• Title/Summary/Keyword: integral distribution

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Acoustic Radiation from Radial Vibration Modes of a Thick Annular Disk (후판 환형 디스크 래디얼 모드에 의한 음향방사에 관한 연구)

  • Lee, Hyeongill
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.4 s.97
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    • pp.412-420
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    • 2005
  • This article proposes analytical solutions for sound radiation from radial vibration modes of a thick annular disk. Structural eigensolutions are calculated using the transfer matrix method. The far-field sound pressure distribution is obtained using two alternate methods. In the first method, pressure is calculated using the Rayleigh integral technique. The second method treats sound radiating radial surfaces as cylindrical radiators of finite length. The Sinc function approach is employed for calculations. Acoustic powers and radiation efficiencies of radial modes are also determined from the far-field sound pressure calculations. Analytical predictions match well with measured data as well as computational results from a finite element code in terms of structural eigensolutions and from a boundary element code in terms of sound pressure, directivity etc.

Visco-Elastic Fracture Analysis of IC Package under Thermal Loading (열하중하에 있는 IC 패키지의 점탄성 파괴해석)

  • 이강용;양지혁
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.1
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    • pp.43-50
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    • 1998
  • The purpose of the paper is to protect the damage of plastic IC package with searching the cause of the fracture due to the delamination and crack when the encapsulant of plastic IC package is on viscoelastic behavior with the effect of creep on high temperature, The model for analysis is the plastic SOJ package with dimpled diepad in the IR soldering process of surface mounting technology. The risk of delamination with calculating the distribution of viscoelastic thermal stress in the package without the crack in the surface mounting process is checked. The package model with the perfect delamination between chip and diepad is chosen to estimate the resistance against fracture in thermal loading with calculating C (t)-integrals according to the change of the design. The optimum design to depress the delamination and crack is presented.

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Analysis of scattering fields by conductors with arbitrary cross-section in parallel-plate waveguide (평행판 도파관내의 산란 도체에 의한 산란파 해석)

  • 정봉식;김현정;김응수;조규완
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.12
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    • pp.65-73
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    • 1995
  • In this paper, new algorithm which calculates transmission coefficient of electromagnetic wave by numerical analysis of scattered field by conductors with arbitrary cross-sections in parallel-plate waveguide is proposed. Proposed algorithm assumes magnetic current distribution on the boundary of scattering conductors, and applies Image theorem to perfect conductor surfaces of parallel-plate waveguide. Integral equations for fictitious magnetic currents on conducting boundary are set up. Magnetic current distributions on conducting boundary are expanded as exponential basis function, and using Galerkin method matrix equations are set wp. To compute matrix elements this method utilizes Fourier transform which is faster than numerical integration. Finally, frequency and incidence-angle characteristic of transmission coefficient are calculated and compared with experimental results.

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A Study on the System Furniture Design for Home Office in Korea (한국적 홈 오피스를 위한 통합 시스템가구에 관한 연구 - 30-40평형 아파트를 대상으로 -)

  • 최경란
    • Korean Institute of Interior Design Journal
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    • no.41
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    • pp.190-197
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    • 2003
  • This study is based on the Importance of home office in domestic environment in Korea. In recent years, the distribution of network environment at home has been changed rapidly Each family member uses home office for various purpose. The home office in domestic living environment become a part of common use for all family member. The purpose of this study is to set the framework of design direction in terms of system furniture for home office within the limitation of current standard space at home such as typical apartment - 30 pyeong, 40 pyeong. The first step of study is to understand user space and user needs through the user survey. The second step is to find the right location and plan of home office in domestic environment. The last is to suggest the integral system furniture and elements that fits to the various situations of location according to the space and user type.

A novel four variable refined plate theory for laminated composite plates

  • Merdaci, Slimane;Tounsi, Abdelouahed;Bakora, Ahmed
    • Steel and Composite Structures
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    • v.22 no.4
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    • pp.713-732
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    • 2016
  • A novel four variable refined plate theory is proposed in this work for laminated composite plates. The theory considers a parabolic distribution of the transverse shear strains, and respects the zero traction boundary conditions on the surfaces of the plate without employing shear correction coefficient. The displacement field is based on a novel kinematic in which the undetermined integral terms are used, and only four unknowns are involved. The analytical solutions of antisymmetric cross-ply and angle-ply laminates are determined via Navier technique. The obtained results from the present model are compared with three-dimensional elasticity solutions and results of the first-order and the other higher-order theories reported in the literature. It can be concluded that the developed theory is accurate and simple in investigating the bending and buckling responses of laminated composite plates.

