• International Journal of Aeronautical and Space Sciences
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• 제17권3호
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• pp.442-453
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• 2016

A significant source of vibration in helicopters is the main rotor system, and it is a technical challenge to reduce the vibration in order to ensure the comfort of crew and passengers. Several types of passive devices have been applied to conventional helicopters in order to reduce the vibration. In recent years, helicopter manufacturers have increasingly adopted active vibration control systems (AVCSs) due to their superior performance with lower weight compared with passive devices. AVCSs can also maintain their performance over aircraft configuration and flight condition changes. As part of the development of AVCS software for light civil helicopter (LCH) applications, a test bench is constructed and vibration control tests and simulations are performed in this study. The test bench, which represents the airframe, is excited using a pair of counter rotating force generators (CRFGs) and a multiple input single output (MISO) AVCS that consists of three accelerometer sensors and a pair of CRFGs; a filtered-x least mean square (LMS) algorithm is applied for the vibration reduction. First, the vibration control tests are performed with uniform sensor weights; then, the change in the control performance according to changes in the sensor weight is investigated and compared with the simulation results. It is found that the vibration control performance can be tuned through adjusting the weights of the three sensors, even if only one actuator is used.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.480-483
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• 2018

본 논문에서는 CMOS센서 기반 가시광 통신 시스템에서 고속전송을 위한 다중 광원의 간섭제거 및 이미지 센싱 처리기술에 대해서 연구하였다. 이미지센서를 통한 광학카메라 통신에서 전송 용량을 향상 시키려면 각 LED에서 다른 데이터를 동시에 전송해야한다. 그러나 고속전송을 위한 다수의 LED광원 환경은 인접한 LED 간 간섭을 일으킬 수 있다. 이 경우, 가시광통신시스템은 일반적으로 세기 변조를 사용하기 때문에 다수의 LED가 동시에 데이터를 전송할 경우 인접한 LED의 빛 퍼짐 간섭으로 인해 각각의 LED들의 정확한 신호 검출이 어렵다. 이러한 문제를 해결하기 위해서, 듀얼 CMOS 센서를 사용하여 다수의 광원 LED의 ON/OFF 상태를 정확히 인식하고, 각각의 LED들의 이미지 시그널 프로세싱 기법을 제안하였다. 이러한 기법을 통해 다수의 LED픽셀을 정확하게 인식하여 다중LED OCVLC 시스템의 총 평균 비트 오류율과 처리량을 향상시킬 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2249-2251
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• 2001

This paper proposes that it minimizes interference between link at high speed trajectory tracking of 2-degree parallel link manipulator and QFT(Quantitative Feedback Theory) controller which robust structure uncertainty and disturbance of plant. And using ICD(Individual Channel Design), it separates two channel from multivariable system, parallel link manipulator and designs robust controller with applying MISO QFT to each channel. Finally, we make sure of robustness and excellence of QFT controller through simulation and experiment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.137-140
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• 1999

A lot of researcher have proposed a method of kernel identifying nonlinear system by use of Wiener kernels[6-7] or Volterra kernel[5] and so on. In this research, the authors proposed a method of identifying Volterra kernels for nonlinear system by use of pseudorandom M-sequence in which a crosscorrelation function between input and output of a nonlinear system is taken[4]. we can be applied to an MISO nonlinear system or a system which depends on its input amplitude[2]. But, there exist many systems in which it is difficult to determine a Volterra kernel having the same time coordinate on the crosscorrelation function. In those cases, we have to estimate Volterra kernel by using its neighboring points[4]. In this paper, we propose a new method for not estimating but obtaining Volterra kernel having the same time coordinate using calculation between the neighboring points. Some numerical simulations show that this method is effective for obtaining higher order Volterra kernel of nonlinear control systems.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권1호
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• pp.50-55
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• 2004

We propose an intgrated Gill environment system having only integer fuzzy operations in the consequent part and the defuzzification stage. In this paper, we also propose an integrated Gill environment system with 4 parallel fuzzy processing units to be operated in parallel on the classification of the sensed image data. In this, we solve the problems of taking longer times as the fuzzy real computations of [0, 1] by using the integer pixel conversion algorithm to convert lines of each fuzzy linguistic term to the closest integer pixels. This procedure is performed automatically in the GUI application program. As a Gill environment, PCI transmission, image data pre-processing, integer pixel mapping and fuzzy membership tuning are considered. This system can be operated in parallel manner for MIMO or MISO systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.1889-1910
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• 2017

