• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4573-4584
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• 2015

The traditional feature extraction algorithms for recognition of communication signals can hardly realize the balance between computational complexity and signals' interclass gathered degrees. They can hardly achieve high recognition rate at low SNR conditions. To solve this problem, a novel feature extraction algorithm based on Holder coefficient was proposed, which has the advantages of low computational complexity and good interclass gathered degree even at low SNR conditions. In this research, the selection methods of parameters and distribution properties of the extracted features regarding Holder coefficient theory were firstly explored, and then interval gray relation algorithm with improved adaptive weight was adopted to verify the effectiveness of the extracted features. Compared with traditional algorithms, the proposed algorithm can more accurately recognize signals at low SNR conditions. Simulation results show that Holder coefficient based features are stable and have good interclass gathered degree, and interval gray relation classifier with adaptive weight can achieve the recognition rate up to 87% even at the SNR of -5dB.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.85-86
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• 2002

For rheology investigation of lubricating oils, first phase diagrams were made from determined free volume based on density measurements and the temperature-pressure relation was estimated using the expansion coefficient of free volume and the temperature-pressure relation of the viscoelastic transition point. Next, the authors proposed the density-pressure-temperature relation and the viscosity-pressure-temperature relation of the tested oils based on the free volume and the phase diagrams. Moreover, it was shown that the Ehrenfest equation or the gradient of the phase diagram is closely related to the expansion coefficient of free volume.

• Human Ecology Research
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• 제56권2호
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• pp.175-193
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• 2018

This study identified the rate of income poverty and multidimensional poverty, correlation between income poverty and multidimensional poverty, and adjusted multidimensional poverty rate. We also analyzed the factors that affected the number of poverty dimension and the probability of belonging to the poor or not in 3,159 elderly households including 474 poor households and 2,685 middle class households. First, in poor households, the employment poverty rate was the highest and the housing poverty rate was the lowest. In middle class households, the relation poverty rate was the highest and the employment poverty rate was the lowest. Second, in poor households, correlation between asset poverty and relation poverty had the highest coefficient of .205 and asset poverty and housing poverty had the lowest coefficient of .149. In middle class households, the correlation between income poverty and relation poverty had highest coefficient of -.290 and employment poverty and relation poverty had the lowest coefficient of .038. Third, in poor households, the number of average poverty dimension was 4.30, but the number of average poverty dimensions of middle class households was 2.310. Fourth, the variable affecting the number of poverty dimensions in poor households were gender, age, level of education, marital status; however, the significant variables were gender, education level, marital status, income poverty in the middle class households. The variable that affected the probability of belonging to the poor or not in poor households was age. However, the significant variables were gender, education level, marital status, residence, and income poverty in middle class households.

• 조명전기설비학회논문지
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• 제18권1호
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• pp.73-77
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• 2004

전력 시스템의 오손에 의한 사고 방지를 위한 가장 효과적인 방법은 오손도를 정확하게 예측하는 것이다. 전력시스템은 옥외에 노출되어 있으므로 오손 및 열화가 불가피하며, 오손의 증가는 사고의 위험성을 악화시킨다. 한편, 오손의 주요소는 염분이며, 오손도는 등가 염분 부착 밀도(ESDD)로서 나타낼 수 있다. 기후 조건은 지속적으로 오손도를 증감시키고 있다. 기후와 오손도의 상관관계를 해석하여 오손도를 예측할 수 있으며, 다중 회귀 분석방법를 통하여 분석이 가능하다. 이와 관련된 선행연구에서는 높은 신뢰도를 확인할 수 있었다(0.874). 그러나 이러한 방법은 다른 시기에 적용한 경우 상관성이 상당히 하강하였다. 본 연구는 이와 같은 신뢰도를 더욱 향상 시키고(0.898), 정밀한 오손도 예측을 위한 통계처리를 수행하였다.

• 천문학회보
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• 제35권1호
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• pp.79-79
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• 2010

