• Journal of Communications and Networks
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• 제16권3호
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• pp.301-304
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• 2014

This paper proposes accurate interference probability and bit error rate formulas for cognitive relay networks with underlay spectrum sharing and channel estimation error (CEE). Numerous results reveal that the CEE not only degrades the performance of secondary systems (SSs) but also increases interference power caused by SSs to primary systems (PSs), eventually unfavorable to both systems. A solution to further protect PSs from this effect through reducing the power of secondary transmitters is investigated and analyzed.

• 대한전자공학회논문지
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• 제6권1호
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• pp.1-11
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• 1969

TRIGA MARK-II 원자로의 각출력에 대한 주파수스펙트럼을 측정하므로서 원자로의 전달함수의 계수율을 선정하였다. 랜덤한 파일잡음의 검출은 전전력에서 10-7A인 평행원부형 전리함을 이용하였다. 주파수스펙트럼은 동조형대역통과 여파기를 가지고 해석하여 원자로의 동특성과 그 피라미터를 구하고 전력측정을 하였다.

• 천문학회지
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• 제37권5호
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• pp.349-353
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• 2004

Magnetic fields are an important ingredient of galaxy clusters and are indirectly observed on cluster scales as radio haloes and radio relics. One promising method to shed light on the properties of cluster wide magnetic fields is the analysis of Faraday rotation maps of extended extragalactic radio sources. We developed a Fourier analysis for such Faraday rotation maps in order to determine the magnetic power spectra of cluster fields. In an advanced step, here we apply a Bayesian maximum likelihood method to the RM map of the north lobe of Hydra A on the basis of our Fourier analysis and derive the power spectrum of the cluster magnetic field. For Hydra A, we measure a spectral index of -5/3 over at least one order of magnitude implying Kolmogorov type turbulence. We find a dominant scale of about 3 kpc on which the magnetic power is concentrated, since the magnetic autocorrelation length is ${\lambda}_B = 3 {\pm} 0.5\;kpc$. Furthermore, we investigate the influences of the assumption about the sampling volume (described by a window function) on the magnetic power spectrum. The central magnetic field strength was determined to be ${\~}7{\pm}2{\mu}G$ for the most likely geometries.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.502-507
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• 2008

An entire composite structure satellite is developing for the first time in Korea. All of the structure is made of CFRP-composite faced aluminum honeycomb sandwich structure. Here the random and sinusoidal spectrum analysis of the satellite was carried out by using the finite element method. The general spectrum analysis was herein performed but also the PSD (power spectrum density) function for random vibration analysis had been transformed into equivalent time domain function and then transient analysis is conducted. The time history of displacement, acceleration, stress and velocity responses with respect to the PSD input has been achieved by the time dependent transient function transformed from frequency PDS function. It enables one to perform dynamic durability analysis and then expect the life time of the composite structure. The composite faced sandwich structure's spectrum analysis of a domestically-developed satellite, STSAT-3, has been discussed in the present study.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.498-498
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• 2001

Seismic qualification of the Main Control Boards for nuclear power plants has been performed with the guideline of AS ME Section III. US NRC Reg. Guide and IEEE 344 code. The analysis model of the Main Control Boards is consist of beam. shell and mass element by using the finite element method. and, at the same time. the excitation forces and other operating loads for each model are encompassed with respect to different loading conditions. As the fundamental frequencies of the structure are found to be less than 33Hz. which is the upper frequency limit of the seismic load, the response spectrum analysis using ANSYS is performed in order to combine the modal stresses within the frequency limit. In order to confirm the structural and functional integrity of the major components, modal analysis theory is adopted to derive the required response spectrum at the component locations. As all the combined stresses obtained from the above procedures are less than allowable stresses and no mechanical or electrical failures are found from the seismic testing, it concludes the Main Control Boards is dynamically qualified for seismic conditions. Although the authors had confirmed the structural and functional integrity of both Main Control Boards and all the component, in this paper only the seismic analysis of the Main Control Board is introduced.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.3731-3750
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• 2014

This paper considers a wideband cognitive radio network (WCRN) which can simultaneously sense multiple narrowband channels and thus aggregate the detected available channels for transmission and studies the ergodic throughput of the WCRN that operated under: the wideband sensing-based spectrum sharing (WSSS) scheme and the wideband opportunistic spectrum access (WOSA) scheme. In our analysis, besides the average interference power constraint at PU, the average transmit power constraint of SU is also considered for the two schemes and a novel cognitive radio sensing frame that allows data transmission and spectrum sensing at the same time is utilized, and then the maximization throughput problem is solved by developing a gradient projection method. Finally, numerical simulations are presented to verify the performance of the two proposed schemes.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.755-762
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• 2004

