• Journal of the Korean Data and Information Science Society
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• 제25권4호
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• pp.951-959
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• 2014

Recently Hazelton and Turlach (2009) proposed a weighted kernel density estimator for the deconvolution problem. In the case of Gaussian kernels and measurement error, they argued that the weighted kernel density estimator is a competitive estimator over the classical deconvolution kernel estimator. In this paper we consider weighted kernel density estimators when sample observations are contaminated by double exponentially distributed errors. The performance of the weighted kernel density estimators is compared over the classical deconvolution kernel estimator and the kernel density estimator based on the support vector regression method by means of a simulation study. The weighted density estimator with the Gaussian kernel shows numerical instability in practical implementation of optimization function. However the weighted density estimates with the double exponential kernel has very similar patterns to the classical kernel density estimates in the simulations, but the shape is less satisfactory than the classical kernel density estimator with the Gaussian kernel.

• Kyungpook Mathematical Journal
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• 제61권4호
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• pp.889-896
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• 2021

Let 𝜙 be an entire self map on ℂ and let 𝜓 be an entire function on ℂ. A weighted composition operator induced by 𝜙 with weight 𝜓 is given by C_𝜓,𝜙. In this paper we investigate under what conditions the weighted composition operators C_𝜓,𝜙 on the Fock space over ℂ induced by 𝜙 with weight of the form $k_c({\zeta})=e^{{\langle}{\zeta},c{\rangle}-{\frac{{\mid}c{\mid}^2}{2}}}$ is normaloid and essentially normaloid.

• 대한토목학회논문집
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• 제26권2A호
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• pp.383-390
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• 2006

본 연구에서는 급수전개를 이용한 추계론적 유한요소해석법의 개선을 위한 등가몬테카를로 추계장함수를 제안하고 1차 Taylor전개를 이용한 추계론적 유한요소해석법인 가중적분법에 적용하였다. 일반적으로 1차 Taylor전개를 이용하는 수치해석법에서의 응답변화도는 고려하고 있는 추계장의 분산계수에 대하여 선형거동을 보인다. 그러나 몬테카를로 해석의 경우 추계장 분산계수에 대하여 비선형 거동을 나타낸다. 이는 급수전개법의 1차 Taylor전개에 따른 선형특성에 기인한다. 따라서, 가중적분법에서 사용되는 Taylor전개된 변위벡터와 몬테카를로 해석에서의 변위벡터를 비교하고 이들 두 변위벡터 사이에 상호 불일치 하는 점을 고찰하여 몬테카를로 해석에서의 변위벡터와 등가의 변위벡터를 구성하고 이를 가중적분법에 적용하였다. 제안한 등가몬테카를로 추계장은 본래의 추계장 함수에 대한 고차함수로 주어진다. 평면구조에 대한 수치해석을 통하여 제안한 등가몬테카를로 추계장을 이용한 정식화의 타당성을 고찰하였다 새로운 정식화는 기존의 l차 가중적분법을 위한 정식화 과정과 유사하게 수행할 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.5928-5947
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• 2019

Multicast Mesh based Mobile Ad-hoc NETworks (MANETs) provide efficient data transmission in energy restraint areas without a fixed infrastructure. In this paper, the authors present an improved version of protocol SLIMMER developed by them earlier, and name it SLIMMER-SN. Most mesh-based protocols suffer from redundancy; however, the proposed protocol controls redundancy through the concept of forwarding nodes. The proposed protocol uses remaining energy of a node to decide its energy efficiency. For measuring stability, a new metric called Stability of Node (SN) has been introduced which depends on transmission range, node density and node velocity. For data transfer, a weighted cost function selects the most energy efficient nodes / most stable nodes or a weighted combination of both. This makes the node selection criteria more dynamic. The protocol works in two steps: (1) calculating SN and (2) using SN value in the weighted cost function for selection of nodes. The study compared the proposed protocol, with other mesh-based protocols PUMA and SLIMMER, based on packet delivery ratio (PDR), throughput, end-to-end delay and average energy consumption under different simulation conditions. Results clearly demonstrate that SLIMMER-SN outperformed both PUMA and SLIMMER.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(4)
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• pp.155-158
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• 2001

A new method for simultaneous multiple transmit focusing using orthogonal weighted FM chirp is proposed. Weighted chirp signals focused at different depths are transmitted at the same time. These chirp signals are mutually orthogonal in the approximate sense that the autocorrelation function of each signal has a narrow mainlobe width and low sidelobe levels, and the crosscorrellation function of any pair of the signals has smaller values than the sidelobe levels of each autocorrelation function. This means that each weighted chirp signal can be separately compressed into a short pulse, focused individually and combined with other focused beams to form a frame of image. Theoretically, any two chirp signals defined in two nonoverlapped frequency bands are mutually orthogonal. In the present work, however, a fractional overlap of adjacent frequency bands, by up to 25%, were permitted to design more chirp signals within a given transducer bandwidth. The crosscorrelation values due to the frequency overlap could be reduced by alternating the direction of frequency sweep of the adjacent chirp signals. The simulation results show that this method can improve the lateral resolution of image without sacrifice in the frame rate compared with the conventional pulse system.

