• Coupled systems mechanics
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• v.11 no.2
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• pp.133-149
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• 2022

The accurate prediction of elastoplasticity under prescribed workloads is essential in the optimization of engineering structures. Mechanical experiments are carried out with the goal of obtaining reliable sets of material parameters for a chosen constitutive law via inverse identification. In this work, two sample geometries made of high strength steel plates were evaluated to determine the optimal configuration for the identification of Ludwik's nonlinear isotropic hardening law. Finite element model updating(FEMU) was used to calibrate the material parameters. FEMU computes the parameter changes based on the Hessian matrix, and the sensitivity fields that report changes of computed fields with respect to material parameter changes. A sensitivity analysis was performed to determine the influence of the sample geometry on parameter identifiability. It was concluded that the sample with thinned gauge region with a large curvature radius provided more reliable material parameters.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1687-1707
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• 2023

This paper presents a molten salt reactor (MSR) design parameter sensitivity study using a nodal dynamic modelling methodology with explicitly modified point kinetics equation and Mann's model for heat transfer. Six parameters that can impact MSR safety are evaluated. A MATLAB-Simulink model inspired by Thorcon's 550MWth MSR is used for parameter evaluations. A safety envelope was formed to encapsulate power, maximum and minimum temperature, and temperature-induced reactivity feedback. The parameters are perturbed by ±30%. The parameters were then ranked by their subsequent impact on the considered safety envelope, which ranks acceptable parameter uncertainty. The model is openly available on GitHub.

• Journal of applied mathematics & informatics
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• v.3 no.2
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• pp.149-156
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• 1996

We discuss sensitivity of equilibrium points in bimatrix games depending on small variances (perturbations) of data. Applying implicit function theorem to a linear complementarity problem which is equivalent to the bimatrix game we investigate sensitivity of equi-librium points with respect to the perturbation of parameters in the game. Namely we provide the calculation of equilibrium points deriva-tives with respect to the parameters.

• Journal of Digital Convergence
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• v.17 no.7
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• pp.125-130
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• 2019

Sensitivity analysis is used to determine the effect of a change in a design parameter on the total system, and the calculated sensitivity is an important indicator of the improvement of a structure. In this study, we investigated the method of deriving and analyzing the sensitivity of design parameters by using finite element analysis and the method of improving a structure by using sensitivity analysis results. Design parameters for weight reduction design were selected using actual semiconductor inspection equipment that requires structural improvement, and the sensitivity to design parameters was calculated by using and finite difference method. We propose an improvement method that can reduce the weight while maintaining the transient response required by the equipment. By using the results of the sensitivity analysis through finite element analysis and finite difference method, we can create a structurally improved design that satisfies the desired stress or displacement by improving the design of the structure. Therefore, sensitivity analysis is applicable to various fields as well as semiconductor inspection equipment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1434-1439
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• 2012

Vehicle is a dynamic system combined with various parameters. Dynamic characteristics of a vehicle can vary with the change of these parameters. To investigate the effect of the design parameter on vehicle handling performance the sensitivity analysis is carried out by the numerical method. The vehicle model is described by equivalent cornering stiffness that considers parameters of suspension and steering system. As the analysis results show the effect on the static and dynamic characteristics of the vehicle system, the sensitivity analysis can be used for synthesis of the design parameters to improve the vehicle handling characteristics at the design stage as well as during the vehicle test under development.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.7
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• pp.354-361
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• 2015

The building energy audit is an important process when collecting basic information for improving the energy performance of existing buildings. Audit parameters should be associated with the energy performance of the building. Such audit parameters will vary according to an individual building's characteristics and energy consumption patterns, but most building energy audits are performed in the same way. The sensitivity analysis (SA) is a statistical method to quantify the correlation between inputs and outputs that can determine which input is influential to which output. Therefore, an SA can identify influential parameters when applied to building energy analysis. In this paper, we adopted the Morris method to identify building energy audit parameters and performed a Monte Carlo simulation for uncertainty analysis. As a result, this method was able to identify an influential parameter for building energy audits and reduce uncertainty in energy consumption in buildings.

