• Journal of Intelligence and Information Systems
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• v.10 no.1
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• pp.13-25
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• 2004

In the online shopping environment, consumers suffer from the process of selecting an optimal supplier. Although comparison shopping agent-based web sites and consumers' online community sites support the selection process, they have limitations when considering diverse and dynamic purchase conditions as a whole, which is the cause of additional consumer effort for optimal supplier selection. This study provides a decision support model with a sensitivity analysis for selecting an optimal supplier considering purchase conditions as a whole. It screens suppliers with filtering factors and provides optimal suppliers through a sensitivity analysis from a Quadratic Programming model. We implemented a prototype system and showed that it could be an effective decision support system for selecting the optimal supplier in the online shopping environment.

• Resources Recycling
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• v.18 no.5
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• pp.72-81
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• 2009

The demand for platinum group metals for various advanced industries has been growing due to their excellent physical and chemical properties. Since the deposit of platinum minerals are restricted to few countries, their recovery from various secondary resources has becomes an important issue to related industries for keeping the supply reliably. In this paper, patents on the metallurgical technologies for the platinum group metals were analyzed. The search of patent was limited to the open patents of USA (US), European Union (EP), Japan (IP), and Korea (KR) from 1986 to 2006. Patents were surveyed using key-words searching and selected by filtering criteria. The trend of patents was analyzed by the years, countries, companies, and technologies.

• Journal of the Korean Ceramic Society
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• v.40 no.6
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• pp.560-565
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• 2003

M-doped (M=Al, Ni) ZnO thermoelectric materials were fully densified at low temperatures of 800∼1,000$^{\circ}C$ and their sintering characteristics and microstructural features were investigated. Electron microscopic analysis showed that the addition of NiO promoted tile formation of solid solution and caused actively grain growth. The addition of A1$_2$O$_3$ prevented the evaporation of pure ZnO at grain boundaries and suppressed the grain growth by the formation of secondary phase. In case of the addition of A1$_2$O$_3$ together with NiO, the specimen showed an excellent microstructure and also the SEM-EBSP (Electron Back-scattered Diffraction Pattern) analysis confirmed that it shows a superior grain boundary distribution to the others specimens. These microstructural characteristics induced by the addition of A1$_2$O$_3$ together with NiO may increase the electrical conductivity by the increase in carrier concentration and decrease the thermal conductivity by the phonon scattering effect and, consequently, improve the thermoelectric property.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.1
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• pp.91-104
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• 2008

In tunnels, safety factor concept has been suggested to estimate their stability quantitatively. It is merely limited in the framework of mechanical analysis. However safety factor concept has not been applied in hydro-mechanical coupled analyses due to their modelling complexity. Recently studies on this topic are being actively made. In this study, induced drainage modelling methods for hydro-mechanical coupled analyses are compared and analyzed to estimate safety factor of a subsea tunnel exactly. To this end, methods both controlling hydraulic characteristic of shotcrete and using a drainage well are considered. Sensitivity analysis were carried out on rock class, thickness of shotcrete, and hydraulic properties of rock mass. As the results of this study, it turned out that the induced drainage modelling using a drainage well would give more reliable results than that of controlling hydraulic characteristic of shotcrete in estimating tunnel stability in hydro-mechanical coupled analyses.

• Food Science and Preservation
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• v.13 no.2
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• pp.119-124
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• 2006

This study was conducted to optimize roasting process of Job's tears for utilization as food Optimal condition for masting was investigated with changes in temperature and time by response surface methodology. The qualities of water extract such as browning degree, polyphenol and DPPH radical scavenging ability were affected more by roasting temperature than time. The values increased with temperature and time proportionally. The response variables were more significant with temperature than time and the established polynomial model was suitable (P>0.05) model by Lack-of-Fit analysis. Optimal roasting conditions with the limit of $0.2{\sim}0.3$ browning degree, $2.0{\sim}2.5{\mu}g/mL$ polyphenol, $30{\sim}40%$ scavenging ability and $0{\sim}100$ hue angle were $215^{\circ}C$ and 32 min.

• KSBB Journal
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• v.19 no.1
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• pp.72-77
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• 2004

The aim of this study was to isolate and identify the spoilage bacteria in the low salt cucumber brine. The PCR amplicons comprising a portion of the 16S rRNA gene of the isolated colonies were directly sequenced and the untrimmed whole sequencing results of the unknown strains were aligned with the type strains using BLAST of NCBI. Then Sequence Aligner and Sequence Match of RDP confirmed the outcome. The identified isolates were eight species and belong to three genuses: Clostridium, Lactobacillus, and Bacillus. The RFLP pattern of the 16S rRNA gene of isolates verified the identified species. From now on the complex spoiling process of law salt fermented cucumber could be analyzed using the isolated species individually or with certain combinations.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.3
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• pp.310-319
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• 2012

