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Calculation on Electronic State and Chemical Bonding of $\beta$-$MnO_2$ by DV-X$\alpha$ Method (분자궤도계산법에 의한 $\beta$-$MnO_2$의 전자상태 및 화학결합 계산)

  • 이동윤;김봉서;송재성;김현식
    • Korean Journal of Crystallography
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    • v.14 no.1
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    • pp.16-23
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    • 2003
  • The electronic structure and chemical bonding of β-MnO₂ were theoretically investigated by DV-X/sub α/ (the discrete variation X/sub α/) method. which is a sort of the first principle molecular orbital method using Hatre-Fock-Slater approximation. The calculations on several cluster models having different sizes were carried out for the determination of a model suited for analyzing bulk state. The Mn/sub 15/O/sub 56/ model was selected as a sufficiently suitable model for the calculation of electronic state and chemical bonding by the comparison of the calculated XPS (X-ray photo-electron spectrum) and experimentally measured XPS. By using this model, the electron energy level, the density of state, the bond overlap population, the charge density distribution, and the net ionic transfer between cations and anions were calculated and discussed.

Characterization of Cordierite by XPS (Ⅰ) (XPS에 의한 코디에리트의 특성 연구 (연구Ⅰ))

  • Han, Byoung-Sung
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.3
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    • pp.124-129
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    • 1989
  • The cordierite is of great interest for microelectronic packaging. Its main advantages are low dielectric constant and low thermal expansion. The cordierite precursor obtained by sol-gel synthesis whose sintering temperature is about $900^{circ}C$ is an amorphous and cristal white powder. Green and fired cordierite samples were studied by XPS for microscopic properties. At the surface the results of XPS show forte diminution of Mg in comparison with its value at volume and the deficit of Mg compensates by augmentation of Al and Si. $pi$-cordierite phase is present near the surface $<100{\AA}$ and small quantities of magnesium aluminate ($MgAl_2O_4) is present in the bulk. Sintering of the green cordierite introduces no chemical modification at the surface.

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Importance of Accurate Charges in Binding Affinity Calculations: A Case of Neuraminidase Series

  • Park, Kichul;Sung, Nack Kyun;Cho, Art E.
    • Bulletin of the Korean Chemical Society
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    • v.34 no.2
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    • pp.545-548
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    • 2013
  • It has been shown that calculating atomic charges using quantum mechanical level theory greatly improves the accuracy of docking. A protocol was developed and shown to be effective. That this protocol works is just a manifestation of the fact that electrostatic interactions are important in protein-ligand binding. In order to investigate how the same protocol helps in prediction of binding affinities, we took a series of known cocrystal structures of influenza neuraminidase inhibitors with the receptor and performed docking with Glide SP, Glide XP, and QPLD, the last being a workflow that incorporates QM/MM calculations to replace the fixed atomic charges of force fields with quantum mechanically recalculated ones at a given docking pose, and predicted the binding affinities of each cocrystal. The correlation with experimental binding affinities considerably improved with QPLD compared to Glide SP/XP yielding $r^2$ = 0.83. The results suggest that for binding sites, such as that of neuraminidase, which are laden with hydrophilic residues, protocols such as QPLD which utilizes QM-based atomic charges can better predict the binding affinities.

A Study on the Urban Flood Damage Reduction Using the LID Under Climate Change : Case Study on Gulpo Stream Basin (기후변화에 따른 도시홍수 저감방안으로서의 LID 기법 적용성 평가 - 굴포천 유역을 대상으로 -)

