• Communications for Statistical Applications and Methods
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• v.9 no.1
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• pp.241-248
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• 2002

The problem of wavelet density estimation based on Shannon's wavelets is studied when the sample observations are contaminated with random noise. In this paper we will discuss the asymptotic normality for deconvolving wavelet density estimator of the unknown density f(x) when courier transform of random noise has polynomial descent.

• Progress in Superconductivity
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• v.9 no.1
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• pp.45-49
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• 2007

We have investigated the optimum combination of the environmental noise condition and type of SQUID pickup coil in order to obtain maximum signal-to-noise ratio (SNR). The measurement probe consists of 1st order gradiometer with pickup coils of 100 mm, 70 mm, and 50 mm baseline length, a 2nd order gradiometer with 50 mm baseline, and a magnetometer. The pickup coils are fabricated by winding Nb wire on a bobbin with 200 mm diameter. Noise and heart signal of a healthy male were measured by various SQUID sensors with different types of pickup coils in various magnetically shielded rooms (MSR), and compared to each other. The shielding factors were found to be 43 dB, 35 dB and 25 dB at 0.1 Hz for MSR-AS, MSR-BS, MSR-CS, respectively. White noises were $3.5\;fT/Hz^{1/2}$, $4.5\;fT/Hz^{1/2}$ and $3\;fT/Hz^{1/2}$ for the 1st order gradiometers, the 2nd order gradiometers, and magnetometer for all MSRs. SNR of the magnetometer was up to 56 dB in MSR-AS, while the 1st order axial gradiometer with 70 mm baseline length was up to 54 dB in MSR-BS. The 2nd order axial gradiometer with 50 mm baseline length of pickup coil was found to be up to 40 dB in MSR-CS.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.6
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• pp.655-661
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• 2013

In this paper, the 1/f noise characteristics of n-channel MOSFET (NMOSFET) and p-channel MOSFET (PMOSFET) are analyzed in depth as a function of body bias. The normalized drain current noise, $S_{ID}/I_D{^2}$ showed strong dependence on the body bias in the sub-threshold region for both NMOSFET and PMOSFET, and NMOSFET showed stronger dependence than PMOSFET on the body bias. On the contrary, both of NMOSFET and PMOSFET do not exhibit the dependence of $S_{ID}/I_D{^2}$ on body bias in strong inversion region, although the noise mechanisms of two MOSFETs are different from each other.

• The Journal of the Acoustical Society of Korea
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• v.10 no.3
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• pp.72-82
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• 1991

The Magnetic noise generated in three phase induction motor are investigated. Total noises measured by using JEM-1313 code and sound length method and the experimental formulae are derived of magnetic fk={K+$\frac{Z_s}{P}$(1-S)}f[Hz] noise is measured in the stator of induction motor except rotor supplied from power source and their datum are analyzed and compared with one another. The experimental value of magnetic noises are equal to the theoretical value at 1440[Hz] and 1560[Hz]. The biggest magnetic harmonic is generated at 1560[Hz].

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.376-382
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• 2001

최근 국내에서는 국제규격과의 부합화에 부응하여 바닥충격음에 대한 측정방법이 개정(2001년 6월 19일자 기술표준원 고시 제2001-334호)되어, KS F 2810-1(바닥충격음 차단성능 현장 측정방법 제1부- 표준 중량충격원에 의한 방법)과 KS F 2810-2(바닥충격음 차단성능 현장 측정방법 제2부 - 표준 중량충격원에 의한 방법)으로 규격화되었다. 이는 현장 측정방법으로서 완성된 건축물에 대한 차음성능을 공간성능으로 측정하고자 한 것이다. (중략)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.270-274
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• 2003

네트워크상태의 탄소나노튜브 나노선과 바나듐 옥사이드 나노선의 전압-전류 특성을 측정하고 옴성 전압전류특성과 함께 정류 다이오드 특성을 관측하였다 정류특성을 Schottky diode 관점에서 분석하였고 나노선을 이용한 다이오드의 이상지수가 10을 초과하는 큰 값을 가짐을 알았다. 2단자 전극상태에서 전류잡음 1/f 잡음형태가 관측되었다.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.387-390
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• 1998

