• Proceedings of the KIEE Conference
• /
• 2002.07b
• /
• pp.1338-1341
• /
• 2002

The Weibull probability density function and the Rayleigh function are compared by analyzing the relations of the capacity factors which are compared the actual wind speed frequency curve with which are modelled using the probability density functions with different mean wind speeds. For this analysis, the wind speed means of arithmetic, root mean square, cubic mean cuberoot, and standard deviations are computed from the measured wind speed data of a specific site and the coefficients of probability density functions are calculated. The capacity factors for Vestas 850[kW] wind turbine are calculated and analyzed. The results shows that the wind speed frequency curve by Rayleigh function is more close to the actual curve than by Weibull function. The more the wind speed frequency curve is close to the actual one, the more the capacity factors become large values.

• Honam Mathematical Journal
• /
• v.44 no.4
• /
• pp.594-617
• /
• 2022

In this study, firstly Smarandache ruled surfaces whose base curves are Smarandache curves derived from Frenet vectors of the curve, and whose direction vectors are unit vectors plotting Smarandache curves, are created. Then, the Gaussian and mean curvatures of the obtained ruled surfaces are calculated separately, and the conditions to be developable or minimal for the surfaces are given. Finally, the examples are given for each surface and the graphs of these surfaces are drawn.

• The Journal of the Acoustical Society of Korea
• /
• v.21 no.1
• /
• pp.37-41
• /
• 2002

In this paper, we made shorter EDT(early decay time) of room reverberation curve using multiple-channel. The speech signal was processed inverse filtering with full-band and sub-band in the basis MINT, and then the multiple-channel adaptive filters were used LMS (Least Mean Square) and NLMS (Normalized Least Mean Square) algorithm. Experimental results, we could get 1/3 of time reduction at 20dB level in the reverberation curve using full-band NLMS when two microphones were used. Also, it is shown that the speech articulation was improved 80% from the test listeners with the speech, which was to shorten EDT by MINT in the subjective assessments using real room impulse response.

• Journal of the Korean Data and Information Science Society
• /
• v.10 no.2
• /
• pp.369-385
• /
• 1999

For the growth curve model with arbitrary covariance structure, known as unstructured covariance matrix, the problems of detecting outliers are discussed in this paper. In order to detect outliers in the growth curve model, the likelihood ratio testing statistics in mean shift model is established and its distribution is derived. After we detected outliers in growth curve model, we test homo and/or hetero-geneous covariance matrices using PSR Quasi-Bayes Criterion. For illustration, one numerical example is discussed, which compares between before and after outlier deleting.

• Publications of The Korean Astronomical Society
• /
• v.30 no.2
• /
• pp.225-227
• /
• 2015

We introduce a code called tlc_s05, to fit sparsely sampled JHK band Cepheid light curve data with template light curves to derive the mean magnitude. A brief description of the code is provided here. We tested the performance of the code in deriving the mean JHK band magnitudes using simulations, and we found that it is better to observe more than four evenly spaced data points per light curve, which permits tlc_s05 to derive accurate mean magnitudes for Cepheid JHK band light curves.

• Journal of Integrative Natural Science
• /
• v.7 no.1
• /
• pp.67-73
• /
• 2014

We consider the mean value function for NHPP software reliability model and time series regression model in software failure data. We estimate parameters for the proposed models from two data sets. The values of SSE and MSE is presented from two data sets. We compare the predicted number of faults with the actual two data sets using the mean value function and regression curve.

• Journal of applied mathematics & informatics
• /
• v.40 no.3_4
• /
• pp.587-601
• /
• 2022

We find the characterizations of the curvatures of Legendre curves and magnetic curves in Kenmotsu manifolds with C-parallel and C-proper mean curvature vector fields in the tangent and normal bundles. Finally, an illustrative example is presented.

• Journal of Korean Society on Water Environment
• /
• v.21 no.5
• /
• pp.516-519
• /
• 2005

An useful protocol coiled load duration curve methodology to estimate contaminant loading to a river on an exceedance probability scale was developed in this research. The technique was further applied to estimate total coliform loading to the Geum River, using the daily mean flow rate and total coliform concentration data during January, 1996 and July, 2004 for the Gongju where an automated monitoring station is located. Drought flow of the Gongju (=50.3 cms) was equivalent to 40% on an exceedance probability scale. Load duration curve for total coliform loading at the Gongju was constructed. Standard duration curve was constructed with the water quality criteria for the class 2 (total coliform concentration = 1000 MPN/100 mL). By plotting load duration curve with standard duration curve, it could be revealed that water quality do not meet the desired water quality for 47% on an exceedance probability scale. If linearity between flow rate and coliform concentration is assumed, it can be interpretated that water quality exceeds desired criteria when average mean flow rate is over 51 cms.

• Journal of Korean Society for Quality Management
• /
• v.23 no.1
• /
• pp.95-105
• /
• 1995

The error structure of nonlinearized technological growth models, such as, the Pearl curve, the Gompertz curve and the Wei bull growth curve, has zero mean and a constant variance over time. Transformed models, however, like the linearized Fisher-Pry model. the linearized Gompertz growth curve, and the linearized Weibull growth curve have increasing variance from t = 0 to the inflection point.

• Communications for Statistical Applications and Methods
• /
• v.20 no.3
• /
• pp.169-174
• /
• 2013

The ROC curve is drawn with two conditional cumulative distribution functions (or survival functions) of the univariate random variable. In this work, we consider joint cumulative distribution functions of k random variables, and suggest a ROC curve for multivariate random variables. With regard to the values on the line, which passes through two mean vectors of dichotomous states, a joint cumulative distribution function can be regarded as a function of the univariate variable. After this function is modified to satisfy the properties of the cumulative distribution function, a ROC curve might be derived; moreover, some illustrative examples are demonstrated.