• ETRI Journal
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• 제31권6호
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• pp.703-708
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• 2009

Silicon antimony films are studied as resistors for uncooled microbolometers. We present the fabrication of silicon films and their alloy films using sputtering and plasma-enhanced chemical vapor deposition. The sputtered silicon antimony films show a low 1/f noise level compared to plasma-enhanced chemical vapor deposition (PECVD)-deposited amorphous silicon due to their very fine nanostructure. Material parameter K is controlled using the sputtering conditions to obtain a low 1/f noise. The calculation for specific detectivity assuming similar properties of silicon antimony and PECVD amorphous silicon shows that silicon antimony film demonstrates an outstanding value compared with PECVD Si film.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.630-633
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• 2007

This paper proposes method to find the subjective satisfaction index of an air-conditioner using consumer's sensory evaluation for an air-conditioner. A satisfaction index of an air-conditioner is presented the annoyance and freshness as ${\alphs}$, ${\beta}$ exponents of 1/f slope and is changed the annoyance and freshness as exponents of 1/f slope are changed. The satisfaction index of an air-conditioner is not improved if SPL is above the proper level although the 1/f slope has optimal ${\alpha}$, ${\beta}$ values. Therefore, this paper proposes the satisfaction index of an air-conditioner considered both SPL and ${\alpha}$, ${\beta}$ exponents of 1/f slope.

• Nuclear Engineering and Technology
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• 제52권7호
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• pp.1503-1510
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• 2020

Ultra-low noise charge sensitive amplifiers (CSAs) based on various types of circuit board substrates, such as FR4, Teflon, and ceramics (Al₂O₃) with two different designs, PA1 and PA2, have been developed. They were tested to see the noise effect from the dielectric loss of the substrate capacitance before and after irradiation. If the electronic noise from the CSAs is to be minimized and the energy resolution enhanced, the shaping time has to be optimized for the detector, and a small feedback capacitance of the CSA is favorable for a better SNR. Teflon- and ceramic-based PA1 design CSAs showed better noise performance than the FR4-based one, but the Teflon-based PA1 design showed better sensitivity than ceramic based one at a low detector capacitance (<10 pF). In the PA2 design, the equivalent noise and the sensitivity were 0.52 keV FWHM for a silicon detector and 7.2 mV/fC, respectively, with 2 ㎲ peaking time and 0.1 pF detector capacitance. After 10, 100, 10³, 10⁴, and 10⁵ Gy irradiation the ENC and sensitivity characteristics of the developed CSAs based on three different substrate materials are also discussed.

• 감성과학
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• 제1권1호
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• pp.135-143
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• 1998

이 연구에서는 국제 사진 정서체계(International Affective Picture System: IAPS)중에서 가장 강한 부적 정서를 유발하는 6장의 슬라이드를 1분 동안 연속적으로 보여주어 스트레스 상태를 야기한 뒤 1분동안 정서를 유발하는 청각자극인 1/f음악이나 which noise를 들려주거나 또는 아무소리도 들려주지 않는 각 조건에서 뇌파의 상대적 출현량(reltive power)및 호흡률, 심박률, 피부전도수준 등의 자율신경계 반응의 변화를 분석하였다. 스트레스 정서 상태에서 이완상태로의 회복을 촉진시켜줌을 시사한다. 한편, 스트레스정서유발 상태에서 1/f 음악과 white noise이 제시되었을 때의 자율신경계 반응은 현저한 대비를 보여주었다. 그러나 스트레스 정서유발 이전의 기저선 수준과 비교할 때 1/f 음악에 의한 반응수준이 white noise 에 의한 반응수준 보다 기서선 수준에서 훨씬 더 벗어나 있었다. 따라서 이 결과는 부적정서상태에 부가된 정적 유발이 활성화된 자율신경계 반응의 안정상태로의 회복을 촉진한다는 가설을 지지하거나 부정하기에는 불충분하다. 이 연구에서 정서자극 제시 후의 회복단계에서 뇌파 반응과 자율신경계 반응의 시간경과에 따른 변화가 일치하지 않는 이유는 이들 생리신호의 반응속도가 다르기 때문일 수 있다. 이 실험은 시각과 청각의 복합 감각체계를 사용하여, 스트레스 정서상태에 정적정서유발자극이 부가되었을 때 스트레스 뇌파반응에서 이완된 뇌파반응으로의 회복이 촉진됨을 보여준 최초의 연구이다.

• 조명전기설비학회논문지
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• 제14권2호
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• pp.43-45
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• 2000

본 연구에서는 BICMOS 공정으로 제조된 바이폴라 프렌지스터의 SPICE 잡음 파라미터 추출방법을 제시하였다. 기하학적 분석요로부터 $K_f$ 값이 에미터 면적에 반비례하고 있음을 보였다. 그리고 $K=0.8\times10_{-20}, A_f=2, \alpha=1$ 값이 추출되었다.

