• 한국자동차공학회논문집
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• 제22권2호
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• pp.182-189
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• 2014

This paper proposes a decoupler design method to reduce interaction between exhaust gas recirculation (EGR) and variable geometry turbocharger (VGT) systems in passenger car diesel engines. The EGR valve and VGT vane are respectively used to control air-to-fuel ratio (AFR) of exhaust gas and intake pressure. A plant model for EGR and VGT systems is defined by a first order transfer function plus time-delay model, and the loop interaction between these systems is analyzed using a relative normalized gain array (RNGA) method. In order to deal with the loop interaction, a design method for simplified decoupler is applied to this study. Feedback control algorithms for AFR and intake pressure are composed of a compensator using PID control method and a prefilter. The proposed decoupler is evaluated through engine experiment, and the results successfully showed that the loop interaction between EGR and VGT systems can be reduced by using the proposed decoupler. Furthermore, it presents stable performance even off from the designed operating point.

• 한국자동차공학회논문집
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• 제14권5호
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• pp.93-99
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• 2006

Flexible couplers are widely used for exhaust transmitted vibration reduction in vehicles. This paper describes an investigation into the acoustical characteristics of exhaust flexible coupler by the simulation and testing. Computational acoustic simulation is carrying out to investigate resonance frequency and transmission loss of decoupler using the boundary element method and transfer matrix approach. To confirm the acoustical simulation results of exhaust decoupler, we compare with measured experimental results by the test of transmission loss measurement system. In the comparison with simulation results and tests results, there is correctly fit the resonance frequency and the trend of transmission loss. Also, we show that the acoustical structure of decoupler is analogous to the expended tube or side branch resonator. The characteristics of exhaust decoupler have a marked increase in the acoustic attenuation at the specified frequency bend. Therefore the decoupler is applied to develop the exhaust system not only for the vibration isolator but also for the noise attenuator.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.39-39
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• 2000

In this paper, a decoupler of tandem cold rolling mill is designed. Before designing the decoupler, this paper improved conventional linear model by considering friction and yield stress of rolling strip. In a stand, the decoupler let an output be controlled by an input. And even if states of other stands should be changed, current stand takes no interference from those changes. In addition, with the same method, a feedforward controller is designed for an input strip thickness error. Finally, performance of controllers above is shown with nonlinear simulation.

• International Journal of Aeronautical and Space Sciences
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• 제18권2호
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• pp.378-387
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• 2017

The combined model following control (MFC)-decoupler system is employed for a full authority fly-by-wire utility helicopter to enhance handling qualities. The MFC, which governs the vehicle to follow the prescribed model, is widely employed for modern helicopters. However, it may not be sufficient as helicopters often suffer significant cross coupling. The coupled responses between control axes of a helicopter increase the pilot's work load and may degrade handling qualities. As the decoupler is introduced to the MFC, the combined MFC-decoupler effectively solves the coupling problems and enhances handling qualities. The proposed system is verified via the handling qualities prediction using the mathematical dynamics model. The analysis results are confirmed through the piloted simulation.

• 한국자동차공학회논문집
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• 제14권3호
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• pp.157-163
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• 2006

This paper described the process of improving durability performance of the exhaust decoupler by the plasma nitriding. The properties of plasma nitriding treatment of AIS1304 stainless steel were tested using specimens before applying plasma nitriding to a mesh ring. In order to analyses the effect of plasma nitriding treatment on the mechanical properties, SEM(Scanning Electron Microscopes), roughness and hardness tester were used. Based on specimen plasma nitriding, we could find appropriate condition for application to the mesh ring of decoupler. To confirm the improved durability performance, we compared the number of cycles, which reaches to fracture, of the nitrided decoupler and that of the unnitrided decoupler by the bending cyclic test. In this test, the durability and wear resistance of the mesh ring are significantly improved by plasma nitriding treatment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.244-246
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• 2005

The Tonpiltz transducer is one of the essential elements in sonar application. The characteristics of transducer depend on the piezoelectric ceramics and mechanical elements such as head mass, tail mass, pre-stress rod and so on. One of the important characteristics is stable electric resistance for high power transmitting operation. This paper presents characteristics variation of the underwater acoustic transducer with material variation of electric decoupler.

• 한국소음진동공학회논문집
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• 제27권1호
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• pp.80-86
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• 2017

This paper describes switching method of the cross-sectional area of the fluid passage way to improve the performance of a hydraulic engine mount with an inertia track and a decoupler. The mount has nonlinear dynamic characteristics depending on the vibrational frequency and amplitude. For the convenience of analysis, two linear motion equations were derived on the basis of the mechanical model according to the low-and high-frequencies. The properties of the transmissibility and dynamic stiffness derived from the equations were investigated according to switching the cross-sectional area of the inertia track and decoupler. Switching method of the cross-sectional area can be derived from the transmissibility plot. In comparison between transmissibility of passive and switchable mounts with an inertia track and a decoupler, the performance of the switchable mount is improved greatly than the passive mount. The resonant peak is remarkably reduced in the high frequency region.

• 정보저장시스템학회논문집
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• 제3권2호
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• pp.59-65
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• 2007

Scanning Prove Microscope (SPM) - based Data Storage (SDS)는 Atomic Force Microscope (AFM)을 이용하여 Cantilever Tip 이 저장 장치 미디어에 나노미터 단위로 비트를 읽고, 쓰고 지우는 저장 장치로써, x, y 두 축을 이용한다. 따라서 축간 coupling 의 영향이 크게 발생한다. 따라서 축간 coupling 의 영향을 고려하여 제어기를 설계하여야 한다. 본 논문은 coupling 요소를 제거하기 위하여 Feedforward Decoupler 를 설계하여 Stage 의 입력 앞 단에 추가하는 방법을 제안하였다. Feedforward Decoupler 를 추가함으로써 coupling 요소가 줄어드는 것을 모의 실험을 통해 확인한다. 이를 통해 나노급으로 보다 정밀한 제어가 가능함을 확인하였다.

• 한국ITS학회 논문지
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• 제13권2호
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• pp.50-56
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• 2014

본 논문에서는 LTE 700MHz(Band12, 13, 14, 17, 28, 44) 대역에서 동작 가능한 4개의 포트를 가진 펨토셀(Femtocell) MIMO 안테나를 설계 제작하였다. 마이크로스트립 패치 안테나를 기반으로 임피던스 매칭을 위하여 쇼트핀을 이용하였고, 한정된 크기에서 충분한 안테나 격리도를 얻기 위해 십자형 디커플러를 이용하였다. 시뮬레이션에 의한 최적화된 파라미터를 가지고 제작하였으며, 제작된 안테나는 VSWR${\leq}2$에서 105MHz(0.698~0.803) 대역폭을 만족하고 1.97dBi의 이득과 격리도는 13dB이상의 값을 얻었다. MIMO 안테나의 성능을 판단하는 주요 파라미터인 안테나간 상관계수는 0.2 이하의 결과를 얻었다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1996년도 영남지부 학술발표회 논문집 Acoustic Society of Korean Youngnam Chapter Symposium Proceedings
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• pp.46-50
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• 1996