• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.67-74
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• 2018

The verification for the design limit margin of the power device for the information communication and surveillance systems using HALT(Highly Accelerated Life Test) reliability test is described. The HALT reliability test performs with a step stress method which change condition until the marginal step in a design and development phase. The HALT test methods are the low temperature(cold) step stress test, the high temperature(hot) step stress test, the thermal shock cyclic stess test, and the high temperature destruct limit(hot DL) step stress test. The power device is checked the operating performance during the test. In this paper, the HALT was performed to find out the design limit margin of the power device.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.375-382
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• 2003

This study, Using Pusan clay, examined a relationship between Dynamic and Static Liquid Tests. The Static Liquid Tests wow carried out based on BS and JIS. The results of the study are summarized as follows. (1) The result of the Dynamic Liquid Limit Test showed that the liquid limit values of air-dried soil were greater than those of oven-dried soil by 4%~15% (2) The liquid limit value of the Static Liquid Limit Test was greater than that of the Dynamic Liquid Limit Test by 2%~9%. The following equations show the relationship between the two values WL,Fall(JIS) = 0.961ㆍWL,Cas. + 4.209 WL,Fall(BS) = 0.969ㆍWL,Cas + 5.024 (3) The liquid limit value of BS was greater than that of JIS by 1%~6%. The following equation shows the relationship between the two values.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.2
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• pp.121-129
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• 1993

Plane strain punch stretching test (PSST) was developed to evaluate stamping formability of sheet materials. In this test, the rectangular specimen of sheet material is uniformly stretched up to fracture by raising a specially designed punch to certainly assure plane strain stretching deformation along the longitudinal direction of the specimen. The stamping formability was evaluated by limit punch height(LPH) in plane strain punch stretching test compared to limit dome height(LDH) in hemispherical punch stretching test. LPH-value in PSST well ranks the stamping formability of various material and correlates with press performance. Moreover by using ultrasonic thickness gauge the plane strain intercept-limit plane strain(FLCo)-in forming limit curve can be accurately determined from thickness measurement around the fracture area. The FLCo derived from thickness measurement well correlates with the results from circle grid analysis for the deformed circle grid marked on the surface of the specimen.

• The Journal of Korean Physical Therapy
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• v.25 no.4
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• pp.180-186
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• 2013

Purpose: This study was to find a correlation between the bilateral reciprocal leg press test and a the balance in chronic stroke patients. Methods: Eighteen patients performed an isokinetic leg press test consisting of a bilateral reciprocal and unilateral mode. Following the isokinetic leg press testing, subjects performed the balance test: Berg Balance Scale (BBS), Timed Up & Go (TUG) test, and stability limit. Pearson product moment correlation coefficients were used to determine the correlation between the mean score of the isokinetic leg press test, balance test in both affected and non-affected side. Results: This study indicated a significant correlation between the bilateral reciprocal leg press test and stability limit. There were significant correlation between non-affected side bilateral leg press(NBL) and BBS (r=0.501), affected side bilateral leg press (ABL) and non-affected side stability limit(NS) (r=0.614), ABL and total stability limit (TS) (r=0.493), NBL and affected side stability limit(AS) (r=0.480), NBL and NS (r=0.560), NBL and TS (r=0.563), among the patients. Conclusion: Measurement of the lower extremity strength using the bilateral reciprocal leg press test can be used as an evaluating tool of the balance test.

• Journal of the Korean Geotechnical Society
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• v.33 no.3
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• pp.5-15
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• 2017

In this study, the liquid and plastic limit tests were conducted on Paju clay with Casagarande method (dynamic) and the fall cone test method (static) to find out the effects of test methods and testers on their values. Six testers, who already have the experience of test, participated. As a results of liquid limit tests, the fall cone test method showed 4% smaller liquid limit compared to the value determined by Casagrande method. As the number of tests increased, the fall cone test method showed less variation between testers and the variation range of level of proficiency was also more stable. In the case of one point method, the liquid limit determined by the fall cone test method varied with smaller range compared to the Casagrande. Consequently, the fall cone test provided more stable liquid limit value than that of Casagrande method. For the results of plastic limit tests, there were no difference between Casagrande method and the fall cone test unlike liquid limit test results. In other words, both methods showed that plastic limit reached the average value as the number of tests increased, and the tendency level of proficiency also showed to get better.

