• Title/Summary/Keyword: 수렴률

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An Empirical Study on the Effect of Local Festivals on Economic Growth (지역 축제의 경제성장 효과에 관한 실증분석)

  • Kim, Youngduk
    • Journal of the Korean Data Analysis Society
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    • v.20 no.6
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    • pp.2981-2991
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    • 2018
  • The purpose of this paper is to examine the effect of local festivals on regional economic growth through empirical analysis of festival - economic growth relation. Theoretically, the theory of creative city is at the center of the discussion as to how festivals can influence economic growth. We used the regional convergence equation and used pooled OLS, fixed effect model, and GMM estimation method to analyze the effect of festivals on regional economic growth. According to this empirical analysis, the effect of festival variables such as the number of festivals and the festival period on economic growth has not been affected. This suggests that the effects of festivals on productivity and efficiency have not existed. This implies that the creative city theory that local festivals influence regional economic growth does not work well.

An Analysis of Poisson's Ratio Behaviors by Uniaxial Compressive Loading-reloading Test - On the Sedimentary Rocks of Kyungsang Basin - (일축압축 하에서 반복재하에 따른 포아송비의 거동분석 - 경상분지 퇴적암을 대상으로 -)

  • Lee, Jong-Suok;Moon, Jong-Kyu;Choi, Woong-Eui
    • Tunnel and Underground Space
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    • v.23 no.1
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    • pp.66-77
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    • 2013
  • This paper deals with Poisson's ratio and volumetric strain behavior on loading-reloading terms under uniaxial condition targeting 404 individual rocks, which include sedimentary rocks as sandstone, shale, mudstone, conglomerate and tuff on Kyungsang basin. Poisson' ratio demonstrates increase, convergence and decrease behavior according to the increase in load, which results in preponderance of increase behavior. Volumetric strain demonstrates normal, positive and negative behavior according to the increase in load, which results in preponderance of normal behavior. On practice, Poisson's ratio can be indicative of high or low values with low values of design load. Consequently, a careful selection of results in in-situ sample experiment should be made and varying design conditions should be considered.

Review of control parameter of SCE-UA (SCE-UA기법의 제어 매개변수 검토)

  • Taehun Jung;Sangho Lee;Namjoo Lee
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.350-350
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    • 2023
  • SCE-UA(Shuffled Complex Evolution-University Arizona)기법은 최적해 탐색 알고리즘으로 개념적 강우유출 모형(conceptual rainfall runoff model)의 보정을 위한 도구로 개발되었다. SCE-UA기법은 메타휴리스틱 방법의 일종으로 최적해를 구하기 위하여 여러번 목적함수 값을 계산해야 한다. 이 때 목적함수 계산 횟수와 해의 수렴과 관련된 제어 매개변수가 존재하며, 사용자가 적절한 값을 입력해주어야 한다. 이 연구에서는 SCE-UA와 관련된 제어 매개변수의 기능에 대해서 검토하였다. 그리고 집합체 수의 변화에 따라서 검사함수인 Ackley function의 전역해를 얼마나 잘 탐색하는지 검토하였다. 검토 결과 랜덤 시드에 따라서 전역해 탐색 결과가 달라졌으며, 집합체의 수가 증가할수록 목적함수 계산 횟수는 증가하는 경향을 나타내었다. 검사함수의 차원(결정 변수의 수)이 증가하면 전역해의 탐색률이 감소하며, 집합체의 수가 많아지면 전역해를 더 잘 찾는 경향이 나타나지만, 목적함수 계산 횟수는 더 많아지게 되는 것을 확인할 수 있었다. 2차원인 경우 집합체의 수가 7개 이상일 때 탐색 성공률은 90% 이상이 되었지만, 10차원인 경우 집합체의 수가 시험 최대값인 20개일 때의 전역해 탐색률은 37%에 그쳤다. 이 연구의 결과는 SCE-UA 기법의 설정 매개변수에 관한 기본 개념을 이해하고, 사용자가 설정 매개변수 선정 시에 활용할 수 있을 것이다.

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Improvement of Enhanced Assumed Strain Four-node Finite Element Based on Reissner-Mindlin Plate Theory (개선된 추가변형률 4절점 평판휨 요소)

  • Chun, Kyoung Sik;Park, Dae Yong;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
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    • v.16 no.3 s.70
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    • pp.295-303
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    • 2004
  • In this paper, an improved four-node Reissner-Mindlin plate-bending element with enhanced assumed strain field is presented for the analysis of isotropic and laminated composite plates. To avoid the shear locking and spurious zero energy modes, the transverse shear behavior is improved by the addition of a new enhanced shear strain based on the incompatible displacement mode approach and bubble function. The "standard" enhanced strain fields (Andelfinger and Ramm, 1993) are also employed to improve the in-plane behaviors of the plate elements. The four-node quadrilateral element derived using the first-order shear deformation theory is designated as "14EASP". Several applications are investigated to assess the features and the performances of the proposed element. The results are compared with other finite element solutions and analytical solutions. Numerical examples show that the element is stable, invariant, passes the patch test, and yields good results especially in highly distorted regimes.

Shear Strain Big-Bang of RC Membrane Panel Subjected to Shear (순수전단이 작용하는 RC막판넬의 전단변형률 증폭)

  • Jeong, Je Pyong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.1
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    • pp.101-110
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    • 2015
  • Recently, nine $1397{\times}1397{\times}178mm$ RC panels were tested under in-plane pure-shear monotonic loading condition using the Panel Element Tester by Hsu (1997, ACI). By combining the equilibrium, compatibility, and the softened stress-strain relationship of concrete in biaxial state, Modern Truss Model (MCFT, RA-STM) are capable of producing the nonlinear analysis of RC membrane panel through the complicated trial-and-error method with double loop. In this paper, an efficient algorithm with one loop is proposed for the refined Mohr compatibility Method based on the strut-tie failure criteria. This algorithm can be speedy calculated to analyze the shear history of RC membrane element using the results of Hsu test. The results indicate that the response of shear deformation energy at Big Bang of shear strain significantly influenced by the principal compressive stress-strain (crushing failure).

