• Journal of Korea Society of Industrial Information Systems
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• v.20 no.1
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• pp.49-55
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• 2015

This paper proposes a 2.4 GHz RF oscillator with a very low close-in phase noise performance. This is composed of a low frequency crystal oscillator and three frequency multipliers such as two doubler (X2) and one tripler (X3). The proposed oscillator is implemented as a hybrid type circuit design using a discrete silicon bipolar transistor. The measurement results of the proposed oscillator structure show -115 dBc/Hz close-in phase noise at 10 kHz offset frequency, while only dissipating 5 mW from a 1-V supply. Its close-in phase noise level is very close to that of a low frequency crystal oscillator with little degradation of noise performance. The proposed structure which is consisted of a low frequency crystal oscillator and a frequency multiplier provides new method to implement a low power low close-in phase noise RF local oscillator.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.6
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• pp.435-441
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• 2003

This paper addresses that an approximation and tracking control of realtime recurrent neural networks(RTRN) using two-dimensional iterative teaming algorithm for an electro-hydraulic servo system. Two dimensional learning rule is driven in the discrete system which consists of nonlinear output fuction and linear input. In order to control the trajectory of position, two RTRN with the same network architecture were used. Simulation results show that two RTRN using 2-D learning algorithm are able to approximate the plant output and desired trajectory to a very high degree of a accuracy respectively and the control algorithm using two identical RTRN was very effective to trajectory tracking of the electro-hydraulic servo system.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.2
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• pp.157-163
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• 2005

In this paper, we present the multimodal system based on the fusion of two user-friendly biometric modalities: Iris and Face. In order to reach robust identification and verification we are going to combine two different biometric features. we specifically apply 2-D discrete wavelet transform to extract the feature sets of low dimensionality from iris and face. And then to obtain Reduced Joint Feature Vector(RJFV) from these feature sets, Direct Linear Discriminant Analysis (DLDA) is used in our multimodal system. In addition, the Synergetic Neural Network(SNN) is used to obtain matching score of the preprocessed data. This system can operate in two modes: to identify a particular person or to verify a person's claimed identity. Our results for both cases show that the proposed method leads to a reliable person authentication system.

• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.1
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• pp.1-9
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• 2004

This paper addresses an approximation and tracking control of recurrent neural networks(RNN) using two-dimensional iterative learning algorithm for an electro-hydraulic servo system. And two dimensional learning rule is driven in the discrete system which consists of nonlinear output function and linear input. In order to control the trajectory of position, two RNN's with the same network architecture were used. Simulation results show that two RNN's using 2-D learning algorithm are able to approximate the plant output and desired trajectory to a very high degree of a accuracy respectively and the control algorithm using two same RNN was very effective to control trajectory tracking of electro-hydraulic servo system.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1492-1495
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• 2005

This paper presents a new linear-matrix-inequality-based intelligent digital redesign (LMI-based IDR) technique to match the states of the analog and the digital T-S fuzzy control systems at the intersampling instants as well as the sampling ones. The main features of the proposed technique are: 1) the affine control scheme is employed to increase the degree of freedom; 2) the fuzzy-model-based periodic control is employed; and the control input is changed n times during one sampling period; 3) The proposed IDR technique is based on the approximately discretized version of the T-S fuzzy system; but its discretization error vanishes as n approaches the infinity. 4) some sufficient conditions involved in the state matching and the stability of the closed-loop discrete-time system can be formulated in the LMIs format.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.1
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• pp.34-40
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• 1998

For applicating to 10-Gbit/s optical transimission systems, we have designed and fabricated a laser driver IC with extremely-high-operation-frequencies using AlGaAs/GaAs heterojunction bipolar transistors (HBTs), and have investigated its performances. Circuits design andsimulation were performed using SPICE and LIBRA. A discrete AlGaAs/GaAs HBT with the emitter area of 1.5*10 .mu.m$^{2}$, used for the circuit fabrication, exhibited cutoff frequency of 63 GHz andmaximum osciallation frquency of 50 GHZ. After fabrication of MMICs, we observed the very wide bandwidth of DC~18 GHz and the S$_{21}$ gain of 17 dB for a laser driver IC from the on-wafer measurement. Metal-packaged laser driver IC showed the excellent eye opening, the modulation currents of 32 mA, the rise/fall time of 40 ps, measured at the data rates of 10-Gbit/s.

• Journal of Korea Multimedia Society
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• v.8 no.5
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• pp.670-678
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• 2005

A Cellular Automaton(CA) is a dynamical system in which space and time are discrete, the state of each cell is unite and is updated by local interaction. Since the characteristics of CA is diffusion and local interaction, CA is used by crypto-systems and VLSI structure. In this study, we proposed a hash function based on the concept of 2-dimensional cellular automata and analyzed the proposed hash function.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.260-268
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• 2013

Based on classical Berotti discrete iron loss calculation model, the iron loss analysis mathematical model of alternator was proposed in this paper. Considering characteristics of high speed and changing frequency of the alternator, Maxwell 3-D model was built to analyze iron loss corresponding to each running speed in alternator. Based on iron loss model of alternator at rated speed, the rotor claw pole size was made an optimization design. The optimization results showed that alternator's output performance had been improved. A new idea was explored in size optimization design of claw pole alternator.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.1
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• pp.124-131
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• 1997

There have been many demands for th ereal-time image compression. The image compression systems have a wide range of applications. However, real-time encoding is hard to implement because it needs a large amount of computations. In particular, the discrete cosine transform (DCT) and motion estimatio require a large number of arithmetic oeprations compared to other algorithms in MPEG-2. The conventional fasdt DCT algorithms have focused on the reduction of the number of additions more cycles and more expense in realization. Because TMS320C80 has special structure, new approach for implementation of DCT is suggested. The selection of adaptive algorithm and optimization is requried TMS320C80 are analyzed an dsome adaptive DCT algorithms are selected. The DCT algorithms are optimized and implemented. Chens and lees DCT algorithms among various fast algorithms are selected because 1-D approach is effective in the view of th einternal structure of TMS320C80. According to the simulation result, Lees algorithm is more effective in speed and has little difference in precision. On the basis of the result, the possibility of DCT implementation for real-time MPEG-2 system is verified and the required number of the processor, called advanced DSP, is decided for real-time MPEG-2 encoding and decoding.

• Economic and Environmental Geology
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• v.49 no.1
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• pp.31-41
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• 2016

A program code was developed to calculate block hydraulic conductivity of the 2-D DFN(discrete fracture network) system based on equivalent pipe network, and implemented to examine the effect of joint orientation distribution on the hydraulic characteristics of fractured rock masses through numerical experiments. A rock block of size $32m{\times}32m$ was used to generate the DFN systems using two joint sets with fixed input parameters of joint frequency and gamma distributed joint size, and various normal distributed joint trend. DFN blocks of size $20m{\times}20m$ were selected from center of the $32m{\times}32m$ blocks to avoid boundary effect. Twelve fluid flow directions were chosen every $30^{\circ}$ starting at $0^{\circ}$. The directional block conductivity including the theoretical block conductivity, principal conductivity tensor and average block conductivity were estimated for generated 180 2-D DFN blocks. The effect of joint orientation distribution on block hydraulic conductivity and chance for the equivalent continuum behavior of the 2-D DFN system were found to increase with the decrease of mean intersection angle of the two joint sets. The effect of variability of joint orientation on block hydraulic conductivity could not be ignored for the DFN having low intersection angle between two joint sets.