• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.213-216
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• 2005

The time synchronization method for Multi-band UWB systems is proposed. We analyze the performance in symbol synchronization using a training symbol with two identical halves. The two halves of the training symbol are made identical by transmitting a modulated sequence on the even frequencies, while zeros are used on the odd frequencies.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.17-24
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• 1999

This paper presents a method of ANC for transfonrer noise control utilizing a sproker and microphone pair. In this study, the main focus is on identifying the dynamic characteristics of speaker - amplifier microphone path. This study presents a theoretical method to identify the dynamic characteristics of speaker-microphone pairs. The transfer functions of microphone - speaker pair have been estimated utilizing sequential least square(SLS) algorithm. We identified the estimated transfer function has stable JXlles and zeros in z-plane. This paper also propose an architecture far the noise cancellation to which we applied the estimated transfer function.nction.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1978-1982
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• 2005

In this paper, a linear controller is designed for the longitudinal model of X-33 in TAEM (The Terminal Area Energy Management) phase. The CRA (Characteristic Ratio Assignment) is used as the continuous time design method such that the output response of X-33 control system tracks the reference command. The performance of the proposed controller is evaluated through the step response. Also simulation results show that the initial state of the plant is dominantly affected by the poles and zeros of the plant.

• Journal of Communications and Networks
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• v.7 no.3
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• pp.284-293
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• 2005

A critical issue in applications involving networks of wireless sensors is their ability to synchronize, and mitigate the fading propagation channel effects. Especially when distributed 'slave' sensors (nodes) reach-back to communicate with the 'master' sensor (gateway), low power cooperative schemes are well motivated. Viewing each node as an antenna element in a multi-input multi-output (MIMO) multi-antenna system, we design pilot patterns to estimate the multiple carrier frequency offsets (CFO), and the multiple channels corresponding to each node-gateway link. Our novel pilot scheme consists of non-zero pilot symbols along with zeros, which separate nodes in a time division multiple access (TDMA) fashion, and lead to low complexity schemes because CFO and channel estimators per node are decoupled. The resulting training algorithm is not only suitable for wireless sensor networks, but also for synchronization and channel estimation of single- and multi-carrier MIMO systems. We investigate the performance of our estimators analytically, and with simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11C
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• pp.1037-1043
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• 2006

In this paper, we introduce a two-dimensional modulation code for holographic data storage systems(HDSS), which is a candidate for the next generation data storage system. The two-dimensional(2D) intersymbol interference(ISI) induces higher bit error rate(BER). The balanced number of zeros(dark) and ones(light) in each page reduces inter-page interference(IPI). The code rate is 519. Although the proposed code has higher code rate than other 2D code with rate 4/9, the BER performances of two codes are similar.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.1
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• pp.29-33
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• 2014

This paper proposes an alternate time-switched space-frequency block coding transmission technique for single-carrier modulation with frequency domain equalization. There are two antennas in the transmitter but it still has only a baseband and RF and a switch that alternates between the antennas at every symbol timing. Alternating transmit symbols result in zeros which make maximal ratio receive combining possible in the receiver. Simulation results show that it has better performance than the traditional algorithm at the expense of one additional antenna.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.11
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• pp.1594-1601
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• 2014

In this paper, we propose the LQ servo control method for the automatic train control of urban rail vehicle. Structures of the conventional PID control and LQ servo controller are compared in order to demonstrate the simplicity of the proposed controller which doesn't have zeros of the closed loop systems. The energy consumption is dealt with as an object function to be minimized, which consists of the quadratic performance indices for optimal control with the input of the feedback linearization. The effectiveness of the proposed method is shown by the practical example, compared with the conventional PD controller.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11C
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• pp.1062-1069
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• 2003

This paper presents a new loop shaping technique for design of robust optimal PID controllers in order to satisfy the performance requirements. PID controller can be designed by selecting the suitable weighting factors Q and R. This technique is developed by pushing all two zeros formed by PID controller closely to a larger pole of the second order plant. As a result, a good loop shaping is achieved in the high frequencies region on the Bode plot. For the robust optimal tuning of PID controller for second order system, a new loop shaping procedure is developed via LQR approach.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.59-60
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• 2007

본 논문에서는 선형 비최소위상(NMP, Nonminimum Phase) 시스템에서 특정 조건을 만족하는 복소수 NMP 영점을 가진 시스템에서 언더슈트가 발생함을 보이고자 한다. 먼저 중복 실수 NMP 영점을 갖는 시스템에서의 언더슈트의 크기를 추정한다. 이를 바탕으로 복소수 NMP 영점을 가진 시스템을 중복 실수 NMP 영점을 갖는 시스템과 나머지 시스템의 합으로 보고 언더슈트가 발생하는 복소수 NMP 영점의 범위를 구한다. 최종적으로 복소수 NMP 영점의 복소수 항이 특정 제시되는 값보다 작을 때 언더슈트가 발생함을 보인다.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.185-189
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• 1987

An analysis and design of large-scale linear multivariable systems often requires to be block triangularized form for good sensitivity of the systems when their poles and zeros are varied. But the decomposition algorithms presented up to now need a procedure of permutation, rescaling and a solution of nonlinear algebraic equations, which are usually burden. To avoid these problem, in this paper we develop a newly alternative block triangular decomposition algorithm which used the generalized matrix sign function on the Z-plane. Also, the decomposition algorithm demonstrated using the fifth order linear model of a distillation tower system.