• Transactions of Materials Processing
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• v.15 no.6 s.87
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• pp.467-472
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• 2006

The forming limit diagram of tube is required for the part design and the formability analysis of tube hydroforming. The finite element analyses of simple bulge test were done to obtain the various strain combinations on FLC. The finite element analysis results were shown that the bursting at various strain combinations could be induced by simple bulge test. The experiment oi tube bulge test was carried out according to the test condition that obtained from finite element analysis and the left hand side of forming limit diagram was built.

• Journal of Korean Society for Quality Management
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• v.35 no.3
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• pp.107-117
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• 2007

The fatigue has been considered the most failure mode of metal, ceramic, and composite materials. In this paper, numerical experiments to asses the usefulness of two Dixon's methods(small and large samples) and 14 S-N methods on assumptions of lognormal fatigue limit distribution under RFL(Random Fatigue Limit) model are conducted for staircase(or up-and-down) test and compared by MSE(Mean Squared Error) and bias for estimates of mean log-fatigue limit. Also, guidelines for staircase test plans to choose initial stress level and step size are recommended from numerical experiments including sensitivity analyses. In addition, the parametric bootstrap method to construct a confidence interval for the mean of log-fatigue limit by the percentile method using a transition probability matrix of Markov chain is presented and illustrated with an example.

• Communications for Statistical Applications and Methods
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• v.21 no.6
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• pp.539-559
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• 2014

We derive the exact distribution of summation for random samples from uniform distribution and then compare the exact distribution with the approximated normal distribution obtained by the central limit theorem. To check the similarity between two distributions, we consider five existing normality tests based on the difference between the target normal distribution and empirical distribution: Anderson-Darling test, Kolmogorov-Smirnov test, Cramer-von Mises test, Shapiro-Wilk test and Shaprio-Francia test. For the purpose of comparison, those normality tests are applied to the simulated data. It can sometimes be difficult to derive an exact distribution. Thus, we try two different transformations to find out which transform is easier to get the exact distribution in terms of calculation complexity. We compare two transformations and comment on the advantages and disadvantages for each transformation.

• Journal of Korean Medicine for Obesity Research
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• v.10 no.1
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• pp.29-40
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• 2010

Objective The aim of this study was to evaluate the influence of Gamitaeeumjowi-tang(GTT) prescribed by doctors of korean(KMD) medicine on liver function. Methods For this single-center, prospective, observational study, we enrolled patients who wished to take GTT prescribed by KMD for losing weight. sixty(60) patients took GTT for 33.8 days and completed questionnaires. Liver function tests(LFTs) were performed bofore(first test) and after each GTT treatment(finish test). For LFT, T-bil, ALP, AST, ALT were measured. Result There were no significant changes in LFT data between the first and finish tests. At first test, levels of test seven(7) patients were more than twice of normal range of upper limit, levels of eight(8) patients were more than normal range of upper limit, less than twice of normal range of upper limit. At last test, levels of nine(9) patients were more than normal range of upper limit, less than twice of normal range of upper limit. Conclusion The current study showed that ingestion of GTT prescribed by KMD did not increase the frequency of abnormal LFTs, at least in the short term.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.68-79
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• 2018

An examination of the characteristics of the ground material in is very important in a ground investigation. Casagrande classified soil using the material properties of soils. The liquid-plastic limit test is useful for obtaining basic information of soil, and is an effective method for classifying silt and clay, as well as the material properties, such as shear strength, shrinkage, and expansion. Unlike the liquid limit test, the plasticity limit test is due to the ambiguity of the test procedure. Many geotechnical engineers and scholars have questioned the test results. In this study, a new plasticity limit method was used to compare with the thread rolling method with kaolinite, ilite and bentonite at a certain ratio, and samples were collected from the west coast of Korea. As a result of the comparison, the test value of the new test method showed high reproducibility because the error range of the test value of the conventional thread rolling test was only 10% but the error range of the new test values decreased to 2%. The difference in the slope of the existing plasticity test values was 0.1519 ~ 0.1925, and the results of the test were similar or coincided with each other. Aone - point method was proposed to make it easier to apply the new test method.