• Journal of Platform Technology
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• 제12권2호
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• pp.34-44
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• 2024

본 논문은 모바일 장치에 장착된 충전식 배터리의 사용 시간을 연장하기 위하여 모바일 장치에서 전력 소모 비율을 가장 많이 차지하는 센싱 시스템의 전력 소모를 최소화하는 동적 클럭 공급 제어 알고리즘과 시스템 부하 전력 안정화 알고리즘을 제안하였다. 동적 클럭 공급 제어알고리즘은 센싱 시스템의 전력을 차단할 수 있도록 회로를 구성하여 센싱하지 않는 시간에는 전력을 차단하고 센서 변화율이 낮은 상태를 인지하여 측정 주기를 조정하는 방법으로 센싱 시스템에 소모되는 전력을 감소시킬 수 있다. 시스템 부하 전력 안정화 알고리즘은 전력 소모 상태에 따라 주변 모듈의 전력을 제어하는 알고리즘으로 많은 전력을 요구하는 상황일 경우 클럭 공급을 제어하여 동작 안정화 작업을 수행한다. 실험 결과, 동적 클럭 공급 제어 알고리즘만을 적용하는 경우 센싱 시스템에서 소모되는 전력을 17% 감소시키는 효과를 확인하였고, 시스템 부하 전력 안정화 알고리즘만을 적용하는 경우 9.3%의 전력 소모를 감소시켜 영상 처리와 같은 많은 전력을 요구하는 상황에서 안정적으로 동작할 수 있었다. 두 가지 알고리즘을 모두 적용하는 경우 배터리의 전력 소모가 알고리즘을 적용하기 전보다 67% 감소하였다. 이를 통해 제안한 방법의 신뢰성을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1540-1551
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• 2015

The detection of position and speed in BLDC motors without using position sensors has meant many efforts for the last decades. The aim of this paper is to develop a sensorless technique for detecting the position and speed of BLDC motors, and to overcome the drawbacks of position sensor-based methods by improving the performance of traditional approaches oriented to motor phase voltage sensing. The position and speed information is obtained by computing the derivative of the terminal phase voltages regarding to a virtual neutral point. For starting-up the motor and implementing the algorithms of the detection technique, a FPGA board with a real-time processor is used. Also, a versatile hardware has been developed for driving BLDC motors through pulse width modulation (PWM) signals. Delta and wye winding motors have been considered for evaluating the performance of the designed hardware and software, and tests with and without load are performed. Experimental results for validating the detection technique were attained in the range 5-1500 rpm and 5-150 rpm under no-load and full-load conditions, respectively. Specifically, speed and position square errors lower than 3 rpm and between 10º-30º were obtained without load. In addition, the speed and position errors after full-load tests were around 1 rpm and between 10º-15º, respectively. These results provide the evidence that the developed technique allows to detect the position and speed of BLDC motors with low accuracy errors at starting-up and over a wide speed range, and reduce the influence of noise in position sensing, which suggest that it can be satisfactorily used as a reliable alternative to position sensors in precision applications.

• 한국통신학회논문지
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• 제22권11호
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• pp.2563-2571
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• 1997

본 논문에서는 Slotted 대역 확산 ALOHA 네트워크의 효율을 향상시키기 위해 채널 제거 기법 CLSP (CLSP/ CC; Channel Load Sensing Protocol/Channel Clearance)를 제안하였다. 제안된 CLSP/CC는 이동국과 Hub에 간단한 채널 제거 가능만을 추가함으로써 오류가 발생된 패킷의 계속적인 전송을 억제하여, 불필요한 채널 사용을 줄이는 것을 가능하게 한다. 본 논문에서는 기존 CLSP와의 성능 비교를 위해 시뮬레이션을 이용하였으며, 성능 평가 요소로서 네트워크 효율, 평균 처리 시간, 재전송 상태의 이동국 수 등을 고려하였다. 시뮬레이션 결과에 따르면, 제안한 CLSP/CC는 CLSP에 바해 특히 트래픽 부하(offered load)가 많은 환경에서 네트워크 효율과 평균 처리 시간의 성능 향상이 두드러지고, 채널을 효율적으로 사용함으로써 지원할 수 있는 최대 트래픽 부하량이 증가하여, Slotted 대역 확산 ALOHA 네트워크에서 더욱 많은 이동국을 수용할 수 있음을 확인할 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1934-1937
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• 2005

