• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.307-312
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• 2005

As the various manufacturing technology of optical glass is developed, the aspherical lenses are applied to many fields. However, It is still very difficult to manufacture glass lens because of the high cost and the short life of core. In recent years, the demands of the aspherical glass lenses increase since it is difficult to obtain the desirable performance in the plastic lens. In the glass mold lens, it has merits of high productivity and reproductivity since lens is manufactured by the only forming with high precision mold. The fabricating conditions for glass mold lens are glass surface that does not cause fusion, viscosity of 108-1013 poise for the $0.2{\mu}m$ accuracy, and viscoelasticity for the roughness less than 100 angstrom. In this thesis, ultra-precision grinding characteristics of tungsten carbide for forming the aspherical glass lens core were studied and the result of it is applied to manufacture the tungsten carbide-base core of the glass lens used to the laser scanning unit and the camera phone.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.203-208
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• 2005

In recent years, as the demands of VBNS and VDSL increase, the development of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, and WDM elements increases. The alignment and the attachment technology are very important in the fabrication of optical elements. In this paper, the optical alignment characteristics of multi-axis ultra precision stage were studied. The alignment algorithms were studied for applying to the ultra precision multi-axis stage. The alignment algorithm is comprised of field search and peak search algorithms. The contour of optical power signals can be obtained by field search and the precise coordinate can be found out by peak search. Two kinds of alignments, such as 1 ch. input vs. 1 ch. output optical stack, and 1 ch. input vs. 8 ch. output PLC stacks were performed for investigating the alignment characteristics.

• Journal of Species Research
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• v.7 no.3
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• pp.187-192
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• 2018

During a comprehensive study of indigenous prokaryotic species in South Korea, nine bacterial species in the phylum Bacteroidetes were isolated from freshwater environmental samples that were collected from three major rivers in the Republic of Korea. High 16S rRNA gene sequence similarity (${\geq}98.7%$) and robust phylogenetic clades with the closely related species suggest that each strain was correctly assigned to an independent and predefined bacterial species. There were no previous reports of these nine species in Korea. Within the phylum Bacteroidetes, four species were assigned to the genus Flavobacterium, order Flavobacteriales, and five species to three genera of two families in the order Cytophagales. Gram reaction, colony and cell morphology, basic biochemical characteristics, isolation source, and strain IDs are described in the species description section.

• Molecules and Cells
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• v.21 no.1
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• pp.161-165
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• 2006

Dichlorodihydrofluorescein ($DCFH_2$) is a widely used probe for intracellular $H_2O_2$. However, $H_2O_2$ can oxidize $DCFH_2$ only in the presence of a catalyst, whose identity in cells has not been clearly defined. We compared the peroxidase activity of Cu,Zn-superoxide dismutase (CuZnSOD), cytochrome c, horseradish peroxidase (HRP), $Cu^{2+}$, and $Fe^{3+}$ under various conditions to identify an intracellular catalyst. Enormous increase by bicarbonate in the rate of $DCFH_2$ oxidation distinguished CuZnSOD from cytochrome c and HRP. Cyanide inhibited the reaction catalyzed by CuZnSOD but accelerated that by $Cu^{2+}$ and $Fe^{3+}$. Oxidation of $DCFH_2$ by $H_2O_2$ in the presence of a cell lysate was also enhanced by bicarbonate and inhibited by cyanide. Confocal microscopy of $H_2O_2$-treated cells showed enhanced DCF fluorescence in the presence of bicarbonate and attenuated fluorescence for the cells pre-incubated with KCN. Moreover, DCF fluorescence was intensified in CuZnSOD-transfected HaCaT and RAW 264.7 cells. We propose that CuZnSOD is a potential intracellular catalyst for the $H_2O_2$-dependent oxidation of $DCFH_2$.

• Korean Journal of Clinical Oncology
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• v.14 no.2
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• pp.116-119
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• 2018

Purpose: This study assessed the effect of chemotherapy over stage II colon cancer in terms of presence of high-risk factors. Methods: Data were retrospectively reviewed for 364 patients with stage II colon cancer who underwent curative surgery between January 2007 and December 2012. High-risk factors of stage II colon cancer were examined, and the overall survival (OS) rates were analyzed. Survival benefit of adjuvant chemotherapy was also analyzed. Results: One hundred and fifteen cases had exclusively single high-risk factor and 194 cases were negative for high-risk factors. Postoperative chemotherapy was performed in 262 of 364 patients (72.0%). The 5-year OS was 79.4% and 86.6% for patients without adjuvant chemotherapy and those with chemotherapy, respectively. The 5-year OS was 88.2% and 83.3% for patients having exclusively single high-risk factor with adjuvant chemotherapy and those without chemotherapy, respectively. Conclusion: Adjuvant chemotherapy for patients with stage II colon cancer having exclusively single high-risk factor could be omitted, weighing up the survival benefit and side effect of chemotherapy.

• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.103-109
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• 2018

This paper presents an idea and framework to automate a full cycle business process management and re-engineering by integrating traditional business process management systems, process mining, data mining, machine learning, and simulation. We build our framework on the cloud-based platform such that various data sources can be incorporated. We design our systems to be extensible so that not only beneficial for practitioners of BPM, but also for researchers. Our framework can be used as a test bed for researchers without the complication of system integration. The automation of redesigning phase and selecting a baseline process model for deployment are the two main contributions of this study. In the redesigning phase, we deal with both the analysis of the existing process model and what-if analysis on how to improve the process at the same time, Additionally, improving a business process can be applied in a case by case basis that needs a lot of trial and error and huge data. In selecting the baseline process model, we need to compare many probable routes of business execution and calculate the most efficient one in respect to production cost and execution time. We also discuss the challenges and limitation of the framework, including the systems adoptability, technical difficulties and human factors.

• Journal of the Korean institute of surface engineering
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• v.54 no.4
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• pp.209-214
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• 2021

As coffee consumption per person increases annually to 323 cups in 2018, treating the spent coffee ground has arisen because spent coffee ground results in soil and air pollution. The demands of air purification filters are increasing more and more because the air pollution due to the fine dust has become worse. The spent coffee grounds had a porous structure, however, the pore was blocked by organic oil compounds. Electrocoagulation, which is one of the electrochemical methods, has the potential to remove the organic compounds. The surface area of spent coffee grounds increased effectively after the electrocoagulation treatment, and surface morphology and surface area were confirmed using SEM and BET, respectively. Using the FT-IR, both the spent coffee grounds and the electrocoagulated spent coffee grounds were characterized. The filter characteristics were examined by the adsorption test using formaldehyde, one of the air pollutants.

• Journal of the Korean institute of surface engineering
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• v.54 no.4
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• pp.194-199
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• 2021

In this study, rebar corrosion detection sensor was fabricated using multi-walled carbon nanotubes (MWCNTs). MWCNTs were pre-treated in the acid electrolytes to attach the carboxylic acid to the surface of MWCNTs. The fabricated sensor was attached on the surface of rebar and it detected the corrosion of steel using LCR meter with variation of capacitance. The surface morphology and electrical properties were characterized using scanning electron microscope (SEM) and electrical test equipment, respectively. To verify the corrosion detection characteristics, comparison experiment using plastic bar was performed. Moreover, mechanism of corrosion detection sensor was discussed.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.4
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• pp.541-550
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• 2022

When decommissioning nuclear power plant (NPP), the first task performed is cost estimation. This is an important task in terms of securing adequate decommissioning funds and managing the schedule. Therefore, many countries and institutions are conducting continuous research and also developing and using many programs for cost estimation. However, the cost estimated for decommissioning an NPP typically differs from the actual cost incurred in its decommissioning. This is caused by insufficient experience in decommissioning NPPs or lack of decommissioning cost data. This uncertainty in cost estimation can be in general compensated for by applying a contingency. However, reflecting an appropriate standard for the contingency is also difficult. Therefore, in this study, data analysis was conducted based on the contingency guideline suggested by each institution and the actual cost of decommissioning the NPP. Subsequently, TLG Service, Inc.'s process, which recently suggested specific decommissioning costs, was matched with ISDC (International Structure for Decommissioning Costing)'s work breakdown structure (WBS). Based on the matching result, the guideline for applying the contingency for ISDC's WBS Level 1 were presented. This study will be helpful in cost estimation by applying appropriate contingency guidelines in countries or institutions that have no experience in decommissioning NPPs.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.442-454
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• 2022

A total of 31 bacterial strains were isolated from the Geum River basin in the Republic of Korea during our investigation of indigenous prokaryotic species. The isolated bacterial strains had high 16S rRNA gene sequence similarity (>98.7%) with those of validly published bacterial species, which have not been reported in Republic of Korea. The 31 bacterial strains were phylogenetically diverse and assigned to 4 phyla, 8 classes, 18 orders, 21 families, and 27 genera. At the genus level, the unreported species were affiliated with Kineococcus, Pedococcus, Rhodoluna, Salinibacterium, Rhodoluna, Arthrobacter, Williamsia, Nakamurella, Nocardioides of the class Actinobacteria, Patulibacter of the class Thermoleophilia, Pontibacter, Hymenobacter of the class Cytophagia, Flavobacterium of the class Flavobacteriia, Geomicrobium of the class Bacilli, Brevundimonas, Gellertiella, Rhizobium, Paracoccus, Taonella, Sphingomonas of the class Alphaproteobacteria, Burkholderia, Polaromonas, Hydrogenophaga, Chitinilyticum, Azospira, Zoogloea of the class Betaproteobacteria, and Pseudomonas of the class Gammaproteobacteria. The unreported bacterial species were further characterized by examining their morphological, cultural, physiological, and biochemical properties. The detailed descriptions of the 31 bacterial strains were provided.