• Title/Summary/Keyword: 점근 해석

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Asymptotic Analysis for Hydraulic Fractures and Applicability of Boundary Collocation Method (수압파쇄균열의 점근적 해석과 경계병치법의 적용성)

  • Sim Young-Jong;kim Hong-Ta다
    • Journal of the Korean Geotechnical Society
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    • v.21 no.6
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    • pp.93-100
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    • 2005
  • The occurrence of multi-segmented hydraulic fractures that show different behavior from the single fracture is common phenomenon. However, it is not easy to evaluate the behavior of multiple fractures computed by most numerical techniques because of complicated process computation. This study presents how to efficiently calculate the displacement of the multi-segmented hydraulic fractures using the boundary collocation method (BCM). First of all, asymptotic solutions are obtained for the closely spaced overlapping fractures and are compared with those by the BCM where the number of collocation points is varied. As a result, the BCM provides an excellent agreement with the asymptotic solutions even when the number of collocation points is reduced ten times as many as that of conventional implementations. Accordingly, the numerical simulation of more realistic and, hence, more complex fracture geometries by the BCM would be valid with such a significant reduction of the number of collocation points.

Analytical Solution for Harbour Oscillations (항내응답에 대한 해석해)

  • 서승남
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.8 no.1
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    • pp.72-80
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    • 1996
  • Two analytical solutions for oscillations in a rectangular harbour are presented. In this paper, the correct solution is obtained by use of matched asymptotic expansion method, which was first derived by Mei(1989). The other solution derived from eigenfunction expansion method is also presented, in which more accurate numerical integration is employed. In order to check the solutions, amplification factors inside the harbor are calculated and plotted by both analytical methods and numerical boundary integral equation method.

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Ayymptotic performance analysis and adaptive control of large scale limited service token-passing networks with priorities (우선순위 및 제한 서어비스를 갖는 대규모 토큰-패싱 네트워크의 점근적 성능해석 및 적응제어)

  • 심광현;임종태
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.1000-1005
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    • 1993
  • In this paper asymptotic formulate for performance characteristics throughput, delay) of large scale token-passing networks with priorities and limited service are given. In particular, adaptive control procedures for obtaining optimal buffer capacity with respect to each priority and optimal limited service are shown. All results obtained are supported by simulations.

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Asymptotic performance analysis of closed serial production systems (패쇄직렬 생산시스템의 점근적 성능해석)

  • 임종태
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.519-522
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    • 1990
  • This paper formulates a problem of analysis and design of serial production lines, closed with respect to the number of carriers available in the system for parts transportation between operations. For two machines - two buffers systems, the paper gives an asymptotic solution and shows that optimization of the system with respect to the number of carriers available and the capacity of the feedback buffer may lead to substantial improvements of system's performance.

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On Asymptotic Analysis of the MUSIC Null-Spectrum (MUSIC Null-Spectrum의 점근적 해석)

  • 윤진선;김상엽;김선용;박성일;손재철;송익호;최진호
    • Proceedings of the Korean Institute of Communication Sciences Conference
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    • 1991.10a
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    • pp.115-118
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    • 1991
  • In this paper we derived the asymptotic distribution of the MUSIC null-spectrum, from which an exact expression of the asymptotic variance of the MUSIC null-spectrum can be obtained. From this result in addition an explicit expression of the normalized standard deviation (NSD) has been derived and it is shown that the NSD is affected by the number of sensors and the number of signals.

Analysis on Size-Interval Based Dispatching System for Multi-Class Job Model (Multi-Class Job 모델을 위한 Size-Interval 기반 할당 시스템 분석)

  • Moon, Yong-Hyuk;Kwon, Hyeok-Chan;Youn, Chan-Hyun
    • Proceedings of the Korea Information Processing Society Conference
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    • 2011.04a
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    • pp.163-164
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    • 2011
  • 본고에서는 Multi-class Jobs을 Dispatching system 에서 처리하는 경우, Cost performance 을 점근적으로 해석하는 과정에 대해 논의한다. 구체적으로, Job 할당 시스템은 Size-Interval 기반의 스케줄링 기법을 이용하고, Resource failure 에 대비하여 Job duplication 전략을 활용하는 것으로 가정 한다.

On the Surge Motion of a Ship in Rectangular Harbor (항만내 계류선박의 수평운동 해석)

  • 최항순;조일형
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.1 no.1
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    • pp.81-86
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    • 1989
  • Herein the surge-heave-pitch motion of a ship has been analyzed within the framework of linear potential theory. The ship is assumed slender weakly moored along the centerline of a rectangular harbor with constant depth and straight coastline. The method of matched asymptotic expansion is us-ed to obtain the leading-order solution. The ship and harbor responses to incident long waves can be re-presented in terms of Green's function, which is the solution of the Helmholtz equation satisfying necessary boundary conditions. Numerical results clearly indicate the importance of the surge motion.

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Stability Analysis of Induction Motor by Lyapunov Function Construction of Matrix Polynominal Type (행렬다항식 LYAPUNOV함수 구성에 의한 유도전동기의 안전도 해석)

  • 윤병도;우정인;이준탁
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.2 no.4
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    • pp.62-69
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    • 1988
  • 선형 시스템에 대한 Lyapunov 함수의 구성법은 잘 알려져 있으나, 비선형 시스템의 Lyapunov 함수 구성법은 아직 체계화되어 있지 못하다. 따라서, 본 논문에서는, 비선형 시스템의 안전도 해석을 위하여, 종래의 정상상태 부근에서 Taylor 전개에 의한 선형화 기법에 의존하지 않고, 비선형 시스템을 나타내는 상태공간의 활동성 모델로부터, 비선형성을 나타내는 항을 분리하여, 특수행렬변환시킴으로서, 선형 시스템의 Lyapunov 함수 구성법을 살린, 행렬다항식형 Lyapunov 함수를 구성하고, 이를 유도전동기의 안전도 해석에 적용시켰다. 그 결과, 구해진 안정영역은, 선형화에 의한 것보다는 훨씬 넓은 초공간으로 표현되는 유도전동기의 점근안정영역이 되었다.

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Understanding the Asymptotic Convergence of Domain of Attraction in Extreme Value Distribution for Establishing Baseline Distribution in Statistical Damage Assessment of a Structure (통계적 구조물 손상진단에서 기저분포 구성을 위한 극치분포의 점근적 수렴성 이해)

  • Kang, Joo-Sung;Park, Hyun-Woo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.2 s.54
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    • pp.231-242
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    • 2009
  • The baseline distribution of a structure represents the statistical distribution of dynamic response feature from the healthy state of the structure. Generally, damage-sensitive dynamic response feature of a structure manifest themselves near the tail of a baseline statistical distribution. In this regard, some researchers have paid attention to extreme value distribution for modeling the tail of a baseline distribution. However, few researches have been conducted to theoretically understand the extreme value distribution from a perspective of statistical damage assessment. This study investigates the asymptotic convergence of domain of attraction in extreme value distribution through parameter estimation, which is needed for reliable statistical damage assessment. In particular, the asymptotic convergence of a domain of attraction is quantified with respect to the sample size out of which each extreme value is extracted. The effect of the sample size on false positive alarms in statistical damage assessment is quantitatively investigated as well. The validity of the proposed method is demonstrated through numerically simulated acceleration data on a two span continuous truss bridge.