• Journal of the Korean Society for information Management
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• v.39 no.1
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• pp.309-330
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• 2022

Intellectual structure analysis, which quantitatively identifies the structure, characteristics, and sub-domains of fields, has rapidly increased in recent years. Analysis techniques traditionally used to conduct intellectual structure analysis research include bibliographic coupling analysis, co-citation analysis, co-occurrence analysis, and author bibliographic coupling analysis. This study proposes a novel intellectual structure analysis method, Keyword Bibliographic Coupling Analysis (KBCA). The Keyword Bibliographic Coupling Analysis (KBCA) is a variation of the author bibliographic coupling analysis, which targets keywords instead of authors. It calculates the number of references shared by two keywords to the degree of coupling between the two keywords. A set of 1,366 articles in the field of 'Open Data' searched in the Web of Science were collected using the proposed KBCA technique. A total of 63 keywords that appeared more than 7 times, extracted from 1,366 article sets, were selected as core keywords in the open data field. The intellectual structure presented by the KBCA technique with 63 key keywords identified the main areas of open government and open science and 10 sub-areas. On the other hand, the intellectual structure network of co-occurrence word analysis was found to be insufficient in the overall structure and detailed domain structure. This result can be considered because the KBCA sufficiently measures the relationship between keywords using the degree of bibliographic coupling.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.4
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• pp.87-93
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• 2002

In this study, basic concepts of magnet were introduced, and dynamic characteristics of magnet coupling were explored. Based on these characteristics, it was proposed how to analyze transverse and torsional vibrations of a spindle system with magnet coupling. Proposed theoretical approaches were applied to a precision power transmission system machined for this study, and the transverse and torsional vibrations were simulated. The force on magnet coupling was shown as a form of nonlinear function of the gap and the eccentricity. Also, the form of torque transmitted by magnet coupling was considered as a sinusoidal function. Main spindle connected to a coupling of a follower part was assumed to be a rigid body. Nonlinear partial differential equation was derived to be as a function of angular displacement. By using the equation, torsional vibration analysis of a spindle system with magnet coupling was performed. Free and forced vibration analyses of a spindle system with magnetic coupling were explored by using FEM.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.9 s.114
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• pp.912-918
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• 2006

A modeling method for the vibration analysis of rotating multi-blade systems considering the coupling stiffness effect is presented in this paper. Blades are assumed as cantilever beams and the coupling stiffness effect originates from disc or shroud between blades. As the angular speed, hub radius ratio, and the coupling stiffness vary, the natural frequencies of the system vary. Numerical results show that the coupling stiffness is very important to estimate the natural frequencies. Along with the natural frequencies, associated mode shapes, critical angular speed, and critical hub radius ratio are obtained through the analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1354-1359
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• 2006

A modeling method for the vibration analysis of rotating multi-blade systems considering the coupling stiffness effect is presented in this paper. Blades are assumed as cantilever beams and the coupling stiffness effect originates from disc or shroud between blades. As the angular speed, hub radius ratio, and the coupling stiffness vary, the natural frequencies of the system vary. Numerical results show that the coupling stiffness is very important to estimate the natural frequencies. Along with the natural frequencies, associated mode shapes, critical angular speed, and critical hub radius ratio are obtained through the analysis.

• Earthquakes and Structures
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• v.16 no.1
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• pp.83-96
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• 2019

The seismic behavior of PRC coupling beam-hybrid coupled shear wall system is analyzed by using the finite element software ABAQUS. The stress distribution of steel plate, reinforcing bar in coupling beam, reinforcing bar in slab and concrete is investigated. Meanwhile, the plastic hinges developing law of this hybrid coupled shear wall system is also studied. Further, the effect of coupling ratio, section dimensions of coupling beam, aspect ratio of single shear wall, total height of structure and the role of slab on the seismic behavior of the new structural system. A fitting formula of plate characteristic values for PRC coupling beams based on different displacement requirements is proposed through the experimental date regression analysis of PRC coupling beams at home and abroad. The seismic behavior control method for PRC coupling beam-hybrid coupled shear wall system is proposed based on the continuous connection method and through controlling the coupling ratio, the roof displacement, story drift angle of hybrid coupled shear wall system, displacement ductility of coupling beam.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.437-442
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• 2002