To investigate whether the present-day active galaxies follow the same black hole mass vs. stellar velocity dispersion (MBH-$\sigma*$) relation as quiescent galaxies, we measured the velocity dispersions of a sample of local Seyfert 1 galaxies, for which black hole masses were measured via reverberation mapping. We measured stellar velocity dispersions from high S/N optical spectra centered on the Ca II triplet region (${\sim}8500^{\circ}A$), obtained at the Keck, Palomar, and Lick Observatories. For two objects, in which the Ca II triplet region was contaminated by nuclear emission, we used high-quality H-band spectra obtained with the OH-Suppressing Infrared Imaging Spectrograph and laser-guide star adaptive optics at the Keck-II Telescope. Combining our new measurements with data from the literature, we assemble a sample of 24 active galaxies with stellar velocity dispersions and reverberation MBH in the range of black hole mass 106< MBH /$M{\odot}$ < 109,toobtainthefirstreverberationmappingconstraintsontheslopeandintrinsicscatteroftheMBH- $\sigma*$ relation of active galaxies. Assuming a constant virial coefficient f for the reverberation MBH, we find a slope ${\beta}=3.55{\pm}0.60$ and the intrinsic scatter ${\sigma}int=0.43{\pm}0.08$ dex in the relation log (MBH/M${\odot}$)=$\alpha+\beta$ log(${\sigma}*$/200 km s-1), which are consistent with those found for quiescent galaxies. We derive an updated value of the virial coefficient f by finding the value which places the reverberation masses in best agreement with the MBH - $\sigma*$ relation of quiescent galaxies; using the quiescent MBH - $\sigma*$ relation determined by Gultekin et al. we find log f=0.72+0.09 (or $0.71{\pm}0.10$) with an intrinsic scatter of $0.44{\pm}0.07$ (or 0.46+0.07) dex. No correlations between f and parameters connected to the physics of accretion (such as the Eddington ratio or line-shape measurements) are found. The uncertainty of the virial coefficient remains one of the main sources of the uncertainty in black hole mass determination using reverberation mapping, and therefore also in single-epoch spectroscopic estimates of black hole masses in active galaxies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.4934-4949
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• 2015

The unstable characteristic values of communication signals along with the varying SNR (Signal Noise Ratio) environment make it difficult to identify the modulations of signals. Most of relevant literature revolves around signal recognition under stable SNR, and not applicable for signal recognition at varying SNR. To solve the problem, this research developed a novel communication signal recognition algorithm based on Holder coefficient and cloud theory. In this algorithm, the two-dimensional (2D) Holder coefficient characteristics of communication signals were firstly calculated, and then according to the distribution characteristics of Holder coefficient under varying SNR environment, the digital characteristics of cloud model such as expectation, entropy, and hyper entropy are calculated to constitute the three-dimensional (3D) digital cloud characteristics of Holder coefficient value, which aims to improve the recognition rate of the communication signals. Compared with traditional algorithms, the developed algorithm can describe the signals' features more accurately under varying SNR environment. The results from the numerical simulation show that the developed 3D feature extraction algorithm based on Holder coefficient cloud features performs better anti-noise ability, and the classifier based on interval gray relation theory can achieve a recognition rate up to 84.0%, even when the SNR varies from -17dB to -12dB.

• 한국정밀공학회지
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• 제27권8호
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• pp.7-12
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• 2010

When a vehicle is running, wheel is generating vertical and lateral force on the rail, in addition to load of vehicle, through a complicated set of motions. The derailment coefficient refers to the ratio of lateral force to vertical force(wheel load), and if the value exceeds a certain level, a wheel climbs or jumps over the rail. That's why the value is used as a criterion for running safety. Derailment coefficient of rolling stocks alters according to shape of rail track. I measured three-dimensional angular velocity and acceleration to use 3D Motion Tracker. Test result, derailment coefficient of rolling stocks and shape of rail track examined closely that have fixed relation. Specially, was proved that roll motion has the close coupling relation.

• 한국지구과학회지
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• 제38권5호
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• pp.333-344
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• 2017

We present the environmental dependence of the luminosity-size relation of galaxies in the local universe (z < 0.01) along with their dependence on galaxy morphology represented by five broad types (E, dEs, S0, Sp, and Irr). The environmental parameters we consider are the local background density and the group/cluster membership together with the clustercenteric distance for the Virgo cluster galaxies. We derive the regression coefficient (${\beta}$), i.e., the slope of the line representing the least-squares fitting to the data and the Pearson correlation coefficient (c.c.) representing the goodness of the least-squares fit along with the confidence interval from bootstrap resampling. We find no significant dependence of the luminosity-size relation on galaxy morphology. However, there is a weak dependence of the luminosity-size relations on the environment of galaxies, in the sense that galaxies in the low density environment have shallower slopes than galaxies in the high density regions except for elliptical galaxies that show an opposite trend.

• 한국세라믹학회지
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• 제40권10호
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• pp.921-924
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• 2003

A current-voltage relation for Positive Temperature Coefficient of Resistance (PTCR) ceramic was derived and compared with the experimental data. The new current-voltage relation was developed based on Heywangs double Schottky barrier model and a bias distribution across the grain boundary. The voltage limitation V < 4${\Phi}$$\sub$b/ suggested by Heywang is no longer necessary in the new expression for the voltage dependence of the resistance. The pulsed voltages were applied to the PTCR ceramic specimen in order to avoid possible temperature variation during the measurement.

• 대한수학회보
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• 제46권6호
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• pp.1061-1068
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• 2009

The intimate relation between the 3-j coefficient in Quantum Theory of Angular Momentum (QTAM) and the $_3F_2(1)$ hypergeometric series is exploited to derive new summation theorems, from formulas for the 3-j coefficient.