• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.155-157
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• 2004

Voltage control and stability problems are very important in the electric utility industry. But there is no voltage stability analysis program which has reliability as commercial program in domestic. We are developing a practical voltage stability analysis program. In this paper, we will study the existing commercial program and then discuss design of practical analysis tool.

• Communications of the Korean Mathematical Society
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• v.13 no.4
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• pp.913-931
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• 1998

Using invariant theory, new invariant cubature formulas over a unit cube are given by imposing a group structure on the formulas. Cools and Haegemans [Computing 40, 139-146 (1988)] constructed invariant cubature formulas over a unit square. Since there exists a problem in directly extending their ideas over the unit square which were obtained by using a concept of good integrity basis to some constructions of invariant cubature formulas over the unit cube, a Reynold operator will be used to obtain new invariant cubature formulas over the unit cube. In order to practically find integration nodes and weights for the cubature formulas, it is required to solve a system of nonlinear equations. With an IMSL subroutine DUNLSF which is used for solutions of the system of nonlinear equations, we shall give integration nodes for the new invariant cubature formulas over the unit cube depending on each degree of polynomial precision.

• Journal of Korean Neurosurgical Society
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• v.30 no.5
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• pp.657-661
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• 2001

Intracranial giant aneurysms have been known to cause clinical signs and symptoms, either by rupture, compression of surrounding structures, repeated minor leakage, or cerebral ischemia due to thromboembolism. A giant aneurysm which manifests only a seizure disorder comprises relatively few contributions. The authors present a case of a giant, unruptured aneurysm solely presenting with generalized tonic-clonic type seizure in a 43-year-old man. Brain computed tomogram(CT) and 3-D CT angiogram demonstrated a huge calcified aneurysm at the bifurcation of right middle cerebral artery. Complete neck clipping and aneurysmectomy followed by uneventful neurologic recovery.

• Bulletin of the Korean Chemical Society
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• v.28 no.3
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• pp.391-396
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• 2007

The three-dimensional structure of an inorganic crystal, CaMoO4 (space group I 41/a, a = 5.198(69) A and c = 11.458(41) A), was determined by electron crystallography utilizing a high voltage electron microscope. An initial structure of CaMoO4 was determined with 3-D electron diffraction patterns. This structure was refined by crystallographic image processing of high resolution TEM images. X-ray crystallography of the same material was performed to evaluate the accuracy of the TEM structure determination. The cell parameters of CaMoO4 determined by electron crystallography coincide with the X-ray crystallography result to within 0.033-0.040 A, while the atomic coordinates were determined to within 0.072 A.

• Journal of Korean Society for Quality Management
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• v.43 no.4
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• pp.573-588
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• 2015

Purpose: For improving result of estimated remaining useful life in Prognostics and Health Management (PHM), a system which is able to consider a lot of environment and load data is required. Method: A load profile monitoring system was presented based on cloud computing for gathering and processing raw data which is included environment and load data. Result: Users can access results of load profile information on the Internet. The developed system provides information which consists of distribution of load data, basic statistics, etc. Conclusion: We developed the load profile monitoring system for considering much environment and load data. This system has advantages such as improving accessibility through smart device, reducing cost, and covering various conditions.

• Journal of Mushroom
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• v.8 no.3
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• pp.102-108
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• 2010

In this study, growth rates and enzyme activities of mushroom mycelium were investigated in each cereals. Cultivation on hulled barley resulted in slightly faster mycelial growth as compared to other substrates. Enzyme activities were measured in different periods. In result, ${\alpha}$-amylase activity was higher in Pleurotus ostreatus and Phellinus linteus cultured cereals, whereas ${\beta}$-amylase activity was higher in Pleurotus ostreatus and Fomitella fraxinea cultured. Protease level did not affect kinds of cereal except Phellinus linteus. The color values lightness decrease by Basidiomycetes cultivation and redness and yellowness increased.

• Annals of Clinical Neurophysiology
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• v.10 no.1
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• pp.52-57
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• 2008

Even though the origin and nature of nocturnal paroxysmal dystonia (NPD) remains unclear, it has been considered as a manifestation of the nocturnal frontal lobe epilepsy. We report a 17-year-old man with abnormal stereotyped movement during sleep. Video-EEG monitoring, ictal SPECT and night polysomnography did not show any evidence of epilepsy. However, the partial response to large dose of carbamazepine and the scoring according to the frontal lobe epilepsy and parasomnias (FLEP) scale suggest his events could be classified as epilepsy. Therefore we think the FLEP scale might be a useful tool for differential diagnosis in a patient presenting NPD.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.56-60
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• 1996

In most dynamic manufacturing environments today, systems and processes are constantly changing. Simulation tools are required that can accurately model the system in detail, but still be easy to use, and allow rapid model redevelopment to react quickly for system changes. An object-oriented simulation modeling environment is presented to provide flexible modeling capabilities for simulation. Also, when simulating an assembly system, a large number of factors must be considered. Because of such complexities, simulation has been used as the primary method in designing, planning and analyzing. In this paper, the dynamic manufacturing environment is discussed for the assembly system. Also, an application method of simulation tools is presented with the experimental data from the automobile manufacturing shop to improve the productivity effectively.

• Journal of Applied Reliability
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• v.10 no.3
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• pp.171-182
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• 2010

The reliability prediction analysis is a feedback tool that designer uses to provide insight into the component designs. This insight may indicate sensitive components within the design. This paper examines predicted failure rates for hybrid dc-dc converter for spacecraft using MIL-HDBK-217F prediction methodology. The results from part count/stress analysis represent priority components that affect the converter failures. The high priority components are analyzed to find out stress factor based on MIL-HDBK-217F. This information provides an opportunity for designer to improve the reliability of the product in development process.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.788-792
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• 2013

A shortcoming of using transmission electron microscopy (TEM) for structural analysis via electron diffraction is the relatively large error of the measurements as compared to X-ray diffraction. To reduce these errors, various internal standard methods from earlier studies have been widely used. We developed a new device to facilitate the application of internal standard methods in preparation of TEM grids used for nanopowder analysis. Through the application of a partial mask on the TEM grid, both the internal standards and the research materials can be loaded on the same grid. Through this process, we conducted a TEM analysis that compared synthetic hydroxyapatite (HAp) nanopowder to bone apatite from a bovine femur. We determined that the accuracy of the d-spacing measurements of the HAp and bone powders could be improved to better than 1% after statistical treatments of the experimental data. By applying a quarter mask, we loaded four different nanoparticles on a single TEM grid, with one section designated for the internal standard.