• 한국전자파학회논문지
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• 제15권1호
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• pp.1-11
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• 2004

본 논문에서는 변복조(modulation/demodulation) 기능을 수행하는 스마트 안테나 기지국용 채널카드(channel card)를 실제 하드웨어로 구현하였다. 구현된 채널카드(channel card)는 우선적으로 각 구성 모듈의 기능 및 성능을 확인하였고, 완성된 채널카드를 스마트 안테나 시스템에 장착해 실제 필드 시험을 수행하여 성능을 확인하였다. 본 논문에서는 다중경로 페이딩이 존재하는 CDMA2000 1X 환경에서 채널카드의 성능을 필드 실험을 통해서 분석한 결과, DOA(Direction Of Arrival) 방향으로 정확한 빔패턴이 형성되는 것을 확인하였고, 채널카드가 내장된 스마트 안테나 시스템이 기존의 2안테나 다이버시티 시스템보다 FER(Frame Error Rate)이 5∼8배정도 우수하다는 것을 확인하였다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2003년도 가을 학술발표논문집 Vol.30 No.2 (1)
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• pp.196-198
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• 2003

Virtually every digital signal processors(DSPs) support on-chip multi- memory banks that allow the processor to access multiple words of data from memory in a single instruction cycle. Also, all existing fixed-point DSPs have irregular architecture of heterogeneous register which contains multiple register files that are distributed and dedicated to different sets of instructions. Although there have been several studies conducted to efficiently assign data to multi-memory banks, most of them assumed processors with relatively simple, homogeneous general-purpose resisters. Therefore, several vendor-provided compilers fer DSPs were unable to efficiently assign data to multiple data memory banks. thereby often failing to generate highly optimized code fer their machines. This paper presents an algorithm that helps the compiler to efficiently assign data to multi- memory banks. Our algorithm differs from previous work in that it assigns variables to memory banks in separate, decoupled code generation phases, instead of a single, tightly-coupled phase. The experimental results have revealed that our decoupled algorithm greatly simplifies our code generation process; thus our compiler runs extremely fast, yet generates target code that is comparable In quality to the code generated by a coupled approach

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.763-766
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• 2004

Recently, various acoustic artifacts that contains speaker have been produced such as cellular phone. Speaker consists of diaphragm generating sound and coil vibrating diaphragm. Generally, good speaker means that it has a wide frequency range, high output power rate to input power and flat sound pressure level in specified frequency range. Acoustic characteristic was estimated through the experiment and computer simulation, or sound power was controlled with acoustic sensitivity in a natural frequency range fer last decade. However, the flatness of sound pressure level has not been considered to enhance the sound quality of a speaker. Tn this study, a method for speaker design is proposed for a good acoustic characteristic, which is flatness of SPL(sound pressure level) and wideness between the first and second natural frequency. SYSNOISE is used fer acoustic analysis and ANSYS is used for harmonic response analysis and modal analysis. Optimization for acoustic characteristics of a speaker diaphragm is performed using ModelCenter. All analyses are done within a frequency domain. And we confirm that the experimental and computational simulations have similar trend.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.121-124
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• 2004

In this paper, we address an active vibration control system, which suppresses the vibration engaged by magnetically levitated stage. The stage system consists of a levitating platen with four permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force fer suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion via the vertical and horizontal forces. In the stage system, which represents the settling-time critical system. the motion of the platen vibrates mechanically. We designed an active vibration control system for suppressing vibration due to the stage moving. The command feedforward with inertial feedback algorithm is used fer solving stage system's critical problems. The components of the active vibration control system are accelerometers for detecting stage table's vibrations, a digital controller with high precise signal converters, and electromagnetic actuators.

• Tribology and Lubricants
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• 제35권3호
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• pp.151-157
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• 2019

Insulated oil degradation produces charged by-products, such as acids and hydro-peroxides, which tend to reduce the insulating properties of the oil. In this study, UV-vis spectroscopy measurement technology is developed and experimentally compared with other measurement methods, such as the titration method and IR spectroscopy, to validate its ability to monitor the degradation of electrical insulating paper. The degradation characteristics of the insulating paper are appropriately represented through various types of measurement methods, such as the Tan (delta) method, $CO_2$ gas production measurement, the titration method, and IR spectroscopy. The results are demonstrated to be well comparable to a change in the fluorescence emission ratio (FER), which is defined as the shift in fluorescence intensity in the measured wavelength range, and also to the chromatic ratio, which is defined as a color shift to longer wavelength ranges. The results also show that, by using UV-vis spectroscopy, it is possible to detect the degradation of the insulating paper. This study suggests that UV-vis spectroscopy can be applied as an alternative to high-performance liquid chromatography, which is the internationally recognized measurement technology for cellulose paper degradation. The FER detector is also verified to be useful as an effective condition-monitoring device for power transformers.

• PNF and Movement
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• 제11권2호
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• pp.103-110
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• 2013

Purpose : The aim of study was to assess the effect of backward walking combined with body weight supported treadmill training for patients with spinal cord injury. Methods : Forced vital capacity(FVC), forced expiratory volume at one second(FEV1), peak expiratory flow(PEF) and FEV1/FVC ratio(FER) were measured with a spirometer for on subject of T12 spinal cord injury. 10 meter walking test(10MWT), timed up & go test(TUG) and 6-Minute walking test(6MWT) were the measured. Intervention consisted of backward walking combined with body weight supported treadmill training five times a week for 12 weeks. Results : The date of 10MWT, TUG, 6MWT were improved. Furthermore, the date of PEF, FEV1, FVC, FER showed a improvement. Conclusion : Backward walking combined with body weight supported treadmill training may be a better and more effective method for gait performance and respiratory on incomplete spinal cord injury.

