• 한국재난정보학회 논문집
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• 제20권2호
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• pp.293-301
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• 2024

연구목적: 환경부 통계에 의하면 2014년부터 2023년까지 국내 화재·폭발사고가 132건 이상에 이르는 것을 알 수 있다. 이중 화재·폭발사고는 발생 시 규모나 영향이 상대적으로 매우 커서 주의가 필요하다. 본 연구에서는 인화성의 유해화학물질 취급 시 실내 취급시설의 적정 환기율을 계산하는 새로운 합리적인 방법을 제안하였다. 연구방법: 취급시설의 바닥면적만을 기준으로 한 현행 화학물질관리법 상 계산방법과 비교하여 보다 합리적인 새로운 방법은 취급하는 유해화학물질의 물리화학적인 특성을 기반으로 계산하는 방법이다. 연구결과:물리화학적 특성을 고려하여 계산한 결과 인화성물질 178종 중 168종인 약 94%이 환기량 기준에 적합하였다. 그러나 일부 물질은 과소환기 및 과대환기를 요구하는 것으로 나타났다. 결론:본 연구를 통해 합리적인 필요환기량 산정방법을 제안하였고 이를 통해 근로자의 안전을 확보하고 생명을 보호해야 할 것이다.

• Communications for Statistical Applications and Methods
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• 제3권3호
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• pp.271-282
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• 1996

this paper deal with the estimation of the power spectral density function of time series. A kernel estimator which is based on local average is defined and the rates of convergence of the pointwise, $$L_2$-norm; and; $L{\infty}$-norm associated with the estimator are investigated by restricting as to kernels with suitable assumptions. Under appropriate regularity conditions, it is shown that the optimal rate of convergence for 0$N^{-r}$ both in the pointwiseand $$L_2$-norm, while; $N^{r-1}(logN)^{-r}$is the optimal rate in the $L{\infty}-norm$. Some examples are given to illustrate the application of main results.

• 대한수학회지
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• 제55권4호
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• pp.849-875
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• 2018

The purpose of this paper is to present an operator method of regularization for the problem of finding a solution of a system of nonlinear ill-posed equations with a monotone hemicontinuous mapping and N inverse-strongly monotone mappings in Banach spaces. A regularization parameter choice is given and convergence rate of the regularized solutions is estimated. We also give the convergence and convergence rate for regularized solutions in connection with the finite-dimensional approximation. An iterative regularization method of zero order in a real Hilbert space and two examples of numerical expressions are also given to illustrate the effectiveness of the proposed methods.

• 대한수학회보
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• 제50권3호
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• pp.823-832
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• 2013

We present a new algorithm for solving a system of nonlinear equations with convex constraints which combines proximal point and projection methodologies. Compared with the existing projection methods for solving the problem, we use a different system of linear equations to obtain the proximal point; and moreover, at the step of getting next iterate, our projection way and projection region are also different. Based on the Armijo-type line search procedure, a new hyperplane is introduced. Using the separate property of hyperplane, the new algorithm is proved to be globally convergent under much weaker assumptions than monotone or more generally pseudomonotone. We study the convergence rate of the iterative sequence under very mild error bound conditions.

• 한국음향학회지
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• 제15권5호
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• pp.30-37
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• 1996

통신 시스템에서 LMS 알고리즘을 이용하여 설계한 적응 등화기는 구조의 간단함과 효율성에 비해 수렴 속도가 느린 단점이 있다. 본 논문에서는 이러한 단점을 보완하기 위해 웨이브렛 변환 평면에서 적응 동기화를 설계하여 채널의 왜곡정도와 필터 차수의 변화에 따른 수렴 속도를 시평면 LMS 알고리즘을 이용해 설계한 등화기와 비교하였다. 시뮬레이션결과 웨이브렛 평면에서의 적응 등화기가 기존의 등화기보다 우수한 성능 향상을 보였다.

