• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.6
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• pp.847-853
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• 2016

Applications of Si have been increasingly exploited and extended to More-Moore, More-than-Moore, and beyond-CMOS approaches. Ge is regarded as one of the supplements for Si owing to its higher carrier mobilities and peculiar band structure, facilitating both advanced and optical applications. As an emerging metal-oxide device, the junctionless field-effect transistor (JLFET) has drawn considerable attention because of its simple process, less performance fluctuation, and stronger immunity against short-channel effects due to the absence of anisotype junctions. In this study, we investigated lateral field scalability, which is equivalent to channel-length scaling, in Si and Ge JLFETs. Through this, we can determine the usability of Si CMOS and hypothesize its replacement by Ge. For simulations with high accuracy, we performed rigorous modeling for ${\mu}_n$ and ${\mu}_p$ of Ge, which has seldom been reported. Although Ge has much higher ${\mu}_n$ and ${\mu}_p$ than Si, its saturation velocity ($v_{sat}$) is a more determining factor for maximum $I_{on}$. Thus, there is still room for pushing More-Moore technology because Si and Ge have a slight difference in $v_{sat}$. We compared both p- and n-type JLFETs in terms of $I_{on}$, $I_{off}$, $I_{on}/I_{off}$, and swing with the same channel doping and channel length/thickness. $I_{on}/I_{off}$ is inherently low for Ge but is invariant with $V_{DS}$. It is estimated that More-Moore approach can be further driven if Si is mounted on a JLFET until Ge has a strong possibility to replace Si for both p- and n-type devices for ultra-low-power applications.

• Journal of IKEEE
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• v.23 no.3
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• pp.954-961
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• 2019

This paper suggests an advanced 8T SRAM which can operate properly in subthreshold voltage regime. The memory cell consists of symmetric 8 transistors, in which the latch storing data is controlled by a column-wise assistline. During the read, the data storage nodes are temporarily decoupled from the read path, thus eliminating the read disturbance. Additionally, the cell keeps the noise-vulnerable 'low' node close to the ground, thereby improving the dummy-read stability. In the write, the boosted wordline facilitates to change the contents of the memory bit. At 0.4 V supply, the advanced 8T cell achieves 65% higher dummy-read stability and 3.7 times better write-ability compared to the commercialized 8T cell. The proposed cell and circuit techniques have been verified in a 16-kbit SRAM array designed with an industrial 180-nm low-power CMOS process.

• Journal of Communications and Networks
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• v.5 no.4
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• pp.386-393
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• 2003

Future wireless networks are expected to achieve high bit rates at low cost, enabling multimedia and QoS-based services over the wireless medium. The impulse radio ultra-wide band (IR-UWB) technique is a promising candidate in the deployment of such networks, thanks to its potential robustness and capacity. In the past, most of the UWB research focused on hardware and physical layer aspects in order to solve the technological challenges posed by IR-UWB. UWB peculiar characteristics may, however, also stimulate innovative higher layers’ design. This work addresses MAC issues for UWB communication systems. Key areas such as medium sharing, MAC organization, packet scheduling and power control are reviewed. The impact of UWB on the above functions is discussed, and areas which require UWB specific design are identified. Finally, novel MAC functions enabled by UWB specific features, i.e., precise ranging and positioning, are presented.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.479-482
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• 2003

We propose a real time gas monitoring system for classifying various gases with different concentrations. Using thermal modulation of operating temperature of two sensors, we extract patterns of gases from the voltage across the load resistance. We adopt the relative resistance as a pre-processing method and an ART2 neural network as a pattern recognition method. The proposed method has been implemented in a real time embedded system with tin oxide gas sensors, TGS 2611, 2602 and an MSP430 ultra-low power microcontroller in the test chamber.

• Journal of Sensor Science and Technology
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• v.19 no.1
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• pp.43-51
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• 2010

In this study, wearable ECG measurement system was implemented for health monitoring during daily life. A wearable belt-type ECG electrode worn around the chest by measuring the real-time ECG is produced in order to minimize the inconvenience in wearing. The measured ECG signal is transmitted via an ultra low power consumption wireless data communications unit to personal computer using Zigbee-compatible wireless sensor node. The ECG monitoring program is developed at end user which is personal computer. The measured ECG contains many noises mainly due to motion artifacts. For ECG signal processing, adaptive filtering process is proposed which can reduce motion artifacts efficiently and accurately than digital filter. The experimental results show that a reliable performance with high quality ECG signal can be achieved using this wearable ECG monitoring system.