• 화약ㆍ발파
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• 제20권4호
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• pp.5-15
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• 2002

발파, 항타와 같은 소원음이 존재하는 건설현장에서의 소음저감대책으로는, 소음원 또는 수음점에 방음벽을 설치하여 전파되는 소음을 차단하는 것이 가장 경제적인 경우가 대부분이다. 이러한 방음벽은 소음설계와 구조설계를 통해 그 규모가 결정되며, 방음벽의 구조적 안전을 보장하기 위해서는 KS F4770에 의한 방음판의 구조적 품질이 보장되어야 한다. 본 논문에서는 이 중 금속재 흡음형 방음벽 관련 규정인 F4770-1 - 2001을 분석하여, 그 문제점을 지적하고, 수정 또는 개선 사항을 제시하였다. 분석결과, 보다 경제적인 방음벽의 설치를 위하여 하중의 세분화와 함께 시험방법의 개선이 필요한 것으로 나타났다. 이와 함께 독일의 방음벽 설계시 사용되는 규정인 ZTV-Lsw 88과 비교, 검토하였으며, 검토 결과, 한국 규정은 독일규정에 비해, 보수적인 것으로 나타났다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.612-617
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• 2014

It is generally known that the automotive road wheel involves the non-proportional multiaxial loading condition, therefore the measuring dynamic stress and strain in driving state is very important to predict an endurance characteristic of the automotive road wheel. In this study, the ultimate driving test using F1 circuit with respect to 2 kinds of velocity conditions have been carried out in order to measure dynamic stress, strain of the wheel and acceleration of a vehicle. Based on the measured results, the characteristics of dynamic stress generation have been analyzed, and factors which have effect on the dynamic stress generation have been studied.

• Journal of applied mathematics & informatics
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• 제15권1_2호
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• pp.363-375
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• 2004

In this paper, We show that the bandpass random signals of the form ∑$_{\alpha}$$\alpha$$_{\alpha}$ a Sin(2$\pi$f$_{\alpha}$t + b$_{\alpha}$) where a$_{\alpha}$ being a random number in [0,1], f$_{\alpha}$ a random integer in a given frequency band, and b$_{\alpha}$ a random number in [0, 2$\pi$], generate Gaussian white noise signals and hence they are adequate for simulating Continuous Markov processes. We apply the result to the fluctuation-dissipation formula for the Johnson noise and show that the probability distribution for the long term average of the power of the Johnson noise is a X$^2$ distribution and that the relative error of the long term average is (equation omitted) where N is the number of blocks used in the average.error of the long term average is (equation omitted) where N is the number of blocks used in the average.

• Progress in Superconductivity
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• 제11권2호
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• pp.152-157
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• 2010

We have fabricated the low noise liquid helium(LHe) dewar with a different shape of thermal shield to apply the 64-channel SQUID(Superconducting Quantum Interference Device) gradiometer. The first shape of thermal shield was made of an aluminum plate with a wide width of 100 mm slit and the other shape was modified with a narrow width of 20 mm slit. The two types of dewars were estimated by comparing the thermal noise and the signal-to-noise ratio(SNR) of magnetocardiography(MCG) using the $1^{st}$ order SQUID gradiometer system cooled each dewar. The white noise was different as a point of the dewar. The noise was increased as close as the edge of dewar, and also increased at the thermal shield with the more wide width slit. The white noise of the dewar with thermal shield of 100 mm slit was 6.5 fT/$Hz^{1/2}$ at the center of dewar and 25 fT/$Hz^{1/2}$ at the edge, and the white noise of the other one was 3.5 - 7 fT/$Hz^{1/2}$. We measured the MCG using 64-channel SQUID gradiometer cooled at each LHe dewar and compared the SNR of MCG signal. The SNR was improved of 10 times at the LHe dewar with a modified thermal shield.

• 전자공학회논문지CI
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• 제39권1호
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• pp.75-81
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• 2002

In this paper, data rate of VDSL system was analyzed in noise and crosstalk environment. For this paper, Matlab tool was used to analyze the performance of VDSL system. Various "VDSL Test Loop" are used which is suggested by ANSI DSL Standard group T1E1.4. Many parameters, "Noise Model A", "Noise Model F", duplex method VDSL-998 which is suggested FDD plan by ANSI was used. The most of conditions for simulation are followed to the ANSI Standard "Spectrum management" Lots of data have been obtained according to the different conditions of the test loops. The result shows that the data rate of VDSL system is decreased due to the other DSL signals in the same cable bundle. And also there was more reduced data rate in case of Noise Model F than that of Noise Model A.