;\sigma^2$로 하였다. 6. 모체장평균(u)과 모분산$(\sigma^2)$이 추정되면 정규곡선면적표를 이용하여 년급군별로 각 체장계급에 해당하는 확률표를 만들었다. 7. 서로 이웃하는 체장계급의 비를 이용하여 생잔율 $\varrho^{-z}$ 값들을 구하였다. 8. $\varrho^{-z}$값들 중 이상적인 값은 유의적이면 기각하고 나머지 값으로 평균생잔율과 그 분산, 표준편차, 신뢰한계를 구하였다. 9. 향해 및 동지나해에 있어서 한국기선저인망에 어획된 참조기의 연령 및 체장에 관한 정밀조정표와 체장조직성표를 이용하여 년평균생잔율 $\varrho^{-z}$와 그 분산, 표준편차, 신뢰계수 $95\%$의 신뢰구분과 연평균 감소계수 Z를 구하였다.

• 한국전산구조공학회논문집
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• 제24권4호
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• pp.355-364
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• 2011

본 논문은 이미지 처리나 신호처리 및 정보압축 등에 사용되는 웨이블릿 급수를 이용하여 4계 타원형 미분방정식을 풀때 그 방법에 대하여 논의하고자 한다. 본 논문에서 사용한 Hat 웨이블릿 함수는 $H^1$-공간에 속한 급수로서 일반적으로 2계 타원형 미분방정식에 적용하기에는 무리가 없으나 4계 타원형 미분방정식에 적용하기에는 불충분한 미분가능회수를 가지고 있다. 따라서 이 문제를 극복하기 위해 모멘트와 처짐을 미지수로 하는 선형방정식을 순차적으로 구성하고 풀어내는 방법을 사용하였다. 모멘트와 처짐을 미지수로 하는 순차적 해석법은 탄성하중법(모멘트면적법)의 응용으로 생각할 수 있다. 또한 그 정식화과정에서 무요소법과 동일한 점과 차이점을 언급하였다. 예측한 바와 같이 Hat 웨이블릿 함수의 항을 많이 고려할수록 수치해석의 해가 향상되는 것을 확인할 수 있었다. 또한 응력특이를 갖는 오일러보 문제의 경우 제안된 해석법은 종래의 유한요소 해석값과도 비교되었다.

• Journal of the Korean Data and Information Science Society
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• 제14권2호
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• pp.303-311
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• 2003

We consider the problem of testing cell probabilities in sparse multinomial data. Aerts, et al.(2000) presented $T_1=\sum\limits_{i=1}^k(\hat{p}_i-p_i)^2$ as a test statistic with the local polynomial estimator $(\hat{p}_i$, and showed its asymptotic distribution. When there are cell probabilities with relatively much different sizes, the same contribution of the difference between the estimator and the hypothetical probability at each cell in their test statistic would not be proper to measure the total goodness-of-fit. We consider a Pearson type of goodness-of-fit test statistic, $T=\sum\limits_{i=1}^k(\hat{p}_i-p_i)^2/p_i$ instead, and show it follows an asymptotic normal distribution.

• 대한수학회지
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• 제52권1호
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• pp.1-21
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• 2015

C-domains are defined via class semigroups, and every C-domain is a Mori domain with nonzero conductor whose complete integral closure is a Krull domain with finite class group. In order to extend the concept of C-domains to rings with zero divisors, we study v-Marot rings as generalizations of ordinary Marot rings and investigate their theory of regular divisorial ideals. Based on this we establish a generalization of a result well-known for integral domains. Let R be a v-Marot Mori ring, $\hat{R}$ its complete integral closure, and suppose that the conductor f = (R : $\hat{R}$) is regular. If the residue class ring R/f and the class group C($\hat{R}$) are both finite, then R is a C-ring. Moreover, we study both v-Marot rings and C-rings under various ring extensions.

• Steel and Composite Structures
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• 제13권1호
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• pp.1-13
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• 2012

In this study, a new structural bracing system named 'Hat Knee Bracing' (HKB) is presented. In this structural system, a special form of diagonal braces, which is connected to the knee elements instead of beam-column joints, is investigated. The diagonal elements provide lateral stiffness during moderate earthquakes. However the knee elements, which is a fuse-like component, is designed to have one plastic joint in the knee elements for dissipation of the energy caused by strong earthquake. First, a suitable shape for brace and knee elements is proposed through elastic studying of the system and several practical parameters are established. Afterward, by developing applicable and highly accurate models in Drain-2DX, the inelastic behavior of the system is carefully considered. In addition, with inelastic study of the new bracing system and comparison with the prevalent Knee Bracing Frame system (KBF model) in nonlinear static and dynamic analysis, the seismic behavior of the new bracing system is reasonably evaluated.