• 대한수학회보
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• 제52권4호
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• pp.1383-1399
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• 2015

Let ${\mathbb{D}}=\{z{\in}{\mathbb{C}}:{\mid}z{\mid}<1\}$ be the open unit disk in the complex plane $\mathbb{C}$, ${\varphi}$ an analytic self-map of $\mathbb{D}$ and ${\psi}$ an analytic function in $\mathbb{D}$. Let D be the differentiation operator and $W_{{\varphi},{\psi}}$ the weighted composition operator. The boundedness and compactness of the product-type operator $W_{{\varphi},{\psi}}D$ from the weighted Bergman-Orlicz space to the weighted Zygmund space on $\mathbb{D}$ are characterized.

• 대한수학회논문집
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• 제35권4호
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• pp.1159-1170
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• 2020

We consider the weighted spaces ℓ^p(𝕊, 𝜑) and ℓ^p(𝕊, 𝜓) for 1 < p < +∞, where 𝜑 and 𝜓 are weights on 𝕊 (= ℕ or ℤ). We obtain a sufficient condition for ℓ^p(𝕊, 𝜓) to be multiplier weighted-space of ℓ^p(𝕊, 𝜑) and ℓ^p(𝕊, 𝜓). Our condition characterizes the last multiplier weighted-space in the case where 𝕊 = ℤ. As a consequence, in the particular case where 𝜓 = 𝜑, the weighted space ℓ^p(ℤ,𝜓) is a convolutive algebra.

• 대한수학회지
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• 제54권2호
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• pp.599-612
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• 2017

If ${\psi}$ is analytic on the open unit disk $\mathbb{D}$ and ${\varphi}$ is an analytic self-map of $\mathbb{D}$, the weighted composition operator $C_{{\psi},{\varphi}}$ is defined by $C_{{\psi},{\varphi}}f(z)={\psi}(z)f({\varphi}(z))$, when f is analytic on $\mathbb{D}$. In this paper, we study normal, cohyponormal, hyponormal and normaloid weighted composition operators on the Hardy and weighted Bergman spaces. First, for some weighted Hardy spaces $H^2({\beta})$, we prove that if $C_{{\psi},{\varphi}}$ is cohyponormal on $H^2({\beta})$, then ${\psi}$ never vanishes on $\mathbb{D}$ and ${\varphi}$ is univalent, when ${\psi}{\not\equiv}0$ and ${\varphi}$ is not a constant function. Moreover, for ${\psi}=K_a$, where |a| < 1, we investigate normal, cohyponormal and hyponormal weighted composition operators $C_{{\psi},{\varphi}}$. After that, for ${\varphi}$ which is a hyperbolic or parabolic automorphism, we characterize all normal weighted composition operators $C_{{\psi},{\varphi}}$, when ${\psi}{\not\equiv}0$ and ${\psi}$ is analytic on $\bar{\mathbb{D}}$. Finally, we find all normal weighted composition operators which are bounded below.

• Communications for Statistical Applications and Methods
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• 제17권2호
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• pp.183-191
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• 2010

Support vector quantile regression(SVQR) is capable of providing more complete description of the linear and nonlinear relationships among random variables. In this paper we propose an iterative reweighted least squares(IRWLS) procedure to solve the problem of SVQR with a weighted quadratic loss function. Furthermore, we introduce the generalized approximate cross validation function to select the hyperparameters which affect the performance of SVQR. Experimental results are then presented which illustrate the performance of the IRWLS procedure for SVQR.

• 한국음향학회지
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• 제18권5호
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• pp.78-82
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• 1999

본 연구는 잡음에 강한 음성 파라미터로써 널리 사용하는 가중 켑스트럼에 관한 연구이다. 특히 청각 모델인 PLP(Perceptual Linear Predictive)에서 켑스트럼을 추출 후 비대칭형 성문 펄스 파형 형태를 가중치 함수로 사용하는 방법을 제안한다. 또한 이러한 가중 켑스트럼을 성도 모델에서의 성도파형과 켑스트럼과 연관하여 분석하였다. 그리고 청각 모델인 PLP의 켑스트럼에 가중시켜 청각 모델과 성도 모델을 모두 적용한 음성 파라미터를 얻었다. 이러한 방법의 성능 평가를 위해 차량내 잡음과 길거리에서의 잡음 환경에서의 고립 단어 인식 실험을 하였다. 그리고 기존의 LP(Linear Prediction)에 의한 가중된 윈도우 켑스트럼 및 PLP에 의한 가중된 Liftering 켑스트럼 등과 비교하였다. 모의 실험 결과는 기존의 가중된 cepstrum 보다 제안하는 성문 가중 켑스트럼이 보다 높은 인식율을 보여준다.