• 센서학회지
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• 제13권3호
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• pp.236-243
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• 2004

In this paper, we proposed a brain-computer interface system using EEG signals. It can generate 4 direction command signal from EEG signals captured during imagination of subjects. Bandpass filter used for preprocessing to detect the brain signal, and the power spectrum at a specific frequency domain of the EEG signals for concentration status and non-concentration one is used for feature. In order to generate an adequate signal for controlling the 4 direction movement, we propose a new interface system implemented by using a support vector machine and a time-multiplexing method. Moreover, bio-feed back process and on-line adaptive pattern recognition mechanism are also considered in the proposed system. Computer experimental results show that the proposed method is effective to recognize the non-stational brain wave signal.

• 전자공학회논문지S
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• 제35S권5호
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• pp.35-41
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• 1998

This paper presents a decoupling controller of the missile seeker scan loop with a spin-stabilized platform. A precise seeker motion with respect to the scan command is essential for the higher acquisition probability of the target. As the seeker scan loop is a deeply cross-coupled two input two output system, an accurate pointing or scanning for each axis to the target is very difficult, even though provided with the help of a high performance controller. When a decoupling control is applied to the seeker scan loop, the cross-coupling between two axes can be reduced to a remarkable amount. As a low order of controller is required for the real time operation, a PI controller with decoupling filter is suggested and compared with other controllers. A linearized dynamic model of seeker scan loop is used and validated through the comparison of experimental results of step responses.

• International Journal of Aeronautical and Space Sciences
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• 제13권1호
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• pp.74-89
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• 2012

An adaptive backstepping controller is designed for the automatic landing of a fixed-wing aircraft. The backstepping control scheme is adopted by using the nonlinear six degree-of-freedom dynamics of the aircraft during the landing phase. The adaptive law is integrated along with the backstepping controller in order to estimate the aircraft modeling errors as well as the external disturbance. The dynamic constraints of the states and the actuator inputs are taken into account in the parameter adaptation. This is done to prevent an aggressive adaptation and to provide reliable control commands. Numerical simulations were performed to verify the performance of the proposed control law for the landing of the aircraft with the presence of gust and actuator stuck.

• 한국군사과학기술학회지
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• 제16권6호
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• pp.752-761
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• 2013

A new gun fire control system has been developed for the Korean next generation frigate class. The engineering requirement was far more tightened than the PKG-A class for the firing range availability and gun control function since 5 inch gun is adopted for the new ship. We mention about the principal technologies required to build a generic gun fire control system and proposed methods for the new gun fire control system. The new system has been designed based on the proposed methods in order to satisfy the requirement and functionality has been proved to be acceptable through the sea trial by Korean navy.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 추계학술대회
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• pp.235-237
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• 2017

전투무선망을 통해 방공C2A 체계로부터 전송되는 표적거리는 전투무성망의 여러 가지 특성으로 인해 오차가 발생한다. 본 논문에서는 칼만필터를 이용한 거리추정 알고리즘의 성능을 향상 시켜 오차를 최소화할 수 있는 방법을 제안한다.

• 한국음향학회지
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• 제18권2호
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• pp.11-17
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• 1999

본 논문에서는 DHMM(Discrete Hidden Markov Model) 기반의 음성 인식 시스템에서 소음에 강인한 인식 성능을 얻기 위하여, 관찰 확률 스무딩(observation probability smoothing) 방법을 제안하고, 자동차 소음하에서의 음성 인식에 적합한 소음처리 기법을 실험을 통해 제시한다. 제안된 관찰 확률 스무딩 방법은 입력되는 음성의 특징벡터가 소음에 오염되어 양자화(vector quantization) 과정에서 적절한 코드워드(codeword)가 아닌 다른 코드워드로 양자화됨으로써 발생하는 인식성능 저하를 막기 위하여, 각각의 코드워드와 거리가 가까운 코드워드들의 관찰 확률값을 높여주는 방법이다. 이 밖에 자동차 소음에 대한 대처 방안으로 특징 벡터의 거리 측정시의 리프터(lifter) 사용, 고역 통과 필터(high pass filter) 사용, 스펙트럴 차감법(spectral subtraction) 사용 등의 성능을 평가한다. 인식 실험은 자동차 정지 중과 주행 중의 두 가지 상황에서 녹음된 한국어 단독 숫자음과 명령어 14단어에 대해 수행하였으며, 정지 중 97.4%와 주행 중 59.1%의 인식률로부터, 제안된 관찰 확률 스무딩 방법과 리프터, 고역 통과 필터, 스팩트럴 차감법의 소음 처리 기법을 추가한 결과, 정지 중 98.3%와 주행 중 88.6%의 인식률을 얻을 수 있었다.

