• 한국재난정보학회 논문집
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• 제19권1호
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• pp.10-17
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• 2023

연구목적: 본 논문에서는 IR-UWB를 활용하여 실내 위치 추정을 위한 거리 추정 기술을 제안하고 연구 수행한다. 실내 환경에서 clutter(클러터)나 noise(노이즈) 환경으로 인해 낮아진 목표 신호의 검출과 세기를 높일 수 있는 알고리즘을 제안한다. 연구방법: 클러터 억제와 미약 신호를 검출하기 위해 기존 연구인 Background Remover, Corelation, Singular Vector Decomposition 연구를 분석하고 알고리즘을 제안한다. 알고리즘의 평가를 위해 일반 실내 건물에서 2~11.5m 까지 목표물을 측정하는 실험을 진행하고 평균 에러율을 통해 성능평가 및 검증을 진행한다. 연구결과: 제안하는 알고리즘을 통해 11.5m까지 평균에러 0.57m, 6m이상에서 11.5m까지 에러율 0.49m였다. 기존 연구 대비하여 평균 에러율 약 1m를 줄이는 결과를 보였다. 결론: 본 연구에서 제안하는 알고리즘을 실험을 통해 검증했다. 거리나 위치 추정을 위한 클러터, 노이즈 환경에서 미약 신호 검출하는 기법으로 활용이 가능할 뿐 아니라 투과성이 높은 UWB 레이더를 활용하여 제난 상황에서 인명을 피해를 줄이기 위한 인명 검출 기법으로 활용될 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1700-1703
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• 1997

The flexibility of the manipulator inevitably inducess the vibration at the end effector. For the increase in speed and accuracy at the end tip, in this work, position and vibration control of a flexible manipuator with a separate voice coil type actrator for vibration suppression, is studied. The flexible manipulator with a tip mass is modeled an Euler-Bernoulli beam. An H.inf. controller is designed in order to make the controlled system robust against unmodeled higher-order mode vibration of the manipulator, output sensor noise, and etc. Simulations and experiments show that the modeling of the system is valid and that robust vibration control of the flexible manipulator is efficiently achieved.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2000년도 하계학술발표대회 논문집 제19권 1호
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• pp.47-50
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• 2000

비상관적인 가산잡음에 오염된 음성으로부터 향상된 음성을 얻기 위한 방법 중 Soft Decision에 근거한 음성 향상 기법이 뛰어난 성능을 가진다고 알려져 있다. Soft Decision은 주파수 영역에서 음성에 가산된 잡음을 처리하며, 잡음 환경에 대한 사전정보에 의존적이다. 본 연구에서는 Soft Decision을 근거로 음성에 가산된 잡음신호를 비선형 처리를 하여 효과적으로 음성에 포함된 잡음을 추정하도록 하였으며, 잡음환경에 대한 사전 정보 없이 효율적으로 잡음을 억제하는 방법을 제안한다. 본 연구에서 제안한 음성향상 기법은 주관적인 음질평가에서 기존의 방법들보다 나은 성능을 나타내었다

• 소음진동
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• 제7권6호
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• pp.1007-1013
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• 1997

This paper presents active vibration control scheme of multi-mode forced vibration using piezocetamic sensors and actuators. The control scheme adopted is the Positive Position Feedback (PPF) control. Among various vibration control techniques. PPF control technique makes use of generalized displacement measurements to accomplish the vibration suppression. Two independent controllers are implemented to control the first and the second modes of the beam under external excitation. Experimental results for various damping ratios and feedback gains of the PPF controllers are compared with respect to the contorl efficiency. The results indicate that steady state vibration under wide band excitation can be controlled effectively when multiple sets of PZT sensors and actuators were used with PPF control technique.