ON THE PRIMES WITH $P_{n+1}-P_n = 8$ AND THE SUM OF THEIR RECIPROCALS

  • Lee Heon-Soo;Park Yeon-Yong
    • Journal of applied mathematics & informatics
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    • v.22 no.1_2
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    • pp.441-452
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    • 2006
  • We introduce the counting function ${\pi}^*_{2.8}(x)$ of the primes with difference 8 between consecutive primes ($p_n,\;p_{n+l}=p_n+8$) can be approximated by logarithm integral $Li^*_{2.8}$. We calculate the values of ${\pi}^*_{2.8}(x)$ and the sum $C_{2,8}(x)$ of reciprocals of primes with difference 8 between consecutive primes $p_n,\;p_{n+l}=p_n+8$ where x is counted up to $7{\times}10^{10}$. From the results of these calculations. we obtain ${\pi}^*_{2.8}(7{\times}10^{10}$)= 133295081 and $C_{2.8}(7{\times}10^{10}) = 0.3374{\pm}2.6{\times}10^{-4}$.

An Analysis for Delaminations in CFRP Laminates (CFRP 적층복합재료의 층간분리 평가)

  • Kang, Ki-Weon;Kim, Jung-Kyu
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.132-137
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    • 2000
  • In this study, model for arrest toughness is proposed in consideration of fracture behavior of composite materials. Also, the probabilistic model is proposed to describe the variability of arrest toughness due to the nonhomogeneity of material. For these models. experiments were conducted on the Carbon/Epoxy composite plates with various thickness using the impact hammer. The elastic work fatter used in J-Integral is applicable to the evaluation of energy release rate. The fracture behavior call be described by crack arrest concept and the arrest toughness is independent of the delamination size. Additionally, a probabilistic characteristics of arrest toughness is well described by the Weibull distribution function. An increasing of thickness raises a variation of arrest toughness.

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Comparative Analysis of the Parabolic and Hyperbolic Heat Conduction and the Damped Wave in a Finite Medium (유한한 평판에서 포물선형 및 쌍곡선형 열전도 방정식과 파동 방정식의 비교 해석)

  • Park, S.K.;Lee, Y.H.
    • Journal of Power System Engineering
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    • v.3 no.3
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    • pp.14-21
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    • 1999
  • The wave nature of heat conduction has been developed in situations involving extreme thermal gradients, very short times, or temperatures near absolute zero. Under the excitation of a periodic surface heating in a finite medium, the hyperbolic and parabolic heat conduction equations and the damped wave equations in heat flux are presented for comparative analysis by using the Green's function with the integral transform technique. The Kummer transformation is also utilized to accelerate the rate of convergence of these solutions. On the other hand, the temperature distributions are obtained through integration of the energy conservation law with respect to time. For hyperbolic heat conduction, the heat flux distribution does not exist throughout all the region in a finite medium within the range of very short times(${\xi}<{\eta}_l$). It is shown that due to the thermal relaxation time, the hyperbolic heat conduction equation has thermal wave characteristics as the damped wave equation has wave nature.

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Fatigue Crack Growth Simulation of Arbitrarily Shaped Three Dimensional Cracks Using Finite Element Alternating Method (유한요소 교호법을 이용한 임의 형상의 삼차원 균열의 피로균열 성장 해석)

  • Park, Jai-Hak;Kim, Tae-Soon
    • Journal of the Korean Society of Safety
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    • v.21 no.1 s.73
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    • pp.15-20
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    • 2006
  • The finite element alternating method is a convenient and efficient method to analyze three-dimensional cracks embedded in an infinite or a finite body because the method has the property that the uncracked body and cracks can be modeled independently. In this paper the method was applied for fatigue crack growth simulation. A surface crack in a cylinder was considered as an initial crack and the crack configurations and stress intensity factors during the crack growth were obtained. In this paper the finite element alternating method proposed by Nikishkov, Park and Atluri was used after modification. In the method, as the required solution for a crack in an infinite body, the symmetric Galerkin boundary element method formulated by Li and Mear was used. And a crack was modeled as distribution of displacement discontinuities, and the governing equation was formulated as singularity-reduced integral equations.

A Nodal Probabilistic Production Cost Evaluation at each Load Point using Monte Carlo Simulation Methods (Monte Carlo Simulation을 이용한 각 부하지점별 확률론적 발전비산정)

  • Moon, Seung-Pil;Kim, Hong-Sik;Choi, Hyong-Lim;Choi, Jae-Seok;Rho, Dae-Seok
    • Proceedings of the KIEE Conference
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    • 2001.07a
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    • pp.530-532
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    • 2001
  • This paper illustrates a method for evaluating nodal probabilistic production cost using the CMELDC. A new method for constructing CMELDC(the equivalent load duration curves of composite power system) was developed by authors. The CMELDC can be obtained by convolution integral processing between the probability distribution functions of the fictitious generators outage capacity and the load duration curves at each load point. Monte Carlo Methods are applied for the construction of CMELDC on this study. And IEEE-RTS 24 buses model is used as our case study with satisfactory results.

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