• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.339-346
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• 2011

In the existing RF communication based WPAN environment, a lowering of battery span and interference problem among sensors occur because the value of output is set and transmitted steadily when the system on sensor is initialized. Therefore, this paper proposes a framework and a transmit method with low power which decreases the electricity consumption by properly controling transmit power of opponent by received signal strength indicator(RSSI) of each sensor. The system proposes a power-lowering method by controling transmit power properly by the transmit intensity of the connected sensor after being affected by the transmit intensity of surrounded sensor. The framework that is proposed in this paper includes data transmit module, transmit power manager module, transmit power searching module, signal transmit module, and signal receiving module.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2006.06a
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• pp.737-747
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• 2006

USN(Ubiquitous Sensor Network)는 환경 및 재난 관리, 에너지 관리, 의료 및 건강 서비스, 물류 및 유통관리 등의 다양한 분야에 응용될 수 있는 네트워크이다. USN은 저 전력으로 센싱 기능, 연산 및 네트워크 기능을 수행하는 초소형의 노드들이 한 지역에 분산되어 망을 구성하는데 USN의 노드들은 전력을 추가적으로 공급받지 못하므로 매우 제한된 전력을 이용하여 주어진 임무를 수행하여야 한다. 또한 노드의 고장으로 인해 토폴로지가 변경될 가능성이 크다. 이러한 특성 때문에 기존의 무선 ad hoc 네트워크를 위해 제안된 경로설정 기법들은 USN 환경에 적합하지 않다. 본 논문에서는 USN 노드의 전력 소비를 최소화함으로써 노드 생존시간을 최대화하기 위한 경로실정 기법을 제안하고 성능을 평가하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1A
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• pp.65-71
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• 2006

In IEEE 802.11b wireless network, the access point(AP) sends beacons periodically to manage stations when they are running in low power mode. Stations contend for the transmission medium after they receive a beacon and continuously check its state until it becomes available. Thus the energy consumption of each station increases as the load of wireless network. In this paper, we propose a method to reduce energy consumption controlling virtual bitmap in wireless network with multiple stations. The problems of low power mode in IEEE 802.11b wireless interface are described and a new method to reduce energy consumption is proposed. The proposed method is simulated with the network simulator, ns2, and compared with the low power mode of the IEEE 802.11b. The result measured in terms of station's wakeup time shows some enhancement in energy consumption when multiple stations are communicating through the AP in wireless network.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.9-14
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• 2017

Recently, the Internet of Things are developing in accordance with the technology of implementation in low-cost, small-size, low power consumption and smart sensor that can communicate using the internet. Especially, key management researches for secure information transmission based on the Internet of Things (IoT) are actively performing. But, Internet of Things(IoT) are uses sensor. Therefore low-power consumption and small-memory are restrictive condition. As a result, managing the key is difficult as a general security measure. However, The problem of secure key management is an essential challenge For the continuous development of the Internet of things. In this paper, we propose a key distribution and management technique in secure Internet of things. In the key generation and management stage, it satisfies the conditions and without physically constrained for IoT based communication.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.10
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• pp.95-104
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• 2004

This paper propose a motion estimator architecture to reduce the power consumption of the most-power-consuming motion estimation method when designing multimedia SoC with deep submicron technologies below 0.13${\mu}{\textrm}{m}$. The proposed architecture considers both dynamic and static power consumption so that it is suitable for large leakage process technologies, while conventional architectures consider only dynamic power consumption. Consequently, it is suitable for mobile information terminals such as mobile videophone where efficient power management is essential. It exploits full search method for simple hardware implementation. It also exploits early break-off method to reduce dynamic power consumption. To reduce static power consumption, megablock shutdown method considering power line noise is also employed. To evaluate the proposed architecture when applied multimedia SoC, system-level control flow and low-power control algorithm are developed and the power consumption was calculated based on thor From the simulation results, power consumption was reduced to about 60%. Considering the line width reduction and increased leakage current due to heat dissipation in chip core, the proposed architecture shows steady power reduction while it goes worse in conventional architectures.

