• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.505-507
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• 1995

Applications of the fiber optic sensing are glowing rapidly, particularly in situations where size, weight, speed, and immunity to electromagnetic interference are important considerations. The fiber optic current sensors have been developed for low frequency(60Hz) metering in electric power systems. But we try measure to high frequency large current by fiber optic current sensor based on Bi substituted rare earth iron garnet. In this paper, we report the linearity to 500 amperes and frequency response of signal processor and a result of detection the standard impulse large current of fiber optic impulse sensor system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.342-342
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• 2000

We present 3-axis stabilized spacecraft attitude determination algorithm using the magnetometer. The magnetometer has been used as a reliable, light-weight and inexpensive sensor in attitude determination and reaction wheel momentum dumping system. Recent studies have attempted to use the magnetometer when other attitude sensor, such as star tracker, fails. The differences between the measured and computed the Earth's magnetic field components are spacecraft attitude errors. In this paper, we propose extended Kalman filter(EKF) to determine spacecraft attitude with the magnetometer data and gyro-measured body rates. We develop and simulate this algorithm using MATLAB/SIMULINK. This algorithm can be used as a backup attitude determination system.

• International Journal of Aeronautical and Space Sciences
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• 제7권1호
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• pp.73-83
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• 2006

In this paper, a redundancy management system for aircraft is studied, and fault detection and isolation algorithms of inertial sensor system are proposed. Contrary to the conventional aircraft systems, UAV system cannot allow triple or quadruple hardware redundancy due to the limitations on space and weight. In the UAV system with dual sensors, it is very difficult to identify the faulty sensor. Also, conventional fault detection and isolation (FDI) method cannot isolate multiple faults in a triple redundancy system. In this paper, two FDI techniques are proposed. First, hardware based FDI technique is proposed, which combines a parity equation approach with a wavelet based technique. Second, analytic FDI technique based on the Kalman filter is proposed, which is a model-based FDI method utilizing the threshold value and the confirmation time. To provide the reference value for detecting the fault, residuals are calculated using the extended Kalman filter. To verify the effectiveness of the proposed FDI methods, numerical simulations are performed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권5호
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• pp.1733-1751
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• 2015

The IEEE 802.15.4 standard not only provides a maximum of seven guaranteed time slots (GTSs) for allocation within a superframe to support time-critical traffic, but also achieves ultralow complexity, cost, and power in low-rate and short-distance wireless personal area networks (WPANs). Real-time wireless body area sensor networks (WBASNs), as a special purpose WPAN, can perfectly use the IEEE 802. 15. 4 standard for its wireless connection. In this paper, we propose an adaptive GTS allocation scheme for real-time WBASN data transmissions with different priorities in consideration of low latency, fairness, and bandwidth utilization. The proposed GTS allocation scheme combines a weight-based priority assignment algorithm with an innovative starvation avoidance scheme. Simulation results show that the proposed method significantly outperforms the existing GTS implementation for the traditional IEEE 802.15.4 in terms of average delay, contention free period bandwidth utilization, and fairness.

• ETRI Journal
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• 제41권6호
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• pp.739-749
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• 2019

Security and accuracy are two issues in the localization of wireless sensor networks (WSNs) that are difficult to balance in hostile indoor environments. Massive numbers of malicious positioning requests may cause the functional failure of an entire WSN. To eliminate the misjudgments caused by malicious nodes, we propose a compressive-sensing-based multiregional secure localization (CSMR_SL) algorithm to reduce the impact of malicious users on secure positioning by considering the resource-constrained nature of WSNs. In CSMR_SL, a multiregion offline mechanism is introduced to identify malicious nodes and a preprocessing procedure is adopted to weight and balance the contributions of anchor nodes. Simulation results show that CSMR_SL may significantly improve robustness against attacks and reduce the influence of indoor environments while maintaining sufficient accuracy levels.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 한국컴퓨터종합학술대회 논문집 Vol.32 No.1 (A)
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• pp.427-429
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• 2005

