• 한국항행학회논문지
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• 제28권1호
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• pp.60-67
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• 2024

민간항공사고의 대부분은 인적요인에 의해 발생하고 특히 회전익 항공기는 예상하지 못하거나 의도하지 않게 악기상으로 진입하는 IIMC (instrument meteorological conditions) 상황에서의 사고가 많이 발생하고 있다. 이 연구는 저시정 조건에서 회전익 항공기 조종사의 에러율를 다각적으로 분석하여 비행특성에 관한 통찰력을 얻고 IIMC 상황에서의 사고를 줄이기 위한 방안을 연구하였다. 저시정 조건에서 조종사의 에러 발생율을 모션이 장착된 비행 시뮬레이터를 활용하였으며 65명의 조종사가 실험에 참여하였다. 실험을 통해 획득한 비행 데이터로 비행시정 감소, 공간정위상실 유무, 조종사 자격 등 다양한 조건에 따라 에러 발생율을 비교 분석하였다. 분석결과 다양한 조건에서 비행특성에 대한 특이점을 발견할 수 있었고 조종사의 자격 등급, 계기비행 (IFR; instrument flight rules) 자격 유무, 비행단계별 에러 발생율에 유의미한 차이가 발생하였다. 이와 같은 연구의 결과는 조종사의 교육 및 훈련프로그램을 개선하고 IIMC 상황에서 항공기 사고예방에 중요한 기여를 할 것으로 기대된다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권3호
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• pp.626-637
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• 2014

On ship, especially on large ship, the flexure deformation between Master (M)/Slave (S) Inertial Navigation System (INS) is a key factor which determines the accuracy of the integrated system of M/S INS. In engineering this flexure deformation will be increased with the added ship size. In the M/S INS integrated system, the attitude error between MINS and SINS cannot really reflect the misalignment angle change of SINS due to the flexure deformation. At the same time, the flexure deformation will bring the change of the lever arm size, which further induces the uncertainty of lever arm velocity, resulting in the velocity matching error. To solve this problem, a $H_{\infty}$ algorithm is proposed, in which the attitude and velocity matching error caused by deformation is considered as measurement noise with limited energy, and measurement noise will be restrained by the robustness of $H_{\infty}$ filter. Based on the classical "attitude plus velocity" matching method, the progress of M/S INS information fusion is simulated and compared by using three kinds of schemes, which are known and unknown flexure deformation with standard Kalman filter, and unknown flexure deformation with $H_{\infty}$ filter, respectively. Simulation results indicate that $H_{\infty}$ filter can effectively improve the accuracy of information fusion when flexure deformation is unknown but non-ignorable.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.972-978
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• 1989

Proposed is improved compact self-mixing type semiconductor-laser range finder, which measures mode-hop time interval (MHI). Measurement error caused by the fluctuation of MHI is greatly reduced by averaging many contiguous MHI's. The main cause of measurement error 1.5% at ranges from 0.1m to 0.8m is attributed to the optical phase change of a returned light from a focusing lens. Accuracy improvement by stabilization of the returned light is suggested.

• 산업융합연구
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• 제6권2호
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• pp.43-56
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• 2008

Measurement is used for evaluation of product or process exactly. If it couldn't measured correctly, Quality-cost must be raised and it would be hard to improve product quality. So, this study suggests improvement guide line for the multilateral problems of measuring instrument operation based on the investigation of 157 small and medium-sized enterprises in February, 2008. To use measuring instrument correctly, man who treat it must be accustomed with the structure, the performance, the method. The instrument is selected properly for the measurement goal. If not, results couldn't be correctly or wasted time, efforts, and costs. When selecting a instrument, the tolerance, the size, the figure, the material, and the efficiency must be considered. If the measuring instruments are controlled efficiently, it could be accomplished that improving product quality and coinciding with the goal of QM.

• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1342-1347
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• 2016

• 산업경영시스템학회지
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• 제23권61호
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• pp.89-98
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• 2000

For statistical process control, the process data are collected by the measurement system. But, the measurement system may have instrument error or/and operator error. In the measured values of products, the total observed variance consists of process variance and variance due to error of measurement system. In this paper, we design more practical T-s control chart considering estimated measurement error The effects of measurement error on the expected total cost and design parameters are investigated.

• 한국음향학회지
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• 제22권8호
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• pp.680-686
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• 2003

디지털 도파관 모델은 악기의 물리적 모델링에 사용되는 일반적인 방법이다. 디지털 도파관 모델에서 파동의 움직임은 시간 또는 공간을 기준으로 해석 가능하다. 음의 샘플링이 시간을 기준으로 이루어지므로 악기 모델은 시간에 의한 파동의 움직임으로 묘사되는 것이 일반적이다. 본 논문에서는 현에 대한 공간 기준의 디지털 도파관 모델에 악기 몸체 모델을 추가해 악기 음을 합성하였다. 그렇게 함으로써 합성 음의 음질을 향상시키고 악기 모델의 음색 조절 변수들을 효과적으로 처리할 수 있었다. 공간 기준 샘플링에서 현 및 몸체에서 발생하는 미소 지연 오차에 대해 설명하고 FD (Fractional Delay) 필터를 이용해 미소 지연을 처리하는 방법을 보였다. 그리고 지연에 수에 따른 합성음의 변화를 설명하고 그 결과를 시간 기준 디지털 도파관 모델과 비교하였다.

• 제어로봇시스템학회논문지
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• 제22권8호
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• pp.579-584
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• 2016

When surgical instruments are tracked in an image-guided surgical navigation system, a stereo vision system with high accuracy is generally used, which is called optical tracker. However, this optical tracker has the disadvantage that a line-of-sight between the tracker and surgical instrument must be maintained. Therefore, to complement the disadvantage of optical tracking systems, an internal vision sensor is attached to a surgical instrument in this paper. Monitoring the target marker pattern attached on patient with this vision sensor, this surgical instrument is possible to be tracked even when the line-of-sight of the optical tracker is occluded. To verify the system's effectiveness, a series of basic experiments is carried out. Lastly, an integration experiment is conducted. The experimental results show that rotational error is bounded to max $1.32^{\circ}$ and mean $0.35^{\circ}$, and translation error is in max 1.72mm and mean 0.58mm. Finally, it is confirmed that the proposed tool tracking method using an internal vision sensor is useful and effective to overcome the occlusion problem of the optical tracker.

• 대한안전경영과학회지
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• 제10권1호
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• pp.183-190
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• 2008

Measurement is a essential part in all kinds of industry, especially in manufacturing. But until now, measurement hasn't been located to the core of manufacturing in domestic. This study suggests improvement guide line for the multilateral problems of measuring instrument operation based on the investigation of small and medium-sized enterprises. To use measuring instrument correctly, man who treat it must be accustomed with the structure, the performance, the method. The measuring instrument must be corrected periodically. The correcting-schedule is established with environments with considering accuracy, stability, purpose, condition, and frequency.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.250-255
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• 1993

In this paper, for detection and isolation of instrument and process faults related with steam generator(S/G) in nuclear power plant, two types of observers are designed based on the linearized dynamic model of S/G : a bank of Dedicated Observers (DOS) for instrument faults detection and a bank of Unknown Input Observers(UIO) for process faults detection. And then, they are combined to decide which one between the above two faults occurs. In principle, the failure in ith instrument(process) can be isolated by monitoring the error between the ith output and its estimation obtained from the ith DOS(UIO). It is shown via computer simulations that the present scheme is feasible in finding out the source of a fault.