• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.5
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• pp.440-449
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• 2014

This study proposes an LLC series resonant converter with a current doubler using a coupled inductor as a rectification circuit for the secondary side. The current doubler circuit is generally used for a high-voltage input and low-voltage output circuit to obtain high efficiency with small transformer turn ratio. However, an inductive circuit is not generally used in the secondary side of an LLC series resonant converter. If inductive components exist on the secondary side, the resonant characteristics are changed through the secondary inductive circuit. Mathematical analysis shows that the secondary-side current doubler with coupled inductor is not affected by the resonant characteristic of the primary LLC if leakage inductance occurs in the coupled inductor. Results of the analysis are proven by simulation; an experiment is also conducted for the proposed circuit.

• Journal of the Korean Institute of Telematics and Electronics
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• v.9 no.2
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• pp.1-16
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• 1972

In this paper, the characteristics of linearly tapered strip-line filters, where the even-mode and odd-mode characteristic impedances vary linearly with the same degree along the lines, are analyzed. The Impedance parameters of linearly tapered coupled strip-line, which is made by connecting two linearly tapered unsymmetric coupled strip-lines In cascade and the I:no input and output terminals are made equal, are obtained. Using the above parameters, the Image parameters of linearly tapered coupled strip-line filters are derived. The result of analysis shows that the line length can be made shorter and also the stop-band width between the fundamental and second pass-band becomes wider, compared with the coupled strip-line filters which use uniform strip-lines. Furthermore, the difference of impedance levels in the fundsmental and second pass-band becomes larger with the degree of taper of the lines. This property is unique, in comparison with the case of uniform or exponentially tapered strip-line filters.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1728-1735
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• 1989

A design procedure for microstrip bandpass filters using step impedance resonators (SIR's) and tapped input/output to a conventional parallel coupled line bandpass filter is presented. The filter configuration consisting of both half-wavelength and SIR's suppreses to spurious resonance response near the second harmonics, while tapping techniques offer benefit in situations where the impractical. The measured frequency responses of the designed filter are in close agreement with the computed responses.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.4
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• pp.7-13
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• 1998

The gloval model is developed by combining this actuator formular with robot manipulator which is reported previously . The model initially represented in the form of coupled time-varying nonlinear dynamic system. It then decomposed into the decoupled linear model using nonlinear feedback and state transformation techniques. The new model employes the pole replacement method to improve the stability of the system. Using this new model, an robust control algorithm is developed. The proposed algorithm takes two state variables, position vector and velocity vector, and one input variable from actuator, input voltage.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.7
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• pp.82-88
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• 1992

This paper presents one of the first comprehensive studies of how hot electron degradation impacts the input offset voltage of a CMOS differential amplifiers. This study utilizes the concept of a virtual source-coupled MOSFET pair in order to evaluate offset voltaged egradation directly from individual device measurement. Next, analytical models are developed to describe the offset voltage degradation. These models are used to examine how hot electron induced offset voltage is affected with the device parameters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.10
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• pp.2028-2042
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• 1994

Properly defining signal and noise in a self-organizing system like ART(Adaptive Resonance Theory) neural network model raises a number of subtle issues. Pattern context must enter the definition so that input features, treated as irrelevant noise when they are embedded in a given input pattern, may be treated as informative signals when they are embedded in a different input pattern. The ATR automatically self-scales their computational units to embody context and learning dependent definitions of a signal and noise and there is no problem in categorizing input pattern that have features similar in nature. However, when we have imput patterns that have features that are different in size and nature, the use of only one vigilance parameter is not enough to differentiate a signal from noise for a good categorization. For example, if the value fo vigilance parameter is large, then noise may be processed as an informative signal and unnecessary categories are generated: and if the value of vigilance parameter is small, an informative signal may be ignored and treated as noise. Hence it is no easy to achieve a good pattern categorization. To overcome such problems, a Coupled-ART neural network capable of modularized categorization of patterns is proposed. The Coupled-ART has two layer of tightly coupled modules. the upper and the lower. The lower layer processes the global features of a pattern and the structural features, separately in parallel. The upper layer combines the categorized outputs from the lower layer and categorizes the combined output, Hence, due to the modularized categorization of patterns, the Coupled-ART classifies patterns more efficiently than the ART1 model.

• ETRI Journal
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• v.40 no.3
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• pp.303-308
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• 2018

This paper proposes a simple yet accurate method for estimating the antenna correlation coefficient (ACC) of a high-order multiple-input multiple-output (MIMO) antenna. The conventional method employed to obtain the ACC from three-dimensional radiation patterns is costly and difficult to measure. An alternate method is to use the S-parameters, which can be easily measured using a network analyzer. However, this method assumes that the antennas are highly efficient, and it is therefore not suitable for lossy MIMO antenna arrays. To overcome this limitation, we define and utilize the non-coupled radiation efficiency in the S-parameter-based ACC formula. The accuracy of the proposed method is verified by the simulation results of a 4-port highly coupled lossy MIMO array. Further, the proposed method can be applied to N-port arrays by expanding the calculation matrix.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.25-26
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• 2011

In some cases of grid connected system using photovoltaic modules, high voltage step up ratio is required. In this paper, non-isolated 2-stage cascaded boost converter with coupled inductor is proposed. Due to reduce the input current ripple and size of the inductor by using coupled inductor method, this topology is suitable for MIC(Module Integrated Converter). The operational characteristic of the proposed topology is verified through the theorical analysis, simulation and experimental waveform.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.10
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• pp.842-846
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• 2002

Design of gas concentration process using a fully thermally coupled distillation is conducted with the commercial design software HYSYS. Detailed procedure of the design is explained, and the performance of the process is compared with that of a conventional system A structural design is exercised for the design convenience. The design outcome indicates that the procedure is simple and efficient. The structural information yielded from equilibrium distillation gives an easy formulation of distillation system which is the initial input required from the setup of the distillation system The performance of the new process indicates that an energy saving of 17.6 % is obtained compared with the conventional process while total number of trays maintains at the same.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.1
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• pp.20-23
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• 2004

In this paper, the emission properties of electrodeless fluorescent lamp were discussed using the inductively coupled plasma. To transmit the electromagnetic energy into the chamber, a RF power of 13.56 [MHz] was applied to the antenna and considering the Ar gas pressure and the RF electric power change, the emission spectrum, Ar I line, luminance were investigated. At this time, the input parameter for ICP RF plasma, Ar gas pressure and RF power were applied in the range of 10∼60 [mTorr], 10∼300 [W], respectively. From emission intensity and lumnance intensity results, the mode transition from E-mode to H-mode was observed. This implies that this method can be used to find an optimal RF power for efficient light illumination in an electrodeless fluorescent lamp.