• Speech Sciences
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• v.14 no.2
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• pp.127-135
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• 2007

Feature vectors of speech are generally extracted from whole frequency domain. The inherent character of a speaker is located in the low band or high band frequency. However, if the speech is corrupted by narrowband noise with concentrated energy, speaker verification performance is reduced as the individual characteristic is removed. In this paper, we propose a PCA Covariance Model based on the multiband to extract the robust feature vectors against the narrowband noise. First, we divide the overall frequency band into several subbands. Second, the correlation of feature vectors extracted independently from each subband is removed by PCA. The distance obtained from each subband has different distribution. To normalize against the different distribution, we moved the value into the normalized distribution through the mapping function. Finally, the represented value applying the weighting function is used for speaker verification. In the experiments, the proposed method shows better performance of the speaker verification and reduces the computation.

• Journal of the Korean Society of Food Culture
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• v.14 no.4
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• pp.271-287
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• 1999

A change in distribution structure affect a consumption structure which may result in considerable changes in lifestyle including food purchase. The purpose of this study was to investigate the effect of change of distribution structure on the indigenous fermented food purchase. The informations of this study were obtained from 407 housewives residing in Seoul and the capital area by using questionnaire during May to June, 1997 Their data were statistically analyzed based on frequency, mean, and $X^2-test$. The results were as follows; 1) The percentages of subjects buying ready made fermented food were 69.8% for Jotkals(salt-fermented fish products), 22.3% for Kochujang(fermented red pepper soybean paste), 21.6% for Janachis(pickled basic side dishes), 21% for Kanjang(Korean style soybean sauce), 17.1% for Toenjang(Korean style soybean paste), and 3% for Kimchi(seasoned and fermented vegetables). 2) With decreasing age, preparation ability of Kanjang, Janachis, and Kimchi. The subjects living close to the new distribution channel were higher in ready made fermented food than the others. 3) Compared to the subject living far from the new distribution channel, the subject living close to the new distribution channel was high in frequency of new distribution channel utilization for indigenous fermented food purchase but low in frequency of conventional market utilization. The younger in age, higher in educational level, and nuclear family, the higher the utilization of new distribution channel for indigenous fermented food purchase.

• Journal of the Korean Society for Nondestructive Testing
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• v.19 no.4
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• pp.270-276
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• 1999

Fourier transform has been one of the most commonly used tools in study of frequency characteristics of signal. However, based on the Fourier transform. it is hard to tell whether a signal's frequency contents evolve in time or not. Recently, to overcome Fourier transform fault. not to represent non-stationary signal, time-frequency analysis methods are developed and those can represent informations of signal's time and frequency at the same time. In this study we analysed ultrasonic signal for degraded SUS 316 with time-frequency analysis method. In particular the methods such as short time Fourier(STFT) and Wigner-Ville distribution(WVD) were used to extract frequency contents and characteristics from ultrasonic signals.

• Journal of Ginseng Research
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• v.4 no.1
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• pp.49-54
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• 1980

This investigation were carrion out to know the frequency, size and distribution of stomata in Korean ginseng, acanthopanax and codonopsis. The results are as follows; 1. Stomatal frequency in ginseng leaf was remarkably less than those of acanthopanax and codonopsis leaf, but size of stomata in ginseng leaf was larger than those of acanthopanax and codonopsis leaf. 2. Stomatal frequency of one year old ginseng plant was higher than those of the older. Two to five years old ginseng plants were not differed in frequency and size of stomata. 3. Frequency and size of stomata were higher and larger in red-berry variant in compare to yellow-berry variant. 4. Stomatal frequency in different leaf Position was not significantly different among those of middle leaf, first side leaf and second side leaf, but in decreasing order of middle Part, upper, lower part and edge in the same ginseng leaf. 5. Stomata was not seen in adaxial surface and petiole of leaf ginseng, acanthopanax and codonopsis. 6. Stomatal frequency was higher in ginseng plant grown under no$.$shading compared to shading, and that of ginseng plant in rear line was less than that of front line under the same shade roof.

• Water for future
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• v.28 no.2
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• pp.145-154
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• 1995

The various analyses of the historical rainfall data need to be utilized in a hydraulic engineering project. The probability distributions of the rainfall events according to annual maximum continuous rainfall depths are studied for the hydrologic frequency analysis. The bivariate normal distribution, the bivariate lognormal distribution, and the bivariate gamma distribution are applied to the rainfall events composed of rainfall depths and its durations at Kangnung, Seoul, Incheon, Chupungnyung, Teagu, Jeonju, Kwangju, and Busan. These rainfall events are fitted to the the bivariate normal distribution and the bivariate lognormal distribution, but not fitted to the bivariate gamma distribution. Frequency curves of probability rainfall events are suggested from the probability distribution selected by the goodness-of-fit test.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.3
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• pp.43-52
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• 1992

Design low flows were derived from the decision of a best fitting probability distribution and of an optimum transformation method can be contributed to the planning of water utilization and management of various hydraulic structures during dry season in the main river systems in Korea. The results were analyzed and summarized as follows. 1.Basic statistics for the selected watersheds were calculated as one of means for the analysis of extremal distribution. 2.Parameters for the different frequency distributions were calculated by the method of moment. 3.Type m extremal distribution was confirmed as a best one among others for the frequency distribution of the low flows by x$^2$ goodness of fit test. 4.Formulas for the design low flows of the Type m extremal distribution with two and three parameters were dervied for the selected watersheds. 5.Design low flows for the Type m extremal distribution when a minimum drought is zero or larger than zero were derived for the selected watersheds, respectively. 6.Design low flows of the Type m extremal distribution with two parameters are appeared to be reasonable when a minimum drought approaches to zero and the observed low flows varied within a relating small range while those with three parameters are seemed to be consistent with the probability distribution of low flows when a minimum drought is larger than zero and the observed low flows showed a wide range.