In this paper, HBT's with lower phase noise and passive elements, such as resistors, capacitors and inductors, for resonance and impedance matching networks are designed, fabricated, tested, and carefully analysed, respectively, and then, they are integrated for the design and fabrication of functional X-band oscillators with lower phase noise. Epi-wafers for HBT's with the structure of graded $Al_{x}$G $a_{1-x}$ As emitter and C-doped base layer of 700.angs. thick were used to specially emphasize the improvement of $f_{T}$ and $f_{max}$, and the lowering of phase noise, in design aspects. At the test frequencies of 12GHz, capacitances of MIM capacitors, spiral inductor, and resistances are 0.5~10pF, 0.4~11.06nH, and 20~1,380.ohm., respectively. The emitter size of HBY's for the X-band MMIC oscillators is 3*10u $m^{2}$, and find chip size is 0.9*0.9m $m^{2}$..EX>.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.9
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• pp.972-981
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• 1992

In this paper, the performance of linear and hard-limiting correlation receivers for DS/SSMA BPSK power line communication system is analyzed. Strong impulsive noise of power line is modeled with Chan's noise model, and the performance of both receivers is analyzed in terms of parameters such as ratio of power spectrum density of impulsive noise to that background noise, ratio in impulsive noise width th that of data bit, and interarrival time of impulsive noise. And also multiple access capacity is evaluated with Gaussian approximation of multiple access interference. The results of this analysis reveal that the performance of linear correlation receiver is superior to that of hard-limiting correlation receiver when $N_1/N_b$ is small and is close to 1. But the BER and the multiple access capacity of hard-limiting correlation receiver becomes better in comparison with linear correlation receiver as $N_1/N_b$ increases.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.359-367
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• 2008

The maximum sound pressure level in a ship is restricted by the international standard such as MIL-Std. 740-1 in order to protect hearing ability for the crew on a ship. Especially, the noise of a fan system is restricted by the maximum level of the sound power according to the military specification such as MIL-F-1900A. In this paper, the reduction of tonal noise for the fan-motor system on a ship is described related to the electrical as well as structural problems. For the electrical problems, the difference of the magnetic flux caused by the variation of the air-gap is described related to the bad concentricity of the motor housing and the shaft-bearing. And for the structural problem, the resonance of the fan motor system is described.

• Journal of Acupuncture Research
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• v.23 no.3
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• pp.47-56
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• 2006

Methods : 40 of Female rats were allowed to mate with 40 of male rats. Then, female rats were delivered of offspring rats, After birth 28 days, offspring rats were divided 8 groups, The normal group(Group A), the 10 mg/kg Angelicae gig antis radix~treated group(Group B), the 50 mg/kg Angelicae gigantis radix-treated group(Group C), the 100 mg/kg Angelicae gig antis radix-treated group(Group D), The control (noise-treated) group(Group E). the noise -10 mg/kg Angelicae gigantis radix-treated group(Group F), the noise-50 mg/kg Angelicae gigantis radix~treated group(Group G), and the noise-100 mg/kg Angelicae gigantis radix-treated group(Group H)(n = 5 in each group), From the 15th day of pregnancy, all rats were subcutaneously injected with 50 mg/kg BrdU once a day 30 min before the starting of experimental treatment. Rats of the prenatal noise-treated group were applied with 95 decibel supersonic machine sound for 1h once a day until delivery, After birth 28 days, offspring rats intraperitoneally injected with 50 mg/kg of BrdU and offspring rats were treated Angelicae gigantis radix Herb-acupunture on chungwan(CV12) for 7 consecutive days. For the detection of BrdU-positive cells and Ki-67 positive cells in hippocampus, immunohistochemistry was performed. Results : 1. The number of BrdU-positive cells in the dentate gyrus of noise-treated group was significantly decreased to normal group, and the Group F, G, H were significantly increased to control group. 2. The number of Ki-67 positive cells in the dentate gyrus of noise-treated group was significantly decreased to control group, and the Group G, H were significantly increased to control group. Conclusion : We concluded that postnatal Angelicae gigantis radix administration has effect on cell proliferation in offspring rats with prenatal noise stress during pregnancy.