This paper investigates a protocol so-called Adaptive Harvest Then Transmit (AHTT) for wireless powered communication networks (WPCNs) in multiple-input single-output (MISO) downlink systems, which assists in transmitting signals from a multi-antenna transmitter to a single-antenna receiver. Particularly, the power constrained relay is supplied with power by utilizing radio frequency (RF) signals from the source. In order to take advantage of multiple antennas, two different linear processing schemes, including Maximum Ratio Combining (MRC) and Selection Combination (SC) are studied. The system outage capacity and ergodic capacity are evaluated for performance analysis. Furthermore, the optimal power allocation is also considered. Our numerical and simulation results prove that the implementation of multiple antennas helps boost the energy harvesting capability. Therefore, this paper puts forward a new way to the energy efficiency (EE) enhancement, which contributes to better system performance.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.18-19
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• 2020

Domestic and foreign high-rise buildings are expected to continue to increase in the future. In addition, recently, residents and landlords are demanding maintenance necessary to secure the performance of sustainable buildings, so an effective management plan is needed. Therefore, this study aims to develop customized technologies that can be effectively applied to building structures by comprehensively analyzing existing technology-based research cases. As a result, it is expected that this will serve as a stepping stone to present a s+ample of future technology development along with a reduction in labor dependency on maintenance and quality improvement.

• 대한기계학회논문집A
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• 제32권3호
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• pp.280-289
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• 2008

This paper presents design of the quantitative feedback control system of the three axes hydraulic road simulator with respect to the dummy wheel for uncertain multiple input-output(MIMO) feedback systems. This simulator has the uncertain parameters such as fluid compressibility, fluid leakage, electrical servo components and nonlinear mechanical connections. This works have reproduced the random input signal to implement the real road vibration's data in the lab. The replaced $m^2$ MISO equivalent control systems satisfied the design specifications of the original $m^*m$ MIMO control system and developed the mathematical method using quantitative feedback theory based on schauder's fixed point theorem. This control system illustrates a tracking performance of the closed-loop controller with low order transfer function G(s) and pre-filter F(s) having the minimum bandwidth for parameters of uncertain plant. The efficacy of the designed controller is verified through the dynamic simulation with combined hydraulic model and Adams simulator model. The Matlab simulation results to connect with Adams simulator model show that the proposed control technique works well under uncertain hydraulic plant system. The designed control system has satisfied robust performance with stability bounds, tracking bounds and disturbance. The Hydraulic road simulator consists of the specimen, hydraulic pump, servo valve, hydraulic actuator and its control equipments

• 한국통신학회논문지
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• 제37권3A호
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• pp.135-140
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• 2012

이 논문은 순환 지연 다이버시티 OFDM 시스템의 성능을 향상시키기 위하여 주파수 다이버시티를 적용하는 알고리즘을 제안한다. OFDM 시스템에서 주파수 다이버시티 적용은 동일한 심볼을 상관관계가 없는 부반송파로 반복 전송하는 것으로 수행되며, 반복 전송 회수에 비례하여 변조 레벨을 증가시켜서 종래의 전송 시스템의 성능과 비교한다. 이 방법은 순환 지연 다이버시티 알고리즘과 같이 송신기 개수가 많아짐에 따라 수신기에서 부가적인 특별한 하드웨어가 필요하지 않다는 동일한 장점이 있게 되며, 성능 시험을 위해서 다중 송수신 안테나 환경하에서 모의 실험을 수행하였다. 제안하는 알고리즘은 종래의 순환 지연 다이버시티를 활용한 OFDM 시스템과 비교하여 저밀도 변조 레벨에서 성능 향상이 현저함을 보여준다.

• 한국버섯학회지
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• 제7권4호
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• pp.141-149
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• 2009

본 연구는 신품종 '미소' 느타리버섯에 대한 성양식에서의 불화합성 체계를 이해하고자 수행하였으며 이 실험결과 자실체로부터 채취한 단포자의 교배를 통해 신품종 '미소' 느타리버섯이 자웅이체성이고 4극성 교배양식을 나타내는 것을 확인하였다. 꺽쇠연결이 없는 분리된 담자포자는 단핵균사로 판단되었고, 이러한 단핵균사간 화합, 불화합성 여부는 빠른 생육과 활력있는 발달형태를 통해 어느 정도 육안으로도 확인이 가능하였으며 두 단핵 균사체의 대치배양 후에 형성되는 꺽쇠연결을 현미경으로 관찰하여 명확히 확인되었다. 예외적으로 교배가 화합성인 경우 형성되는 이핵 균사체가 대치배양의 한쪽 가장자리에서만 꺽쇠연결이 발견되는 일방향 이핵화 현상이 관찰되었다. 이 실험결과로부터 4극성 교배에 있어서 $A_1A_2B_1B_2$의 이핵 균사체로부터 발생하는 네 가지 유전자 형태, 즉 $A_1B_1$, $A_1B_2$, $A_2B_1$, 그리고 $A_2B_2$가 화합성 테스트에 의해 결정되었으며 선발된 나머지의 단핵 균사체의 교배형은 Tester 계통을 이용하였다.