• 제목/요약/키워드: Time Complexity

검색결과 3,062건 처리시간 0.033초

대용량 악성코드의 특징 추출 가속화를 위한 분산 처리 시스템 설계 및 구현 (Distributed Processing System Design and Implementation for Feature Extraction from Large-Scale Malicious Code)

  • 이현종;어성율;황두성
    • 정보처리학회논문지:컴퓨터 및 통신 시스템
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    • 제8권2호
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    • pp.35-40
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    • 2019
  • 기존 악성코드 탐지는 다형성 또는 난독화 기법이 적용된 변종 악성코드 탐지에 취약하다. 기계학습 알고리즘은 악성코드에 내재된 패턴을 학습시켜 유사 행위 탐지가 가능해 기존 탐지 방법을 대체할 수 있다. 시간에 따라 변화하는 악성코드 패턴을 학습시키기 위해 지속적으로 데이터를 수집해야한다. 그러나 대용량 악성코드 파일의 저장 및 처리 과정은 높은 공간과 시간 복잡도가 수반된다. 이 논문에서는 공간 복잡도를 완화하고 처리 시간을 가속화하기 위해 HDFS 기반 분산 처리 시스템을 설계한다. 분산 처리 시스템을 이용해 2-gram 특징과 필터링 기준에 따른 API 특징 2개, APICFG 특징을 추출하고 앙상블 학습 모델의 일반화 성능을 비교했다. 실험 결과로 특징 추출의 시간 복잡도는 컴퓨터 한 대의 처리 시간과 비교했을 때 약 3.75배 속도가 개선되었으며, 공간 복잡도는 약 5배의 효율성을 보였다. 특징 별 분류 성능을 비교했을 때 2-gram 특징이 가장 우수했으나 훈련 데이터 차원이 높아 학습 시간이 오래 소요되었다.

시각물체 추적 시스템을 위한 멀티코어 프로세서 기반 태스크 스케줄링 방법 (A Task Scheduling Strategy in a Multi-core Processor for Visual Object Tracking Systems)

  • 이민채;장철훈;선우명호
    • 한국자동차공학회논문집
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    • 제24권2호
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    • pp.127-136
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    • 2016
  • The camera based object detection systems should satisfy the recognition performance as well as real-time constraints. Particularly, in safety-critical systems such as Autonomous Emergency Braking (AEB), the real-time constraints significantly affects the system performance. Recently, multi-core processors and system-on-chip technologies are widely used to accelerate the object detection algorithm by distributing computational loads. However, due to the advanced hardware, the complexity of system architecture is increased even though additional hardwares improve the real-time performance. The increased complexity also cause difficulty in migration of existing algorithms and development of new algorithms. In this paper, to improve real-time performance and design complexity, a task scheduling strategy is proposed for visual object tracking systems. The real-time performance of the vision algorithm is increased by applying pipelining to task scheduling in a multi-core processor. Finally, the proposed task scheduling algorithm is applied to crosswalk detection and tracking system to prove the effectiveness of the proposed strategy.

디지털 펄스압축기의 연산 양 비교 (Comparison of Computation Complexity for Digital Pulse Compressor)

  • 신현익;김상규;조태훈;김환우
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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    • pp.2196-2199
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    • 2003
  • With the development of digital signal processor(DSP), digital pulse compressor (DPC) is commonly used in radar systems. A DPC is implemented by using finite impulse response(FIR) filter algorithm in time domain or fast Fourier transform(FFT) algorithm in frequency domain. This paper compares the computation complexity tot these two methods and calculates boundary Fm filter taps that determine which of the two methods is better based on computation amount. Also, it shows that the boundary FIR filter taps for DSP, ADSP21060, and those for computation complexity have similar characteristic.

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On the Signal Power Normalization Approach to the Escalator Adaptive filter Algorithms

  • Kim Nam-Yong
    • 한국통신학회논문지
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    • 제31권8C호
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    • pp.801-805
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    • 2006
  • A normalization approach to coefficient adaptation in the escalator(ESC) filter structure that conventionally employs least mean square(LMS) algorithm is introduced. Using Taylor's expansion of the local error signal, a normalized form of the ESC-LMS algorithm is derived. Compared with the computational complexity of the conventional ESC-LMS algorithm employs input power estimation for time-varying convergence coefficient using a single-pole low-pass filter, the computational complexity of the proposed method can be reduced by 50% without performance degradation.

