• 한국전자파학회논문지
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• 제28권11호
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• pp.880-885
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• 2017

기존에 제안된 AD-MUSIC 알고리즘을 이용하여 2차원 탐색 없이 1차원 탐색을 반복함으로써 DOD/DOA 추정이 가능하다. 본 논문에서는 계산량을 더욱 감소하기 위해 1차원 탐색에 Newton 기반 기법을 적용한다. 본 논문은 바이스태틱 MIMO 레이다 시스템의 수신신호 모델링과 AD-MUSIC의 유도과정을 보이고, 뉴턴 반복 기법을 AD-MUSIC에 적용한다. 추정 시, 기존의 AD-MUSIC 알고리즘의 성능과 계산량이 탐색 간격에 영향을 받는 것에 반해, AD-MUSIC의 성능과 뉴턴기법을 적용하는 본 논문의 방법인 경우, 탐색 간격에 관계없이 우수한 성능을 보이고, 계산량 또한 감소하는 효과를 보인다는 것을 시뮬레이션을 통해 보인다.

• 대한수학회논문집
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• 제25권4호
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• pp.655-669
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• 2010

In this paper we propose new primal-dual interior point methods (IPMs) for $P_*(\kappa)$ linear complementarity problems (LCPs) and analyze the iteration complexity of the algorithm. New search directions and proximity measures are defined based on a class of kernel functions, $\psi(t)=\frac{t^2-1}{2}-{\int}^t_1e{^{q(\frac{1}{\xi}-1)}d{\xi}$, $q\;{\geq}\;1$. If a strictly feasible starting point is available and the parameter $q\;=\;\log\;\(1+a{\sqrt{\frac{2{\tau}+2{\sqrt{2n{\tau}}+{\theta}n}}{1-{\theta}}\)$, where $a\;=\;1\;+\;\frac{1}{\sqrt{1+2{\kappa}}}$, then new large-update primal-dual interior point algorithms have $O((1\;+\;2{\kappa})\sqrt{n}log\;n\;log\;{\frac{n}{\varepsilon}})$ iteration complexity which is the best known result for this method. For small-update methods, we have $O((1\;+\;2{\kappa})q{\sqrt{qn}}log\;{\frac{n}{\varepsilon}})$ iteration complexity.

• 한국통신학회논문지
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• 제35권9C호
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• pp.743-747
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• 2010

본 논문은 빠른 연산(수렴)을 위한 적응 반복 하이브리드 영상 복원 알고리즘을 제안한다. 공간 영역의 국부제약 정보 설정을 위해 국부 영역의 분산, 평균, 국부 최대값을 이용하였다. 반복 기법을 이용하여 매 반복 해에서 얻어진 복원 영상으로부터 상기 제약 정보를 설정하고, 국부 완화도 결정을 위해 사용된다. 제안된 방식은 일반적인 RCLS(Regularized Constrained Least Squares) 방식에 비해 빠른 수렴속도와 더 좋은 성능을 얻을 수 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.301-305
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• 1996

$\mu$ theory can handle the parametric uncertainty and produces more non-conservative controller than H$_{\infty}$ control theory. However an existing solution of the theory, D-K iteration, creates a controller of huge order and cannot handle the real or mixed real-complex perturbation sets. In this paper, we use genetic algorithms to solve these problems of the D-K iteration method. The Youla parameterization is used to obtain all stabilizing controllers and the genetic algorithms determines the values of the state feedback gain, the observer gain, and Q parameter to minimize $\mu$, the structured singular value, of given system. From an example, we show that this method produces lower order controller which controls a real parameter-perturbed plant than D-K iteration method.

• 대한임베디드공학회논문지
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• 제9권5호
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• pp.285-292
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• 2014

The commonly used Newton-Raphson's floating-point number divider algorithm performs two multiplications in one iteration. In this paper, a tentative K'th Newton-Raphson's floating-point number divider algorithm which performs K times multiplications in one iteration is proposed. Since the number of multiplications performed by the proposed algorithm is dependent on the input values, the average number of multiplications per an operation in single precision and double precision divider is derived from many reciprocal tables with varying sizes. In addition, an error correction algorithm, which consists of one multiplication and a decision, to get exact result in divider is proposed. Since the proposed algorithm only performs the multiplications until the error gets smaller than a given value, it can be used to improve the performance of a floating point number divider unit. Also, it can be used to construct optimized approximate reciprocal tables.

