• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제11권2호
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• pp.3-8
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• 2007

In this paper a generalized parametric mean length $L(P^{\nu},\;R)$ has been defined and bounds for $L(P^{\nu},\;R)$ are obtained in terms of generalized R-norm information measure.

• 대한기계학회논문집B
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• 제22권1호
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• pp.34-49
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• 1998

In this study, turbulent flows in a grooved channel are numerically investigated by Large Eddy Simulation (LES). Especially, a parametric study is carried out to study effects of length and depth of a groove on large-scale flow structures. For one test case, comparison of LES results with those of DNS reveals a good agreement even though the number of grid points of LES is only 6.5% of that of DNS. This confirms that LES is a suitable tool for a parametric study of turbulent flows. The subsequent parametric study using LES shows that the large-scale turbulent structures are significantly affected by the geometry of the groove. Especially, when the length of the groove is short such that the recirculation region occupies the entire groove, the turbulent flow in the groove becomes very weak in both mean and fluctuation quantities.

• Communications for Statistical Applications and Methods
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• 제4권2호
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• pp.523-532
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• 1997

We propose several estimators of the reliability function R of the two-parameter exponential distribution, and then compare those estimator in terms of the mean square error (MSE) through Monte Carlo method. We also consider the parametric bootstrap estimation. Using the parametric bootstrap estimator, we obtain the bootstrap confidence intervals for reliability function and compare the proposed bootstrap confidence intervals in terms of the length and the coverage probability through Monte Carlo method.

• 수산해양기술연구
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• 제23권4호
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• pp.189-197
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• 1987

Parametric 음원을 어탐에 응용하기 위한 기초연구로써 본 실험에서는 parametric 음원의 특성을 조사하고 이 음원으로 어체에 대한 표적 강도를 측정하여 그 결과를 200KHz의 단일주파수 음원으로 측정한 결과와 비교.검토하였다. 그 결과를 요약하면 다음과 같다. 1. 200KHz인 단일주파수로 구동할 때의 지향각은 5.0$^{\circ}$였고, parametric 음원의 주파수가 5KHz, 10KHz, 16KHz, 20KHz일 때의 지향각은 각각 4.3$^{\circ}$, 2.2$^{\circ}$, 3.0$^{\circ}$, 2.5$^{\circ}$로서 주파수 저감비가 감소할수록 지향각이 예리하였으며 부엽은 전혀 나타나지 않았다. 2. parametric 음원의 주파수가 5KHz, 10KHz, 16KHz, 20KHz일 때의 음파변환효율은 각각 0.9%(Parametric 이득은 -41dB), 0.55%(parametric 이득은 -45dB), 0.1%(parametric 이득은 -60 dB), 0.04%(parametric 이득은 -68 dB)로 주파수 저감비가 감소할수록 음파변환효율은 급격히 낮아졌다. 3. parametric 음원으로 측정한 어체의 표적강도는 200KHz의 단일주파수 음원으로 측정한 표적강도에 비하여 단일어체일 때는 머리부분과 꼬리부분에서 5 dB씩 낮았으며 어체수가 2~3마리 일때는 머리부분과 꼬리부분에서 1~3 dB 정도 낮았으나 측면부분은 비슷하였다

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.502-507
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• 2003

Toward the development of practical methods for observed data oriented bispectral estimation, an automatic means for determining the smoothing bandwidth of bispectral windows is proposed, that can also provide an associated optimum bispectral estimate of stationary non-Gaussian signals, systematically only from an observed time series datum of finite length. For the conventional non-parametric bispectral estimation, the MSE (mean squared error) of the normalized estimate is reviewed under a certain mixing condition and sufficient data length, mainly from the viewpoint of the inverse relation between its bias and variance with respect to the smoothing bandwidth. Based on the fundamental relation, a systematic method not only for determining the bandwidth, but also for obtaining the optimum bispectral estimate is presented by newly introducing a MSE evaluation index of the estimate only from an observed time series datum of finite length. The effectiveness and fundamental features of the proposed method are illustrated by the basic results of numerical experiments.

• Journal of the Korean Data and Information Science Society
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• 제8권1호
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• pp.59-70
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• 1997

We introduce several estimators of the location and the scale parameters of the two-parameter exponential distribution, and then compare these estimators by the mean square error (MSE). Using the parametric bootstrap estimators and the delete-d jackknife, we obtain the bootstrap and the delete-d jackknife confidence intervals for the location and the scale parameters and compare the bootstrap confidence intervals with the delete-d jackknife confidence intervals by length and coverage probability through Monte Carlo method.