This paper proposes suitable gait generation for dynamic walking of biped robot with varying load in real time. Author proposes the relationship between ZMP(Zero Moment Point) and measurement from FSR(Force Sensing Register). Simplifying this relationship, it is possible to reduce the computational time and control the biped robot in real time. If the weight of the biped robot varies in order to move some object, then joint trajectories of the the biped robot must be changed. When some object is loaded on the biped robot in it's home position, FSRs can measure the variation of weight. Evaluating the relations between varying load and stable gait of the biped robot, it can walk adaptively. This relation enables the biped robot to walk properly with varying load. The simulation is also represented in this paper which shows proposed relationships.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.222-232
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• 1999

This paper describes the development of a precision 3-component load cell with plate beams which may be used for measuring forces Fx, Fy and moment Mz simultaneously in industry. We have derived equations to predict the bending strains on the surface of the beams under forces or moment. We have also determined the attachment location of strain gages of each sensor and fabricated 3-component load cell. To evaluate the rated strain and interference error of each sensor, we have carried out characteristic test of precision 3-component load cell. It reveals that the rated strain calculated from the derived equations are good agreement with the results from Finite Element Method analysis.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.597-600
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• 2005

The software streaming technology enables telematics software to be automatically updated through a wireless network. When the software starts running, software streaming system inspects its version and then, automatically download latest one. The software streaming system breaks the software into several pieces that are streamed to the user as needed. In this way, software streaming system can improves the telematics application load time while updating the software through wireless network. In our experiments, the application load time was reduced about 7 times compared to downloading whole software at best case.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.674-678
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• 2003

This research is develop the sensing and measurement technology for measure that wheel/rail interaction force to use laser. Investigated existent laser measurement system, and examined transformation by load that action to wheel for achieve research purpose. A proposed to laser measurement system composition plan to analyze existent method that measure wheel/rail interaction force.

• Journal of Communications and Networks
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• 제12권4호
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• pp.308-316
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• 2010

The problem of compressed sensing (CS) based multiple access is studied under the assumption of random data traffic. In many multiple access systems, i.e., wireless sensor networks (WSNs), data arrival is random due to the bursty data traffic for every transmitter. Following the recently developed CS methodology, the technique of compressing the transmitter identities into data transmissions is proposed, such that it is unnecessary for a transmitter to inform the base station its identity and its request to transmit. The proposed compressed multiple access scheme identifies transmitters and recovers data symbols jointly. Numerical simulations demonstrate that, compared with traditional multiple access approaches like carrier sense multiple access (CSMA), the proposed CS based scheme achieves better expectation and variance of packet delays when the traffic load is not too small.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권6호
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• pp.810-817
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• 2014

An on-chip current sensor with fast response time for the peak-current-mode buck regulator is proposed. The initial operating points of the peak current sensor are determined in advance by the valley current level, which is sensed by a valley current sensor. As a result, the proposed current sensor achieves a fast response time of less than 20 ns, and a sensing accuracy of over 90%. Applying the proposed current sensor, the peak-current-mode buck regulator for the mobile application is realized with an operating frequency of 2 MHz, an output voltage of 0.8 V, a maximum load current of 500 mA, and a peak efficiency of over 83%.

• 산업기술연구
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• 제32권A호
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• pp.29-33
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• 2012

We demonstrated the viability of fully microfabricating SWCNT(single-wall carbon nanotube) film strain sensors for force and weight sensing. Our spray-deposited SWCNT film strain sensors showed good linearity over a range from 0 to 400 microstrain, and much higher sensitivity compared to commercial metal foil-type gauges. The number of grids and the thickness of the SWCNT film were found to have a significant effect on the strain sensing properties of the SWCNT film gauges. A strain sensing methode for the CNT-based strain gauges was also investigated using a binocular type beam load cells. Preliminary results indicate that the microfabrication method shown here is promising for developing a commercial strain gauge using a spray-coated SWCNT thin film. In the near future, various studies will be performed to further enhance the properties of the spray-coated SWCNT film strain sensors.