• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.71-76
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• 2009

This paper describes a statistical analysis method for predicting a coast fishing boat's effective horsepower. The EHP estimation method for small coast fishing boats was developed, based on a statistical regression analysis of model test results in a circulating water channel. The statistical regression formula of a fishing boat's effective horsepower is determined from the regression analysis of the resistance test results for 15 actual coast fishing boats. This method was applied to the effective horsepower prediction of a G/T 4 ton class coast fishing boat. From the estimation of the effective horsepower using this regression formula and the experimental model test of the G/T 4 ton class coast fishing boat, the estimation accuracy was verified under 10 percent of the design speed. However, the effective horsepower prediction method for coast fishing boats using the regression formula will be used at the initial design and hull-form development stage.

• 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.

• The Korean Journal of Applied Statistics
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• v.32 no.3
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• pp.331-348
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• 2019

Understanding the tumor heterogeneity due to differences in the growth pattern of metastatic tumors and rate of change is important for understanding the sensitivity of tumor cells to drugs and finding appropriate therapies. It is often possible to test for differences in population means using t-test or ANOVA when the group of N samples is distinct. However, these statistical methods can not be used unless the groups are distinguished as the data covered in this paper. Statistical methods have been studied to test heterogeneity between samples. The minimum combination t-test method is one of them. In this paper, we propose a maximum combinatorial t-test method that takes into account combinations that bisect data at different ratios. Also we propose a method based on the idea that examining the heterogeneity of a sample is equivalent to testing whether the number of optimal clusters is one in the cluster analysis. We verified that the proposed methods, maximum combination t-test method and gap statistic, have better type-I error and power than the previously proposed method based on simulation study and obtained the results through real data analysis.

• Journal of the Korean Geotechnical Society
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• v.25 no.2
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• pp.17-24
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• 2009

Undrained shear strength is estimated from laboratory tests generally, but the very soft or fluid material is generally incompatible with the test setup. In-situ methods require test to be accomplished at discrete time intervals, which does not provide a method to predict strength increment as a function of time for an ongoing project. Therefore, correlation between slump test value and undrained shear strength was derived through the regression analysis of slump test and laboratory vane shear test results. For the reliability of derived correlation equation statistical analysis using the t-distribution was performed and the comparison between the results of in-situ test and laboratory experiments demonstrated the applicability of the derived correlation.

• 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.

• Journal of Periodontal and Implant Science
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• v.30 no.3
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• pp.699-707
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• 2000

The purpose of this study was to analyze the statistical errors of articles in the Journal of Korean Academy of Periodontology from 1973 to 1999. Of the 662 articles examined, 263 were included which analyzed the data. They were classified into 2 groups with time lapse; group 1: 1973∼1989, group 2: 1990∼1999. Authors made checklists for analyzing the data and detecting the errors and analyzed them with professional statistician. The results were as follows: 1. Of 263 atricles which applied statistical method, 40(19.3%) was in group 1, 223(49.0%) in group2. 2. In the number of statistical method applied, 170(64.6%) were analyzed with 1 statistical method, 73(27.8%) with 2 methods, 18(6.8%) with 3 methods, and 2(0.8%) with 4 methods 3. The number of statistical methods applied was 14, and they were applied in order of 119 of ANOVA, 72 of Student t-test, 63 of Paired t-test, 36 of CORRELATION, and 21 of Mann- Whitney U test. 4. In 87(33.1%) of 263 articles and in 18 error items, statistical errors were found out. In group I, 9 items (55%) of error were found out, and were in order of 5 of Student t-test instead of Paired t-test, and 4 of unnecessary statistical analysis. In group II, 16 items (29.1%) of error were found out, and were in order of 22 of Student t-test instead of Paired t-test, 7 of no multiple comparison test after ANOVA, 6 of Student t-test instead of ANOVA, 6 of unnecessary statistical analysis, and 5 of ANOVA instead of Paired t-test. In conclusion, the results noted that statistical analyses were increased, but statistical errors were decreased with time. But authors suggest that researchers should refer to standard statistical texts and seek advice from professional statisticians to avoid the statistical errors.

• Corrosion Science and Technology
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• v.18 no.6
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• pp.292-299
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• 2019

The hull material of a high-speed ship may cause erosion damage from fluid impact. When physical erosion and electrochemical corrosion combine, erosion corrosion damage occurs. The aluminum ship is vulnerable to erosion corrosion because it can be operated at high speed. Thus, in this study, Al5052-O and Al6061-T6 aluminum alloys for the marine environment were selected as experimental materials. The erosion corrosion resistance of Al5052-O and Al6061-T6 aluminum alloys in seawater was investigated by an erosion test and potentiodynamic polarization test at the various flow rate (0 m/s, 5 m/s, 10 m/s, 15 m/s, 20 m/s). Erosion corrosion characteristics were evaluated by surface analysis, 3D analysis, SEM analysis, and the Tafel extrapolation method. The results of surface damage analysis after the erosion test showed that Al6061-T6 presented better erosion resistance than Al5052-O. The results of the potentiodynamic polarization test at the various flow rate, corrosion current density by Tafel extrapolation presented lower values of Al6061-T6 than Al5052-O. Al5052-O showed more surface damage than Al6061-T6 at all flow rates. Consequently, Al6061-T6 presented better erosion corrosion resistance than Al5052-O. The results of this study are valuable data for selecting hull material for an aluminum alloy vessel.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.207-208
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• 2019

Currently, as the public interest for environmental issues has grown rapidly, the needs for G-SEED have also increased. However, as investment according to eco-friendly elements is inevitable to receive G-SEED certification, it is necessary to find out whether or not the sales price of apartments have increased compared to investment costs. Therefore, the objective of this study is to analyze the sales price of apartments according to G-SEED by using T-test. To achieve the objective, First, variables affecting on the sales price of apartments are selected. Second, the data are collected by using GIS(Geographic Information System). Third, after testing the normality, a comparison analysis is conducted on the sales price between G-SEED certified and non-certified apartments by using T-test. As a result, it is concluded that G-SEED certified apartments are more expensive than non-certified apartments. In the future, these findings can be utilized to develop of apartments price calculation model based on the G-SEED.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.546-549
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• 2004

The T-50/A-50 Golden Eagle was developed for a supersonic trainer and light combat aircraft. At the design stage, vibration control plans were established and applied. For cockpit vibration, crew comfort vibration level was defined by the requirement of MIL-A-8892. It is found that the T-50/A-50 meets the requirement of cockpit vibration from the flight test data analysis. This paper contains the results of cockpit vibration analysis using the flight test data and the results of human vibration analysis lot the pilot inside aircraft. The human vibration level of pilot is increased as dynamic pressure is increased and at the specific high dynamic pressure, the ride comfort indicates 'a little uncomfortable'. Overall analysis results show that the vibration level of T-50/A-50 cockpit is tolerable and not critical for pilot's comfort.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.588-595
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• 2014

In this paper, analysis of the vibration Characteristic for the Mine Detectable Test Platform is described. The test platform system is the multi-sensor mine detectable vehicle. This multi-sensor mine detectable unit is more efficient detection performance than other conventional methods. The test platform system has five subsystems, the UWB(Ultra Wide Band) sensor scanner, the MD(Metal Detector) sensor scanner, the neutron sensor scanner, and the detectable vehicle. We perform the vibration tests for the test platform and analyze the vibration characteristic, such as the max displacement, the max deformation and the max Von-Misses Stress.