• 천문학회보
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• 제42권2호
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• pp.56.3-56.3
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• 2017

The Breakthrough Starshot initiative aims to launch gram-scale spacecraft to a speed of v~0.2c, capable of reaching Alpha Centauri and seeing the Earth-like exoplanet, Proxima b, from close distance, in about 20 years. However, a critical challenge for the initiative is the effects of interstellar matter and magnetic field to the relativistic spacecraft during the journey. In this talk, I will first present our evaluation for the damage to the spacecraft by interstellar gas and dust based on a detailed analysis of the interaction of a relativistic spacecraft with the ISM. Second, I will discuss the deflection and oscillation of spacecraft by interstellar magnetic fields. Third, I will discuss the gas drag fore at high energy regime and quantify its effect on the slowing down of the relativistic lightsails. Finally, we will discuss practical strategies to mitigate the damage by interstellar dust and to maintain the spacecraft aiming at the intended target.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.261-264
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• 2014

• Journal of Electrical Engineering and information Science
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• 제2권5호
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• pp.79-88
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• 1997

This paper introduces a new energy function, as maximum a posteriori(MAP) estimate of binocular disparity, that can deal with both random dot stereo-gram(RDS) and natural scenes. The energy function uses phase-magnitude as features to detect only the shift for a pair of corrupted conjugate images. Also we adopted Fleet singularity that effectively detects unstable areas of image plant and thus eliminates in advance error-prone stereo mathcing. The multi-scale concept is applied to the multi laser architecture that can search the solutions systematically from coarse to fine details and thereby avoids drastically the local minima. Using mean field approximation, we obtained a compact representation that is suitable for fast computation. In this manner, the energy function satisfies major natural constraints and requirements for implementing parallel relaxation. As an experiment, the proposed algorithm is applied to RDS and natural stereo images. As a result we will see that it reveals good performance in terms of recognition errors, parallel implementation, and noise characteristics.

• Journal of information and communication convergence engineering
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• 제21권3호
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• pp.244-251
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• 2023

Engineering or humanities data are stored in databases and are often used for search services. While the latest deep-learning technologies, such like BART and BERT, are utilized for data analysis, humanities data still rely on traditional databases. Representative analysis methods include n-gram and lexical statistical extraction. However, when using a database, performance limitation is often imposed on the result calculations. This study presents an experimental process using MariaDB on a PC, which is easily accessible in a laboratory, to analyze the impact of the database on data analysis performance. The findings highlight the fact that the database becomes a bottleneck when analyzing large-scale text data, particularly over hundreds of thousands of records. To address this issue, a method was proposed to provide real-time humanities data analysis web services by leveraging the open source database, with a focus on the Seungjeongwon-Ilgy, one of the largest datasets in the humanities fields.

• Journal of Biosystems Engineering
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• 제37권4호
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• pp.233-244
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• 2012

Purpose: The kinetic evaluation was performed for swine manure (SM) degradation and biogas generation. Methods: The SM was anaerobically digested using batch digesters at feed to inoculum ratio (F/I) of 1.0 under mesophilic conditions ($36.5^{\circ}C$). The specific gas yield was expressed in terms of gram total chemical oxygen demand (mL/g TCOD added) and gram volatile solids added (mL/g VS added) and their effectiveness was discussed. The biogas and methane production were predicted using first order kinetic model and the modified Gompertz model. The critical hydraulic retention time for biomass washout was determined using Chen and Hashimoto model. Results: The biogas and methane yield from SM was 346 and 274 mL/ TCOD added, respectively after 100 days of digestion. The average methane content in the biogas produced from SM was 79% and $H_2S$ concentration was in the range of 3000-4108 ppm. It took around 32-47 days for 80-90% of biogas recovery and the TCOD removal from SM was calculated to be 85%. When the specific biogas and methane yield from SM (with very high TVFA concentration) was expressed in terms of oven dried volatile solids (VS) basis, the gas yield was found to be over estimated. The difference in the measured and predicted gas yield was in the range of 1.2-1.5% when using first order kinetic model and 0.1% when using modified Gompertz model. The effective time for biogas production ($T_{Ef}$) from SM was calculated to be in the range of 30-45 days and the critical hydraulic retention time ($HRT_{Critical}$) for biomass wash out was found to be 9.5 days. Conclusions: The modified Gompertz model could be better in predicting biogas and methane production from SM. The HRT greater than 10 days is recommended for continuous digesters using SM as feedstock.

