• 제목/요약/키워드: multi-scale

검색결과 2,275건 처리시간 0.029초

비압축성유동을 위한 수치적응 격자생성에 관한 연구 (A Study on Numerical Adaptive Grid Generation for Incompressible Flow)

  • 이주희;이상환;윤준용
    • 대한기계학회논문집
    • /
    • 제19권9호
    • /
    • pp.2237-2248
    • /
    • 1995
  • In incompressible flow which has multi-length scale, it has a very important effect which dependent variables are used for adaptive grid generation. Among many length scales in incompressible flow, the dependent variables used for the adaptive grid generation should be able to represent the feature of the concerned system. In this paper, by using vorticity and stream function, in addition to velocity components, the smoother and more stable grid generation is possible and these four flow properties represent each scale. The adaptive grid generation for a lid-driven cavity flow with $N_{re}$ =3200 using four flow properties such as velocity components, vorticity, stream function is performed, and the usefulness of using vorticity and stream function as the indicator for adaptive grid generation is shown.

A PROPOSAL OF ENHANSED NEURAL NETWORK CONTROLLERS FOR MULTIPLE CONTROL SYSTEMS

  • Nakagawa, Tomoyuki;Inaba, Masaaki;Sugawara, Ken;Yoshihara, Ikuo;Abe, Kenichi
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 1998년도 제13차 학술회의논문집
    • /
    • pp.201-204
    • /
    • 1998
  • This paper presents a new construction method of candidate controllers using Multi-modal Neural Network(MNN). To improve a control performance of multiple controller, we construct, candidate controllers which consist of MNN. MNN can learn more complicated function than multilayer neural network. MNN consists of preprocessing module and neural network module. The preprocessing module transforms input signals into spectra which are used as input of the following neural network module. We apply the proposed method to multiple control system which controls the cart-pole balancing system and show the effectiveness of the proposed method.

  • PDF

개선된 색상복원을 이용한 멀티스케일 레티넥스 (Multi-Scale Retinex Using Modified Color Restoration Method)

  • 유성재;이준환;이상범
    • 대한전자공학회:학술대회논문집
    • /
    • 대한전자공학회 2006년도 하계종합학술대회
    • /
    • pp.727-728
    • /
    • 2006
  • In this paper, we analyzed the color restoration method to be used in the Multi-Scale Retinex and proposed new color restoration method. and, we compared the result of the algorithm to be proposed with conventional algorithm through the experiment.

  • PDF

다중 스케일 네트워크 기반 영상 내 모아레 무늬 제거 기법 (Image Demorieing Based on a Multi-scale Neural Network)

  • 박현국;비엔지아안;이철
    • 한국방송∙미디어공학회:학술대회논문집
    • /
    • 한국방송∙미디어공학회 2020년도 하계학술대회
    • /
    • pp.263-265
    • /
    • 2020
  • 본 논문에서는 다중 스케일로 구성된 뉴럴 네트워크를 이용하여 영상 내 모아레 무늬을 제거하는 기법을 제안한다. 제안하는 기법은 영상 피라미드를 생성하여 모아레 무늬를 구성하는 다양한 주파수 범위의 정보를 제거한다. 각 branch는 Multi-scale Feature Block (MFB)과 Tone-Mapping Block (TMB)으로 구성하여 효과적으로 모아레 현상을 제거하고 저하된 색상 저하를 복원한다. 컴퓨터 모의실험을 통해 제안하는 기법이 기존 기법에 비해서 높은 모아레 제거 성능을 보이는 것을 확인한다.

  • PDF

다문화 가정 유아들의 함께 주의하기와 언어발달 (Joint Attention and Language Development in Infants from Multi-Cultural Families)

  • 박영신
    • 아동학회지
    • /
    • 제31권6호
    • /
    • pp.35-50
    • /
    • 2010
  • Joint attention, language development, and the relationship between these two variables were compared in infants from multi-cultural and Korean families. Joint attention was observed in both the Early Social Communication Scale (ESCS) and in infant-mother free play. Language development was evaluated by means of the MacArthur-Bates Communicative Development Inventory-Korean. There were no group differences in initiating and responding to joint attention in ESCS. However, in infant-mother free play, joint attention episodes were less and shorter in duration with infants from multi-cultural families than in Korean infants. The size of both the expressive and receptive vocabulary was also smaller in infants from multi-cultural families than in Korean infants. In terms of Korean infants, mean duration of joint attention episodes in free play showed a significant positive correlation with the size of the expressive vocabulary and initiating joint attention in ESCS also showed a significant positive correlation with the size of receptive vocabulary. However, none of the measures of joint attention indicated a significant relationship with the size of either expressive or receptive vocabulary in infants from multi-cultural families.

