• Communications for Statistical Applications and Methods
• /
• v.30 no.3
• /
• pp.227-244
• /
• 2023

In this paper, a depth-based nonparametric test for a multivariate two-sample scale problem is proposed. The proposed test statistic is based on the depth-induced ranks and is thus distribution-free. In this article, the depth values of data points of one sample are calculated with respect to the other sample or distribution and vice versa. A comprehensive simulation study is used to examine the performance of the proposed test for symmetric as well as skewed distributions. Comparison of the proposed test with the existing depth-based nonparametric tests is accomplished through empirical powers over different depth functions. The simulation study admits that the proposed test outperforms existing nonparametric depth-based tests for symmetric and skewed distributions. Finally, an actual life data set is used to demonstrate the applicability of the proposed test.

• Journal of the Korean Home Economics Association
• /
• v.20 no.2
• /
• pp.135-140
• /
• 1982

As a step preliminary to the factor-analysis of a child-rearing attitude scale under construction, its preliminary form containing a total of 368 self-answered questions was administerd to 88 married women with one or more children in the grade school age. all graduates of colleges and in possession of a home telephone and a house, twice from one week apart. The test-retest correlation coefficients, calculated for each test item based on the subject's choice among the three response alternatives on two test ocasions, ranged from .80 to .10. The cut-off point of r=.41 or lower led to the elimination of 48 items. As a point of incidental interest, the rate of response concordance. The namber of subjects giving the same categroy response on two occasions was calculated for each item and it was correlated with its test. retest correlation coefficient. The two different indices of item test-retest reliability were found not related to each other. Empirical evidence, as well as rational justifications, was presented to show that the correlation coefficient is the better of the tow indices of item test-retest reliability.

• The Journal of Fisheries Business Administration
• /
• v.40 no.2
• /
• pp.49-70
• /
• 2009

This study proviedes GARCH model(Bollerslev, 1986) to analyze the structural characteristics of price volatility in domestic aquacultural fish market of Korea. As a case study, flatfish and rock-fish are analyzed as major species with relatively high portion in an aspect of production volume among fish captured in Korea. For analyzing, this study uses daily market data (dating from Jan 1 2000 to June 30, 2008) published by the Noryangjin Fisheries Wholesale Market which is located in Seoul of Korea. This study performs normality test on trading volume and price volatility of flatfish and rock-fish as an advanced empirical approach. The normality test adopted is Jarque-Bera test statistic. As a result, first, a null hypothesis that "an empirical distribution follows normal distribution" was rejected in both fishes. The distribution of daily market data of them were not only biased toward positive(+) direction in terms of kurtosis and skewness, but also characterized by leptokurtic distribution with long right tail. Secondly, serial correlations were found in data on market trading volume and price volatility of two species during very long period. Thirdly, the results of unit root test and ARCH-LM test showed that all data of time series were very stationary and demonstrated effects of ARCH. These statistical characteristics can be explained as a reasonable ground for supporting the fitness of GARCH model in order to estimate conditional variances that reveal price volatility in empirical analysis. From empirical data analysis above, this study drew the following conclusions. First of all, from an empirical analysis on potential effects of seasonality and the day of week on price volatility of aquacultural fish, Monday effects were found in both species and Thursday and Friday effects were also found in flatfish. This indicates that Monday is effective in expanding price volatility of aquacultural fish market and also Monday has higher effects upon the price volatility of fish than other days of week have since it has more new information for weekend. Secondly, the empirical analysis led to a common conclusion that there was very high price volatility of flatfish and rock-fish. This points out that the persistency parameter($\lambda$), an index of possibility for current volatility to sustain similarly in the future, was higher than 0.8-equivalently nearly to 1-in both flatfish and rock-fish, which presents volatility clustering. Also, this study estimated and compared and model that hypothesized normal distributions in order to determine fitness of respective models. As a result, the fitness of GARCH(1, 1)-t model was better than model where the distribution of error term was hypothesized through-distribution due to characteristics of fat-tailed distribution, was also better than model, as described in the results of basic statistic analysis. In conclusion, this study has an important mean in that it was introduced firstly in Korea to investigate in price volatility of Korean aquacultural fishery products, although there was partially a limited of official statistic data. Therefore, it is expected that the results of this study will be useful as a reference material for making and assessing governmental policies. Also, it is looked forward that the results will be helpful to build a fishery business plan as and aspect of producer, and also to take timely measures to potential price fluctuations of fishery products in market. Hence, it is advisable that further studies related to such price volatility in fishery market will extend and evolve into a wider variety of articles and issues in near future.

