• Journal of the Optical Society of Korea
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• v.19 no.4
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• pp.371-375
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• 2015

The impact of equivalent optical bandwidth on the performance of a system using a reflective electroabsorption modulator (R-EAM) based optical source has been experimentally evaluated with signals operating at 2.5 Gb/s and beyond. The equivalent optical bandwidth of our source with a broadband seed light was simply adjusted by using a bandwidth tunable optical filter. From the measurements, we have estimated the required equivalent optical bandwidth of our source for an error-free transmission (@ bit-error-rate of $10^{-12}$) and a forward error correction (FEC) threshold of $2{\times}10^{-4}$.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.227-230
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• 2000

Chuas circuit is a simple electronic network which exhibits a variety of bifurcation and attractors. The circuit consists of two capacitors, an inductor, a linear resistor, and a nonlinear resistor. In this paper, a transmitter and a receiver using two identical Chuas circuits are proposed and synchronizations of a equivalent wire and wireless power line are investigated. Since the synchronization of the equivalent wire and wireless system is impossible by coupled synchronization, theory having both the drive-response and the coupled synchronization is proposed. As a result, the chaos synchronization has delay characteristics in the equivalent wire and wireless transmission system caused by the line parameters L and C.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.259-262
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• 2000

Chua's circuit is a simple electronic network which exhibits a variety of bihucation and attractors. The circuit consists of two capacitors, an inductor, a linear resistor, and a nonlinear resistor. In this paper, a transmitter and a receiver using two identical Chua's circuits are proposed anti synchronizations of a equivalent power line are investigated. Since the synchronization of the equivalent power line system is impossible by coupled synchronization, theory having both the drive-response and the coupled synchronization is proposed. Af a result, the chaos synchronization has delay characteristics in the equivalent power line transmission system caused by the line parameters L and C.

• KIEE International Transactions on Power Engineering
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• v.5A no.4
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• pp.350-356
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• 2005

Earth equipments are essential to protect humans and other types of equipment from abnormal conditions. Earth resistance and potential must be restricted within a low value. An estimation algorithm of earth parameters and equivalent resistivity is introduced to calculate reliable earth resistance in this research. The proposed algorithm is based on the relationship between apparent resistances and earth parameters. The proposed algorithm, which approximates the non-linear characteristics of earth by using the Artificial Neural Network (ANN), estimates the earth parameters and equivalent resistivity. The effectiveness of the proposed method is verified with case studies.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.6
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• pp.296-301
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• 2002

Modern power systems are very complex and to model them completely is impractical for electromagnetic transient studies. Therefore areas outside the immediate area of interest must be represented by some form of Frequency Dependent Network Equivalent (FDNE). In this paper a method for developing Frequency Dependent AC system Equivalent (FDACSE) using Z-domain rational Function Fitting is presented and demonstrated. The FDACSE is generated by Linearized Least Squares Fitting(LSF) of the frequency response of a Z-domain formulation. This 1 & 2 port FDACSE have been applied to the New Zealand South Island AC power system. The electromagnetic transient package PSCAD/EMTDC is used to assess the transient response of the 1 & 2 port FDACSE developed under different condition (linear load, fault and nonlinear loading). The study results have indicated the robustness and accuracy of 1 & 2 port FDACSE for electromagnetic transient studies.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.11
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• pp.50-55
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• 2009

In this paper, a distributed amplifier is designed using distributed network synthesis that provides the optimum absorption capability of a capacitance. Transfer functions of filters, which consist of the amplifier, are synthesized by a low-pass Chebyshev approximation. Capacitances that a filter network can absorb are calculated as a function of its minimum insertion loss(MIL) and ripple. Active devices in a distributed amplifier are modeled as equivalent circuits by using their S-parameters, and their equivalent capacitances are absorbed into filter structures by properly adjusting the MIL and ripple of a transfer function. As an application example, a distributed amplifier with the gain of about 12.5dB is designed that operates over the frequency range between 0.1 and 7.5GHz. Experimental results prove that distributed network synthesis, which considers capacitance absorption capability, is useful to the design of distributed amplifiers.

• Journal of Technology Innovation
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• v.27 no.3
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• pp.53-82
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• 2019

This study empirically conduct structural equivalence analysis based on social network analysis in picking up on overall structural characteristics of technological knowledge exchange in a regional cluster. Previous conceptual studies so far have argued that performance differences among structurally equivalent groups exist. However, because little research has been done to empirically investigate this conceptual hypothesis, this study is conducted as complementary to fill this void. For analysis, we utilize two-mode network data consisted of 2,550 firms by investigating 53 technological knowledge exchange-related associations within Gumi national industrial cluster. The results show that some structurally equivalent groups can be defined appropriately and its role can be conditioned by firms' salient characteristics attached to each structural equivalent groups. In addition, it is presented through the present study that performance difference in structural equivalent groups can be distinct by some selected performance indicators. Finally, this study suggests the need to advance the study of performance differences in structurally equivalent groups in the future.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.650-652
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• 2001

The permanent magnet in hybrid step motor is magnetized to the axial direction. Accordingly the 2D analysis method such as 2D finite element method cannot guarantee the analysis accuracy. In this paper, the characteristics of hybrid type step motor are analyzed by using 3D equivalent magnetic circuit network method(3D EMCNM). 3D EMCNM supplements magnetic equivalent circuit by numerical technique using distributive magnetic circuit parameter and 3D EMCNM is used for the accurate and efficient analysis. The validity of the analysis results is confirmed by comparing with the experimental ones.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.147-152
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• 2014

A longitudinal modal transmission-line theory(L-MTLT) to analyze the static and dynamic behavior of two-section distributed feedback (DFB) lasers is used. The characteristic impedance and equivalent propagation constant of DFB structure with active layer are derived from L-MTLT. A two-section DFB laser is analogous to a transmission-line network, in which each section is described by transmission-line block corresponding to the equivalent factors. The longitudinal resonant condition of DFB laser based on equivalent transmission-line network is used to reformulate the rate equations so that static and dynamic behavior of two-section DFB lasers with active layer is demonstrated and analyzed accurately.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.93-102
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• 2004

This paper presents a general theory for the analysis of an aperture-coupled cavity-fed microstrip patch antenna to develop a simple but accurate equivalent circuit model. The developed equivalent circuit consists of ideal transformers, admittance elements, and transmission lines. These circuit element values are computed by applying the complex power concept, the Fourier transform and series representation, and the spectral-domain immittance approach. The input impedance of the antenna is calculated and compared with the published data. Good agreements validate the simplicity and accuracy of the developed equivalent circuit model.