• 제목/요약/키워드: integral distribution

검색결과 427건 처리시간 0.022초

Stochastic ship roll motion via path integral method

  • Cottone, G.;Paola, M. Di;Ibrahim, R.;Pirrotta, A.;Santoro, R.
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • 제2권3호
    • /
    • pp.119-126
    • /
    • 2010
  • The response of ship roll oscillation under random ice impulsive loads modeled by Poisson arrival process is very important in studying the safety of ships navigation in cold regions. Under both external and parametric random excitations the evolution of the probability density function of roll motion is evaluated using the path integral (PI) approach. The PI method relies on the Chapman-Kolmogorov equation, which governs the response transition probability density functions at two close intervals of time. Once the response probability density function at an early close time is specified, its value at later close time can be evaluated. The PI method is first demonstrated via simple dynamical models and then applied for ship roll dynamics under random impulsive white noise excitation.

유수정리를 이용한 마이크로스트립 선로의 스펙트럼 영역 해석 (A spectral domain analysis of microstrip lines using a residue theorem)

  • 문병귀;진경수;박병우
    • 전자공학회논문지D
    • /
    • 제35D권1호
    • /
    • pp.8-15
    • /
    • 1998
  • An analysis of the microstripline is started as an assumption of the axial & transveral current distribution. Applying the boundary conditions to the scalar wave equations of a electric & magnetic potential, the two simultaneous coupled integral equations are produced. The electronmagnetic fields in microstrip line can be obtained by solving these two coupled integral equaltion. In general, either a numerical analysis method or a Galerkin method was used to solve them. In this paper, a residue theorem is proposed to solve them. The electromagnetic fields are expressed as integral equations for LSE and LSM mode in the spectral domain. Applying a residue theorem to the Fourier transformed equation and Fourier inverse transformed equation which is necessary for interchanging the space domain and the spectral domain, the electromagnetic fields are expressed as algebraic equations whichare relatively easier to handle. the distributions of the electromagnetic field are shown at the range of -5w/2.leq.x.leq.5w/2, 0.lep.y.leq.4h for z=0. It agrees well with the results of the Quasi-TEM mode analysis.

  • PDF

이종금속 오버레이 용접 배관의 파단전누설균열 해석을 위한 단순 유한요소 모델링 방법 (A Simple Finite Element Modeling Method for Leak-Before-Break Crack Analysis of Pipe with Overlay Dissimilar Metal Weldments)

  • 김만원;박영섭
    • 한국압력기기공학회 논문집
    • /
    • 제9권1호
    • /
    • pp.70-76
    • /
    • 2013
  • Several finite element models for the leak-before-break (LBB) assessment of overlay dissimilar metal weldment were constructed and analyzed to develop a simple finite element modeling method. The J-integral, crack opening displacement (COD) and J-integral distribution along the crack front in thickness direction due to the applied moment were obtained from the analysis results of the constructed finite element models, and studied compared to the previous literatures. It is concluded that the modeling with base material only is simple and produces a slightly conservative results compared to the complex modeling composed with weld metal and base metal in the calculation of J-integrals and COD values which are used for the calculation of fracture toughness and postulated leakage crack length respectively.

3차원 적분법을 이용한 변류기의 누설 자계 및 누설 인덕턴스 해석 (Analyses of Leakage Magnetic Field and Leakage Inductance in Current Transformers by 3-D Integral Methods)

  • 이희갑;박용필;이준웅;박우현;이기식
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
    • /
    • pp.503-506
    • /
    • 2001
  • This paper presents leakage magnetic field and leakage inductance calculations in current transformer by means of 3-D Integral methods. From the distribution diagram of leakage magnetic flux to be analyzed using program called TRACAL3, it confirms a parallel to the winding axis direction of the leakage flux lines in the air gap between the windings. The leakage inductances L$\sub$r1/ and L$\sub$R2/ of the primary and secondary windings were calculated, their values are 4.23 mH and 0.49 mH, respectively. They are also similar to the measured values of the leakage inductances for the experimental verification, 4.06 mH and 0.47 mH.

  • PDF

Uncovering galaxy individuality with multiplexed integral field spectroscopy.

