• Journal of Navigation and Port Research
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• 제36권3호
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• pp.215-223
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• 2012

To examine the interaction of the floating pontoon with a steel moment resisting frame, the static structural analysis is carried out, in which the pressure load are calculated from the forgoing fluid dynamic analysis, varying the period of wave from 3 to 15 second and for 3 cases of depth of pontoon, 1.5, 2.0, 2.5m. As results, it has shown that RAO-pitch has the linear relationship with the increase of moment of the frame and the curvature of pontoon is reversely proportional to the stiffness of pontoon. By synthesizing these results, an estimation method is proposed, which predicts the moment of frame of the different depth of pontoon based on the analysis result of an arbitrary depth of a floating pontoon. The estimation result shows considerably good agreement, compared with the analysis result.

• Nuclear Engineering and Technology
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• 제21권2호
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• pp.99-110
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• 1989

The optimal control of xenon concentration in a nuclear reactor is posed as a linear quadratic regulator problem with state feedback control. Since it is not possible to measure the state variables such as xenon and iodine concentrations directly, implementation of the optimal state feedback control law requires estimation of the unmeasurable state variables. The estimation method used is based on the Luenberger observer. The set of the reactor kinetics equations is a stiff system. This singularly perturbed system arises from the interaction of slow dynamic modes (iodine and xenon concentrations) and fast dynamic modes (neutron flux, fuel and coolant temperatures). The singular perturbation technique is used to overcome this stiffness problem. The observer-based controller of the original system is effected by separate design of the observer and controller of the reduced subsystem and the fast subsystem. In particular, since in the reactor kinetics control problem analyzed in the study the fast mode dies out quickly, we need only design the observer for the reduced slow subsystem. The results of the test problems demonstrated that the state feedback control of the xenon oscillation can be accomplished efficiently and without sacrificing accuracy by using the observer combined with the singular perturbation method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1812-1815
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• 1997

This paper treats the estimation of human impedance and their application to collaboration work robot. Initially, we performa an experiment at whcich teh human becomes a slave and the robot behaves like a master having F/T sensor on its end. the human impedance expressed interms of mass, damping, and stiffness properties are estimated based on the force data measured by F/T sensor and the positiion data of the robot. To show the effectiveness of the estimated human impedance, we perform the second experiment at which the roles of the human and the robot are reversed. It is shown that the robot using the estimated human impedance follows the trajectory commanded by human very smoothly.

• Transactions of the Korean Society of Machine Tool Engineers
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• 제16권5호
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• pp.115-121
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• 2007

Phase contrast imaging in atomic force microscopy showed a promise as an effective tool for better understanding of micromechanical properties of surfaces at nano scale. A qualitative estimation model for phase contrast images obtained with a tapping mode AFM was developed. This investigation demonstrated the high efficiency of combined analysis of topography and phase contrast images for characterizing nanosurfaces. Phase contrast images allowed estimation of relative stiffness(elastic modulus) of the sample surface. The phase contrast images revealed a significant inhomogeneity of the nano scale worn surfaces. Phase contrast images are also capable of revealing the formation of tribofilms.

• The Transactions of the Korean Institute of Power Electronics
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• 제5권6호
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• pp.575-583
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• 2000

In this paper, a novel estimation alogrithm of mechanical parameters in two-mass system proposed. The inertia of a load and a motor and the stiffness are estimated by using RLS(Recursive Least Square) algorithm and acceleration information of motor. The effectiveness of the proposed scheme is verified with simulation and experiments results.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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• pp.170-177
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• 1999

The natural period calculation equations specified in the current building code are empirical formulas that depend on height and material type of the structure. Building with the upper wall and lower frame type is a unique structure which composed of two different structural system This type of structure needs either the deep transfer girder or the thick transfer plate that brings the sudden change of stiffness and mass. Therefore the natural period equations recommended by the current code can not be applied directly. In this study the natural period of building with typical plan obtained by dynamci analysis is compared with that of various codes. Ad approximate estimation equation for the natural period of building with the upper wall and lower frame type obtained by regression analysis is recommended. by the current code can not be applied directly. In this study the natural period of building with typical plan obtained by dynamic analysis is compared with that of various codes, And approximate estimation equation for the natural period of building with the upper wall and lower frame type obtained by regression analysis is recommended.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제22권1호
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• pp.23-32
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• 1998

