• 제목/요약/키워드: computational algorithms

검색결과 1,466건 처리시간 0.023초

Implementation of Presence and Absence of Blocking Effects: A Categorial Grammar Approach to Chinese and Korean

  • Lee, Yong-Hun
    • 한국언어정보학회:학술대회논문집
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    • 한국언어정보학회 2007년도 정기학술대회
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    • pp.275-284
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    • 2007
  • Among the languages that allow long-distance reflexives, some languages have blocking effects, whereas others don't. The goal of this paper is to provide computational algorithms that can handle presence and absence of blocking effects of long-distance reflexives. We will examine the blocking effects in Chinese and Korea and develop computational algorithms for handling blocking effects in those two languages. The algorithms will be developed by incorporating Chierchia's Binding Theory into Steedman's Combinatory Categorial Grammar (CCG). Through the analyses and implementations, this paper illustrates how blocking effects can be implemented computationally.

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구조최적화를 위한 분산 복합 유전알고리즘 (Distributed Hybrid Genetic Algorithms for Structural Optimization)

  • 우병헌;박효선
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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    • pp.203-210
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    • 2002
  • The great advantages on the Genetic Algorithms(GAs) are ease of implementation, and robustness in solving a wide variety of problems, several GAs based optimization models for solving complex structural problems were proposed. However, there are two major disadvantages in GAs. The first disadvantage, implementation of GAs-based optimization is computationally too expensive for practical use in the field of structural optimization, particularly for large-scale problems. The second problem is too difficult to find proper parameter for particular problem. Therefore, in this paper, a Distributed Hybrid Genetic Algorithms(DHGAs) is developed for structural optimization on a cluster of personal computers. The algorithm is applied to the minimum weight design of steel structures.

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탐색 범위를 적용한 비교 루틴 고속 블록 움직임 추정방법 알고리듬 (Comparison Fast-Block Matching Motion Estimation Algorithm for Adaptive Search Range)

  • 임유찬;밍경육;정정화
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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    • pp.295-298
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    • 2002
  • This paper presents a fast block-matching algorithm to improve the conventional Three-Step Search (TSS) based method. The proposed Comparison Fast Block Matching Algorithm (CFBMA) begins with DAB for adaptive search range to choose searching method, and searches a part of search window that has high possibility of motion vector like other partial search algorithms. The CFBMA also considers the opposite direction to reduce local minimum, which is ignored in almost conventional based partial search algorithms. CFBMA uses the summation half-stop technique to reduce the computational load. Experimental results show that the proposed algorithm achieves the high computational complexity compression effect and very close or better image quality compared with TSS, SES, NTSS based partial search algorithms.

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Feature Recognition: the State of the Art

  • JungHyun Han
    • 한국CDE학회논문집
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    • 제3권1호
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    • pp.68-85
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    • 1998
  • Solid modeling refers to techniques for unambiguous representations of three-dimensional objects. Feature recognition is a sub-discipline focusing on the design and implementation of algorithms for detecting manufacturing information such as holes, slots, etc. in a solid model. Automated feature recognition has been an active research area in stolid modeling for many years, and is considered to be a critical component for CAD/CAM integration. This paper gives a technical overview of the state of the art in feature recognition research. Rather than giving an exhaustive survey, I focus on the three currently dominant feature recognition technologies: graph-based algorithms, volumetric decomposition techniques, and hint-based geometric reasoning. For each approach, I present a detailed description of the algorithms being employed along with some assessments of the technology. I conclude by outlining important open research and development issues.

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RAPTOR 프로그래밍 교육도구를 이용한 알고리즘 교육 (Education of Algorithms Using the RAPTOR Programming Educational Tool)

  • 김성율;이종연
    • 컴퓨터교육학회논문지
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    • 제18권6호
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    • pp.23-31
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    • 2015
  • 소프트웨어 교육은 건전한 정보윤리의식을 바탕으로 컴퓨팅 사고력 기반의 문제해결력을 기르는데 목적을 두고 있다. 이러한 목적을 달성하기 위해서 많은 교육기관에서 EPL(Educational Programming Language), 피지컬 컴퓨팅, 로봇 등 다양한 교육이 시도되고 있다. 하지만 특정 EPL과 상용 제품 등에 초점이 맞추어진 교육은 컴퓨팅 사고력 향상에 초점을 맞추고 있는 소프트웨어 교육의 창의성 교육을 획일적으로 유도할 우려가 있다. 따라서 본 논문에서는 순서도 기반의 비주얼 프로그래밍인 RAPTOR를 알고리즘 교육 도구로 제안하였다. 또한 일반계고등학교 학생을 대상으로 5단계에 걸쳐 12차시의 교육을 적용한 결과 RAPTOR를 이용한 알고리즘 교육이 높은 효과가 있음을 확인하였다.

