• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.166-173
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• 1997

Influence coefficients on two-plane flexible rotor balancing model are derived by using the transfer matrix method. The model has a rigid uniform cylinder at mid-span of flexible shafts. Both faces of the rigid cylinder are used as the balancing planes. Calculated influence coefficients show that there exist the rotating speed ranges which are useless or insensitive for the balancing. Gyroscopic effect and damping are considered in the study and their effects are discussed.

• Structural Engineering and Mechanics
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• v.1 no.1
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• pp.119-135
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• 1993

The paper presents a generalized optimal active control algorithm for earthquake-resistant structures. The study included the weighting matrix configuration, stability, and time-delays for achieving control effectiveness and optimum solution. The sensitivity of various time-delays in the optimal solution is investigated for which the stability regions are determined. A simplified method for reducing the influence of time-delay on dynamic response is proposed. Numerical examples illustrate that the proposed optimal control algorithm is advantageous over others currently in vogue. Its feedback control law is independent of the time increment, and its weighting matrix can be flexibly selected and adjusted at any time during the operation of the control system. The examples also show that the weighting matrix based on pole placement approach is superior to other weighting matrix configurations for its self-adjustable control effectiveness. Using the time-delay correction method can significantly reduce the influence of time-delays on both structural response and required control force.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.7
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• pp.1730-1737
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• 1994

Theoretical equations for an influence of fiber breaks on the frictional heating phenomenon in a uniaxially fiber-reinforced ceramic matrix composite are formulated. The microslip and gross slip phases are considered for deriving the equations. During a complete loading/unloading cycle, the work done against friction is derived. In order to estimate interfacial shear in a unidirectionally reinforced ceramic matrix composite which has fiber fractures as well as matrix cracks, parametric studies using the derived equations are done. In a case of less than 10% fiber fractures, additional frictional work due to fiber breaks can be neglected compared to the rest.

• Journal of Power System Engineering
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• v.21 no.2
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• pp.70-76
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• 2017

When Timoshenko arcs considering the shear deformation and rotatory inertia have elastic supports, the authors analyze in-plane free vibration of them by the transfer influence coefficient method. This method finds the natural frequencies of them using the transfer of influence coefficient after obtaining the transfer matrix of arc element from numerical integration of the differential equations governing the vibration of arc. In this study, two computer programs were made by the transfer influence coefficient method and the transfer matrix method for analyzing free vibration of Timoshenko arcs. From numerical results of four computational models, we confirmed that the transfer influence coefficient method is a reliable method when analyzing the free vibration of Timoshenko arcs. In particular, the transfer influence coefficient method is a effective method when analyzing the free vibration of arcs with rigid supports.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1303-1304
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• 2006

The type, volume fraction, size, shape and arrangement of embedded particles influence the mechanical properties of the particle reinforced metal matrix composites. This presents the investigation of the SiC particle and porosity distributions in various aluminum matrix composites produced by cold- and hot-pressing. The microstructures were characterized by optical microscopy and stereological parameters. SiC and porosity volume fractions, and the anisotropy distribution function were measured to establish the influence of the consolidation method.

• Smart Structures and Systems
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• v.25 no.2
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• pp.169-181
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• 2020

Sensor placement is a crucial aspect of bridge health monitoring (BHM) dedicated to accurately estimate and locate structural damages. In addressing this goal, a sensor placement framework based on the deflection influence line (DIL) analysis is here proposed, for the optimal design of damage detection-oriented BHM system. In order to improve damage detection accuracy, we explore the change of global stiffness matrix, damage coefficient matrix and DIL vector caused by structural damage, and thus develop a novel sensor placement framework based on the Fisher information matrix. Our approach seeks to determine the contribution of each sensing node to damage detection, and adopts a distance correction coefficient to eliminate the information redundancy among sensors. The proposed damage detection-oriented optimal sensor placement (OSP) method is verified by two examples: (1) a numerically simulated three-span continuous beam, and (2) the Pinghu bridge which has existing real damage conditions. These two examples verify the performance of the distance corrected damage sensitivity of influence line (DSIL) method in significantly higher contribution to damage detection and lower information redundancy, and demonstrate the proposed OSP framework can be potentially employed in BHM practices.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1429-1433
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• 2009

The likelihood distance for the joint distribution of two multivariate normal distributions with common covariance matrix is explicitly derived. It is useful for identifying outliers which do not follow the joint multivariate normal distribution with common covariance matrix. The likelihood distance derived here is a good ground for the use of a generalized Wilks statistic in influence analysis of two multivariate normal data.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.124-128
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• 2009

In this study, the effect of multi-step purification or functionalization on physicochemical properties of multi-walled carbon nanotubes (MWNTs)/epoxy (EP) nanocomposites was investigated. The nanocomposites containing multi-step purified MWNTs showed a stronger influence on $T_g$ and increased in mechanical properties in comparison to nanocomposites containing the same amount of only purified MWNTs. Consequently, the multi-step purification of MWNTs led to an improvement of thermomechanical properties of nanocomposites, resulting from improving the intermolecular interaction of MWNTs in epoxy matrix resins.

• Communications for Statistical Applications and Methods
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• v.12 no.3
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• pp.635-642
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• 2005

In statistical diagnostics a large number of influence measures have been proposed for identifying outliers and influential observations. However it seems to be few accounts of the influence diagnostics on test statistics. We study influence analysis on the likelihood ratio test statistic whether the two sets of variables are uncorrelated with one another or not. The influence of observations is measured using the case-deletion approach, the influence function. We compared the proposed influence measures through two illustrative examples.

• Macromolecular Research
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• v.16 no.2
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• pp.108-112
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• 2008

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of nonpolar polymeric materials is affected by the sample preparation as well as the matrix and cationizing agent. This study examined the influence of silver salt types on the MALDI analysis of polybutadiene (PB). Silver trifluoroacetate (AgTFA), silver benzoate (AgBz), silver nitrate ($AgNO_3$), and silver p-toluenesulfonate (AgTS) were used as the silver salts to compare the MALDI mass spectra of PB. The mixture solution of PB and 2,5-dihydroxybenzoic acid (DHB), as a matrix dissolved in THF, was spotted on the sample plate and dried. A droplet of the aqueous silver salt solution was placed onto the mixture. The mass spectrum with AgBz showed the clear $[M+Ag]^+$ ion distribution of PB while the mass spectrum with AgTFA did not show $[M+Ag]^+$ ions but only silver cluster ions. The mass spectra with $AgNO_3$ and AgTS did not show a clear $[M+Ag]^+$ ion distribution. The difference in the formation of $[M+Ag]^+$ ions of PB depending on the silver salts was attributed to the silver cation transfer reaction between the silver salt and the matrix (DHB). The mass spectrum showed a clear $[M+Ag]^+$ ion distribution of PB when the conjugate acid of the silver salt was less acidic than the matrix.