• Journal of the Korean Data and Information Science Society
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• 제18권2호
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• pp.525-534
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• 2007

It is a common practice in many research areas that multiple range tests for a between subject factor such as Tukey are applied to a within subject factor in a repeated measures design. Tukey procedure, however, sometimes detects no pairs with different means even when the hypothesis of all equal level means is rejected. This study attempts to provide a rationale for the proposition that Tukey is inappropriate post hoc procedure for a within subject factor in which the observations are correlated. We introduce two multiple range tests, Bonferroni and Scheffe, for a within subject factor and show that Bonferroni is more appropriate than Scheffe for pairwise multiple comparisons. Subsequent simulation study indicates that Tukey has significantly less power than Bonferroni in detecting actual difference between means of some pairs when the observations of a within subject factor are highly correlated.

• 한국정밀공학회지
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• 제18권12호
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• pp.110-115
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• 2001

In this paper, a multiple comparison was proposed to minimize the amount of coolant. And new coolant level, called "low level", was suggested to show usefulness of multiple comparison for experiments. The amount of this levee is about 1/4 of conventional coolant amount-called "high level", and dry cutting is called "none level". Using these coolant levels, the cutting temperatures of each coolant level in turning process were analyzed by analysis of variance(ANOYA)-test and a multiple comparison. As the result of ANOVA-test, we have just known that the average of temperature of each coolant level is not equal. However by Tukey's HSD, one of multiple comparison. it was analyzed that the average of temperature of low level is similar to that of high levee and different from that of none level.erent from that of none level.

• Journal of Mechanical Science and Technology
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• 제18권12호
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• pp.2182-2189
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• 2004

In the recent years, environmentally conscious design and manufacturing technologies have attracted considerable attention. The coolants, lubricants, solvents, metallic chips and discarded tools from manufacturing operations will harm our environment and the earth's ecosystem. In the present work, the Tukey method of multiple comparisons is used to select the minimum level of coolant required in a turning process. The amount of coolant is varied in 270 designed experiments and the parameters cutting temperature, surface roughness, and specific cutting energy are carefully evaluated. The effects of coolant mix ratio as well as the amount of coolant on the turning process are studied in the present work. The cutting temperature and surface roughness for different quantity of coolant are investigated by analysis of variance (ANOVA) - test and a multiple comparison method. ANOVA-test results signify that the average tool temperature and surface roughness depend on the amount of coolant. Based on Tukey's Honestly Significant Difference (HSD) method, one of the multiple comparison methods, the minimum level of coolant is 1.0 L/min with 2% mix ratio in the aspect of controlling tool temperature. F-test concludes that the amount of coolant used does not have any significant effect on specific cutting energy. Finally, Tukey method ascertains that 0.5 L/min with 6% mix ratio is the minimum level of coolant required in turning process without any serious degradation of the surface finish. Considering all aspects of cutting, the minimum coolant required is 1.0 L/min with 6% mix ratio. It is merely half the coolant currently used i.e. 2.0 L/min with 10% mix ratio. Minimal use of coolant not only economically desirable for reducing manufacturing cost but also it imparts fewer hazards to human health. Also, sparing use of coolant will eventually transform the turning process into a more environment-conscious manufacturing process.

• Communications for Statistical Applications and Methods
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• 제16권1호
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• pp.75-83
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• 2009

단순선형 회귀모형의 기울기에 대한 평행성 검정법을 제안하였다. 세 군 이상에서 기울기에 대하여 Tukey (1953)가 제안한 HSD방법을 이용한 모수적 검정법과 Kruskal-Wallis (1952) 검정법을 이용한 비모수적 검정법을 각각 제안하였다. 또한 모의실험을 통하여 기존의 검정법과 제안한 검정법의 검정력을 비교하였다.

