• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.197-198
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• 1998

We tested the capability of Pointwise Correlation Dimension(PD2), Approximate Entropy (ApEn) and LZ complexity, as alternative measures of a biological signal. For this purpose, we analyzed standard data and a healthy child's 24-hour heart rate variability. Our conclusion is as follows. First, PD2, ApEn and LZ complexity can be used for discerning chaotic attractor, white noise, and periodic signal. Second, these measures show different characteristics on day and night. Third, these measures can be used for detecting time-varying characteristics of biological signals.

• Journal of the Korean Society of Clothing and Textiles
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• v.1 no.1
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• pp.7-13
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• 1977

The insulating values of 7 kinds of woman's Korean-styled clothes were examined on the instrumented copper mannequin standing upright under still air condition in a climatic chamber at $20^{\circ}C$ and $60\%$ R.H.. Results obtained are as follows: 1) High correlation coefficients were found in both between total insulating values of clothing (IT) and total clothing weight. and between IT and total clothing thickness while no significant difference was found between total clothing weight and total clothing thickness. 2) It seems possible to predict the approximate insulating value of woman's Korean styled clothes on still air condition by the total clothing weight.

• The Journal of the Acoustical Society of Korea
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• v.2 no.1
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• pp.48-58
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• 1983

The transient sound radiation from the impact between a steel ball and a thick plate is analyzed theoretically and compared with experiment results. The derivation process itself is difficult to analyze sound radiation characteristics theoretically for a thick plate with some resonances but may be investigated from measured data. During mechanical impacts, arbitrary driving point importance for an elastic system enables to predict by using mechanical importance method. In order to obtain approximate solution for an impact model testing, the surface Helmholtz integral formulation based on the integral expression for pressure in the field in terms of surface pressure and normal velocity is used as a basis. A simple expression is developed for an impulsive response function, which is time dependent velocity potential and pressure for an impact may then be computed by a convolution of exciting force. In estimating of elastic-acoustical correlation problems, mechanical inertance, overall transfer function and radiation resistance obtained by signal processing techniques are used. The usefulness is confirmed by applying these methods prediction of arbitray driving pint inertance, radiated sound pressure and exciting force.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1125-1132
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• 2005

Ultra-wideband (UWB) ranging poses a set of time delay estimation problems for designers. The possibility of a large error can be a challenging problem for accurate ranging and positioning. An approximate analysis of large error performance of UWB ranging in multipath and multiuser environments is posed. Both analytical and experimental approaches are taken to evaluate the large error variance in a correlation-based serial search scenario.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.134.1-134.1
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• 2012

The radiation belt structure can be approximately reproduced by a form of diffusion equation, which takes into account the radial diffusion process as well as those in pitch angle and energy. The solution of the equation depends on several factors including initial and boundary conditions, diffusion coefficients, and plasmapause location. In this paper, we have attempted to determine a set of approximate functions for the energetic electron fluxes near the outer edge of the outer belt in terms of solar wind variable. We used the electron flux data from SST onboard the THEMIS spacecraft and determined its correlation with solar wind conditions in a systematic way. The functions were determined separately for different energy channels from ~30 keV up to 719 keV. Our determination of these functions allows us to predict the radial boundary condition for the electron flux, which can be implemented in a forecast model.

• Journal of Information Processing Systems
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• v.6 no.4
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• pp.511-520
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• 2010

This paper proposes two new methods to detect the fingerprints of different persons based on one-dimensional and two-dimensional discrete wavelet transformations (DWTs). Recent literature shows that fingerprint detection based on DWT requires less memory space compared to pattern recognition and moment-based image recognition techniques. In this study four statistical parameters - cross correlation co-efficient, skewness, kurtosis and convolution of the approximate coefficient of one-dimensional DWTs are used to evaluate the two methods involving fingerprints of the same person and those of different persons. Within the contexts of all statistical parameters in detection of fingerprints, our second method shows better results than that of the first method.

• The Journal of Engineering Research
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• v.1 no.1
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• pp.31-40
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• 1997

We first describe an approximation method for fitting a k-state MMBP to the departure process of a D-BMAP/Geo/1/K queue. The fitting model is them used in a simple decomposition algorithm to analyze a tandem configuration of finite capacity queue with cell loss.

• Journal of the Korea Institute of Building Construction
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• v.22 no.3
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• pp.293-303
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• 2022

In construction work, it can be difficult to know the exact number of full-time workers, so the accident rate is calculated using the approximate number of full-time workers. In addition, as the accident rate calculation is performed based on the assumption that the number of accidents is proportional to the approximate number of workers, the reliability of the calculation result may be questionable. This study proposed a new indicator for accident level based on the progress payment and the number of injuries. The accident-progress ratio, which can be calculated by simply dividing the number of injuries by progress payment, can replace the existing accident rate index or be used as an auxiliary indicator of the accident level. The correlation coefficient between the number of injuries and the progress payment was higher than that between the number of injuries and the number of construction workers. In addition, over the past 10 years, the accident rate has been increasing, whereas the accident-progress ratio has showed a decreasing tendency. This might leave room for different interpretations of the annual variation in the accident level in the construction industry.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.243-247
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• 2007

Fuel mass flux was experienced with a function of the oxidizer mass flux using initial port area of solid fuel, in stead of regression rate correlation which shows combustion characteristic in hybrid propulsion. The burning rate could be easily obtained by using the oxidizer mass flux of initial port area without iteration, and fuel configuration could be designed simply. In this experiments PE was used as fuel, COX was used as oxidizer. A variation of mass flux of solid fuel with port area is considered by changing the burning time. In the case of approximate 0.5 for an exponent of oxidizer mass flux, using the fuel mass flux correlation is more suitable than regression rate correlation in hybrid propulsion.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.8-15
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• 2006

In this paper, we propose the iterative receiver for LDPC-coded OFDMA systems in uplink environments. Applying the Wiener filtering to pilot symbols, an initial channel estimation can be performed effectively. To reduce the complexity of the Wiener filtering, we approximate Wiener filtering coefficients to pre-determined coefficients according to estimated correlation of channel. After an LDPC decoding process, soft symbol derived by extrinsic information of decoder outputs is used to estimate channel. we also derive the error variance of channel estimation and maximum ratio combined results. Using combined results, the channel correlation is re-estimated. Then the proper Wiener filtering coefficients are chosen according to the re-estimated result of the channel correction. Using a computer simulation, we show that the proposed receiver structure has the better performance than the receiver using only pilot symbols.