• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.43-44
• /
• 2006

The performance of the direct adaptive time-delay filter depends on the select time-delay. In this paper, the authors introduce a new scheme to adapt the time-delay which is to be used in conjunction with the direct adaptive command shaping for the improved vibration suppression in flexible motion system. In order to formulate the time-delay adaptation scheme, the authors have analyzed the effect of the time-delay value on the performance of the direct adaptive command shaping filter. By modifying the direct adaptation formula based on the analysis result the authors have established a set of equations to adapt the time-delay toward the optimal value. Simulation results show the effectiveness of the proposed time-delay adaptation approach for the improved vibration suppression.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2001.05a
• /
• pp.48-53
• /
• 2001

가상현실에 대한 인간의 감성인자를 고려한 재현용 시스템들은 컴퓨터 및 주변장치의 발달과 더불어 다각적인 방향으로 개발되었다. 가상현실의 환경을 조성하기 위해서는 인간의 감성인자들에 대한 연구가 필요하다. 본 연구는 이러한 가상현실 환경에서의 인간의 감성인자들 중 인체의 운동 감성인자를 연구하여, 가상현실의 운동 환경을 가장 효과적으로 재현할 수 있도록 하는 데 그 목적을 두고 있다. 즉 가상현실 환경에서의 운동감을 야기시키는 운동시스템 운동판의 최적의 운동을 발생시킬 운동명령을 생성하는 워시아웃 알고리즘(Washout Algorithm)의 물리적 특성을 연구하고, 워시아웃 알고리즘 내부의 고역필터들의 계수 의미를 파악하여 워시아웃 알고리즘에 의해 생성된 운동명령을 최선의 운동명령으로 보정키 위한 방법을 연구하고자 하였다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.10a
• /
• pp.562-564
• /
• 2004

캐시 선인출 기법은 메모리 참조에 따른 지연시간을 줄이는 효과적인 방법이다. 그러나 너무 적극적인 선인출은 캐시 오염을 유발시켜 선인출에 의한 장점을 상쇄시킨다. 본 연구에서는 캐시의 오염을 줄이기 위해 동적으로 필터 테이블을 참조하여 선인출 명령을 수행할 지의 여부를 결정하는 4가지 필터링 방법들을 비교 평가한다. 비교 연구를 위한 이상적인 필터링 구조를 제안하였으며, 기존 연구에서의 잠김 현상을 개선하기 위한 이진 상태 구조를 제안하였다. 또한, 정교한 필터링을 위한 블록주소 참조 방식을 제안하였다. 일반적으로 많이 사용되는 일반 벤치마크 프로그램과 멀티미디어 벤치마크 프로그램들에 대하여 실험한 결과, 캐시 미스율이 이진 상태 구조는 평균 5.6%, 블록주소 참조 구조는 7.9% 각각 감소하였다.

• Journal of the KSME
• /
• v.50 no.4
• /
• pp.36-41
• /
• 2010

이 글에서는 정밀유도포탄의 국내외 개발 현황과 특징에 대하여 분석하고, 정밀유도포탄을 개발하기 위해 소프트웨어 관점에서의 주요 설계 요소와 설계 방법에 대하여 기술하였다. 소프트웨어적으로 해결해야 되는 문제로 초기자세 예측과 바람 예측을 제기하였으며, 칼만필터를 활용하여 각 알고리즘을 설계하는 방안에 대하여 제시하고 있다. 뿐만 아니라 정밀한 결과를 위하여 GPS/INS 통합 알고리즘과 유도명령을 구성하는 방안에 대하여 기술하였다.