• 대한임베디드공학회논문지
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• 제13권1호
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• pp.45-51
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• 2018

In this paper, a tentative Kth order Newton-Raphson's floating point number Nth root algorithm for K order convergence rate in one iteration is proposed by applying Taylor series to the Newton-Raphson root algorithm. Using the proposed algorithm, $F^{-1/N}$ and $F^{-(N-1)/N}$ can be computed from iterative multiplications without division. It also predicts the error of the algorithm iteration and iterates only until the predicted error becomes smaller than the specified value. Since the proposed algorithm only performs the multiplications until the error gets smaller than a given value, it can be used to improve the performance of a floating point number Nth root unit.

• Structural Engineering and Mechanics
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• 제70권1호
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• pp.43-54
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• 2019

Due to various numerical problems, crack analysis of reinforced concrete members using the finite element method is confronting with substantial difficulties, rendering the prediction of crack patterns and crack widths a formidable task. The root cause is that the conventional analysis methods are not capable of tracking the crack sequence and accounting for the stress relief and re-distribution during cracking. To address this deficiency, the crack queuing algorithm has been proposed. Basically, at each load increment, iterations are carried out and within each iteration step, only the most critical concrete element is allowed to crack and the stress re-distribution is captured in subsequent iteration by re-formulating the cracked concrete element and re-analysing the whole concrete structure. To demonstrate the effectiveness of the crack queuing algorithm, crack analysis of concrete members tested in the literature is performed with and without the crack queuing algorithm incorporated.

• Earthquakes and Structures
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• 제7권2호
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• pp.119-139
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• 2014

A new method is proposed for random vibration anaylsis of hysteretic systems subjected to non-stationary random excitations. With the Bouc-Wen model, motion equations of hysteretic systems are first transformed into quasi-linear equations by applying the concept of equivalent excitations and decoupling of the real and hysteretic displacements, and the derived equation system can be solved by either the precise time integration or the Newmark-${\beta}$ integration method. Combining the numerical solution of the auxiliary differential equation for hysteretic displacements, an explicit iteration algorithm is then developed for the dynamic response analysis of hysteretic systems. Because the computational cost for a large number of deterministic analyses of hysteretic systems can be significantly reduced, Monte-Carlo simulation using the explicit iteration algorithm is now viable, and statistical characteristics of the non-stationary random responses of a hysteretic system can be obtained. Numerical examples are presented to show the accuracy and efficiency of the present approach.

• 한국멀티미디어학회논문지
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• 제3권3호
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• pp.309-319
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• 2000

병렬 스케줄링의 목적은 다중프로세서 시스템 환경에서 병렬성을 가진 응용프로그램에 대해 최소의 동기화 오버헤드와 부하균등(load balance)을 달성하도록 스케줄링을 수행하는데 있다. 프로세서들이 병렬 반복(iteration)을 실행하기 위해서는 메모리로부터 반복들에 대한 chunk를 계산하고 할당받게 된다. 이때, 전역 메모리의 상호 배타적인 빈번한 접근으로 많은 스케쥴링 오버헤드 및 병목현상이 발생된다. 또한, 프로세서에게 할당된 chunk내 병렬 반복들의 분포가 서로 상이한 경우,각 chunk의 실행시간이 서로 달라 부하불균등의 원인이 되어 결과적으로 전체 스케쥴링 성능에 나쁜 영향을 준다. 따라서, 최소의 스케줄링 오버 헤드와 부하균등을 달성하기 위해 본 논문에 서는 기존의 방법들에서 문제점들을 도출하고, 자료의 국부성과 프로세서 동족성(affinity)을 고려한 병렬 루프 스케줄링 알고리즘을 제안한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.337-340
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• 1999

At each iteration, the path is either extended by adding a new node, or contracted by deleting its terminal node. When the destination becomes the terminal node of the path, the algorithm terminate. In the process of finding the shortest path to given destination, the algorithm visits other node, there by obtaining a shortest path from the origin to them. We show here that when the auction algorithm is applied to this equivalent program with some special rules for choosing the initial object prices and the person submitting a bid at each iteration, one obtains the generic form of the $\varepsilon$-relaxation method. Thus, the two methods are mathematically equivalent