• 대한수학교육학회지:수학교육학연구
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• 제16권4호
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• pp.273-295
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• 2006

본 연구는 수학학습 능력이 서로 다른 3학년 6명의 학생을 대상으로 총 6회의 실생활 문제 상황을 활용한 어림수업을 실시하여 어림에 어떤 변화가 보이는지 분석하고 어림학습 전과 후에 실생활 문제 상황 학습지를 투입하여 그에 대한 변화를 비교해 보았다. 실생활 문제 상황을 활용하여 역할극으로 진행된 어림수업에서 학생들은 자신의 생활과 친숙한 문제 상황 속에서 어림을 사용하였으며, 문제 상황에 따라 적절한 자리 수를 결정할 수 있음을 확인하였다.

• 한국초등수학교육학회지
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• 제24권1호
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• pp.53-87
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• 2020

본 연구는 초등학교 수학에서의 계산어림활동을 고찰함으로써 계산어림지도를 위한 개선방향을 모색하고자 2015 개정 초등학교 수학과 교육과정과 그에 따른 수학교과서 및 교사용지도서에 포함된 계산어림 관련 내용을 살펴보았다. 이를 통해서 전학년군에 걸쳐서 계산어림을 강조할 필요가 있으며, 계산어림의 효과적인 지도를 위해서 계산어림하기, 어림과정설명하기, 어림값과 계산값 비교를 통한 계산결과의 타당성 검증하기 등을 체계적으로 지도하는 것이 필요하며, 연산관련단원에서 계산어림관련 활동을 좀 더 강화하는 것이 필요하다는 것을 알 수 있었다.

• Journal of Positioning, Navigation, and Timing
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• 제11권2호
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• pp.91-98
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• 2022

In the next generation wireless communication system, the beamforming technique based on a massive antenna is one of core technologies for transmitting and receiving huge amounts of data, efficiently and accurately. For highly performed and highly reliable beamforming, it is required to accurately estimate the Angle of Arrival (AOA) for the desired signal incident to an antenna. Employing the massive antenna with a large number of elements, although the accuracy of the AOA estimation is enhanced, its computational complexity is dramatically increased so much that real-time communication is difficult. In order to improve this problem, AOA estimation algorithms based on the massive antenna with the low computational complexity have been actively studied. In this paper, we compute and analyze the computational complexity of the cascade AOA estimation algorithm based on the Flexible Massive Concentric Circular Array (FMCCA). In addition, its computational complexity is compared to conventional AOA estimation techniques such as the Multiple Signal Classification (MUSIC) algorithm with the high resolution and the Only Beamspace MUSIC (OBM) algorithm.

• 한국수학교육학회지시리즈A:수학교육
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• 제59권3호
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• pp.255-269
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• 2020

본 연구에서는 의도-작성-실행된 교육과정이라는 일련의 다차원 교육과정적 관점에서 초등 수학의 연산 중 기본이 되는 덧셈과 뺄셈의 어림셈 지도 방식에 대하여 논의하였다. 실행된 교육과정에서 출발하여 작성-의도된 교육과정의 상향식 피드백 방식으로 덧셈과 뺄셈의 어림셈 지도에 대한 교수·학습 방법 면에서의 쟁점 사항을 파악하고 이를 개선하기 위한 시사점을 도출하였다.

• Journal of Positioning, Navigation, and Timing
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• 제13권3호
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• pp.277-287
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• 2024

In satellite systems, efficient communication and observation require identifying of specific signal arrival points using onboard antenna systems. When utilizing massive array antennas to estimate the angle of arrival (AOA) of signals, traditional high-performance AOA estimation algorithms such as Multiple Signal Classification (MUSIC) encounter extremely high complexity due to the numerous individual antenna elements. Although, in order to improve this computational complexity problem, the cascade AOA estimation algorithm with CAPON and beamspace-MUSIC was recently proposed, the comparison of the computational complexity of the proposed algorithm across different massive array antenna configurations has not yet been conducted. In this paper, we provide the analyzed results of the computational complexity of the proposed cascade algorithm based on various massive array antennas, and determine an optimal antenna configuration for the efficient AOA estimation in satellite systems.