• 품질경영학회지
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• 제45권4호
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• pp.933-942
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• 2017

Purpose: The purpose of this paper is to evaluate the performance quality of the open source DBMSs. Performance quality is defined as processing time for Join queries. Query processing time is measured and compared in the most widely used open source DBMSs and commercial DBMS. Methods: By varying the number of tuples of two relations to be joined, the average processing time(seconds) of a Join query in each DBMS was obtained experimentally. ANOVA and Tukey HSD test were used in order to compare the performance quality of DBMSs. Results: There was a significant difference between the performance qualities of the three DBMSs at all experimental levels where the number of tuples was 100, 1,000, 2,000, 10,000, and 50,000. As a result of the Tukey HSD test, two open source DBMSs (MariaDB, MySQL) were classified in the same group only at the tuple level of 100. The commercial DBMS (MS-SQL Server) belonged to another group. At level of more than 1,000 tuples, all three DBMSs belonged to different groups. Conclusion: Within the open source DBMS group, MariaDB showed the better performance quality except for a small number of tuples. Thus the results show that MariaDB can be the alternative to MySQL which is currently most widely used. Between open source DBMS and commercial DBMS groups, MS-SQL Server always shows the best performance quality, but the less number of tuples, the less the difference.

• 대한치과기공학회지
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• 제18권1호
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• pp.67-72
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• 1996

This test is verifying for influence of W/P ratio of investment upon dental prosthesis Firstly we made 40 MOD die and divide 4 groups, each group take 0.2 different w/p ratio grade such as 0.35, 0.37, 0.39 and 0.41. The method of data analysis applied were by ANOVA, Tukey test and Mann-Whiney and Kruskal Wallis test. The finding of this study were as follows : 1. The 0.37 w/p ratio group showed most accurte margin due to $15.8{\mu}m$ gap between margin and die which keep up with manufacture's instruction and 0.35 w/p ratio group was followed as second accuracy group o 새 $48.3{\mu}m$ gap between margin and die, 0.39 w/p ratio group showed $101{\mu}m$ gap and 0.41 w/p ratio group showed $129.8{\mu}m$ gap. 2. As to the relationship of the margin accuracy between 4 different grade of w/p ratio groups, each group was statistically significant(P<0.01). Also the all groups were statistically significant except between 0.35 and 0.37 groups between 0.39 and 0.41 groups, and between 0.35 and 0.39 groups. 3. A consequence of Mann-Whitney & Kruskal-Wallis test for marginal accuracy between 4 different grade of w/p ratio was statistically significant as same as above ANOVA test result. Also Tukey test for verifying similarity from each group showed same as above.

• 한국도로학회논문집
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• 제15권6호
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• pp.61-68
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• 2013

PURPOSES : The purpose of this study is to study the noise reducing effect of Micro Surfacing by comparing general asphalt, longitudinal tining and Slurry Seal. METHODS : This study measures vehicles' noise of each section by the NCPX method that can measure noise between the road surface and the tire at the field. Total sound pressure and sound pressure level by the 1/3 octave band frequency are calculated through the field data of each section. Total sound pressure level is compared by ANOVA test statistically. After ANOVA test, post-hoc test is conducted to know mean difference of surface type by Tukey. RESULTS : As the result of CPB analysis to confirm sound pressure levels by frequency, it was shown that sound pressure levels by frequency are totally similar except for those of frequency bands between 100Hz and 500Hz. The result of ANOVA test and post-hoc test, it was shown that sections of surface type have a difference. The result of Micro Surfacing was lower 2~5dB(A) than other surface type. CONCLUSIONS : It is found that the noise reduction performance of Micro Surfacing was better than other surface type.

• 대한치과보철학회지
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• 제54권3호
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• pp.218-225
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• 2016