Analysis of Joint Transmit and Receive Antenna Selection in CPM MIMO Systems

  • Lei, Guowei;Liu, Yuanan;Xiao, Xuefang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권3호
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    • pp.1425-1440
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    • 2017
  • In wireless communications, antenna selection (AS) is a widely used method for reducing comparable cost of multiple RF chains in MIMO systems. As is well known, most of literatures on combining AS with MIMO techniques concern linear modulations such as phase shift keying (PSK) and quadrature amplitude modulation (QAM). The combination of CPM and MIMO has been considered an optimal choice that can improve its capacity without loss of power and spectrum efficiency. The aim of this paper is to investigate joint transmit and receive antenna selection (JTRAS) in CPM MIMO systems. Specifically, modified incremental and decremental JTRAS algorithms are proposed to adapt to arbitrary number of selected transmit or receive antennas. The computational complexity of several JTRAS algorithms is analyzed from the perspective of channel capacity. As a comparison, the performances of bit error rate (BER) and spectral efficiency are evaluated via simulations. Moreover, computational complexity of the JTRAS algorithms is simulated in the end. It is inferred from discussions that both incremental JTRAS and decremental JTRAS perform close to optimal JTRAS in BER and spectral efficiency. In the sense of practical scenarios, adaptive JTRAS can be employed to well tradeoff performance and computational complexity.

A Fast Kernel Regression Framework for Video Super-Resolution

  • Yu, Wen-Sen;Wang, Ming-Hui;Chang, Hua-Wen;Chen, Shu-Qing
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제8권1호
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    • pp.232-248
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    • 2014
  • A series of kernel regression (KR) algorithms, such as the classic kernel regression (CKR), the 2- and 3-D steering kernel regression (SKR), have been proposed for image and video super-resolution. In existing KR frameworks, a single algorithm is usually adopted and applied for a whole image/video, regardless of region characteristics. However, their performances and computational efficiencies can differ in regions of different characteristics. To take full advantage of the KR algorithms and avoid their disadvantage, this paper proposes a kernel regression framework for video super-resolution. In this framework, each video frame is first analyzed and divided into three types of regions: flat, non-flat-stationary, and non-flat-moving regions. Then different KR algorithm is selected according to the region type. The CKR and 2-D SKR algorithms are applied to flat and non-flat-stationary regions, respectively. For non-flat-moving regions, this paper proposes a similarity-assisted steering kernel regression (SASKR) algorithm, which can give better performance and higher computational efficiency than the 3-D SKR algorithm. Experimental results demonstrate that the computational efficiency of the proposed framework is greatly improved without apparent degradation in performance.

공간 상관성을 이용한 적응적 움직임 추정 알고리즘 (An Adaptive Motion Estimation Algorithm Using Spatial Correlation)

  • 박상곤;정동석
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2000년도 하계종합학술대회 논문집(4)
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    • pp.43-46
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    • 2000
  • In this paper, we propose a fast adaptive diamond search algorithm(FADS) for block matching motion estimation. Fast motion estimation algorithms reduce the computational complexity by using the UESA (Unimodal Error Search Assumption) that the matching error monotonically increases as the search moves away from the global minimum error. Recently many fast BMAs(Block Matching Algorithms) make use of the fact that the global minimum points in real world video sequences are centered at the position of zero motion. But these BMAs, especially in large motion, are easily trapped into the local minima and result in poor matching accuracy. So, we propose a new motion estimation algorithm using the spatial correlation among the adjacent blocks. We change the origin of search window according to the spatially adjacent motion vectors and their MAE(Mean Absolute Error). The computer simulation shows that the proposed algorithm has almost the same computational complexity with UCBDS(Unrestricted Center-Biased Diamond Search)〔1〕, but enhance PSNR. Moreover, the proposed algorithm gives almost the same PSNR as that of FS(Full Search), even for the large motion case, with half the computational load.

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Algorithm for Improving the Computing Power of Next Generation Wireless Receivers

  • Rizvi, Syed S.
    • Journal of Computing Science and Engineering
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    • 제6권4호
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    • pp.310-319
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    • 2012
  • Next generation wireless receivers demand low computational complexity algorithms with high computing power in order to perform fast signal detections and error estimations. Several signal detection and estimation algorithms have been proposed for next generation wireless receivers which are primarily designed to provide reasonable performance in terms of signal to noise ratio (SNR) and bit error rate (BER). However, none of them have been chosen for direct implementation as they offer high computational complexity with relatively lower computing power. This paper presents a low-complexity power-efficient algorithm that improves the computing power and provides relatively faster signal detection for next generation wireless multiuser receivers. Measurement results of the proposed algorithm are provided and the overall system performance is indicated by BER and the computational complexity. Finally, in order to verify the low-complexity of the proposed algorithm we also present a formal mathematical proof.

다양한 근사인수분해 알고리즘을 이용하여 압축성 유동장의 수렴성 및 유용성에 대한 연구 (A Numerical Study on Efficiency and Convergence for Various Implicit Approximate Factorization Algorithms in Compressible Flow Field.)

  • 권창오;송동주
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 1999년도 추계 학술대회논문집
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    • pp.17-22
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    • 1999
  • Convergence characteristics and efficiency of three implicit approximate factorization schemes(ADI, DDADI and MAF) are examined using 2-Dimensional compressible upwind Navier-Stokes code. Second-order CSCM(Conservative Supra Characteristic Method) upwind flux difference splitting method with Fromm scheme is used for the right-hand side residual evaluation, while generally first-order upwind differencing is used for the implicit operator on the left-hand side. Convergence studies are performed using an example of the flow past a NACA0012 airfoil at steady transonic flow condition, i. e. Mach number 0.8 at $1.25^{\circ}$ angle of attack. The results were compared with other computational results in order to validate the current numerical analysis. The results from the implicit AF algorithms were compared well in low surface with the other computational results; however, not well in upper surface. It might be due to lack of the grid around the shock position. Because the algorithm minimizes the errors of the approximate decomposition, the improved convergence rate with MAF were observed.

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