• Vacuum Magazine
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• v.4 no.1
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• pp.4-11
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• 2017

The Rare Isotope Science Project (RISP) has been launched for developing a superconducting heavy-ion linear accelerator, which produces various rare isotopes for low energy nuclear science and applied sciences. This superconducting linac is designed to achieve a very high beam current (200Mev/u with 400 kW beam power) of heavy ions including Uranium. For the high current accelerator, the requirement of ultra high-vacuum level is considered as one of the of important factors. Vacuum calculations have been carried out to verify the vacuum system design satisfied the requirements. In this paper, an overview of RISP and vacuum calculation methods for several interesting sections of the superconducting linear accelerator.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1579_1580
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• 2009

다양한 환경에서 WBAN/USN 시스템이 적용됨에 따라 해당 시스템의 효율적인 전력 운용 및 통신 방식이 중요해 지고 있다. 이에 본 논문은 센서 간 효율적인 운용 방식으로 ID 기반의 통신 시스템을 제안 하였다. 보다 효율적인 시스템 동작을 위해 센서 노드에 웨이크업 모듈과 자가 전원 차단 회로를 구현함으로써 센서 노드의 보다 효율적인 전력 사용이 가능하도록 하였다. 웨이크업 모듈 구현을 통해 싱크노드가 원하는 센서 노드만 동작 가능하도록 하였으며, 일반적인 센서노드와는 달리 센서 데이터 전송 후 시스템 전력을 차단하는 회로를 구현함으로써 시스템의 불용 전력을 최소화 하였다. 또한 제안한 시스템을 직접 제작하고 실제 ID 기반으로 통신이 가능한지 검증함으로써 다양한 WBAN/USN 시스템에 적용 가능함을 보였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1568_1569
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• 2009

RFID 수동 태그의 동작 원리를 이용하여 USN/WBAN 센서 노드 시스템에 적용 가능한 웨이크 업 회로를 설계하였다. 웨이크 업회로 구성은 크게 전압 체배기, 복조기, 상태기계로 구성되었다. 상태 기계에 동작 가능한 전압을 공급하기 위해 전압 체배기는 문턱 전압 제거 방식을 적용한 구조를 사용하였고, 복조기 회로로는 AM 복조기로 구조가 간단한 포락선 검파기 방식을 사용하였다. 전압 체배기에 높은 전압이 인가될 경우 회로가 파괴되는 것을 막기 위해 제한 회로를 구성하여 최대 전압을 2.1V로 제한하였다. 또한 복조기에서는 안정적인 데이터 복조를 위해 비교기의 기준전압을 입력신호의 평균값을 사용한 슈미트 트리거 비교기를 사용하여 안정적으로 데이터를 추출하였다. 삼성 0.18um CMOS 공정을 이용하여 설계하였고, 측정 결과 전압 체배기의 체배 전압은 2.07~1.76V까지 체배 되는 것을 확인하였고, 복조기의 데이터 복조 역시 약 4M의 거리까지 데이터를 복조함을 확인하였다.

• Journal of the Korean Graphic Arts Communication Society
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• v.15 no.2
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• pp.57-76
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• 1997

A color halftoning is the process of generating halftone images for the different color plans, for example, cyan, magenta, yellow, and black for a offset printing device. A conventional halftone technique, so called AM screening, is simple and easy to implement, but the halftoned dot patterns by using this method is not free for the moire` fringe. Moire` patterns are caused the power spectrum distribution on low spatial frequency domain. To avoid Moire` patterns, the conventional screen require the different screen angles for each color plans. Recently, Ultra-fine and 7 color printing methods are developed to expend the color gamut. In 7 color printing method must be used the halftone technique of random and blue noise characteristic to avoid Moire` fringe.

• Bulletin of the Korean Space Science Society
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• 1993.04a
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• pp.17-17
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• 1993

태양의 전자파 복사와 입자의 방출은 지구자기구에 변화를 주어 여러 종류의 플라즈마를 발생시킨다. 관측되는 플라즈마파중에서 주파수가 가장 낮은 영역의 파를 극초저주파수 파동(Ultra Low Frequency pulsation)이라 부르며 주기는 수 초에서 수십 분에 이른다. 본 연구에서는 자기권 내부에 존재하는 플라즈마구 영역(L <5)에서 발생되는 주기가 10 \ulcorner45초인 Pc 3파를 다룬다. 210˚ 자기자오선상에 위치한 Kagoshima(KAG. L=1.22), Chichihima(CBI, L=1.44), Birdsvile(BSV, L=1.57) Adelaide(ADE, L=2.13)관측소에서 1990년 7월27일 잡음정도가 0.1nT rms인 fluxgate 자기계측기를 사용하여 측정하였으며 이 자료를 이용하여 Pc 3파의 Power Spectrurn을 구하고 자기위도 변화에 따른 Pc 3파간의 상관성을 알아본다.