• Journal of Information Processing Systems
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• 제6권1호
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• pp.53-66
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• 2010

The energy efficiency is a key design issue to improve the lifetime of the underwater sensor networks (UWSN) consisting of sensor nodes equipped with a small battery of limited energy resource. In this paper, we apply a hexagon tessellation with an ideal cell size to deploy the underwater sensor nodes for two-dimensional UWSN. Upon this setting, we propose an enhanced hybrid transmission method that forwards data packets in a mixed transmission way based on location dependent direct transmitting or uniform multi-hop forwarding. In order to select direct transmitting or uniform multi-hop forwarding, the proposed method applies the threshold annulus that is defined as the distance between the cluster head node and the base station (BS). Our simulation results show that the proposed method enhances the energy efficiency compared with the existing multi-hop forwarding methods and hybrid transmission methods

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 추계학술대회 논문요약집
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• pp.175-175
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• 2003

• 전기전자학회논문지
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• 제17권3호
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• pp.301-308
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• 2013

본 논문에서는 다중센서 기반의 하이브리드 조명제어 시스템을 제안한다. 제안된 하이브리드 조명제어 시스템은 가로등의 관리 및 제어를 위한 데이터 표시부와 데이터 변환 및 처리부, 게이트웨이의 통신부로 구성하여 설계한다. 데이터는 실시간으로 저장이 가능하도록 DB를 설계하고, 실시간으로 무선 원격제어 및 스케줄을 설정하여 모니터링 할 수 있도록 구현한다. 제안된 하이브리드 조명제어 시스템의 효율성 검증결과, 스마트 기기 및 포터블 PC 등과 연동하여 실시간 모니터링 및 원격 조명제어가 가능하였고, 결과적으로 에너지 절감 및 전기료 감소, 통신비용 감소 효과를 얻을 수 있었다.

• International Journal of Precision Engineering and Manufacturing
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• 제4권1호
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• pp.37-42
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• 2003

Active control of flexural vibrations of smart laminated composite beams has been carried out using piezoceramic sensor/actuator and viscoelastic material. The beams with passive constrained layer damping have been analyzed by formulating the equations of motion through the use of extended Hamilton's principle. The dynamic characteristics such as damping ratio and modal damping of the beam are calculated for various fiber orientations by means of iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations to design structure with maximum possible damping capacity.

• 대한임베디드공학회논문지
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• 제9권4호
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• pp.193-203
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• 2014

This paper implements a weather monitoring system based on wireless sensor network. The wireless sensor network protocol proposed in this paper adopts a TDMA styled MAC. The protocol is designed to balance the energy consumption among sensor nodes. Other purposes of the protocol are to avoid the hidden terminal problem in 2-hop star topology, and to allow a CSMA styled communication in a given time slot to support emergent messages. Also, this paper develops the hardware of sensor node, gateway and electric generator based on solar and windy energy. The test results on the implemented system show that the time slot of each node is shifted in circular manner to balance the waiting time for transmission, and the reliability of wireless communication is over 99%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.583-584
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• 2005

In this work, a novel hybrid FL sensor consisting of two Rogowski coils has been designed for the installation on the ground wire of the transmission tower. The operation range of these coils is as follows: 30kA for the fault current comingfrom the ground fault or short-circuit and for the lightning current up to 150kA over 500kHz. Thus, two important functions could be provided: one is to detect the fault current and the other one is to find the fault location between towers or the location of induced lightning stroke. The on-site investigation at 800kV test yard has been under progress for its on-site application.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 가을 학술발표논문집 Vol.33 No.2 (D)
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• pp.791-795
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• 2006

하이브리드 센서 네트워크에서 static sensor node들이 초기 배치된 후, coverage-hole을 결정하여, hole을 커버할 mobile sensor node들의 필요한 수 및 위치를 결정하고 배치하는 연구는 상당한 수준에 이르렀다. 그러나 mobile sensor node들을 호출하고 배치하는데 너무 많은 에너지를 소모하고 있다. 본 논문에서는 coverage-hole에서 mobile sensor node들을 호출하기 전에 mobile sensor node들을 최대한 coverage-hole에 가깝게 배치하여, 호출하는데 소요되는 에너지를 획기적으로 절감하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.152-152
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• 2000

In this paper, we propose a new approach to intelligent motion and autonomous maneuvering of mobile robots using hybrid system. In high Level, the discrete states are defined by using the sensor-based search windows and the reference motions of a mobile robot as a low vevel are specified in the abstracted motions, The mobile robots can perform both the motion planning and autonomous maneuvering with obstacle avoidance in indoor navigation problem. Simulation and experimental results show that hybrid system approach is an effective method for the autonomous maneuvering in indoor environments.

• 한국정보통신학회논문지
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• 제20권9호
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• pp.1747-1754
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• 2016

본 논문에서는 고정밀 하이브리드 온 칩 온도센서를 제안하였다. 제안된 온도센서에서는 SAR 타입 온도센서와 ${\Sigma}{\Delta}$타입 온도센서를 혼합하였다. SAR 타입 온도센서는 ${\Sigma}{\Delta}$타입 온도센서 보다 온도를 찾아가는 속도가 빠르지만 오차가 발생할 확률이 높은 단점이 있고, ${\Sigma}{\Delta}$ 타입 온도센서는 SAR 타입 온도센서 보다 정확하지만 속도가 느린 단점이 있다. 제안된 온도 센서는 두개의 온도 측정방법을 혼합하여 고정밀 고속 온도측정이 가능하다. 또한, 칩 제작 후 온도 오차 값을 메모리회로에 저장하여 온도 오차를 보상하는 회로를 포함하여 온도센서를 구현하였다. 제안된 온도센서는 $0.35{\mu}m$ CMOS 공정으로 제작되었다. 온도 정확도, 소비 전력, 칩 면적은 각각 $0.15^{\circ}C$, $540{\mu}W$, $1.2mm^2$였다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.149-156
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• 2003

This paper presents an underwater hybrid navigation system for a semi-autonomous underwater vehicle (SAUV). The navigation system consists of an inertial measurement unit (IMU), an ultra-short baseline (USBL) acoustic navigation sensor and a doppler velocity log (DVL) accompanying a magnetic compass. The errors of inertial measurement units increase with time due to the bias errors of gyros and accelerometers. A navigational system model is derived to include the error model of the USBL acoustic navigation sensor and the scale effect and bias errors of the DVL, of which the state equation composed of the navigation states and sensor parameters is 25 in the order. The conventional extended Kalman filter was used to propagate the error covariance, update the measurement errors and correct the state equation when the measurements are available. Simulation was performed with the 6-d.o.f. equations of motion of SAUV in a lawn-mowing survey mode. The hybrid underwater navigation system shows good tracking performance by updating the error covariance and correcting the system's states with the measurement errors from a DVL, a magnetic compass and a depth senor. The error of the estimated position still slowly drifts in horizontal plane about 3.5m for 500 seconds, which could be eliminated with the help of additional USBL information.