The purpose of this study is to investigate nonlinear behavior and estimate ultimate resistance of the wall structure against seismic loading. Experimental data for RC coupling elements are used for specifying the strength deterioration and stiffness degradation factor of hysteretic model. Modified coupling element models are used in the push over analysis and time history analysis. In the time history analysis, three earthquake waves are used in the analysis and their peak ground accelerations are changed to be 0.2g. The conclusions of this study are as follows : (1) In the push over analysis, yielding of coupling elements occurred at lower story with small story drift ratio as 0.3%. (2) In the time history analysis, the story drift ratio is sufficient for the requirement of Korean Code, But coupling elements at most stories of the buildings occurred yielding. i. e. the earthquake resistant capacity of shear wall structures is not sufficient at 0.2g.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.7
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• pp.276-282
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• 1985

This study is concerned with the analysis of two-dimensional steady magnetic fields by the coupling of FEM and BEM. FEM(Finite Element Method)is most widely used as a method of numerical analysis and BEM (Boundary Element Method)is a newest method for it. And the results from this coupling method are compared and discussed with those of FEM only. Consequently, it is shown that to obtain the same accuracy of results the coupling method requires less calculating time and dimension than the FEM.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.734-743
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• 2010

In this paper, we analyzed the EMP coupling for the nonuniform transmission lines, such as twisted cables, using the chain matrix algorithm and the multi-conductor analysis. The BLT method is widely used for the EMP coupling analysis of the transmission line, however, it is difficult to apply to the nonuniform transmission lines. In order to analyze the EMP coupling of nonuniform transmission lines, the whole nonuniform transmission line is divided into incremental uniform line sections of the finite numbers, and the coupling in each small sections is now summed up to get the EMP coupling effect of the entire nonuniform transmission line. To verify the proposed EMP coupling analysis method, the result of the EMP coupling simulation is compared with the solution of BLT equations for a uniform transmission line case. The proposed method is applied to the twisted cable over ground in case of being illuminated by the HEMP in order to analyze the EMP coupling.

• The KSFM Journal of Fluid Machinery
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• v.16 no.3
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• pp.32-38
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• 2013

This paper deals with the study on the rotordynamic and experimental analysis of turbine-generator system connected with a magnetic coupling. Although magnetic coupling has been used to torque transmission of chemical processing pump rotating at under 3,600rpm, magnetic coupling in this study is applied to high-speed turbine-generator system using a working fluid that is refrigerant such as ammonia or R-124a. Results of rotordynamic design analysis are as follows. The first, shaft diameter nearest to outer hub of magnetic coupling has a big effect on the $1^{st}$ critical speed of generator rotor. The second, if the $1^{st}$ critical speeds of turbine rotor and generator rotor have enough to separation margin in comparison to rated speed, the $1^{st}$ critical speed of turbine-magnetic coupling-generator rotor train has enough to separation margin regardless of connection stiffness of magnetic coupling. The analytical FE model is guaranteed by impact test on the prototype and condition monitoring such as measurements of vibration and bearing temperature is also performed.

• Steel and Composite Structures
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• v.7 no.4
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• pp.279-301
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• 2007

When coupling beams are proportioned appropriately in coupled core wall (CCW) systems, the input energy from ground motions is dissipated primarily through inelastic deformations in plastic hinge regions at the ends of the coupling beams. It is desirable that the plastic hinges form at the beam ends while the base wall piers remain elastic. The strength and stiffness of the coupling beams are, therefore, crucial if the desired global behavior of the CCW system is to be achieved. This paper presents the results of nonlinear response history analysis of two 20-story CCW buildings. Both buildings have the same geometric dimensions, and the components of the buildings are designed based on the equivalent lateral force procedure. However, one building is fitted with steel coupling beams while the other is fitted with diagonally reinforced concrete coupling beams. The force-deflection relationships of both beams are based on experimental data, while the moment-curvature and axial load-moment relationships of the wall piers are analytically generated from cross-sectional fiber analyses. Using the aforementioned beam and wall properties, nonlinear response history analyses are performed. Superiority of the steel coupling beams is demonstrated through detailed evaluations of local and global responses computed for a number of recorded and artificially generated ground motions.