A shape estimation is needed to control actively a smart structure. A method is, hence, proposed to predict the deformed shape of the structure subjected to unknown external load using the signal from sensors attached to the structure. The shape estimation is based on the relationship between the deformation of the structure and the signal from the sensors. The matrix containing the relationship between the deformation and signal is obtained using fictitious force or eigenvector of global stiffness matrix. Then the deformed shape can be predicted using the linear matrix and signal from sensors attached to the structure. To verify this method, experiment and FEM were performed and it was shown that the shape estimation method based on the fictitious force predicts deflections well and more accurately than that based on eigenvector.

• Journal of Korean Society of Steel Construction
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• 제21권4호
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• pp.393-401
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• 2009

The flexural-stiffness formula of the wale for the innovative prestressed support (IPS) system was precisely derived, and the equivalent beam stiffness was introduced for application in the actual design of the IPS wale. The cable tension forces of the IPS wale were calculated in both cases, and the axial-deformation effects were included and ignored, respectively. The central displacements of the 1-post, 2-post, 3-post, and 4-post IPS wales were calculated based on the principle of virtual work. The effects of the IPS wale length and cable inclination angle were also investigated using the derived central displacements. The simplified equivalent flexural stiffness of the IPS wale is presented herein for design purposes, and the validity of the proposed design formula was verified through its comparison with the FE and analysis solutions.

• The Journal of the Convergence on Culture Technology
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• 제9권6호
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• pp.1057-1063
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• 2023

The urban railway sleeper floating track, the subject of this study, is an anti-vibration track to reduce vibration transmitted to the structure. currently, the replacement cycle of resilience pad for sleeper floating tracks is set and operated based on load. however, most previous studies were conducted on load-based structural safety aspects, such as fatigue life evaluation of sleeper anti-vibration pads and increase in track impact coefficient and track support stiffness due to increase in spring stiffness. therefore, in this study, we measure the vibration acceleration of the ballast for each analysis section and use the results of 7 million fatigue tests to calculate the spring stiffness of the resilience pad for each section. the spring stiffness of the resilience pad calculated for each section was set as the analysis data and the concrete vibration acceleration was derived analytically. the adequacy of analysis modeling was verified as the analyzed concrete bed vibration acceleration for each section was within the field-measured concrete bed vibration acceleration range. using the vibration acceleration curve according to the derived spring stiffness change, the spring stiffness of the resilience pad is estimated from the measured vibration acceleration. therefore, we would like to present a technique that can estimate the spring stiffness of resilience pad of a running track using the vibration acceleration of the measured concrete bed.

• Interaction and multiscale mechanics
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• 제5권3호
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• pp.267-284
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• 2012

In most of the design offices, analysis of the frame is carried out without considering the effect of the rigidity of mat. The analysis of the superstructure without modelling the foundation properly and conversely analysing the foundation system without considering the stiffness of the superstructure may mislead the estimation of the forces. This paper examines the parameters, which affect the interaction and they are grouped into relative stiffness factors ${\kappa}_{rs}$ and ${\kappa}_{sb}$. An interaction analysis is performed for the five storeyed space frame of 3 bays ${\times}$ 5 bays, using ANSYS finite element code. The soil was treated as an isotropic, homogenous and elastic half space medium and the following conclusions were drawn from the analyses. The differential settlement is reduced due to interaction and the performance of the mat depends on ${\kappa}_{sb}$ values. The moments $M_x$ and $M_y$ in the corner column at all the storey levels are higher in the case of the interaction analysis than in the conventional analysis. The axial forces in the peripheral columns increased and to that extent, the inner column axial loads are reduced. In the beam, more variation is seen in the support moments than in the span moments.