• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.252-253
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• 2017

본 논문에서는 벅-타입 능동 전력 디커플링 회로의 새로운 듀티 사이클 생성 방법을 제안한다. 기존의 듀티 사이클 생성방법에 비해 단순해진 듀티 사이클 계산 방식은 저성능 마이크로 프로세서에도 적합함과 동시에 보다 효과적으로 능동 전력 디커플링 회로를 제어할 수 있다. 제안하는 회로는 전류 불연속 모드로 동작하며, 전류 지령치는 DC링크 전류의 1차 리플 성분에 전류 이득을 보상하여 생성하기 때문에 모든 구간에서 효과적으로 DC링크의 전압 리플을 줄일 수 있다. 제안하는 듀티 사이클 생성 방법의 효과는 MATLAB-Simulink을 통해 검증하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.10
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• pp.691-699
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• 2014

In order to increase network lifetime, duty-cycle MAC protocols which can reduce energy consumption caused by idle listening is proposed for WSNs. In common duty-cycle MAC protocols, each sensor node calculates its duty-cycle interval based on the current amount of residual energy. However, in WSNs with the capability of energy harvesting, existing duty-cycle intervals based on the residual energy may cause the sensor nodes which have high energy harvesting rate to suffer unnecessary sleep latency. Therefore, a duty-cycle scheduling scheme which adjust the duty-cycle interval based on both of the residual energy and the energy harvesting rate was proposed in our previous work. However, since this duty-cycle MAC protocol overlooked the performance variation according to the change of duty-cycle interval and adjusted the duty-cycle interval only linearly, the optimal duty-cycle interval could not be obtained to meet application requirements. In this paper, we propose three methods which calculate the duty-cycle interval and analyse their results. Through simulation study, we verify that network lifetime, end-to-end delay and packet delivery ratio can be improved up to 23%, 44% and 31% as compared to the existing linear duty-cycle scheduling method, respectively.

• Journal of Software Assessment and Valuation
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• v.15 no.1
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• pp.103-107
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• 2019

Recently, many technologies have been developed to realize low power high speed digital data communication and one of them is related to duty cycle correction. In this paper, a low-area duty cycle correction circuit for a voltage-controlled ring generator is proposed. The duty cycle correction circuit is a circuit that corrects the duty cycle using a 180 degree phase difference of a voltage controlled ring oscillator. The proposed low-area duty cycle circuit changes a conventional flip-flop to a true single phase clocking (TSPC) flip-flop And a low-area high-performance circuit is realized. By using TSPC flip-flop instead of general flip-flop, it is possible to realize low-area circuit compared to existing circuit, and it is expected to be used for high-performance circuit for low-power because it is easy to operate at high speed.

• Journal of Internet Computing and Services
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• v.13 no.3
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• pp.23-30
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• 2012

In order to show the gap between theory and practice, this paper first gives some experimental results for theoretical and real neighbor sets on a test-bed sensor network. The results prove that existing management protocols (e.g., duty-cycling, routing or aggregation) based on the theoretical communication radius cannot achieve their original goal, efficiency. In this paper, we present a practical duty-cycling mechanism based on the real neighbor set, allowing for energy-efficiency. It also guarantees to suppress duplicated transmissions of sensing values with similarity within a specific threshold in each zone (i.e., a portion of intended divided network). Simulation results performed with a set of real sensor data show that our mechanism increases the network life time while guaranteeing the transmission of necessary sensing values.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.193-198
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• 2016

For environmental monitoring and risk identification of industrial plants, several monitoring systems using Wireless Sensor Networks (WSNs) have been developed. In this paper, we propose a dynamic duty cycle adjustment mechanism for reduced latency in industrial plants. The proposed method adjusts the duty cycle among predefined risk groups depending on the urgency of sensed data values. To demonstrate its efficacy, we analyze the expected transmission latency model and then discuss the characteristics in detail. We show that the proposed dynamic duty cycle mechanism is a more effective than a periodic mechanism by analyzing the expected latency of them in industrial plants where there are various types of sensory data with different levels of reliability.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.141-146
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• 2016

Geotechnial engineering projects that requires excavation activity can cause massive ground deformation and this can damage adjacent structures. Depending on the engineering characteristics of ground material and the excavation depth, the ground movement is various. To overcome this issue, the ground deformation is monitored by multiple sensors. Typically, an inclinometer is installed behind the support wall. In this paper, we present an adaptive duty-cycling control mechanism using wireless sensors for monitoring ground deformation in excavations. The proposed mechanism dynamically adjusts the sleep time based on the urgency degree of sensed data from inclinometer. Through analytical evaluation of expected latency time, we confirm our adaptive duty-cycling mechanism has lower latency compared with periodic duty-cycling mechanism under variable conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5C
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• pp.395-402
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• 2008

In this paper, an I/Q channel 12bits 40MS/s Pipeline Analog to Digital Converter that is able to apply to WLAN/WMAN system is proposed. The proposed ADC integrates DLL based duty-correction circuit which corrects the fluctuations in the duksty cycle caused by miniaturization of CMOS devices and faster operating speeds. It is designed as a 1% to 99% input clock duty cycle could be corrected to 50% output duty cycle. The prototype ADC is implemented in a $0.18{\mu}m$ CMOS n-well 1-poly 6-metal process and dissipates 184mW at 1.8V single supply The SNDR of the proposed 12bit ADC is 52dB and SFDR of 59dBc(@Fs=20MHz, Fin=1MHz) is measured.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.1
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• pp.103-110
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• 2015

WBAN(Wireless Body Area Network) is a Wireless Sensor Network for supporting various applications around body within 2~3m which consists of medical and non-medical device. MAC in WBAN environment should satisfy requirements such as low power consumption, various transmission rate, QoS, and duty-cycle, efficiently distribute frequency band, be strong at traffic load and save energy. This paper proposes AQ(Adaptive Queuing) MAC superframe structure for efficient energy use, considering the increase of traffic load. The simulation result also show that transmission rate and average MAC delay rate is improved comparing IEEE 802.15.4 MAC with AQ MAC.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.5
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• pp.772-778
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• 2018

Due to the recent advances in computing, communication and micro-electromechanical technology, Wireless Sensor Networks (WSNs) applications have been extended from military to many commercial areas such as object tracking, wire detection, and vehicular sensor networks. In some applications bursty data from many sensor nodes may be generated and the generated data from the monitoring area may be sent in a limited time to the final destination, sink node. In this paper, we present a BTF-MAC protocol adequate for WSNs applications in which bursty data packets are required to be transmitted in a limited time. The BTF-MAC is a synchronous duty-cycle MAC protocol and uses a slot-reserved and operational period extension mechanism adapted to the traffics. Our numerical analysis and simulation results show that BTF-MAC outperforms other related protocols such as DW-MAC and SR-MAC in terms of energy consumption and transmission delay.

• Annual Conference of KIPS
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• 2020.11a
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• pp.175-177
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• 2020

In multi-channel wireless sensor networks, optimizing data aggregation delay without any channels and timeslots conflicts has been concerned these days. The aggregation delay can be reduced by using different aggregation tree construction methods or scheduling in different methods in bottom-up or top-down manners. In this paper, we propose a new way of constructing aggregation tree purposing to decrease the total aggregation delay. The result shows that our proposed scheme can improve up to 64% comparing with state-of-the-art schemes.