• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1109-1114
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• 2008

To investigate the effect of sample size on coefficient of consolidation of non-homogeneous soil, the result of a large size consolidation test using a huge undisturbed sample with $1200mm(D){\times}2000mm(H)$ in dimension is compared with that of oedometer test using undisturbed small sample. In addition, test results are compared with those of same test using remold sample. Experimental results show that, due to the lump of sand/silt was mixed in sample, the coefficient of consolidation of undisturbed samples have a difference for each tests. Whereas, the difference of coefficient of consolidation between remolded large and small samples is not found. Because sample size affects the test results, sample must be carefully selected for non-homogeneous soil.

• Journal of the Korea Society for Simulation
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• v.1 no.1
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• pp.77-86
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• 1992

In this paper, we study validation test methods of DEVSA(Descrete Event system Specification) models using SPN(Stochastic Petri Net) models. We discuss conventional validation test methods, by which DEVS models can be transformed to SPN models, by reviewing the features of DEVS model. Based on the model transformation method, we define a new homogeneous function for validation test and suggest a new validation test method of DEVS models using the property of SPN models and the new homogeneous function.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.575-578
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• 2007

The objective of this study is to analyze the regionalization of point rainfall by statistical methods for regional frequency analysis of the rainfall. The rainfall data used in this study are annual maximum rainfall at 57 stations during the period of more than 30 years for 12 durations(10min, 1, 2, 3, 4, 5, 6, 8, 10, 12, 18, 24hr) in Korea. The Mann-Whitney U test, Kruskal-Wallis one-way analysis of variance of nonparametric test the principal component and the cluster analysis have been performed to analyze the regionalization of rainfall. The results of this study are as follows; (1) The region which hydrological homogeneous is accepted does not exist for whole duration in Korea. (2) The result of nonpametric test shows that hydrological homogeneous regions of point rainfall are divided by 5 regions. (3) In case of cluster analysis hydrological homogeneous regions of point rainfall are divided by 6 regions and 4 other areas.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.73-76
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• 1999

Superconductors are dissipative when exposed to time-varying magnetic fields. To analyze the AC characteristics of the superconductor, one usually needs to know magnetization curves of it. A good magnetization curves can be obtained only in a homogeneous magnetic field. In this paper, we report the fabrication and test results of a homogeneous magnet, which aims to give background magnetic fields for the superconductor.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.45-48
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• 2002

In this paper, we propose an iris recognition system using Homogeneous Texture descriptor of MPEG-7 standard. The texture of iris is generally used in iris recognition system. We segment the pupil with Hough transform and the boundary of iris with it's gray level difference between the white of the eye. To extract Homogeneous Texture descriptor, this iris image is transformed into polar coordinates. The extracted descriptor is then compared with the reference in DB. If their distance is larger than threshold, they are recognized as different iris. Test results will show that Homogeneous Texture descriptor can be a good measure for iris recognition system.

• Journal of IKEEE
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• v.7 no.2 s.13
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• pp.218-222
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• 2003

Even if using the standard field test which radiation of electric wave and measurement test equipment there are difficult thing that building test equipment. so, we can use the substitution test field. In this paper, for optimization analysis for homogeneous field structure of GTEM-CELL (Giga hertz Transverse Electro Magnetic Cell) that calculate electromagnetic field characteristic for variable of each structure and characteristic impedance inner conductor.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.32-42
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• 1998

Lean burn gasoline engine is recognized as a promising way to meet better fuel economy. Lean burn engine is classified into port injection and direct injection(DI), DI is more active technique for improving fuel economy with ultra-lean operation, Nowadays, port injected lean burn engine has been produced by many Japan maker. Also, DI engine is also possible for production owing to improvement in control technique of spray, flow air fuel ratio. DI engine uses either homogeneous stoichiometric mixture or stratified mixture by controlling injection timing to be early or late respectively. HM(homogeneous mixture) is worse than SM(stratified mixture) in view of ultra-lean operation in partical load and Nox reducion by using EGR control. But, HM has advanteges in cold starting and emission reduction during transient operation, This paper describes experimental variables and bench test results of HM GDI engine.

• Korean Journal of Metals and Materials
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• v.47 no.11
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• pp.759-772
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• 2009

Amorphous alloys, in addition to being promising materials for a variety of practical applications, provide an excellent test bed for evaluating our understanding of the underlying physics on deformation in amorphous solids. Like many amorphous materials, amorphous alloys can exhibit either homogeneous or inhomogeneous deformation depending on the stress level. The mode of deformation has a strong influence on whether the material behavior is classified as ductile or brittle. It was observed that the characteristics of these deformations are largely dependent on the atomic-scale structures of the alloys and determine the amount of the plastic deformation prior to failure. In this study, the structural features that control the homogeneous deformation of amorphous alloys are outlined on the basis on experiments and molecular dynamics simulations.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.182-189
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• 2004

The application of adhesively bonded components is increasing in various industries such as automobile, aircraft, IC packages, and soldering techniques. In spite of such wide application in adhesively bonded components, nondestructive test techniques applying to adhesively bonded components have not been clearly established yet. In this paper, characteristics of ultrasonic test on interfaces of adhesively bonded components have been investigated by calculating transmission coefficient theoretically and experimentally. From the experimental results, the optimum conditions to establish frequencies for adhesively bonded homogeneous and dissimilar components are 4∼6 MHz and 2∼4 MHz, respectively.

• Communications for Statistical Applications and Methods
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• v.13 no.2
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• pp.429-440
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• 2006

In statistical computing, it is often for researchers to need the distribution of a weighted sum of noncentral chi-square variables. In this case, it is very limited to know its exact distribution. There are many works to contribute to this topic, e.g. Imhof (1961) and Solomon-Stephens (1977). Imhof's method gives good approximation to the true distribution, but it is not easy to apply even though we consider the development of computer technology Solomon-Stephens's three moment chi-square approximation is relatively easy and accurate to apply. However, they skipped many details, and their simulation is limited to a weighed sum of central chi-square random variables. This paper gives details on Solomon-Stephens's method. We also extend their simulation to the weighted sum of non-central chi-square distribution. We evaluated approximated powers for homogeneous test and compared them with the true powers. Solomon-Stephens's method shows very good approximation for the case.