• 전자통신동향분석
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• 제36권2호
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• pp.56-64
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• 2021

Many computer vision algorithms are computationally expensive and require a lot of computing resources. Recently, owing to machine learning technology and high-performance embedded systems, vision processing applications, such as object detection, face recognition, and visual inspection, are widely used. However, on-devices need to use their resources to handle powerful vision works with low power consumption in heterogeneous environments. Consequently, global manufacturers are trying to lock many developers into their ecosystem, providing integrated low-power chips and dedicated vision libraries. Khronos Group-an international standard organization-has released the OpenVX standard for high-performance/low-power vision processing in heterogeneous on-device systems. This paper describes vision libraries for the embedded systems and presents the OpenVX standard along with related trends for on-device vision system.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.91-94
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• 2004

Ubiquitous sensor network is to manage and collect information autonomously by communicating user around device. Security requirements in Ubiquitous based on sensor network are as follows: a location of sensor, a restriction of performance by low electric power, communication by broadcasting, etc. We propose new mutual authentication protocol using a low power of sensor node. This protocol solved a low power problem by reducing calculation overload of sensor node using two steps, RM(Register Manager) and AM(Authentication Manager). Many operations performing the sensor node itself have a big overload in low power node. Our protocol reduces the operation number from sensor node. Also it is mutual authentication protocol in Ubiquitous network, which satisfies mutual authentication, session key establishment, user and device authentication, MITM attack, confidentiality, integrity, and is safe the security enemy with solving low electric power problem.

• 조명전기설비학회논문지
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• 제29권3호
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• pp.81-87
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• 2015

In order to effectively protect electrical and electronic circuits which are extremely susceptible to lightning surges, multi-stage surge protection circuits are required. This paper presents the operational characteristics of the two-stage hybrid surge protection circuit in extra-low voltage DC power lines. The hybrid surge protective device consists of the gas discharge tube, transient voltage suppressor, and series inductor. The response characteristics of the proposed hybrid surge protective device to combination waves were investigated. As a result, the proposed two-stage surge protective device to combination wave provides the tight clamping level of less than 50V. The firing of the gas discharge tube to lightning surges depends on the de-coupling inductance and the rate-of-change of the current flowing through the transient voltage suppressor. The coordination between the upstream and downstream components of the hybrid surge protective device was satisfactorily achieved. The inductance of a de-coupler in surge protective circuits for low-voltage DC power lines, relative to a resistance, is sufficiently effective. The voltage drop and power loss due to the proposed surge protective device are ignored during normal operation of the systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.131-135
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• 2009

This paper reviews the characteristics of Power MOSFET device technology that are leading to improvements in power loss for power electronic system. The silicon bipolar power transistor has been displaced by silicon power MOSFET's in low and high voltage system. The power electronic technology requires the marriage of power device technology with MOS-gated device and bipolar analog circuits.

• 대한임베디드공학회논문지
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• 제10권2호
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• pp.91-99
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• 2015

The electric power consumed by the embedded devices has become a critical issue because the reduction of power consumption is an important factor to prolong the battery-operated devices' lifetime. Many researches and techniques to reduce the power consumption have been proposed and developed but any power method cannot guarantee optimal power consumption of an embedded device - it would be faced with numerous situation - in all ways. Specifically, power researches for embedded devices deployed in the industry field have hardly been done. In this paper, low power service is proposed to minimize power reduction with the several usage status of embedded devices in the industry field. The usage status is basically classified according to the distance between the device and the user which is obtained by the ultrasonic and PIR sensor. The performance evaluation shows that the proposed scheme can reduce the power consumption by up to 45.3% compared to the device with no power reduction scheme. It also shows that the power consumption of the proposed scheme is 5.2% ~ 16.8% lower than that of the timeout scheme.