Strain-rate-dependent Consolidation Characteristics of Busan Clay (부산점토의 변형률 속도 의존적인 압밀특성)

  • Kim Yun-Tae;Jo Sang-Chan;Jo Gi-Young
    • Journal of the Korean Geotechnical Society
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    • v.21 no.6
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    • pp.127-135
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    • 2005
  • In order to analyze effects of strain rate on consolidation characteristics of Busan clay, a series of constant rate of strain (CRS) consolidation tests with different strain rate and incremental loading tests (ILT) were performed. From experimental test results on Busan clay, it was found that the preconsolidation pressure was dependent on the corresponding strain rate occurring during consolidation process. Also, consolidation curves normalized with respect to preconsolidation pressure gave a unique stress-strain curve. Coefficient of consolidation and permeability estimated from CRS test had a tendency to converge to a certain value at normally consolidated range regardless of strain rate. An increase in excess pore pressure was observed after the end of loading without change of total stress on the incremental loading test, which phenomenon is called Mandel-Cryer effect. It was also found that rapid generation of excess pore pressure took place due to collapse of soil structure as effective stress approached to preconsolidation pressure.

Learning Ability of Deterministic Boltzmann Machine with Non-Monotonic Neurons in Hidden Layer (은닉층에 비단조 뉴런을 갖는 결정론적 볼츠만 머신의 학습능력에 관한 연구)

  • 박철영
    • Journal of the Korean Institute of Intelligent Systems
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    • v.11 no.6
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    • pp.505-509
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    • 2001
  • In this paper, we evaluate the learning ability of non-monotonic DMM(Deterministic Boltzmann Machine) network through numerical simulations. The simulation results show that the proposed system has higher performance than monotonic DBM network model. Non-monotonic DBM network also show an interesting result that network itself adjusts the number of hidden layer neurons. DBM network can be realized with fewer components than other neural network models. These results enhance the utilization of non-monotonic neurons in the large scale integration of neuro-chips.

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A Study On The Parameter Selection of ($1+{\lambda}$) Evolution Strategy (($1+{\lambda}$)진화 전략 알고리즘의 파라미터 선정에 대한 연구)

  • Park, Sang-Hun;An, Kwang-Ok;Cho, Sung-Mun;Cho, Dong-Hyeok;Jung, Hyun-Kyo
    • Proceedings of the KIEE Conference
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    • 2001.04a
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    • pp.75-77
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    • 2001
  • 전기기기 최적 설계에 있어서 결정론적 최적화 방법은 국부해를 빠른 속도로 찾을 수 있지만 최적값에 대한 보장이 어려우므로 비결정론적 방법인 진화전략 알고리즘을 많이 사용한다. 전기기기 최적화에 쓰이는 많은 확률적 알고리즘 중에서 진화 전략 알고리즘은 시뮬레이티드 어닐링과 유전 알고리즘을 결합한 방법으로, 전체 최적점 탐색이 가능할 뿐만 아니라 알고리즘이 비교적 간단하면서도 빠른 수렴 특성을 갖고 있다. 그리고, 종류 또한 다양하다. 진화 전략 알고리즘 중에서 중요한 것은 수렴속도와 성공률에 기여하는 파라미터들을 잘 선정하는 것이다. 본 논문에서는, 진화 전략 알고리즘의 중요한 인자인 자식 세대의 개수인 ${\lambda}$값과 ${\alpha}$값을 변화시켜 가면서 변수 개수에 따른 최적화된 조합을 제시한다. 본 논문의 결과는 전기기기 최적 설계에 응용하는데 도움이 될 것으로 사료된다.

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On the Enhancement of the Recognition Performance for Back Propagation Neural Networks (역전파 선경회로망의 인식성능 향상에 관한 연구)

  • 홍봉화;이지영
    • Journal of the Korea Society of Computer and Information
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    • v.4 no.4
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    • pp.86-93
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    • 1999
  • This paper proposes the multi-modular neural network and compensative input algorithm. The former is to reduce convergence speed which is one of the neural network's inveterate problems, and the latter is to improve the recognition performance of the neural network. This paper consists of two major parts and a simulation. First, it shows the structure of mu1ti-modular neural network, which is applied to the recognition of Korean, English characters and numbers. Second, it describes the compensative input algorithm and shows the steps that determine the compensative input. The proposed algorithm was tested and compared with the existing neural networks in the recognition of Korean and English characters and numbers. The convergence speed is three times or more faster than the existing neural network. In the case that compensative input was applied to neural network, the recognition rate was improved more than 10%.

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Vibration Analysis of a Turbo-Machinery Blade Considering Rotating and Flow Effect (회전 및 유동효과를 고려한 터보기계 블레이드의 진동해석)

  • Joung, Kyu-Kang;Shin, Seung-Hoon;Park, Hee-Yong;Kim, Dong-Hyun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.519-522
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    • 2010
  • Flow-induced vibration analyses have been conducted for a 3D compressor blade model. Advanced computational analysis system based on computational fluid dynamics(CFD) and computational structural dynamics has been developed in order to investigate detailed dynamic responses of designed compressor blades. A fully implicit time marching scheme based on the Newmark direct integration method is used for computing the coupled aeroelastic governing equations of the 3D compressor blade for fluid-structure interaction problems. Detailed dynamic responses and instantaneous pressure contours on the blade surfaces considering flow-separation effects are presented to show the multi-physical phenomenon of the rotating compressor blade.

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