• Smart Structures and Systems
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• v.18 no.2
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• pp.293-315
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• 2016

Seismic isolation is often used in protecting mission-critical structures including hospitals, data centers, telecommunication buildings, etc. Such structures typically house vibration-sensitive equipment which has to provide continued service but may fail in case sustained accelerations during earthquakes exceed threshold limit values. Thus, peak floor acceleration is one of the two main parameters that control the design of such structures while the other one is peak base displacement since the overall safety of the structure depends on the safety of the isolation system. And in case peak base displacement exceeds the design base displacement during an earthquake, rupture and/or buckling of isolators as well as bumping against stops around the seismic gap may occur. Therefore, obtaining accurate peak floor accelerations and peak base displacement is vital. However, although nominal design values for isolation system and superstructure parameters are calculated in order to meet target peak design base displacement and peak floor accelerations, their actual values may potentially deviate from these nominal design values. In this study, the sensitivity of the seismic performance of structures equipped with linear and nonlinear seismic isolation systems to the aforementioned potential deviations is assessed in the context of a benchmark shear building under different earthquake records with near-fault and far-fault characteristics. The results put forth the degree of sensitivity of peak top floor acceleration and peak base displacement to superstructure parameters including mass, stiffness, and damping and isolation system parameters including stiffness, damping, yield strength, yield displacement, and post-yield to pre-yield stiffness ratio.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.3
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• pp.359-370
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• 2023

The thermal integrity of spent nuclear fuels has to be maintained during their long-term dry storage. The detailed temperature distributions of spent fuel assemblies are essential for evaluating the integrity of their dry storage systems. In this study, a subchannel analysis model was developed for a canister of a single fuel assembly using the COBRA-SFS code. The thermal parameters affecting the peak cladding temperature (PCT) of the spent fuel assembly were identified, and sensitivity analyses were performed based on these parameters. The subchannel analysis results indicated the presence of a recirculation flow, based on natural convection, between the fuel assembly and downcomer region. The sensitivity analysis of the thermal parameters indicated that the PCT was affected by the emissivity of the fuel cladding and basket, convective heat transfer coefficient, and thermal conductivity of the fluid. However, the effects of the wall friction factor of the canister, form loss coefficient of the grid spacers, and thermal conductivities of the solid materials, on the PCT were predominantly ignored.

• Journal of Theoretical and Applied Mechanics
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• v.3 no.1
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• pp.66-80
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• 2002

The bilinear formulation proposed earlier by Peters and Izadpanah to develop finite elements in time to solve undamped linear systems, Is extended (and found to be readily amenable) to develop time finite elements to obtain transient responses of both linear and nonlinear, and damped and undamped systems. The formulation Is used in the h-, p- and hp-versions. The resulting linear and nonlinear algebraic equations are differentiated to obtain the first- and second-order sensitivities of the transient response with respect to various system parameters. The present developments were tested on a series of linear and nonlinear examples and were found to yield, when compared with results obtained using other methods, excellent results for both the transient response and Its sensitivity to system parameters. Mostly. the results were obtained using the Legendre polynomials as basis functions, though. in some cases other orthogonal polynomials namely. the Hermite. the Chebyshev, and integrated Legendre polynomials were also employed (but to no great advantage). A key advantage of the time finite element method, and the one often overlooked in its past applications, is the ease In which the sensitivity of the transient response with respect to various system parameters can be obtained. The results of sensitivity analysis can be used for approximate schemes for efficient solution of design optimization problems. Also. the results can be applied to gradient-based parameter identification schemes.

• Journal of Nutrition and Health
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• v.35 no.7
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• pp.754-762
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• 2002

This study was performed to investigate the effect of sodium intake on blood pressure and blood parameters. 20 young adult women were fed the diets containing 290.5 mEq (high-Na diet) and 51.3 mEq (low-Na diet) Na for 6 days, respectively. BMI, DBP, and MBP were significantly lower in low-Na diet than those in high-Na diet. 20 subjects were divided into 3 groups according to the salt-sensitivity. In salt-sensitive group, decreases in SBP, DBP, and MBP by low-Na diet were shown. And there were not significant difference in blood pressure of salt-resistant group between high- and low-Na diet. In count-reactive group, MBP in low-Na diet was significantly higher than that in high-Na diet. Hemoglobin, creatinine, uric acid, and haptoglobin levels in serum were significantly higher in low-Na diet than those in high-Na diet. Among groups with different salt-sensitivity, increments of haptoglobin by low-Na diet were shown in salt-sensitive and counter-reactive groups. Actually, low sodium diet affects not only the blood pressure, but other biochemical parameters which in turn affect an individual overall health. Also salt-sensitivity should be considered as an important determinant. Therefore, for the patients who need restricted Na diet, it would be suggested that various biochemical changes and individual salt-sensitivity should be carefully considered along with dietary Na manipulation.