• Journal of Advanced Marine Engineering and Technology
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• 제39권10호
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• pp.1031-1036
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• 2015

Proportional-integral-derivative (PID) controllers are widely used in industrial sites. Most tuning methods for PID controllers use an empirical and experimental approach; thus, the experience and intuition of a designer greatly affect the tuning of the controller. The representative methods include the closed-loop tuning method of Ziegler-Nichols (Z-N), the C-C tuning method, and the Internal Model Control tuning method. There has been considerable research on the tuning of PID controllers for single-input single-output systems but very little for multi-input multi-output systems. It is more difficult to design PID controllers for multi-input multi-output systems than for single-input single-output systems because there are interactive control loops that affect each other. This paper presents a tuning method for the PID controller for a two-input two-output system. The proposed method uses a real-coded genetic algorithm (RCGA) as an optimization tool, which optimizes the PID controller parameters for minimizing the given objective function. Three types of objective functions are selected for the RCGA, and each PID controller parameter is determined accordingly. The performance of the proposed method is compared with that of the Z-N method, and the validity of the proposed method is examined.

• 한국정보통신학회논문지
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• 제17권7호
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• pp.1577-1582
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• 2013

본 논문에서는 수조에서 실험을 통해 획득한 데이터를 이용하여 MIMO (Multi-Input Multi-Output) 수중음향통신의 성능을 분석하였다. 이를 위하여 먼저 여러 송수신 위치에서 채널 전달 특성을 측정하였다. 송신신호는 QPSK (Quadrature Phase Shift Keying)로 변조하였으며, 수신신호는 Zero Forcing 등화기 등을 포함하는 검출기를 거쳐 복원되었다. 실험이 이루어진 수조 환경이 물리적으로 폐쇄된 매우 심한 다중 경로 전달 환경이어서 최대 30~40 ms의 지연 현상이 나타났다. 실험 결과 송신 및 수신 센서가 각각 두 개인 $2{\times}2$ MIMO 시스템을 사용하였을 때 채널 특성으로 인해 비트 오차율이 비교적 크게 나타났지만 SISO (Single-Input Single-Output) 시스템에 비해 약 15% 정도 향상된 성능을 갖는 것을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1537-1543
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• 2014

This paper presents a new DC/AC multilevel converter. This configuration uses single DC sources. The proposed converter has two stages. The first stage is a DC/DC converter that can produce several DC-links in the output. The DC/DC converter is one type of boost converter and uses single inductor. The second stage is a multilevel inverter with several capacitor links. In this paper, one single input multi output DC-DC converter is used in order to voltage balancing on multilevel converter. In addition, as compare to traditional multilevel inverter, presented DC/AC multilevel converter has less on-state voltage drop and conduction losses. Finally, in order to verify the theoretical issues, simulation and experimental results are presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.999-1004
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• 2004

In this study, we identify contribution of structure-borne-noise of vehicle HVAC system using Multi-Dimensional spectral analysis (MDSA) method. Firstly, to identify the applicability of MDSA method, the case of HVAC system was modeled with four input / single output system. The four inputs which is given vibration data is composed of blower, evaporator, heater and duct. The single output is noise data from driver's seat. When the blower motor is operating, we analyze the contributions of four input / single output. As a result of experiment, we identify efficiency of systems modeled with four input / single output through ordinary coherence function (OCF) and multiple coherence function (MCF).

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.985-988
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• 1993

An alternative approach to the design of application-driven fuzzy systems is proposed. A broad class of fuzzy systems applications requires a certain fuzzy partition of the input space while it demands for simple numerical quantities. For this class, a dedicated fuzzy system archictecture is presented and a design strategy is proposed. Both the single-input/single-output and multi-input/multi-output cases are considered. Numerical analysis are complete illustrating several aspects of the proposed framework.