중전압 계통 연계를 위한 멀티 센트럴 대용량 태양광 발전 시스템의 공통 모드 전압 억제 (Suppression of Common-Mode Voltage in a Multi-Central Large-Scale PV Generation Systems for Medium-Voltage Grid Connection)

  • 배영상;김래영
    • 전력전자학회논문지
    • /
    • 제19권1호
    • /
    • pp.31-40
    • /
    • 2014
  • This paper describes an optimal configuration for multi-central inverters in a medium-voltage (MV) grid, which is suitable for large-scale photovoltaic (PV) power plants. We theoretically analyze a proposed common-mode equivalent model for problems associated with multi-central transformerless-type three-phase full bridge(3-FB) PV inverters employing two-winding MV transformers. We propose a synchronized PWM control strategy to effectively reduce the common-mode voltages that may simultaneously occur. In addition, we propose that the existing 3-FB topology may also have the configuration of a multi-central inverter with a two-winding MV transformer by making a simple circuit modification. Simulation and experimental results of three 350kW PV inverters in a multi-central configuration verify the effectiveness of the proposed synchronization control strategy. The modified transformerless-type 3-FB topology for a multi-central PV inverter configuration is verified using an experimental prototype of a 100kW PV inverter.

Multi-scale modelling of the blood chamber of a left ventricular assist device

  • Kopernik, Magdalena;Milenin, Andrzej
    • Advances in biomechanics and applications
    • /
    • 제1권1호
    • /
    • pp.23-40
    • /
    • 2014
  • This paper examines the blood chamber of a left ventricular assist device (LVAD) under static loading conditions and standard operating temperatures. The LVAD's walls are made of a temperature-sensitive polymer (ChronoFlex C 55D) and are covered with a titanium nitride (TiN) nano-coating (deposited by laser ablation) to improve their haemocompatibility. A loss of cohesion may be observed near the coating-substrate boundary. Therefore, a micro-scale stress-strain analysis of the multilayered blood chamber was conducted with FE (finite element) code. The multi-scale model included a macro-model of the LVAD's blood chamber and a micro-model of the TiN coating. The theories of non-linear elasticity and elasto-plasticity were applied. The formulated problems were solved with a finite element method. The micro-scale problem was solved for a representative volume element (RVE). This micro-model accounted for the residual stress, a material model of the TiN coating, the stress results under loading pressures, the thickness of the TiN coating and the wave parameters of the TiN surface. The numerical results (displacements and strains) were experimentally validated using digital image correlation (DIC) during static blood pressure deformations. The maximum strain and stress were determined at static pressure steps in a macro-scale FE simulation. The strain and stress were also computed at the same loading conditions in a micro-scale FE simulation.

우울과 불안의 변별적 진단을 위한 다차원 정서 척도의 개발 (Development of an Multi-dimentional Affect Scale for Distinguishing between Depression and Anxiety)

  • 이창묵
    • 한국융합학회논문지
    • /
    • 제9권10호
    • /
    • pp.393-406
    • /
    • 2018
  • 우울과 불안은 진단 기준, 관련 이론, 증상 등에서 유사한 점이 많아 기존의 척도로는 서로를 변별하기 어렵다는 문제가 있다. 본 연구에서는 정적 정서와 부적 정서가 우울, 불안과 높은 관련성을 가지고 있다는 선행 연구를 근거로 우울과 불안의 변별적 진단을 목적으로 하는 진단 척도를 개발하였다. 먼저 우울과 불안의 공통분을 제거한 편상관 계수를 기준으로, 한 쪽에만 높은 상관을 나타내는 문항들을 찾아서 우울 및 불안에 대한 씨앗 척도를 구성하였다. 이 두 씨앗 척도를 독립변수로, 각 정서 문항을 종속변수로 하는 다중 회귀를 시행하여 회귀 계수를 구했으며, 이것을 우울과 불안 점수의 배점으로 사용하였다. 이렇게 개발된 정서 척도는 좋은 내적 일치도를 나타냈으며, 기존 척도와는 높은 상관을 가지면서도 서로에 대한 상관은 더 낮았기 때문에, 기존 척도만큼 잘 측정하면서도 우울과 불안을 좀 더 잘 변별할 것으로 기대되었다. 실제 활용을 위해서 정서에 대한 문화적 특성을 보완하고, 보다 정교한 통계적 방법을 적용해야 할 것이며, 임상집단을 대상으로 하는 타당화 연구를 제안하였다.