http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A 3.5 GHz Spread-Spectrum Clock Generator With a Memoryless Newton-Raphson Modulation Profile
Sewook Hwang,Minyoung Song,Young-Ho Kwak,Inhwa Jung,Chulwoo Kim IEEE 2012 IEEE journal of solid-state circuits Vol.47 No.5
<P>A frequency-locked loop (FLL) based spread-spectrum clock generator (SSCG) with a memoryless Newton-Raphson modulation profile is introduced in this paper. The SSCG uses an FLL as a main clock generator. It brings not only an area reduction to the SSCG but also the advantage of having multiple frequency deviations. A double binary-weighted DAC is proposed that modulates the frequency information of the frequency detector using a 1-1-1 MASH ΔΣ modulator. The Newton-Raphson mathematical algorithm is applied to the proposed profile generator in order to generate the optimized nonlinear profile without needing any memory, resulting in a reduction in the area and the power consumption. It also makes it possible to have multiple modulation frequencies. The SSCG can support 14 frequency deviations of ±0.5% to 3.5% in steps of 0.5% and three modulation frequencies of <I>f</I><SUB>m</SUB>, 2 <I>f</I><SUB>m</SUB> and 3 <I>f</I><SUB>m</SUB>. It achieved an EMI reduction of 19.14 dB with a 0.5% down spreading and a 31 kHz modulation frequency, while employing a core area of 0.076 mm<SUP>2</SUP> in a 0.13-μm CMOS process and consuming 23.72 mW at 3.5 GHz.</P>
Sewook Hwang,Jabeom Koo,Kisoo Kim,Hokyu Lee,Chulwoo Kim IEEE 2013 IEEE transactions on circuits and systems. a publi Vol.60 No.9
<P>This paper presents a temperature sensor based on a frequency-to-digital converter with digitally controlled process compensation. The proposed temperature sensor utilizes ring oscillators to generate a temperature dependent frequency. The adjusted linear frequency difference slope is used to improve the linearity of the temperature sensor and to compensate for process variations. Furthermore, an additional process compensation scheme is proposed to enhance the accuracy under one point calibration. With one point calibration, the resolution of the temperature sensor is 0.18 <SUP>°</SUP>C/LSB and the maximum inaccuracy of 20 measured samples is less than ±1.5<SUP>°</SUP>C over a temperature range of 0<SUP>°</SUP>C ~ 110<SUP>°</SUP>C. The entire block occupies 0.008 mm<SUP>2</SUP> in 65 nm CMOS and consumes 500 μW at a conversion rate of 469 kS/s.</P>
A Self-Calibrated DLL-Based Clock Generator for an Energy-Aware EISC Processor
Sewook Hwang,Kyeong-Min Kim,Jungmoon Kim,Seon Wook Kim,Chulwoo Kim IEEE 2013 IEEE transactions on very large scale integration Vol.21 No.3
<P>This paper describes a low-jitter delay-locked loop (DLL)-based clock generator for dynamic frequency scaling in the extendable instruction set computing (EISC) processor. The DLL-based clock generator provides the system clock with frequencies of 0.5× to 8× of the reference clock, according to the workload of the EISC processor. The proposed analog self-calibration method and a phase detector with an auxiliary charge pump can effectively reduce the delay mismatch between delay cells in the voltage-controlled delay line and the static phase offset due to the current mismatch in the charge pump, respectively. The self-calibrated output waveform exhibits 9.7 ps of RMS jitter and 73.7 ps of peak-to-peak jitter at 120 MHz. The prototype clock generator implemented in a 0.18-μm CMOS process occupies an active area of 0.27 mm<SUP>2</SUP> and consumes 15.56 mA.</P>
Sewook Hwang,Junyoung Song,Yeonho Lee,Chulwoo Kim IEEE 2017 IEEE Transactions on Circuits and Systems I: Regul Vol.64 No.10
<P>We present a 1.62-5.4-Gb/s receiver for DisplayPort version 1.2a and propose an adaptive equalizer (EQ) with a peak-level comparison technique for eye measurement. A single comparator and an up/down unmatched-current charge pump are used to realize a simpler EQ architecture with low power dissipation. A referenceless frequency acquisition technique is also proposed. A time-to-digital converter-based pulsewidth detector supports the referenceless frequency acquisition within the range of 1.62-5.4 Gb/s. An XOR-gate-embedded charge pump and a half-rate linear phase detector were used to improve the jitter tolerance (JTOL) performance. The measured eye opening of the proposed EQ at 5.4 Gb/s was 0.68 UI with a -20-dB loss channel. The proposed receiver passed all the JTOL tests of the DisplayPort compliance specification version 1.2b. The power consumption of the receiver was 36.8 mW at 5.4 Gb/s. The receiver occupied a core area of 0.265 mm(2) using 65-nm CMOS process technology.</P>
