• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.170-179
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• 2007

This paper introduces the optimal disposition of direction finder using EM(Electro-magnetic) wave propagation analysis which is based on LR(Longley-Rice) propagation model and the characteristics of direction finder, emitter and terrain. Initial model is simulated and modified to minimize propagation error as a result of the field trials. Proposed analysis used line-of-sight analysis and mountain-top extraction algorithm to optimize the disposition in the assigned area and the result can be displayed in the 3D map in order of the percentage coverage for direction finding possibility area.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.94-96
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• 2009

This paper deals with the design considerations of electro-magnet (EM)-permanent magnet (PM) hybrid levitation and propulsion device for magnetically levitated (maglev) vehicles. Several design considerations such as machine structure, manufacturing, and control strategy are described. In order to verify the design scheme and feasibility of control strategy, dynamic test set is implemented and tested.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1716-1721
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• 2014

In this paper, a study on automation method for the circuit/EM (Electro-Magnetic) simulation is carried out to analyze effectively the SI/PI (Signal Integrity/Power Integrity) issues which occur on circuits and/or PCBs (Printed Circuit Boards). For the automation of the circuit/EM simulation, algorithms performing each process of the SI/PI analysis automatically (such as ports setup, circuit definition and SI/PI evaluation) are developed; thereby automation system for the SI/PI analysis is constructed with the algorithms. The automation of the circuit/EM simulation is accomplished in the environment of the C/S (Client/Server) architecture in order to reduce resources such as high cost computers demanded for the SI/PI analysis. The automation method for the SI/PI analyses proposed in this paper reduces effort, time, and cost spent on the environment setup for simulation and the SI/PI analysis process. In addition, the proposed method includes automation of the documenting process, which organizes, records and displays the SI/PI analysis results automatically for users.

• The Journal of Korea Robotics Society
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• v.11 no.3
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• pp.156-162
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• 2016

For the underwater localization, acoustic sensor systems are widely used due to greater penetration properties of acoustic signals in underwater environments. On the other hand, the good penetration property causes multipath and interference effects in structured environment too. To overcome this demerit, a localization method using the attenuation of electro-magnetic(EM) waves was proposed in several literatures, in which distance estimation and 2D-localization experiments show remarkable results. However, in 3D-localization application, the estimation difficulties increase due to the nonuniform (doughnut like) radiation pattern of an omni-directional antenna related to the depth direction. For solving this problem, we added a depth sensor for improving underwater 3D-localization with the EM wave method. A micro scale pressure sensor is located in the mobile node antenna, and the depth data from the pressure sensor is calibrated by the curve fitting algorithm. We adapted the depth(z) data to 3D EM wave pattern model for the error reduction of the localization. Finally, some experiments were executed for 3D localization with the fast calculation and less errors.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.605-607
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• 2000

Although Equvalent Magnetic Circuit (EMC) method. Using lumped parameter and numerical analysis method are widely used for electric machine analysis. these are neither always accurate enough nor sometimes available to easily use. Moreover three dimensional finite element method (3D-FEM) is inherently unsuitable for electric machine performance evaluation due to its poor computational efficiency, such as too long calculation time and difficulty in modeling for analysis. In this paper, Nonlinear Equivalent Magnetic Circuit (NEMC) method in combination with 2D-FEM is proposed to analyze the electric machine requiring 3D-FEM, and this method applys to torque evaluation for rotary actuator of Electro Magnetic Electronic Controller Power Steering (EM-ECPS).

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.29-34
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• 2004

Generally, a silicone rubber and a chloride polyethylene(CPE) have been used for the development of high-performance composite EM(ElectroMagnetic) wave absorbers. In this study, the EM wave absorption abilities for natural lacquer which is newly suggested in this study as a binder for composite EM wave absorbers were investigated to develop an improved EM wave absorbers. In addition, MnZn ferrite composite EM wave absorbers mixed with the natural lacquer were prepared and their absorption ability was also investigated. MnZn ferrite composite EM wave absorbers which employs the natural lacquer as a binder showed an improved EM wave absorption characteristics in comparison with the conventional binder such as a silicone rubber and a chloride polyethylene(CPE). The matching frequency and the absorption ability of EM wave absorbers mixed with natural lacquer can be controled the change of the thickness of them.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.623_624
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• 2009

This paper deals with the characteristic analysis of electro-magnet (EM)-permanent magnet (PM) hybrid levitation and propulsion device for magnetically levitated (maglev) vehicles. Several machine characteristics such as levitation force with/without control current and thrust are described. In order to verify the analysis results and feasibility of high-speed operation of the maglev vehicle, real-scale static test set is implemented and tested.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2043-2048
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• 2011

According to the statistical report from National Emergency Management Agency (NEMA) in Korea, the accident rate of closed switchboards in power systems occupies over 40%. In this paper, an integrated sensor module for monitoring the condition of closed switchboards is described. The sensor module monitors electro-magnetic (EM) wave, ultra-violet (UV) ray, heat and smoke generated by electrical discharges or insulation breakdown. The effective detection ranges were decided from experiment results; 100 kHz~10 MHz for EM wave, 220 nm~395 nm for UV ray and 0~$150^{\circ}C$ for heat, respectively. The prototype sensor module includes all functions above-mentioned in one device.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.4
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• pp.333-343
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• 2009

The BPF designed by the formula based on strip line shows the center frequency shift and distortion in filter response and this becomes more significant with higher frequency. In this paper, the novel design based on EM simulation is proposed. In the design, the filter is decomposed into individual resonators and, for each resonator, the reactance slope and the inverter values are measured and tuned to desired design values for a inverter BPF prototype. The filter composed with such resonators shows the desired filter response without further tuning. This is because possible effects of discontinuities and dispersion are included in the filter parameter extraction. The method can generally apply to all filters that can be transformed into inverter BPF prototype. The procedure is verified by designing a 5th-order SIR filter and quite general to adapt into the design of a parallel coupled line filter, and hair-pin filter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.8
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• pp.114-120
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• 2008

In this paper, we extract the parasitic elements of the metal-insulate-metal(MIM) capacitor using short-open calibration (SOC). The scattering matrixes of short, open, and MIM structures in strip lines are measured by full electro-magnetic (EM) simulator and vector network analyser. The full EM simulations are performed by finite element method (FEM) that was fitted three dimensional structure analysis. The electro-magnetic effects of MIM capacitor laminated in the multi-layered structures are proposed the II equivalent circuit with lumped elements, and the relations between the measured scattering parameters of the MIM structures and lumped elements in the circuits are shown by performing 2 port network analysis. The extracted lumped elements using the proposed SOC method are independent to frequencies.