• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.4
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• pp.439-450
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• 2023

In this study, the impact load resulting from collision with the fuel rods of surrogate spent nuclear fuel (SNF) assemblies was measured during a rolling test based on an analysis of the data from surrogate SNF-loaded sea transportation tests. Unfortunately, during the sea transportation tests, excessive rolling motion occurred on the ship during the test, causing the assemblies to slip and collide with the canister. Hence, we designed and conducted a separate test to simulate rolling in sea transportation to determine whether such impact loads can occur under normal conditions of SNF transport, with the test conditions for the fuel assembly to slide within the basket experimentally determined. Rolling tests were conducted while varying the rolling angle and frequency to determine the angles and frequencies at which the assemblies experienced slippage. The test results show that slippage of SNF assemblies can occur at angles of approximately 14° or greater because of rolling motion, which can generate impact loads. However, this result exceeds the conditions under which a vessel can depart for coastal navigation, thus deviating from the normal conditions required for SNF transport. Consequently, it is not necessary to consider such loads when evaluating the integrity of SNFs under normal transportation conditions.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.603-608
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• 1997

Studies on the second-order analysis of reinforced concrete columns have been chiefly dealt with symmetric section under uniaxial loading. In practical situations, however, columns are subjected to biaxial loadings. Therefore, for more accurate prediction of the behavior of concrete columns under biaxial loading, the interaction between bending moments of major and minor axes should be considered. Recently Kim & Lee proposed a numerical method of predicting the behavior of concrete columns under biaxial loading. In this paper, to investigate the behavior of concrete columns under biaxial loading and verify the validity of proposed method, a series of test were carried out for sixteen tied reinforced columns with 100${\times}$100mm square and 200${\times}$100mm rectangular sections under various loading conditions. The length of columns was 1,300mm and the concrete strength was 28MPa. The boundary conditions at the both ends were hinged and end eccentricities were equal(400mm). Proposed numerical analyses applied to the test piece were performed to predict behavior of concrete columns with square and rectangular sections under various loading conditions. Test results were also compared with those using the moment magnifier method in ACI code. The test results showed that the moment magnifier method is conservative.

• Journal of the Korean Statistical Society
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• v.32 no.2
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• pp.163-174
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• 2003

We propose a test for independence of bivariate censored data under univariate censorship. To do this, we first introduce a process defined by the difference between bivariate survival function estimator proposed by Lin and Ying (1993) and the product of the product-limit estimators (Kaplan and Meier, 1958) for the marginal survival functions, and derive its asymptotic properties under the null hypothesis of independence. We propose a Cramer-von Mises-type test procedure based on the process . We conduct simulation studies to investigate the finite-sample performance of the proposed test and illustrate the proposed test with a real example.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.2008-2014
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• 1999

IDDQ testing is an effective testing method to detect various physical defects occurred in CMOS circuits. In this paper, we consider intra-gate shorts within circuit under test and implement IDDQ test pattern generator to find test patterns which detect considered defects. In order to generate test patterns, gate test vectors which detect all intra-gate shorts have to be found by type of gates. Random test sets of 10,000 patterns are applied to circuit under test. If an applied pattern generates a required test vector of any gate, the pattern is saved as an available test pattern. When applied patterns generate all test vectors of all gats or 10,000 patterns are applied to circuit under test, procedure of test pattern generation is terminated. Experimental results for ISCAS'85 bench mark circuits show that its efficiency is more enhanced than that obtained by previously proposed methods.