In our country, when the replacement for individual components of equipment in nuclear power plants is required, establishment of individual criteria i.e. Required Response Spectra(RRS) of seismic test/analysis for the component is very difficult because of the absence of Test Response Spectra(TRS) for the individual component to be replaced, from the existing qualification documents. In this case, it is required to perform the structural analysis for the nuclear equipment including the components to be replaced. After the structural analysis, Analysis Response Spectra(ARS) at the point of the component shall be generated and used for seismic test of the component. However, as of today, no standard program authorized for the response spectra generation by using the structural analysis exists in korea. Because of above reason, the STAR-Egs computer program was developed by using the method which calculates directly the expected response spectrum(frequency vs. acceleration type) of the selected points in the nuclear equipment with input spectrum(Required Response Spectra, RRS), based on the dynamic characteristics of the Finite Element(FE) model that is equivalent to the nuclear equipment. The STAR-Egs controls ANSYS/I-DEAS commercial software and automatically extract modal parameters of the FE model. The STAR-Egs calculates response spectrum using the established algorithm based on the extracted modal parameters, too. Reliance on the calculation result of the STAR-Egs was verified through comparison output with the result of MATLAB commercial software based on the identical algorithm. Moreover, actual seismic testing was performed as per IEEE344-1987 for the purpose of program verification by comparison of the FE analysis results.

• Korean Journal of Acupuncture
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• 제28권3호
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• pp.85-98
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• 2011

Objectives : The aim of this thesis is to examine the effect of acupuncture treatment at the GB37 on normal humans by using the power spectral analysis of the EEG. Methods : EEG (Electroencephalogram) power spectrum exhibits site-specific and state-related differences in specific frequency bands. In this thesis, the power spectrum was measured by the complexity. the 32 channels EEG study was carried out in the 13 subjects (12 males ; age=22.58 years old, 1 females ; 22 years old). Results : In the ${\alpha}$ (alpha) band, the power values at F7, F3, F4, F8, FTC2, C4, T4, CP1, CP2, TCP2, TT2, Pz, P4, Po1, Po2, O1, Oz, O2 channels (p<0.05) during the GB37-acupoint treatment were significantly changed. And in many channels were decreased. In the ${\beta}$ (beta) band, the power values at Cz, C4, T4, Tcp1, T6, Po1, O1, Oz, O2 channels (p<0.05) during the GB37-acupoint treatment were significantly changed. And in many channels were decreased. In the ${\delta}$(delta) band, the power values at Fp1, TT2 channels (p<0.05) during the GB37-acupoint treatment were significantly changed. And in many channels were decreased. In the $\theta$ (theta) band, the power values at Fp1, F8, FTC2, Pz channels (p<0.05) during the GB37-acupoint treatment were significantly changed. And in many channels were decreased. Conclusions : This results suggest that the acupuncture treatment at the GB37 significantly mostly change the power spectrum value on the alpha (18 channels), beta (9 channels) bands.

• Journal of Biosystems Engineering
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• 제22권1호
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• pp.41-48
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• 1997

A nondestructive quality inspection technique using acoustic impulse response method was studied to investigate the feasibility of egg shell inspection. An experimental system was built to generate impact force, to measure the response signal and to analyze the frequency spectrum. This system includes an impulse generating unit, an egg holding seat, a microphone with preamplifier, and a digital oscilloscope connected to Personal Computer by RS-232C interface. The factors such as impulse generating method, egg holding method, and sensor location were evaluated by analyzing the power spectrum density of the measured signal. The results obtained are summarized as follows : 1. From the sampled eggs, the proper conditions for detecting damaged eggs were found as followings; ceramic for the impact ball material, rubber for egg seat material, 20 degrees for an impact angle of pendulum, 10mm for the distance between egg and sensor, the sharp side for impacting part, and 180 degrees for the location of sensor. 2. Examination of the Fourier transformed analysis in beth normal and damaged eggs revealed that those factors such as the resonant frequency, a number of peak frequencies and the magnitude of power spectrum were important to detect damaged eggs.

• Nuclear Engineering and Technology
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• 제41권1호
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• pp.113-124
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• 2009

The line shape functions for the Doppler-broadened gamma ray spectrum are considered in the $^{10}B(n,{\alpha}{\gamma})^7Li$ reaction occurring in a surrounding medium where the excited $^7Li$ nucleus is slowed down and stopped before decay. The phenomenological form of the stopping power was used for the broadening effect. Convolution with the detailed response of a germanium detector is taken into consideration for the simplest case of solely electronic stopping. A numerical study for the analysis of $^{10}B$ by thermal neutron capture is conducted by performing a parametric search and fitting the measured spectrum in a least-squares approach. In comparison with the previous numerical approach using the same analysis, the computational speed is increased and reliable information concerning the stopping power of the medium is obtained while estimating the uncertainty. Implementation of the routine analysis of $^{10}B$ is facilitated on a recent version of the gamma ray spectrum analysis package HyperGam.