• Journal of Aerospace System Engineering
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• v.10 no.1
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• pp.29-34
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• 2016

Flutter wind-tunnel test is an expensive and complicated process. Also, the test model may has discrepancy in the structural characteristics when compared to those of the real model. "Dry Wind-Tunnel" (DWT) is an innovative testing system which consists of the ground vibration test (GVT) hardware system and software which computationally can be operated and feedback in real-time to yield rapidly the unsteady aerodynamic forces. In this paper, we study on the aerodynamic forces of DWT system to feedback in time domain. The aerodynamic forces in the reduced-frequency domain are approximated by Minimum-state approximation. And we present a state-space equation of the aerodynamic forces. With the two simulation model, we compare the results of the flutter analysis.

• Journal of the Korean Arthroscopy Society
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• v.1 no.1
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• pp.26-30
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• 1997

Recently, the incidence of anterior cruciate ligament injury is rapidly increasing because many young Korean are actively participating in sports activities including basketball, skiing and soccer. Sometimes acute ACL injuries arc misdiagnosed as sprain because of pain and muscle spasm. An accurate physical examination and careful history taking are very important to diagnose the ACL injuries. Therefore author described the skill of history taking and the technique of physical examination to diagnose ACL injuries. The most sensitive test is the Lachman's test, which is performed with the knee in 200 of flexion, the femur stabilized with full flexed examiner's knee placed behind patient's distal thigh and one hand of examiner, and the proximal tibia grasped with the other. The pivot shift test is a passive motion test that attempts to subluxate the tibia anteriorly, then have it reduce rapidly. The pivot shift test is very sensitive test to diagnose the chronic ACL injuries.

• Korean Journal of Oriental Medicine
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• v.2 no.1
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• pp.129-145
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• 1996

According to the Medical Product Safety Administration Guidelines for safety assessment guinea pigs, mice and rats were used for antigenicity test, rabbits for pyrogenic test and hymolytic test. The results were summarized as follows; 1. The antigenicity test of Red-ginseng radix extract solution for herb-acupuncture did not show any anaphylatic shock but produced IgE in high dose group. 2. The result of the pyrogen test of Red-ginseng radix extract solution for herb-acupuncture was negative. 3. The result of the hemolytic test of Red-ginseng radix extract solution for herb-acupuncture were negative in low and middle dose group but was positive in high dose group.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.35-40
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• 2004

The high-speed wind tunnel test of rocket model was performed to investigate the effect of skirt configuration on aerodynamic load characteristics of nozzle. Test parameters were the length and diffusing angle of skirt. Test results showed that the gimbals actuator power could be reduced to 1/10 of that without skirt. The normalized test result was proposed to be used as database for skirt design.

• International Journal of Reliability and Applications
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• v.15 no.1
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• pp.11-22
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• 2014

New classes of life distributions called new better (worse) than used at age $t_0$ in Laplace transform order, NBUL- $t_0$(NWUL - $t_0$) are introduced. For the classes NBUL - $t_0$(NWUL - $t_0$), preservation under convolution, mixture, mixing and the homogeneous Poisson shock model are studied. In the sequel, we obtain a test for $H_0$ : F is exponential versus $H_1$ : F is NBUL - $t_0$ and not exponential. The critical values and the powers of this test are calculated to assess the performance of the test. It is shown that the proposed test has high efficiencies for some commonly used distributions in reliability. Sets of real data are used as examples to elucidate the use of the proposed test for practical problems.

• International Journal of Reliability and Applications
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• v.15 no.1
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• pp.1-9
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• 2014

Let X and $X_t$ denote the lifetime and the residual life at age t, respectively. X is said to be a NBUL (new better than used in Laplace transform order) random variable if $X_t$ is smaller than X in Laplace order, i.e., $X_t{\leq}_{LT}X$. We propose a new test statistics for testing exponentiality versus NBUL class of life distribution. The tests by Hollender and Proschan (1975) and the generalized Hollender and Proschan test by Ains and Mitra (2011) are considered as special cases of the our of test statistics. Our proposed test statistics is simple, consistent and asymptotically normal. Efficiency and powers of the test statistics for some commonly used distributions in reliability are discussed. Finally, real examples are presented to illustrate the theoretical results.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.323-326
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• 2005

Uniaxial tension test of Glass Fiber Reinforced Polymer (GFRP) bar reinforced concrete prisms was performed. The objective was to investigate the adequate cover thickness of the GFRP rebars. The tension stiffening effect of GFRP bar reinforced concrete was also studied. The test variables included rebar types (conventional steel rebar and two different GFRP rebars) and cover thicknesses (five different cover thicknesses ranging between 1-3db). Normal strength concrete was used. Cracking patterns on concrete surface and cracking loads were careful1y observed during the direct tensile test. The test results indicated that the adequate cover thickness of the GFRP rebars may even be larger than that of the steel rebars and that the cover thickness of 2db commonly specified for the GFRP rebars may not be large enough. The tension stiffening effect of the GFRP rebars was also quantified and documented from the test results.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.1
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• pp.25-28
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• 2011

In this paper, we study some properties of condition for fuzzy data, agrement index by ratio of area and the uniformly most powerful fuzzy test of hypothesis. Also, we suggest a confidence bound for uniformly most powerful fuzzy test. For illustration, we take the most powerful critical fuzzy region from exponential distribution by likelihood ratio and test the hypothesis of ${\chi}^2$-distribution by agreement index.

• Journal of Power Electronics
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• v.6 no.1
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• pp.1-7
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• 2006

This paper is a record of the study on a high efficiency and high power chopper based on the new soft switching method QRAS (Quasi~resonant Regenerating Active Snubber) designed for a Fuel Cell Electric Vehicle (FCEV). This power chopper is basically proposed for 25kHz soft switching. To confirm the practicality and effectiveness of the converter, the fabrication of a prototype-model using IGBTs was completed. Additionally, a 8kW rating test, a light load test, a current discontinuous mode test and a stable operation resonance test was completed. The circuit geometry, the basic operation, and the 8kW one-tenth-prototype test results are reported with a $97.5\%$ efficiency measurement.

• The Journal of Fisheries Business Administration
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• v.44 no.1
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• pp.71-79
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• 2013

This study is aimed to estimate market integration of wild caught fish species on the Korean market, using both multivariate and bivariate cointegration analysis. For the analysis of market integration between wild caught fish species, major four fish species those are most popular fish in the market and caught by the large purse seine fishery-chub mackerel, jack mackerel, hairtail and spanish mackerel-were selected as analytical target fish species. And their real monthly price data from January 2000 to December 2011 were used in the analysis. The results of the multivariate cointegration test for four wild caught fish species showed that there would be long-term equilibrium relationships among prices of four wild caught fish species, and consequently, the markets for wild caught fish species were estimated to be integrated. The results of exclusion test and bivariate cointegration test also supported that there would be a clear evidence to suggest that all target wild caught fish species were cointegrated each other.