• Journal of the Korean Data and Information Science Society
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• v.25 no.1
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• pp.1-10
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• 2014

In this paper, we study approximations of the ruin probability in a continuous time surplus process. First, we introduce the well-known approximation formulas of the ruin probability such as Cram$\acute{e}$r, Tijms' and De Vylder's methods. We, then, suggest new approximation formulas of two types, which improve the existing approximation formulas. One is Cram$\acute{e}$r and Tijms' type which makes use of the moment generating function of distribution of a claim size and the other is De Vylder's type which makes use of the surplus process with exponential claims. Finally, we compare, by illustrating numerical examples, the newly suggested approximation formulas with the existing approximation formulas of the ruin probability.

• Journal of Advanced Navigation Technology
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• v.15 no.2
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• pp.234-240
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• 2011

In this paper, the performances of Cram$\acute{e}$r-Rao Lower Bound (CRLB) with Frequency Difference of Arrival (FDOA) measurements for Unmanned Aerial Vehicle (UAV) tracking are investigated. We focus on two cases: the influence on CRLB with FDOA measurements collected by time, and random distribution of Ground Stations (GSs). We derived the performance by gauging the size of CRLB through Complementary Cumulative Distribution Function (CCDF). From the simulation results, broader distribution of GSs and FDOA measurements by longer time bring about better performance.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.53-56
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• 2007

Computer simulation of microstructure evolution during hot forging process is of great interest in recent years. Recrystallization model and grain growth model which use a phenomenological approach were summarized. For the waspaloy, upsetting process and cogging process were simulated using $DEFORM^{TM}$ and the change in grain size were investigated in each deformation procedure.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.4
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• pp.43-52
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• 2005

It is known in some literatures that the B value is not equal to unity in saturated soil when effective stress is given, in which the B Value is the ratio of measured excess pore water pressure and isometric loading pressure. In this study the B value was measured on various effective stresses and on various incremental loading stresses in various grain size of specimens with saturated sand. The test results showed that the B value was affected largely by grain size of sand in specimen and the amount of effective stress. There was the semi-logarithmic relationship between B value and effective stress, and also there was the linear relationship between the gradient of the former semi-logarithmic relationship and grain size of specimen.

• Korean Journal of Microbiology
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• v.35 no.3
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• pp.192-196
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• 1999

CHEF-PFGE(Contour-Clarnped Homogeneous Electric field- Pulsed Field Gel Electrophoresis) was used to identify electrophoretic karyotype for eight strains belonging to the Fzisoriuni section Liseolo. Chromosome numbers were nine to thirteen bands, ranging in size Cram 0.75 to 6.45 Mb. The total genome size was eslimated to range from 38.19 Mb to 43.12 Mb and numerous chromosome-length polymorphisms (CLPs) were observed. For the chromosome localizalion of the gene, 1GS sequence(2.6 Kb) of rDNA from F: moniliforme, chs-2 gene(2.8 Kb) and 4 - 3 gene(3.8 Kb) from Neuuospora cmssa were wed as probes.

• Archives of design research
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• v.19 no.6 s.68
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• pp.5-8
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• 2006

Inversion therapy has been used to relieve backpain, decrease pressure on the discs between vertebrae and stretch musdes as early as 400 BC. Gravity Guidance Inversion Table was introduced in 1960's and has been commercialized mostly for relieving backpain. in United States. But this machine needs to adjusted and possible sudden movement can cause severe injury to the users. In the 1990's, motor assisted inversion cram was introduced in Germany. But this inversion cram is too heavy and inconvenient to be used at home. In these days, the inversion machine become popular equipment in fitness clubs and health care places for relieving backpain as well as stretching muscles. And there is a growing need for home use version of motorized inversion machine. In this study, the motorized inversion machine was developed to be used for stretching exercise at home. The design became compact, simple and foldable as the results of adapting the wabble mechanism. And the machines are optimally designed by analyzing the torques applied to the machine by diverse physical size of users.

• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.26-32
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• 1990

Attempts were made to define the characteristics of microbial community as an indicator of Kimchi fermentation. Determination of communities was carried out by simple Gram-stain, followed by direct microcopic counts. In room-temperature $(15^{\circ}C)$ fermentation, microbial succession was occurred in the order of communities of Gram-positive bacteria, yeasts and Gram-negative bacteria. It was characteristic that Gram-positive bacterial community was developed during the production of lactic acid, yeasts community was developed to cause rancidity, and Gram-negative bacterial community was relevant to maceration (or softening) as well as rancidity. The fluctuation of apparent Gram-negative reaction group might be used as a criterion of death or aging of Gram-positive bacterial populations. In low-temperature fermentation $(5^{\circ}C)$, however, it was found that yeasts and Gram-negative bacterial communities did not developed but only Gram-positive bacterial community did. It follows from these results mentioned above that maturity of Kimchi depends on the development of Cram-positive bacterial community. Thus, the size and occurrence of microbial community are avaiable for an indicator of Kimchi fermentation, and also determination of community could be a useful method to predict the maturity.