An Add-On Type Real-Time Jitter Tolerance Enhancer for Digital Communication Receivers
Sewook Hwang,Junyoung Song,Sang-Geun Bae,Yeonho Lee,Chulwoo Kim IEEE 2016 IEEE transactions on very large scale integration Vol.24 No.3
<P>An add-on type real-time jitter tolerance enhancer (JTE) is presented in this paper. The proposed JTE can improve high-frequency jitter tolerance (JTOL) by using a real-time phase alignment scheme. A mathematical analysis for an advanced bit error rate (BER) prediction method is also introduced. The proposed circuit is applicable to various types of receivers, such as referenceless receivers, receivers with a reference clock source, and source-synchronous receivers. The referenceless receiver with the proposed JTE achieved an out-of-band JTOL of 0.71 UIpp at 100 MHz with <10(-12) BER. This is 196% higher than a conventional receiver without the JTE. The source-synchronous receiver with the proposed JTE achieved 0.92 UIpp at 300 MHz with <10(-12) BER. Total core areas of the receiver and JTE are 0.19 and 0.07 mm(2) in a 0.13-mu m CMOS process, respectively. The power consumption of the receiver is 38 mW at 5.4 Gbit/s, and the JTE dissipates 22 mW.</P>
The Effectiveness of Rest Frame on Virtual Reality Sickness
( Sewook William Oh ),( Ki Hong Kim ) 한국감성과학회 2017 한국감성과학회 국제학술대회(ICES) Vol.2017 No.-
Simulator sickness, or Virtual Reality(VR) sickness is the biggest drawback among the known issues of virtual reality, which occurs when the sensory inputs indicating self-motion are not in agreement with each other. Rest frame is one of the methods which are used to reduce VR sickness, such as motion platform or field of view adjustment. Many papers used the rest frame as a mean to deal with VR sickness, but only used rectangle-based shapes. In this paper, we compared the widely used rectangular rest frame to the different shapes of rest frames in order to find whether the shape of the rest frame affects the severity of VR sickness. We used 3x3 rectangular-grid-shaped rest frame from the latest paper as the reference. The other rest frames were chosen from different shape groups: X, circular, and diamond shapes. The participants wearing the Head-Mounted Display as a viewer of a character travelled through the predefined path through the city of Paris at the speed of 50 m/sec for duration of 5 minutes, with different rest frames applied at each time. Our results showed that the rest frame which drew a participant's attention to the center of viewpoint, which was the “X” shaped rest frame, significantly reduced the VR sickness compared with the others. But some of the participants reported that the “X” shaped rest frame was also drawing too much attention, which led to hard time watching the actual VR scene. Minimizing this side effect will be addressed.
Midline dermoid cyst of the upper lip: case report
Sewook Koh 대한구강악안면외과학회 2011 대한구강악안면외과학회지 Vol.37 No.5
Midline craniofacial dermoids are rare lesions resulting from the abnormal fusion of embryologic structures. The clinical features of craniofacial dermoid cysts show a range of presentations, including infection, asymptomatic puncti, or seizure secondary to intracranial invasion. Appropriate management involves an accurate diagnosis of the dermoid cyst and a complete resection.
오세욱(Sewook Oh),이길호(Gilho Lee),김동근(Donggeun Kim) 한국지반환경공학회 2013 한국지반환경공학회논문집 Vol.14 No.6
본 논문에서는 친환경고화재와 자연토, 물을 혼합하여 포설한 후 다짐장비를 이용하여 지반을 고결시키는 임도포장공법에 대한 기초연구를 수행하였다. 포장체의 목표강도는 2.0MPa로 설정하였고 고화재의 혼합비, 자연토의 종류, 양생기간별로 공시체를 제작하여 일축압축강도특성과 내구성을 평가하였다. 일축압축강도시험은 동일한 혼합비의 시멘트를 혼합한 공시체와 친환경고화재를 혼합한 공시체를 제작하여 강도를 비교하였으며, 내구성 평가를 위한 시험은 표면마모시험, 유수저항성 시험 등을 수행하였다. 또한, 임도의 특성상 탐방객들도 이용이 가능하므로 보행만족도를 평가하기 위하여 쇠구슬과 골프공을 이용한 SB, GB시험을 수행 하였다. This study carried out fundamental study on the forest road pavement method of cementing the ground using the compaction equipment after laying by mixing with eco-friendly stabilizer, natural soil and water. Target strength of pavement was set to 2.0MPa and the specimen was produced per mixing ratio of cement, kinds of natural soil and curing period to evaluate the durability and unconfined compressive strength. Unconfined compressive strength test was conducted to compare strength by producing the test specimen mixing environment-friendly cement as well as the test specimen mixing cement with the same mixing ratio. To evaluate the durability, surface abrasion test and water flow resistance test were conducted. In addition, SB and GB tests were conducted using iron marble and golf ball to evaluate the walking satisfaction since it can be used by visitors due to the feature of forest road.