• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.1
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• pp.38-42
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• 2006

We report 1/f noise PSD(Power Spectrum Density) of sub-100 nm MOSFETs as a function of various parameters such as HCS (Hot Carrier Stress), bias condition, temperature, device size and types of MOSFETs. The noise spectra of sub-100 nm devices showed Lorentzian-like noise spectra. We could check roughly the position of a dominant noise source by changing $V_{DS}$. With increasing measurement temperature, the 1/f noise PSD of 50 nm PMOS device decreases, but there is no decrease in the noise of NMOS device. RTN (Random Telegraph Noise) was measured from the device that shows clearly a Lorentzian-like noise spectrum in 1/f noise spectrum.

• Proceedings of the KSRS Conference
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• v.1
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• pp.344-347
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• 2006

China Coastal Water (CCW) usually appears in the seas surrounding Jeju Island annually (June?October) and is very pronounced in August. The power spectrum density (PSD), sea level anomalies (SLAs), and sea surface temperatures (SSTs) were found to peak annually and semiannually. The peaks at intervals of 80-, 60-, and 43-days are considered to be influenced by CCW and the Kuroshio Current. Generally, low-salinity water appears to the west of Jeju Island from June through October and gradually propagates to the east, where CCW meets the Tsushima Current. Empirical orthogonal function (EOF) analysis of SLAs and SSTs indicated that the variance in SLAs and SSTs was 55.70 and 98.09% in the first mode, respectively. The PSD for the first mode of EOF analysis of SLAs was stronger in the western than in the eastern waters because of the influence of CCW. The PSD for the EOF analysis of SSTs was similar in all areas (the Yangtze Estuary and the waters to the west and east of Jeju Island), with a period of approximately 260 days.

• Journal of Digital Contents Society
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• v.5 no.4
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• pp.306-310
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• 2004

In this paper, we proposed a capacity enhancement method using TCM-128QAM modulation and bandwidth extension of 25MHz in HDR-WPAN (high data rate wireless personal area network) system. In case using TCM-128 QAM modulation scheme, we can obtain maximum 66Mbps transmission rate in bandwidth of 15MHz. If extend bandwidth by 25MHz and roll-off coefficient ${\alpha}=0.35$, we can obtain maximum 110Mbps transmission rate. These results are confirmed through PSD(power spectrum density) analysis and BER (bit error rate) performance.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.19-26
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• 2010

In this paper, we studied about the Embedded System of the biosignal measurement and analysis to sensibility evaluation in daily life for non-intrusive. This system is two kinds of measuring biosiganls(Electrocardiogram:ECG, Photoplethysmography:PPG) and analyzed by real-time wireless transmission to notebook PC using bluetooth for consistent and reliability of physiological way to assess continuously changing sensibility. Comparative studied of an autonomic nerve system activity ratio on characteristics frequency band of two kinds of biosignal analyzed frequency way using the Fast Fourier Transform(FFT) and Power Spectrum Density(PSD). Also the key idea of this system is to minimize computing of analysis algorithm for faster and more accurate to assess the sensibility, and the result of the visualization using graph. In this paper, we evaluated the analysis system to assess sensibility that measuring various situation in daily life using a non-intrusive biosignal measurement system, and the accuracy and reliability in comparison with difference of result by development analysis system.

• Journal of Korea Multimedia Society
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• v.22 no.11
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• pp.1233-1241
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• 2019

The goal of the sound-based mechanical fault diagnosis technique is to automatically find abnormal signals in the machine using acoustic emission. Conventional methods of using mathematical models have been found to be inaccurate due to the complexity of industrial mechanical systems and the existence of nonlinear factors such as noise. Therefore, any fault diagnosis issue can be treated as a pattern recognition problem. We propose an automatic fault diagnosis method using discrete wavelet transform and power spectrum density using multi pattern recognition. First, we perform DWT-based filtering analysis for noise cancelling and effective feature extraction. Next, the power spectral density(PSD) is performed on each subband of the DWT in order to effectively extract feature vectors of sound. Finally, each PSD data is extracted with the features of the classifier using multi pattern recognition. The results show that the proposed method can not only be used effectively to detect faults as well as apply to various automatic diagnosis system based on sound.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.6
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• pp.813-820
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• 2010