Energy efficiency is the most challenging issue in wireless sensor network to prolong the life time of the network, as the sensors has to be unattended. Cluster based communication can reduce the traffic on the network and gives the opportunity to other sensors for periodic sleep and thus save energy. Passive clustering (PC) can perform a significant role to minimize the network load as it is less computational and light weight. First declaration wins method of PC without any priority generates severe collision in the network and forms the clusters very dense with large amount of overlapping region. We have proposed several modifications for the existing passive clustering algorithm to prolong the life time of the network with better cluster formation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.53.5-53
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• 2001

In continuous galvanizing process at steel making plant, coating weight on the surface of strip that pass through air knife is controlled by the pressure at the chamber of air knife and the gap between the nozzle of air knife and strip. The pressure can be easily measured and controlled. But it is difficult to measure the distance between Air knife nozzle and strip, and also difficult to decide how much distance air knife move. Because, the gap between nozzle and strip varies with the height of air knife, intermesh of stabilizing roll and welding of strips that have different thickness. In this research, we developed a gap sensor that can measure the relative distance between Air knife nozzle and strip. And several tests are performed to find optimal condition for application at real plant. We performed test in which the possibility of the sensor to apply ...

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.257-259
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• 2009

본 논문에서는 분산된 Sensor Module에서 실시간 계측된 데이터를 네트워크 시스템으로 구성하였다. 각각의 Sensor Module 사이의 실시간 통신이 필수적이며 정해진 시간 내에 모니터링을 위한 기기들의 데이터와 제어 명령이 전달되어야 안정성을 가질 수 있다. 본 연구에서는 산업 현장의 분산 제어에 사용되는 네트워크 중에 CAN(Controller Area Network) 통신을 사용하였다. CAN은 초기에 자동차 산업 분야에 적용하기 위해 고안된 시리얼 네트워크 통신 방식으로 근래에는 산업 전 분야에 폭 넓게 적용되고 있다. CAN controller는 SJA1000(PHILLIPS사(社)), CAN transceiver는 PCA82C250 (PHILLIPS사(社))으로 설계하였다.

• 센서학회지
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• 제28권1호
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• pp.7-12
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• 2019

Significant progress has been made recently in detection of highly sensitive volatile organic compounds (VOCs) using chemical sensors. Combined with the progress in design of micro sensors array and electronic nose systems, these advances enable new applications for detection of extremely low concentrations of breath-related VOCs. State of the art detection technology in turn enables commercial sensor systems for health care applications, with high detection sensitivity and small size, weight and power consumption characteristics. We have been developing an intelligent electronic nose system for detection of VOCs for healthcare breath analysis applications. This paper reviews our contribution to monitoring of respiratory diseases and to diabetic monitoring using an intelligent electronic nose system for detection of low concentration VOCs using breath analysis techniques.

• 전기전자학회논문지
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• 제23권4호
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• pp.1457-1460
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• 2019

본 논문에서는 위치추적과 방사선 측정이 가능한 일체형 방사선 피폭 방호 소방관 인명구조 경보기의 혼합형 센서부 개발을 제안한다. 방사선피폭선량을 측정하기 위하여 크기와 무게를 최소화 할 수 있는 반도체형 방사선 측정 센서인 PIN-Diode 방사선 측정 센서모듈을 사용한다. PIN-Diode 방식의 방사선 측정 센서 특성을 높이기 위하여 누설전류를 제거하기 위한 설계를 수행한다. IMU 센서모듈을 사용하여 3축에 대한 데이터와 가속도에 대한 수치를 합산하여 사고추정과 동시에 현재 소방관의 위치를 추정한다. 제안된 일체형 방사선 피폭 방호 소방관 인명구조 경보기를 위한 혼합형 센서부의 효율을 판단하기 위하여 공인시험기관에서 실험하였다. 누적선량 측정범위는 세계 최고 수준인 10μSv~10mSv 범위에서 측정이 되었다. 정확도는 ±6.3%~±9.0%(137Cs) 측정 불확도가 측정되어 국제 표준인 ±15% 이하에서 정상동작 됨이 확인되었다. 또한 위치정확성은 ±10% 이내로 측정되어 높은 수준의 결과가 도출되어 그 효용성이 입증되었다. 따라서 보다 많은 소방관에게 성능이 우수한 일체형 방사선 피폭 방호 소방관 인명구조 경보기 보급이 될 수 있으리라 기대된다.