• Communications for Statistical Applications and Methods
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• v.16 no.2
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• pp.325-334
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• 2009

In this research, we propose a nonparametric test procedure for the right censored and grouped data under the additive hazards model. For deriving the test statistics, we use the likelihood principle. Then we illustrate proposed test with an example and compare the performance with other procedure by obtaining empirical powers. Finally we discuss some interesting features concerning the proposed test.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.16 no.1
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• pp.1-10
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• 2020

This study proposed a simulated test method using ring specimen to evaluate the deformation and failure characteristics of pipe elbows under a large amplitude cyclic load. The validity of the test method was demonstrated by finite element (FE) analysis of pipe elbow and ring specimen under cyclic loads. The results showed that the proposed test method adequately simulates the distribution of circumferential strain at crown of pipe elbows where cracks occur under cyclic loads and presents the cyclic hardening behavior of pipe elbows. The parametric FE analysis showed that consistent simulated test results could be obtained when the test section of the ring specimen is longer than 1/2 of the inner diameter of the ring specimen and the radius of the inner loading jig is less than 1/4 of the inner diameter of the specimen.

• International Journal of Air-Conditioning and Refrigeration
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• v.15 no.4
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• pp.147-155
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• 2007

Mobile air conditioning systems work under widely changing operating conditions. To understand the system behavior under such dynamic conditions, a test facility that can impose transient loads as well as conducting dynamic measurements is needed. To test mobile air conditioning systems including their dynamic performance under various drive cycle patterns without using full scale vehicles in a wind tunnel, a new test facility, called "dynamic simulator," is described. It can replicate real vehicle operating conditions by interacting with the system being tested based on the measured system performance and subsequently adjusting the air properties returning to the test system based on the results of a numerical cabin model. A new dynamic simulator has been designed, constructed, and verified for performing dynamic tests. It was successful in controlling the temperature and relative humidity of the air returning to the test unit within ${\pm}0.7^{\circ}C$ and ${\pm}4%$ of their respective intended values. The verification test under the New European Driving Cycle demonstrated that detailed transient behavior of the mobile air conditioning system could be measured by using this dynamic simulator.

• Journal of Power System Engineering
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• v.16 no.3
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• pp.44-50
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• 2012

The reliability qualification test is essential in order to ensure the life time of the product under the normal operation conditions when a new product is developed. The reliability qualification test period has an important impact on the development time of new product. Therefore, some researches to reduce the test time of reliability qualification test have been actively studied. Generally, accelerated life test is well known as one method that can save the test time of the reliability qualification test. This test is conducted under the higher stress condition than normal condition. So we need to investigate what factor affects to the higher stress condition. This paper shows the relationship between the acceleration factor and reliability qualification test period. Especially, we focused on the method to obtain effective acceleration factors under the high temperature condition. Through some experiments for a refrigerator's compressor, we were able to confirm how to increase acceleration factors and how to reduce the reliability qualification test period with minimum samples.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.4
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• pp.287-292
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• 2011

To evaluate the pressure-resistant performance of underwater equipment, hyperbaric chamber test facility which can make the hydrostatic pressure is used. In this test, strain gage is generally applied to measure the strain of object under test is suitable for measuring a tiny deformation, but it can not measure a large deformation. Thus this paper suggests a method to estimate the over -order deformation of object under test by the image processing with the image acquired from underwater camera in the hydrostatic test. The main procedure of suggested method comprises the first step to find significant points by processing the image two dimensionally and the second step to estimate a deformation of object under test by tracking the motion of these points. If completing the remained research which is estimating the deformation and comparing it with a real one, it can be a method to measure the over -order deformation of object under test.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.2
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• pp.31-39
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• 2019

Cracked component analysis is needed for structural integrity analysis under seismic loading. Under large amplitude cyclic loading conditions, the change in material properties can be complex, depending on the magnitude of plastic strain. Therefore the cracked component analysis under cyclic loading should consider appropriate cyclic hardening model. This study introduces a procedure for determining an appropriate cyclic hardening model for cracked component analysis. The test material was nuclear-grade TP316 stainless steel. The material cyclic hardening was simulated using the Chaboche combined hardening model. The kinematic hardening model was determined from standard tensile test to cover the high and wide strain range. The isotropic hardening model was determined by simulating C(T) test under cyclic loading using ABAQUS debonding analysis. The suitability of the material hardening model was verified by comparing load-displacement curves of cyclic C(T) tests under different load ratios.