• 한국전자통신학회논문지
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• 제16권1호
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• pp.75-80
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• 2021

인공 지능은 놀라운 혜택을 제공하는 우리 삶의 중요한 부분이 되고 있다. 이와 관련하여 얼굴 표정 인식은 최근 수십 년 동안 컴퓨터 비전 연구자들 사이에서 뜨거운 주제 중 하나였다. 저해상도 이미지의 작은 데이터 세트를 분류하려면 새로운 소규모 심층 합성곱 신경망 모델을 개발해야 한다. 이를 위해 소규모 데이터 세트에 적합한 방법을 제안한다. 이 모델은 기존 심층 합성곱 신경망 모델에 비해 총 학습 가능 가중치 측면에서 메모리의 일부만 사용하지만 FER2013 및 FERPlus 데이터 세트에서 매우 유사한 결과를 보여준다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.200-203
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• 2021

본 논문은 여러 인공지능 기술 중 이미지 분류를 통한 사람의 얼굴 표정을 인식하는 프로그램을 통해 사람의 표정을 인식하여 거울에 나타내는 스마트미러 기술을 소개한다. 여러 사람의 5가지 표정이미지를 통하여 인공지능으로 학습하였고, 사람이 거울을 볼 때 거울이 그 표정을 인식하여 인식한 결과를 거울에 나타내는 방식이다. 여러 사람의 얼굴을 표정별로 구분되어있는 dataset을 kaggle에서 제공하는 fer2013을 이용하여 사용하였고, 이미지 데이터 분류를 위해 네트워크 구조는 컨볼루션 신경망 구조를 이용하여 학습하였다. 최종적으로 학습된 모델을 임베디드 보드인 라즈베리파이4를 통해서 얼굴을 인식하여 거울을 통해 디스플레이에 나타내는 구조이다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 추계학술대회
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• pp.613-617
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• 2021

서비스 산업의 성장과 함께 감정노동자의 스트레스가 사회적 문제로 인식되어 2018년 감정노동자 보호법이 시행되었다. 그러나 실질적인 감정노동자 보호 시스템의 부족으로 스트레스 관리를 위한 디지털 시스템이 필요한 시점이다. 본 논문에서는 대표적인 감정노동자인 고객 상담사를 위한 딥러닝 기반 스트레스 감지 시스템을 제안한다. 시스템은 실시간 얼굴검출 모듈, 한국인 감정 이미지 중심의 이미지 빅데이터를 딥러닝한 감정분류 FER 모듈, 마지막으로 스트레스 수치만을 시각화하는 모니터링 모듈로 구성된다. 이 시스템을 통하여 감정노동자의 스트레스 모니터링과 정신질환 예방을 목표로 설계하였다.

• Fisheries and Aquatic Sciences
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• 제5권3호
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• pp.229-234
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• 2002

Possibility of raising sunshine bass during the winter season in Korea was investigated. Also, the effect of feed on growth and body composition of sunshine bass was compared at the various salinity. Twenty sunshine bass $(Mean\;weight\;\pm S.D.\: :\;53.9 \pm 0.24 g)$ were stocked into the eighteen circular flow-through tanks. A 2 (feed) $\times$ 3 (salinity) factorial design with triplicate was used for this study. Feed was prepared into the 2 groups: the raw fish-based me>ist pellet (MP) containing $59.5\%$ crude protein and $9.4\%$ crude lipid, and commercial sinking red sea bream feed (CF) containing $49.9\%$ crude protein and $9.4\%$ crude lipid, respectively. And salinity was prepared into the 3 groups: freshwater $(0\%)$, brackishwater $(15\%)$, and seawater $(32\%)$. Fish were fed to satiation twice daily for 6 days a week. Fish were all survived at the end of the 8-week feeding trial. Weight gain (WG) and specific growth rate (SGR) of sunshine bass were significantly (P<0.05) affected by both feed and salinity. WG and SGR of sunshine bass fed the MP were significantly (P<0.05) higher than those of fish fed the CF in the same salinity. Amount of dry feed fed was significantly (P<0.05) affected by both feed and salinity. Feed consumption by sunshine bass fed on the MP was significantly (P<0,05) higher than by fish fed on the CF in the same salinity. Feed efficiency ratio (FER) was significantly (P<0,05) affected by salinity, but not by feed. Protein efficiency ratio (PER) was significantly (P<0.05) affected by both feed and salinity. Moisture and protein content of the whole-body of fish was not significantly (P>0.05) affected by either feed or salinity. However, lipid and ash content of the whole-body of fish was significantly (P<0.05) affected by salinity, but not by feed. In conclusion, the MP was superior to CF for growth of sunshine bass during the winter season in Korea and no mortality occurred. And sunshine bass seemed to grow better in freshwater $(0\%)$ and brac-kishwater $(15\%)$ than seawater $(32\%)$ under these experimental conditions, in terms of improvement in FER and PER in freshwater or brackishwater.