• 제목/요약/키워드: ${\Delta}$-convergence

검색결과 197건 처리시간 0.027초

진단기준 차이가 폭주부족의 빈도에 미치는 영향 (Influence of Different Diagnostic Criteria on Frequency of Convergence Insufficiency)

  • 유동식;조현국;문병연
    • 한국안광학회지
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    • 제21권3호
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    • pp.235-242
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    • 2016
  • 목적: 다른 진단기준의 적용이 폭주부족의 빈도에 미치는 영향을 알아보고자 하였다. 방법: 평균 나이 22.54세(20~27세)의 81명을 대상으로 평가하였다. 굴절검사 후 조절성 시표에 의한 폭주근점(NPC)검사, 폰 그래페에 의한 사위검사, 포롭터에 의한 양성융합이향운동(PFV)검사를 실시하였다. 근거리 외사위가 원거리 사위보다 큰 기준($exo{\geq}4{\Delta}$, >$6{\Delta}$), 융합이향운동 기준(PFV의 흐린점 ${\leq}11{\Delta}$, PFV의 분리점 ${\leq}15{\Delta}$, 쉐어드기준, 퍼시발 기준), 폭주근점 기준($NPC{\geq}6cm$, ${\geq}7.5cm$, >10 cm)을 이용하여 폭주부족을 진단하였다. 결과: 하나의 진단기준에 의한 폭주부족 빈도는 6.2%~77.8%의 범위로 분포하였고, 기준에 따라 과대평가되거나 과소평가되었다. 두 가지 이상의 진단기준에 의한 폭주부족 빈도는 6.2%~43.2%로 변동성이 줄어들었으며, 특히 사위 기준과 쉐어드를 포함하는 진단기준일 때 폭주부족의 빈도는 24.7%~28.4%로 줄어들어 낮은 변동성을 보였다. 점수 척도의 전체 징후와 사위, 측정 값의 사위와 쉐어드 기준의 상관관계가 각각 0.772와 -0.654로 유의하게 높았다(p<0.001). 폭주근점 기준은 변동성이 컸으며, 다른 진단기준과의 상관관계는 낮거나 유의하지 않았다. 징후에 따른 폭주부족의 진단기준과 적용순서로 $exo{\geq}4{\Delta}$, 쉐어드 기준, 폭주근점${\geq}7.5cm$로 제시한다. 결론: 폭주부족의 빈도는 진단기준에 따라 과대, 과소평가 될 가능성이 있다. 임상징후로서 사위, 쉐어드 기준과 폭주근점의 절단값과 절차는 폭주부족과 관련된 진단에서 명확하게 제시되어야 한다.

퍼지 RBF 네트워크의 학습 성능 개선 (Learning Performance Improvement of Fuzzy RBF Network)

  • 김광백
    • 한국멀티미디어학회논문지
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    • 제9권3호
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    • pp.369-376
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    • 2006
  • 본 논문에서는 퍼지 RBF네트워크의 학습 성능을 개선하기 위하여 Delta-bar-Delta 알고리즘을 적용하여 학습률을 동적으로 조정하는 개선된 퍼지 RBF 네트워크를 제안한다. 제안된 학습 알고리즘은 일반화된 델타 학습 방법에 퍼지 C-Means 알고리즘을 결합한 방법으로, 중간층의 노드를 자가 생성하고 중간층과 출력층의 학습에는 일반화된 델타 학습 방법에 Delta-bar-Delta 알고리즘을 적용하여 학습률을 동적으로 조정하여 학습 성능을 개선한다. 제안된 RBF 네트워크의 학습 성능을 평가하기 위하여 컨테이너 영상에서 추출한 40개의 식별자를 학습 데이터로 적용한 결과, 기존의 ART2 기반 RBF 네트워크와 기존의 퍼지 RBF 네트워크 보다 학습 시간이 적게 소요되고, 학습의 수렴성이 개선된 것을 확인하였다.

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Delta-form-based method of solving high order spatial discretization schemes for neutron transport

  • Zhou, Xiafeng;Zhong, Changming;Li, Fu
    • Nuclear Engineering and Technology
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    • 제53권7호
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    • pp.2084-2094
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    • 2021
  • Delta-form-based methods for solving high order spatial discretization schemes are introduced into the reactor SN transport equation. Due to the nature of the delta-form, the final numerical accuracy only depends on the residuals on the right side of the discrete equations and have nothing to do with the parts on the left side. Therefore, various high order spatial discretization methods can be easily adopted for only the transport term on the right side of the discrete equations. Then the simplest step or other robust schemes can be adopted to discretize the increment on the left hand side to ensure the good iterative convergence. The delta-form framework makes the sweeping and iterative strategies of various high order spatial discretization methods be completely the same with those of the traditional SN codes, only by adding the residuals into the source terms. In this paper, the flux limiter method and weighted essentially non-oscillatory scheme are used for the verification purpose to only show the advantages of the introduction of delta-form-based solving methods and other high order spatial discretization methods can be also easily extended to solve the SN transport equations. Numerical solutions indicate the correctness and effectiveness of delta-form-based solving method.