  • Song, Chang-Joon;Kim, Soo-Jun;Kim, Hung-Soo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2010.05a
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    • pp.1169-1173
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    • 2010
  • 기후변화의 영향은 전세계적으로 재해를 가중시키는 역할을 하고 있다. 특히 인구밀도와 자산가치가 높은 도시지역의 홍수피해가 급증함에 따라 이를 방지하기 위한 대책마련이 시급히 요구되고 있다. 본 연구에서는 미래의 기후변화에 대응하기 위한 방안으로 도심지역에 LID(Low Impact Development)기법을 적용하여 도시 홍수의 저감방안으로서 그 적용성을 평가하고자 하였다. 이를 위해, 굴포천 유역을 대상으로 XP-SWMM을 이용하여 관망을 구축하고 현재 강우자료(1961~2000년)와 미래의 강우자료(KMA-A2 기후변화 시나리오, 2001~2090년)를 적용하여 현재와 미래의 강우조건에 따른 도심지역의 홍수범람 및 유출량을 산정하였다. 이 결과를 바탕으로 모델링된 지역 중, 기후변화 전후의 상습 홍수범람지역을 우선적으로 선정하여 LID기법을 적용하였다. 효율적인 LID기법의 적용을 위해 토지이용 변화에 따른 시나리오를 작성하고, 이에 따른 유출곡선지수(Curve Number, CN)값을 산정하여 도시홍수 범람지역 및 유출량의 변화를 검토하는데 이용하였다. 분석 결과, LID기법을 적용하였을 경우 기후변화에 따른 도심지역의 홍수 및 유출량을 현재 수준으로 낮출 수 있다는 결과를 얻을 수 있었다. 본 연구를 통하여 개발이 완료된 도시지역에도 효율적인 LID기법의 적용에 따라 도시홍수 및 유출량을 효과적으로 저감할 수 있을 뿐만 아니라, 기후변화에 대응하기 위한 하나의 대응책으로써 충분한 역할을 할 수 있을 것이라고 판단된다.

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A Survey-based Analysis of Agile Adoption on Performances of IT Organizations

  • Ghani, Imran;Bello, Mannir;Bagiwa, Idris Lawal
    • Journal of Internet Computing and Services
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    • v.16 no.5
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    • pp.87-92
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    • 2015
  • Numerous IT organizations and companies around the world aspire to improve the efficiency and general standard of their software development. The IT organizations want to seize the opportunities and take advantages of new development processes and methodologies. These advantages include higher customers' satisfaction and better software quality among many. In order to achieve them, different agile software methodologies such as scrum, Feature driven development, eXtremeProgramming (XP), Dynamic system development method, Kanban and others have been frequently adopted by IT organizations across the world. Several studies have shown that agile software development methods are effective in a lot of settings. This study, in which 40 agile practitioners from Malaysia participated, additionally confirms the effectiveness of agile development methods. Furthermore, this paper presents some of the critical barriers not well-known by IT-organizations. The results of this analysis can be used to guide IT organization from the obstacles they may face while adopting agile in their environments.

Monitoring System of File Outflow through Storage Devices and Printers (저장매체와 프린터를 통한 파일유출 모니터링시스템)

  • Choi Joo-ho;Rhew Sung-yul
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.15 no.4
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    • pp.51-60
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    • 2005
  • The riles or intellectual property on computer systems have increasingly been exposed to such threats that they can be flowed out by internal users or outer attacks through the network. The File Outflow Monitoring System monitors file outflows at server by making the toe when users copy files on client computers into storage devices or print them, The monitoring system filters I/O Request packet by I/O Manager in kernel level if files are flowed out by copying, while it uses Win32 API hooking if printed. As a result, it has exactly made the log and monitored file outflows, which is proved through testing in Windows 2000 and XP.

An Empirical Study of Security for API in Windows Systems (윈도우즈에서 제공되는 기본 API에 대한 안전성 고찰)

  • Choi, Young-Han;Kim, Hyoung-Chun;Oh, Hyung-Geun;Lee, Do-Hoon
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.19 no.2
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    • pp.75-82
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    • 2009
  • In this paper, we test for security targeting on APIs of Windows as that is used by many people worldwide. In order to test APIs in DLL fils of Windows OS, we propose Automated Windows API Fuzz Testing(AWAFT) that can execute fuzz testing automatically and implemented the practical tool for AWAFT. AWAFT focuses on buffer overflows and parsing errors of function parameters. Using the tool, we found 177 errors in the system folder of Windows XP SP2. Therefore, AWAFT is useful for security testing of Windows APIs. AWAFT can be applied to libraries of third party software in Windows OS for the security.

