• KIPS Transactions on Software and Data Engineering
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• v.11 no.2
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• pp.67-80
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• 2022

Recently, many laundry home appliances have been released with Internet of Things (IoT) functions, but there are few quality evaluation tests for IoT functions. In particular, since IoT test items are not prepared for laundry home appliances applied with IoT functions, it is difficult to find the cause even if defects occur, and test institutions are limited in selecting test items related to IoT and conducting proper performance tests. In this paper, we design a test item framework that separates IoT test items into commonality and variability to identify product defects and causes for laundry home appliances with IoT features among products in the field of home appliances. Through the proposed research, manufacturers and test institutions can test the proper performance of laundry products with IoT functions, which can improve the completeness of the products and ensure reliability.

• Journal of Oriental Neuropsychiatry
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• v.33 no.1
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• pp.33-48
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• 2022

Objectives: Academic stress poses a significant risk for the mental health of medical students, and a feasible group intervention program for managing academic stress is required. The purpose of this study was to examine the clinical effectiveness of emotional freedom techniques (EFT) on the mental health of Korean medical students. Methods: The class of first-year medical school students (n=36) participated in an after-school EFT group intervention program comprising six sessions (15 minutes/session, three weeks) to analyze its clinical effectiveness as a single-group test-retest clinical study. The changes in the Perceived Stress Scale (PSS), Test Anxiety Inventory (TAI), Positive and Negative Affect Schedule (PANAS), and State-Trait Anxiety Inventory (STAI) scores were examined using a paired t-test and Cohen's D at post-EFT and two-week follow-up. Results: There were significant curtailments at post-EFT and follow-up measures in TAI-Total (t=2.704 and t=3.289), TAI-Worry (t=2.297 and t=2.454), TAI-Emotionality (t=2.763 and t=3.654), PSS-Negative Perspective (t=2.659 and t=3.877), and PANAS-Negative Affect (t=2.885 and t=3.259) subscales, however not in PSS-Positive Perspective (t=-1.279 and t=-1.101) and PANAS-Positive Affect (t=0.194 and t=-0.122) subscales. The trait anxiety (t=2.227) was significantly mitigated in the post-EFT measure and the state anxiety (t=2.30) in the follow-up measure. Conclusions: The EFT group intervention alleviated test stress, negative affect, and anxiety in the Korean medical students. This study contributes to an understanding of academic stress and EFT intervention in the competitive environment of medical education.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.409-416
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• 2019

The purpose of this study was to investigate the effect of horticulture activity program on self-esteem and school life adaptation of multicultural adolescent. A non-equivalent control group pre-post test design with experimental group (n=39) and control group (n=36) was used. The program was conducted from Jan. 2 to Feb. 28, 2017, and the questionnaire was conducted before and after the program. Collected data was analyzed by SPSS(Ver, 24.0), conducting ${\chi}^2-test$, Fisher's exact test, t-test, paired t-test. There were statistically significant increase in self-esteem(t=2.41, p=.021) and school life adaptation(t=3.85, p=.000) by difference between a pretest and a posttest in the experimental group compared to that in the control group. Therefore, the horticulture activity program for multicultural adolescent have a significant effect for better performance of self-esteem and school life adaptation. Also, It was confirmed that the program used for improving adaptability of multicultural adolescent.

• Interdisciplinary Bio Central
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• v.2 no.2
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• pp.4.1-4.6
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• 2010

The most common type of microarray experiment has a simple design using microarray data obtained from two different groups or conditions. A typical method to identify differentially expressed genes (DEGs) between two conditions is the conventional Student's t-test. The t-test is based on the simple estimation of the population variance for a gene using the sample variance of its expression levels. Although empirical Bayes approach improves on the t-statistic by not giving a high rank to genes only because they have a small sample variance, the basic assumption for this is same as the ordinary t-test which is the equality of variances across experimental groups. The t-test and empirical Bayes approach suffer from low statistical power because of the assumption of normal and unimodal distributions for the microarray data analysis. We propose a method to address these problems that is robust to outliers or skewed data, while maintaining the advantages of the classical t-test or modified t-statistics. The resulting data transformation to fit the normality assumption increases the statistical power for identifying DEGs using these statistics.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.6
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• pp.737-745
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• 2008

Recent developments of process and measurement technology bring much interest to the online monitoring of process operations such as milling, grinding, broaching, etc. The objective of online monitoring systems is to detect process changes as early as possible. This is helpful in protecting facilities against unexpected failures and then preventing unnecessary loss. This paper investigates, when the process monitoring data are obtained as a profile, the monitoring performances of a statistical $T^2$-statistic and a feedforward neural network by using a wavelet transform. Numerical experiments using cutting force data presented by Axinte show that the proposed wavelet based $T^2$-test has an acceptable power in detecting profile changes. However, its operating characteristic is very sensitive to autocorrelation. On the contrary, compared with $T^2$-test, the neural network has more stable performance in the presence of autocorrelation. This indicates that an adaptive feature to analyze noises should be incorporated into the wavelet based $T^2$-test.

