• Communications for Statistical Applications and Methods
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• 제19권3호
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• pp.479-493
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• 2012

The inverse Weibull distribution(IWD) is a complementary Weibull distribution and plays an important role in many application areas. In this paper, we develop a Bayesian estimator in the context of record statistics values from the exponentiated inverse Weibull distribution(EIWD). We obtained Bayesian estimators through the squared error loss function (quadratic loss) and LINEX loss function. This is done with respect to the conjugate priors for shape and scale parameters. The results may be of interest especially when only record values are stored.

• Advances in aircraft and spacecraft science
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• 제6권5호
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• pp.409-426
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• 2019

The aim of the present work is to study the nonlinear behavior of the laminated composite plates under transverse sinusoidal loading using a new inverse trigonometric shear deformation theory, where geometric nonlinearity in the Von-Karman sense is taken into account. In the present theory, in-plane displacements use an inverse trigonometric shape function to account the effect of transverse shear deformation. The theory satisfies the traction free boundary conditions and violates the need of shear correction factor. The governing equations of equilibrium and boundary conditions associated with present theory are obtained by using the principle of minimum potential energy. These governing equations are solved by eight nodded serendipity element having five degree of freedom per node. A square laminated composite plate is considered for the geometrically linear and nonlinear formulation. The numerical results are obtained for central deflections, in-plane stresses and transverse shear stresses. Finite element Codes are developed using MATLAB. The present results are compared with previously published results. It is concluded that the geometrically linear and nonlinear response of laminated composite plates predicted by using the present inverse trigonometric shape function is in excellent agreement with previously published results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.293-296
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• 2002

This work presents the reconstruction of impact force produced by the collision between two elastic structures. The 2-DOF impactor was designed. The shape control of impact farce using correlations of the dynamic characteristics and impact force history between two elastic structures is accomplished. The effects of the relative motion between impactor and elastic structure on the impact force shape are studied. Reconstruction characteristics of impact force in cantilever beam are reviewed.

• 대한전자공학회논문지
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• 제25권3호
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• pp.243-251
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• 1988

A new technique to reconstruct complex permittivity profiles of dielectric objects by using the moment-method solutions to the electric field integral equation iversely is presented here. Performing numerical calcualtions for several type of dielectric objects by employing the present scheme, it is demonstrated that this inverse technique provides the superresolution of the reconstructed permittivity profiles regardless of the location measured the scattered field, the size and shape of dielelctric objects and the permittivity profile.

• International Journal of Aeronautical and Space Sciences
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• 제10권1호
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• pp.14-19
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• 2009

The typical aeroelastic analysis for a complex configuration such as a complete aircraft was done using the aerodynamic results of the wing and the structural modes of a complete aircraft; that is, the aerodynamics of a wing of a complete aircraft is assumed to be not much influenced by the body shape. Nevertheless, the body shape can cause a distortion of aerodynamic pressure on the wing surface and it is necessary to investigate the body effect in flutter analysis. In this reseasrch, MGM inverse design method is applied to include the body effect of a wing-body model which disturbs the pressure distribution on the wing surface.

• International Journal of Automotive Technology
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• 제7권3호
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• pp.283-288
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• 2006

A mathematical methodology is proposed for designing nozzle hole shapes producing controlled geometric cavitation. The proposed methodology uses an unstructured RANS flow solver, with the ability to compute sensitivity derivatives via an adjoint algorithm. The adjoint formulation for the N-S equations is presented while variation of the turbulence viscosity is not taken into account during the geometry modifications. The sensitivities are calculated in a mode independently of the shape parameterisation. The method is used to develop and evaluate conceptual shapes for nozzle hole cavitation reduction. The localized region at the hole inlet producing cavitation, is parameterised using its radius of curvature, while a cost function is formulated to eliminate the negative pressures present at this location. Sensitivity derivatives are used to assess the dependence of the localized region on the minimum pressure, and to drive the geometry to the targeted shape. The results show that the computer model can provide nozzle hole entry shapes that produce predefined flow characteristics, and thus can be used as an inverse design tool for nozzle hole cavitation control.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 춘계학술대회 논문집
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• pp.125-128
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• 2002

The automotive industry have made an effort to reduce the weight of vehicle structures with increased safety, while initial model of the final product does not contain any prehistoric effects in a design stave. It takes lots of time to calculate forming effects that have great influences on the energy absorption of structures. In this paper, finite element inverse analysis is adopted to calculate forming effects, such as thickness variation and effective plastic strain as well as an initial blank shape with small amount of computation time. Crash analysis can be directly performed after inverse analysis of the forming process without remeshing scheme. The direct mesh mapping method is used to calculate an initial guess from the sliding constraint surface that is extracted from the die and punch set. Analysis results show that energy absorption of structures is increased with consideration of forming effects and finite element inverse analysis is usefully applicable to calculate forming erects of vehicle structures for the crash analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.585-588
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• 2005

Many process parameters have an effect on the auto-body panel forming process. A well designed blank shape causes the material to flow smoothly, reduces the punch and yields a product with uniform thickness distribution. Therefore, the determination of an initial blank shape plays the important role of saving time and cost in the auto-body panel forming process. For these reasons, some approaches to estimate the initial blank shape have been implemented, in this paper The one-step approach using a finite element inverse method will be introduced to predict the optimal forming with changing of blank pressure the developed program is applied to auto-body panel forming.

• 응용통계연구
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• 제29권3호
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• pp.425-435
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• 2016

본 논문에서는 1973년부터 2014년까지 42년 간, 12개 지역의 일일 강수량 데이터의 역통계(inverse statistics) 분석을 실시하였다. 구체적으로 일일 강수량 x의 확률밀도함수 f(x)를 도출하였고, 특정 강수량 ${\rho}$를 처음으로 넘어서는 기간 ${\tau}_{\rho}$의 분포 $f({\tau}_{\rho})$를 도출하였다. 최종적으로 ${\tau}_{\rho}$의 대푯값인 ${\tau}_{mean}({\rho})$와 ${\rho}$의 관계를 도출하였다. 분석 결과 x와 ${\tau}_{\rho}$는 확장된 지수분포(stretched exponential distribution)를 이루는 것을 확인하였다. 더불어 ${\rho}$와 ${\tau}_{mean}({\rho})$도 확장된 지수함수의 관계를 이루는 것을 알 수 있었다. 이들 분포를 바탕으로 형태 모수(shape parameter) ${\beta}$ 값을 도출하고, 12개 지역의 강수 특성을 분석하였다.

• 비파괴검사학회지
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• 제23권6호
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• pp.622-634
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• 2003

This paper is concerned with a computational method for recovering a crack shape of steam generator tubes of nuclear plants. Problems on the shape identification are discussed arising in the characterization of a structural defect in a conductor using data of eddy current inspection. A surface defect on the generator tube ran be detected as a probe impedance trajectory by scanning a pancake type coil. First, a mathematical model of the inspection process is derived from the Maxwell's equation. Second, the input and output relation is given by the approximate model by virtue of the hybrid use of the finite element and boundary element method. In that model, the crack shape is characterized by the unknown coefficients of the B-spline function which approximates the crack shape geometry. Finally, a parameter estimation technique is proposed for recovering the crack shape using data from the probe coil. The computational experiments were successfully tested with the laboratory data.