COMMON FIXED POINT OF GENERALIZED ASYMPTOTIC POINTWISE (QUASI-) NONEXPANSIVE MAPPINGS IN HYPERBOLIC SPACES

  • Saleh, Khairul;Fukhar-ud-din, Hafiz
    • Korean Journal of Mathematics
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    • 제28권4호
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    • pp.915-929
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    • 2020
  • We prove a fixed point theorem for generalized asymptotic pointwise nonexpansive mapping in the setting of a hyperbolic space. A one-step iterative scheme approximating common fixed point of two generalized asymptotic pointwise (quasi-) nonexpansive mappings in this setting is provided. We obtain ∆-convergence and strong convergence theorems of the iterative scheme for two generalized asymptotic pointwise nonexpansive mappings in the same setting. Our results generalize and extend some related results in the literature.

Molecular Characterization and Expression Analysis of the Peroxisome Proliferator Activated Receptor Delta (PPARδ) Gene before and after Exercise in Horse

  • Cho, Hyun-Woo;Shin, Sangsu;Park, Jeong-Woong;Choi, Jae-Young;Kim, Nam-Young;Lee, Woon-Kyu;Lee, Hak-Kyo;Song, Ki-Duk;Cho, Byung-Wook
    • Asian-Australasian Journal of Animal Sciences
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    • 제28권5호
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    • pp.697-702
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    • 2015
  • While athletic abilities such as speed, endurance and recovery are important in the horse, genes related to these abilities have not been extensively investigated. Here, we characterized the horse peroxisome proliferator-activated receptor delta ($PPAR{\delta}$) gene and analyzed the expression of $PPAR{\delta}$ during exercise. $PPAR{\delta}$ is a known regulator of ${\beta}$-oxidation, muscle fiber transformation, and running endurance. Through evolutionary analysis using the synonymous and non-synonymous mutation ratio, it was revealed that positive selection occurred in the horse $PPAR{\delta}$ gene. Two important domains related to nuclear hormone receptors, C4 zinc finger and ligand binding domain, were also found to be conserved well in horse $PPAR{\delta}$. Horse $PPAR{\delta}$ was expressed ubiquitously in many tissues, but the expression level was various depending on the tissues. In the skeletal muscle, $PPAR{\delta}$ increased about 2.5 folds after 30 min of exercise. Unlike in muscle, the increase of $PPAR{\delta}$ expression was observed at 60 min but not 30 min of exercise in leukocytes. This finding might be useful for testing the endurance of horse using blood samples. Conclusively, the horse $PPAR{\delta}$ gene is evolutionarily conserved well and can be used as a biomarker of endurance in horse.

MONOTONE EMPIRICAL BAYES TESTS FOR SOME DISCRETE NONEXPONENTIAL FAMILIES

  • Liang, Tachen
    • Journal of applied mathematics & informatics
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    • 제23권1_2호
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    • pp.153-165
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    • 2007
  • This paper deals with the empirical Bayes two-action problem of testing $H_0\;:\;{\theta}{\leq}{\theta}_0$: versus $H_1\;:\;{\theta}>{\theta}_0$ using a linear error loss for some discrete nonexponential families having probability function either $$f_1(x{\mid}{\theta})=(x{\alpha}+1-{\theta}){\theta}^x\prod\limits_{j=0}^x\;(j{\alpha}+1)$$ or $$f_2(x{\mid}{\theta})=[{\theta}\prod\limits_{j=0}^{x-1}(j{\alpha}+1-{\theta})]/[\prod\limits_{j=0}^x\;(j{\alpha}+1)]$$. Two empirical Bayes tests ${\delta}_n^*\;and\;{\delta}_n^{**}$ are constructed. We have shown that both ${\delta}_n^*\;and\;{\delta}_n^{**}$ are asymptotically optimal, and their regrets converge to zero at an exponential decay rate O(exp(-cn)) for some c>0, where n is the number of historical data available when the present decision problem is considered.

