• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.777-785
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• 2009

In recent wireless sensor networks, stationary nodes and mobile nodes co-exist to provide a diverse service. However, because there are multiple mobile nodes located in the wireless sensor network, there is a potential for the instability due to the frequent network reconfiguration and the traffic caused by densely concentration of mobile nodes while mobile nodes are switching locations. In order to solve this problem, we propose the pumping node architecture to solve this traffic congestion problem due to the crowds of mobile nodes. The pumping node can be reduced heavy traffic by pumping through the backbone network caused by the densely concentration of the mobile nodes. As a result, the architecture reduces the traffic in the sensor network with high reliability.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.4
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• pp.32-38
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• 2011

This paper describes implementation of the 5.0GHz RF frequency synthesizer with 0.18${\mu}m$ silicon CMOS technology being used as an application of the IEEE802.15.4 USN sensor node transceiver modules. To get good performance of speed and noise, design of the each module like VCO, prescaler, 1/N divider, fractional divider with ${\Sigma}-{\Delta}$ modulator, and common circuits of the PLL has been optimized. Especially to get excellent performance of high speed and wide tuning range, N-P MOS core structure and 12 step cap banks have been used in design of the VCO. The chip area including pads for testing is $1.1{\times}0.7mm^2$, and the chip area only core for IP in SoC is $1.0{\times}0.4mm^2$. Through analysing of the fabricated frequency synthesizer, we can see that it has wide operation range and excellent frequency characteristics.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.87-93
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• 2008

This paper describes implementation of the 5.0GHz RF frequency synthesizer with $0.18{\mu}m$ silicon CMOS technology being used as an application of the IEEE802.15.4 USN sensor node transceiver modules. To get good performance of speed and noise, design of the each module like VCO, prescaler, 1/N divider, fractional divider with ${\Sigma}-{\Delta}$ modulator, and common circuits of the PLL has been optimized. Especially to get good performance of speed, power consumption, and wide tuning range, N-P MOS core structure has been used in design of the VCO. The chip area including pads for testing is $1.1*0.7mm^2$, and the chip area only core for IP in SoC is $1.0*0.4mm^2$. Through comparing and analysing of the designed two kind of the frequency synthesizer, we can conclude that if we improve a litter characteristics there is no problem to use their as IPs.

• Journal of Advanced Navigation Technology
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• v.10 no.3
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• pp.268-275
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• 2006

The rapid proliferation of in-home and office information applications and services is driving the need for new wireless technologies enabling wideband short range multimedia communications. Due to the growing demand for higher quality media and faster wireless connections, several IEEE standardization groups are considering very high data rate alternatives physical layer(s) for Wireless Personal Area Network (WPAN). The Ultra Wide Band (UWB) multiple access technology based on very narrow pulse transmission, is one viable candidate for these applications providing very high bit rates services, low power consumption and accurate positioning capability. In this paper we provide a methodology to evaluate the UWB system BER performance in UWB wireless fading networks with power controlled UWB devices are considered. Results can be used to analyze the performance of a given network topology and to provide useful design ideas for an UWB home sensor network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.223-228
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• 2017

In this paper, we are proposing an optimal design of wideband pulsed type gamma-ray sensors. These sensors were manufactured based on the design results and after word electrical properties were analyzed. The sensor input parameters were derived on the basis of pulsed gamma-ray spectrum and time-dependent energy rate, and the output current which were derived on the basis of the sensor sensitivity control circuit. Pulsed gamma-ray sensors were designed using the TCAD simulators. The design results show that the optimal Epi layer thickness is 45um with the applied voltage 3.3V and the diameter is 2.0mm. The doping concentrations are as follows : N-type is an Arsenic as $1{\times}10^{19}/cm^3$, P-type is a Boron as $1{\times}10^{19}/cm^3$ and Epi layer is Phosphorus as $3.4{\times}10^{12}/cm^3$. The fabricated sensor was a leakage current, 12pA at voltage -3.3V and fully depleted mode at voltage -5V. A test result of pulsed radiation shows that the sensor gives out the optimal photocurrent.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1121-1124
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• 2015

In this paper, we propose and demonstrate an optimal design of wideband pulsed gamma-ray detectors. Pulsed gamma-ray detectors are designed to operate in a dose rate of $1{\times}10^6{\sim}1{\times}10^8rad(Si)/s$. The input parameter was derived based on the energy ratio of pulse gamma-ray spectrum and the time of the energy. The sensor output current was calculated based on the dose rate control circuit. Using the N-type Epi Wafer, the optimum condition detection sensor was designed based on TCAD. The simulation results show that the optimal Epi layer thickness is 45um when applied voltage 3.3V. The doping concentrations are as follows : N-type is an Arsenic as $1{\times}10^{19}/cm^3$, P-type is a Boron as $1{\times}10^{19}/cm^3$ and Epi layer is Phosphorus as $3.4{\times}10^{12}/cm^3$. Pulse gamma-ray detector diameter is the 1.3mm.

• The Journal of the Acoustical Society of Korea
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• v.26 no.4
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• pp.173-181
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• 2007

In this paper, we propose a moving target localization algorithm using acoustic spectrograms. A time-versus-frequency spectrogram provide a information of trajectory of the moving target in underwater. For a source at sufficiently long range from a receiver, broadband striation patterns seen in spectrogram represents the mutual interference between modes which reflected by surface and bottom. The slope of the maximum intensity striation is influenced by waveguide invariant parameter ${\beta}$ and distance between target and sensor. When more than two sensors are applied to measure the moving ship-radited noise, the slope and frequency of the maximum intensity striation are depend on distance between target and receiver. We assumed two sensors to fixed point then form a circle of apollonios which set of all points whose distances from two fixed points are in a constant ratio. In case of three sensors are applied, two circle form an intersection point so coordinates of this point can be estimated as a position of target. To evaluates a performance of the proposed localization algorithm, simulation is performed using acoustic propagation program.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.679-680
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• 2012

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1843-1844
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• 2003

154 kV급 가스절연개폐장치(GIS)용dp 장착할 수 있는 내장형 극초단파 (UHF) 부분방전(PD) 센서의 고주파 특성을 전산모사 하였다. UHF PD 센서는 일종의 광대역 안테나이므로 3차원 전자기장 해석도구를 활용하여 주파수 또는 시간 영역에서 고주파특성을 해석하였다. 센서의 구조를 결정하는 센서장착용 구멍과 센서의 크기를 변수로 조절하면서 내장형 UHF PD 센서의 특성을 해석 하였다. 센서가 장착되는 구멍의 크기와 센서의 구조변화에 따라 반사손실이 변화하였으며 GIS의 전파 mode의 영향을 받는다.

• KIPE Magazine
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• v.14 no.1
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• pp.26-33
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• 2009

광대역 반도체중에서도 SiC(Silicon Carbide)는 우수한 전기적, 기계적, 열적, 화학적, 광학적 그리고 생체 적합성 등으로 인하여 지난 반세기 동안 급속히 발전하고 있는 SiM/NEMS(Micro/Nano Electro Mechanical System)를 대처할 수 있는 차세대 M/NEMS로써 고온, 고압, 고진동, 고습도 등의 극한 환경에서도 사용 가능한 자동차, 선박, 우주항공, 산업 프랜트용 마이크로 센서 및 액츄에이터, 초고주파수 정보통신용 부품 그리고 바이오 센서 등의 분야에 크게 주목을 받고 있다. 본 논문에서는 현재 SiC M/NEMS의 연구개발 현황에 대해서 소개하고자 한다.