• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.258-261
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• 2006

The structure of small launch vehicle can be divided into engine section and payload section. This paper introduces modal test of the payload section of small launch vehicle which is composed to satellite, PLA (Payload Adapter), VEB (Vehicle Equipment Bay), KMS (Kick Motor Support) and KM (Kick Motor). From this test, dynamic properties of the 2nd stage structure of small launch vehicle can be obtained. In this test, to simulate free-free boundary condition, test object was hung by 4 bungee cords and excited by using impact hammer Modal test data are analyzed by using TDAS(Test Data Analysis Software). As the result, modal parameters and mode shapes below 100Hz of the 2nd stage of small launch vehicle were identified.

• Journal of information and communication convergence engineering
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• v.3 no.1
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• pp.28-32
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• 2005

In this paper, we propose a novel test method to effectively detect hard and soft faults in CMOS 2-stage op-amps. The proposed method uses a very high frequency sinusoidal signal that exceeds unit gain bandwidth to maximize the fault effects. Since the proposed test method doesn't require any complex algorithms to generate the test pattern and uses only a single test pattern to detect all target faults, therefore test costs can be much reduced. The area overhead is also very small because the CUT is converted to a unit gain amplifier. Using HSPICE simulation, the results indicated a high degree of fault coverage for hard and soft faults in CMOS 2-stage op-amps. To verify this proposed method, we fabricated a CMOS op-amp that contained various short and open faults through the Hyundai 0.65-um 2-poly 2-metal CMOS process. Experimental results for the fabricated chip have shown that the proposed test method can effectively detect hard and soft faults in CMOS op-amps.

• Journal of Pharmacopuncture
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• v.19 no.3
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• pp.213-224
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• 2016

Objectives: Ginseng Rh2+ is enzyme-treated ginseng extract containing high amounts of converted ginsenosides, such as compound k, Rh2, Rg3, which have potent anticancer activity. We conducted general and genetic toxicity tests to evaluate the safety of ginseng Rh2+. Methods: An acute oral toxicity test was performed at a high-level dose of 4,000 mg/kg/day in Sprague-Dawley (SD) rats. A 14-day range-finding study was also conducted to set dose levels for the 90-day study. A subchronic 90-day toxicity study was performed at dose levels of 1,000 and 2,000 mg/kg/day to investigate the no-observed-adverse-effect level (NOAEL) of ginseng Rh2+ and target organs. To identify the mutagenic potential of ginseng Rh2+, we conducted a bacterial reverse mutation test (Ames test) using amino-acid-requiring strains of Salmonella typhimurium and Escherichia coli (E. coli), a chromosome aberration test with Chinese hamster lung (CHL) cells, and an in vivo micronucleus test using ICR mice bone marrow as recommended by the Korean Ministry of Food and Drug Safety. Results: According to the results of the acute oral toxicity study, the approximate lethal dose (ALD) of ginseng Rh2+ was estimated to be higher than 4,000 mg/kg. For the 90-day study, no toxicological effect of ginseng Rh2+ was observed in body-weight changes, food consumption, clinical signs, organ weights, histopathology, ophthalmology, and clinical pathology. The NOAEL of ginseng Rh2+ was established to be 2,000 mg/kg/day, and no target organ was found in this test. In addition, no evidence of mutagenicity was found either on the in vitro genotoxicity tests, including the Ames test and the chromosome aberration test, or on the in vivo in mice bone marrow micronucleus test. Conclusion: On the basis of our findings, ginseng Rh2+ is a non-toxic material with no genotoxicity. We expect that ginseng Rh2+ may be used as a novel adjuvant anticancer agent that is safe for long-term administration.

• 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)).

• Journal of Aerospace System Engineering
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• v.5 no.2
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• pp.1-7
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• 2011

On this study, applicable aircraft pitot-static system airworthiness requirements and flight test techniques for PEC(Position Error Correction) to KAS Part 23 airworthiness standards are introduced. Also, pros and cons, applicable test conditions, test procedures and required test parameters of each flight test techniques are reviewed on this study.

• 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.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.55-63
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• 2007

STSAT-2 (Science & Technology SATellite-2) is a Korea micro-satellite which will be launched at NARO Space center in Koheung, Korea. Launch vehicle for STSAT-2 is KSLV-1 (Korea Space Launch Vehicle-1) which is the first development in Korea space launch vehicle program. Starting development in 2002 EM(Engineering Model), PFM(Proto-Flight Model), and FM(Flight Model) were developed completely. Electrical functional test, space environmental test, and launch vehicle environmental test on system level are performed for testing those development models. In this paper we report the results of STSAT-2 PFM space environmental test and launch vehicle environmental test which is successfully completed.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.377-384
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• 2008

In the bi-directional pile load test (BD PLT) for pile load test of Mega foundation, loading capacity specification were not specified exactly. Therefore there are so many confusions and variations of maximum 2 times in loading capacity are come out. In this study, specifications of bi-directional pile load test (BD PLT) were considered. Based on cases of the bi-directional pile load test performed in domestic areas, maximum equivalent test load, test load increasing ratio and sufficiency ratio of design load were analyzed. It can be known that the loading capacity specification of bi-directional pile load test must be defined as 1-directional test load that is established as more than 2 times of design load.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.203-208
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• 2016

In this study, to clarify the differences rebar corrosion beginning, through the actual corrosion accelerated test in corrosion time and laboratory test chamber of the structure of the marine environment results in both environments, it is an object of correlation coefficient derived. The accelerated corrosion test was carried out by two case, I.e., one is $20^{\circ}C$ of low temperaure codition(case 1), and the other is $65^{\circ}C$ of high temperaute codition(case 2). Whether corroions occurs, it was measures using half-cell potential method. The results indicated that case 2 is to acclerate the corrosion of rebar about 1.7~1.8 times as compared with case 1, thenthe corrosion of rebar embadded in concrete occurred according to the order of OPC60, FA, BS, OPC35. Correlation coefficient between acclerated corrosion test and long-term exposure test, case 1 is 2.45 to 2.94, and case 2 is 4.37~4.99.

• The Korean Journal of Applied Statistics
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• v.8 no.2
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• pp.87-97
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• 1995

When there is no main effcts or only one main effect in a $2 \times 2$ factorial design, Type I error rates and power for the rank transformed F test (FR test) for interaction are nearly equal to those of the classical F test. However the power of FR test is quite superior under the exponential distribution rather than the of FR test is quite superior under the exponential distribution rather than the normal distribution. Meanwhile when both main effects are in the model, Type I error rates of FR test, compared with those of F test, decrease as the effect size increases and are dependent on the fashion in which main effects are constructed. In addition, the power of FR test increases as the effect size and the sample size increase and is highly dependent on the manner in which main effects are constructed and the type of population distribution.