Enhanced RBF Network by Using Auto- Turning Method of Learning Rate, Momentum and ART2

  • Kim, Kwang-baek;Moon, Jung-wook
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2003년도 Proceeding
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    • pp.84-87
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    • 2003
  • This paper proposes the enhanced REF network, which arbitrates learning rate and momentum dynamically by using the fuzzy system, to arbitrate the connected weight effectively between the middle layer of REF network and the output layer of REF network. ART2 is applied to as the learning structure between the input layer and the middle layer and the proposed auto-turning method of arbitrating the learning rate as the method of arbitrating the connected weight between the middle layer and the output layer. The enhancement of proposed method in terms of learning speed and convergence is verified as a result of comparing it with the conventional delta-bar-delta algorithm and the REF network on the basis of the ART2 to evaluate the efficiency of learning of the proposed method.

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Binary Power Amplifier with 2-Bit Sigma-Delta Modulation Method for EER Transmitter

  • Lim, Ji-Youn;Cheon, Sang-Hoon;Kim, Kyeong-Hak;Hong, Song-Cheol;Kim, Dong-Wook
    • ETRI Journal
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    • 제30권3호
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    • pp.377-382
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    • 2008
  • A novel power amplifier for a polar transmitter is proposed to achieve better spectral performance for a wideband envelope signal. In the proposed scheme, 2-bit sigma-delta (${\Sigma}{\Delta}$) modulation of the envelope signal is introduced, and the power amplifier configuration is modified in a binary form to accommodate the 2-bit digitized envelope signals. The 2-bit ${\Sigma}{\Delta}$ modulator lowers the noise of the envelope signal by fine quantization and thus enhances the spectral property of the RF signal. The Ptolemy simulation results of the proposed structure show that the spectral noise is reduced by 10 dB in a full transmit band of the EDGE system. The dynamic range is also enhanced. Since the performance is improved without increasing the over-sampling ratio, this technique is best suited for wireless communication with high data rates.

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초음속 노즐에서의 약한 수직충격파와 난류경계층의 간섭(제1편, 시간적평균 흐름의 특성) (Weak Normal Shock Wave/Turbulent Boundary Layer Interaction in a Supersonic Nozzle(1st Report, Time-Mean Flow Characteristics))

  • 홍종우
    • 한국산업융합학회 논문집
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    • 제2권2호
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    • pp.115-124
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    • 1999
  • The interaction of weak normal shock wave with turbulent boundary layer in a supersonic nozzle was investigated experimentally by wall static pressure measurements and by schlieren optical observations. The lime-mean flow in the interaction region was classified into four patterns according to the ratio of the pressure $p_k$ at the first kink point in the pressure distribution of the interaction region to the pressure $p_1$ just upstream of the shock. It is shown for any flow pattern that the wall static pressure rise near the shock foot can be described by the "free interaction" which is defined by Chapman et al. The ratio of the triple point height $h_t$ of the bifurcated shock to the undisturbed boundary layer thickness ${\delta}_1$ upstream of the interaction increases with the upstream Mach number $M_1$, and for a fixed $M_1$, the normalized triple point height $h_t/{\delta}_1$ decreases with increasing ${\delta}_1/h$, where h is the duct half-height.

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안구돌출도와 시기능의 상관관계 분석 (Correlations between Exophthalmetry and Visual Functions)

  • 김근희;노혜란
    • 한국안광학회지
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    • 제20권3호
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    • pp.325-331
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    • 2015
  • 목적: 안구돌출도와 시기능의 상관관계를 알아보고자 하였다. 방법: 안질환과 전신질환이 없는 성인 남녀 200명(20~50대 각 50명)을 대상으로 안구돌출도와 시기능을 검사하였다. 허텔 안구돌출계로 안구돌출도를 측정하였고, 근시, 외사위, 내사위, 폭주 근점, 조절 근점 등 시기능 요소에 대한 검사를 3회 반복하여 실시하였다. 결과: 안구돌출도는 $13.59{\pm}1.10mm$, 근시, 원거리 외사위, 근거리 외사위, 폭주 근점 그리고 조절 근점은 $-2.48{\pm}1.91D$, $3.51{\pm}1.78{\Delta}$, $5.73{\pm}2.44{\Delta}$, $9.63{\pm}2.82cm$, $21.73{\pm}10.28cm$로 나타났다. 안구돌출도가 증가할수록 나안시력, 근시 그리고 난시도는 유의하게 감소하였다. 반면 원거리 외사위, 원거리 내사위, 근거리 외사위, 폭주 근점 그리고 조절 근점은 안구돌출도가 증가할수록 유의하게 증가하였다. 결론: 시기능과 안구돌출도의 유의한 관계는 양안시 처방과 검사를 위한 임상적 기준이 될 수 있을 것으로 사료된다.