• 소음진동
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• 제8권6호
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• pp.1121-1129
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• 1998

This research is concerned with the multiple PPF and the modified LQG controller design for active vibration control of intelligent structures. The intelligent structure is defined as the structure equipped with smart actuators and sensors. Various control techniques aimed for the piezoceramic sensors and actuators have been proposed for the active vibration control of smart structures and some of them prove their effectiveness experimentally. In this paper, the multiple PPF controller and the modified LQG controller are developed and applied to the smart grid structure. The multiple PPF control and the modified LQG control can be classified as the classical and the modern control techniques. respectively. The experimental results show that both control techniques are effective in suppressing vibrations. Two control techniques are compared with respect to the design process. the ease of implementation and the effectiveness

• 소음진동
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• 제11권2호
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• pp.292-300
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• 2001

This research is concerned with the validation of the modeling technique and controller design for slewing beam structures. When cantilever beam rotates about axes perpendicular to the undeformed beam's longitudinal axis, it experiences inertial loading. Hence, the beam vibrates from the initial stage of slewing. In this paper, the analytical model for a single slewing flexible beam with surface bonded piezoelectric sensor and actuator is developed using the Hamilton's principle with discretization by the assumed mode method. Comparisons with the theoretical model are made based upon the frequency responses and time responses. A new factor called the coupling coefficient is introduced to incorporate the discrepancies between the theoretical and experimental results. The slewing is achieved by applying the PID control, which is found to be less sensitive to vibrations. The vibrations are controlled by PPF controller, which is found to be effective in suppressing residual vibrations after slewing. The vibrations occurred during slewing is difficult to control because the piezoceramic actuator is not powerful enough to overcome inertial loadings.

• 소음진동
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• 제7권3호
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• pp.387-392
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• 1997

This paper concerns a SCARA robot with the flexible forearm linked to the rigid upper arm. The equations of motion are derived by the Lagrangian mechanics. For controller design, the perturbation approach is taken to separate the original equations of motion into linear equations describing small perturbed motions and nonlinear equations describing purely rigid motion of the robot. To effect the desired payload motion, open loop control inputs are determined based on the inverse dynamics of the latter. In order to reduce the positional error during maneuver, an active vibration suppression is done. To this end, a feedback control is designed for robustness against disturbance on the basis of the linear equations and the LQR theory modified to have a prescribed degree of stability. The proposed control scheme shows satisfactory performances in experiments as well as in numerical simulations.

• 한국정보전자통신기술학회논문지
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• 제1권1호
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• pp.21-27
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• 2008

본 논문에서는 개인용 컴퓨터를 기반으로 한 실시간 마이크로폰 어레이 시스템을 제안한다. 제안한 시스템은 Generalized Sidelobe Canceller (GSC) 를 기반으로 하며, 새로운 적응 모드 제어기 (adaptation mode controller) 를 이용함을 특징으로 한다. 제안한 마이크로폰 어레이 시스템의 성능 평가를 위해, 일반 가정의 거실을 모델링한 실험 환경을 구축하여 실험을 수행하였다. 실험을 통해 제안된 시스템이 안정적으로 GSC의 적응 모드를 제어하고, 목적 신호의 왜곡을 최소화하면서도 간섭 신호 제거 성능이 뛰어남을 확인하였다.

• 한국자기공명학회논문지
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• 제15권2호
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• pp.157-174
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• 2011

Although the use of apodization functions in connection with postprocessing of a 2D NMR spectrum proves improved spectral quality, there is usually a trade-off between resolution enhancement and noise suppression due to a classical "uncertainty principle." In this study, therefore, a mathematical deconvolution technique called "Maximum Likelihood Deconvolution (MLD)" was adopted to achieve the spectral resolution and sensitivity enhancement simultaneously. The MLD technique greatly facilitates visualization and restoration of the genuine spectral information from complex 2D NMR spectra that would be problematic with the conventional apodization/FT processing. In particular, application of the MLD to the 2D-NOE spectrum would be very useful to derive the important proton connectivities, which are essential to achieve elucidating the 3D molecular structure.

• 한국멀티미디어학회논문지
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• 제21권8호
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• pp.821-828
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• 2018

Image Enhancement is used in various applications. Among them, unsharp masking methods can improve the contrast with a simple operation. However, it has problems of noise enhancement and halo effect caused by the use of a single filter. To solve this problems, adaptive processing using multi-scale and bilinear filters is being studied. These methods are effective for improving the halo effect, but it require a lot of calculation time. In this paper, we want to simplify adaptive filtering by generating a weight map based on local brightness. This weight map enables adaptive processing that eliminates the halo effect through a single multiplication operation. Through experiments, we confirmed the suppression of the halo effect through the result image of the proposed algorithm and existing algorithm.