• Journal of Communications and Networks
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• 제10권2호
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• pp.194-203
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• 2008

This paper considers the multi-input multi-output (MIMO) relay channel where multiple antennas are employed by each terminal. Compared to single-input single-output (SISO) relay channels, MIMO relay channels introduce additional degrees of freedom, making the design and analysis of optimal cooperative strategies more complex. In this paper, a partial cooperation strategy that combines transmit-side message splitting and block-Markov encoding is presented. Lower bounds on capacity that improve on a previously proposed non-cooperative lower bound are derived for Gaussian MIMO relay channels.

• 한국소음진동공학회논문집
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• 제17권8호
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• pp.741-746
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• 2007

In this study, transfer path identification and output estimation are simulated by multi-dimension spectral analysis method (MDSA). Multi -input/single-output system give expression the vehicle suspension which each inputs are correlated reciprocally. In case of correlating with inputs, the system needs separating the each input signal by MDSA. Main simulations are about finding effective input by coherent output spectrum and selecting optimal input's number by multiple coherence function. Also, by shielding transfer path of each input, transfer path characteristic is identified in terms of overall integrated contribution level.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.157-157
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• 2000

In the fuzzy control for the multi-variable system, it is difficult to obtain the fuzzy rule. Therefore, the parallel structure of the independent single input-single output fuzzy controller using a pairing between the input and output variable is applied to the multi-variable system. The concept of relative gain matrix is used to obtain the input-output pairs. However, among the input/output variables which are not paired the interactive effects should be taken into account. these mutual coupling of variables affect the control performance. Therefore, for the control system with a strong coupling property, the control performance is sometimes lowered. In this paper, the effect of mutual coupling of variables is considered by tile introduction of a simple compensator. This compensator adjusts the degree of coupling between variables using a neural network. In this proposed neuro-fuzzy controller, the Neural network which is realized by back-propagation algorithm, adjusts the mutual coupling weight between variables.

• 한국통신학회논문지
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• 제35권1C호
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• pp.45-54
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• 2010

이 논문에서는 다중사용자 (multi-user) 다중안테나 (multiple-in multiple-out : MIMO) 시스템을 위한 전송기법을 제안한다. Costa가 증명한 더티페이퍼코딩 (dirty-paper coding: DPC)이론에 따르면 송신기가 수신기의 가우시안 분포를 갖는 간섭 신호를 알고 있는 경우 간섭 신호에 상관 없이 채널 캐패시티를 얻을 수 있음이 알려져 있다. 단독사용자 채널의 경우 간단하며 효율적인 DPC기법들이 알려져 있으나 다중사용자 환경에는 실제 구현하는데 있어 복잡도와 관련해 많은 문제를 가지고 있다. 이 논문에서 우리는 다중사용자 환경에서 송신기에 알려진 갑선신호를 효율적으로 제어할 수 있는 네트워크 채널 행렬 삼각화 (network channel matrix triangulation: NMT)기법을 제안하고자 한다. 제안하는 NMT 알고리즘은 다중사용자 MIMO 채널을 서로 독립된 병렬의 Single-input Single-output (SISO) 채널들로 변환하여 단독사용자 환경을 위해 제안되어 있는 기존 DPC기법들을 다중사용자 환경에서도 사용 가능케 한다. 시뮬레이션 결과를 통해 제안된 알고리즘이 다중사용자 환경의 채널 캐패시티에 거의 접근함을 보일 것이다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.1041-1044
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• 1999

In This paper, we investigated the single step prediction for output responses of chaotic system with multi Input multi output using chaotic neural networks. Since the systems with chaotic characteristics are coupled between internal parameters, the chaotic neural networks is very suitable for output response prediction of chaotic system. To evaluate the performance of the proposed neural network predictor, we adopt for Lorenz attractor with chaotic responses and compare the results with recurrent neural networks. The results demonstrated superior performance on convergence and computation time than the predictor using recurrent neural networks. And we could also see good predictive capability of chaotic neural network predictor.