• Journal of the Korean Institute of Gas
• /
• v.17 no.3
• /
• pp.20-26
• /
• 2013

In this research, an empirical study on the designed burst pressure of Type3 composite cylinder was performed by hydrostatic burst test equipment. The designed burst pressure of Type3 composite cylinders, which are 6.8 liter and 31 MPa of service pressure, was estimated with the analysis using the finite element method. In order to confirm its accuracy, the burst test of small Type3 composite cylinders was perfomed through three times. The burst test equipment can pressurize to 400 MPa. As a result of comparison between the designed burst pressure and actual burst pressure, the difference was less than 4 percentage. With a test result, the analysis accuracy was verified. This technique will be applied to both qualification and inspection for the composite cylinder.

• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.1663-1666
• /
• 1997

The purpose of this paper is to find how to determine the controllability and stability derivatives form flight test and to display the stability of the Twinbee aircraft. There are various methods developed to find the derivatives : wind tunnel testing, predicted result from empirical data, flight test and so on. Among those methods, the estimation form flight test of real aricraft is the most reliable. We performed the flight test of Twinbee and recorded the states of aorcraft. Using those states and parameter setimation algorithem based on the Maximum Likdlihood(MMLE) criterion, we can estimate the controllability and stability derivatives. In this paper, wel will show the process form designing the proper flight test input to estimation of derivatives.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.31-36
• /
• 2003

In this study a relationship between SP curves and tensile properties was investigated by FE analysis on SP test with various assumed tensile properties. For the accuracy of FE analysis, SP test and tensile test were performed and those results were compared with FE analysis results. The yield load(Py) defined from the intersection point of two lines tangent to the elastic bending region and plastic bending region. And it was related specifically with yield stress(${\sigma}_0$) in FE analysis result curves. The slopes of FE analysis result curves normalized by yield stress(${\sigma}_0$) reflected the change of tensile properties regardless of yield stress(${\sigma}_0$) variation. Empirical relations were derived from these results. Tensile properties from these relations showed good agreement in FE analysis curve and tested curve.

• Journal of the Korean Home Economics Association
• /
• v.37 no.2
• /
• pp.159-174
• /
• 1999

This study was to develop the counseling and education program for coping with physical, emotional, and verbal abuse between spouses. Results of empirical study of spouse abuse provided for the basis of designing this program. Consisting of 12 sessions (4 sessions of counseling and 8 sessions of education), the program was delivered to 10 marital couples in an area of Kyunggi-do province. The effectiveness of the program was evaluated through one-group pre-test, post-test, and follow-up test design. Semi-structured interview technique was also employed to evaluate the effectiveness. Resets of paired t-test showed that there were significant differences in several variables between pre-test and post-test period, and this effectiveness remained until follow-up. period. In particular, the degrees of verbal abuse of husbands, and of physical abuse of both husbands and wives were significantly decreased after participating in the program. Also, for both husbands and wives, the Levels of self-esteem and of quality of communication were increased, while the degree of depression was significantly decreased.

• Journal of Korean Society for Quality Management
• /
• v.18 no.1
• /
• pp.29-39
• /
• 1990

In this paper we propose a nonparametric test for testing the equality of several regression lines against ordered alternatives, when the independent variables are positive and all regression lines have a common intercept. The proposed test is based on a Jonckheere-type statistic applied to residuals. Under some conditions our proposed test statistic is asymptotically distribution-free. The small-sample powers of our test are compared with other tests by a Monte Carlo study. The simulation results show that the proposed test has significantly higher empirical powers than the other tests considered in this paper.

• Journal of the Korean Statistical Society
• /
• v.26 no.2
• /
• pp.261-276
• /
• 1997

In the context of binary response regression, the problem of constructing Bayesian goodness-of-link test for testing logit link versus probit link is considered. Based upon the well known facts that cdf of logistic variate .approx. cdf of $t_{8}$/.634 and, as .nu. .to. .infty., cdf of $t_{\nu}$ approximates to that of N(0,1), Bayes factor is derived as a test criterion. A synthesis of the Gibbs sampling and a marginal likelihood estimation scheme is also proposed to compute the Bayes factor. Performance of the test is investigated via Monte Carlo study. The new test is also illustrated with an empirical data example.e.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.07b
• /
• pp.391-393
• /
• 2005

DMS(Data Management Server)시스템은 DVM(Digital Variable Multi Air conditioning system) 관리, 제어, 모니터링을 수행하는 시스템으로 OSGi Service Platform을 미들웨어로 채택하고 있다. 본 논문에서는 OSGi Alliance에서 제공하는 Test Harness와 Test Suite을 기반으로 본 연구진이 개발한 OSGi Automated Test Toolkit인 MIRACLE을 이용한 DMS시스템 테스트 사례 연구에 관해 기술한다. 본 논문을 통해, MIRACLE을 이용한 임베디드 시스템에서의 OSGi Service Platform의 테스트 자동화에 대해 기여 할 수 있도록 한다.