• Proceedings of the Korean Statistical Society Conference
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• 2005.11a
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• pp.167-173
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• 2005

This paper presents an autocorrelation test that is applicable to dynamic panel data models with serially correlated errors. The residual-based GMM t-test is a significance test that is applied after estimating a dynamic model by using the instrumental variable(IV) method and is directly applicable to any other consistently estimated residuals. Monte Carlo simulations show that the t-test has considerably more power than the $m_2$ test or the Sargan test under both forms of serial correlation (i.e., AR(1) and MA(1)).

• Korean Journal of Veterinary Research
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• v.37 no.3
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• pp.613-618
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• 1997

Direct competitive enzyme linked immunosorbent assay(ELISA) with monoclonal antibodies have been studied for quantitative determination of T-2 toxin from the mold corn. The T-2HS, T-2HS-BSA, T-2HS-HRP and monoclonal antibodies against T-2 toxin produced in the studies were qualified for quantitative ELISA test of T-2 toxin. The mean recovery rate from ground com spiked T-2 toxin was 83%. The meaning range of the T-2 test was 60ng to $2{\mu}g$. According to the recovery results with the com spiked T-2, the tests proved to be suitable in the screening of the moldy feed samples for the presence of T-2 toxin and will be able to become the basis of the ELISA test for the quantitative screening kits of T-2 toxin.

• Journal of Integrative Natural Science
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• v.15 no.1
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• pp.9-18
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• 2022

This research examines the power of bootstrap two-sample test, and compares it with the powers of two-sample t-test and Wilcoxon rank sum test, through simulation. For simulation work, a positively skewed and heavy tailed distribution was selected as a population distribution, the chi-square distributions with three degrees of freedom, χ²₃. For two independent samples, the fist sample was selected from χ²₃. The second sample was selected independently from the same χ²₃ as the first sample, and calculated d+ax for each sampled value x, a randomly selected value from χ²₃. The d in d+ax has from 0 to 5 by 0.5 interval, and the a has from 1.0 to 1.5 by 0.1 interval. The powers of three methods were evaluated for the sample sizes 10,20,30,40,50. The null hypothesis was the two population medians being equal for Bootstrap two-sample test and Wilcoxon rank sum test, and the two population means being equal for the two-sample t-test. The powers were obtained using r program language; wilcox.test() in r base package for Wilcoxon rank sum test, t.test() in r base package for the two-sample t-test, boot.two.bca() in r wBoot pacakge for the bootstrap two-sample test. Simulation results show that the power of Wilcoxon rank sum test is the best for all 330 (n,a,d) combinations and the power of two-sample t-test comes next, and the power of bootstrap two-sample comes last. As the results, it can be recommended to use the classic inference methods if there are widely accepted and used methods, in terms of time, costs, sometimes power.

• Journal of Korean Society for Quality Management
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• v.29 no.2
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• pp.37-45
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• 2001

A survival variable is a non-negative random variable X with distribution function F(t) satisfying F(0) : 0 and a survival function F(t): 1-F(t). This variable is said to be New Better than Used of specified age t$_{0}$ if F(x+ t$_{0}$)$\leq$F(x).F(t$_{0}$) for all x$\geq$0 and a fixed t$_{0}$. We propose the test for H$_{0}$ : F(x+t$_{0}$)=F(x).F(t$_{0}$) for all x$\geq$0 against H$_1$: F(x+t$_{0}$) $\leq$ F(x).F(t$_{0}$) for all x$\geq$0 when the specified age to is unknown but can be estimated from the data when t$_{0}$=ζ$_{p}$, the pth percentile of F. This test statistic, which is based on the normalized spacings between the ordered observations, is readily applied in the case of small sample. Also, our test is more simple than Ahmad's test (1998). Finally, the performance of our test is presented.our test is presented.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.2
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• pp.250-256
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• 2017

Automatic transmission(A/T) is one of a car's core components. The durability of A/T has an effect on the durability of the car. The input shaft of A/T passes the power directly from the engine, so the durability of the input shaft for A/T is likewise vital. In this study, the test method of the input shaft is considered and the load spectrum of A/T is analyzed to secure durability of the input shaft. The shape parameter, T-N curve of the input shaft torsional fatigue test are obtained for life evaluation and analysis. Results of this study can be used to get the basic background of the durability test for A/T components.