• Journal of IKEEE
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• v.25 no.1
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• pp.95-100
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• 2021

If we know the location of the hull block and the welding feeder in the shipyard, we can easily obtain the location information of the worker. That data is very useful for implementing a workplace safety monitoring system. However, it is difficult to apply a fixed communication network to the workplace due to the specificity of the hull structure and welding process. In this study, inductive power line communication, which can replace dedicated communication line, was reviewed. A ferrite core was used as an inductive coupler to be installed on the power cable of the welding machine, and a nano-crystalline core was applied as a coupler to be fastened to the support rod of the metal block. In order to visualize the operating principle of the proposed couplers, 3D modeling and finite element analysis were performed with the COMSOL AC/DC module. In the communication performance test using an aluminum profile, when the communication channel was formed by the contact of the welding electrode, the bandwidth was kept above 6 Mbps.

• Structural Engineering and Mechanics
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• v.52 no.2
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• pp.369-389
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• 2014

Two-layer coupled or composite beams with discrete shear connectors of finite dimensions are commonly encountered in pre-fabricated construction. This paper presents the development of simplified closed-form solutions for such type of coupled beams for practical applications. A new coupled beam element is proposed to represent the unconnected segments in the beam. General solutions are then developed by an inductive method based on the results from the finite element analysis. A modification is subsequently considered to account for the effect of local deformations. For typical cases where the local deformation is primarily concerned about its distribution over the depth of the coupled beam, empirical modification factors are developed based on parametric calculations using finite element models. The developed analytical method for the coupled beams in question is simple, sufficiently accurate, and suitable for quick calculation in engineering practice.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1957-1959
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• 2004

In this paper, maxwell 3D finite element analysis program was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by 3D simulation software operated at 2.56[MHz] and some specific conditions.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.229-232
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• 2000

In this study, An active band grass filter for 2.14GHz have been designed with MMIC using negative resistance circuit. The negative resistance element was realized with a common-drain FET with series inductive feedback. The designed active filter showed an insertion loss of 0dB at 2.14GHz and a 3-dB bandwidth of 125MHz.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.583-586
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• 2000

A passive RF smart card incorporating a non volatile memory element is powered by inductive coupling to a proximately located RF reader. Therefore, the power consumption in the smart card should be low. In this study, we designed the low power passive RF smart card that is operated at 125kHz to apply to the subway ticket system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.417-426
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• 2010

This paper describes the 6-way power divider to be used as a feeding structure of the waveguide array antenna generating the plane wave at the near distance. The SMA connector has been connected at the center of the power divider in order to feed the radiating element. The six output ports made of waveguide are positioned on the peripheral of the divider. This paper proposes the method utilizing the inductive post in order to decrease the return loss. The height of the feeding pin, the diameter of the inductive post, and the distance between the feeding pin and inductive post have been investigated, and as a result, the power divider has been optimized. The simulated and measured results show the low return loss of about -40 dB. The calculated and measured transmission coefficients are -7.78 dB and -8.06 dB, respectively. The output power of the six waveguide port show equal-amplitude and equal-phase distribution. Since the power divider proposed in this paper can be expanded to the divider having several output ports, it could be easily applied to the various array antennas.

• Journal of the Korean Magnetics Society
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• v.22 no.3
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• pp.97-102
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• 2012

In this paper, a non-contact power transferring has been performed. Power Transferring by using an electromagnetic inductive coupling is more suitable for high power transmission than by using a magnetic resonance method. Power transferring system has been designed with Loading Distribution Method to divide the electric and magnetic loading for designing the magnetic core and electric coil. To design optimum shapes of magnetic yoke, 3D finite element analysis has been performed. Experimental results show good agreement with numerical ones. So, it could be adopted in the electric power transferring system for a short-distance wireless electric power transferring machine.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2615-2618
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• 2009

Double rectangular patch with 4-bridges is investigated for solution of IEEE 802.11b/g (2.4 GHz) and 802.11a (5.5 GHz). Rectangular patch for 5.5 GHz frequency band is printed on the PCB substrate and connected to another rectangular patch for 2.4 GHz frequency band with 4-bridges to obtain dual band operation in an antenna element. 4-bridges can modify the desired frequency band from its original frequency band by changing its width. Gain of 2.4 GHz patch is 5 dBi and 5.5 GHz patch is 3.7 dBi at ${\theta}=0^{\circ}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.127-131
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• 2002

The surge protector is crucial power apparatus to guarantee the safe operation of power transmission of underground cable which can effectively restrain the overvoltage and inductive lightning stroke in power system. The surge protector is crucial power apparatus to guarantee the safe operation of power transmission of underground cable which can effectively restrain the overvoltage and inductive lightning stroke in power system. This paper described the results of a study on the performance for surge protector for underground cable. And, the performance of surge protector was evaluated through such as measurement of the reference voltage, residual voltage and impulse current etc. In results of surge protector, reference and residual voltage of ZnO element is 4.75 kV, 9.86 kV respectively. Also, In the impulse current test, thermal properties are good, despite of that polymeric housing of surge protector has thick structure. Therefore the developed surge protector is thought to apply for underground cable.

• Journal of Power Electronics
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• v.13 no.4
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• pp.701-711
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• 2013

This paper takes into account the influence of the different impedances of distribution lines on power distribution among inverters when the inverters are paralleled with the droop control method. The impact of distribution lines on the power distribution of inverters can be divided into two aspects. Firstly, since the distributed generators are in low voltage grids, there is resistive impedance in the distribution lines, which will cause control coupling and reduce system stability. The virtual negative resistive impedance of inverters is adopted in this paper to neutralize the resistive element of distribution lines and thus make the distribution line impedance purely inductive. Secondly, after solving the resistive impedance problem, the difference in the inductive impedance value of distribution lines due to the low density of distributed generators will cause an unequal share of reactive power. With regards to this problem, modification is put forward for the droop control strategy to share the reactive power equally. The feasibility of the design is validated by simulation and experimental results.