• International Journal of Aeronautical and Space Sciences
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• 제2권1호
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• pp.1-11
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• 2001

The time implicit point SGS scheme is applied to compute hypersonic viscous flows in thermochemical nonequilibrium. The performance of the point SGS scheme is then compared with those of the line SGS and the LU-SGS schemes. Comparison of convergence histories with the effect of multiple forward and backward sweeps are made for the flow over a 2D cylinder experimentally studied by Hornung and the flow over a hemisphere at conditions corresponding to the peak heating condition during the reentry flight of an SSTO vehicle. Results indicate that the point SGS scheme with multiple sweeps is as robust and efficient as the line SGS scheme. For the point SGS and the LU-SGS scheme, the rate of improvement in convergence is largest with two sweep cycles. However, for the line SGS scheme, it is found that more than one sweep cycle deteriorates the convergence rate.

• ETRI Journal
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• 제31권6호
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• pp.755-764
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• 2009

This paper presents a switched self-biasing and a tail current-shaping technique to suppress the 1/f noise from a tail current source in differential cross-coupled inductance-capacitance (LC) voltage-controlled oscillators (VCOs). The proposed LC VCO has an amplitude control characteristic due to the creation of negative feedback for the oscillation waveform amplitude. It is fabricated using a 0.13 ${\mu}m$ CMOS process. The measured phase noise is -117 dBc/Hz at a 1 MHz offset from a 4.85 GHz carrier frequency, while it draws 6.5 mA from a 0.6 V supply voltage. For frequency tuning, process variation, and temperature change, the amplitude change rate of the oscillation waveform in the proposed VCO is 2.1 to 3.2 times smaller than that of an existing VCO with a fixed bias. The measured amplitude change rate of the oscillation waveform for frequency tuning from 4.55 GHz to 5.04 GHz is 131 pV/Hz.

• 호남수학학술지
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• 제39권1호
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• pp.1-25
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• 2017

In this paper, we introduce a new scheme namely: CUIA-iterative scheme and utilize the same to prove a strong convergence theorem for quasi contractive mappings in Banach spaces. We also establish the equivalence of our new iterative scheme with various iterative schemes namely: Picard, Mann, Ishikawa, Agarwal et al., Noor, SP, CR etc for quasi contractive mappings besides carrying out a comparative study of rate of convergences of involve iterative schemes. The present new iterative scheme converges faster than above mentioned iterative schemes whose detailed comparison carried out with the help of different tables and graphs prepared with the help of MATLAB.

• 한국통신학회논문지
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• 제30권2B호
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• pp.21-26
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• 2005

효율적인 통신망에서의 라우팅을 위해, 개선된 에너지 함수를 가지는 Hopfield 신경망에 의한 알고리즘이 본 논문에서 제안되었는데, 보다 높은 최적경로 형성과 안정적 수렴의 결과를 목적으로 한다. 20-50 개의 노드를 가지며, 무작위 연결 비용이 인가되는 3,000 개의 통신망에 대한 실험의 결과에서 볼 때, 기존의 신경망을 이용한 알고리즘들이 노드 수가 많은 망 환경에서 수렴하지 않거나, 최적경로가 형성이 되지 않은 경우가 많았지만 제안된 알고리즘은 최적경로 형성에서 기존 알고리즘 보다 약 65%의 개선을 하였고 또한 기존 알고리즘 보다 약 50% 정도 수렴이 잘 되는 것이 확인되었다.

• Kyungpook Mathematical Journal
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• 제62권3호
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• pp.467-484
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• 2022

In this work, we define bivariate Bernstein-Kantorovich type operators on a triangular domain and obtain some approximation results for these operators. We start off by computing some moment estimates and prove a Korovkin type convergence theorem. Then, we estimate the rate of convergence using the partial and complete modulus of continuity, and derive a Voronovskaya-type asymptotic theorem. Further, we calculate the order of approximation with regard to the Peetre's K-functional and a Lipschitz type class. In addition, we construct the associated GBS type operators and compute the rate of approximation using the mixed modulus of continuity and class of the Lipschitz of Bögel continuous functions for these operators. Finally, we use the two operators to approximate example functions in order to compare their convergence.