• Korean Journal of Biological Psychiatry
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• v.16 no.2
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• pp.76-111
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• 2009

Objectives : The purpose of this study was to develop the Korean version of the Social Functioning Scale (KSFS) in the patients with schizophrenia. Methods : KSFS was administered to 90 schizophrenic patients and 80 their parents and 90 normal controls for examining the reliability and validity. Results : Data analysis showed statistically significant reliabilities and validities of KSFS. The test-retest reliability, rater vs. self-report reliability, and internal consistency for total scores of KSFS were 0.93, 0.44 and 0.94 respectively. Evidence for discriminant validity of KSFS comes from the results that the mean scores of schizophrenic patients were significantly higher than those of normal controls. Construct validity was assessed by calculating the 7 inter-areas correlations of the KSFS, and all areas were statistically significant. Significant correlations between the total scores of KSFS and those of SOFAS lend support for the concurrent validity of this instrument. Factor analyses were performed and two factors were extracted accounting for 63.7% of the variance. Sensitivity was assessed indirectly via the distribution and range of scores on the SFS. The normal control group showed a distribution around a higher mean with a moderate positive skew. Conclusion : KSFS was found to be a valid, reliable, and sensitive instrument which can be used to evaluate the degree of social functioning in the patients with schizophrenia.

• The Korean Journal of Applied Statistics
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• v.24 no.3
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• pp.547-557
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• 2011

In this paper we developed a statistical model for traffic volume data which collected from a spot of specific local state road. One peculiar property of daily traffic data is that it has bimodal shape which have two peaks on times of both going to office and coming back to home. So, various mixture models of circular distribution are suggested for bimodal traffic data and EM algorithms are applied to estimate the parameters of the suggested models. To compare the accuracy of the suggested models, classical regressions with dummy variables are also considered. The suggested models for traffic volumn data can be effectively used to estimate missing values due to measuring instrument disorder.

• Communications for Statistical Applications and Methods
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• v.19 no.5
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• pp.685-696
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• 2012

These days the interest of quality leads to the necessity of control charts for monitoring the process in various fields of practical applications. The $\overline{X}$ chart is one of the most widely used tools for quality control that also performs well under the normality of quality characteristics. However, quality characteristics tend to have nonnormal properties in real applications. Numerous recent studies have tried to find and explore the performance of $\overline{X}$ chart due to non-normality; however previous studies numerically examined the effects of non-normality and did not provide any theoretical justification. Moreover, numerical studies are restricted to specific type of distributions such as Burr or gamma distribution that are known to be flexible but can hardly replace other general distributions. In this paper, we approximate the false alarm rate(FAR) of the $\overline{X}$ chart using the Edgeworth expansion up to 1/n-order with the fourth cumulant. This allows us to examine the theoretical effects of nonnormality, as measured by the skewness and kurtosis, on $\overline{X}$ chart. In addition, we investigate the effect of skewness and kurtosis on $\overline{X}$ chart in numerical studies. We use a skewed-normal distribution with a skew parameter to comprehensively investigate the effect of skewness.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.406-417
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• 2014

This paper presents a numerical optimization method to improve the performance of the propeller with Turbo-Ring using real-coded genetic algorithm. In the presented method, Unimodal Normal Distribution Crossover (UNDX) and Minimal Generation Gap (MGG) model are used as crossover operator and generation-alternation model, respectively. Propeller characteristics are evaluated by a simple surface panel method "SQCM" in the optimization process. Blade sections of the original Turbo-Ring and propeller are replaced by the NACA66 a = 0.8 section. However, original chord, skew, rake and maximum blade thickness distributions in the radial direction are unchanged. Pitch and maximum camber distributions in the radial direction are selected as the design variables. Optimization is conducted to maximize the efficiency of the propeller with Turbo-Ring. The experimental result shows that the efficiency of the optimized propeller with Turbo-Ring is higher than that of the original propeller with Turbo-Ring.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1037-1044
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• 2020

Since radar wind profiler (RWP) provides wind field data with high time and space resolution in all weather conditions, their verification of the accuracy and quality is essential. The simultaneous wind measurement from rawinsonde is commonly used to evaluate wind vectors from RWP. In this study, the simulation algorithm which produces the spectrum and raw time series (I/Q) data from the average values of moments is presented as a step-by-step verification method for the signal processing algorithm. The possibility of the simulation algorithm was also confirmed through comparison with the raw data of LAP-3000. The Doppler power spectrum was generated by assuming the density function of the skew-normal distribution and by using the moment values as the parameter. The simulated spectrum was generated through random numbers. In addition, the coherent averaged I/Q data was generated by random phase and inverse discrete Fourier transform, and raw I/Q data was generated through the Dirichlet distribution.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.343-348
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• 1984

Variation of soil properties within mapping unit of lava plain soils was statistically summarized. Properties such as particle size distribution, moisture retention, color, pH, and CEC are relatively unaffected by soil management while Na, K, base saturation, and available $P_2O_5$ most affected by management. These soils were correctly classified with regard to order at 66.5, to greatgroup at 56.0, and to series at 43.8%. CV values greater than 90% could be symptomatic of skew distribution. Distributions of sand content and some chemical properties were log-normal.