• Journal of Energy Engineering
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• v.9 no.3
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• pp.163-169
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• 2000

전력품질에 대한 관심과 요구가 증가되고 있는 최근의 상황하에서 기존의 전력품질 관리방 법의 개선과 새롭게 대두되는 전력품질 사항에 대한 정확한 정의와 대책이 필요하게 되었 다. 국내에서는 아직 대비가 미비한 실정이며 외국의 경우에는 장비의 도입비용이 고가이며 고정형이 대부분인 문제가 있다. 본 논문에서는 새롭게 대두되는 미소 외란에 의한 전력품 질 사항에 대해 명확하게 판단하고 검출할 수 있는 알고리즘을 제시하였다. 개발된 측정장 치는 이동형으로 만들어졌으며 제작소요비용이 몇십 만원대로 그 기능이나 성능에 비해 저 렴하다. 그리고 500$\mu\textrm{s}$의 샘플링 시간에 의해 만들어진 입력 데이터로 실험을 하고 결과를 분석하여 장치의 효용성을 입증하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.233-234
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• 2017

본 논문에서는 섬유형 전극을 부착한 Chest Belt형 소형 저전력 단일 채널 ECG 시스템을 통한 심박 신호를 무선 전송하고 개인용 휴대 이동통신 단말기가 이를 수신하여 HRV(Heart rate variability)를 분석하고 이를 이용하여 정신적 스트레스 상태를 판단할 수 있는 스트레스 지수를 도출할 수 있는 시스템을 설계하고자 한다. 이를 위하여 저전력 MCU 설계를 통한 HR 모듈 및 검출 알고리즘을 개발하고 감정 상태를 분석할 수 있는 알고리즘을 제안한다. 본 연구의 결과는 일반인이나 만성절환자의 스트레스 상태를 감지하여 스트레스를 낮춰주는 음악 및 호흡 등을 통해 사용자의 스트레스를 감소 등의 건강관리에 활용될 수 있을 것으로 사료된다.

• Information and Communications Magazine
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• v.25 no.2
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• pp.18-25
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• 2008

지능형 센서, 마이크로전자공학 및 집적회로, SoC (system-on-chip) 설계와 저전력 무선통신의 급속한 발달로 소형 지능형 센서노드의 개발을 촉진하여 왔다. 이러한 센서 노드는 인체센서네트워크(Body Sensor Network;BSN)의 개발에 초석이 되며, 향후 이 분야의 급속한 발전을 기대하게 된다. 초 저전력 RF 기술의 발전은 침투식 및 비침투식 장치들이 원격 단말과 데이터 전송을가능케 하며, 환자를 장기간 모니터링하여 의료 전문가에게 실시간으로 피드백 함으로써 건강관리 시스템의 일대 혁신을 일으키고 있다. 본 기고에서는 이식형 의료 장치들간의 무선통신 방법과 BSN 분야에서의 최근 기술적 발전동향에 주안점을 두어, 인체 내장형 및 인체 부착형 통신 네트워크 구조를 파악한 후, 이들 분야에서 미해결 쟁점과 난제에 관하여 분석하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.5 s.335
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• pp.63-72
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• 2005

This paper describes a new approach for the operating system level power management to reduce the energy consumed in the IO devices in a robot platform, which provides various functions such as navigation, multimedia application, and wireless communication. The policy proposed in the paper, which was named the Energy-Aware Job Schedule (EAJS), rearranges the jobs scattered so that the idle periods of the devices are clustered into a time period and the devices are shut down during their idle period. The EAJS selects a schedule that consumes the minimum energyamong the schedules that satisfy the buffer and time constraints. Note that the burst job execution needs a larger memory buffer and causes a longer time delay from generating the job request until to finishing it. A prototype of the EAJS is implemented on the Linux kernel that manages the robot system. The experiment results show that a maximum $44\%$ power saving on a DSP and a wireless LAN card can be obtained with the EAJS.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.246-248
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• 2021

Recently data has been transformed into a data economy and society that acts as a catalyst for the development of all industries and the creation of new value, and COVID-19 is accelerating digital transformation. In the upcoming intelligent Internet of Things era, the availability of decentralized systems such as blockchain and mixnet is emerging to solve the security problems of centralized systems that makes it difficult to utilize data safely and efficiently. Blockchain manages data in a transparent and decentralized manner and guarantees the reliability and integrity of the data through agreements between participants, but the transparency of the data threatens the privacy of users. On the other hand, mixed net technology for protecting privacy protects privacy in distributed networks, but due to inefficient power consumption efficiency and processing speed issues, low cost, light weight, low power consumption Internet Hard to use. In this paper, we analyze the limitations of conventional mixed-net technology and propose a mixed-net technology method for low power consumption, high speed, and the Internet of things.