• 한국정보통신학회논문지
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• 제26권3호
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• pp.355-366
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• 2022

본 논문은 프로그램 가능한 구조를 사용하여 재구성이 가능하고 저 전력 초소형의 장점을 모두 제공하는 인공지능 가속기를 위한 마이크로코드 기반 뉴럴 네트워크 가속기 컨트롤러를 제안한다. 대상 가속기가 다양한 뉴럴 네트워크 모델을 지원하도록 마이크로코드 컴파일러를 통해 뉴럴 네트워크 모델을 마이크로코드로 변환하여 가속기의 메모리 접근과 모든 연산기를 제어할 수 있다. 200MHz의 System Clock을 기준으로 설계하였으며, YOLOv2-Tiny CNN model을 구동하도록 컨트롤러를 구현하였다. 객체 감지를 위한 VOC 2012 dataset 추론용 컨트롤러를 구현할 경우 137.9ms/image, mask 착용 여부 감지를 위한 mask detection dataset 추론용으로 구현할 경우 99.5ms/image의 detection speed를 달성하였다. 제안된 컨트롤러를 탑재한 가속기를 실리콘칩으로 구현할 때 게이트 카운트는 618,388이며, 이는 CPU core로서 RISC-V (U5-MC2)를 탑재할 경우 대비 약 65.5% 감소한 칩 면적을 제공한다.

• 대한전자공학회논문지SD
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• 제41권7호
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• pp.37-41
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• 2004

We have formulated an empirical analytic model for the static characteristics of implanted vertical-cavity surface-emitting lasers (VCSELs). Specifically, we have derived analytic formulas for the threshold current, slope efficiency, dynamic resistance, and the output power and forward voltage at the operation current of 12 ㎃ in terms of the implant and metal-aperture radii by fitting the measured results. The radii of the metal aperture and implant mask of the 850 nm VCSELs range from 4 to 12.5 ${\mu}{\textrm}{m}$ and 7 to 17.5 ${\mu}{\textrm}{m}$ respectively. The model shows the way of tailoring the VCSEL characteristics by changing the mask dimensions only.

• Journal of electromagnetic engineering and science
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• 제9권4호
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• pp.202-210
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• 2009

In this paper, we have analyzed the effect of interference between ultra-wideband(UWB) and intelligent transport systems(ITS). The maximum possible UWB emission power and minimum possible distance between UWB devices and ITS are found. In order to analyze the interference, we employ the Monte-Carlo(MC) method. We consider six situations, which are indoor office line-of-sight(LOS), indoor office non-line-of-sight(NLOS), indoor residential LOS, indoor residential NLOS, outdoor rural LOS, and outdoor rural NLOS environments. From the simulation results, it is confirmed that coexistence between UWB and ITS devices can be realized in accordance with the emission mask of 19.3 dB for indoor application or 19.3 dB for an image system. And in the outdoors, coexistence between UWB and ITS devices can be realized if the emission mask is at least 1.6 dB for vehicles' radar systems.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.989-992
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• 1997

The objective of this study is to develop stencil cutting process and determine optimal conditions which make good-quality stencil by using a Nd:YAG laser. The effects of process parameters such as laser power, type of mask, gas pressure, cutting speed and pulse width on the cut edge quality were investigated. In order to analyze the cut surface characteristics(roughness, kerf width, dross) optical microscopy, SEM photography and roughness test were used. A a results, the optimal conditions of process parameters were determined, and the practical feasibility of the proposed system is also examined by using a commercial gerber file for PCB stencil manufacturing.