• 사상체질의학회지
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• 제22권3호
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• pp.51-58
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• 2010

1. Objectives: After arranging the contents of the usages of Aconite mentioned in the literature - "Dongmu", a power trend me to further study the details of the usages of Aconite. 2 Methods: This study mainly refers to; "Dongmu-YuGo(東武遺稿)"(DYG), "Donguisusebowon-SaSangchobongyun(東醫壽世保元四象草本卷)"(DSS), "Donguisusebowon-GabObon(東醫壽世保元甲午本)"(DGO), "Donguisusebowon-ShinChukbon(東醫壽世保元辛丑本)"(DSC), and the research was written in order to find out the physiology and pathology of Soeumin in SCM. 3 Results and Conclusions 1) Taking aconite in a scale of 3 to 15 gram as common dosage, especially, when a person was critically ill, the dosage of 45 gram was used. Different dosages of aconite were chosen in accordance with some other different conditions, such as the purpose of reducing fever or mid-energizer warming, urinary volume, presence or absence of edema, stages of growth of diseases. In addition, we found a remedy using Remedy Single head garlic(獨頭蒜) instead of aconite. 2) Adverse toxic effects of aconite can be serious, it is dangerous to patients who are administered with aconite in massive amounts or take it in different concocting methods, therefore, further evidence about the laboratory experiments studied in animals and clinical dataare needed to confirm the scope for more widespread and accurate usages of Aconite.

• 한국환경보건학회지
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• 제30권5호
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• pp.440-448
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• 2004

Airborne bacteria, gram negative bacteria (GNB) and fungi were measured in 70 class of 17 kindergartens. The objective of this study is to identify the factors influencing airborne concentrations of bacteria, GNB and fungi using multiple regression analysis. The average concentrations of bacteria and fungi exceeded $1,000\;CFU/m^3$. The average of GNB was $3.7{\times}10^2\;CFU/m^3$. This results indicated that air of kindergartens was contaminated with microbes such as bacteria and fungi. ANOVA test found that the concentrations of bacteria, GNB and fungi were significantly different by the characteristics of weather (rain, after rain, sunny) sampling date (July, August, September and October), the location of sampling site (ground level and basement) and the location of toilet (inside class, nearby class and away class). Multiple regression tests concluded that sampling date, the scale of city where kindergartens are located, the location of sampling site and ventilation efficiency can significantly affect the airborne concentration of bacteria, GNB and fungi. Most of these factors could be related moisture. Environmental factors that can cause the increment of moisture should be controlled in order to reduce airborne concentration of bacteria, GNB and fungi. Legal actions concerning prohibition on the presence of toilet inside class and ventilation criteria should be taken.

• Journal of Microbiology and Biotechnology
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• 제24권4호
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• pp.522-533
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• 2014