A Study on the Analysis of Flood inundations in Urban Areas according to Topographic Conditions (지형조건에 따른 도심지 내수침수 분석에 관한 연구)

  • Yeong Hun Son;Kye Won Jun;Min Ho Kim;Chang Deok Jang
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.330-330
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    • 2023
  • 이상기후로 인해 전국적으로 국지성 집중호우의 발생빈도와 규모가 증가하고 있다. 건물 및 도로의 증가와 토지이용변화와 같이 도시화가 이루어진 지역에 배수체계의 용량을 초과하는 강우의 발생으로 도심지 내수침수의 피해가 늘어나고 있다. 본 연구에서는 건물과 도로가 많은 도심지에서의 내수침수 분석을 위하여 2017년 7월과 2020년 8월에 침수 피해가 발생한 봉명지구를 연구대상 지역으로 선정하였으며, 건물과 도로의 영향을 고려하기 위해 이를 반영한 지형자료를 구축하였다. 내수침수를 분석하기 위해 XP-SWMM 모형을 이용하였으며, 피해 발생 당시의 침수심과 침수범위가 나타난 침수범람도를 바탕으로 각 지형조건에 따른 내수침수 분석 결과를 비교·검토하였다. 분석 결과 각 지형조건 중 건물과 도로를 반영한 지형에서의 침수심과 침수범위가 실제 피해와 가장 유사하게 나타났으며 특히 건물이 밀집되어 있는 좁은 골목에서의 수위와 흐름속도는 다른 지형조건에서 보다 높고 빠르게 나타난 것을 확인하였다. 월류수는 도로를 따라 하류로 이동하여 하류부 침수심이 가중되는 것으로 확인되었다.

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Development of optimal operating standards for deep stormwater storage-drain facilities for urban flood defense. (도시유역 홍수방어를 위한 대심도 빗물저류배수시설 최적운영기준 산정기법 개발)

  • Yoon, Jun-Seo;Moon, Hyeon-Tae;Moon, Young-Il
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.284-284
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    • 2022
  • 최근 세계적으로 급변하는 기후는 연 강수량이 여름에 집중되는 한국 강우 특성에 큰 영향을 미치고 있다. 특히 도시화된 대도시의 배수 시설 능력 부족은 돌발 강우, 국지성 집중 호우로 인한 침수 피해를 야기한다. 미국, 유럽, 일본 등의 선진국의 경우 대심도 저류배수터널을 설치하여 운영하고 있으며, 이에 대한 시설운영기준 및 매뉴얼 개발 등에 관한 연구가 활발히 이루어져 왔다. 그러나 국내에는 이와 같은 시설물에 대한 운영사례가 없고, 시설물 내 복잡한 수리 현상에 대한 수리모형 실험도 부족한 실정이다. 따라서 본 연구는 서울시 강서·양천 일대에 설치된 대심도 터널인 신월 빗물저류배수시설을 대상으로 선정하였으며, 안정적인 운영계획 수립을 위한 최적운영기준을 개발하고자 한다. 본 연구는 도시유역 강우유출모의에 적합한 XP-SWMM 모형을 활용하여 강우조건에 따라 달라지는 수직구별 유입유량, 도달시간 등의 유출특성을 반영하고 수문개방시간을 고려한 시설물 운영기준을 산정하였다. 본 연구의 결과는 도시유역 홍수예방을 위한 빗물저류배수시설의 안정적인 운영계획 수립 및 시설물 운영 매뉴얼 개발에 기여할 수 있을 것으로 기대된다.

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Sewer overflow simulation evaluation of urban runoff model according to detailed terrain scale (상세지형스케일에 따른 도시유출모형의 관거월류 모의성능평가)

  • Tak, Yong Hun;Kim, Young Do;Kang, Boosik;Park, Mun Hyun
    • Journal of Korea Water Resources Association
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    • v.49 no.6
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    • pp.519-528
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    • 2016
  • Frequently torrential rain is occurred by climate change and urbanization. Urban is formed with road, residential and underground area. Without detailed topographic flooded analysis consideration can take a result which are wrong flooded depth and flooded area. Especially, flood analysis error of population and assets in dense downtown is causing a big problem for establishments and disaster response of flood measures. It can lead to casualties and property damage. Urban flood analysis is divided into sewer flow analysis and surface inundation analysis. Accuracy is very important point of these analysis. In this study, to confirm the effects of the elevation data precision in the process of flooded analysis were studied using 10m DEM, LiDAR data and 1:1,000 digital map. Study area is Dorim-stream basin in the Darim drainage basin, Sinrim 3 drainage basin, Sinrim 4 drainage basin. Flooding simulation through 2010's heavy rain by using XP-SWMM. Result, from 10m DEM, shows wrong flood depth which is more than 1m. In particular, some of the overflow manhole is not seen occurrence. Accordingly, detailed surface data is very important factor and it should be very careful when using the 10m DEM.