• Title/Summary/Keyword: Computational algorithms

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Parallel Computing For Computational Geometry (컴퓨터 기하학을 위한 병렬계산)

  • O, Seung-Jun
    • Electronics and Telecommunications Trends
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    • v.4 no.1
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    • pp.93-117
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    • 1989
  • Computational Geometry is concerned with the design and analysis of computational algorithms which solve geometry problems. Geometry problems have a large number of applications areas such as pattern recognition, image processing, computer graphics, VLSI design and statistics since they involve inherently geometric problems for which efficient algorithms have to be developed. Several parallel algorithms, based on various parallel computation models, have been proposed for solving geometric problems. We review the current status of the parallel algorithms in computational geometry.

A Computational Approach to Definite NPs

  • Lee, Yong-Hun
    • Korean Journal of English Language and Linguistics
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    • v.3 no.1
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    • pp.89-108
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    • 2003
  • As pronouns are resolved with their antecedents, definite NPs may enter into the anaphora-antecedent relations with indefinite NPs. This paper is to provide faster and more efficient computational algorithms by which definite NPs are resolved effectively, For this purpose, this paper extends Chierchia's Binding Theory in Categorial Grammar, and definite NPs are resolved with their antecedents by similar algorithms that are used to reflexive resolution. In these algorithms, the relations between indefinite NP and definite NP are represented with λ-expressions, and definite NPs are resolved with their antecedent by λ-conversions.

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New Error Control Algorithms for Residue Number System Codes

  • Xiao, Hanshen;Garg, Hari Krishna;Hu, Jianhao;Xiao, Guoqiang
    • ETRI Journal
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    • v.38 no.2
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    • pp.326-336
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    • 2016
  • We propose and describe new error control algorithms for redundant residue number systems (RRNSs) and residue number system product codes. These algorithms employ search techniques for obtaining error values from within a set of values (that contains all possible error values). For a given RRNS, the error control algorithms have a computational complexity of $t{\cdot}O(log_2\;n+log_2\;{\bar{m}})$ comparison operations, where t denotes the error correcting capability, n denotes the number of moduli, and ${\bar{m}}$ denotes the geometric average of moduli. These algorithms avoid most modular operations. We describe a refinement to the proposed algorithms that further avoids the modular operation required in their respective first steps, with an increase of ${\lceil}log_2\;n{\rceil}$ to their computational complexity. The new algorithms provide significant computational advantages over existing methods.

Control-Gain Estimation of Energy Dissipation Control Algorithms (에너지소산 제어 알고리듬의 제어이득 산정)

  • 이상현;민경원;강상훈
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2004.04a
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    • pp.431-438
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    • 2004
  • This study is on control-gain estimation of energy dissipation control algorithms. Velocity feedback, bang-bang, and energy dissipation control algorithms are proposed based on the Lyapunov stability theory and their performances are evaluated and compared. Saturation problem is considered in the design of the velocity feedback and energy dissipation control algorithms, and chattering problem in bang-bang control is solved by using boundary layer. Numerical results show that the proposed control algorithms can dissipate the structural energy induced by wind loads efficiently, and thus provide good control performance.

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Design and Application of Learning Algorithms based on Computational Thinking for Changes in Prospective Elementary School Teachers' Perceptions about Computer Science (초등 예비교사의 컴퓨터과학에 대한 인식 변화를 위한 계산적 사고 기반 알고리즘 학습의 설계 및 적용)

  • Kim, Byeong-Su;Kim, Jong-Hoon
    • Journal of Fisheries and Marine Sciences Education
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    • v.24 no.4
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    • pp.528-542
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    • 2012
  • In this study, we designed and applied the learning program of various algorithms about computer science, which were based on computational thinking, to prospective elementary school teachers who were non-majors of this field. While they were learning, they could understand two fundamental functions of computational thinking: abstraction and automation. This learning program made them change their perceptions about computer science positively. They had been interested in learning algorithms and computer science itself, and they felt confident about teaching it.

Research Trends in Quantum Computational Algorithms for Cryptanalysis (암호해독을 위한 양자 계산 알고리즘의 최근 연구동향)

  • Bae, Eunok;Kim, Jeong San;Lee, Soojoon
    • Korean Journal of Optics and Photonics
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    • v.29 no.2
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    • pp.53-57
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    • 2018
  • In this paper, we mainly introduce some quantum computational algorithms that have exponential speedups over the best known classical algorithms, and summarize recent research achievements in quantum algorithms that can affect existing cryptosystems. Finally, we suggest a research direction that can improve these results more progressively.