Bionanotechnology has revolutionized nanomaterial synthesis by providing a green synthetic platform using biological systems. Among such biological systems, microalgae have tremendous potential to take up metal ions and produce nanoparticles by a detoxification process. The present study explores the intracellular and extracellular biogenic syntheses of silver nanoparticles (SNPs) using the unicellular green microalga Scenedesmus sp. Biosynthesized SNPs were characterized by AAS, UV-Vis spectroscopy, TEM, XRD, FTIR, DLS, and TGA studies and finally checked for antibacterial activity. Intracellular nanoparticle biosynthesis was initiated by a high rate of $Ag^+$ ion accumulation in the microalgal biomass and subsequent formation of spherical crystalline SNPs (average size, 15-20 nm) due to the biochemical reduction of $Ag^+$ ions. The synthesized nanoparticles were intracellular, as confirmed by the UV-Vis spectra of the outside medium. Furthermore, extracellular synthesis using boiled extract showed the formation of well scattered, highly stable, spherical SNPs with an average size of 5-10 nm. The size and morphology of the nanoparticles were confirmed by TEM. The crystalline nature of the SNPs was evident from the diffraction peaks of XRD and bright circular ring pattern of SAED. FTIR and UV-Vis spectra showed that biomolecules, proteins and peptides, are mainly responsible for the formation and stabilization of SNPs. Furthermore, the synthesized nanoparticles exhibited high antimicrobial activity against pathogenic gram-negative and gram-positive bacteria. Use of such a microalgal system provides a simple, cost-effective alternative template for the biosynthesis of nanomaterials in a large-scale system that could be of great use in biomedical applications.

• 한국미생물·생명공학회지
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• 제16권6호
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• pp.522-525
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• 1988

무혈청 배지에 생산촉진제로 30$\mu$g/m$\ell$의 Heparin 을 첨가해 정상인의 섬유 세포로부터 상업적으로 tPA를 생산할 수 있는 방법의 개발과, 효과적인 tPA 생산을 위해 대량 배양에 적합한 무혈청 배지의 조성을 확립했다. 이 방법으로 연속배양 공법하에서 매일 1.1gram의 tPA가 생산될 수 있으며, 이 생산성은 tPA 생산 단가를 크게 낮출 분만 아니라 무혈청 배지의 사용으로 tPA의 순수 정제 과정을 크게 단축시킬 수 있다. 또한 이 세포에서 생산되는 tPA 는 fibrin lysis 시험결과 섬유질 분해능력이 높음이 입증되었으며, ELISA결과와도 상충했다.

• Journal of Microbiology and Biotechnology
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• 제31권5호
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• pp.756-763
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• 2021

Agarose is a linear polysaccharide composed of ᴅ-galactose and 3,6-anhydro-ʟ-galactose (AHG). It is a major component of the red algal cell wall and is gaining attention as an abundant marine biomass. However, the inability to ferment AHG is considered an obstacle in the large-scale use of agarose and could be addressed by understanding AHG catabolism in agarolytic microorganisms. Since AHG catabolism was uniquely confirmed in Vibrio sp. EJY3, a gram-negative marine bacterial species, we investigated AHG metabolism in Streptomyces coelicolor A3(2), an agarolytic gram-positive soil bacterium. Based on genomic data, the SCO3486 protein (492 amino acids) and the SCO3480 protein (361 amino acids) of S. coelicolor A3(2) showed identity with H2IFE7.1 (40% identity) encoding AHG dehydrogenase and H2IFX0.1 (42% identity) encoding 3,6-anhydro-ʟ-galactonate cycloisomerase, respectively, which are involved in the initial catabolism of AHG in Vibrio sp. EJY3. Thin layer chromatography and mass spectrometry of the bioconversion products catalyzed by recombinant SCO3486 and SCO3480 proteins, revealed that SCO3486 is an AHG dehydrogenase that oxidizes AHG to 3,6-anhydro-ʟ-galactonate, and SCO3480 is a 3,6-anhydro-ʟ-galactonate cycloisomerase that converts 3,6-anhydro-ʟ-galactonate to 2-keto-3-deoxygalactonate. SCO3486 showed maximum activity at pH 6.0 at 50℃, increased activity in the presence of iron ions, and activity against various aldehyde substrates, which is quite distinct from AHG-specific H2IFE7.1 in Vibrio sp. EJY3. Therefore, the catabolic pathway of AHG seems to be similar in most agar-degrading microorganisms, but the enzymes involved appear to be very diverse.