심플렉스 기법의 복잡성에 관한 연구 (A Study on the Complexity of the Simplex Method)

  • 정성진
    • 한국국방경영분석학회지
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    • 제9권2호
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    • pp.57-60
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    • 1983
  • We show that the complexity of Simplex Method for Linear Programming problem is equivalent to the complexity of finding just an adjacent basic feasible solution if exists. Therefore a simplex type method which resolves degeneracy in polynomial time with respect to the size of the given linear programming problem can solve the general linear programming problem in polynomial steps.

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짝수 홀수 분해법에 기초한 CCI의 효율적인 변형 (Efficient Modifications of Cubic Convolution Interpolation Based on Even-Odd Decomposition)

  • 조현지;유훈
    • 전기학회논문지
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    • 제63권5호
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    • pp.690-695
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    • 2014
  • This paper presents a modified CCI image interpolation method based on the even-odd decomposition (EOD). The CCI method is a well-known technique to interpolate images. Although the method provides better image quality than the linear interpolation, its complexity still is a problem. To remedy the problem, this paper introduces analysis on the EOD decomposition of CCI and then proposes a reduced CCI interpolation in terms of complexity, providing better image quality in terms of PSNR. To evaluate the proposed method, we conduct experiments and complexity comparison. The results indicate that our method do not only outperforms the existing methods by up to 43% in terms of MSE but also requires low-complexity with 37% less computing time than the CCI method.

PROJECT COMPLEXITY AS A MODERATOR OF PERFORMANCE BIAS TOWARDS OVERRUN

  • Li liu;Andrew Nguyen;James Arvanitakis
    • 국제학술발표논문집
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    • The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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    • pp.38-45
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    • 2011
  • Studies have shown that infrastructure projects have continued to experience significant delays and cost overrun over an extended period of time and no evidence of learning ever have happened [1] [2]. Various causes contribute to the bias towards overrun [3]. This study contributes to literature by developing and subsequently validating a set of hypothesized relationships between project complexity and project performance. The results show that project complexity is associated with both the magnitude and variance of overrun. Further, the extent and magnitude of the positive bias towards overrun are moderated by project complexity.

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Feasibility Test and Scheduling Algorithm for Dynamically Created Preemptable Real-Time Tasks

  • Kim, Yong-Seok
    • Journal of Electrical Engineering and information Science
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    • 제3권3호
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    • pp.396-401
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    • 1998
  • An optimal algorithm is presented for feasibility test and scheduling of real-time tasks where tasks are preemptable and created dynamically. Each task has an arbitrary creation time, ready time, maximum execution time, and deadline. Feasibility test and scheduling are conducted via the same algorithm. Time complexity of the algorithm is O(n) for each newly created task where n is the number of tasks. This result improves the previous result of O(n log n). It is shown that the algorithm can be used for scheduling tasks with different levels of importance. Time complexity of the algorithm for the problem is O(n\ulcorner) which improves the previous results of O(n\ulcorner log n).

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SAMDF를 이용한 IMBE VOCODER의 피치 검색 시간 단축에 관한 연구 (On a Reduction of Pitch Search Time for IMBE Vocoder by Using the Spectral AMDF)

  • 홍성훈
    • 한국음향학회:학술대회논문집
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    • 한국음향학회 1998년도 학술발표대회 논문집 제17권 1호
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    • pp.155-158
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    • 1998
  • IMBE(Improved Multi-Band Excitation) vocoders exhibit good performance at low data rates. The major drawback to IMBE coders is their large computational requirements. In this paper, thus, we propose a new pitch search method that preserves the quality of the IMBE vocoder with reduced complexity. The basic idea is to reduce computation complexity of the pitch searching by using the SAMDF. Applying the proposed method to the IMBE vocoder, we can get approximately 52.02% searching time reduction in the pitch search. There is no difference in voice quality between conventional IMBE and proposed IMBE.

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Computational Complexity Comparison of Second-Order Volterrra Filtering Algorithms

  • Im, Sungin
    • The Journal of the Acoustical Society of Korea
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    • 제16권2E호
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    • pp.38-46
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    • 1997
  • The objective of the paper is to compare the computational complexity of five algorithms for computing time-domain second-order Volterra filter outputs in terms of number of real multiplication and addition operations required for implementation. This study shows that if the filter memory length is greater that or equal to 16, the fast algorithm using the overlap-save method and the frequency-domain symmetry properties of the quadratic coefficients is the most efficient among the algorithms investigated in this paper, When the filter memory length is less than 16, the algorithm using the time-domain symmetry properties is better than any other algorithm.

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