• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.7
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• pp.117-125
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• 2004

Performing the sensitivity analysis of contact conduction on the basis of the thermal model already established, the study of thermal design is accomplished for the preparation of the future changes of mechanical interface design. A relatively simple thermal model is taken into consideration for the convenience of the analysis. A variety of the spacecraft bus voltages and the contact resistances are tried. As a consequence, when the mechanical interface condition is changed at the same module, the successful thermal design could be achieved if we design the heater to have sufficiently large power with reference to the heritage of contact resistance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.892-897
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• 2017

Until now, it has been for choosing most economic result to be generally used for designing remote MicroGrid (MG) system. It is able to make economic benefit by reducing operation cost, but proportion of renewable energy will be minimum. In other words, it is difficult to get an effect by renewable energy because economic feasibility is an only consideration. Therefore, various factors should be considered and design objectives should be are diversified to design proper remote MG system. In this paper, remote MG system is classified into two types according to design objectives, and they are analysed through case study based on economic evaluation. In addition, economic feasibility for each type is analysed through sensitivity analysis according to various factors that affect the design results of the system.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.455-460
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• 1994

This paper presents a simple methodology for reducing the order of H$_{\infty}$ controllers in the mixed sensitivity control problems. The key point of this methodology is to transform the generalized plant expression to new one, where the control object and the weighting functions for the sensitivity function may have some poles on the imaginary axis. So that, this methodology makes it possible to use the standard method to solve the general H$_{\infty}$ design problems about the mixed sensitivity problems, even for a servo system or a oscillatory system. We derive that the order of H$_{\infty}$ controllers designed by this methodology may be reduced to n$_{p}$ where n$_{p}$ is the order of the denominator of the control object. It is clear that n$_{p}$ is lower than n$_{p}$ + n$_{s}$, which is the order of H$_{\infty}$ controllers obtained by the ordinary H$_{\infty}$ design method up to now, where n$_{s}$ is the order of the denominator of the weighting function for sensitivity. Finally, a numerical example is given to illustrate the results..lts.ts..lts.lts.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.3
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• pp.8-16
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• 2006

This paper discusses design sensitivity analysis and its application to a structural dynamics modification. Eigenvalue derivatives are determined with respect to the element parameters, which include intrinsic property parameters such as Young's modulus, density of the material, diameter of a beam element, thickness of a plate element, and shape parameters. Derivatives of stiffness and mass matrices are directly calculated by derivatives of element matrices. The first and the second order derivatives of the eigenvalues are then mathematically derived from a dynamic equation of motion of FEM model. The calculation of the second order eigenvalue derivative requires the sensitivity of its corresponding eigenvector, which are developed by Nelson's direct approach. The modified eigenvalue of the structure is then evaluated by the Taylor series expansion with the first and the second derivatives of eigenvalue. Numerical examples for simple beam and plate are presented. First, eigenvalues of the structural system are numerically calculated. Second, the sensitivities of eigenvalues are then evaluated with respect to the element intrinsic parameters. The most effective parameter is determined by comparing sensitivities. Finally, we predict the modified eigenvalue by Taylor series expansion with the derivatives of eigenvalue for single parameter or multi parameters. The examples illustrate the effectiveness of the eigenvalue sensitivity analysis for the optimization of the structures.

• The Journal of the Acoustical Society of Korea
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• v.19 no.3
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• pp.92-99
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• 2000

In this paper, theoretical acoustic sensitivity was derived to describe acousto-optic transduction property of the mandrel type fiber optic acoustic sensor with respect to external acoustic field. The acoustic sensitivity was analyzed in relation to both material properties and geometrical influence factors of the constitutional parts of the sensor, analytically. Validity of the theoretical results were verified through comparison with the finite element analysis results. The variation trends of the sensitivity of the sensor in relation to the studied parameters showed good agreement for the two analysis methods. According to the results, it is considered more economical to design the basic structure of the sensor with the analytic equations developed in this paper, and then to carry out further detailed analysis with the finite element method for specific points of design interest.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.75-82
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• 2006

In this paper, we design the meander line inductors with high sensitivity and high quality factor(Q) using high characteristic impedance of aperture ground plate. Sensitivity as a frequency is new defined by variation of effective inductance per analysis frequency range instead of self resonance frequency (SRF). An equivalent lumped circuit is derived to explain the characteristic of high frequency inductor. The 4 nH meander line inductor with aperture ground plate has 0.45 nH/GHz of good sensitivity and 86 of Q at 0.7 GHz.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.11
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• pp.29-34
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• 2020

In this study, a sensitivity formulation was applied to analyze the dynamic response due to the effect of the excitation force for the undamped vibration of the cantilever beam. The theoretically fundamental formulations were derived considering an eigenvalue problem and its modal analysis to govern the second order algebraic differential equation in terms of the change in the modal coordinate with respect to the design parameters. A representative physical quantity pertaining to the dynamic response, that is, the rate of change in the dynamic displacement, was observed by changing the design variables, such as the cross-sectional area of the beam. The numerical results were obtained at various locations, considering the application of the external forces and observation of the dynamic displacement. When the detection position was closer to the free end of the cantilever beam, the sensitivity of the dynamic displacement was higher, as predicted through the oscillating motion of the beam. The presented findings can provide guidance to compute the dynamic sensitivity for a flexibly connected structure under dynamic excitations.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.2
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• pp.185-196
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• 2006

Statement of problem: The researches on the influence of design variables on the stress distribution in cortical and trabecular bones and on optimal design for implant system were limited. Purpose: The purpose of this study is to identify the sensitivities of design parameters and to suggest the optimal parameters for designing the onebody type implant system. Material and methods: Stresses arising in the implant system were obtained by finite element analysis using a three dimensional model. An onebody type implant system[Oneplant (Warrantec. Co. Ltd., Korea)] was considered in this study. Vortical load(150 N) was applied on the top of the abutment along the axial direction. The initial design variables set for sensitivity analysis were radius of fixture, numbers of micro thread, numbers of power thread, height of micro thread, future length, tapered angle of future, inclined angle of thread, width of micro thread and width of power thread. The statistical technique of Design of Experiments(DOE) was applied tn the simulation model to deduce effective design parameters on stress distributions in bones. The deduced design parameters were incorporated into a fully automated design tool which is coupled with the finite element analysis and numerical optimization to determine the optimal design parameters. Results: 1. The result of sensitivity analysis showed six design variables - radius of future, tapered angle of fixture, inclined angle of thread, numbers of power thread, numbers of micro thread and height of micro thread - were more influential than the others. 2. The optimal values of design variables can be deduced by coupling finite element analysis (FEA) and design optimization tool(DOT).

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.3
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• pp.198-204
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• 2007

The modelling and design of the PCV(Pressure Control Valve) for passenger car CVT(Continuously Variable Transmission) are considered in this paper. For analysis and design, the simulation model of the PCV is derived by using commercial software, AMESim. For a good design of the PCV, the sensitivity analysis for design parameters is carried out and the static and dynamic characteristics of the developed PCV are experimented. The simulation and experimental results are presented to show the validity of the design process.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.11
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• pp.546-555
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• 2001

ln this paper, the optimum design of electrical apparatus using design variable parametrization is presented. For analysis and design, the finite element method and the design sensitivity method is used, respectively. By applying the parametrization of the design variables, the obtained designed shape is continuous and smooth. For the parametrization the Bezier spline is used. The designed shape with parametrization is characterized by the control points. By delivering control points to the commercial CAD packages or NC machines, the exact designed shape can be realized in the manufacturing the electrical apparatus. The designed results with and without parametrization are compared and the validity of the parametrization is verified.