• Journal of Welding and Joining
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• 제18권4호
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• pp.64-69
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• 2000

Reliability of PBGA(Plastic Ball Grid Array) package is very weak compared with normal plastic packages. The reliability are the lower resistance to popcorn cracking, which is reduced by moisture absorption in PCB(Printed Circuit Board). This paper adapts plasma treatment process and analyzes their effect. The contents of C and Cl decrease after plasma treatment but O, Ca and N relatively increase. The Plasma treatment to improve the adhesion between EMC(Epoxy Molding Compound) and PCB(solder mask). The degree of improvement was over 100% Max., which is depend on the properties of EMC. Ar+H$_2$as plasma gas show good result. There is a little difference in RF power and treatment time.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.145.1-145.1
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• 2014

변형된 end-Hall type의 이온 소스를 사용하여 이온 소스의 형태에 따라 달라지는 이온 빔의 변화를 측정하였다. 이온 소스 cathode의 wehnelt mask를 세 가지 종류로 제작하였으며, 생성된 이온 빔을 이용하여 Al이 sputter 방식으로 증착된 유리 기판을 etching 하였다. 실험 결과 wehnelt mask의 모양에 따라 focus, broad, strate의 형태로 이온 빔이 생성되는 것을 확인하였다. Al이 증착된 유리 기판의 제작을 위하여 Al target을 사용하여 RF power로 150 W, 2분간 sputtering을 하였고, 이온 소스와 기판사이의 거리를 1 cm씩 증가시켜가며 이온 빔을 2,500 V로 3분간 유리 기판을 etching한 후, 유리 기판이 etching된 모양을 통해 이온 빔의 형태를 분석하였다. 본 연구를 위하여 sputtering과 이온 빔 처리가 가능한 챔버를 제작하였으며, scroll pump와 turbo molecular pump를 사용하였다. Base pressure $1.5{\times}10^{-6}Torr$에서 실험이 진행되었고, 불활성 기체 Ar을 사용하였다. Ar 기체를 주입시 pressure는 $2.6{\times}10^{-3}Torr$였다.

• 한국레이저가공학회지
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• 제4권2호
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• pp.47-57
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• 2001

This study deals with the laser cutting of stencil for the PCB. The most important aim of this study is to determine optimal conditions which make good-qualify stencil in Nd:YAG laser cutting. We made an experiment according to various variables (power. type of mask. gas pressure, cutting speed, and pulse width) and analyzed the cutting characteristics (surface roughness, kerf width. dross) . Each variable has optimal value for good-qualify cut edge under fixed condition. And neural network after learning experimental data with a million time iteration could predict surface roughness of cut edge under arbitrary condition approximately.

• Journal of the Optical Society of Korea
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• 제12권3호
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• pp.192-195
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• 2008

We report on the spatial information of a coupling laser transfer into a reflected probe laser; the transfer is achieved by means of electromagnetically induced transparency through a common excited state connected with $5S_{1/2}-5P_{1/2}(F=1{\rightarrow}F'=2)$ in the $^{87}Rb\;D_1$ line. When the coupling laser was spatially modulated as a stationary wave, the absorption of the probe laser was enhanced and the reflection of the probe laser was generated. When the coupling laser was spatially modulated by a mask, we observed that the reflection light of the probe laser was modulated as the shape of the mask. The Bragg reflection transferred the spatial information of the coupling laser. The reflection was approximately 7% of the incident power of the probe laser.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.370-373
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• 2009

X-ray lithography was employed to fabricate ITO-less high resolution sustain electrodes for plasma display panel (PDP). A polyimide film based X-ray mask and Xray sensitive Ag electrode paste were fabricated to check their effect on the patterning of Ag electrodes with less than 30 ${\mu}m$ in width. The X-ray lithographic method was found to be useful for the high resolution sustain electrode patterns due to the high penetration power and low scattering property of X-ray source.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.399-402
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• 2004

This paper presents a system-on-chip prototype implementing a full integration for a portable digital audio system. The chip is composed of a audio processor block to implements audio decoding and voice compression or decompression software, a system control block including 8-bit MCU core and Memory Management Unit (MMU) a low power 16-bit ${\Sigma}{\Delta}$ CODEC, two DC-to-BC converter, and a flash memory controller. In order to support other audio algorithms except Mask ROM type's fixed codes, a novel 16-bit fixed-point DSP core with the program-download architecture is proposed. Funker, an efficient power management technique such as task-based clock management is implemented to reduce power consumption for portable application. The proposed chip has been fabricated with a 4 metal 0.25um CMOS technology and the chip area is about 7.1 mm ${\times}$ 7.1mm with 100mW power dissipation at 2.5V power supply.