In order to investigate the biological effects of conformational changes in the folding state of bovine ${\alpha}$-lactalbumin (${\alpha}$-La), the protein was prepared and classified as apo form, microbial transglutaminase (MTGase) added form, or bovine ${\alpha}$-La made lethal to tumor cell (BAMLET) form. Apo ${\alpha}$-La form showed weaker cancer cell inhibitory activity (apoptosis) than native ${\alpha}$-La, which suggests that the metal ion-like $Ca^{2+}$ had a positive effect, whereas BAMLET form showed strong cancer cell apoptotic activity. The BAMLET form seemed to be a molten globule structure that increased hydrophobicity. MTGase added to apo ${\alpha}$-La polymer showed similar anti-cancer activity as native ${\alpha}$-La, and it was well hydrolyzed by digestive enzymes. NMR results showed that BAMLET interacted with oleic acid and produced a complex.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.193-194
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• 2012

그래핀(graphene)은 탄소원자가 육각형 벌집 모양 배열의 격자구조를 가지는 원자 한층 두께의 이차원 물질이다. 그래핀은 전도띠(conduction band)와 가전자띠(valence band)가 한 점에서 만나고 에너지와 역격자의 k 벡터가 선형적으로 비례하는 에너지 구조를 가진다. 이로 인해 그래핀은 매우 빠른 전하 이동도를 가지며 원자 한 층의 두께임에도 불구하고 약 2.3%의 빛을 흡수할 수 있으며 자외선 영역부터 적외선 영역까지의 넓은 파장대의 빛을 흡수 할 수 있다. 이와 같은 그래핀의 우월한 성질을 이용하면 광 응답에 고속으로 반응하고 높은 주파수의 광통신에서도 작동 할 수 있는 그래핀 광소자를 제작할 수 있게 된다. 하지만 미래의 고속 그래핀 광소자를 실현하기에 앞서 그래핀의 광응답에 대한 정확한 이해가 필요하다. 그리하여 본 연구에서는 그래핀 광소자를 제작하고 광소자의 광응답 전기적 성질을 분석하여 그래핀의 광응답 특성을 얻어내고자 실험을 진행하였다. 그래핀을 채널 물질로 하고 소스, 드레인, 후면 게이트를 가지는 일반적인 그래핀 전계효과 트랜지스터(field-effect transistor)를 제작하고 채널에 빛을 비추고 비추지 않은 상태에서의 전기적 성질을 측정하고 그 때 얻어진 그래프의 광응답의 원인을 조사하였다. 이 때 얻어지는 $I_D-V_G$ 그래프가 광 조사 시 왼쪽으로 이동하게 되는데 이의 원인을 각 게이트 전압 구간별로 $I_D$-t 그래프를 획득하여 분석하였다. 또한 광원에 펄스를 인가하여 펄스 형태의 광원을 그래핀 전계효과 트랜지스터에 조사시키고 이에 따른 전기적 성질 변화를 관찰하였다 이 때 다양한 게이트 전압이 인가된 상태에서 레이저 펄스 광원에 의한 광전류를 검출하였으며 이를 분석하였다.

• Korean Journal of Materials Research
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• v.1 no.4
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• pp.214-220
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• 1991

The effects of $SiO_2$ reactive ion etching (RIE) in $CHF_{3/}C_2F_6$ on the surface properties of the underlying Si substrate were studied by X-ray photoelectron spectroscopy(XPS) and secondary ion mass spectrometry(SIMS) techniques. Angle-resolved XPS analysis was carried out as non-destructive depth profile one for investigating the chemical bonding states of silicion, carbon, oxygen and fluorine. The residue layer consists of C-F polymer. O-F bond was found on the top of the polymer layer and Si-O, Si-C and Si-F bonds were detected between Si substrate and polymer film. A 60nm thick damaged layer of silicon surface mainly contains carbon and fluorine.

• Journal of Educational Research in Mathematics
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• v.27 no.4
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• pp.765-789
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• 2017

Arithmetic is the basis of school mathematics and in fact, number and operation in elementary school curriculum is the most basic and essential domain. Even though there has been a consensus that arithmetic should be taught more meaningfully beyond the emphasis of calculation skills and teachers should emphasize the aspect of the arithmetical thinking, it is difficult to find studies which focus on the arithmetical thinking itself. So this research aims to explore the meaning of the arithmetical thinking and extract the arithmetical thinking factors. In order to solve the research problems, we reviewed and analyzed the literatures and then conducted Delphi survey to extract arithmetical thinking factors. From the results of this research, we found the meaning of arithmetical thinking and the arithmetical thinking factors. Especially, the arithmetical thinking consists of 18 factors. It is important to pay attention to students' arithmetical thinking because there are various factors of the arithmetical thinking. It is necessary to identify the aspects of arithmetical thinking reflected in school mathematics based on the meaning of arithmetical thinking and its factors. Based on this, it is possible to find effective teaching and learning methods of arithmetic focusing on the arithmetical thinking.