• Smart Structures and Systems
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• v.19 no.3
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• pp.309-322
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• 2017

In this paper, the buckling, and free vibration analysis of tapered functionally graded carbon nanotube reinforced composite (FG-CNTRC) micro Reddy beam under longitudinal magnetic field using finite element method (FEM) is investigated. It is noted that the material properties of matrix is considered as Poly methyl methacrylate (PMMA). Using Hamilton's principle, the governing equations of motion are derived by applying a modified strain gradient theory and the rule of mixture approach for micro-composite beam. Micro-composite beam are subjected to longitudinal magnetic field. Then, using the FEM, the critical buckling load, and natural frequency of micro-composite Reddy beam is solved. Also, the influences of various parameters including ${\alpha}$ and ${\beta}$ (the constant coefficients to control the thickness), three material length scale parameters, aspect ratio, different boundary conditions, and various distributions of CNT such as uniform distribution (UD), unsymmetrical functionally graded distribution of CNT (USFG) and symmetrically linear distribution of CNT (SFG) on the critical buckling load and non-dimensional natural frequency are obtained. It can be seen that the non-dimensional natural frequency and critical buckling load decreases with increasing of ${\beta}$ for UD, USFG and SFG micro-composite beam and vice versa for ${\alpha}$. Also, it is shown that at the specified value of ${\alpha}$ and ${\beta}$, the dimensionless natural frequency and critical buckling load for SGT beam is more than for the other state. Moreover, it can be observed from the results that employing magnetic field in longitudinal direction of the micro-composite beam increases the natural frequency and critical buckling load. On the other hands, by increasing the imposed magnetic field significantly increases the stability of the system that can behave as an actuator.

• Korean Journal of Community Nutrition
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• v.26 no.4
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• pp.296-306
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• 2021

Objectives: The objective of this study was to estimate the distribution of the usual dietary intake of foods with respect to the probability of consumption derived from the Food Frequency Questionnaire (FFQ) of the 2009 Korea National Health and Nutrition Examination Survey (KNHANES). Methods: The intake quantity and frequency of 63 food items were assessed from the 2009 KNHANES which was completed by 7,708 participants. The participants completed one or two 24-h dietary recalls and one FFQ. The usual intake distribution was estimated using the multiple source method (MSM), and the proportion of non-consumers was calculated through the usual intake distribution. This was then compared with the proportion of non-consumers from the 24-hour recall method. Results: The difference in the proportion of non-consumers ranged from 2% to 82.9%, indicating that there is a very large difference based on food groups. The food groups in which the proportion of non-consumers did not differ was composed of foods consumed daily, such as 'rice', 'cereal and barley', and 'Chinese cabbage and kimchi', or foods with distinct palatability such as 'coffee' and 'alcohol'. On the other hand, in the case of the food groups with a high difference in the proportion of non-consumers, most comprised fruits that emphasized seasonality. Conclusions: In the case of foods or food groups that are occasionally consumed, it is desirable to use 2 recalls with additional FFQ data by combining the consumption frequency and the quantity consumed.

• Journal of Korea Water Resources Association
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• v.40 no.8
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• pp.643-654
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• 2007

This study proposes and evaluates a methodology for deriving the rainfall intensity- duration-frequency relationship for durations less than 10 minutes used for designing drainage systems in small urban catchments and roads. The method proposed in this study is based on the Moupfouma distribution, which has been evaluated by applying it to the rainfall data at the meteorological Seoul station. Summarizing the results is as follows: (1) The frequency analysis results using minutely rainfall data was found not to be corresponded with the extrapolation of that by the Ministry of Construction and Transportation (2000). (2) The annual maxima minutely rainfall data derived by applying the Moupfouma distribution to the accumulated 60-minute data was found to well reproduce the characteristics of those of observed. (3) The rainfall intensity-duration-frequency relationship derived by applying the Moufouma distribution to the accumulated 50-minute data and hourly data was found insignificant.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.310-312
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• 2004

The aim of this study was to analyze the characteristics of knee joint sound in frequency domain and classify the knee joint diseases. The spectral analysis of knee joint sounds was performed using LPC(Linear Predictive Coding) and Wigner-Ville distribution. Ten normal subjects and 5 patients with meniscal tearing were enrolled. Each subject was seated on a chair and underwent active knee flexion and extension for 60 seconds. Sampling frequency was 10kHz and electronic stethoscope and electro-goniometer were applied during the knee motion for data collection. The spectral analysis showed 3 peaks in both groups and the difference energy distribution in time-frequency domain. These results suggest that the diagnosis of knee joint pathology using the auscultation could be easier and more correct.