• 한국지능시스템학회논문지
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• 제27권2호
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• pp.126-131
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• 2017

본 논문에서는 손짓을 이용하여 로봇에게 명령을 내릴 때, 사용자의 여러 가지 손짓 중 의미 있는 동작을 추출하기 위한 방법을 제시한다. 로봇에게 명령을 내릴 때, 사람들의 손짓은 준비동작, 본 동작, 마무리 동작으로 구분할 수 있다. 여기에서 본 동작이 로봇에게 명령을 전달하는 의미 있는 동작이고 다른 동작은 그 동작을 위한 의미 없는 보조 동작이다. 따라서 연속적인 손짓에서 본 동작만을 추출해야 한다. 또한 사람들은 무위식적으로 손을 움직일 수 있는데 이러한 동작들 역시 의미가 없는 동작으로 로봇이 판단하여야 한다. 본 연구에서는 키넥트 센서를 이용하여 획득한 거리영상에서 사람의 골격자료를 획득하여 손을 추출하고, 칼만필터를 이용하여 손의 위치를 추적하면서 의미 있는 손동작과 의미 없는 손동작을 구분하고 은닉 마코프 모델을 이용하여 손짓을 인식한다.

• 천문학회보
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• 제44권2호
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• pp.57.4-57.4
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• 2019

BITSE is a project of balloon-borne experiments for a next-generation solar coronagraph developed by a collaboration with KASI and NASA. The coronagraph is built to observe the linearly polarized brightness of solar corona with a polarization camera, a filter wheel, and an aperture door. For the observation, the coronagraph is supported by the power distribution unit (PDU), a pointing system WASP (Wallops Arc-Second Pointer), telemetry & telecommand system SIP (Support Instrument Package) which are developed at NASA's Goddard Space Flight Center, Wallops Flight Facility, and Columbia Scientific Balloon Facility. The BITSE Command and Data Handling (C&DH) system used a cost-off-the-shelf electronics to process all data sent and received by the coronagraph, including the support system operation by RS232/422, USB3, Ethernet, and digital and analog signals. The flight software is developed using the core Flight System (cFS) which is a reusable software framework and set of reusable software applications which take advantage of a rich heritage of successful space mission of NASA. The flight software can process encoding and decoding data, control the subsystems, and provide observation autonomy. We developed a python-based testing framework to improve software reliability. The flight software development is one of the crucial contributions of KASI and an important milestone for the next project which is developing a solar coronagraph to be installed at International Space Station.

• 한국항행학회논문지
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• 제20권6호
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• pp.528-538
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• 2016

본 논문에서는 한국형 전술데이터링크 기반의 상대항법 운용을 위해 확장 칼만필터 기반의 상대항법 알고리즘을 적용한 항법 시스템을 제안하였다. 한국형 전술데이터링크는 한국군 합동작전 수행능력 향상을 위해 Link-16을 기반으로 설계된 전술데이터 링크로 작전수행 및 표적재원 등의 정보를 다루고 있다. 한국형 전술데이터링크의 통신 채널에서 위치정보를 포함하는 PPLI 메시지와 터미널로부터 산출 가능한 TOA 측정치를 활용하여 항법 백업 시스템으로 운용이 가능하다. 본 논문에서는 제안한 한국형 전술데이터링크 기반의 상대항법 시스템의운용 가능성 및 오차요소에 따른 성능분석을 수행하였으며, 이를 위해 소프트웨어 기반의 상대항법 시뮬레이션 플랫폼을 설계하여 다양한 환경에서 추정 성능을 분석하였다.

• Smart Structures and Systems
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• 제31권3호
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• pp.259-273
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• 2023

Real-time hybrid simulation (RTHS) is an effective experimental technique for structural dynamic assessment. However, time delay causes displacement de-synchronization at the interface between the numerical and physical substructures, negatively affecting the accuracy and stability of RTHS. To this end, the authors have proposed a model-based adaptive control strategy with a Kalman filter (MAC-KF). In the proposed method, the time delay is mainly mitigated by a parameterized feedforward controller, which is designed using the discrete inverse model of the control plant and adjusted using the KF based on the displacement command and measurement. A feedback controller is employed to improve the robustness of the controller. The objective of this study is to further validate the power of dealing with a nonlinear control plant and to investigate the potential challenges of the proposed method through actual experiments. In particular, the effect of the order of the feedforward controller on tracking performance was numerically investigated using a nonlinear control plant; a series of actual RTHS of a frame structure equipped with a magnetorheological damper was performed using the proposed method. The findings reveal significant improvement in tracking accuracy, demonstrating that the proposed method effectively suppresses the time delay in RTHS. In addition, the parameters of the control plant are timely updated, indicating that it is feasible to estimate the control plant parameter by KF. The order of the feedforward controller has a limited effect on the control performance of the MAC-KF method, and the feedback controller is beneficial to promote the accuracy of RTHS.