목적: 본 연구에서는 자가-접착 레진 시멘트의 접착 강도에 포스트의 표면 처리와 접착 시스템이 미치는 영향을 조사하고자 하였다. 재료 및 방법: 비슷한 치근 길이를 가진 48개의 사람 상악 단근치를 사용하여 160개의 시편을 제작하고 접착 시스템에 따라 4개의 군으로 분류하였다(no adhesive, Adper Single Bond 2, Clearfil SE Bond, Clearfil S3). 각 군은 포스트 표면 처리 방식에 따라 다시 4개의 군으로 세분하였다(no treatment, sandblast, silane, sandblast and silane). 포스트를(Parapost Fiber White) Rely X Unicem을 사용하여 접착하였다. 치아를 장축에 수직으로 1 mm 두께로 절단 하였다. Push-out test를 0.5 mm/분의 crosshead speed로 시행하였다. 2-way ANOVA, 1-way ANOVA 검정을 시행하였고 Tukey test를 통한 사후 검정을 시행하였다(${\alpha}=0.05$). 결과: Tukey test를 통한 사후 검정에서 접착 시스템에 따른 차이가 나타났다. Clearfil SE Bond가 가장 높은 접착 강도를 나타내었다. 결론: 상아질에 Clearfil SE bond를 사용하고 포스트를 실란 처리시 가장 높은 접착 강도를 나타내었다.

• 생태와환경
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• 제39권2호통권116호
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• pp.209-218
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• 2006

두 종의 초식성 동물플랑크톤(Daphnia magna. Moina macrocopa)의 직접노출 밀도차(0, 4, 8개체)와 동물플랑크톤 배양여과액(ZCMF) 농도차(0, 25, 50%)에 따른, 두남조 Microcystis aeruginosa와 Planktothrix agardhii의 생체량과 세포내 microcystin(MC)을 1일 간격으로 측정하였고, 직접노출실험의 경우 동물플랑크톤 생존륜을 1일 간격으로 관찰하였다. 동물플랑크톤 직접노출 실험 결과, 두 균주에서 세포내 MC함량이 증가하였으며 (rm-ANOVA: P< 0.039), P. agardhii균주에서는 4개체 처리군(ZT1)보다 8개체 처리군(ZT2)에서 통계적으로 유의한 수준으로 높은 세포내 MC값이 관찰되었다(Tukey test. P<0.082).세포내 MC가 최고값을 보인 3일 또는 4일째에, 처리군들은 대조군에 비하여 통계적으로 유의한 차이를 보였다(One-way ANOVA, P< 0.021). ZCMF에 노출시킨 M. aeruginosa균주에서 세포내 MC함량이 통계적으로 유의한 수준으로 차이가 있었다(rm-ANOVA: P< 0.004), 실험기간동안 세포내 MC값은 M. aeruginosa균주에서 25%처리군 보다 50%처리군에서 통계적으로 유의한 수준으로 높게 나타났다(Tukey test, Plt; 0.025). 본연구결과, 세포내 MC량은 초식성 동물플랑크톤의 직접노출 밀도차와 분비화학물질(infochemical)농도차에 의존하여 증가 혹은 변화될수 있는 가능성이 있는 것으로 나타났으며, 부영양호에서 독성 남조 번성 조절시, 이러한 가능성을 고려하여 생물조절이 이루어져야 할 것으로 보인다.

• Communications for Statistical Applications and Methods
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• 제30권2호
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• pp.163-178
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• 2023

GARCH-X(1, 1) model specifies that conditional variance follows an AR(1) process and includes a past exogenous variable. This study proposes a new class from that model by allowing a more general (non-linear) variance function to follow an AR(1) process. The functions applied to the variance equation include exponential, Tukey's ladder, and Yeo-Johnson transformations. In the framework of normal and student-t distributions for return errors, the empirical analysis focuses on two stock indices data in developed countries (FTSE100 and SP500) over the daily period from January 2000 to December 2020. This study uses 10-minute realized volatility as the exogenous component. The parameters of considered models are estimated using the adaptive random walk metropolis method in the Monte Carlo Markov chain algorithm and implemented in the Matlab program. The 95% highest posterior density intervals show that the three transformations are significant for the GARCHX(1, 1) model. In general, based on the Akaike information criterion, the GARCH-X(1, 1) model that has return errors with student-t distribution and variance transformed by Tukey's ladder function provides the best data fit. In forecasting value-at-risk with the 95% confidence level, the Christoffersen's independence test suggest that non-linear models is the most suitable for modeling return data, especially model with the Tukey's ladder transformation.