Preliminary Structural Configuration Using 3D Graphic Software (3D 그래픽 S/W이용 초기 구조계획)

  • Kim, Nam-Hee;Koh, Hyung-Moo;Hong, Sung-Gul
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2011.04a
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    • pp.504-507
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    • 2011
  • 3D graphic softwares have brought design spaces beyond the limitations of Euclidean space. Moreover, as computational geometry has been considered together with algorithms, generative algorithms are being evolved. Recently 3D graphic softwares with the embedded generative algorithms allow designers to design free form curves and surfaces in a systematic way. While architectural design has been greatly affected by the advancement of 3D graphic technology, such attention has not given in the realm of structural design. Grasshopper is a platform in Rhino to deal with these Generative Algorithms and Associative modelling techniques. This study has tried to develop a module for preliminary structural configuration using Rhino with Grasshopper. To verify the proposed concept in this study, a module for designing a basic type of suspension structure is introduced.

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Low-Complexity Sub-Pixel Motion Estimation Utilizing Shifting Matrix in Transform Domain

  • Ryu, Chul;Shin, Jae-Young;Park, Eun-Chan
    • Journal of Electrical Engineering and Technology
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    • v.11 no.4
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    • pp.1020-1026
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    • 2016
  • Motion estimation (ME) algorithms supporting quarter-pixel accuracy have been recently introduced to retain detailed motion information for high quality of video in the state-of-the-art video compression standard of H.264/AVC. Conventional sub-pixel ME algorithms in the spatial domain are faced with a common problem of computational complexity because of embedded interpolation schemes. This paper proposes a low-complexity sub-pixel motion estimation algorithm in the transform domain utilizing shifting matrix. Simulations are performed to compare the performances of spatial-domain ME algorithms and transform-domain ME algorithms in terms of peak signal-to-noise ratio (PSNR) and the number of bits per frame. Simulation results confirm that the transform-domain approach not only improves the video quality and the compression efficiency, but also remarkably alleviates the computational complexity, compared to the spatial-domain approach.

A Comparative Study of PISO, SIMPLE, SIMPLE-C Algorithms in 3-dimensional Generalized Coordinate Systems (3차원 일반 좌표계에서의 PISO, SIMPLE, SIMPLE-C 알고리즘의 비교)

  • Park J. Y.;Baek J. H.
    • Journal of computational fluids engineering
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    • v.1 no.1
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    • pp.26-34
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    • 1996
  • The performance of the SIMPLE, SIMPLE-C and PISO algorithms for the treatment of the pressure-velocity coupling in fluid flow problems were examined by comparing the computational effort required to obtain the same level of the convergence. Example problems are circular duct and 90-degree bent square-duct. For circular duct case, laminar and turbulent flow were computed. For 90-degree bent square-duct case, laminar flow was simulated by the time-marching method as well as the iterative method. The convergence speed of the other two algorithms are not always superior to SIMPLE algorithm. SIMPLE algorithm is faster than SIMPLE-C algorithm in the simple laminar flow calculations. The application of the PISO algorithm in three dimensional general coordinates is not so effective as in two-dimensional ones. Since computational time of PISO algorithm is increased at each time step(or iterative step) in three dimension, the total convergence speed is not decreased. But PISO algorithm is stable for large time step by using time marching method,.

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A study on Variable Step Size algorithms for Convergence Speed Improvement of Frequency-Domain Adaptive Filter (주파수영역 적응필터의 수렴속도 향상을 위한 가변스텝사이즈 알고리즘에 관한 연구)

  • 정희준;오신범;이채욱
    • Proceedings of the IEEK Conference
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    • 2000.11d
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    • pp.191-194
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    • 2000
  • Frequency domain adaptive filter is effective to communication fields of many computational requirements. In this paper we propose a new variable step size algorithms which improves the convergence speed and reduces computational complexity for frequency domain adaptive filter. we compared MSE of the proposed algorithms with one of normalized FLMS using computer simulation of adaptive noise canceler based on synthesis speech.

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