• Communications for Statistical Applications and Methods
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• 제25권4호
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• pp.431-442
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• 2018

This paper highlights the computational explosion issues in the autoregressive moving average approach of frequency estimation of sinusoidal data with a large sample size. A new algorithm is proposed to circumvent the computational explosion difficulty in the conditional least-square estimation method. Notice that sinusoidal pattern can be generated by a non-invertible non-stationary autoregressive moving average (ARMA) model. The computational explosion is shown to be closely related to the non-invertibility of the equivalent ARMA model. Simulation studies illustrate the computational explosion phenomenon and show that the proposed algorithm can efficiently overcome computational explosion difficulty. Real data example of sunspot number is provided to illustrate the application of the proposed algorithm to the time series data exhibiting sinusoidal pattern.

• Journal of the Korean Statistical Society
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• 제10권
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• pp.91-96
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• 1981

The development of Minimum Norm Quadratic Unbiased Estimation (MINQUE) has introduced a unified approach for the estimation of variance components in general linear models. The computational problem has been studied by Liu and Senturia (1977) and Goodnight (1978, setting a-priori values to 0). This paper further simplifies the computation and gives efficient and compact computational algorithm for the MINQUE and dispersion matrix in general linear random model.

• 한국전자통신학회논문지
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• 제17권6호
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• pp.1055-1062
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• 2022

매시브 배열 안테나를 이용한 매시브 MIMO(: Multi Input Multi Output) 기술을 이용하기 위해서는 신호의 도래각(Angle of Arrival : AOA) 파악이 필수적으로 요구된다. 매시브 배열 안테나를 하면 기존 AOA 추정 알고리즘은 뛰어난 추정 성능을 갖지만, 안테나 요소 수에 비례하여 계산복잡도가 증가하는 단점이 있다. 이러한 문제를 해결하기 위해 캐스케이드 AOA 추정 알고리즘이 제안되었으며 다수의 논문을 통해 단일 형상의 (비)매시브 배열 안테나에 대한 성능이 입증되었다. 하지만 단일 및 이중 림 어레이 안테나가 적용된 캐스케이드 AOA 추정 알고리즘의 계산복잡도 비교는 이루어지지 않았다. 본 논문에서는 단일 및 이중 림 어레이를 캐스케이드 AOA 추정 알고리즘에 적용된 경우 AOA 추정을 위한 계산복잡도를 비교 분석한다.

• IEIE Transactions on Smart Processing and Computing
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• 제3권6호
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• pp.382-387
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• 2014

A computational approach to depth estimations using a color over lapped integral imaging system is presented. The proposed imaging system acquires multiple color images simultaneously through a single lens with an array of multiple pinholes that are distributed around the optical axis. This paper proposes a computational model of the relationship between the real distance of an object and the disparity among different color images. The proposed model can serve as a computational basis of a single camera-based depth estimation.

• 한국통신학회논문지
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• 제21권5호
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• pp.1109-1122
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• 1996

Generally, moving images contain the various components in motions, which reange from a static object and background to a fast moving object. To extract the accurate motion parameters, we must consider the various motions. That requires a wide search egion in motion estimation. The wide search, however, causes a high computational complexity. If we have a few knowledge about the motion direction and magnitude before motion estimation, we can determine the search location and search window size using the already-known information about the motion. In this paper, we present a local adaptive motion estimation approach that predicts a block motion based on spatio-temporal neighborhood blocks and adaptively defines the search location and search window size. This paper presents a technique for reducing computational complexity, while having high accuracy in motion estimation. The proposed algorithm is introduced the forward and backward projection techniques. The search windeo size for a block is adaptively determined by previous motion vectors and prediction errors. Simulations show significant improvements in the qualities of the motion compensated images and in the reduction of the computational complexity.