  • Croom, Scott;Bryant, Julia
    • 천문학회보
    • /
    • 제42권1호
    • /
    • pp.27.1-27.1
    • /
    • 2017
  • There is a rich diversity of galaxy properties and we are starting to understand some of the drivers for differences between galaxies. Much progress has been has been made in the last decade, thanks in large part to massively multiplexed surveys using single fibres, but we still lack a complete picture of how galaxies are built. I will discuss how large-scale integral field surveys can address a number of the outstanding questions in the field, starting with the current SAMI Galaxy Survey, and then looking towards the Hector instrument that will carry out integral field surveys of order 50,000-100,000 galaxies. With SAMI we can start to address how mass and environment influence galaxy structure and history, and I will discuss examples such as the environmental quenching of star formation and the distribution of angular momentum. With larger samples afforded by Hector we can go beyond simply mass and environment, to separate galaxies based on their merger or accretion history, as well as their larger-scale environment.

  • PDF

제한된 범위의 역산란 포텐셜을 갖는 Gel'fand-Levitan-Marchenko 적분방정식의 해와 유전율 분포 합성에의 응용 (Solution of Gel'fand-Levitan-Marchenko Integral Equation with Restricted Inverse Scattering Potential and Its Applications to Synthesis of Dielectric Constant Distribution)

  • 장완규;정현수;박의준
    • 한국전자파학회:학술대회논문집
    • /
    • 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
    • /
    • pp.54-58
    • /
    • 2003
  • In this study, the solution of Gel'fand-Levitan-Marchenko integral equation in the inverse scattering problem is efficiently solved for arbitrarily specified spectra pattern which are reflected from the restricted potential. The procedure is based on the successive approach without iterations. This method lessens the truncation errors which plague conventional design schemes using specific windows for reflection coefficients. It is shown that the method is adequate for the synthesis of the continuously varying one-dimensional potential of the nonuniformly distributed dielectric constants.

  • PDF

일체형원자로 증기발생기 카세트 하단에 설치된 오리피스의 최적설계 연구 (A numerical study on the optimum size for the orifice located on the steam generator cassette of integral reactor)

  • 강형석;윤주현;김환열;조봉현;이두정
    • 한국전산유체공학회:학술대회논문집
    • /
    • 한국전산유체공학회 1998년도 춘계 학술대회논문집
    • /
    • pp.75-81
    • /
    • 1998
  • A new advanced integral reactor of 330 MWt capacity named SMART(System-integrated Modular Advanced ReacTor) is currently under development at KAERI(Korea Atomic Energy Research Institute). One of the major design features of the integral reactor is locating the steam generators(SG) inside reactor vessel and eliminating the possibility of LB LOCA(large Break Loss of Coolant Accident). Orifices are fitted at the low part of steam generator cassette to stabilize and balance coolant flow distribution in the MCP (Main Circulation Pump) pressure header. A sensitivity analysis is conducted to determine the optimum orifice size using computer code 'CFX'.

  • PDF

3차원 적분법을 이용한 변류기의 자계해석과 누설 인덕턴스에 대한 연구 (A Study on the Magnetic Field Analysis and Leakage Inductance in Current Transformers by 3D Integral Methods)

  • 이희갑;박용필
    • 한국전기전자재료학회논문지
    • /
    • 제14권9호
    • /
    • pp.768-772
    • /
    • 2001
  • This paper presents leakage magnetic field and leakage inductance calculations in current transformer by means of 3-D Integral methods. From the distribution diagram of leakage magnetic flux to be analyzed using program called TRACAL 3, ti confirms a parallel to the winding axis direction of the leakage flux lines in the air gap between the windings. The leakage inductances L$\sub$r1/ and L$\sub$r2/ of the primary and secondary winding were calculated, their values are 4.23 MH and 0.49 mH, respectively. They are also similar to the measured values of he leakage inductances of the experimental verification, 4.06 mH and 0.47 mH.

  • PDF

간접경계적분법을 이용한 변압기 cover plate에서의 와전류 해석 (Eddy Current Analysis In Cover Plate of Power Transformers using Indirect Boundary Integral Equation Method)

  • 김상영;김동훈;한송엽
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
    • /
    • pp.88-90
    • /
    • 1998
  • In this paper, the indirect BIEM(boundary integral equation method) is adopted to analyze 3-D eddy currents in cover plate of power transformer. In indirect BIEM, the equivalent magnetic surface charge density and the eqivalent magnanetic surface current density are the unknowns. Using triangular constant elements, the integral equations are discretized into boundary element equations of minimum order. Eddy currents are obtained in terms of euqivalent magnetic surface sources. And the locad overheating can be predicted using the eddy currents distribution in cover plate of power transformer.

  • PDF