• Korean Journal of Mathematics
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• 제29권4호
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• pp.665-677
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• 2021

The main object of this study is to introduce the spaces $c_0({\hat{F}^q)$ and $c({\hat{F}^q)$ derived by the matrix ${\hat{F}^q$ which is the multiplication of Riesz matrix and Fibonacci matrix. Moreover, we find the 𝛼-, 𝛽-, 𝛾- duals of these spaces and give the characterization of matrix classes (${\Lambda}({\hat{F}^q)$, Ω) and (Ω, ${\Lambda}({\hat{F}^q)$) for 𝚲 ∈ {c₀, c} and Ω ∈ {ℓ₁, c₀, c, ℓ_∞}.

• Kyungpook Mathematical Journal
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• 제55권2호
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• pp.355-372
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• 2015

In the present paper, by using the Fibonacci difference matrix, we introduce the almost convergent sequence space $\hat{c}^f$. Also, we show that the spaces $\hat{c}^f$and $\hat{c}$ are linearly isomorphic. Further, we determine the ${\beta}$-dual of the space $\hat{c}^f$ and characterize some matrix classses on this space. Finally, Fibonacci core of a complex-valued sequence has been introduced, and we prove some inclusion theorems related to this new type of core.

• 품질경영학회지
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• 제17권1호
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• pp.107-115
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• 1989

This study is suggested tn find a methodology of influential subset detecting by using diagonal elements of the hat matrix, $h_{ij}$, and off-diagonal elements of the modified hat matrix, $h_{ij^*}$. And this study shows that elements of two matrix is very useful to detect a masking subset in various situations by analytic and emperical explanations. Also a desirable procedure to detect the significant subset and the calibration points for $h_{ij}$ and $h_{ij^*}$ are recommended.

• Journal of the Korean Statistical Society
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• 제7권2호
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• pp.101-104
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• 1978

This paper considers the problem of estimating $\hat{\beta}$ in the case errors occur in observing the values of q-variables $X_1, X_2, ..., X_q$. The approximated estimator $\hat{\beta}(e)$ is obtained and its expected value, bias and covariance matrix are studied.

• 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.

• Journal of applied mathematics & informatics
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• 제39권5_6호
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• pp.895-918
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• 2021

Human African Trypanosomiasis (HAT) also known as sleeping sickness, is a neglected tropical vector borne disease caused by trypanosome protozoa transmitted by bites of infected tsetse fly. The basic reproduction number, R₀ derived using the next generation matrix method which shows that the disease persists in the population if the value of R₀ > 1. The numerical simulations of optimal control model carried out to determine the control strategy that can combat HAT under the minimum cost. The results indicate that, the use of both education campaign, treatment and insecticides are more efficient and effective to eliminate HAT in African community but too costly. Furthermore, the cost-effectiveness of the control measures (education campaign, treatment and insecticides) were determined using incremental cost-effectiveness ratio (ICER) approach and the results show that, the use of education and treatment of infected people as the best cost effective strategy compared to other strategies.

• Journal of applied mathematics & informatics
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• 제30권5_6호
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• pp.993-1003
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• 2012

The family of graphs $\hat{W}_{4n}$ is defined by taking the simple whee graph $W_{n+1}$ with $n$ rim vertices and then adding three extra vertices on every rim edge of the wheel. In this paper, the critical group of this whole family of graphs is investigated.

• Journal of the Korean Data and Information Science Society
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• 제26권6호
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• pp.1557-1563
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• 2015

Multiclass classification is typically performed using the voting scheme method based on combining binary classifications. In this paper we propose multiclass classification method for large data, which can be regarded as the revised one-vs-all method. The multiclass classification is performed by using the hat matrix of least squares support vector machine (LS-SVM) ensemble, which is obtained by aggregating individual LS-SVM trained on each subset of whole large data. The cross validation function is defined to select the optimal values of hyperparameters which affect the performance of multiclass LS-SVM proposed. We obtain the generalized cross validation function to reduce computational burden of cross validation function. Experimental results are then presented which indicate the performance of the proposed method.

• 한국멀티미디어학회논문지
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• 제12권8호
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• pp.1082-1088
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• 2009

망막 질환의 진단에서 안저영상은 환자의 망막 상태에 대한 객관적인 평가와 기록에 중요하다. 특히 혈관의 분석은 당뇨병, 고혈압 등의 진단과 경과 관찰에 매우 중요하다. 혈관 영역을 검출하기 위해 톱-햇(Top-hat) 필터를 사용하여 균일하지 않은 배경 영상을 보상하고, 대비 제한의 적응적 히스토그램 보정(contrast limited adaptive histogram equalization) 방법을 적용하여 대비를 향상시켰다. 영상에 전처리를 한 후 헤이지안 행렬(hessian matrix)을 적용하여 혈관 성분을 검출한 결과 제안된 방법이 기존의 정합 필터(matched filter) 방법보다 약 1.3% 더 정확하였다. 결론으로 제안한 알고리즘은 안저 영상에서 혈관 영역을 검출하는데 있어서 기존 방법에 비해서 향상되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.379-379
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• 2010

Recent technical advances in OLEDs (organic light emitting devices) requires more and more the improvement in low operation voltage, long lifetime, and high luminance efficiency. Inverted top emission OLEDs (ITOLED) appeared to overcome these problems. This evolved to operate better luminance efficiency from conventional OLEDs. First, it has large open area so to be brighter than conventional OLEDs. Also easy integration is possible with Si-based driving circuits for active matrix OLED. But, a proper buffer layer for carrier injection is needed in order to get a good performance. The buffer layer protects underlying organic materials against destructive particles during the electrode deposition and improves their charge transport efficiency by reducing the charge injection barrier. Hexaazatriphenylene-hexacarbonitrile (HAT-CN), a discoid organic molecule, has been used successfully in tandem OLEDs due to its high workfunction more than 6.1 eV. And it has the lowest unoccupied molecular orbital (LUMO) level near to Fermi level. So it plays like a strong electron acceptor. In this experiment, we measured energy level alignment and hole current density on inverted OLED structures for hole injection. The normal film structure of Al/NPB/ITO showed bad characteristics while the HAT-CN insertion between Al and NPB greatly improved hole current density. The behavior can be explained by charge generation at the HAT-CN/NPB interface and gap state formation at Al/HAT-CN interface, respectively. This result indicates that a proper organic buffer layer can be successfully utilized to enhance hole injection efficiency even with low work function Al anode.