• International Journal of Air-Conditioning and Refrigeration
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• 제17권4호
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• pp.129-134
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• 2009

The objectives of this paper are to study the effects of thermal and geometric conditions on the performance of indoor heat exchangers with R-410A for Gas Engine Driven Heat Pump (GHP) application and to find the optimum design conditions of indoor heat exchangers by parametric analysis for the key parameters. The key parameters are number of tube row, number of tube pipe, fin pitch and transverse tube pitch. In the air side, moisture out of the humid air condenses on the fin surface while the refrigerant (R-410A) boils inside the smooth tube. Therefore this study uses Log Mean Enthalpy Difference (LMHD) method to analyze the heat transfer from the humid air to the refrigerant. This study determines the heat exchanger size, air side/refrigerant side pressure drop and overall heat transfer coefficient. Optimum design conditions for the key parameters are also determined by the parametric analysis. The results show that number of rows and pipes, fin pitch have significant effect on the heat exchanger size. It is also found that the tube length of the louver fin is $17{\sim}30%$ shorter than that of the plate fin.

• 말소리와 음성과학
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• 제9권1호
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• pp.41-47
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• 2017

The main advantage of the statistical parametric speech synthesis is its flexibility in changing voice characteristics. A personalized text-to-speech(TTS) system can be implemented by combining a speech synthesis system and a voice transformation system, and it is widely used in many application areas. It is known that the fundamental frequency and the spectral envelope of speech signal can be independently modified to convert the voice characteristics. Also it is important to maintain naturalness of the transformed speech. In this paper, a speech synthesis system based on Hidden Markov Model(HMM-based speech synthesis, HTS) using the STRAIGHT vocoder is constructed and voice transformation is conducted by modifying the fundamental frequency and spectral envelope. The fundamental frequency is transformed in a scaling method, and the spectral envelope is transformed through frequency warping method to control the speaker's vocal tract length. In particular, this study proposes a voice transformation method using the correlation between fundamental frequency and vocal tract length. Subjective evaluations were conducted to assess preference and mean opinion scores(MOS) for naturalness of synthetic speech. Experimental results showed that the proposed voice transformation method achieved higher preference than baseline systems while maintaining the naturalness of the speech quality.

• 한국구조물진단유지관리공학회 논문집
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• 제18권2호
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• pp.1-8
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• 2014

본 연구의 목적은 경계요소를 갖는 철근콘크리트 전단벽의 잠재소성힌지길이를 합리적으로 평가할 수 있는 단순모델의 제시이다. 전단벽의 높이에 따른 이상화된 곡률분포로부터, 기본방정식은 항복모멘트와 최대모멘트 그리고 사인장균열에 의한 부가모멘트의 함수로 일반화되었다. 전단벽의 항복모멘트와 최대모멘트는 변형률 적합조건과 힘의 평형조건을 기반하여 산정하였다. 사인장균열 발생의 여부는 ACI 318-11에서 제시된 콘크리트의 전단력으로부터 검토되었으며, 부가모멘트는 Park and Paulay에 의해 제시된 트러스기구를 이용하여 산정하였다. 이들 모멘트식들은 다양한 변수범위에서 변수연구를 수행하였다. 결과적으로 등가소성힌지길이는 주철근 및 수직철근지수와 축력지수의 함수로 제시될 수 있었다. 제시된 등가소성힌지길이의 모델은 실험결과의 비교에서 평균 및 표준편차가 각각 1.019와 0.102로 실험 결과를 정확하게 예측하였다.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.77-82
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• 2003

A parametric study was conducted on pressure drop in a catalytic converter for automobile. In this work, we proposed a new pressure drop relation which contains the various parameters needed to calculate and got a few results. In a monolith of catalyst, the flow originally turbulent flow changes to laminar flow and thus the pressure drop through the monolith is linearly proportional to the velocity. The exhaust pressure is doubly affected by the increase of mean velocity and length when we decrease the diameter of monolith while the volume keeps constant. Theoretical parameters such as $\alpha$ and $\beta$ are suggested to use as a reference value when there is no a experimental data. Especially in the part load test, these values should be modified to consider the property change of exhaust gas.