• East Asian mathematical journal
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• 제24권1호
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• pp.81-95
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• 2008

Let E be a uniformly convex Banach space with a uniformly $G{\hat{a}}teaux$ differentiable norm, C a nonempty closed convex subset of E, and $T\;:\;C\;{\rightarrow}\;E$ a nonexpansive mapping satisfying the weak inwardness condition. Assume that every weakly compact convex subset of E has the fixed point property. For $f\;:\;C\;{\rightarrow}\;C$ a contraction and $t\;{\in}\;(0,\;1)$, let $x_t$ be a unique fixed point of a contraction $T_t\;:\;C\;{\rightarrow}\;E$, defined by $T_tx\;=\;tf(x)\;+\;(1\;-\;t)Tx$, $x\;{\in}\;C$. It is proved that if {$x_t$} is bounded, then $x_t$ converges to a fixed point of T, which is the unique solution of certain variational inequality. Moreover, the strong convergence of other implicit and explicit iterative schemes involving the sunny nonexpansive retraction is also given in a reflexive and strictly convex Banach space with a uniformly $G{\hat{a}}teaux$ differentiable norm.

• Journal of Magnetics
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• 제7권4호
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• pp.156-159
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• 2002

We have investigated the escape rate of nano-magnetic particle with a magnetic field applied along the easy axis. The model studied here is described by the Hamiltonian H=$K_1\hat{S}{_z^2}$ ＋ $K_2\hat{S}{_y^2}$ ＋ $g{\mu}_bB$ $\hat{S}_x(K_1>K_2>0)$ and the escape rate was calculated with in the semiclassical approximation. We have obtained a diagram for orders of the phase transition depending on the anisotropy constant and the external field. For $K_2$/$K_1>$0.85 the present model reveals the existence of the first order transition within the quantum regime.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.236.1-236.1
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• 2010

Due to global warming, the need to secure an alternative resource has become more important nationally. Due to the high tidal range of up to 9.7m on the west coast of Korea, numerous tidal current projects are being planned and constructed. The rotor, which initially converts the energy, is a very important component because it affects the efficiency of the entire system, and its performance is determined by various design variables. In this paper, a design guideline of current generating HAT rotor and acceptable field rotor in offshore environment is proposed. To design HAT rotor model, wind mill rotor design principles and turbine theories were applied based on a field HAT rotor experimental data. To verify the compatibility of the rotor design method and to analyze the properties of design factors, 3D CFD model was designed and analysed by ANSYS CFX. The analysis results and findings are summarized in the paper.

• International Journal of Reliability and Applications
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• 제7권2호
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• pp.177-186
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• 2006

Typical confidence intervals for a mean or mean residual life (MRL) are centered about the mean or mean residual life. We discuss novel confidence intervals that produce statements like "we are 95% confident that the MRL function, e(t), is greater than a prespecified $\mu_o$ for all t in the interval [0, $\hat{\theta})$)" where $\hat{\theta}$ is determined from the sample data, confidence level, and $\mu_o$. Also, we can have statements like 'we are 95% confident that the MRL of population 1, namely $e_1$(t), is greater than the MRL of population 2, $e_2$(t), for all t in the interval [0, $\hat{\theta}$)" where $\hat{\theta}$ is determined from the sample data and confidence level. We illustrate these one and two sample confidence intervals on internal bonds (tensile strengths) for an important modem engineered wood product, called medium density fiberboard (MDF), used internationally.

• 한국신뢰성학회지:신뢰성응용연구
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• 제3권2호
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• pp.127-136
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• 2003

This paper investigates the effect of individual observations in regression models with MA(1) errors through the 'hat matrix' It shows that the first observation has the largest hat matrix diagonal component for $\theta$＜0 in the regression model with an intercept. This provides additional evidence for retaining the first observation in performing estimation in this setting. When the regression model goes to the origin and the independent variable has a deterministic trend, the last observation has the greatest leverage for │$\theta$│＜1 and may have potentially large impact on parameter estimation.