• Aerospace Engineering and Technology
• /
• v.1 no.2
• /
• pp.105-112
• /
• 2002

In this paper, a servo filter design for the gimbal engine actuator system of KSR-III(Korea Sounding Rocket-III) is considered. A reasonable filter structure is determined based on the actuator analytic models. The servo filter consists of a 2-nd order lowpass filter and a 1-st order compensator. The lowpass filter is required to protect the actuator from high frequency vibration, and the compensator to enhance the resulting stability. A Butterworth type servo filter is considered as the simplest one. The final servo filter type is determined by evaluating simultaneously both high frequency gain reduction performance and the corresponding KSR-III stability margin. Consequently it is revealed that a notch type servo filter located on the error between command signal and feedback signal in the control loop is very effective. Later, based on the proposed servo filter type, an onboard servo filter hardware of KSR-III will be designed and tested.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.23 no.2
• /
• pp.63-68
• /
• 2015

This paper presents the algorithm for envelope protection of helicopters. The algorithm consists of two feedback control loops: inner loop and outer loop. As an inner loop control, model following control is designed to meet the ADS-33 handling qualities specification by minimizing the tracking errors between the responses of the actual model and those of the command filter. In order to implement envelope protection, saturation limiter is imposed to command channels in command filter, whose limits are computed corresponding to the envelope limit. Fast model predictive control is designed as an outer loop control to deal with saturation constraints generated by the inner loop envelope protection and also imposed by outer loop envelope protection variables. Simulation results show that the proposed algorithm yields good envelope protection performance.

• Journal of the Society of Naval Architects of Korea
• /
• v.38 no.2
• /
• pp.33-43
• /
• 2001

The design and construction of special purpose vessels such as drillship and shuttle tankers have been increased. These vessels install the DPS(dynamic positioning systems) to maintain the position and heading for long-time operation. This paper deals with the experimental method for model-based DP system and the control theory and filter algorithms. In this experiment, the length of model ship is 4 meters and it has three thrusters to maintain the position. The ability of tracking along the given course and keeping of heading in waves are confirmed. For the calculation of thruster input the PID control theory are adopted and the effects of PID gain were investigated. To estimate the low frequency motions Kalman filter and digital filter were used and their effects were investigated.

• Journal of the Institute of Convergence Signal Processing
• /
• v.8 no.2
• /
• pp.130-135
• /
• 2007

This paper deals with a controller design for a 2 dimensional aeroelatic model which has unknown parameters including polynomial type nonlinearity. Actually in case of state and acuator signal having magnitude, rate and bandwidth limitations, the controller can't be implemented and so in each case, a filter is used for implementation. First, error signals are defined upon the backstepping theory, and tracking error signals are also defined due to command signal and filter signals and then compensated tracking error signals are defined. Lastly, a Lyapunov function is defined for the stabilization and from this method, an adaptive law is derived. Simulations are done for the demonstrtion of the effectiveness of the algorithms.

• Journal of Digital Contents Society
• /
• v.19 no.2
• /
• pp.327-334
• /
• 2018

When a PC is infected with a malicious code, it communicates with the control and command (C&C) server and, by the attacker's instructions, spreads to the internal network and acquires information. The company focuses on preventing attacks from the outside in advance, but malicious codes aiming at APT attacks are infiltrated into the inside somehow. In order to prevent the spread of the damage, it is necessary to perform internal monitoring to detect a PC that is infected with malicious code and attempts to communicate with the C&C server. In this paper, a destination IP monitoring method is proposed in this paper using Bloom filter to quickly and effectively check whether the destination IP of many packets is in the blacklist.

• Journal of Broadcast Engineering
• /
• v.9 no.1
• /
• pp.9-16
• /
• 2004

In this paper, we present a speech enhancement method as a pre-processor for voice commander under car environment. For the friendly and safe use of voice commander in a running car, non-stationary audio signals such as music and non-candidate speech should be reduced. Ow technique is a two microphone-based one. It consists of two parts Blind Source Separation (BSS) and Kalman filtering. Firstly, BSS is operated as a spatial filter to deal with non-stationary signals and then car noise is reduced by kalman filtering as a temporal filter. Algorithm Performance is tested for speech recognition. And the results show that our two microphone-based technique can be a good candidate to a voice commander.