The spread mooring system for FPSO is developed to explore deep sea area, in which swell is dominant. It is known that the tension response of mooring lines in this sea area shows bimodal spectrum. Assuming normal distribution of tension profile and Rayleigh distribution of tension amplitude, the power spectral density function (PSD) of the mooring tension under the bimodal stationary random process is applied for the calculation of spectrum fatigue. Three popular methods, which are simple summation method, combined spectrum method and Jioa-Moan method, are used to combine fatigue damages from bimodal spectrum characteristics. Each damage value is compared with damage using Rainflow Cycle Counting (RCC) method which is believed to be close to exact solution. Vanmarcke' parameter and RMS(Root Mean Square) ratio are employed to assess relative damage variations between from RCC method and from three combination methods. Finally the most reliable fatigue damage combining method for spread mooring system is suggested.

• Corrosion Science and Technology
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• v.2 no.1
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• pp.18-25
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• 2003

Effects of the precipitation of $\sigma$ phase on the metastable pitting as a precursor of stable pitting corrosion and also on the progress of stale pitting of the 25Cr-7Ni-3Mo-0.25N duplex stainless steel were investigated in chloride solution. Electrochemical potential and current noises of the alloy were measured in 10 % ferric chloride solution ($FeCl_3$) with zero resistance ammeter (ZRA), and then analyzed by power spectral density (PSD) and by corrosion admittance ($A_c$) spectrum. With aging at $850^{\circ}C$, the passive film of the alloy was found to get significantly unstable as represented by power spectral density (PSD) and a transition from metastable pitting state to stable one was observed. In the corrosion admittance spectrum, the number of negative $A_c$ corresponding to the state of localized corrosion increased with aging, suggesting that the precipitation of $\sigma$ phase considerably degraded the passive film by depleting Cr and Mo around it at $\alpha/\sigma$ or $\gamma/\sigma$ phase boundaries, thereby leading to the initiation of the pitting corrosion. However, the Cr and Mo at $\alpha/\sigma$ or $\gamma/\sigma$ phase boundaries which were once depleted due to the precipitation of the $\sigma$ phase were partly replenished by the diffusion of Cr and Mo from the surrounding matrix with aging time longer. The initiation of pitting seems to be associated with the precipitation density of the $\sigma$ phase with an effective size needed to induce the sufficient depletion of Cr and Mo around it.

• Journal of Biomedical Engineering Research
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• v.30 no.4
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• pp.327-332
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• 2009

In this paper, new index was developed to estimate the depth of anesthesia during general anesthesia using EEG. Analysis of the power spectral density(PSD) of EEG was used to develop new parameters because EEG signal tends to have slow wave during anesthesia. Classifier for index creator was developed by using SEF, BDR and BTR parameters, which are calculated by power spectral density. EEG data were obtained from 7 patients (ASA I, II) during general anesthesia with Sevoflurane. The anesthetic depth evaluation indexes ranged from 0 to 100. The average were $86.05{\pm}10.1$, $36.98{\pm}20.2$, $15.33{\pm}13.6$, $50.87{\pm}16.5$ and $87.72{\pm}11.7$ for the states of pre-operation, induction of anesthesia, operation, awaked and post-operation, respectively. The results show that while the depth of anesthesia was evaluated, more accurate information can be provided for anesthetician.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.164-175
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• 1997

In this paper, the CE-OQPSK that has constant envelope was designed for applying PSK to the nonlinear amplifier so as to improve power efficiency. For this realization. ROM and D/A converter that have relative low power consumption were used. As a result of comparing the PSD (Power spectrum density) of CE-OQPSK with that of conventional OQPSK through simulation for estimating the performance. In case of correlation factor ${\alpha}$ = 0.707. the improvement of bandwidth efficiency of 5% and 20% is achieved in the main lobe and the sidelobe, respectively. And, in case additional bandwidth-limiting-filter is added, it can be shown that the PSD of CE-OQPSK meet the FCC wireless LAN spectrum specification.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.359-362
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• 2012

The results are shown highly unstable mode's detonation dynamics by compared with weakly unstable mode. And we investigate the difference and similar features of 2D and 3D results. By using PSD via FFT, the effects of pre-exponential factor difference and of unstable mode were investigated in this study. The result of PSD is shown pulsed features in weakly unstable mode, but noselike in highly unstable mode. By compared between Sheliren image and overlaid slice image, the irregular feature of detonation waves structure was discussed in highly unstable mode.