• 한국정보통신학회논문지
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• 제18권2호
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• pp.466-474
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• 2014

무선 네트워크 기술과 모바일 프로세서의 성능이 향상됨에 따라 스마트 폰과 같은 무선통신이 가능한 소형 단말이 널리 활용되고 있다. 이러한 이동형 장치는 GPS를 이용하여 위치정보의 활용이 가능하여 위치정보를 기반으로 하는 서비스가 증가하고 있다. GPS는 위성신호를 수신할 수 없는 실내와 전파음영지역에서 위치 정보를 제공하지 못하며, 근거리 통신기술을 이용하는 시스템은 인프라의 구축이 필수적이다. IEEE 802.11을 기반으로 하는 추적 시스템은 널리 보급된 AP 인프라를 기반으로 위치 측정이 가능하나 표준 동작을 따를 때 심각한 전력소모의 문제가 있다. 본 논문에서는 IEEE 802.11 기반 저전력 위치 추적 장치를 제안한다. 저전력 동작을 위해 채널 검색 및 연결유지로 인한 전력소모를 최소화하여 동작시간을 극대화 하였다. 성능평가를 위해 저전력 태그 장치를 설계 및 구현하여 전력소모를 측정하였으며, 시뮬레이션 결과 기본 방법에 비해 제안 방법의 전력소모가 46% 감소함을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제16권2호
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• pp.193-199
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• 2011

본 논문에서는 이동기기에서 배터리를 고려한 저전력 알고리즘을 제안하였다. 제안한 알고리즘은 이동기기에서 배터리의 잔량에 따라 태스크를 수행할 수 있도록 소모전력을 줄이는 방법으로 주파수를 변화시킨다. 배터리의 잔량이 수행하고자하는 태스크의 소모 전력보다 작을 경우 태스크를 수행시키기 위해 주파수를 낮춘다. 주파수 조절은 태스크에 따라 전체 시스템에서 사용되는 디바이스들 중에서 가장 높은 주파수를 가진 디바이스를 우선대상으로 수행한다. 주파수의 감소는 두 번째로 큰 주파수를 가진 디바이스의 주파수로 변화하여 소모전력을 계산한다. 계산된 소모전력이 배터리의 잔량보다 클 경우 단계적으로 주파수를 조절하여 소모전력을 낮추며 배터리의 잔량으로 태스크를 수행 할 수 있을 때 까지 주파수를 조절한다. 실험은 주파수를 조절하여 소모 전력을 줄이는 방법을 이용한[6]과 같은 환경에서 배터리의 잔량을 고려하여 태스크를 수행할 수 있도록 주파수를 조절하였다. 실험 결과 [6]에서 수행되지 않는 배터리 잔량에서도 태스크가 동작되는 결과를 나타내었다.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1999년도 추계학술대회 논문집
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• pp.272-277
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• 1999

The necessity of voice recording device was increased using voice signal IC with designed LSI/VLSI. The control unit which developed here voice recorder has low power dissipation, portable, and comfortable using voice source. However, the Korea voice recorder abilities far behind of foreign products for its performance and size on sailing. So we used Chua circuit to improvement voice quality abilities after minimize power supply device and circuit by designing voice recording device into lower power dissipation power circuit.

• IEIE Transactions on Smart Processing and Computing
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• 제3권4호
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• pp.221-225
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• 2014

Low power RF devices, such as RFID and Zigbee, are important for ubiquitous sensing. These devices, however, are powered by portable energy sources, such as batteries, which limits their use. To mitigate this problem, this study developed RF energy harvesting with W-CDMA for a low power RF device. Diodes are required with a low turn on voltage because the diode threshold is larger than the received peak voltage of the rectifying antenna (rectenna). Therefore, a Schottky diode HSMS-286 was used. A prototype of RF energy harvesting device showed the maximum gain of 5.8dBi for the W-CDMA signal. The 16 patch antennas were manufactured with a 10 dielectric constant PTFT board. In low power RF devices, the transmitter requires a step-up voltage of 2.5~5V with up to 35 mA. To meet this requirement, the Texas Instruments TPS61220 was used as a low input voltage step-up converter. From the evaluated result, the achievable incident power of the rectenna at 926mV to operate Zigbee can be obtained within a distance of 12m.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.191-194
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• 1999

The balanced amplifier is a practical amplifier to, implement a broadband amplifier that has flat gain and good input and output VSWR. Three-stage amplifier design procedure usually divided into three partition satisfying the following requirements : low noise figure, high gain and high power output. FHX35LG HEMT device is used in the design can be obtained low noise figure at the first-stage, MGA82563 MMIC device is used in the design can be maintained high gain at the second-stage, and AHI MMIC device is used in the design can be required high power output at the third-stage. The results of three-stage balanced amplifier show that power gain is about 40㏈, noise figure is less than 1.2㏈ at operating frequency.